Cation Exchange Material for Lithium Battery Impurity Removal

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Solution Overview

Problem

Lithium secondary batteries face significant life characteristic deterioration due to internal short-circuiting caused by metal ion impurities incorporated during the assembly process, which cannot be completely prevented by existing methods.

Innovation Solution

Incorporation of a cation exchange material containing lithium, sodium, or ammonium ions into the battery's electrodes and/or separator to facilitate a cation exchange process that replaces harmful metal ions with non-detrimental ions, preventing electrodeposition and thus removing metal impurities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If metal ion impurities are incorporated during battery assembly process, then battery fabrication is simplified, but internal short-circuiting occurs and battery life characteristics deteriorate

Engineering Contradiction:
Improvebattery fabrication processVSAvoidbattery life characteristics
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by incorporating a cation exchange material into the battery structure before operation begins. This material proactively captures metal ion impurities as they are incorporated during assembly, preventing them from causing internal short-circuiting later. The cation exchange material is positioned in advance to intercept harmful ions before they can damage the battery, thus maintaining both ease of manufacture and reliability.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If water is removed from battery to prevent degradation, then battery performance stability improves, but metal ion impurities remain and cause internal short-circuiting

Engineering Contradiction:
Improvebattery performance stabilityVSAvoidmetal ion impurities
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a cation exchange material as an intermediary substance that specifically targets and captures metal ion impurities. This intermediary material acts as a mediator between the harmful metal ions and the battery components, preventing the ions from causing internal short-circuiting while not interfering with the already-improved stability from water removal. The cation exchange material selectively binds to metal ions, isolating them from critical battery components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If cation exchange material is added to remove metal ions, then battery life characteristics improve, but device complexity increases

Engineering Contradiction:
Improvebattery life characteristicsVSAvoidbattery structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the cation exchange material to perform multiple functions simultaneously: it captures metal ion impurities, prevents internal short-circuiting, and maintains battery performance stability. This multi-functional approach means that a single added component addresses multiple issues, reducing the need for separate systems for each function and thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent utilizes porous materials as the cation exchange medium, which provides a high surface area-to-volume ratio. This porous structure allows the material to effectively capture metal ion impurities throughout the battery without requiring large quantities of material or complex distribution systems. The porous nature enables efficient ion capture while maintaining a relatively simple overall battery structure.

Inventive Principle:
Principle #31Porous materials

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 cation exchange material effectively removes metal impurities, enhancing battery life characteristics by preventing internal short-circuiting and maintaining capacitance, as demonstrated by reduced voltage drops in experimental batteries.

Implementation Method 1

metal ion impurities incorporated during an assembly process of the battery are removed via a cation exchange process

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Implementation Method 2

to prevent electrodeposition of the metal ions on an anode

Methodology Applied
Scientific EffectElectrodeposition prevention: Electrodeposition

Data Source

PatentEP1952465B1Secondary battery of improved life characteristics by elimination of metal ions
Publication Date: 2013.11.06 LG CHEM LTD

AI summary

Disclosed herein is a lithium secondary battery having improved life characteristics by removal of metal ion impurities incorporated during an assembly process of the battery via a cation exchange process, thereby preventing electrodeposition of the metal ions on an anode, through the addition of a cation exchange material, containing cations selected from the group consisting of lithium, sodium, ammonium and any combination thereof, to an electrode and/or a surface of a separator.