Lithium Battery Protection Layer Electrolyte Impregnation

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Solution Overview

Problem

Lithium secondary batteries face issues with inadequate impregnation of the electrolyte solution due to the low affinity of traditional laminating tapes with the electrolyte, leading to potential active material elimination and internal short-circuiting, especially in high-capacity battery packs.

Innovation Solution

Modifying the material of the protection layer or coating existing laminating tapes with polymers like polyvinylidene fluoride (PVdF) or surfactants that have an affinity for the electrolyte solution, enhancing wettability and dispersibility, and potentially incorporating a coating film with ester, hydroxy, or carboxylic groups to improve electrolyte impregnation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional laminating tape material is used for the protection layer, then the structure is simple and manufacturing is easy, but the affinity with electrolyte solution is low leading to poor impregnation

Engineering Contradiction:

Improveelectrolyte impregnationVSAvoidprotection layer material

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the chemical composition parameters of the protection layer material by introducing polymers containing ester groups, hydroxy groups, or carboxylic groups. These parameter changes increase the affinity with electrolyte solution, improving impregnation without fundamentally altering the laminating tape structure

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite protection layer by combining traditional laminating tape material with polymer materials that have high affinity for electrolyte solution. This composite structure maintains the protective function while adding the desired chemical properties for better electrolyte impregnation

Inventive Principle:

Principle #40Composite materials

2Reliability

If the protection layer material is modified to improve electrolyte affinity, then impregnation is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveelectrolyte impregnationVSAvoidprotection layer fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies polymer coatings to the laminating tape before assembly into the battery. This preliminary action ensures that the protection layer has the required electrolyte affinity before the battery is sealed, simplifying the overall manufacturing process while achieving better impregnation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent modifies the chemical parameters of the protection layer by incorporating specific functional groups (ester, hydroxy, carboxylic) that naturally provide high affinity for electrolyte solution, achieving improved impregnation through material selection rather than complex processing

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If high-capacity battery pack is used, then energy density is improved, but electrolyte impregnation becomes more difficult

Engineering Contradiction:

Improvebattery capacityVSAvoidelectrolyte impregnation

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the protection layer to increase electrolyte affinity, which compensates for the reduced impregnation efficiency in high-capacity battery packs with higher density electrode assemblies

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a coating layer that can be applied as a thin film on the laminating tape, providing sufficient electrolyte affinity enhancement without adding significant weight or volume, making it suitable for high-capacity battery designs where space and weight are critical

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

The modified protection layer significantly improves electrolyte impregnation, reducing the risk of active material elimination and internal short-circuiting, while also increasing production efficiency by enhancing wettability and dispersibility, and allowing for better surface contact with the electrolyte solution.

Implementation Method 1

The material of the protection layer has an affinity for the electrolyte solution due to a wettability and a dispersibility of the material against an electrolyte solution

Methodology Applied

Scientific EffectWettability: Wetting

Implementation Method 2

coating the material of an existing protection layer with an ingredient with an affinity for the electrolyte solution

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS7842414B2Lithium secondary battery

Publication Date: 2010.11.30 SAMSUNG SDI CO LTD

AI summary

A lithium secondary battery, and more particularly, a lithium secondary battery which can improve the impregnation of an electrolyte solution either by modifying the material of a protection layer, such as a laminating tape and others, to be formed to protect the elimination of active materials, into a material with an affinity for the electrolyte solution, or by coating the material of an existing protection layer with an ingredient with an affinity for the electrolyte solution.