Partial Gel Polymer Separator for Lithium Battery

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Solution Overview

Problem

Rechargeable lithium batteries face challenges in achieving uniform electrolyte impregnation and close contact between electrodes and separators, leading to non-uniform battery performance, rapid deterioration, and safety issues due to local lithium precipitation, especially when using gel polymers that hinder electrolyte impregnation and affect high-rate discharge properties.

Innovation Solution

A separator is partially coated with a gel polymer over 40-60% of its area using a gravure coating method, creating a patterned design that allows for rapid and uniform electrolyte impregnation and gas discharge, maintaining close contact between electrodes and separators, thereby preventing premature deterioration and enhancing battery performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the separator is totally coated with a gel polymer, then close contact between electrode and separator is improved, but electrolyte impregnation and wetting are hindered

Engineering Contradiction:

Improveclose contact between electrode and separatorVSAvoidelectrolyte impregnation rate

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The separator is divided into two distinct regions: a gel polymer-coated region (40-60% of total area) that provides close contact between electrode and separator, and a non-coated region that allows rapid electrolyte impregnation. This segmentation resolves the contradiction by assigning different functions to different parts of the separator surface.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the separator are given different properties: the coated region has high adhesion quality for electrode contact, while the non-coated region has high permeability quality for electrolyte flow. This local differentiation allows both contradictory requirements to be satisfied in their respective zones.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If the separator is totally coated with a gel polymer, then uniform contact is improved, but high-rate discharge property deteriorates

Engineering Contradiction:

Improveuniform contact between electrode and separatorVSAvoidhigh-rate discharge property

Core Design Contradiction:

Manufacturing precisionVSPower

Solution Approach 1:

The separator surface is segmented into coated and non-coated areas, allowing uniform contact in the coated region while maintaining high-rate discharge capability through the non-coated region that facilitates rapid electrolyte access to the electrode.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The separator exhibits local quality differentiation where the coated region provides uniform contact precision, while the non-coated region provides high power throughput, resolving the contradiction between manufacturing precision and power performance.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If electrode and separator are simply stacked, then manufacturing simplicity is maintained, but uniform electrolyte distribution is difficult to achieve

Engineering Contradiction:

Improvestacking process simplicityVSAvoiduniform electrolyte distribution

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The gel polymer coating is applied to the separator in advance during manufacturing, creating a pre-configured structure that will automatically achieve uniform electrolyte distribution when assembled, eliminating the need for complex post-assembly adjustments while maintaining manufacturing simplicity.

Inventive Principle:

Principle #10Preliminary action

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 partial gel polymer coating ensures uniform electrolyte distribution, reduces battery resistance, improves high-rate discharge capabilities, and extends battery life by preventing gas trapping and lithium precipitation, resulting in enhanced battery performance and safety.

Implementation Method 1

lamination using a gel polymer can improve the close contact between an electrode and a separator

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

provide a path for rapid impregnation of an electrode with an electrolyte

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 3

uniform wetting of an electrode with an electrolyte

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS8003263B2Rechargeable lithium battery using separator partially coated with gel polymer

Publication Date: 2011.08.23 LG ENERGY SOLUTION LTD

AI summary

Disclosed are a separator for a battery, which is coated with a gel polymer over 40-60% of total separator area, and a rechargeable lithium battery using the separator. The separator partially coated with a gel polymer reduces the battery resistance so that the battery power can be improved. Additionally, the separator increases electrolyte impregnation rate and provides uniform electrolyte impregnation, thereby improving the life, capacity and high-rate discharge property of a battery. Further, the separator permits electrode reactions to be performed uniformly, thereby preventing lithium precipitation and improving the battery safety.