Window Frame Lithium Metal Separator for Battery Ion Supplementation

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Solution Overview

Problem

Lithium secondary batteries face challenges in effectively supplementing lithium ions to electrodes without increasing battery thickness or capacity, and existing methods either require inconvenient passage formation or non-uniform lithium ion supplementation.

Innovation Solution

A separator with a porous substrate and a window frame-shaped lithium metal layer on its outer surface, which surrounds the positive electrode, allowing for effective lithium ion supplementation without affecting the battery's thickness or capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a separate lithium electrode is stacked with the positive electrode and negative electrode, then lithium ions can be supplemented to the electrodes, but the overall thickness of the cell increases

Engineering Contradiction:

Improvelithium ion supplementationVSAvoidcell thickness

Core Design Contradiction:

Quantity of substanceVSLength of stationary object

Solution Approach 1:

The patent combines the lithium electrode function with the separator by forming a lithium metal layer directly on the separator surface. This merging eliminates the need for a separate stacked lithium electrode, thereby supplementing lithium ions to the positive electrode without increasing the overall cell thickness.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The separator is given multiple functions: it continues to provide its traditional separation function while also serving as a lithium ion source through the lithium metal layer. This multi-functionality allows the separator to supplement lithium ions to the positive electrode during battery degradation without requiring additional structural components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Quantity of substance

If the lithium metal layer is formed on the separator, then lithium ions can be supplemented without increasing cell thickness, but the mechanical properties of the separator may be compromised

Engineering Contradiction:

Improvelithium ion supplementationVSAvoidseparator mechanical properties

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The lithium metal layer is formed locally on the separator surface rather than throughout the entire separator structure. This localized application allows the separator to maintain its mechanical integrity while providing lithium ions at the specific location where they are needed (at the positive electrode interface).

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent creates a composite structure by forming a lithium metal layer on the separator. This composite combines the mechanical strength of the separator material with the lithium ion-supplementing capability of the lithium metal layer, achieving both structural integrity and functional enhancement.

Inventive Principle:

Principle #40Composite materials

3Quantity of substance

If a third electrode with lithium metal is disposed away from the electrode assembly, then the cell thickness is not increased, but the lithium ion supplementation is not uniform across the electrode

Engineering Contradiction:

Improvelithium ion supplementationVSAvoiduniformity of lithium ion distribution

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent extracts the lithium metal from a separate electrode configuration and integrates it directly onto the separator surface adjacent to the positive electrode. This extraction and repositioning allows lithium ions to be supplied directly at the point of need, ensuring uniform supplementation across the positive electrode without the non-uniform distribution problems of distant placement.

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

The solution enables efficient lithium ion supplementation to the positive electrode, maintaining battery performance and preventing internal short circuits, while ensuring the battery's mechanical properties and capacity are not compromised.

Implementation Method 1

a lithium metal layer which is formed on an outer circumferential surface of the porous substrate and has a window frame shape with an empty interior

Methodology Applied

Scientific EffectIon diffusion: Diffusion

Implementation Method 2

a porous substrate; and a lithium metal layer formed on one side of the porous substrate

Methodology Applied

Scientific EffectPorosity: Porosity

Data Source

PatentUS11362401B2Separator for lithium secondary battery and lithium secondary battery including the same

Publication Date: 2022.06.14 LG ENERGY SOLUTION LTD

AI summary

The present invention relates to a separator for a lithium secondary battery, which includes a porous substrate, and a lithium metal layer formed on one side of the porous substrate, wherein the lithium metal layer is formed on an outer circumferential surface of the porous substrate and has a window frame shape with an empty interior, and a lithium secondary battery including the same.