Negative Electrode Tab and Lithium Foil Layout for Pre-Lithiation

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Solution Overview

Problem

Existing lithium secondary batteries face challenges in minimizing irreversible capacity loss due to the formation of a Solid Electrolyte Interface (SEI) during the initial charge, and conventional pre-lithiation methods are costly and inefficient for mass production.

Innovation Solution

A method for preparing lithium secondary batteries involves forming a negative electrode active material layer on a current collector with a protruding tab, using a closed band-shaped lithium foil with an opening, and ensuring the negative electrode tab contacts the lithium foil without overlap, allowing pre-lithiation through aging without a separate process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional pre-lithiation methods are used, then initial reversibility is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improveinitial reversibilityVSAvoidpre-lithiation process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the pre-lithiation function with the negative electrode structure itself by integrating lithium foil directly into the electrode assembly. This eliminates the need for separate pre-lithiation processes while achieving the same effect of compensating for irreversible lithium loss during initial charging cycles.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The lithium foil is pre-installed in contact with the negative electrode active material before battery assembly is complete. This preliminary positioning ensures that lithium transfer occurs automatically during initial charging, compensating for SEI formation losses without requiring additional post-assembly processing steps.

Inventive Principle:

Principle #10Preliminary action

2Loss of energy

If separate pre-lithiation process is performed, then irreversible capacity loss is reduced, but manufacturing time and productivity decrease

Engineering Contradiction:

Improveirreversible capacity lossVSAvoidmanufacturing efficiency

Core Design Contradiction:

Loss of energyVSProductivity

Solution Approach 1:

The pre-lithiation functionality is merged into the negative electrode assembly process itself. The lithium foil is positioned and contacted with the active material during standard electrode manufacturing, eliminating the need for separate pre-lithiation processing steps and maintaining high manufacturing throughput.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The lithium foil automatically provides lithium ions to the negative electrode during initial charging cycles through direct contact. This self-service mechanism occurs naturally during normal battery operation without requiring external intervention or additional processing steps, thereby maintaining manufacturing efficiency.

Inventive Principle:

Principle #25Self-service

3Reliability

If lithium foil is disposed to overlap with negative electrode, then pre-lithiation efficiency improves, but risk of short circuit and safety issues increases

Engineering Contradiction:

Improvepre-lithiation efficiencyVSAvoidshort circuit risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The lithium foil is positioned to contact only specific local regions of the negative electrode where pre-lithiation is needed, rather than overlapping extensively. This localized contact approach maintains effective lithium transfer while minimizing the risk of short circuits and safety issues associated with widespread lithium-metal contact.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The lithium foil is configured as a closed band shape with an opening, creating segmented contact zones rather than continuous overlap. This segmentation allows controlled lithium transfer at contact points while preventing uncontrolled lithium diffusion and short circuiting that would occur with extensive overlapping.

Inventive Principle:

Principle #1Segmentation

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 enhances the initial reversibility of the lithium secondary battery by facilitating lithium transfer to the active material layer, improving electrochemical performance without the need for a separate pre-lithiation process.

Implementation Method 1

a process of intercalating and deintercalating lithium ions from the positive electrode active material of the positive electrode into and out of the negative electrode active material of the negative electrode

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

disposing a negative electrode tab so as to be in contact with the lithium foil

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3872916B1Method of preparing lithium secondary battery

Publication Date: 2026.03.18 LG ENERGY SOLUTION LTD

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AI summary

The present invention relates to a method of preparing a lithium secondary battery which may effectively perform pre-lithiation, wherein, according to the present invention, a closed square band-shaped lithium foil having an opening formed at a center thereof is prepared during the preparation of the lithium secondary battery, and a negative electrode is disposed in the opening of the lithium foil, but pre-lithiation of the negative electrode may be performed without a separate pre-lithiation process by disposing the negative electrode and the lithium foil so as not to overlap with each other and disposing a negative electrode tab so as to be in contact with the lithium foil.