Lithium-Ion Electrode Protective Layer Deposition

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Solution Overview

Problem

Existing methods for protecting electrodes in lithium-ion batteries result in loss of energy density due to incomplete coverage and lack of depth in the protective layer deposition, which fails to maintain high energy density properties while preventing secondary reactions and metal dissolution.

Innovation Solution

A method involving the deposition of a protective layer on the electrode after drying but before calendering, utilizing techniques like ALD or CVD to ensure uniform coverage and penetration within the electrode's porosity, maintaining electronic conduction and preventing secondary reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a protective layer is deposited on the electrode after drying but before calendering, then the coverage and penetration of the protective layer is improved, but the manufacturing process complexity increases

Engineering Contradiction:
Improveprotective layer coverageVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The protective layer is deposited on the electrode before the calendering step, while the electrode structure is still in its dried, porous state. This preliminary deposition allows the protective layer to penetrate and cover the active material more effectively before the structure is densified by calendering, thereby improving coverage without requiring additional post-calendering deposition steps.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the protective layer is deposited by ALD or CVD techniques, then the uniformity and depth of coverage is improved, but the manufacturing time and energy consumption increase

Engineering Contradiction:
Improveprotective layer uniformityVSAvoidmanufacturing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The electrode is maintained in its porous dried state during protective layer deposition, allowing ALD or CVD techniques to penetrate deeper and achieve more uniform coverage throughout the electrode structure. The porous architecture enables better access of deposition precursors to the active material surfaces, improving uniformity while the single deposition step keeps time consumption manageable.

Inventive Principle:
Principle #31Porous materials

3Reliability

If the protective layer thickness is increased to prevent secondary reactions, then the protection effectiveness is improved, but the energy density of the electrode decreases

Engineering Contradiction:
Improveprotection effectivenessVSAvoidenergy density
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

By depositing the protective layer on the porous dried electrode structure, the coating penetrates and covers the active material throughout the electrode thickness. This enables effective protection with thinner overall layer thickness compared to surface-only deposition on calendered electrodes, thereby maintaining energy density while ensuring comprehensive protection against secondary reactions and metal dissolution.

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

This approach enhances the coverage and contact between the active material and conductive additives, maintaining high energy density while preventing secondary reactions and metal dissolution, thus improving the electrode's performance and lifespan.

Implementation Method 1

The protective layer thus fulfills the role of: prevent side reactions between the cathode and the electrolyte

Methodology Applied
Scientific EffectPhysical barrier formation:

Implementation Method 2

trap undesirable species resulting from the degradation of the electrolyte

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 3

suppress the dissolution of transition metals present in the active material of the cathode

Methodology Applied
Scientific EffectChemical barrier formation:

Implementation Method 4

the deposition is generally carried out by PVD (physical vapor deposition)

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 5

drying of the ink

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3050140B1Method for producing an electrode for a lithium-ion battery
Publication Date: 2019.03.20 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3050140B1 patent drawingFigure 1~4b

AI summary

The invention relates to a method for producing an electrode for a secondary battery, said method comprising the following steps: deposition of an ink comprising at least one active electrode material on a substrate; drying of the ink; deposition of a protective layer on the previously dried ink; and calendering of the electrode formed in this way.