Multi-Layer Encapsulation for Thin Film Lithium-Ion Batteries

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Solution Overview

Problem

Thin film lithium-ion batteries face challenges with self-discharge and reduced service life due to sensitivity to humidity and mechanical stresses from volume variations of anode materials, leading to encapsulation failures and reduced performance over time.

Innovation Solution

A multi-layer encapsulation system comprising a first layer of electrically insulating material deposited by atomic layer deposition, a second layer of parylene or polyimide, and a third layer to protect against oxygen, ensuring impermeability and flexibility to accommodate battery dimension changes, while preventing short circuits and enhancing service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If thin film lithium-ion batteries use metallic lithium anodes with cyclic volume variation, then high energy density is achieved, but mechanical and electrical contacts between layers deteriorate and encapsulation cracks initiate

Engineering Contradiction:

Improveenergy densityVSAvoidservice life

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies flexible thin film encapsulation layers that can accommodate the cyclic volume variations of the metallic lithium anode during charge-discharge cycles. The thin film structure provides mechanical flexibility to maintain intimate contact between electrode and electrolyte layers while preventing crack initiation in the encapsulation system.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent employs composite material structures for the encapsulation system, combining multiple materials with complementary properties to simultaneously provide mechanical flexibility for volume accommodation and hermetic sealing for protection against humidity and oxygen, thereby resolving the contradiction between energy density and service life.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If the electrolyte film is made very thin to increase energy density, then higher power density is achieved, but self-discharge increases due to creeping short circuits at electrode edges

Engineering Contradiction:

Improvepower densityVSAvoidself-discharge

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent uses flexible thin film encapsulation that conforms to the electrode geometry, providing continuous coverage over electrode edges and protruding regions. This prevents creeping short circuits while maintaining the thin electrolyte film structure necessary for high power density.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent extends encapsulation coverage into the third dimension by covering protruding regions and electrode edges that extend beyond the main battery plane. This dimensional extension prevents self-discharge pathways at critical locations while preserving the thin-film high-power-density structure.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If conventional encapsulation systems are used, then manufacturing is simplified, but hermetic sealing is compromised due to cyclic stresses from anode volume variation

Engineering Contradiction:

Improveencapsulation simplicityVSAvoidsealing integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces conventional rigid encapsulation with flexible thin film structures that can dynamically accommodate cyclic volume changes of the anode during operation. This maintains hermetic sealing integrity while remaining compatible with manufacturing processes.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the mechanical parameters of the encapsulation system by transitioning from rigid to flexible materials with appropriate elastic moduli and thicknesses. This enables the encapsulation to withstand cyclic stresses from anode volume variation while maintaining sealing integrity.

Inventive Principle:

Principle #35Parameter changes

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 encapsulation system significantly reduces self-discharge and extends the service life of thin film lithium-ion batteries by providing a hermetic, flexible, and impermeable barrier against humidity and temperature, ensuring reliable operation over a longer period.

Implementation Method 1

a first layer of electrically insulating material deposited by atomic layer deposition

Methodology Applied

Scientific EffectAtomic layer deposition: Chemical Vapour Deposition

Implementation Method 2

providing a hermetic, flexible, and impermeable barrier against humidity and temperature

Methodology Applied

Scientific EffectPermeation barrier: Permeation

Data Source

PatentUS11469464B2Encapsulation system for electronic components and batteries

Publication Date: 2022.10.11 I TEN

AI summary

Systems, methods, and apparatus for encapsulating objects like that of microelectronic components and batteries. The system includes three successive layers that include a first covering layer composed of an electrically insulating material deposited by atomic layer deposition, which at least partly covers the object, a second covering layer that includes parylene and/or polyimide, and which is disposed on the first covering layer, and a third covering layer deposited on the second covering layer in such a way as to protect the second encapsulation layer, namely, with respect to oxygen, and thereby increase the service life of the object.