Flexible Micro-Battery Encapsulation via Neutral Plane Positioning

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Solution Overview

Problem

Existing encapsulation methods for micro-batteries, such as lithium batteries, face challenges in maintaining flexibility and preventing microcracks under bending stresses, which compromise the protective barrier's effectiveness.

Innovation Solution

A flexible encapsulation device with a thin protective barrier and a compensation cover, where the cover's thickness and Young's modulus are chosen to satisfy a specific equation, ensuring the micro-battery is positioned near the neutral plane of the composite structure, minimizing mechanical stresses and maintaining barrier integrity during bending.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a thin protective barrier layer is deposited on the micro-battery, then flexibility is improved, but the structure becomes vulnerable to microcracks under bending stresses

Engineering Contradiction:

ImproveflexibilityVSAvoidbarrier integrity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies composite materials by combining the thin protective barrier layer with a flexible support substrate. This composite structure allows the barrier to remain thin for flexibility while the support provides mechanical strength to prevent microcracks during bending operations.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes physical parameters by optimizing the thickness and material properties of both the protective barrier and flexible support. By carefully selecting these parameters, the structure achieves sufficient flexibility while maintaining barrier integrity under bending stresses.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a thick glass cover is used for encapsulation, then protection against species diffusion is improved, but flexibility is significantly reduced

Engineering Contradiction:

Improvediffusion barrier effectivenessVSAvoidflexibility

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces thick rigid glass covers with thin flexible barrier layers deposited on a flexible support. This thin-film approach maintains diffusion barrier effectiveness while enabling significant flexibility for applications like RFID labels and tire sensors.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the thickness parameter from millimeter-scale glass covers to micrometer-scale thin films. This parameter reduction maintains protective functionality while dramatically improving flexibility for wearable and flexible electronic applications.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If excessive bending stresses are applied to thin-layer encapsulation, then flexibility is demonstrated, but microcracks appear reducing protection

Engineering Contradiction:

ImproveflexibilityVSAvoidresistance to microcracks

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The patent creates a composite structure where the flexible support substrate provides mechanical strength and crack resistance, while the thin protective barrier maintains its protective function. The composite design allows bending without microcrack formation in the barrier layer.

Inventive Principle:

Principle #40Composite 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

The solution effectively reduces stress on the micro-battery, preventing microcracks and maintaining the protective barrier's integrity, even under significant bending forces, thus enhancing the long-term effectiveness of the encapsulation.

Implementation Method 1

the cover's thickness and Young's modulus are chosen to satisfy a specific equation, ensuring the micro-battery is positioned near the neutral plane of the composite structure, minimizing mechanical stresses

Methodology Applied

Scientific EffectNeutral plane positioning:

Implementation Method 2

a flexible encapsulation device with a thin protective barrier and a compensation cover, where the cover's thickness and Young's modulus are chosen to satisfy a specific equation

Methodology Applied

Scientific EffectComposite structure mechanics:

Implementation Method 3

Since materials containing lithium are very sensitive to air, and in particular to oxygen, nitrogen and humidity, they must be covered with an inert and waterproof protective barrier

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentEP2262036B1Device for flexible encapsulation of a micro-battery

Publication Date: 2012.03.21 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

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Figure 8~9

AI summary

The device has a thin layer forming a protective barrier (3) covering a microbattery (2) fully, and surface of flexible support at a periphery of the microbattery. A flexible compensation cover (5) arranged on the protective barrier is made from a material having a Young's modulus and a thickness chosen to satisfy predetermined equation with an accuracy of +- 30%. An independent claim is included for method for producing packaging device of microbattery.