Flexible Battery Pouch Design for Bending Durability

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Solution Overview

Problem

Conventional lithium-ion batteries with a metal can structure are inflexible and difficult to integrate into thin, small, and flexible electronic devices, as they suffer from performance degradation and safety issues such as ignition and explosion due to repeated bending, which limits their application in mobile devices.

Innovation Solution

A flexible battery manufacturing method that involves forming a positive and negative electrode assembly with a back spring percentage of 3.5% or less, using specific conductive materials and PVDF ratios, and encapsulating the assembly with a separator and electrolyte in a flexible pouch, preventing cracks and peeling during bending.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal can structure is used for lithium-ion batteries, then the battery has high structural strength and reliability, but the battery becomes inflexible and difficult to integrate into thin, small, and flexible electronic devices

Engineering Contradiction:

Improvestructural strengthVSAvoidflexibility

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The patent replaces the rigid metal can structure with a flexible pouch structure made of thin film materials. The pouch-type battery uses flexible packaging that can bend and conform to different shapes, enabling integration into thin and flexible electronic devices while maintaining structural integrity through the layered electrode and pouch design.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The battery is segmented into distinct functional layers including positive electrode, negative electrode, separator, and pouch packaging. This segmentation allows each component to be optimized independently - the pouch provides flexibility while the internal layered structure maintains structural strength and electrochemical functionality.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If repeated bending occurs in conventional pouch-type batteries, then the battery achieves flexibility, but the exterior material and electrode assembly are damaged due to repetitive contraction and relaxation

Engineering Contradiction:

ImproveflexibilityVSAvoiddurability under bending

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent incorporates a buffer layer or cushioning structure within the pouch-type battery assembly that absorbs and distributes the mechanical stress from repeated bending. This beforehand cushioning prevents direct transmission of bending forces to the electrode assembly, reducing damage from repetitive contraction and relaxation while maintaining flexibility.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The pouch structure uses composite materials combining multiple layers with different mechanical properties - flexible outer layers for bendability and stronger internal layers for structural support. This composite construction allows the battery to withstand repeated bending without damaging the electrode assembly while maintaining flexibility for integration into thin devices.

Inventive Principle:

Principle #40Composite materials

3Length of moving object

If the battery structure is made thinner and more flexible, then the battery can be integrated into thin electronic devices, but the energy density and capacity are reduced

Engineering Contradiction:

ImprovethicknessVSAvoidenergy density

Core Design Contradiction:

Length of moving objectVSQuantity of substance

Solution Approach 1:

The patent optimizes the thickness parameters of each layer (electrode, separator, pouch) to achieve the desired thin profile while adjusting the composition and density of active materials to maintain energy density. By changing parameters such as electrode coating thickness, material composition ratios, and pouch layer configurations, the battery achieves both thinness for device integration and sufficient energy density for practical use.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20210036376A1Flexible battery, method for manufacturing thereof and supplementary battery comprising the same

Publication Date: 2021.02.04 AMOGREENTECH CO LTD

AI summary

A flexible battery and method for manufacturing a flexible battery in which an electrode assembly is encapsulated by an exterior material with an electrolyte. The flexible battery may be provided with an electrode assembly manufactured by forming a positive electrode mixture by coating and drying a composition for forming a positive electrode active material on part or all of at least one surface of a positive electrode current collector; vacuum drying the positive electrode current collector to manufacture a positive electrode; forming a negative electrode mixture by coating and drying a composition for forming a negative electrode active material on part or all of at least one surface of a negative electrode current collector; vacuum drying the negative electrode current collector to manufacture a negative electrode; and laminating by interposing a separator between the positive electrode and the negative electrode.