Flexible Secondary Battery Sealing with Edge Bonding

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Solution Overview

Problem

Existing secondary batteries lack flexibility in design, which limits their application in devices with curved or bent surfaces, such as wearable technologies and ergonomic electronic devices, as they are not designed to maintain stability and efficiency when bent.

Innovation Solution

A flexible secondary battery design featuring an electrode assembly sealed by multiple layers of composite packaging materials, including insulating and metal layers, with specific bonding portions and separation spaces to accommodate bending without stress concentration, ensuring the battery's stability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If secondary batteries are designed with rigid structures to ensure stability, then reliability is improved, but adaptability to curved or bent device shapes deteriorates

Engineering Contradiction:

Improvebattery stabilityVSAvoidadaptability to curved shapes

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The battery employs a flexible sealing bag constructed from multiple layers including polyethylene terephthalate (PET) and aluminum foil, which provides both structural integrity and flexibility. This multi-layer flexible packaging allows the battery to maintain its sealed environment while adapting to curved or bent device shapes, resolving the contradiction between stability and adaptability

Inventive Principle:

Principle #30Flexible shells and thin films

2Adaptability or versatility

If the battery is made flexible to accommodate curved surfaces, then adaptability is improved, but structural strength deteriorates

Engineering Contradiction:

Improveflexibility for curved surfacesVSAvoidstructural strength

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The sealing bag utilizes a composite structure with multiple layers including PET and aluminum foil, where each layer contributes different properties. The PET provides flexibility and tensile strength, while the aluminum foil provides barrier properties and structural support. This composite material approach enables the battery to be flexible enough for curved surfaces while maintaining adequate structural strength

Inventive Principle:

Principle #40Composite materials

3Reliability

If bonding portions are increased to prevent separation, then reliability is improved, but stress concentration during bending increases

Engineering Contradiction:

Improvebonding stabilityVSAvoidstress concentration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sealing bag is divided into multiple functional layers (PET layer, aluminum foil layer, adhesive layers) rather than using a single homogeneous bonding structure. This segmentation allows each layer to handle different aspects of bonding and stress distribution, preventing stress concentration at single bonding points while maintaining overall bonding stability during bending

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP2884560B1Flexible secondary battery

Publication Date: 2019.02.20 SAMSUNG SDI CO LTD

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AI summary

A flexible secondary battery includes an electrode assembly and external material surrounding the electrode assembly having at least one bonding portion, wherein the external material is bonded to itself at the at least one bonding portion, and the at least one bonding portion extends in a lengthwise direction of the electrode assembly at an edge of the electrode assembly.