Current Collector Slit Layout for Bendable Battery Reliability

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Solution Overview

Problem

Wearable electronic devices face limitations in operation time due to the weight and compactness of secondary batteries, which require a balance between light weight, small size, and long usage, while maintaining reliability and preventing structural issues like positional shifts and tension-related cracks during bending.

Innovation Solution

The use of laser processing to create complex shapes in secondary battery electrodes, including cuts and openings, to relieve tension and prevent positional shifts, combined with an embossed exterior body that allows for flexible bending and stress relief, ensuring the battery's reliability and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the battery is made lightweight and compact for wearable devices, then the device portability is improved, but the operation time is limited

Engineering Contradiction:

Improvebattery weightVSAvoidoperation time

Core Design Contradiction:

Weight of moving objectVSDuration of action of moving object

Solution Approach 1:

The patent applies flexible thin film structures to the battery electrodes and packaging, enabling the battery to be made lightweight and compact while maintaining sufficient capacity for wearable devices. The flexible film structure allows the battery to achieve both reduced weight and extended operation time by optimizing the electrode configuration and active material distribution within the compact form factor.

Inventive Principle:

Principle #30Flexible shells and thin films

2Adaptability or versatility

If the battery is bent to fit wearable device shapes, then the adaptability is improved, but cracks and structural failure occur

Engineering Contradiction:

Improvebending adaptabilityVSAvoidstructural integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces cuts and openings in the electrode structures, dividing the continuous electrode material into segmented regions. This segmentation allows the electrode to flex and bend without creating continuous stress paths that would lead to cracks, thereby maintaining structural integrity while achieving the required bending adaptability for wearable device integration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different structural characteristics to different regions of the battery. Specifically, cuts and openings are strategically positioned in areas that experience high stress during bending, while other regions maintain continuous structure for optimal electrical performance. This local differentiation of structural quality enables the battery to achieve both flexibility and reliability.

Inventive Principle:

Principle #3Local quality

3Reliability

If laser processing is used to create complex electrode shapes, then the tension relief and crack prevention are improved, but the manufacturing complexity increases

Engineering Contradiction:

Improvecrack preventionVSAvoidelectrode shape complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical cutting methods with laser processing to create the complex electrode shapes with cuts and openings. This substitution enables precise and flexible fabrication of intricate patterns that would be difficult to achieve mechanically, while the laser process can be controlled to produce the required geometries with high precision and repeatability, managing the manufacturing complexity through advanced processing control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enables the development of flexible and bent secondary batteries that can be repeatedly bent without cracking, maintaining efficient current flow and extending the operational life of wearable devices by reducing stress and preventing short circuits.

Implementation Method 1

In the case where a plurality of electrodes is bent, the plurality of electrodes is bent with different curvatures. An electrode far from a curvature center is more bent than an electrode close to the curvature center... The use of laser processing to create complex shapes in secondary battery electrodes, including cuts and openings, to relieve tension and prevent positional shifts

Methodology Applied

Scientific EffectLaser processing: Laser

Implementation Method 2

an embossed exterior body that allows for flexible bending and stress relief, ensuring the battery's reliability and durability

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS20240429360A1Current collector, secondary battery, electronic device, and manufacturing method thereof

Publication Date: 2024.12.26 SEMICON ENERGY LAB CO LTD

AI summary

Part of an electrode, specifically a current collector and an active material layer, for a secondary battery is subjected to cutting processing to have a complex shape. For example, a stack of the first current collector and the first active material layer has a first slit and a second slit. Each of the first slit and the second slit passing across the first current collector and the first active material layer and extending from an edge of the first current collector. Another stack of the second current collector and the second active material layer has a third slit and a fourth slit. Each of the third slit and the fourth slit passing across the second current collector and the second active material layer and extending from an edge of the second current collector.