Helically Wound Flexible Battery Electrodes Without a Separator
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Solution Overview
Problem
Conventional secondary batteries with plate-like electrode structures are inflexible, prone to short-circuits due to deformation, and limited in design applications, as they require specific installation spaces and are sensitive to volume changes during charging/discharging.
Innovation Solution
A flexible secondary battery design featuring longitudinally extended electrodes with insulation coating layers, helically wound in contact with each other, eliminating the need for a separator and allowing for free deformation without forming sharp portions that could cause short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a plate-like electrode structure is used, then high degree of integration is achieved, but flexibility and structural deformation capability are limited
Solution Approach 1:
The patent applies curvature by transitioning from flat plate-like electrodes to tubular electrodes with circular cross-sections. The tubular structure allows the battery to be bent and deformed while maintaining structural integrity, resolving the contradiction between integration and flexibility by enabling the battery to adapt to various installation spaces through its curved, flexible form factor.
2Productivity
If a plate-like electrode structure is used, then integration is improved, but sensitivity to volume change during charging/discharging increases
Solution Approach 1:
The patent employs flexible insulation coating layers that wrap around the tubular electrodes, forming a protective shell structure. These flexible coatings accommodate volume changes during charging and discharging without causing structural damage or short circuits, thereby reducing volume change sensitivity while maintaining the integrated tubular design.
3Shape
If conventional cylindrical or prismatic batteries are used, then specific shape requirements are met, but free deformation and design adaptability are limited
Solution Approach 1:
The patent implements a dynamic structure where the tubular electrodes and insulation coatings can elastically deform and bend without permanent damage. This dynamic flexibility allows the battery to adapt to various installation configurations and device designs, moving beyond the rigid shape constraints of conventional cylindrical or prismatic batteries while still providing structurally sound operation.
4Productivity
If plate-like electrodes are used, then integration is improved, but potential difference between electrodes increases
Solution Approach 1:
The patent combines the positive and negative tubular electrodes in a concentric configuration where one electrode is positioned inside the other, with insulation coatings ensuring proper electrical separation. This merged structure reduces potential differences between electrodes by improving current distribution and reducing resistance, while maintaining high integration through the compact tubular design.
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 flexible battery design enhances flexibility, prevents short-circuits, and maintains stability by dispersing force applied to the active material layers, allowing for improved deformation without damaging insulation coating layers or separating active materials from current collectors.
Implementation Method 1
each of the first and second insulation coating layers functions as an electrical insulation layer which prevents a short-circuit between the first electrode and the second electrode
Implementation Method 2
functions to form a channel through which lithium ions can be transported between both electrodes
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A flexible secondary battery includes: a first electrode including a first electrode current collector extended longitudinally, a first electrode active material layer formed on the outside of the first electrode current collector, and a first insulation coating layer formed on the outside of the first electrode active material layer; and a second electrode including a second electrode current collector extended longitudinally, a second electrode active material layer formed on the outside of the second electrode current collector, and a second insulation coating layer formed on the outside of the second electrode active material layer, wherein the first electrode and the second electrode are wound in such a manner that they are disposed alternately in contact with each other.