Cable Battery Packaging with Wing Seal for Flexibility
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Solution Overview
Problem
Cable-type secondary batteries face issues with electrode active material layer separation due to external forces and volumetric swelling, leading to decreased capacity and cycle life, as conventional packaging is not skin-tightly formed and lacks flexibility.
Innovation Solution
A cable-type secondary battery design featuring a packaging structure with a water barrier film, sealant polymer layers, and a mechanical support layer, where the packaging is sealed and folded to form a wing portion for enhanced flexibility and adhesion, and optionally enclosed in a heat shrinkable tube for additional sealing and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packaging is used for cable-type secondary battery, then the packaging can be easily manufactured, but the packaging cannot be formed skin-tightly and lacks flexibility, causing electrode active material layer separation
Solution Approach 1:
The packaging is divided into multiple functional layers: a flexible substrate layer, a sealant layer for skin-tight sealing, and a wing portion for adhesion. This segmentation allows each layer to perform its specific function while collectively providing the required reliability without excessive overall complexity.
Solution Approach 2:
The packaging uses composite material structure combining flexible substrate material with sealant material. This composite approach provides both the flexibility needed to prevent electrode separation and the sealing capability to maintain battery integrity, resolving the contradiction between reliability and complexity.
2Strength
If the packaging is made rigid to protect from external forces, then protection is improved, but flexibility is reduced and electrode separation occurs during charging/discharging
Solution Approach 1:
The packaging employs a flexible substrate layer that can deform with the electrode assembly during charging and discharging cycles. This flexible shell structure maintains protection from external forces while adapting to volumetric changes, preventing electrode separation and maintaining battery performance.
3Reliability
If the packaging is formed skin-tightly to prevent separation, then electrode adhesion is improved, but manufacturing complexity increases
Solution Approach 1:
The wing portion is pre-formed as an integral part of the packaging structure during the packaging manufacturing process. This preliminary action ensures proper adhesion geometry is already in place before battery assembly, simplifying the overall manufacturing process while achieving reliable electrode adhesion through the skin-tight formation.
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 provides a skin-tightly formed packaging that enhances flexibility, prevents electrode separation, and improves battery capacity and cycle life by ensuring secure adhesion and protection against external forces and water infiltration.
Implementation Method 1
a portion of the packaging is overlapped at an end thereof and sealed by heat compression
Implementation Method 2
inserting the electrode assembly surrounded with the packaging into a heat shrinkable tube, followed by heating so that the heat shrinkable tube is shrunk
Data Source
Figure 1
Figure 2a~2b
Figure 3~4
AI summary
The present disclosure provides a cable-type secondary battery, which has a packaging formed skin-tightly on the outer surface of an electrode assembly to improve flexibility significantly even when external force is applied to the cable-type secondary battery, and to prevent a decrease in capacity of the battery, thereby providing improved cycle life characteristics. The cable-type secondary battery comprises an electrode assembly comprising an electrode assembly comprising an inner electrode, a separator layer formed to surround the inner electrode, and an outer electrode formed to surround the outer surface of the separator layer; and a packaging surrounding the electrode assembly, wherein the packaging surrounds the top surface and the bottom surface of the electrode and a portion of the packaging is overlapped at an end thereof and sealed by heat compression, and the overlapped part is folded along the perimeter of the packaging to be a wing portion. The present disclosure also provides a method for manufacturing the cable-type secondary battery.