Flexible Secondary Battery Lead Layout for Curved Cell Durability
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Solution Overview
Problem
Secondary batteries with curved shapes face degradation issues at the positive and negative electrode lead connection portions due to stress concentration, particularly when attached and detached repeatedly, leading to cracks or breakages.
Innovation Solution
A flexible secondary battery design where the positive and negative electrode leads are connected at a midpoint or vicinity in the curved direction, with specific opening portions in the electrodes and separator to distribute stress evenly, reducing the likelihood of degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the positive electrode lead and negative electrode lead are connected to the side of the end portion in the curved direction, then the battery can be curved, but stress concentrates on the lead connection portions causing cracks or breakages
Solution Approach 1:
The patent extracts the lead connection portions from the high-stress end portion region and relocates them to the midpoint region, separating the curved shape functionality from the lead connection function to eliminate stress concentration at the connection points
Solution Approach 2:
Instead of connecting leads at the conventional end portions, the patent inverts the connection location to the midpoint of the battery, reversing the typical design approach to achieve stress distribution and prevent degradation
2Adaptability or versatility
If the battery is made flexible with a laminated film exterior body, then the battery can be curved and adapt to body contours, but the electrode tabs become more susceptible to degradation
Solution Approach 1:
The patent applies different structural qualities to different regions: the exterior body uses flexible laminated film for adaptability, while the electrode structure uses elongated tabs with specific dimensions and materials to provide localized strength and resistance to degradation at critical areas
Solution Approach 2:
The patent employs composite material structures including the laminated film exterior body composed of multiple layers, and the electrode tabs using composite materials that combine flexibility with strength to resist degradation while maintaining the overall flexibility of the battery
Data Source
AI summary
A secondary battery that has flexibility and can inhibit degradation of a positive electrode lead connection portion or a negative electrode lead connection portion is provided. The secondary battery has a structure in which a positive electrode lead is connected to a positive electrode current collector exposed portion of a first positive electrode and a positive electrode current collector exposed portion of a second positive electrode while penetrating through the inner side of one opening portion of a first separator, an opening portion of a first negative electrode, and one opening portion of a second separator; a negative electrode lead is connected to a negative electrode current collector exposed portion of a first negative electrode while penetrating through the inner side of the other opening portion of the first separator; and the negative electrode lead and the negative electrode current collector exposed portion of the first negative electrode are connected to a negative electrode current collector exposed portion of a second negative electrode while penetrating through the inner side of the other opening portion of the second separator, an opening portion of the first positive electrode, an opening portion of the second positive electrode, and the other opening portion provided in a third separator.