Flexible Secondary Battery Current Collectors for Bend Durability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Secondary batteries with flexible designs face degradation issues with positive and negative electrode leads due to stress concentration when bent, leading to cracks or breaks, particularly at connection points, which limits their durability and functionality in wearable devices.
Innovation Solution
Incorporating stretchable structures for the positive and negative electrode current collectors, using conductive films with rubber elasticity and active material layers with rubber binders, allowing for curvature without significant degradation, and employing a novel stack configuration to distribute stress evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the positive electrode lead and negative electrode lead are connected to the end portion of the electrode in a curved direction, then the battery can be bent and curved, but stress concentrates on the connection portions causing cracks or breaks
Solution Approach 1:
The electrode is divided into a main body portion and an extended portion (electrode lead). The extended portion protrudes from the exterior body to form a separate connection point, allowing the battery to be bent without concentrating stress at the connection between the lead and the electrode tabs.
Solution Approach 2:
The electrode has different structures in different regions: the main body portion is enclosed within the exterior body while the extended portion protrudes outward. This local differentiation allows the connection portion to be positioned away from high-stress bending zones, improving reliability while maintaining flexibility.
2Strength
If the current collector is made rigid to maintain structural integrity, then the battery cannot be easily curved or bent
Solution Approach 1:
The battery structure is designed to accommodate dynamic bending movements. The extended electrode lead configuration allows the battery to transition between different shapes (curved and non-curved) without compromising the structural integrity of the current collector, as the flexibility is achieved through the overall geometry rather than material softening.
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 inhibits degradation of electrode current collectors, enabling flexible batteries to maintain performance and durability even when repeatedly bent, thus enhancing the lifespan and reliability of wearable devices.
Implementation Method 1
using conductive films with rubber elasticity and active material layers with rubber binders, allowing for curvature without significant degradation
Data Source
AI summary
A secondary battery that can inhibit degradation of an electrode is provided. A flexible secondary battery is provided. A flexible secondary battery includes a positive electrode, a negative electrode, and an exterior body surrounding the positive electrode and the negative electrode. The positive electrode includes a positive electrode current collector and a positive electrode active material layer provided over the positive electrode current collector. The negative electrode includes a negative electrode current collector and a negative electrode active material layer provided over the negative electrode current collector. One or both of the positive electrode current collector and the negative electrode current collector have rubber elasticity.