Flexible Secondary Battery with Segmented Electrode Stack
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Solution Overview
Problem
Conventional batteries lack flexibility, leading to stress concentration and potential peeling at interfaces when bent, which can deteriorate performance and lifespan, and existing flexible batteries compromise on energy storage capacity to accommodate flexibility.
Innovation Solution
A flexible secondary battery design featuring an electrode stack structure with a fixing element at one end to maintain stability during bending, combined with a protection layer and reinforcement elements to manage stress and maintain alignment of layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the battery structure is made flexible to accommodate bending motions, then the adaptability and ease of operation are improved, but the structural stability and reliability deteriorate due to stress concentration and potential peeling at interfaces
Solution Approach 1:
The battery is divided into multiple layers (first electrode layer, separator, second electrode layer) with connection tabs at both ends. The fixing element selectively secures only the first end portion, allowing the second end portion to remain flexible for bending while maintaining overall structural integrity through the segmented layer design
Solution Approach 2:
The fixing element is applied locally only at the first end portion of the battery, creating a localized rigid region for stability while leaving the second end portion flexible for bending operations. This local differentiation resolves the contradiction between overall stability and localized flexibility
2Reliability
If the fixing element secures both end portions to maintain stability, then the structural reliability is improved, but the flexibility and ease of bending motion deteriorate
Solution Approach 1:
The battery structure is segmented into two distinct end portions with different functional requirements. The first end portion is secured by the fixing element for stability, while the second end portion remains unsecured to enable flexible bending motions, achieving both reliability and operational ease through spatial segmentation
Solution Approach 2:
The fixing element creates a localized rigid region at the first end portion only, allowing different mechanical properties at different locations. This local quality differentiation enables the battery to maintain stability where needed while remaining flexible where required for operation
3Strength
If the protection layer increases bending stiffness to prevent delamination, then the structural strength is improved, but the overall flexibility and adaptability deteriorate
Solution Approach 1:
The protection layer is applied selectively only at the first end portion where the fixing element is located, creating a localized reinforced region that prevents delamination at the secured end while maintaining flexibility at the unsecured second end portion
Solution Approach 2:
The protection layer segments the battery structure into a reinforced first end portion and a flexible second end portion, allowing the rigid protection to prevent delamination only where the fixing element is present while preserving bending flexibility elsewhere
Data Source
Figure 1A~1B
Figure 1C~3A
Figure 3B~5B
AI summary
A flexible secondary battery includes an electrode stack structure. The electrode stack structure includes a first electrode layer including a first metal current collector, a second electrode layer including a second metal current collector, a separator between the first electrode layer and the second electrode layer, connection tabs respectively extended from an end portion of the first metal current collector at a first end portion of the first electrode layer and an end portion of the second metal current collector at a first end portion of the second electrode layer; and a fixing element which fixes the end portions of the first and second metal current collectors only at a first end portion of the electrode stack structure. Second end portions of the first and second electrode layers opposite to the first end portions thereof are movable.