Electrode Laminate With 2n Bi-Cells For Lithium Battery
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Solution Overview
Problem
Conventional lithium secondary batteries face challenges in achieving a high capacity-to-thickness ratio and safety concerns due to limitations in electrode assembly design, particularly in prismatic or pouch-shaped batteries used for mobile devices and energy storage applications.
Innovation Solution
The electrode assembly is designed with 2n bi-cells, where a second separator covers sides without formed electrode terminals, and at least one outermost electrode is single-side coated, enhancing the capacity-to-thickness ratio and incorporating safety features to prevent short circuits and explosions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional electrode assembly design is used, then manufacturing simplicity is maintained, but capacity-to-thickness ratio is insufficient
Solution Approach 1:
The electrode assembly is divided into multiple unit cells (e.g., 5 unit cells) that are stacked in sequence. Each unit cell contains electrodes and separators arranged in a specific pattern, allowing the overall assembly to achieve higher capacity-to-thickness ratio while maintaining manageable complexity through modular design
Solution Approach 2:
Electrodes and separators are folded back and forth within each unit cell, creating a nested structure where multiple layers are contained within a compact space. This nesting approach maximizes the capacity-to-thickness ratio by efficiently utilizing the available volume
2Quantity of substance
If electrode assembly density is increased, then capacity-to-thickness ratio improves, but risk of short circuits and dendritic growth increases
Solution Approach 1:
Separators are positioned between adjacent electrodes of opposite polarity within each unit cell and between unit cells. These separators act as intermediary protective layers that prevent direct contact between electrodes, eliminating short circuit risks while allowing the assembly to maintain high density and capacity-to-thickness ratio
Solution Approach 2:
The electrode assembly design incorporates sufficient separator thickness and proper spacing between electrodes as preventive measures. This beforehand cushioning approach prevents dendritic growth by maintaining adequate separation distance, thereby ensuring safety against short circuits and explosions while achieving high capacity-to-thickness ratio
3Length of stationary object
If battery thickness is reduced for mobile device applications, then device miniaturization is achieved, but capacity is limited
Solution Approach 1:
The electrode assembly uses a folded and stacked three-dimensional structure instead of a simple planar arrangement. By folding electrodes back and forth and stacking multiple unit cells, the design achieves high capacity within a thin profile, effectively utilizing space in multiple dimensions to overcome the capacity limitation of thin batteries
4Reliability
If more separators are added to improve safety, then protection against short circuits is enhanced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The separator system is segmented into different functional zones: separators within unit cells and separators between unit cells. This segmentation allows for systematic arrangement that enhances safety while maintaining manufacturing feasibility through repetitive modular patterns
Solution Approach 2:
The separators serve multiple functions simultaneously: they prevent short circuits between adjacent electrodes, provide mechanical support for the electrode structure, and act as barriers against dendritic growth. This multi-functionality reduces the need for additional components, thereby limiting complexity increase despite enhanced safety
Data Source
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AI summary
Disclosed herein is an electrode assembly including 2n (n being a natural number equal to or greater than 1) polar bodies which are stacked.