Electrode Structure with Segmented Separator Layer
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Solution Overview
Problem
Nonaqueous electrolyte secondary batteries face challenges in achieving high energy density while ensuring safety, particularly due to the risk of short circuits and current collector breakage, which reduces yield and product viability.
Innovation Solution
The electrode structure incorporates a current collector, a separator layer, and an active material layer with a specific ratio of coverage, where the separator layer covers the main surface and end faces of the active material layer, inhibiting short circuits and tab breakage by dispersing stress and enhancing adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the active material layer is made thicker to increase discharge capacity, then energy density is improved, but the risk of short circuits and current collector breakage increases
Solution Approach 1:
The patent divides the electrode structure into distinct functional layers: active material layer, separator layer, and protective layer. The separator layer is specifically positioned between the active material layer and current collector to segment the structure, providing electrical isolation that prevents short circuits while allowing the active material layer to maintain high discharge capacity.
Solution Approach 2:
The separator layer acts as an intermediary element between the active material layer and current collector. This intermediate layer provides mechanical support and electrical insulation, preventing direct contact between the active material and current collector that could cause short circuits, while still allowing efficient ion transport.
2Quantity of substance
If the active material layer is made thicker to increase discharge capacity, then energy density is improved, but current collector breakage risk increases
Solution Approach 1:
The patent applies local quality by providing different functional characteristics at different locations within the electrode structure. The separator layer is specifically positioned where mechanical stress is most likely to occur (between the thick active material layer and current collector), providing localized reinforcement and stress distribution to prevent current collector breakage.
Solution Approach 2:
The separator layer serves as a cushioning element that is positioned in advance between the active material layer and current collector. This pre-positioned protective layer absorbs and distributes mechanical stress before it can reach the current collector, preventing breakage even when the active material layer is thick.
3Reliability
If a separator layer is added to prevent short circuits, then safety is improved, but device complexity increases
Solution Approach 1:
The separator layer is designed to perform multiple functions simultaneously: it provides electrical insulation to prevent short circuits, mechanical support to reinforce the electrode structure, and ion transport pathways to maintain electrochemical performance. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
4Reliability
If the separator layer covers the end faces of the active material layer, then short circuit prevention is improved, but manufacturing precision requirements increase
Solution Approach 1:
The separator layer is designed with extended coverage that protrudes beyond the end faces of the active material layer. This preliminary extension ensures that even with normal manufacturing tolerances, the separator layer will cover the end faces and provide adequate electrical insulation, reducing the precision requirements for separator layer positioning during assembly.
Data Source
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AI summary
According to one approach, an electrode structure (10) is provided. The electrode structure (10) includes a current collector (11) , a separator layer (13), and an active material layer (12) including a main surface (121) and a first end face (122) other than the main surface (121). The active material layer (12) covers a first part (101) of at least one surface of the current collector (11). The separator layer (13) covers the main surface (121) of the active material layer (12), at least a part of the first end face (122) and second part (102) of the at least one surface of the current collector (11).