All-Solid-State Cell Laminate Edge Structure Against Short Circuits
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Solution Overview
Problem
All-solid state secondary cells face issues with short circuits due to differences in thickness and consolidation of electrode layers, leading to weak end parts that are collapsible during pressing, which compromises the strength and integrity of the laminate.
Innovation Solution
The solution involves an all-solid state secondary cell design where the powder laminate has a solid electrolyte layer covering the outer peripheries of the positive and negative electrode powder layers, with the thickness of the peripheral edge part being equal to or greater than the center part, and a production method that includes bonding an insulating member, disposing powder layers, and pressing the collectors to ensure even pressure and consolidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the solid electrolyte layer is disposed between positive and negative electrode powder layers with uniform thickness, then the cell structure is simple and easy to manufacture, but the peripheral edge part becomes weak and collapsible during pressing causing short circuits
Solution Approach 1:
The patent applies local quality by making the thickness of the solid electrolyte layer non-uniform, specifically making the peripheral edge part thicker than the center part. This local variation in thickness provides enhanced strength and collapse resistance at the peripheral edges where it is most needed, while maintaining simpler structure in the center region.
2Manufacturing precision
If the total thickness of end parts of electrode layers and solid electrolyte layer is different, then the forming pressure distribution becomes non-uniform, but this causes the end part of the laminate to be insufficiently consolidated and weak
Solution Approach 1:
The patent makes the peripheral edge part of the solid electrolyte layer thicker than the center part, creating local quality variation that compensates for the insufficient consolidation at the edges. This thicker peripheral edge provides the necessary strength and collapse resistance during pressing operations.
3Strength
If the peripheral edge part is made thicker to prevent collapse, then the strength and collapse resistance are improved, but the manufacturing complexity increases
Solution Approach 1:
The patent implements local quality by varying the thickness of the solid electrolyte layer only at the peripheral edge part, leaving the center part with uniform or reduced thickness. This targeted approach provides the necessary strength enhancement only where collapse resistance is critical, without unnecessarily complicating the overall cell structure or manufacturing process.
Data Source
AI summary
An all-solid state secondary cell comprises a positive electrode collector, a negative electrode collector, and a powder laminate disposed between the positive electrode collector and the negative electrode collector. The powder laminate has a positive electrode powder layer, a negative powder layer, a solid electrolyte layer disposed between the positive electrode powder layer and the negative electrode powder layer, and an absorption layer covering an outer periphery of the positive electrode powder layer or the negative electrode powder layer. The absorption layer includes at least one of a hydrogen sulfide adsorption layer and a moisture adsorption layer. The powder laminate comprises a peripheral edge part and a center part surrounded by the peripheral edge part. A thickness of the peripheral edge part of the powder laminate is greater than a thickness of the center part of the powder laminate.