All-Solid-State Cell Peripheral Edge Thickness Gradient
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Solution Overview
Problem
The all-solid state secondary cell's laminate structure is collapsible at the edges due to uneven thickness and pressure distribution, leading to potential short circuits between positive and negative electrodes.
Innovation Solution
Incorporating an outer peripheral member to evenly distribute pressure across the powder laminate and the collectors, ensuring the thickness of the peripheral edge part is equal to or greater than the center part, and using a production method where the positive and negative electrode collectors are pressed together to generate equal pressure on both the powder laminate and the outer peripheral member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the solid electrolyte layer is extended beyond the electrode powder layers at the peripheral edges, then short circuit prevention is improved, but the laminate becomes collapsible at the edges due to uneven thickness and pressure distribution
Solution Approach 1:
The invention applies local quality by creating a thickness gradient in the solid electrolyte layer, where the peripheral edge part has greater thickness than the center part. This local variation in thickness provides enhanced structural support and consolidation at the vulnerable peripheral edges while maintaining the extended coverage for short circuit prevention.
2Strength
If the peripheral edge part of the solid electrolyte layer is made thicker to prevent collapse, then laminate strength is improved, but production complexity increases
Solution Approach 1:
The invention employs parameter changes by varying the thickness parameter of the solid electrolyte layer across different regions. The thickness transitions from a first value at the center to a second value (greater than the first) at the peripheral edge part, achieving enhanced strength without requiring complex multi-component structures.
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
This configuration prevents short circuits by ensuring the peripheral edge part is securely compacted, enhancing the structural integrity and preventing collapsibility, thereby improving the cell's performance and reliability.
Implementation Method 1
pressing the positive electrode collector and the negative electrode collector in a direction in which the collectors are brought close to each other generates an equal pressure on both the powder laminate and the outer peripheral member by the pressing
Implementation Method 2
the outer peripheral member is made of an elastic material... T' is a thickness of the powder laminate to be made equal to the thickness of the outer peripheral member by the pressing
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention provides an all-solid state secondary cell (1) equipped with: a positive electrode collector (10); a negative electrode collector (30); and a powder laminate (40) placed between the positive electrode collector (10) and the negative electrode collector (30). The powder laminate (40) has: a positive electrode powder layer (14); a negative electrode powder layer (34); and solid electrolyte layers (23, 24) that are placed between the positive electrode powder layer (14) and the negative electrode powder layer (34), and also cover the outer periphery of the positive electrode powder layer (14) and the negative electrode powder layer (34). The powder laminate (40) comprises a peripheral edge part (46), and a center part (49) surrounded by this peripheral edge part (46). The thickness of the peripheral edge part (46) is the thickness of the center part (49) or greater.