Sodium-Ion Partitioning Wall with Thin Electrode Chamber for Crack Resistance
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Solution Overview
Problem
Existing plate-like partitioning walls for sodium-sulfur batteries have low durability and safety issues due to the formation of cracks during manufacturing, limiting their practical use.
Innovation Solution
A plate-like partitioning wall with a thin foil-like or pore-like negative electrode chamber extending in two-dimensional directions, formed using a burn-out pattern or continuous pore formation member, which reduces the risk of cracks and increases mechanical strength, allowing sodium ion permeation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a burn-out pattern is embedded in granulated powder and subjected to pressure forming and CIP forming to create a negative electrode chamber, then a negative electrode chamber space can be formed, but cracks occur in the compacted body due to spring back of the burn-out pattern
Solution Approach 1:
The invention extracts and removes the problematic burn-out pattern after it has served its purpose of defining the negative electrode chamber space. By taking out the burn-out pattern after sintering, the source of spring back and crack formation is eliminated, while the desired chamber volume is preserved
Solution Approach 2:
The burn-out pattern is preliminarily embedded in the granulated powder before pressure forming and CIP forming to define the negative electrode chamber space. This preliminary positioning allows the chamber geometry to be established before the pattern is removed, preventing subsequent crack formation
2Shape
If thin plates of β-alumina are attached together with a glass joining agent to form a plate-like partitioning wall with a negative electrode chamber, then a plate-like structure can be manufactured, but the durability performance does not exceed one month
Solution Approach 1:
The invention merges the negative electrode chamber formation into the sintering process itself rather than assembling separate thin plates with joining agents. The burn-out pattern is embedded in granulated powder and sintered as an integrated unit, eliminating weak joint interfaces and improving overall durability
Solution Approach 2:
The invention uses a composite structure where granulated β-alumina powder is sintered with a burn-out pattern embedded within. This composite approach creates a monolithic structure with the negative electrode chamber formed by the removed pattern, avoiding the need for glass joining agents and improving reliability
3Reliability
If a plate-like partitioning wall with a center negative electrode chamber space is designed, then sodium ion permeation can occur, but the mechanical strength is reduced and cracks occur during manufacturing
Solution Approach 1:
The invention uses granulated powder as a porous precursor material that, when sintered, forms a dense structure with an embedded burn-out pattern. The resulting monolithic structure maintains high mechanical strength while the removed pattern creates the necessary negative electrode chamber for sodium ion permeation
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
The solution provides a high-durability partitioning wall that maintains safety by minimizing heat generation and preventing ignition, even when damaged, due to the reduced sodium volume and enhanced mechanical strength.
Implementation Method 1
when a burn-out pattern is embedded in a center part of a granulated powder such as β-alumina and the resultant matter is subjected to pressure forming
Implementation Method 2
a solid electrolyte such as β-alumina allowing permeation of sodium ions Na+ therethrough forms a partitioning wall
Implementation Method 3
the front plate and the back plate are joined to this frame plate on the upper side and the lower side thereof with a glass joining agent
Data Source
AI summary
An object is to provide a plate-like partitioning wall allowing permeation of sodium ions therethrough and having high safety and durability.A plate-like partitioning wall 2 of the present invention is formed from a solid electrolyte allowing permeation of sodium ions therethrough. The plate-like partitioning wall 2 has a plate-like shape having, in a center part in the thickness direction thereof, a negative electrode chamber 20 to which molten sodium is supplied. This negative electrode chamber 20 is formed as a foil-like space extending in two-dimensional directions or as a pore-like space extending in two-dimensional directions in a net-like shape.The negative electrode chamber 20 of this plate-like partitioning wall 2 is formed as a thin foil-like space or as a fine pore-like space, and thus, the amount of molten sodium stored therein is very small. Therefore, even when this plate-like partitioning wall 2 is broken and reaction with molten sulfur occurs, the amount of heat generation is small, ignition is not caused, and thus, safety is high.The burn-out pattern and the organic matter powder forming the negative electrode chamber may also be those that are thin or fine. Thus, a small crack or the like is less likely to occur in the compacted body, and durability of the plate-like partitioning wall is high and manufacture thereof is facilitated.