Solid-State Battery Electrolyte Layer for Fracture Resistance
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Solution Overview
Problem
Conventional solid-state batteries face issues with fracture resistance due to differences in linear expansion coefficients with electronic circuit boards and damage from polishing processes, necessitating improvements in structural integrity.
Innovation Solution
The battery design includes a sintered electrolyte layer with controlled carbide distribution, where the mass ratio and grain boundary indices of carbides in the electrodes are lower than in the electrolyte layer, ensuring insulating properties and improved fracture resistance through grain boundary sliding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional solid-state batteries are produced by stacking and firing green sheets, then the battery can be manufactured, but the fracture resistance is insufficient due to stress from linear expansion differences and polishing damage
Solution Approach 1:
The patent applies local quality by creating distinct regions within the electrolyte layer with different carbide concentrations. The first region (near electrodes) has lower carbide content to maintain insulating properties, while the second region (central part) has higher carbide content to provide mechanical strength and fracture resistance. This spatial variation in material composition resolves the contradiction between structural integrity and electrical functionality.
Solution Approach 2:
The patent uses composite materials by combining oxide solid electrolyte with carbide particles derived from binder decomposition. The electrolyte layer forms a composite structure where the oxide matrix provides ionic conductivity and the carbide inclusions enhance mechanical strength and fracture resistance, directly addressing the weakness of conventional green sheet batteries.
2Strength
If the electrolyte layer has high carbide content to improve fracture resistance, then mechanical strength increases, but electrical insulation deteriorates
Solution Approach 1:
The patent resolves this contradiction by implementing local quality through spatially differentiated carbide distribution. The first region adjacent to electrodes maintains low carbide content to ensure electrical insulation, while the second region in the center has high carbide content for fracture resistance. This localized variation allows each region to optimize its function without compromising the other.
Solution Approach 2:
The electrolyte layer is segmented into multiple regions with different carbide concentrations. This segmentation allows the patent to independently optimize electrical insulation in electrode-interface regions and mechanical strength in central regions, resolving the trade-off between these conflicting requirements.
3Strength
If the battery structure is optimized for fracture resistance through carbide distribution, then mechanical durability improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies self-service by utilizing the binder material already present in the green sheet as a source of carbide. During the firing process, the binder decomposes and forms carbide particles in situ within the electrolyte layer. This eliminates the need for separate carbide addition steps or complex multi-stage manufacturing processes, achieving the desired carbide distribution through the inherent properties of the starting materials and standard firing conditions.
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 enhances the battery's fracture resistance and electrical isolation, reducing self-discharge and improving mechanical durability.
Implementation Method 1
improved fracture resistance through grain boundary sliding
Implementation Method 2
the electrolyte layer having an insulating property in the first region
Data Source
Figure 1~2
AI summary
A battery according to the present disclosure includes: a first electrode; a second electrode; and an electrolyte layer disposed between the first electrode and the second electrode so as to be in contact with the first electrode and the second electrode, wherein the first electrode is a sintered body including a first active material and a first oxide solid electrolyte, the electrolyte layer is a sintered body including a second oxide solid electrolyte, and includes: a first region including an interface between the first electrode and the electrolyte layer; and a central region including a center position in a thickness direction, the electrolyte layer having an insulating property in the first region, and a mass ratio of a carbide derived from a binder in the first electrode is lower than a mass ratio of a carbide derived from a binder in the central region of the electrolyte layer.