Solid-state battery edge portion thickness design
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Solution Overview
Problem
Solid-state batteries experience cracks during charging due to stress generated from the expansion of positive and negative electrodes, while the insulating layers do not expand, leading to potential structural failure.
Innovation Solution
The design includes first and second edge portions with thicknesses greater than the functional portion, specifically 1.01 to 1.15 times thicker, to alleviate stress and prevent cracking by distributing the expansion stress effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the solid-state battery uses solid electrolyte without electrolytic solution, then safety and high-temperature performance are improved, but cracks occur during charging due to stress from electrode expansion
Solution Approach 1:
The patent modifies the thickness parameter of edge portions relative to the functional portion. By setting the edge portion thickness to 1.01-1.15 times the functional portion thickness, the structure can accommodate electrode expansion stress without cracking, thus resolving the contradiction between safety and structural integrity.
Solution Approach 2:
The increased thickness of edge portions acts as a pre-designed stress buffer zone. This additional material thickness provides beforehand cushioning against the expansion stress that occurs during charging, preventing cracks before they can form in the functional portion.
2Volume of moving object
If the insulating layers are made thinner to reduce battery size, then device compactness is improved, but stress concentration occurs at the interface between insulating layers and electrodes during charging
Solution Approach 1:
The patent applies different thickness qualities to different locations: the functional portion maintains minimal thickness for compactness, while edge portions have increased thickness (1.01-1.15 times the functional portion thickness) to provide stress resistance. This local differentiation resolves the contradiction between compactness and crack resistance.
3Quantity of substance
If the functional portion thickness is reduced to increase energy density, then energy density is improved, but the battery becomes more susceptible to cracking under expansion stress
Solution Approach 1:
The battery structure is segmented into functional portions (for energy storage) and edge portions (for stress resistance). This segmentation allows the functional portion to be thin for high energy density while edge portions provide the necessary stress resistance, resolving the contradiction between energy density and stress resistance.
Data Source
AI summary
A solid-state battery having a battery body that includes a functional portion, a first edge portion, and a second edge portion. The functional portion is a portion where first and second internal electrodes and a solid electrolyte layer overlap each other in a thickness direction. The first edge portion is a portion where the first internal electrode, the solid electrolyte layer, and a second insulating layer overlap each other in the thickness direction. The second edge portion is a portion at which the second internal electrode, the solid electrolyte layer, and a first insulating layer overlap each other in the thickness direction. Each of thicknesses of the first and second edge portions are greater than a thickness of the functional portion.