All-Solid-State Battery Cathode Structure for Dry Ion Path Formation
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Solution Overview
Problem
Conventional all-solid-state batteries face issues with ion conduction paths not being secured due to conductive fiber aggregates, leading to deteriorated battery performance when formed without solvents, and uneven distribution of solid electrolyte and active materials in the positive electrode layer.
Innovation Solution
The battery design includes a positive electrode layer with a solvent content of 50 ppm or less, featuring a plate-shaped compressed body made of conductive fiber aggregates and solid electrolyte, ensuring ion conduction paths by mixing solid electrolytes and conductive fibers in a dry manner, and optimizing the dimensions and proportions of the compressed body to stabilize the electrode layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a coating slurry is formed by mixing active material, solid electrolyte, and conductive fiber using a solvent, then the mixture is easy to handle and process, but the solvent may deteriorate the active material and solid electrolyte, and requires additional drying steps
Solution Approach 1:
The patent changes the physical state parameter of the mixing system from wet (slurry with solvent) to dry (powder mixture), eliminating the solvent medium while maintaining mixability through mechanical energy input during the dry mixing and pressing process
Solution Approach 2:
The patent extracts and removes the solvent component from the coating slurry formulation, creating a solvent-free dry mixture system that avoids solvent-related material deterioration while still achieving uniform distribution of components
2Reliability
If a dry mixture of active material and solid electrolyte is pressed without solvent, then material deterioration is avoided, but ion conduction paths are not secured due to conductive fiber aggregates
Solution Approach 1:
The patent applies local quality control by specifying that conductive fibers should be distributed uniformly throughout the coating layer rather than aggregated, ensuring that ion conduction paths are maintained locally across the entire electrode structure
Solution Approach 2:
The patent performs preliminary action by pre-mixing the active material, solid electrolyte, and conductive fiber in specific proportions before pressing, ensuring that conductive fibers are evenly distributed throughout the mixture to prevent aggregate formation during the pressing process
3Power
If conductive fiber aggregates form in the positive electrode layer, then electron conduction is improved, but ion conduction paths are blocked and battery performance deteriorates
Solution Approach 1:
The patent applies homogeneity by ensuring uniform distribution of conductive fibers throughout the coating layer in a dispersed state, creating a homogeneous structure that simultaneously maintains both electron conduction pathways and ion conduction paths without localized aggregation
4Ease of manufacture
If solid electrolyte and active material are unevenly distributed in the positive electrode layer, then manufacturing is simplified, but battery performance and reliability are compromised
Solution Approach 1:
The patent performs preliminary action by pre-mixing all components (active material, solid electrolyte, and conductive fiber) in predetermined proportions before the coating process, ensuring uniform distribution is achieved before deposition onto the current collector
Solution Approach 2:
The patent changes the mixing process parameters from wet slurry mixing to dry powder mixing with controlled mechanical energy input, achieving uniform distribution of materials while maintaining the simplicity of the coating process
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 approach enhances ion conductivity and electron conduction, stabilizes battery performance, and prevents capacity loss by securing uniform distribution of active materials, even in the absence of solvents, thereby improving overall battery efficiency.
Implementation Method 1
a solid electrolyte that conducts lithium (Li) ions
Implementation Method 2
a plate-shaped compressed body between the positive electrode active materials, the plate-shaped compressed body including at least a part of the first solid electrolyte and at least a part of the conductive fiber
Data Source
AI summary
All-solid-state battery (100) includes positive electrode current collector (7), positive electrode layer (20) including positive electrode active materials (3), solid electrolyte (1), a solid electrolyte (2), and conductive fiber (9), solid electrolyte layer (40) including solid electrolyte (6), negative electrode layer (30) including negative electrode active material (4) and solid electrolyte (5), and negative electrode current collector (8), all of which are stacked in this order. Positive electrode layer (20) includes a solvent component of 50 ppm or less. Positive electrode layer (20) includes plate-shaped compressed body (11) between positive electrode active materials (3), the plate-shaped compressed body including at least a part of solid electrolyte (1) and at least a part of conductive fiber (9). Compressed body (11) has a first maximum length in a first direction orthogonal to a thickness direction of compressed body (11) and a second maximum length in a second direction orthogonal to the thickness direction of compressed body (11) and the first direction, at least one of the first maximum length and the second maximum length being 5 times or more and 50 times or less an average thickness of compressed body (11).