All-solid-state battery interfacial roughness optimization
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Solution Overview
Problem
All-solid-state batteries face challenges in achieving optimal interfacial properties due to excessive interface roughness leading to side reactions, reduced reaction uniformity, and decreased durability, while insufficient roughness results in reduced interlayer adhesion and increased resistance.
Innovation Solution
The battery design includes a cathode active material layer, an anode active material layer, and a solid electrolyte layer with optimized surface roughness and current density, where the surface roughness of the cathode and anode active material layers are within specific ranges to enhance interfacial properties, and the use of a sulfide-based solid electrolyte with high lithium ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If surface roughness is increased to improve interlayer adhesion, then interlayer adhesion is improved, but side reactions increase and reaction uniformity decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the surface roughness parameters (Ra and Rz values) of the electrode layers. By establishing specific numerical ranges for roughness parameters, the invention transforms the qualitative relationship between roughness and adhesion into a quantifiable optimization problem, resolving the contradiction between improving adhesion through increased roughness while limiting side reactions through controlled roughness magnitude.
2Object-generated harmful factors
If surface roughness is decreased to reduce side reactions, then side reactions are suppressed, but interlayer adhesion is reduced and resistance increases
Solution Approach 1:
The patent resolves this contradiction by establishing minimum threshold values for surface roughness parameters. By defining that Ra and Rz must fall within specific ranges rather than simply being minimized, the invention ensures sufficient interlayer adhesion while preventing excessive roughness that would cause side reactions, thus balancing both requirements through parameter optimization.
3Strength
If surface roughness is increased to improve interlayer adhesion, then interlayer adhesion is improved, but resistance increases and durability decreases
Solution Approach 1:
The patent resolves this contradiction by establishing upper limit values for surface roughness parameters. By defining that Ra and Rz must not exceed specific thresholds, the invention prevents excessive roughness from causing increased resistance and durability issues, while still allowing sufficient roughness to maintain adequate interlayer adhesion, thus optimizing the balance between these competing requirements.
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 design improves interlayer adhesion, suppresses side reactions, and ensures reaction uniformity, leading to increased durability and efficiency of the all-solid-state battery.
Implementation Method 1
The anode active material layer of the all-solid-state battery includes a solid electrolyte conducting lithium ions
Data Source
AI summary
An all-solid-state battery comprises a cathode active material layer, an anode active material layer and a solid electrolyte layer interposed between the cathode active material layer and the anode active material layer, and wherein the all-solid-state battery satisfies Requirement 1 below,3<(b1+b2)/a[10−4·cm3/mA]<11, [Requirement 1]wherein, a indicates current density [mA/cm2] of the all-solid-state battery, b1 indicates surface roughness [μm] of one side of a cathode active material layer in a direction to a solid electrolyte layer, and b2 indicates surface roughness [μm] of one side of an anode active material layer in a direction to the solid electrolyte layer.