All-solid-state battery electrode laminate surface roughness control
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Solution Overview
Problem
The challenge in manufacturing all-solid-state batteries is to prevent short-circuiting while reducing the thickness of the solid electrolyte layer, as excessive surface roughness of the active material layer leads to varying thickness and increased interface resistance, which can result in short-circuiting and higher internal resistance.
Innovation Solution
A method of manufacturing an electrode laminate with a surface roughness Ra value of 0.29 μm to 0.98 μm for the active material layer, achieved by applying a solid electrolyte layer-forming slurry and drying it, which reduces the thickness of the solid electrolyte layer and prevents short-circuiting, thereby lowering the internal resistance of the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the solid electrolyte layer is reduced to improve energy density, then the amount of active material can be increased, but short-circuiting becomes more likely due to damage in the thin solid electrolyte layer
Solution Approach 1:
The invention applies local quality by creating a dual-roughness structure: the cross-section view shows an irregular interface with protrusions and recesses for mechanical interlocking, while the top view maintains relative smoothness for uniform slurry application. This localized differentiation of surface properties allows the solid electrolyte layer to achieve both thin thickness and high adhesion strength, preventing short-circuiting while maximizing active material content.
2Reliability
If the surface of the active material layer is made excessively smooth to reduce interface resistance, then the interface resistance decreases, but the thickness of the solid electrolyte layer varies and short-circuiting occurs
Solution Approach 1:
The invention resolves this contradiction by implementing local quality through dual-roughness control: the cross-sectional roughness (Ra 0.3-3.0 μm) creates protrusions and recesses that ensure uniform solid electrolyte layer thickness and prevent short-circuiting, while the top surface roughness (Ra 0.03-0.3 μm) remains sufficiently smooth to maintain low interface resistance for ion transport.
3Quantity of substance
If the thickness of the solid electrolyte layer is reduced to improve energy density, then the internal resistance decreases, but the manufacturing precision required increases to prevent short-circuiting
Solution Approach 1:
The invention applies preliminary action by pre-forming the active material layer with specific dual-roughness characteristics before applying the solid electrolyte layer. The cross-sectional roughness is established in advance to create mechanical interlocking features, ensuring that even when the solid electrolyte layer is applied thinly, it adheres strongly and uniformly without short-circuiting, thereby enabling high energy density with controlled manufacturing precision.
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 effectively prevents short-circuiting and reduces internal resistance by maintaining a controlled surface roughness of the active material layer, allowing for a thinner solid electrolyte layer and improved energy density in all-solid-state batteries.
Implementation Method 1
forming a solid electrolyte layer on the active material layer by applying a solid electrolyte layer-forming slurry to the active material layer and drying the solid electrolyte layer-forming slurry
Data Source
AI summary
A method of manufacturing an electrode laminate, which includes an active material layer and a solid electrolyte layer formed on the active material layer, includes: an active material layer forming step of forming an active material layer; and a solid electrolyte layer forming step of forming a solid electrolyte layer on the active material layer by applying a solid electrolyte layer-forming slurry to the active material layer and drying the solid electrolyte layer-forming slurry. In this method, a surface roughness Ra value of the active material layer is 0.29 μm to 0.98 μm when calculated using a laser microscope.