Dual Solid Electrolyte Layers for Low-Resistance Solid-State Batteries
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Solution Overview
Problem
Existing all-solid-state batteries face issues with increased resistance and a high risk of short circuits due to lithium dendrite growth at the negative electrode, primarily caused by the use of binders in the solid electrolyte layers, which limit lithium mobility and increase the contact area between the solid electrolyte and the negative electrode.
Innovation Solution
The battery design incorporates a first solid electrolyte layer with a binder and a second solid electrolyte layer without a binder, ensuring direct contact between the second layer and the negative electrode, thereby increasing the contact area and preventing lithium plating and dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a binder is included in the solid electrolyte layer to bind solid electrolyte particles, then the structural integrity of the solid electrolyte layer is improved, but lithium mobility is reduced and resistance is increased
Solution Approach 1:
The solid electrolyte layer is divided into multiple layers with different binder contents. The first solid electrolyte layer contains a binder for structural integrity, while the second solid electrolyte layer has reduced or no binder for optimal lithium mobility. This segmentation allows each layer to perform its specialized function without compromise.
Solution Approach 2:
Different regions of the solid electrolyte layer are assigned different binder concentrations based on local requirements. The region closer to the positive electrode uses more binder for structural support, while the region closer to the negative electrode uses less binder to facilitate lithium ion transport, creating local quality variations that optimize overall performance.
2Reliability
If the contact area between the solid electrolyte layer and the negative electrode is increased to prevent lithium dendrite growth, then safety is improved, but the thickness of the solid electrolyte layer must be reduced which may increase resistance
Solution Approach 1:
The solid electrolyte layer is segmented into multiple thin layers rather than one thick layer. This allows the total thickness to be reduced for better contact with the negative electrode, while each individual layer maintains sufficient integrity. The cumulative effect of multiple layers provides both safety and low resistance.
Solution Approach 2:
The solid electrolyte layer is constructed as a composite structure with at least two different solid electrolyte materials having different properties. One material provides structural stability with higher binder content, while another material optimized for lithium conductivity has lower binder content. This composite approach enables simultaneous achievement of safety and low resistance.
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 reduces the risk of short circuits and enhances lithium mobility, improving the safety and reducing resistance in the all-solid-state battery.
Implementation Method 1
Lithium that has moved to the negative electrode 140 through the solid electrolyte particles 110 is plated on the surface of the negative electrode 140
Implementation Method 2
the solid electrolyte layer 120 is configured such that solid electrolyte particles 110 are bound with each other by a binder 130
Data Source
Figure 1~2
AI summary
The present invention relates to an all-solid-state battery including a positive electrode, a negative electrode, and a solid electrolyte interposed between the positive electrode and the negative electrode, wherein the solid electrolyte is constituted by a first solid electrolyte layer including a binder and a second solid electrolyte layer not including a binder, and the second solid electrolyte layer faces the negative electrode, whereby safety of the all-solid-state battery is improved while resistance of the all-solid-state battery is low.