PTC Resistor Layer for Solid-State Battery Electrodes
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Solution Overview
Problem
Existing solid-state battery electrodes with PTC resistor layers face high electronic resistance at room temperature and inadequate performance due to high insulating inorganic substance content, which affects battery performance and safety during temperature increases.
Innovation Solution
A PTC resistor layer composed of a carbon-containing electroconductive material, an insulating inorganic substance, and a fluorine-containing polymer, with a specific hardness and carbon-to-fluorine atomic percentage ratio, is introduced between the electrode active material layer and the current collector to enhance flexibility and contact with the electrode active material layer, reducing electronic resistance at room temperature while maintaining high resistance at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a PTC resistor layer containing insulating inorganic substance is used, then high temperature resistance is improved, but electronic resistance at room temperature increases
Solution Approach 1:
The patent applies local quality by creating a PTC resistor layer with non-uniform composition: the surface layer (A layer) has high insulating inorganic substance content (50-90 mass%) for high temperature resistance, while the base layer (B layer) has lower insulating substance content (10-40 mass%) for better electronic conductivity at room temperature. This spatial variation in material composition resolves the contradiction between high temperature performance and room temperature conductivity.
Solution Approach 2:
The patent uses composite materials by combining three distinct components: insulating inorganic substance (e.g., alumina, silica), conductive material (e.g., carbon black, graphite), and polymer binder. The specific composite structure with two layers having different ratios of these materials enables simultaneous achievement of high temperature resistance (through the insulating layer) and acceptable room temperature conductivity (through the conductive network in the base layer).
2Stability of the object's composition
If insulating inorganic substance content is increased, then high temperature stability is improved, but contact with electrode active material layer deteriorates
Solution Approach 1:
The patent implements local quality by concentrating the insulating inorganic substance primarily in the A layer (surface layer) that contacts the electrode active material. The B layer (base layer) maintains lower insulating substance content and higher polymer content, providing flexibility and良好的 contact. This localized distribution allows high temperature stability where needed while preserving contact quality through the softer base layer.
Solution Approach 2:
The patent applies parameter changes by controlling the hardness of the PTC resistor layer surface to be 0.05-0.5 GPa through adjustment of polymer content and composition in the A layer. This hardness parameter optimization ensures the surface is soft enough to conform to the electrode active material surface for good contact, while the high insulating substance content provides thermal stability. The specific polymer types (e.g., polyvinylidene fluoride, polyacrylonitrile) are selected to achieve the desired mechanical properties.
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
The solution effectively suppresses the increase in electronic resistance at the interface between the PTC resistor layer and the electrode active material layer, thereby improving the performance and safety of solid-state batteries by maintaining excellent contact and followability, even under high temperature conditions.
Implementation Method 1
an electrode has been attempted, the electrode comprising a positive temperature coefficient (PTC) resistor layer which has electron conductivity at room temperature and which shows an increase in electronic resistance value with an increase in temperature
Data Source
AI summary
An electrode for solid-state batteries, comprising a PTC resistor layer, and a solid-state battery comprising the electrode. The electrode may be an electrode for solid-state batteries, wherein the electrode comprises an electrode active material layer, a current collector and a PTC resistor layer which is disposed between the electrode active material layer and the current collector and which is in contact with the electrode active material layer; wherein the PTC resistor layer contains a carbon-containing electroconductive material, an insulating inorganic substance and a fluorine-containing polymer.