PTC Resistor Layer Surface Roughness for Solid-State Battery Electrodes
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Solution Overview
Problem
Existing solid-state battery electrodes with PTC resistor layers containing insulating inorganic substances face high electronic resistance at room temperature and inadequate performance due to poor contact between the PTC resistor layer and the electrode active material layer, while those without insulating inorganic substances experience decreased resistance at high temperatures, failing to effectively manage temperature-related issues.
Innovation Solution
Incorporating a PTC resistor layer with a surface roughness of 1.1 μm or less, composed of electroconductive material, insulating inorganic substance, and polymer, to enhance contact and followability with the electrode active material layer, thereby maintaining low electronic resistance at room temperature and 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 management is improved, but electronic resistance at room temperature increases
Solution Approach 1:
The patent controls the surface roughness parameter of the PTC resistor layer to be 1.1 μm or less, which optimizes the contact interface with the electrode active material layer. This parameter control allows the layer to maintain low electronic resistance at room temperature while preserving the high temperature resistance management capability provided by the insulating inorganic substance.
Solution Approach 2:
The PTC resistor layer is formulated as a composite material containing electroconductive material, insulating inorganic substance, and polymer in specific proportions. This composite structure enables simultaneous achievement of low room temperature resistance (through electroconductive material) and high temperature resistance management (through insulating inorganic substance), resolving the contradiction between the two opposing requirements.
2Temperature
If the PTC resistor layer contains insulating inorganic substance, then temperature management capability is improved, but contact with electrode active material layer deteriorates
Solution Approach 1:
The patent specifies that the surface roughness of the PTC resistor layer must be 1.1 μm or less to ensure proper contact with the electrode active material layer. This parameter specification resolves the contradiction by controlling the surface morphology to maintain good interfacial contact while retaining the temperature management functionality provided by the insulating inorganic substance within the layer composition.
Solution Approach 2:
The patent applies the principle of local quality by ensuring that the surface of the PTC resistor layer has different properties from its bulk composition. The surface is controlled to have low roughness (1.1 μm or less) for optimal contact, while the bulk contains the insulating inorganic substance for temperature management, thus resolving the contradiction between contact quality and temperature management capability.
3Reliability
If PTC resistor layer without insulating inorganic substance is used, then room temperature electronic resistance is reduced, but high temperature resistance stability deteriorates
Solution Approach 1:
The patent formulates the PTC resistor layer as a composite material containing both electroconductive material (for low room temperature resistance) and insulating inorganic substance (for high temperature resistance stability). The specific composition ratio and surface roughness control enable the composite to simultaneously achieve low room temperature resistance and maintain resistance stability at high temperatures, resolving the contradiction between these two opposing 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 configuration suppresses the increase in electronic resistance at the interface between the PTC resistor layer and the electrode active material layer, maintaining battery performance and preventing adverse temperature effects, such as those from short circuits or overcharging.
Implementation Method 1
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 an electroconductive material, an insulating inorganic substance and a polymer; and wherein a surface roughness Ra of an electrode active material layer-contacting surface of the PTC resistor layer, is 1.1 μm or less.