Solid-State Battery Anode Coating for Short-Circuit Heat Reduction
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Solution Overview
Problem
In all solid state batteries, the calorific value tends to increase during short circuits due to the absence of a separating layer with current-shutting function, and simply arranging a resistance layer does not sufficiently reduce the calorific value without increasing internal short circuits.
Innovation Solution
An all solid state battery is designed with an anode current collector that includes a coating layer containing an oxide active material and a conductive material, where the ratio of the coating layer thickness to the anode active material layer thickness is less than 20%, and the proportion of the conductive material in the coating layer is between 0.1 weight % and 0.5 weight %.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a resistance layer is arranged between anode mixture layer and anode current collector to secure insulation during internal circuit, then the calorific value cannot be sufficiently reduced, but the internal short circuit increases
Solution Approach 1:
The coating layer is formed as a composite material containing both oxide active material particles and conductive material particles. The oxide active material provides insulation during internal short circuits, while the conductive material maintains electron conductivity for normal battery operation. This composite structure resolves the contradiction by combining materials with opposing electrical properties to achieve both safety and functionality.
Solution Approach 2:
The invention controls specific parameters of the coating layer: the thickness ratio T1/T2 is set to 0.05 or more and 0.20 or less, and the conductive material content is set to 0.1 wt% or more and 1.0 wt% or less. By optimizing these parameters, the coating layer achieves the right balance between providing insulation during short circuits and maintaining sufficient electron conductivity for normal operation, thus reducing calorific value without increasing internal short circuits.
2Object-affected harmful factors
If a coating layer with oxide active material is arranged on anode current collector to reduce calorific value, then the calorific value can be reduced, but the electron conductivity path may be insufficient
Solution Approach 1:
The coating layer combines oxide active material particles with conductive material particles to create a composite structure that simultaneously provides insulation during short circuits and maintains electron conductivity during normal operation. The conductive material fills the spaces between oxide particles and forms conductive networks, ensuring sufficient electron transport while the oxide particles provide thermal insulation during abnormal conditions.
Solution Approach 2:
The coating layer exhibits different local properties: regions with higher oxide active material content provide insulation and calorific value reduction, while regions with conductive material provide electron conductivity pathways. This spatial distribution of different material properties within the same layer allows the system to achieve both functions simultaneously without compromising electron transport.
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 effectively reduces the calorific value while preventing an increase in internal short circuits, by forming an electron conducting path that maintains battery characteristics and utilizes the oxide active material's conductivity changes to shut down the path during short circuits.
Implementation Method 1
utilizes the oxide active material's conductivity changes to shut down the path during short circuits
Data Source
AI summary
A main object of the present disclosure is to provide an all solid state battery of which calorific value can be reduced while preventing internal short circuit from increasing. The present disclosure achieves the object by providing an all solid state battery comprising an anode active material layer and an anode current collector; wherein the anode current collector includes a coating layer containing an oxide active material and a conductive material, on a surface of the anode active material layer side; a ratio of a thickness of the coating layer with respect to a thickness of the anode active material layer is less than 20%; and a proportion of the conductive material in the coating layer is more than 0 weight % and less than 1.0 weight %.