All Solid State Battery Anode Hardness and Confining Pressure
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Solution Overview
Problem
Existing all solid state batteries face challenges in achieving improved charging characteristics at high rates due to insufficient control over confining pressure, voidage, orientation, and hardness of the anode active material layer, leading to deteriorated input characteristics.
Innovation Solution
Incorporating graphite as the anode active material with a hardness of 0.36 GPa or more and a sulfide solid electrolyte, and confining the battery element at a pressure of more than 75 kgf/cm2, while maintaining a voidage of 30% or less, to optimize the anode active material layer's structure and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the anode active material layer uses conventional graphite with insufficient hardness control and the battery element is not confined at adequate pressure, then the structure is simple and easy to manufacture, but the input characteristics during high rate charging deteriorate
Solution Approach 1:
The invention specifies precise parameter ranges: graphite hardness of 0.36 GPa or more (measured by nanoindentation), confining pressure of more than 75 kgf/cm2, and voidage of 30% or less. These parameter changes transform the anode material properties to enable high rate charging while maintaining manufacturing feasibility through clear specification limits.
Solution Approach 2:
The invention applies confining pressure of more than 75 kgf/cm2 during the battery assembly process to preliminarily compress the anode active material layer, reducing voidage to 30% or less and improving particle orientation before the battery enters service. This preliminary action ensures optimal charging characteristics are achieved from the outset.
2Reliability
If the graphite anode material has insufficient hardness (below 0.36 GPa), then the material is softer and easier to process, but the ion and electron conduction paths become insecure during high rate charging
Solution Approach 1:
The invention establishes a minimum hardness threshold of 0.36 GPa for graphite anode material, measured by nanoindentation. This parameter change ensures the graphite maintains sufficient structural integrity to secure ion and electron conduction paths during high rate charging, while still being processable through standard manufacturing techniques.
3Productivity
If the battery element is not confined at adequate pressure (less than 75 kgf/cm2), then the device complexity is reduced and manufacturing is simpler, but the voidage of the anode active material layer increases and charging performance deteriorates
Solution Approach 1:
The invention applies confining pressure of more than 75 kgf/cm2 during battery assembly to preliminarily compress the anode active material layer, reducing voidage to 30% or less. This preliminary compression action ensures optimal particle orientation and density are achieved before the battery enters service, improving high rate charging performance.
Solution Approach 2:
The invention specifies a minimum confining pressure of 75 kgf/cm2 as a critical parameter for battery assembly. This parameter change transforms the compression process from a simple mechanical step to a controlled process that optimizes anode material structure, enabling high rate charging while using standard battery assembly equipment.
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 enhances the battery's input characteristics during high rate charging, ensuring secure ion and electron conduction paths and maintaining the graphite's structure, resulting in an all solid state battery suitable for high rate charging.
Implementation Method 1
a solid electrolyte layer formed between the cathode active material layer and the anode active material layer
Implementation Method 2
the anode active material layer contains graphite as an anode active material
Data Source
AI summary
The main object of the present invention is to provide an all solid state battery suitable for high rate charging. The present invention solves the problem by providing an all solid state battery including a battery element having a cathode active material layer, an anode active material layer, and a solid electrolyte layer formed between the cathode active material layer and the anode active material layer, characterized in that the anode active material layer contains graphite as an anode active material and a sulfide solid electrolyte, the graphite has a hardness of 0.36 GPa or more by a nanoindentation method, and the battery element is confined at a pressure more than 75 kgf/cm2.