Positive Electrode Layer Densification Without Conductivity Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high pressure pressing used to increase the filling rate of the positive electrode layer in all-solid-state batteries leads to increased porosity and decreased conductivity of the active material, limiting the effective use of the positive electrode layer and battery characteristics.
Innovation Solution
A positive electrode layer with a filling rate of 85% or more and porosity of 5% or less, utilizing spherical particles with an aspect ratio of 1.6 or less and a sulfide-based or halide-based solid electrolyte, which is softened during the manufacturing process to prevent void enlargement and enhance filling, thereby maintaining high conductivity and improving battery capacity and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high pressure pressing is applied to increase the filling rate of the positive electrode layer, then the filling rate increases, but the porosity of the active material increases and conductivity decreases
Solution Approach 1:
The patent changes the physical-chemical parameters of the solid electrolyte by controlling its softening point to be within a specific range (80-150°C). This parameter change allows the electrolyte to soften during pressing, enabling it to fill voids and prevent porosity increase, thus resolving the contradiction between filling rate and conductivity
Solution Approach 2:
The patent utilizes the phase transition of the solid electrolyte from solid to softened state during the pressing process. The electrolyte softens at controlled temperatures, flows into voids between active material particles, and then re-solidifies, effectively filling pores without increasing porosity while maintaining high filling rate and conductivity
2Quantity of substance
If high pressure pressing is applied to increase the filling rate, then the filling rate increases, but the effective use of the positive electrode layer is limited
Solution Approach 1:
By optimizing the softening point parameter of the solid electrolyte to within 80-150°C, the patent enables the electrolyte to become pliable during pressing, effectively filling voids and ensuring good contact between active material particles and electrolyte. This maximizes the effective use of the electrode layer while achieving high filling rates
3Quantity of substance
If high pressure pressing is applied to increase the filling rate, then the filling rate increases, but the battery characteristics are limited
Solution Approach 1:
The patent optimizes the softening point parameter of the solid electrolyte to a specific range (80-150°C) that balances multiple requirements: softening enough to fill voids during pressing, maintaining structural integrity, and ensuring good interfacial contact. This parameter optimization enables high filling rates while maintaining excellent battery characteristics including capacity, energy density, and cycle stability
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 increases the energy density and battery capacity of all-solid-state batteries by maintaining high conductivity and preventing porosity increase in the positive electrode active material, leading to improved battery characteristics.
Implementation Method 1
a sulfide-based or halide-based solid electrolyte, which is softened during the manufacturing process to prevent void enlargement and enhance filling
Data Source
AI summary
Positive electrode layer 20 is used for an all-solid-state battery. Positive electrode layer 20 includes positive electrode active material 2 and solid electrolyte 1. A filling rate of positive electrode layer 20 is 85% or more. A porosity of positive electrode active material 2 is 5% or less.