All-Solid-State Battery Electrode Active Material Impregnation
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Solution Overview
Problem
In all-solid-state batteries, the existing electrode active materials with secondary particles having primary particles aggregated together result in voids that prevent effective ion conduction, limiting the battery's energy density and capacity since the solid electrolyte fails to penetrate and utilize the interior of the electrode active material effectively.
Innovation Solution
The electrode active material is designed with secondary particles that have primary particles aggregated and impregnated with a solid electrolyte, forming an ion conduction path inside the particles, utilizing a method that involves preparing a mixture of electrode active material and solid electrolyte material, and performing heat pressing at a temperature of 60% or more of the solid electrolyte's melting point to ensure the electrolyte is impregnated within the voids of the secondary particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If secondary particles with aggregated primary particles are used as electrode active material, then the material structure is formed, but voids remain between primary particles that prevent effective ion conduction
Solution Approach 1:
The patent utilizes the porous structure created by aggregated primary particles within secondary particles. Instead of eliminating the voids, the invention impregnates the solid electrolyte into these voids, transforming the harmful porous structure into a beneficial ion conduction pathway. The solid electrolyte fills the spaces between primary particles, creating continuous ion conduction channels throughout the electrode active material.
Solution Approach 2:
The solid electrolyte acts as an intermediary substance that bridges the gap between primary particles. By impregnating the solid electrolyte into the voids between aggregated primary particles, it creates a conductive medium that enables ion transport through the previously non-conductive void spaces, resolving the ion conduction problem while maintaining the aggregated particle structure.
2Quantity of substance
If solid electrolyte is not impregnated into the interior of electrode active material, then manufacturing is simpler, but the interior of the material is not utilized and energy density is limited
Solution Approach 1:
The patent employs preliminary action by impregnating the solid electrolyte into the electrode active material during the manufacturing process, specifically during the heat pressing step. The solid electrolyte is introduced and impregnated into the voids between primary particles before the final electrode structure is formed, ensuring that the interior of the material is pre-filled with conductive pathways for optimal ion transport and energy utilization.
Solution Approach 2:
The patent utilizes parameter changes by controlling the heat pressing temperature and pressure conditions during manufacturing. By applying sufficient heat and pressure, the solid electrolyte material undergoes phase changes or becomes more pliable, enabling it to penetrate and impregnate into the voids between primary particles. This parameter control ensures thorough impregnation while maintaining the structural integrity of the aggregated particle system.
3Reliability
If heat pressing is performed at high temperature to impregnate solid electrolyte, then ion conduction is improved, but energy consumption and manufacturing complexity increase
Solution Approach 1:
The patent exploits phase transitions of the solid electrolyte material during heat pressing. By heating to a specific temperature range, the solid electrolyte undergoes a phase transition that increases its mobility or changes its physical state, enabling it to flow into and impregnate the voids between primary particles. This phase transition mechanism allows effective impregnation at relatively controlled temperatures rather than requiring excessively high heat input.
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 approach enhances ion conductivity and effectively utilizes the interior of the electrode active material, improving the battery's capacity and energy density by allowing ions and electrons to be exchanged both on the surface and within the electrode active material, thereby enhancing the overall battery characteristics.
Implementation Method 1
a region impregnated with the solid electrolyte in a gap between the plurality of primary particles
Implementation Method 2
performing heat pressing on a mixture of the material of the electrode active material and the solid electrolyte material at a temperature of 60% or more of a melting point of the solid electrolyte material
Data Source
AI summary
Positive electrode active material 2 is used for positive electrode layer 20 of all-solid-state battery 100, and contains plural secondary particles 2b in each of which plural primary particles 1a are aggregated. Plural of secondary particles 2b contain impregnation particles, the impregnation particles each being a secondary particle having a region impregnated with solid electrolyte 1 in a gap between plural primary particles 1a. The region impregnated with solid electrolyte 1 is a region in which solid electrolyte 1 is impregnated in a distance of 1 μm or more from an outer periphery of the impregnation particle toward an inside of the impregnation particle.