All Solid State Battery Co-Firing Process
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Solution Overview
Problem
Existing all solid state secondary batteries face challenges in mass production due to slow film-formation rates and high manufacturing costs, particularly in producing thin-film lithium ion batteries, which are not industrially viable for high-power applications.
Innovation Solution
An all solid state secondary battery is developed using a laminated material with positive and negative electrode units alternately layered through an ion-conductive inorganic material, where the layers are subjected to co-firing at 900 to 1100°C, utilizing metals like Ag, Pd, or Au, or their alloys, and calcined powders for the active and ion-conductive materials, allowing for efficient production and improved charge-discharge characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thin-film solid secondary batteries are produced by sputtering method, then film quality and battery characteristics are improved, but film-formation rate becomes extremely slow and manufacturing cost increases
Solution Approach 1:
The patent replaces the sputtering method (physical vapor deposition) with a co-firing process that uses calcined powders and paste application. This substitution transitions from a slow physical deposition process to a faster chemical sintering process, achieving both acceptable film quality and significantly improved production speed suitable for industrial manufacturing.
Solution Approach 2:
The patent changes the processing parameters by using calcined powders with controlled particle sizes and specific surface areas, applying pastes with optimized compositions, and controlling co-firing temperature and atmosphere. These parameter changes enable rapid formation of high-quality thin films without the slow deposition rates inherent in sputtering methods.
2Reliability
If thin-film solid secondary batteries are produced by sputtering method, then battery characteristics are improved, but manufacturing cost increases
Solution Approach 1:
The patent employs calcined powders and paste materials that can be applied rapidly and processed in batch co-firing operations. These materials are more cost-effective than the expensive vacuum equipment and slow deposition processes required for sputtering, enabling economical production while maintaining battery performance.
Solution Approach 2:
The patent performs preliminary calcination of powders before the co-firing process, preparing the materials in advance with optimal properties. This preliminary action ensures that the main co-firing process proceeds rapidly and efficiently, reducing overall manufacturing time and cost while producing high-quality batteries.
3Shape
If multi-layered structure is created by symmetric lamination, then battery structure is achieved, but industrial practicality decreases
Solution Approach 1:
The patent divides the battery structure into modular units with positive electrode units and negative electrode units that can be independently prepared and then assembled. This segmentation allows for standardized production of individual units that can be rapidly stacked and co-fired together, greatly improving industrial practicality compared to attempting to form complex multi-layered structures in a single symmetric lamination process.
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 method enables the production of batteries with excellent charge-discharge characteristics, reduced internal resistance, and good energy efficiency, making them suitable for industrial applications with lower manufacturing costs and faster production times.
Implementation Method 1
the laminated material is a product subjected to co-firing
Implementation Method 2
a positive-electrode unit and a negative-electrode unit are alternately laminated through an ion-conductive inorganic-material layer
Data Source
AI summary
This is to provide an all solid state secondary battery which can be produced by an industrially employable method capable of mass-production and has excellent secondary battery characteristics. This is an all solid state secondary battery containing a laminated material in which a positive-electrode unit and a negative-electrode unit are laminated alternately through an ion conductive inorganic-material layer, the positive-electrode unit has positive active material layers on both surfaces of a positive-electrode collector layer, the above-mentioned negative-electrode unit has negative active material layers on both surfaces of a negative-electrode collector layer, (A) at least one of the positive-electrode collector layer and the negative-electrode collector layer comprises a metal of either of Ag, Pd, Au and Pt, or an alloy containing either of Ag, Pd, Au and Pt, or a mixture containing two or more kinds selected from the metals and alloys, (B) each layer is in a sintered state, or (C) at least the starting material for the ion conductive inorganic material of the ion conductive inorganic-material layer is a calcined powder.