Ceramic Green Tape Casting for Crack-Free Battery Sintering
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Solution Overview
Problem
Solid state ion conducting ceramics face issues during the formation and sintering of thin films, such as sticking to substrates, cracking, warping, and brittleness, which hinder the production of high-density green tapes suitable for electrochemical devices.
Innovation Solution
A process involving the preparation of a slurry with source powder, mixing with a binder in a non-reactive environment, casting, and drying to achieve a high-density green tape, followed by sintering, all under controlled conditions to prevent cracking and warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to form thin films of solid state ion conducting ceramics, then the films can be produced, but they tend to stick to substrates, crack, warp, or become brittle during sintering
Solution Approach 1:
The patent applies parameter changes by optimizing the slurry composition (viscosity, solid content, binder ratio) and processing parameters (drying temperature, sintering temperature, atmosphere control) to achieve high-density green tapes that sinter without cracking or warping. The slurry viscosity is specifically controlled to balance flowability for uniform coating with sufficient structure to prevent substrate sticking.
Solution Approach 2:
The patent uses composite materials by formulating a slurry containing ceramic precursor particles, organic binders, and dispersants that work together to create green tapes with improved sintering behavior. The binder system provides mechanical strength during handling while the dispersant ensures uniform particle distribution, preventing defects during sintering.
2Quantity of substance
If high density is achieved in green tapes, then volumetric and gravimetric energy densities improve, but the films become more prone to cracking and warping during sintering
Solution Approach 1:
The patent applies preliminary action by preparing high-density green tapes with optimized composition and structure before sintering, including controlling particle size distribution and binder content, so that the tapes have the necessary mechanical strength to withstand the sintering process without cracking or warping.
Solution Approach 2:
The patent uses beforehand cushioning by incorporating organic binders and controlling the green tape density to provide a buffer against thermal stress during sintering, allowing the high-density structure to be maintained without catastrophic failure from cracking or warping.
3Manufacturing precision
If the green tape is made with high ceramic loading, then the final sintered film has high density, but the tape becomes too brittle to handle and manipulate
Solution Approach 1:
The patent applies parameter changes by optimizing the binder-to-ceramic ratio and controlling the plasticizer content to maintain adequate flexibility and handleability in high-ceramic-loading green tapes, enabling them to be manipulated without breaking while still achieving high density after sintering.
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 process results in high-density green tapes that can be sintered without warping or cracking, suitable for direct incorporation into electrochemical devices without further processing, enhancing their suitability for electrochemical applications.
Implementation Method 1
mixing the slurry with a binder solution in a non-reactive environment
Implementation Method 2
drying the green tape in a non-reactive environment to achieve density >2.9 g/ml
Implementation Method 3
the at least one source powder is calcined in a non-reactive environment to achieve density >4.7 g/ml as measured by geometric density
Implementation Method 4
these films tend to crack, warp, or otherwise have surface deteriorations during sintering
Data Source
AI summary
Set forth herein are processes and materials for making ceramic thin green tapes by casting ceramic source powders and precursor reactants, binders, and functional additives into unsintered thin green tapes in a non-reactive environment.