Sintered Cathode Material Bricks for Saggar-Free Calcination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The calcination process for metal oxide cathode materials in lithium ion batteries is inefficient due to high capital and operating costs, energy consumption, and inefficiencies introduced by the use of saggars, which affect heat and mass transfer, productivity, and the quality of the active material.
Innovation Solution
A self-standing calcined element is formed by compressing a mixture of lithium and metal powders into geometric shapes like bricks or tiles, which are then heated in a high-temperature furnace, eliminating the need for saggars and improving thermal conductivity and uniformity, thereby increasing throughput and reducing residence time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If saggars are used to hold cathode precursor powder during calcination, then the powder can be contained and processed, but heat and mass transfer coefficients are low and residence time increases
Solution Approach 1:
The patent removes the saggars (ceramic crucibles) from the calcination process entirely. Instead of holding powder in containers, the precursor mixture is directly calcined in the kiln without intermediate containment vessels, eliminating the heat and mass transfer barriers that saggars create.
Solution Approach 2:
The patent uses a porous plug made of ceramic material to support the precursor powder during calcination. This porous structure allows for significantly improved heat and mass transfer compared to solid saggars, while still providing necessary support for the powder mixture.
2Productivity
If saggars are stacked in parallel to increase productivity, then throughput increases, but the configuration is not scalable and handling complexity increases
Solution Approach 1:
By removing saggars from the process, the patent eliminates the need for complex saggar handling, stacking, and inspection systems. The precursor powder is directly calcined in the kiln, simplifying the entire handling system while maintaining or improving throughput.
3Reliability
If saggars are used for calcination, then powder can be processed, but cool down times are extended to prevent saggar cracking
Solution Approach 1:
The patent eliminates saggars from the process, removing the constraint of saggar thermal shock resistance. Without saggars to protect from cracking, the calcination process can proceed with optimized heating and cooling rates, significantly reducing total processing time.
4Manufacturing precision
If saggars are replaced frequently to maintain quality, then material quality is maintained, but consumable costs increase
Solution Approach 1:
The patent removes saggars from the process entirely, eliminating the recurring cost of saggar replacement. The porous plug design allows for direct calcination without expensive ceramic crucibles that need frequent replacement.
Solution Approach 2:
The patent uses a disposable porous plug that is inexpensive compared to traditional saggars. This cheap support structure is replaced after single use, but at much lower cost than the expensive ceramic saggars it replaces.
5Productivity
If powder is filled densely in saggars to increase loading, then productivity increases, but gas diffusion and thermal distribution are affected causing quality issues
Solution Approach 1:
The porous plug structure provides excellent gas diffusion pathways while supporting high powder loading. The porous structure allows thermal and mass transfer to penetrate deep into the powder bed, maintaining uniform heating and reaction even at high loading densities.
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 the crystallinity of the cathode active material, increases volumetric efficiency, reduces thermal mass, and lowers consumable costs, while maintaining the structural integrity of the calcined elements, thus improving the overall efficiency and cost-effectiveness of the manufacturing process.
Implementation Method 1
heating the self-standing precursor element to form a self-standing calcined element comprising a cathode active material
Implementation Method 2
calcination of metal oxide cathode active materials typically involves baking materials in powder form through large roller hearth kilns at high-temperatures to achieve target material properties
Data Source
AI summary
Disclosed are self-standing calcined elements (e.g. bricks and tiles) comprising a cathode active material, and methods of preparation thereof. The process includes mixing a reagent with a metal precursor to form a precursor mixture, compressing the precursor mixture into a self-standing precursor element (e.g. brick and tile), and heating the self-standing precursor element (e.g. brick and tile) to form a self-standing calcined element (e.g. brick and tile) comprising a cathode active material.