Sagger Notch Design for CO2 Discharge in Battery Material Firing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sagger designs for firing secondary battery active materials fail to efficiently distribute atmospheric gases and discharge carbon dioxide by-products, leading to reduced battery performance due to lithium carbonate formation and decreased capacity.
Innovation Solution
A sagger with a notch portion on its side wall, occupying 30% to 70% of the wall area, and a rounded edge at the bottom, along with a through-hole on the lower surface, allows for uniform gas distribution and discharge of carbon dioxide, using materials like mullite, cordierite, or zircon, and employing a method involving loading raw materials in a firing furnace and cooling to produce a secondary battery active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If carbon dioxide is not discharged from the sagger during firing, then the firing process can be simplified, but lithium carbonate forms on the active material surface reducing battery capacity
Solution Approach 1:
The sagger side wall is segmented by introducing a notch portion that divides the wall into multiple sections. This segmentation creates a dedicated gas discharge pathway without complicating the overall firing process, allowing CO2 to escape while maintaining manufacturing simplicity
Solution Approach 2:
The notch portion acts as an intermediary structure between the sagger interior and exterior. It provides a controlled interface for gas exchange, enabling CO2 discharge while protecting the overall firing process from complexity
2Ease of manufacture
If atmospheric gas is not distributed uniformly in the sagger, then the firing process can be simpler, but the active material exhibits uneven firing quality
Solution Approach 1:
The side wall is divided into multiple sections by the notch portion, creating multiple gas entry/exit points. This segmentation enables atmospheric gas to distribute more uniformly throughout the sagger interior, improving firing quality without adding process complexity
Solution Approach 2:
The notch portion introduces a new dimensional feature on the side wall surface. This dimensional change creates additional gas flow pathways that enhance atmospheric gas distribution throughout the three-dimensional space inside the sagger
3Ease of manufacture
If the sagger edge is sharp rather than rounded, then manufacturing the sagger is easier, but gas flow and by-product discharge are hindered
Solution Approach 1:
The lower edge of the sagger side wall is designed with a rounded portion instead of a sharp edge. This curvature facilitates smoother gas flow along the wall and improves the discharge of by-products from the sagger interior, enhancing productivity while remaining manufacturable
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 design ensures uniform firing quality, reduces residual lithium concentration, improves slurry dispersibility, and enhances battery capacity by effectively managing gas flow and by-product discharge during the firing process.
Implementation Method 1
a notch portion that is recessed from an upper portion of a side wall thereof to open a portion of the side wall, wherein a ratio of an area of the notch portion to an area of the side wall is 30% to 70%
Implementation Method 2
carbon dioxide remaining in the sagger may react with lithium oxide on the surface of the positive electrode active material to form lithium carbonate
Data Source
AI summary
A sagger for firing an object to be fired includes an active material for a secondary battery. Carbon dioxide that is a reaction by-product produced during a positive electrode active material firing process can be smoothly discharged from the sagger, and such a smooth discharge of carbon dioxide can lower a residual lithium concentration of a positive electrode active material and thus can improve dispersibility of a positive electrode active material slurry and also improve capacity of a battery.