Nonaqueous Battery Electrode Drying and Cooling Process
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Solution Overview
Problem
The existing method for producing nonaqueous electrolyte secondary battery electrodes often results in wrinkles due to natural cooling, which affects the quality of the electrodes.
Innovation Solution
A method involving the application of an active material slurry to a core, followed by controlled drying with hot air and subsequent cooling with lower-temperature air to prevent warping and wrinkling, ensuring the electrode is kept aloft during the cooling process to maintain a temperature of 40° C. or lower.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If natural cooling is used after drying, then the process is simple, but wrinkles form in the uncovered portions of the electrode
Solution Approach 1:
The invention changes the cooling parameters from natural cooling to controlled cooling with specific temperature thresholds. The core is cooled to 40°C or lower before winding, preventing thermal stress and wrinkles while maintaining process simplicity through automated temperature control.
Solution Approach 2:
The invention implements temperature monitoring and feedback control during the cooling process. The core is kept aloft and cooled until a specific temperature (40°C or lower) is reached, ensuring precise control to prevent wrinkles while maintaining operational simplicity.
2Productivity
If the core is wound immediately after drying, then productivity is high, but warping and wrinkles occur due to residual heat
Solution Approach 1:
The invention performs preliminary cooling action before winding by keeping the core aloft and cooling it to 40°C or lower. This preliminary temperature reduction prevents warping during winding while maintaining high productivity through automated continuous processing.
Solution Approach 2:
The invention replaces mechanical winding immediately after drying with a controlled cooling process first. The core is cooled using air flow while kept aloft, then wound only after reaching the appropriate temperature, eliminating wrinkles without significantly reducing productivity.
3Quantity of substance
If hot air drying is applied, then the active material slurry is effectively dried, but the core becomes too hot and causes wrinkling upon cooling
Solution Approach 1:
The invention uses periodic or staged air flow action, first applying hot air for drying, then switching to cooling air flow. This periodic action effectively removes moisture while controlling temperature to prevent wrinkling during the transition from drying to cooling.
Solution Approach 2:
The invention uses air flow as an intermediary medium to transfer heat during drying and then remove heat during cooling. By controlling the air flow temperature and direction, the core is effectively dried and then cooled to appropriate levels without causing thermal stress and wrinkles.
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 effectively suppresses wrinkling in the electrodes, enhancing the production quality of nonaqueous electrolyte secondary batteries by maintaining the electrode's flatness and preventing warping.
Implementation Method 1
a drying step of blowing first hot air to the core from at least a lower side in a vertical direction while keeping the core aloft
Implementation Method 2
a cooling step of blowing first cooling air having a lower temperature than the first hot air from at least the lower side in the vertical direction while keeping the core aloft so as to cool the core until the core has a temperature of 40° C. or lower
Data Source
AI summary
A negative electrode active material slurry is applied to one surface of a strip-shaped negative electrode core so as to form multiple lines of the negative electrode active material slurry, the lines extending in an X direction and being spaced from each other in a Y direction. Subsequently, while keeping the negative electrode core aloft, first hot air is blown toward the negative electrode core from at least a lower side in a vertical direction, and then, while keeping the negative electrode core aloft, first cooling air having a lower temperature than the first hot air is blown toward the negative electrode core from at least the lower side in the vertical direction so as to decrease the temperature of the negative electrode core to 40° C. or lower.