Multi-Frequency Induction Drying for Battery Electrode Coatings
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Solution Overview
Problem
Existing secondary battery manufacturing processes face challenges in quickly and evenly drying the coated portions of electrode sheets, which can lead to defects such as dry film formation and quality deterioration.
Innovation Solution
A drying apparatus utilizing a combination of induction heating and wavelength drying methods, including a multi-coil induction heating unit with different frequencies and a switch portion, along with microwave and laser drying units, to selectively apply current and heat the coated and non-coated portions of the electrode sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional drying methods are used, then the drying process is simple, but the drying time is long and drying quality is poor
Solution Approach 1:
The drying apparatus divides the electrode sheet into coated portions and non-coated portions, and applies different heating strategies to each. The induction heating unit specifically targets the coated portions containing solvent, enabling selective and efficient drying without overheating the non-coated portions, thus reducing overall drying time while maintaining quality
Solution Approach 2:
The patent replaces conventional thermal conduction heating with electromagnetic induction heating. The induction heating unit generates eddy currents directly in the coated portions of the electrode sheet, converting electromagnetic energy into heat internally within the target areas. This substitution enables rapid and localized drying, significantly reducing drying time compared to traditional external heating methods
2Productivity
If high temperature drying is applied to dry coated portions quickly, then drying speed increases, but dry film formation occurs on the surface
Solution Approach 1:
The drying apparatus applies different heating methods to different regions: induction heating is applied specifically to the coated portions where solvent removal is needed, while the non-coated portions are either excluded from heating or receive minimal heat. This localized heating approach enables rapid drying of coated areas without causing surface dry film formation, maintaining manufacturing precision while improving drying speed
Solution Approach 2:
The induction heating unit acts as an intermediary that selectively couples with the coated portions containing conductive materials or magnetic particles. This intermediary mechanism enables controlled internal heating of only the coated areas, preventing excessive surface temperature rise and dry film formation while still achieving rapid solvent evaporation
3Manufacturing precision
If uniform heating is applied to the entire electrode sheet, then heating is simple, but the coated portions are not dried evenly
Solution Approach 1:
The heating system is designed with spatially varying heating characteristics: the induction heating unit is positioned and configured to concentrate electromagnetic energy specifically on the coated portions. This creates a non-uniform heating field that is optimally distributed - intense where needed (coated portions) and minimal where not needed (non-coated portions), achieving perfect drying uniformity without requiring complex multi-zone control systems
4Productivity
If multiple heating frequencies are used to optimize drying, then drying effectiveness improves, but the control system becomes more complex
Solution Approach 1:
The drying apparatus incorporates a switchable multi-frequency induction heating system that can dynamically select between different operating frequencies (e.g., 20 kHz and 60 kHz) based on the specific requirements of the electrode sheet being processed. This dynamic adaptability allows optimization of heating penetration and efficiency for different material compositions and thicknesses, improving drying effectiveness while the switching mechanism keeps control complexity manageable
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 apparatus effectively minimizes dry film formation and reduces drying time, ensuring high-quality electrode sheet production by evenly heating the coated portions from the inside, thereby improving the manufacturing process efficiency.
Implementation Method 1
an induction heating unit disposed to face the electrode sheet and drying the coated portion through electromagnetic induction
Implementation Method 2
a microwave drying portion irradiating a microwave to the electrode sheet
Implementation Method 3
a laser drying portion irradiating a laser to the electrode sheet
Data Source
AI summary
A drying apparatus for secondary battery, wherein the drying apparatus dries an electrode sheet including an electrode current collector, a coated portion on which an electrode active material is applied on at least one surface of the electrode current collector, and a non-coated portion on which the electrode active material is not applied, wherein the coated portion is disposed to be parallel to a first direction to form at least one electrode line, includes an induction heating unit disposed to face the electrode sheet and drying the coated portion through electromagnetic induction, wherein the induction heating unit includes a multi-coil portion including a plurality of coils having different heating frequencies; and a switch portion provided to selectively apply current to any one of the plurality of coils.