Lithium-Ion Electrode Foil Cooling for Layer Thickness Control
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Solution Overview
Problem
Existing manufacturing methods for sheet-shaped electrodes in lithium-ion batteries face challenges in maintaining the thickness of the active material layer when producing electrodes continuously, as processing heat accumulates in rolls, leading to expansion and a decrease in layer thickness.
Innovation Solution
A manufacturing method involving a cooling device that cools the metal foil before it reaches the rolls, using a cooling roll with a refrigerant supply and a sensor to maintain the foil at a temperature lower than the air temperature but higher than the dew point, and heating the first roll to ensure processing heat is transferred to the foil, thereby preventing roll expansion and maintaining layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electrode is manufactured continuously for a long period of time, then productivity is improved, but processing heat accumulates in the rolls causing them to expand and the active material layer thickness decreases
Solution Approach 1:
The foil is cooled down in advance by the cooling device before it reaches the transferring position between the rolls. This preliminary cooling action ensures that the foil absorbs processing heat during transfer, preventing heat accumulation in the rolls and maintaining gap distance and layer thickness even during continuous production
Solution Approach 2:
The processing heat generated during active material transfer, which was previously causing harmful heat accumulation in the rolls, is converted into a beneficial effect by having the cooled foil absorb this heat. The heat that would otherwise expand the rolls is now used to maintain the foil at an appropriate temperature, preventing roll expansion and maintaining manufacturing precision
2Manufacturing precision
If the rolls are cooled to prevent expansion, then manufacturing precision is improved, but additional cooling equipment and complexity are required
Solution Approach 1:
The foil serves its own cooling function by absorbing processing heat during the transfer process. Instead of requiring complex active cooling systems for the rolls, the system uses the foil itself as the cooling medium, simplifying the overall device complexity while maintaining manufacturing precision
3Temperature
If the foil temperature is lowered below dew point for maximum cooling effect, then heat absorption is improved, but condensation occurs on the foil surface
Solution Approach 1:
The cooling device incorporates temperature sensing and control that monitors the foil temperature and adjusts cooling intensity to maintain temperature above the dew point. This feedback control prevents condensation while still achieving sufficient cooling效果 to absorb processing heat and prevent roll expansion
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 method ensures the active material layer thickness remains within an appropriate range even during continuous production, preventing roll expansion and maintaining the integrity of the electrode layer.
Implementation Method 1
cooling down the foil by use of a cooling device on an upstream side relative to the second roll in terms of a conveying direction of the foil
Implementation Method 2
the refrigerant supply portion cause the refrigerant having a temperature lower than the air temperature of the manufacture environment to flow through the cooling roll
Data Source
AI summary
A manufacturing method manufactures an electrode by use of a manufacturing apparatus including a B-roll configured to convey granules, a C-roll configured to convey a metal foil, and a cooling portion configured to cool down the metal foil on an upstream side relative to the C-roll in terms of a conveying direction of the metal foil. Further, the manufacturing apparatus cools down the metal foil by use of the cooling portion, supplies the metal foil thus cooled down by the cooling portion to the C-roll, and transfers the granules to the metal foil in a deposition gap between the B-roll and the C-roll.