Induction Drying of Electrode-Separator Composites Under Vacuum
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for drying electrode-separator assemblies in lithium-ion cells are inefficient, time-consuming, and energy-intensive, often resulting in uneven heating, residue formation, and potential damage to the cells due to poor heat transfer and temperature control.
Innovation Solution
An inductive heating method using elongated inductors to apply a targeted and contactless magnetic field to each electrode-separator assembly, ensuring uniform and rapid drying under vacuum conditions, with individual control and regulation to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional oven drying methods are used, then the electrode-separator assemblies can be dried, but the process is time-consuming and energy-intensive with uneven heating
Solution Approach 1:
The patent replaces the conventional thermal convection system (oven heating) with an electromagnetic induction system. Induction coils generate alternating magnetic fields that directly induce eddy currents in the metallic current collectors, converting electromagnetic energy directly into heat within the electrode assemblies themselves, eliminating the need for external thermal fields and significantly reducing energy loss.
Solution Approach 2:
The patent employs alternating current through the induction coils, creating periodic magnetic fields that continuously induce eddy currents in the current collectors. This periodic electromagnetic action enables rapid and uniform heating throughout the electrode-separator assemblies, achieving thorough drying in minutes rather than hours.
2Manufacturing precision
If conventional oven drying is used, then drying can be performed, but heat transfer is poor resulting in uneven heating and potential cell damage
Solution Approach 1:
The patent replaces external thermal convection with internal electromagnetic heating. The alternating magnetic fields penetrate the electrode assemblies and directly induce eddy currents in the current collectors, generating heat uniformly throughout the entire assembly simultaneously, eliminating temperature gradients and hot spots that cause cell damage.
Solution Approach 2:
The patent changes the heating mechanism from thermal conduction/convection to electromagnetic induction. By adjusting the frequency and amplitude of the alternating current through the induction coils, precise control over the heating rate and temperature distribution is achieved, ensuring uniform heating without exceeding damage thresholds.
3Loss of time
If conventional drying methods are used, then the process can be completed, but it requires excessive time
Solution Approach 1:
The patent uses high-frequency alternating current through induction coils to generate rapidly oscillating magnetic fields. These periodic electromagnetic fields continuously induce eddy currents in the current collectors, producing rapid and uniform heating that reduces drying time from hours to minutes, dramatically improving manufacturing efficiency.
Solution Approach 2:
The patent replaces slow thermal diffusion-based drying with rapid electromagnetic induction heating. The direct conversion of electromagnetic energy to heat within the current collectors enables extremely fast heating rates, achieving complete drying in a fraction of the time required by conventional oven methods.
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
Achieves rapid, energy-efficient, and homogeneous drying of multiple electrode-separator assemblies, reducing drying time by up to 50-75% and minimizing cell damage, while allowing for flexible drying curves and quality control.
Implementation Method 1
the plurality of electrode-separator assemblies are inductively heated by means of at least two inductors (20) which are each assigned to one of the electrode-separator assemblies (10)
Implementation Method 2
the electrode-separator assemblies are inductively heated by means of at least two inductors (20)
Implementation Method 3
Solvents and/or suspending agents contained in the compositions are typically found in the electrode films formed on the current collectors and must be removed
Implementation Method 4
a vacuum is applied for thermal drying treatment
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The invention proposes a method and an apparatus for the thermal drying treatment of a plurality of electrode-separator composites (10). The composites each have at least one negative and at least one positive electrode, which each comprise a metal current collector coated with electrode active material, specifically an anode current collector and a cathode current collector. All composites are dried simultaneously during the thermal drying treatment. The drying is performed by means of a plurality of inductors (20), by means of which the electrode-separator composites (10) are inductively heated. In the method a plurality of electrode-separator composites (10) are placed in a drying apparatus in the region of action of the inductors (20). For the thermal drying treatment, a vacuum is applied and the inductors (20) are supplied with current. The method is further characterised in that each of the electrode-separator composites (10) to be dried in the drying apparatus is associated with precisely one inductor (20) or more than two electrode-separator composites (10) are associated with one inductor (200), which generates a magnetic alternating field of elongate expanse, in which the more than two electrode-separator composites (10) can be arranged so that these are each exposed to substantially the same magnetic field strength in the alternating field.