Inductive Drying of Electrode Films on Metal Current Collectors

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Solution Overview

Problem

The existing methods for producing lithium-ion battery electrodes are time-consuming and energy-intensive due to the slow drying process of electrode films on metallic current collectors, often resulting in film residues and bubbles, as the solvent and suspending agents take longer to evaporate, especially when heated from the outside.

Innovation Solution

The method employs inductive heating of the metallic current collector to efficiently dry the electrode films by generating eddy currents, which heat the collector and subsequently the film from the inside, expelling the solvent and suspending agents, thereby accelerating the drying process and reducing residue formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If electrode films are dried using temperature-controlled gas heating from the outside, then the drying process can be performed with simple equipment, but the drying time is long and energy consumption is high

Engineering Contradiction:
Improvedrying equipment structureVSAvoiddrying time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

Instead of heating the electrode film from the outside surface using gas, the invention inverts the heating approach by using inductive heating to heat the metallic current collector from the inside, which then transfers heat to the electrode film. This internal heating method dramatically reduces drying time while maintaining equipment simplicity.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention replaces the mechanical/conventional thermal heating system (temperature-controlled gas) with an electromagnetic field-based inductive heating system. This substitution enables rapid heating of the metallic current collector, reducing drying time from hours to minutes while eliminating the need for complex gas flow control systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If electrode films are dried using temperature-controlled gas heating from the outside, then the heating process is simple to implement, but energy consumption is high

Engineering Contradiction:
Improveheating process implementationVSAvoidenergy consumption
Core Design Contradiction:
Ease of manufactureVSUse of energy by stationary object

Solution Approach 1:

The invention replaces conventional thermal heating with inductive heating, which uses electromagnetic fields to directly heat the metallic current collector. This method is highly energy-efficient because it heats the substrate directly rather than heating a large volume of gas, reducing energy consumption while maintaining ease of implementation through automated induction heating systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the heating parameter from external gas temperature control to internal electromagnetic field induction. This parameter change enables rapid and uniform heating of the current collector, significantly reducing the energy required to achieve the same drying effect compared to conventional external heating methods.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If electrode films are heated from the outside, then the heating method is straightforward, but film residues and bubbles remain

Engineering Contradiction:
Improveheating methodVSAvoidfilm quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention inverts the heating direction by heating the metallic current collector from the inside through inductive heating, rather than heating from the outside surface. This internal heating approach ensures uniform temperature distribution throughout the film, preventing residue formation and bubble entrapment that occur with external heating methods.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention changes the heating parameter from external surface heating to internal volumetric heating of the current collector. This parameter change results in uniform heat distribution that prevents localized overheating and ensures complete solvent removal, eliminating film residues and bubbles while maintaining manufacturing simplicity.

Inventive Principle:
Principle #35Parameter changes

4Use of energy by stationary object

If solvent and suspending agents are evaporated slowly, then the drying process is energy-efficient, but production productivity is low

Engineering Contradiction:
Improveenergy efficiencyVSAvoidproduction speed
Core Design Contradiction:
Use of energy by stationary objectVSProductivity

Solution Approach 1:

The invention uses periodic alternating electromagnetic fields for inductive heating, which enables rapid and controlled evaporation of solvents. This periodic action allows for fast drying (improving productivity) while maintaining energy efficiency through controlled heating cycles that prevent excessive energy consumption.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The invention replaces slow conventional thermal evaporation with rapid inductive heating, which uses electromagnetic fields to directly heat the current collector and accelerate solvent removal. This substitution dramatically increases production speed while maintaining energy efficiency through targeted and controlled heating of only the necessary components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 significantly reduces the drying time, prevents film residue and bubble formation, and enhances the efficiency of the electrode film production by heating the current collector internally, ensuring faster and more uniform drying of the electrode films.

Implementation Method 1

the electrode film is inductively heated by an induction device

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

heating the collector and subsequently the film from the inside, expelling the solvent and suspending agents

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Data Source

PatentEP3662525B1Method for thermally treating an electrode film on a metal current collector
Publication Date: 2023.11.08 VW KRAFTWERK
  • EP3662525B1 patent drawingFigure 1~2

AI summary

In a method for thermally treating at least one electrode film (111a; 111b) on a metal current collector (110), said current collector is inductively heated. The invention relates to the method as such as well as to a device (100) suitable for carrying out the method.