Dry Electrode Coating Width Control for Accumulator Cells

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Solution Overview

Problem

Current methods for producing electrodes for lithium-ion batteries often rely on solvent-based processes, which can be inefficient and result in inconsistent coating widths, leading to suboptimal electrode performance and increased production costs.

Innovation Solution

A solvent-free dry electrode production method using a device with multiple rollers to apply and compact electrode active materials directly onto metal foil strips, allowing for precise control of coating width through mechanical elements like pinch knives and scrapers, ensuring consistent and high-quality coatings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If solvent-based coating processes are used, then the coating application is easier, but the manufacturing precision of coating width deteriorates

Engineering Contradiction:
Improvecoating application processVSAvoidcoating width consistency
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent removes the solvent component from the coating process entirely, using only dry powder coating material. This extraction of the solvent eliminates the inconsistency issues associated with solvent evaporation and drying, while maintaining ease of application through the dry powder formulation that can be uniformly distributed by the roller mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the chemical-based solvent application system with a mechanical dry powder application system. The coating material is applied as dry powder through mechanical means (rollers,刮 blades) rather than through solvent-based chemical processes, improving precision while maintaining manufacturability.

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

2Manufacturing precision

If mechanical elements like pinch knives and scrapers are added to control coating width, then the manufacturing precision of coating width improves, but the device complexity increases

Engineering Contradiction:
Improvecoating width controlVSAvoidnumber of mechanical elements
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the coating width control function into separate mechanical elements: pinch knives for defining the leading edge and scrapers for controlling the trailing edge. This segmentation allows each element to perform a specific function independently, achieving precise coating width control through simple, modular components rather than a complex integrated system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of trying to control coating width by adjusting the application process itself, the patent inverts the approach by using mechanical elements that physically remove or define the coating edges after application. The pinch knives and scrapers work by subtraction and definition rather than by precise positive control of the application boundaries.

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

3Loss of substance

If excess coating material is removed and reused, then the loss of substance decreases, but the processing time increases

Engineering Contradiction:
Improveexcess material wasteVSAvoidmaterial recovery time
Core Design Contradiction:
Loss of substanceVSLoss of time

Solution Approach 1:

The patent implements a material recovery system where excess coating material removed by the scrapers is collected and fed back into the coating process. This closed-loop system recovers what would otherwise be waste material, minimizing substance loss while integrating the recovery process into the continuous production flow to minimize time penalties.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The patent maintains continuous operation of the coating process with the scrapers and material recovery system integrated into the same production line. The excess material is removed and reused in a continuous manner rather than through batch processing, minimizing interruptions and maintaining continuous useful action throughout the process.

Inventive Principle:
Principle #20Continuity of useful action

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 enables efficient, solvent-free production of electrodes with precise coating widths, enhancing performance and reducing waste, while maintaining high-quality edges and allowing for the reuse of excess material, thus improving the overall efficiency and cost-effectiveness of the battery production process.

Implementation Method 1

The coating material is applied or applied to the first side using a first application roller. In particular, the coating material is transferred directly from the first application roller to the material strip. Thus, the coating material is essentially rolled onto the material strip.

Methodology Applied
Scientific EffectRolling: Roller

Implementation Method 2

A particularly advantageous process variant is one in which the coating material is compacted on the first application roller by means of a first pressure roller.

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

The first coating width is determined by means of a squeezing knife, in particular by means of a squeezing cut on the first application roller.

Methodology Applied
Scientific EffectMechanical cutting: Wedge

Implementation Method 4

An alternative variant is a so-called kiss cut or roller punching. It is also advantageous if the first coating width is specified using a scraper, which scrapes the coating material off the first application roller.

Methodology Applied
Scientific EffectScraping: Friction

Data Source

PatentEP4421893A1Method for producing electrodes for accumulator cells, device for producing electrodes for accumulator cells, and accumulator
Publication Date: 2024.08.28 POWERCO SE
  • EP4421893A1 patent drawingFigure 1
  • EP4421893A1 patent drawingFigure 2
  • EP4421893A1 patent drawing

AI summary

The invention relates to a method for manufacturing electrodes for accumulator cells, wherein a material strip (4) is coated at least on a first side (14) with a coating material (6) and wherein the coating material (6) is applied to the first side (14) by means of a first application roller (10).