Dry Electrode Calender Coating With Uniform Powder Metering

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Solution Overview

Problem

Conventional methods for producing lithium-ion battery electrodes are complex and require significant manufacturing effort, with challenges in achieving consistent and reliable coating processes.

Innovation Solution

A method using a discharge system with rotating calender rollers to compact powdery electrode material into a film, ensuring temporal and spatially constant powder dosage through a controlled dosing concept, including a reservoir, sieve, and vibrational elements to prevent pre-compaction and ensure even distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional wet coating process is used to apply electrode material to current collector foil, then the coating process can be performed, but the manufacturing process becomes technically complex and requires significant manufacturing effort

Engineering Contradiction:
Improvemanufacturing effortVSAvoidprocess complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent changes the physical state parameter of the electrode material from viscous (wet coating) to powdered (dry coating). This fundamental parameter change enables a simpler process without requiring complex discharge systems, drying stations, or calendering mills, thereby reducing manufacturing effort and process complexity while achieving the same coating function

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts and eliminates the unnecessary intermediate steps from the conventional wet coating process. By removing the discharge system, drying station, and calendering mill components, the process is simplified to direct powder application and compaction, reducing manufacturing effort without compromising coating quality

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If powder is discharged into the roller gap without controlled dosing, then the process is simpler, but temporal and spatial distribution of powder becomes uneven leading to inconsistent electrode material application

Engineering Contradiction:
Improvepowder dosage consistencyVSAvoiddosing system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies mechanical vibration to the sieve structure in the dosing system. This vibration prevents powder bridging and ensures uniform temporal and spatial distribution of powdered electrode material into the roller gap, achieving consistent dosage without requiring complex automated dosing equipment

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The patent introduces a sieve as an intermediary element between the powder reservoir and the roller gap. The sieve acts as a mediating structure that controls and uniformizes powder flow, ensuring consistent temporal and spatial dosage while keeping the overall dosing system simple and mechanically straightforward

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If powdered electrode material is allowed to accumulate in the roller gap feed area, then continuous supply is maintained, but pre-compaction occurs reducing process reliability

Engineering Contradiction:
Improveprocess reliabilityVSAvoidpowder flow continuity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies mechanical vibration to the roller gap feed area to prevent powder accumulation and pre-compaction. The vibration keeps the powder in a loose, flowable state, ensuring continuous supply to the compaction zone while maintaining process reliability by preventing premature densification of the electrode material

Inventive Principle:
Principle #18Mechanical vibration

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 reduces manufacturing effort and enhances process reliability by achieving consistent electrode material application, preventing pre-compaction and ensuring uniform layer formation across the coating width.

Implementation Method 1

the powdered starting component can be discharged under gravity directly into the roller gap intake area

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

The sieve can be set into vibration by means of an exciter, such as an ultrasonic or electrical exciter

Methodology Applied
Scientific EffectVibration: Vibration

Implementation Method 3

the transport chute can also be set into vibration by means of such an exciter

Methodology Applied
Scientific EffectVibration: Vibration

Implementation Method 4

A dosing device, particularly a gravimetric weighing unit, can be installed upstream of the discharge system

Methodology Applied
Scientific EffectGravimetric measurement:

Implementation Method 5

compacted there under pressure and shear to form an electrode material film

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 6

compacted there under pressure and shear to form an electrode material film

Methodology Applied
Scientific EffectShear stress: Shear Stress

Data Source

PatentEP4376112A1Method and process arrangement for producing an electrode for a battery cell
Publication Date: 2024.05.29 VOLKSWAGEN AG
  • EP4376112A1 patent drawingFigure 1
  • EP4376112A1 patent drawingFigure 2~3
  • EP4376112A1 patent drawingFigure 4~5

AI summary

The invention relates to a method for manufacturing an electrode for a battery cell, comprising a coating process in which a current collector foil (1) is coated with electrode material (3) by means of a discharge system (9), wherein the discharge system (9) has a pair of rollers with rotating calender rollers (27) spaced apart from each other by a roller gap (25), and wherein a powdered starting component (5) of the electrode material (3) is filled in a dry state into a roller gap feed area (23) and compacted in the roller gap (25) under pressure and shear to form an electrode material film (43, 43') which is applied to the current collector foil (1). According to the invention, the discharge system (9) ensures a temporally and spatially constant and/or adjustable powder metering into the roller gap (25).