Battery Electrode Coating Speckle Imaging for Inline Moisture Control

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Solution Overview

Problem

Current manufacturing processes for battery electrodes struggle with maintaining coating uniformity, particularly in terms of residual moisture, thickness, and surface roughness, leading to high reject rates and inferior battery cell quality due to the lack of effective inline monitoring and the need for costly, complex sensor systems.

Innovation Solution

An electromagnetic radiation-based method is employed to determine coating parameters such as residual moisture, layer thickness, and roughness by generating a speckle pattern, which is analyzed using a camera and artificial neural networks to adjust production processes in real-time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If intensive overdrying process is employed to ensure residual moisture content remains below maximum value, then residual moisture control is improved, but energy consumption increases considerably

Engineering Contradiction:
Improveresidual moisture controlVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by stationary object

Solution Approach 1:

The patent applies preliminary action by performing inline monitoring of residual moisture during the drying process using electromagnetic radiation and dielectric spectroscopy. This allows the drying process to be optimized in real-time, applying energy only when and where needed to achieve target moisture levels, rather than using intensive overdrying for all cases.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback control by continuously measuring residual moisture content during the drying process using electromagnetic radiation transmission and dielectric spectroscopy. The measured values are fed back to control the drying process, allowing dynamic adjustment of energy input to maintain moisture levels within specifications while minimizing energy consumption.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If multiple different sensor types are used for inline monitoring of coating parameters, then measurement capability is improved, but system cost and complexity increase

Engineering Contradiction:
Improvecoating parameter monitoring capabilityVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies universality by using electromagnetic radiation in multiple frequency ranges (microwave, millimeter wave, terahertz) to simultaneously measure multiple coating parameters including residual moisture content, layer thickness, and surface roughness. This multi-functional approach replaces the need for multiple separate sensor systems with a single integrated electromagnetic radiation-based measurement system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent utilizes parameter changes by measuring coating properties across different electromagnetic radiation frequencies and wavelengths. By analyzing how the coating interacts with electromagnetic radiation at various frequencies (transmission, reflection, absorption characteristics), the system extracts multiple parameters simultaneously, reducing the need for multiple specialized sensors.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional sensor systems are used for inline monitoring, then some parameters can be monitored, but comprehensive coating quality monitoring remains insufficient leading to high reject rates

Engineering Contradiction:
Improvecoating quality assuranceVSAvoidreject rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by performing comprehensive inline monitoring of multiple coating parameters (residual moisture, layer thickness, surface roughness, homogeneity) during the manufacturing process. This early detection capability allows for immediate corrective actions before defective products are completed, significantly reducing reject rates compared to conventional post-production inspection methods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements comprehensive feedback control by continuously monitoring multiple coating quality parameters simultaneously using electromagnetic radiation techniques. The real-time measurement data provides feedback to control the coating and drying processes, enabling dynamic adjustments to maintain quality specifications and prevent production of defective battery cells.

Inventive Principle:
Principle #23Feedback

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

Enables inline monitoring of coating quality, reducing reject rates and improving electrode quality by allowing for immediate corrective actions during the manufacturing process, thus enhancing the efficiency and effectiveness of battery production.

Implementation Method 1

electromagnetic radiation IRR is applied using an EM source to heat a specified region of the coating

Methodology Applied
Scientific EffectElectromagnetic radiation heating: Dielectric Heating

Implementation Method 2

the reflected radiation field IRR_REFL exhibits an interference pattern formed as a speckle pattern SPECK

Methodology Applied
Scientific EffectSpeckle pattern formation: Scattering

Data Source

PatentEP4657045A1Determining characterizing parameters of a coating of a battery electrode
Publication Date: 2025.12.03 SIEMENS AG
  • EP4657045A1 patent drawingFigure 1
  • EP4657045A1 patent drawingFigure 2
  • EP4657045A1 patent drawing

AI summary

The invention relates to the determination of characteristic parameters of a battery electrode coating, in particular residual moisture and/or coating thickness, during the manufacturing of the battery electrode. For this purpose, electromagnetic radiation (IRR) is applied to the coating for drying, generating a reflected radiation field characterized by a speckle interference pattern. The reflected radiation field, and thus the characteristic speckle pattern, is recorded with a camera. The resulting images allow the coating parameters to be derived from the respective speckle pattern depicted.