Bipolar Electrode Layer Densification With Separate Pressing

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Solution Overview

Problem

Conventional methods for producing bipolar electrodes struggle to adjust the positive and negative electrode mixture layers to arbitrary densities and densities, failing to form them effectively on both surfaces of an electrode foil.

Innovation Solution

A method involving separate pressing steps for positive and negative electrode mixture layers, using a screen printing method to form the positive and negative electrode mixture coating films, and optimizing the densities of the positive and negative electrode mixture layers, respectively, with separate pressing steps for screen printing method to form the positive and negative electrode mixture layers, respectively, with the positive electrode mixture layer and the negative electrode mixture layer being adjusted to arbitrary densities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If collective pressing is performed after coating both positive and negative electrode mixture coating liquids, then the production process is simplified, but it becomes difficult to respectively adjust the positive and negative electrode mixture layers to arbitrary densities

Engineering Contradiction:

Improveproduction process simplicityVSAvoiddensity adjustment precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The pressing process is segmented into two separate operations: first pressing the positive electrode mixture layer, then pressing the negative electrode mixture layer. This segmentation allows independent control of pressing parameters for each layer, enabling arbitrary density adjustment for both layers while maintaining a relatively simple production process.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If separate pressing steps are performed for positive and negative electrode mixture layers, then arbitrary density adjustment is achieved, but the production process becomes more complex

Engineering Contradiction:

Improvedensity adjustment precisionVSAvoidpressing process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The positive and negative electrode mixture layers are coated on the same electrode foil in sequence, and both are pressed using the same pressing device with separate pressing steps. This merging approach allows independent density control while avoiding the need for separate pressing devices or complex multi-step processes, thus limiting the increase in device complexity.

Inventive Principle:

Principle #5Merging (Combining)

3Manufacturing precision

If screen printing method is used for coating negative electrode mixture, then coating precision is improved, but the process requires additional process parameters optimization

Engineering Contradiction:

Improvecoating precisionVSAvoidprocess parameter flexibility

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The screen printing process parameters (mesh size, printing pressure, squeegee speed) are optimized within specific ranges to achieve precise coating while maintaining flexibility. The viscosity of the negative electrode mixture coating liquid is controlled within 10,000-30,000 mPa·s, and printing pressure is set at 0.15-0.4 MPa, allowing precise control without overly restricting process adaptability.

Inventive Principle:

Principle #35Parameter changes

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

The method allows for the formation of bipolar electrodes with improved energy density in the positive electrode mixture layer and enhanced ion diffusivity in the negative electrode mixture layer, while ensuring precise control over their densities.

Implementation Method 1

coating a negative electrode mixture coating liquid on the other surface of the electrode foil by a screen printing method

Methodology Applied

Scientific EffectScreen printing:

Implementation Method 2

a first pressing step of pressing the electrode foil having the positive electrode mixture coating film; a second pressing step of pressing the electrode foil having the negative electrode mixture coating film

Methodology Applied

Scientific EffectPressing: Compression

Implementation Method 3

drying the positive electrode mixture coating liquid, to form a positive electrode mixture coating film; drying the negative electrode mixture coating liquid, to form a negative electrode mixture coating film

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS20250372594A1Method for producing bipolar electrode

Publication Date: 2025.12.04 TOYOTA JIDOSHA KK

AI summary

A method for producing a bipolar electrode includes obtaining a bipolar electrode respectively having a positive electrode mixture layer and a negative electrode mixture layer at both surfaces of an electrode foil through: a positive electrode mixture coating step of coating a positive electrode mixture coating liquid on one surface of an electrode foil and drying the positive electrode mixture coating liquid, to form a positive electrode mixture coating film; a first pressing step of pressing the electrode foil having the positive electrode mixture coating film; a negative electrode mixture coating step of coating a negative electrode mixture coating liquid on another surface of the electrode foil by a screen printing method and drying the negative electrode mixture coating liquid, to form a negative electrode mixture coating film; and a second pressing step of pressing the electrode foil having the negative electrode mixture coating film.