Electrode Layer Coating With Screw Pump Density Uniformity

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Solution Overview

Problem

Existing methods for manufacturing electrode layers in batteries face challenges in achieving uniform material density and in-plane uniformity, particularly when using powders containing electrode active materials, due to air mixing and non-uniform pressure application during film formation, leading to non-uniform density states.

Innovation Solution

A method involving the use of a screw pump with a cylindrical housing, a screw, and a shielding material to supply an electrode material containing electrode active material, conductive auxiliary agent, and electrolytic solution onto a collector foil, applying shearing and pressure to achieve uniform density, using a screw with decreasing helical pitch and a shielding material with through-holes to control material discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If pre-mixed electrode material is supplied onto collector foil using conventional methods, then film formation can be achieved, but the material density becomes non-uniform in the in-plane direction

Engineering Contradiction:
Improvein-plane uniformity of material densityVSAvoiddensity state uniformity
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent changes the physical state parameters of the electrode material by controlling the concentration of solid components (40-80% by volume) and adjusting the flow characteristics through screw pump parameters. This enables the material to be supplied in a controlled semi-fluid state that maintains uniform density during deposition, resolving the contradiction between achieving film formation and maintaining density uniformity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces conventional mechanical mixing and coating systems with a screw pump-based supply system. The screw pump uses rotational mechanical action to continuously mix and supply the electrode material without introducing air bubbles, thereby achieving uniform density distribution across the electrode layer while maintaining stable composition.

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

2Manufacturing precision

If pressure is applied in an accumulative manner during film formation, then coating can be achieved, but pressure distribution becomes non-uniform (initial stage vs final stage)

Engineering Contradiction:
Improvematerial density uniformityVSAvoidpressure distribution uniformity
Core Design Contradiction:
Manufacturing precisionVSStress or pressure

Solution Approach 1:

The screw pump provides continuous supply of electrode material at a constant rate to the collector foil. This continuous action ensures that pressure is applied uniformly throughout the coating process, eliminating the non-uniform pressure distribution that occurs with accumulative pressure application where initial and final stages differ.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent introduces dynamic control of the material supply process through the rotating screw mechanism. The screw pump dynamically adjusts the material flow and pressure application in real-time, ensuring uniform pressure distribution across the entire coating area and throughout the coating duration, rather than applying static accumulative pressure.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If mixed material is stored in a container, then material preparation is simplified, but gravitational densification causes non-uniform density (top vs bottom portions)

Engineering Contradiction:
Improvematerial preparation simplicityVSAvoiddensity uniformity
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent replaces static gravitational storage with a dynamic screw pump supply system. Instead of relying on gravitational force to settle and densify the material in a container (which causes non-uniform density), the screw pump actively transports the material in a controlled manner, continuously mixing and supplying it at uniform density to the collector foil.

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

Solution Approach 2:

The screw pump performs preliminary mixing and density equalization of the electrode material before supply to the collector foil. By pre-processing the material flow to ensure uniform density distribution, the system prevents the gravitational densification problem that would otherwise occur during storage, while still maintaining ease of manufacture through automated continuous supply.

Inventive Principle:
Principle #10Preliminary 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

The method enables the production of electrode layers with high uniformity of material density, improving battery performance by ensuring consistent density across the electrode layer and between multiple layers.

Implementation Method 1

The screw pump includes a screw that is installed rotatably inside the cylindrical housing and has a pitch region having a helical pitch decreasing in a downstream discharge direction of the electrode material

Methodology Applied
Scientific EffectShear stress: Shear Stress

Implementation Method 2

a shielding material that is disposed at the discharge port, and the shielding material has a surface intersecting an axial direction of the screw and a through-hole penetrating the surface

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP4697407A1Method of producing electrode layer
Publication Date: 2026.02.18 FUJIFILM CORP
  • EP4697407A1 patent drawingFigure 1
  • EP4697407A1 patent drawingFigure 2
  • EP4697407A1 patent drawingFigure 3~4

AI summary

An embodiment of the present invention is a method for manufacturing an electrode layer, including a step A of supplying an electrode material which contains an electrode active material, a conductive auxiliary agent, and an electrolytic solution, and has a concentration of solid components of 40% by volume to 80% by volume onto a collector foil using a screw pump, and a step B of leveling the electrode material supplied onto the collector foil to form an electrode layer on the collector foil, in the screw pump includes a cylindrical housing that has, at one end, a supply port through which the electrode material is supplied, and has, at the other end, a discharge port through which the electrode material is discharged, a screw that is installed rotatably in the cylindrical housing and has a pitch region having a helical pitch decreasing in a downstream discharge direction of the electrode material, and a shielding material that is disposed at the discharge port, and the shielding material has a surface intersecting an axial direction of the screw and a through-hole penetrating the surface, the surface faces a downstream edge surface of a screw blade of the screw in a noncontact manner, and the through-hole is provided at a position facing the downstream edge surface.