Stepped Die Coater Shim for Uniform Electrode Edge Coating

Solution Overview

Problem

Existing die coaters struggle with inconsistent slurry thickness distribution, particularly at the edge portions of electrodes, leading to NP ratio reversals during secondary battery manufacturing.

Innovation Solution

A shim for die coaters featuring guides with steps and sub-guides that control the slurry discharge line, ensuring even application on electrode current collectors, including first and second guides with specific thickness variations and optional sub-guides to manage the discharge line.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional die coater is used to apply slurry on electrode current collector, then the slurry can be coated on the electrode, but the thickness distribution of slurry is inconsistent especially at edge portions causing NP ratio reversal

Engineering Contradiction:

Improveslurry thickness distributionVSAvoidNP ratio consistency

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The shim introduces local quality variations through stepped structures at specific positions (3/10 to 6/10 of thickness) to control slurry flow distribution. The different thickness regions (1-2mm in non-step areas, 0.4-0.9mm in step areas) create localized flow resistance differences that compensate for edge portion slurry deficiency, achieving uniform thickness distribution across the electrode surface.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The shim acts as an intermediary component installed within the die coater's inner space between the slurry supply and the electrode current collector. This intermediate structure modifies the slurry discharge characteristics by introducing controlled resistance through its stepped geometry, thereby regulating the slurry flow to achieve consistent thickness without directly contacting or becoming part of the electrode structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If the discharge port is made thin and wide to spread slurry widely, then the slurry can be widely coated on metal foil, but the edge portion application becomes difficult and NP ratio reversal occurs

Engineering Contradiction:

Improveslurry coating areaVSAvoidedge portion thickness uniformity

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The shim introduces local quality variations through stepped structures at specific positions (3/10 to 6/10 of thickness) to control slurry flow distribution. The different thickness regions (1-2mm in non-step areas, 0.4-0.9mm in step areas) create localized flow resistance differences that compensate for edge portion slurry deficiency, achieving uniform thickness distribution across the electrode surface.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The shim adds a dimensional element to the discharge port structure by introducing thickness variations (stepped structures) in the Z-dimension (depth direction). This dimensional modification creates multiple flow resistance levels that guide slurry distribution across the width, ensuring adequate reach to edge portions while maintaining thickness uniformity through the controlled resistance profile.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12551918B2Shim for die coater, die coater comprising same, and lithium secondary battery comprising cathode manufactured using same

Publication Date: 2026.02.17 LG ENERGY SOLUTION LTD

AI summary

The present technology relates to a shim for a die coater, a die coater including the shim, and a lithium secondary battery including a positive electrode manufactured using the die coater of the present invention, and according to the present technology, it is possible to smoothly apply slurry on the edge portion.