EP-4737016-A1 - INSULATING LIQUID FLOW PATH STRUCTURE OF SLOT DIE COATER

EP4737016A1EP 4737016 A1EP4737016 A1EP 4737016A1EP-4737016-A1

Abstract

Disclosed herein relates to a slot die coater including a first die block provided with a manifold for accommodating an electrode slurry; a second die block coupled to the first die block; and a coater shim interposed between the first die block and the second die block, wherein the coater shim includes: a body shim that wraps around both sides and the rear surface of the manifold, and a plurality of spacer shims spaced apart between the body shims so as to traverse toward the front surface of the manifold, with concave insulating solution flow path formed on their surfaces, wherein the plurality of spacer shims include: a first spacer shim whose position is fixed relative to the body shim, and a second spacer shim that is movable within the first spacer shim.

Inventors

PARK, MIN GU
MOON, YOUNG GYU
CHOI, MIN HYUCK
KIM, GUK TAE
LIM, Chae Ryeun
KIM, MIN CHEOL

Assignees

LG Energy Solution, Ltd.

Dates

Publication Date: 20260506
Application Date: 20250411

Claims (13)

A slot die coater comprising: a first die block provided with a manifold for accommodating an electrode slurry; a second die block coupled to the first die block; and a coater shim interposed between the first die block and the second die block, wherein the coater shim comprises: a body shim that wraps around both sides and a rear surface of the manifold, and a plurality of spacer shims spaced apart between the body shims so as to traverse toward a front surface of the manifold, with a concave insulating solution flow path formed on their surfaces, wherein the plurality of spacer shims comprise: a first spacer shim whose position is fixed relative to the body shim, and a second spacer shim that is movable within the first spacer shim.
The slot die coater of claim 1, wherein a flow cross-sectional area of the insulating solution flow path changes in accordance with a movement of a position of the second spacer shim.
The slot die coater of claim 2, wherein the second spacer shim is capable of linear movement in a transverse direction.
The slot die coater of claim 3, wherein the first spacer shim is equipped with an accommodating part having an open front surface, wherein the second spacer shim is disposed within the accommodating part, and is equipped with a guide hole in the form of a long hole extending in the transverse direction, providing a fastening margin relative to a fixing pin located within the accommodating part.
The slot die coater of claim 4, wherein the fixing pin is provided in the first die block.
The slot die coater of claim 3, wherein an insulating solution supply hole that supplies insulating solution to the insulating solution flow path is formed within the first spacer shim.
The slot die coater of claim 6, wherein a gap between the first spacer shim and the second spacer shim, which is open in the machine direction while communicating with the insulating solution supply hole, forms a portion of a distal end of the insulating solution flow path.
The slot die coater of claim 2, wherein the second spacer shim is capable of performing a rotary motion in which an angle of a centerline relative to a machine direction changes.
The slot die coater of claim 8, wherein the first spacer shim is equipped with an accommodating part having an open front surface, wherein the second spacer shim is disposed within the accommodating part, and is equipped with a rotary hole that is coupled so that it can perform a rotary motion relative to a fixing pin located inside the accommodating part.
The slot die coater of claim 9, wherein a circular arc-shaped rotary contact surface, with a center of the fixing pin as a center of curvature, is formed between the first spacer shim and the second spacer shim.
The slot die coater of claim 9, wherein the fixing pin is provided on the first die block.
The slot die coater of claim 9, wherein an insulating solution supply hole that supplies insulating solution to the insulating solution flow path is formed within the first spacer shim.
The slot die coater of claim 12, wherein a gap between the first spacer shim and the second spacer shim, which is open in the machine direction while communicating with the insulating solution supply hole, forms a portion of a distal end of the insulating solution flow path.

Description

[Technical Field] The present disclosure relates to a slot die coater that simultaneously discharges electrode slurry and insulating solution onto an electrode foil, and specifically to an insulating solution flow structure of a slot die coater that allows easy control of the discharge amount of insulating solution by adjusting the position of a spacer shim. This application claims the benefit of Korean Patent Application No. 10-2024-0051318, filed on April 17, 2024, the disclosure of which is incorporated herein by reference. [Background] Lithium secondary batteries are widely used not only in small devices such as portable electronic devices but also in medium-to-large devices such as battery packs or power storage devices for hybrid vehicles or electric vehicles. In particular, with growing concern over environmental issues, research on electric vehicles and hybrid vehicles, which can replace fossil fuel-powered vehicles such as gasoline and diesel vehicles that are one of the major causes of air pollution, has been actively conducted. Generally, lithium secondary batteries consist of an electrode assembly, consisting of a positive electrode, a negative electrode, and a separator, is immersed in a lithium electrolyte. The electrodes are formed by coating an electrode slurry containing the active material onto an electrode current collector. For this coating process, coating devices such as a slot die coater are used. The slot die coater includes an upper die block and a lower die block that form a chamber for supplying the electrode slurry, and a shim member positioned between them to set the height and width of the slot that discharges the active material slurry. The space between the plurality of shim members forms the slot. The height of the slot through which the active material slurry is discharged is determined by the height of the shim member, and the width of the slot is determined by the distance between the spaced-apart shim members. When coating electrode slurry using a slot die coater, the shape of the edges varies depending on the extent to which the electrode slurry spreads (sliding length). When the spreading extent of the electrode slurry is small, the sliding length that reduces the edge thickness becomes shorter, forming an area thicker than the average thickness. This increases the risk of breakage caused by the side ring during electrode roll winding and increases the risk of N/P ratio reversal. Conversely, when the spreading extent of the electrode slurry is large, the sliding length increases, reducing the edge thickness. As a result, the capacity decreases proportionally to the lengthening of the sliding part, and there is a risk of lithium precipitation due to air traps. As such, various aspects of the electrode, including capacity, safety, and lifespan, are significantly influenced by the sliding length of the electrode slurry. To control this, a technique involving the simultaneous discharge of insulating solution to the edge of the electrode slurry can be applied. The insulating solution acts as a dam to control the amount of electrode slurry spreading, and by adjusting the discharge volume and width of the insulating solution, the electrode slurry can be controlled to spread to an appropriate level. The electrode slurry and insulating solution are simultaneously discharged onto the moving electrode, and for this purpose, the shim member of the slot die coater is equipped with an insulating solution flow path. For example, the shim member may be composed of two types: a body shim and a spacer shim, with a plurality of spacer shims disposed in the inner void area of the body shim. The space between the spacer shims forms the discharge slots for the electrode slurry, while the insulating solution is discharged through the concave insulating solution flow path formed on the surface of the spacer shim. In the structure of this slot die coater, the amount of insulating solution discharged is determined by the insulating solution flow path formed on the spacer shim. Therefore, to adjust or change the amount of insulating solution discharged, the slot die coater must be disassembled and a new spacer shim with different specifications should be installed. Adjusting the insulating solution discharge volume through the replacement of the spacer shim is cumbersome because various specifications of the spacer shim should be prepared in advance, requiring careful design, manufacturing, and management of the spacer shim. [Summary] [Technical Problem] The present disclosure aims to provide a slot die coater that can easily control the discharge volume of the insulating solution by adjusting the position of the spacer shim without replacing the shim member of the slot die coater. However, the technical problems addressed by the present disclosure are not limited to the above-mentioned problems, and other problems not mentioned herein will be clearly understood by those skilled in the art from