EP-4737017-A1 - DUAL-SLOT DIE COATER

EP4737017A1EP 4737017 A1EP4737017 A1EP 4737017A1EP-4737017-A1

Abstract

Disclosed herein relates to a dual layer slot die coater including: a first die block equipped with a first manifold for accommodating an electrode slurry; a middle block coupled to the first die block; a first coater shim that forms a first electrode slurry slot for discharging an electrode slurry filled in the first manifold, which is interposed between the first die block and the middle block in a shape that wraps around both sides and a rear surface of the first manifold; a second die block that is coupled to the middle block and equipped with a second manifold for accommodating an electrode slurry; and a second coater shim that forms a second electrode slurry slot for discharging an electrode slurry filled in the second manifold, which is interposed between the second die block and the middle block in a shape that wraps around both sides and the rear surface of the second manifold, wherein the first coater shim and the second coater shim each include a first insulating solution flow path and a second insulating solution flow path forming a first insulating solution slot and a second insulating solution slot for discharging insulating solution, respectively, wherein an insulating solution supply flow path for supplying insulating solution to the first insulating solution flow path and the second insulating solution flow path is formed by penetrating the middle block.

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: 20250421

Claims (10)

A dual layer slot die coater comprising: a first die block equipped with a first manifold for accommodating an electrode slurry; a middle block coupled to the first die block; a first coater shim that forms a first electrode slurry slot for discharging an electrode slurry filled in the first manifold, which is interposed between the first die block and the middle block in a shape that wraps around both sides and a rear surface of the first manifold; a second die block that is coupled to the middle block and equipped with a second manifold for accommodating an electrode slurry; and a second coater shim that forms a second electrode slurry slot for discharging an electrode slurry filled in the second manifold, which is interposed between the second die block and the middle block in a shape that wraps around both sides and the rear surface of the second manifold, wherein the first coater shim and the second coater shim each include a first insulating solution flow path and a second insulating solution flow path forming a first insulating solution slot and a second insulating solution slot for discharging insulating solution, respectively, wherein an insulating solution supply flow path for supplying insulating solution to the first insulating solution flow path and the second insulating solution flow path is formed by penetrating the middle block.
The dual layer slot die coater of claim 1, wherein the insulating solution supply flow path comprises: a main flow path penetrating the middle block transversely along a longitudinal direction of the middle block, and a branch flow path that branches from the main flow path and penetrates the middle block along a vertical direction of the middle block.
The dual layer slot die coater of claim 2, wherein both ends of the branch flow path are connected to closed ends of the first insulating solution flow path and the second insulating solution flow path, respectively.
The dual layer slot die coater of claim 3, wherein the first insulating solution flow path is formed concavely on one side surface of the first coater shim that is in close contact with the middle block.
The dual layer slot die coater of claim 4, wherein the second insulating solution flow path is formed concavely on one side surface of the second coater shim that is in close contact with the middle block.
The dual layer slot die coater of any one of claims 1 to 5, wherein the first coater shim comprises: a first body shim that wraps around both sides and the rear surface of the first manifold, and a plurality of first spacer shims spaced apart between the first body shims to traverse toward a front surface of the first manifold, with the first insulating solution flow paths formed on the surfaces of the plurality of first spacer shims.
The dual layer slot die coater of claim 6, wherein the second coater shim comprises: a second body shim that wraps around both sides and the rear surface of the second manifold, and a plurality of second spacer shims spaced apart between the second body shims to traverse toward the front surface of the second manifold, with the second insulating solution flow paths formed on the surfaces of the plurality of second spacer shims.
The dual layer slot die coater of any one of claims 2 to 5, wherein one end of the main flow path is an insulating solution inlet and the other end is closed.
The dual layer slot die coater of any one of claims 2 to 5, wherein both ends of the main flow path are insulating solution inlets.
The dual layer slot die coater of claim 1, wherein the first manifold and the second manifold are each configured to receive a different electrode slurry.

Description

[Technical Field] The present disclosure relates to a dual layer slot die coater, and more specifically to a dual layer slot die coater that efficiently instantiates an insulating solution flow path structure in which an insulating solution simultaneously discharged with an electrode slurry is supplied to the lower layer and/or upper layer. This application claims the benefit of Korean Patent Application No. 10-2024-0055122, filed on April 25, 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 large-scale devices such as battery packs or power storage devices for hybrid vehicles or electric vehicles. In particular, with growing concern about environmental issues, research on electric vehicles and hybrid vehicles, which can replace fossil fuel-powered vehicles such as gasoline and diesel vehicles-a major cause of air pollution-has been actively conducted. Generally, lithium secondary batteries consist of an electrode assembly made up of a positive electrode, a negative electrode, and a separator, which are immersed in a lithium electrolyte. An electrode is formed by coating an electrode slurry including the electrode 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 disposed 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 members, 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 during electrode roll winding due to the side ring and the reversal of the N/P ratio. 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 region, 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 on the edge side 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 over 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 hollow area inside 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 shims. The slot die coater has recently evolved into a dual layer slot die coater (Dual Layer Slot Die Coater, DLD). The Dual Layer Slot Die Coater is a slot die coater that simultaneously discharges electrode slurry in two layers. By varying the series and composition of the lower layer electrode slurry, which directly contacts the electrode, and the upper layer electrode slurry, which is stacked above the lower layer electrode slurry, the performance of secondary batteries can be significantly improved. For example, the lower layer electrode slurry can be formulated with a composition that has excellent adhesion to the electrode, while the upper layer electrode slurry can be formulated with a composition that has excellent electrolyte penetration. By applying these different electrode slurries, it is possible to improve parameters such as charge capacity and charging speed. In a dual layer slot die coater, a technology that simultaneously discharges electrode slurry and insulating solution can be applied to control the sliding phenomenon of the electrode slurry. However, due to the multi-layer structure of the dual layer slot