Slot Die Coater and Electrode Coating Device Including Same

A slot die coater is configured to discharge a coating material onto a surface of a substrate, and may include: a first die having a first surface; a second die having a second surface facing the first surface; and a shim plate interposed between the first surface of the first die and the second surface of the second die to form a slot through which the coating material is discharged. The second die may include a pair of guide lips protruding from both ends of the opening of the slot toward the substrate. An electrode coating device including the slot die coater is configured to coat an electrode substrate using the slot die coater.

TECHNICAL FIELD

The present disclosure relates to a slot die coater and an electrode coating device including the same and, more specifically, relates to a slot die coater that discharges a coating material onto a surface of a substrate through a slot, and an electrode coating device including the same.

BACKGROUND ART

In general, an electrode assembly of a secondary battery capable of being repeatedly charged and discharged is manufactured by stacking or winding multiple layers in a laminated structure in which a separator is interposed between a first electrode corresponding to the positive electrode (cathode) and a second electrode corresponding to the negative electrode (anode). In this case, each electrode is manufactured by applying a slurry coating material containing a positive-electrode active material or a negative-electrode active material onto an electrode substrate made of aluminum or copper and drying the same.

Recently, slot die coaters have been used in the coating process of this electrode substrate. The slot die coater is a device that discharges a coating material through a slot to coat the surface of a substrate to be coated.

However, as disclosed in Korean Unexamined Patent Publication No. 10-2019-0060557, in the existing technology, since pressure is applied to the inside of the slot die coater to discharge a coating material contained inside the slot die coater through an opening of a slot having a relatively large width and a very small height, when applied to an actual coating process, there is a problem in which the width of the discharged coating material expands beyond the width of the slot opening due to discharge pressure and atmospheric pressure, bringing about a result different from the design.

Moreover, the existing technology has a problem in which the width of the discharged coating material becomes uneven due to the pulsation of pressure applied into the slot die coater.

DISCLOSURE

Technical Problem

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to providing a slot die coater capable of preventing a phenomenon in which the width of the coating material discharged onto the surface of the substrate through the slot expands beyond the width of the slot opening due to the discharge pressure and atmospheric pressure and a phenomenon in which the width of the coating material becomes uneven due to the pulsation of discharge pressure, and an electrode coating device including the same.

Technical Solution

A slot die coater according to an embodiment of the present disclosure is a device configured to discharge a coating material onto a surface of a substrate, and may include: a first die having a first surface; a second die having a second surface facing the first surface; and a shim plate interposed between the first surface of the first die and the second surface of the second die to form a slot through which the coating material is discharged, wherein the second die may include a pair of guide lips protruding from both ends of the opening of the slot toward the substrate.

In an embodiment, the pair of guide lips may be configured to come into contact with both side edge portions of the coating material discharged onto the surface of the substrate so as to guide the movement of the coating material according to the movement of the substrate.

In an embodiment, the first die may further include an accommodation groove configured to accommodate the coating material and lead to the slot.

In an embodiment, the first die may include: a body portion having the first surface and the opening located at the front end thereof; and a support portion extending from the rear end of the body portion toward the second die and supporting the second die.

In an embodiment, the first die may include a first die lip protruding toward the substrate so as to form one side wall of the opening.

In an embodiment, the second die may further include a second die lip protruding toward the substrate between the pair of guide lips so as to form the other side wall of the opening, and the pair of guide lips may be configured to protrude more than the second die lip toward the substrate.

In an embodiment, the protruding length of the pair of guide lips toward the substrate may be configured to be greater than that of the second die lip in the range of 100 μm to 300 μm.

In an embodiment, the pair of guide lips and the second die lip may be configured to have a predetermined thickness, respectively, and protrude toward the substrate, and the pair of guide lips may be configured to be thicker than the second die lip.

In an embodiment, the second die may further include a second die lip protruding toward the substrate between the pair of guide lips so as to form the other side wall of the opening, and the first die lip may be configured to protrude more than the second die lip toward the substrate.

In an embodiment, the second die may include: a first die block disposed at a predetermined gap from the first die so as to form the slot; a second die block having a first guide lip among the pair of guide lips and disposed on one side of the first die block; and a third die block having a second guide lip among the pair of guide lips and disposed on the other side of the first die block, and the first die block may include: a first support protrusion protruding from one side of the first die block facing the second die block toward the second die block; and a second support protrusion protruding from the other side of the first die block facing the third die block toward the third die block, and the second die block may further include a first support groove configured to receive the first support protrusion to support the first die block, and the third die block may further include a second support groove configured to receive the second support protrusion to support the first die block.

An electrode coating device according to an embodiment of the present disclosure is a device including the slot die coater according to one of the embodiments described above, and may be configured to coat an electrode substrate using the slot die coater.

Advantageous Effects

According to the present disclosure, a pair of guide lips respectively protruding from both widthwise ends of the opening of the slot toward the substrate to be coated may come into contact with both side edge portions of the coating material discharged onto the surface of the substrate to block the coating material from expanding in the side direction of the coating material and to guide the movement of the coating material according to the movement of the substrate, thereby minimizing the phenomenon in which the width of the discharged coating material expands beyond the width of the slot opening due to the discharge pressure or atmospheric pressure and preventing the phenomenon in which the width of the discharged coating material becomes uneven due to pulsation of the discharge pressure.

In addition, among the two die lips that form the opening of the slot, a first die lip that earlier meets the substrate moving in one direction may be configured to protrude more toward the substrate than the second die lip that later meets the substrate, thereby preventing the coating material discharged through the slot from leaking in the opposite direction of the movement direction of the substrate due to the discharge pressure or atmospheric pressure.

In addition, among the first die and the second die constituting the slot die coater, since the second die having the pair of guide lips may be configured by coupling of a first die block forming the slot together with the first die, a second die block having a first guide lip among the pair of guide lips, and a third die block having a second guide lip among the pair of guide lips, it is possible to easily implement a fine step structure formed between the pair of guide lips and the opening of the slot without precision machining and reduce manufacturing time and manufacturing cost while improving the precision of the slot die coater.

In addition, since a support structure may be provided to support the first die block without using additional fastening members so as to maintain the gap between the first die and the first die block of the second die, even if the slot die coater is manufactured using the second die configured as a combination of die blocks, instead of an integrated block, the durability and reliability of the slot die coater is able to be guaranteed.

Furthermore, those skilled in the art to which the present disclosure pertains will be able to clearly understand from the following description that various embodiments according to the present disclosure can solve various technical problems not mentioned above.

DETAILED DESCRIPTION

Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings to clarify solutions corresponding to the technical problems of the present disclosure. However, in describing the present disclosure, a description of related known technology, which may obscure the subject matter of the present disclosure, may be omitted. In addition, the terms used in this specification are defined in consideration of the functions in the present disclosure and may vary depending on the intention of the designer, manufacturer, etc. or custom thereof. Therefore, definitions of the terms described below should be made based on the description throughout this specification.

Meanwhile, the same reference numerals indicate the same components in the attached drawings. In addition, the components of the present disclosure or parts of each component shown in the attached drawings may be exaggerated, reduced, or simplified in order to effectively explain the technical features of the present disclosure.

FIG.1is a perspective view illustrating a slot die coater10according to an embodiment of the present disclosure.

As shown inFIG.1, the slot die coater10according to an embodiment of the present disclosure may be configured to discharge a coating material through a slot12to the transfer path of a target substrate transferred in one direction by a predetermined transfer means so as to coat the surface of the target substrate. To this end, the slot die coater10may include a first die100, a second die200, and a shim plate300.

The first die100may be configured to have a first surface facing the second die200and to be combined with the second die200to form an accommodation space for accommodating a coating material.

In this case, the first die100may include a body portion110that has the first surface and an opening12aof the slot located at the front end thereof, and a support portion120that extends from the rear end of the body portion110toward the second die200so as to support the second die200. In addition, the body portion110of the first die100may have a first die lip112that protrudes toward the target substrate (X-axis direction) and forms one side wall of the opening12a.

The opening12alocated at the end of the slot12may have a predetermined height and width, but may have a width considerably greater than its height. As will be described again below, the width of the opening12alocated at the end of the slot12may correspond to the width of a coating layer formed on the surface of the substrate.

The second die200may be configured to have a second surface facing the first surface of the first die100and to be combined with the first die100to form the accommodation space for accommodating the coating material.

In addition, the second die200may have a pair of guide lips222and232that respectively protrudes from both widthwise ends of the opening12atoward the target substrate (X-axis direction).

The pair of guide lips222and232may be configured to come into contact with the edge portions of both sides in the width direction of the coating material discharged onto the surface of the target substrate to prevent the coating material from expanding in the edge direction thereof due to discharge pressure or atmospheric pressure and guide the movement of the coating material according to the movement of the target substrate.

In addition, the second die200may include a second die lip212that protrudes toward the target substrate (X-axis direction) between the pair of guide lips222and232so as to form the other side wall of the opening12a.

In this case, the pair of guide lips222and232may be configured to protrude more than the second die lip212toward the target substrate. As will be described again below, the protruding length of the pair of guide lips222and232toward the target substrate may be configured to be greater than that of the second die lip212in the range of 100 μm to 300 μm.

In addition, the first die lip112of the first die100may be configured to protrude more than the second die lip212toward the target substrate. In this case, the protruding length of the first die lip112toward the target substrate may be configured to be greater than that of the second die lip212in the range of 100 μm to 300 μm. Depending on the embodiment, the first die lip112may be configured to protrude by the same length as the second die lip212.

In an embodiment, the second die200may include a first die block210, a second die block220, and a third die block230. The second die200may be formed by coupling of the first die block210, the second die block220, and the third die block230. That is, the second die200may be configured by coupling three die blocks210,220, and230side by side along the width direction of the opening12a.

In this case, the first die block210may include the second die lip212and may be configured to be disposed at a certain gap from the first die100to form the slot12.

The second die block220may include the first guide lip222among the pair of guide lips222and232and may be configured to be disposed on one side of the first die block210.

The third die block230may include the second guide lip232among the pair of guide lips222and232and may be configured to be disposed on the other side of the first die block210.

The first die block210, the second die block220, and the third die block230may be configured to be coupled to the first die100by fastening members214,224, and234, respectively, such as bolts.

As described above, since the second die200constituting the slot die coater10may be configured by coupling of the die blocks210,220, and230each having only one of the guide lip and die lip, it is possible to easily implement a fine step structure formed between the pair of guide lips222and232and the second die lip212without precision machining and reduce manufacturing time and manufacturing cost while improving the precision of the slot die coater.

As will be described again below, the shim plate300may be configured to be interposed between the first surface of the first die100and the second surface of the second die200so as to form the slot12through which the coating material is discharged.

Meanwhile, the substrate to be coated by the slot die coater10may be an electrode substrate used in manufacturing electrodes of secondary batteries. In this case, the electrode substrate may be a metal foil used in manufacturing the positive or negative electrode, or a sheet of PE (polyethylene) or PP (polypropylene) used in manufacturing a separator.

In addition, the coating material discharged from the slot die coater10may be a slurry containing a conductive agent and a binder along with a positive-electrode active material or negative-electrode active material, or may be a coating material containing a ceramic material. In this case, materials such as LiCoO2, LiMn2O4, LiFePO4, LiNiCoAlO2, LiNiMnCoO2, or Li2TiO3may be used as the positive-electrode active material. In addition, materials such as natural graphite, artificial graphite, or low-crystalline carbon may be used as the negative-electrode active material.

FIG.2is an enlarged view illustrating the area M1inFIG.1.

As shown inFIG.2, the first die lip112of the first die100and the second die lip212of the first die block210constituting the second die200may be disposed to have a gap equal to the thickness of the shim plate300therebetween, thereby forming the opening12aof the slot through which the coating material is discharged.

In addition, the first guide lip222of the second die block220disposed on one side of the first die block210may protrude more than the opening12aof the slot or the second die lip212of the first die block210toward the substrate, that is, in the discharge direction of the coating material.

A first step surface provided due to the difference in protruding length between the first guide lip222and the second die lip212serves to guide the movement of the coating material discharged through the opening12aof the slot.

Likewise, a second step surface provided due to the difference in protruding length between the second guide lip232of the second die block220and the second die lip212also serves to guide the movement of the coating material discharged through the opening12aof the slot. In this case, the first step surface of the first guide lip222and the second step surface of the second guide lip232may be configured as planes facing each other in parallel.

In addition, the protruding lengths of the first guide lip222and the second guide lip232may be the same.

FIG.3is an exploded perspective view illustrating the slot die coater10shown inFIG.1.

As shown inFIG.3, the slot die coater10may include a first die100, die blocks210,220, and230, and a shim plate300.

As described above, the first die100may include the body portion110and the support portion120. A first die lip112forming the opening12aof the slot may be provided at the front end of the body portion110, and an accommodation groove116may be provided on the upper surface114of the body portion110facing the die blocks210,220, and230.

The accommodation groove116may be configured to accommodate the coating material and lead to the slot12. This accommodation groove116may serve as a manifold that delivers the coating material to the slot12. To this end, the accommodation groove116may be configured to be connected to a coating material supply chamber (not shown) installed at the outside through a pipe to receive the coating material from the chamber.

Depending on the embodiment, the body portion110may have a fastening groove118through which a predetermined fastening member used to couple the die blocks210,220, and230and the shim plate300to the body portion110is fastened.

The support portion120may be configured to extend upwards from the rear end of the body portion110so as to support the die blocks210,220, and230. In this case, the body portion110and the support portion120may be formed integrally with each other.

The die blocks210,220, and230coupled to the first die100may be configured to have lower surfaces facing the upper surface114of the first die100, respectively, and to be coupled to the first die100to form the accommodation space for accommodate the coating material and the slot12for discharging the coating material.

To this end, the first die block210may include a second die lip212that forms the opening12aof the slot together with the first die lip212of the first die100. Depending on the embodiment, the first die block210may have an insertion hole216into which a fastening member used to couple the first die block210to the first die100is inserted.

In addition, the second die block220may be configured to have a first guide lip222among the pair of guide lips222and232and to be disposed on one side of the first die block210. Depending on the embodiment, the second die block220may have an insertion hole226into which a fastening member used to couple the second die block220to the first die100is inserted.

The third die block230may be configured to have a second guide lip232among the pair of guide lips222and232and to be disposed on the other side of the first die block210. Depending on the embodiment, the third die block230may have an insertion hole236into which a fastening member used to couple the third die block230to the first die100is inserted.

The first die100and the die blocks210,220, and230of the second die200may be made of a material including stainless steel. For example, the first die100and the die blocks210,220, and230of the second die200may be made of a stainless steel material that is easy to process and has high corrosion resistance, such as SUS304, SUS316L, SUS420J2,SUS440C, SUS630, or the like.

The shim plate300may be configured to be interposed between the upper surface of the first die100and the lower surfaces of the die blocks210,220, and230so as to form the slot12through which the coating material is discharged. The shim plate300may determine the shape of the slot12through which the coating material is discharged and serve as a gasket that prevents leakage of the coating material to the outside in portions other than the slot12of the slot die coater10.

To this end, the shim plate300may have a plate structure that entirely covers the upper surface114of the first die100. In addition, the shim plate300may have a hollow310formed in the center thereof so as to correspond to the accommodation groove116of the first die100, and an opening320formed on one side thereof so as to lead to the hollow310.

This shim plate300may determine the shape of the opening12aof the slot through which the coating material is discharged. That is, the thickness Ts of the shim plate300may determine the height of the opening12aof the slot, and the opening width Ws of the shim plate300may determine the width of the opening12aof the slot.

Depending on the embodiment, the shim plate300may have an insertion hole302into which a fastening member used to couple the shim plate300to the first die100is inserted.

FIG.4is a cross-sectional view taken along line A-A′ of the slot die coater10shown inFIG.1.

As shown inFIG.4, the third die block230corresponding to the side portion of the second die200may be coupled to the first die100with the shim plate300interposed therebetween. The guide lip232of the third die block230may protrude toward the substrate (in the X-axis direction). In this case, the die lip112of the first die100may protrude by the same length as the guide lip232of the third die block230.

Depending on the embodiment, the die lip112of the first die100may be configured to protrude by a length shorter than the guide lip232of the die block230.

The second die block220corresponding to the other side portion of the second die200may have a structure corresponding to the third die block230described above.

FIG.5is a cross-sectional view taken along line B-B′ of the slot die coater10shown inFIG.1.

As shown inFIG.5, the first die block210corresponding to the center portion of the second die200may be coupled to the first die100with the shim plate300interposed therebetween so as to form the slot12leading to the accommodation groove116of the first die100.

That is, the rear end of the first die block210may be coupled to and supported by the first die100with the shim plate300interposed therebetween. On the other hand, the front end of the first die block210may be spaced apart from the first die100by a gap corresponding to the thickness of and the shim plate300, thereby forming the slot12.

Meanwhile, the die lip112of the first die100and the die lip212of the die block210may form the opening12aof the slot. As described above, the height of the opening12amay correspond to the thickness of the shim plate300, and the width of the opening12amay correspond to the width of the opening320provided in the shim plate300.

The movement of the coating material discharged through the opening12aof the slot formed above may be guided by the guide lips222and232protruding from both widthwise ends of the opening12a,respectively.

FIG.6is an enlarged view illustrating the area M2inFIG.5.

As shown inFIG.6, the first die lip112provided in the first die100and the second die lip212provided in the first die block210among the die blocks210,220, and230of the second die200may form the opening12aof the slot through which the coating material is discharged.

In this case, the length L1of the first die lip112may be configured to be greater than the length L2of the second die lip212. In another embodiment, the length L1of the first die lip112may be configured to be the same as the length L2of the second die lip212.

Meanwhile, the first guide lip222of the second die block220may have a predetermined thickness and protrude from the opening12atoward the substrate by a predetermined length Lg. That is, the first guide lip222may protrude more than the second die lip212, which determines the position of the opening12a,toward the substrate. In other words, the second die lip212may be configured to be shorter than the first guide lip222.

In this case, the length difference (Lg−L2) between the guide lip222and the second die lip212may be determined in the range of 100 μm to 300 μm.

If the length difference (Lg−L2) is less than 100 μm, both side edges of the coating material discharged onto the surface of the target substrate may be mostly exposed to the atmosphere without coming into contact with the first guide lip222, so the width of the discharged coating material may expand more than the width of the opening12aand become uneven.

On the other hand, if the length difference (Lg−L2) exceeds 300 μm, since the opening12amust be spaced from the target substrate by a certain distance or more to ensure a minimum gap between the first guide lip222and the target substrate, it is difficult to control the thickness of the coating layer formed on the target substrate.

A coating gap refers to the distance between the end of the die lip and the substrate. This coating gap influences the pressure of the coating bead during coating, thereby affecting the coating width. If the coating gap changes, the width of both side edges of the coating material changes until it reaches an equilibrium with atmospheric pressure.

In the present disclosure, since the second die lip212is shorter than the first guide lip222, the coating gap at the end of the first guide lip222is smaller than the coating gap at the end of the second die lip212. Accordingly, the edge portion of the coating material in contact with the first guide lip222has a smaller surface area in contact with air and becomes insensitive to pressure changes. As a result, deformation of the edge portion in contact with the first guide lip222may be reduced, and uniformity of the overall coating width may be secured.

The protruding lengths of the first guide lip222and the second guide lip232may be the same. Therefore, the effect of uniform coating width due to the difference in length between the first guide lip222and the second die lip212is the same even between the second guide lip232and the second die lip212.

Meanwhile, although the length Lg of the first guide lip222and the length L1of the first die lip112are illustrated as being the same or similar to each other inFIG.6, depending on the embodiment, the first guide lip222may be configured to have a length Lg greater than the length L1of the first die lip112. In this case, the length difference (Lg−L2) between the first guide lip222and the first die lip112may be determined in the range of 100 μm to 300 μm.

FIG.7is a cross-sectional view illustrating the lip structure of a slot die coater according to a modified embodiment of the present disclosure.

As shown inFIG.7, the guide lip222′ may have a predetermined thickness Tg and protrude toward the substrate. In addition, the second die lip212may also have a predetermined thickness Td and protrude toward the substrate. In this case, the guide lip222′ may be configured to be thicker than the second die lip212.

As will be described again below, the coating material discharged onto the surface of the target substrate through the opening12aof the slot moves in the thickness direction of the guide lip222′ (e.g., the upward direction inFIG.7) along the target substrate. Accordingly, as the thickness Tg of the guide lip222′ increases, the distance over which the discharged coating material is guided by the guide lip222′ increases. As a result, the effect of the guide lip222′ preventing the discharged coating material from spreading in the width direction (both side directions) and making the edges of the discharged coating material uniform while guiding the movement of the discharged coating material may be further improved.

FIG.8is a diagram illustrating the coating method of a slot die coater according to an embodiment of the present disclosure.

As shown inFIG.8, the coating material C discharged onto the surface of the substrate E through the opening12aof the slot may expand in the width direction (or the direction of CD) of the substrate E or coating material C, which intersect the movement direction (or the direction of MD) of the substrate E, due to discharge pressure and atmospheric pressure.

In this case, the guide lip222may guide the movement of the coating material C according to the movement of the target substrate E while blocking the expansion of the discharged coating material C. Therefore, it is possible to prevent the coating width from changing. In addition, since the coating material C forms a coating bead after being guided by the guide lip222, instead of spreading immediately after leaving the opening12aof the slot, it is possible to alleviate sliding in which the edge portions of the coating material collapse and form a gentle boundary surface, and the reproducibility of sliding is also increased.

Meanwhile, the coating material C discharged onto the surface of the target substrate E through the opening12aof the slot may leak in the opposite direction of the movement direction of the target substrate E due to the discharge pressure and atmospheric pressure. This instability in which some of the coating material is lost upstream from the outside of the die lip is referred to as leaking. This leaking indicates loss of pre-metered coating material, which makes the final coating thickness unpredictable. This leaking may cause the coating material to remain for a long period of time and solidify, or cause a difference in the coating thickness in the width direction. In particular, when the coating material is ejected at high pressure for the purpose of thin film coating or in the state in which the coating gap is lowered to hundreds of um to reduce the thickness difference in the width direction of the coating layer, the above-described leaking may become worse.

In this case, the first die lip112protruding from the opening12aof the slot toward the substrate E may come into contact with the discharged coating material C to prevent the coating material C from leaking in the opposite direction. Accordingly, it is possible to minimize the occurrence of licking and prevent the coating width from becoming uneven due to pulsation of discharge pressure, and the reproducibility of sliding with respect to the edge portion of the coating material also increases.

FIG.9is a diagram illustrating a coating layer formed by a general slot die coater20.

As shown inFIG.9, the width Wc1of the coating material C discharged onto the surface of the substrate E through the slot22of a general slot die coater20expands wider than the opening width Ws1of the slot22due to discharge pressure or atmospheric pressure, bringing about a different result from the design intention.

Moreover, the width Wc1of the coating material C is formed non-uniformly depending on the pulsation of the pressure for discharging the coating material C.

FIG.10is a diagram illustrating a coating layer formed by a slot die coater10according to an embodiment of the present disclosure.

As shown inFIG.10, the slot die coater10according to an embodiment of the present disclosure includes a pair of guide lips222and232that has a predetermined thickness and protrudes from both ends of the opening12aof the slot toward the substrate E.

The pair of guide lips222and232comes into contact with both side edge portions of the coating material C discharged onto the surface of the substrate E to block the coating material C from expanding in the width direction thereof (or the direction of CD). As a result, the difference between the width Ws2of the opening12aof the slot and the width Wc2of the coating material C discharged through the opening12amay be minimized.

In addition, the pair of guide lips222and232may guide the movement of the coating material C through step surfaces facing each other in parallel, thereby making the edges of the coating material C uniform. As a result, it is possible to prevent the width Wc2of the coating material C from becoming uneven due to pulsation of the pressure for discharging the coating material C.

As described above, the slot die coater10according to the present disclosure may be insensitive to factors that cause changes in coating width, compared to the conventional slot die coater, thereby performing the coating process without a change in the coating width.

FIG.11is a diagram illustrating a second die200′ of a slot die coater according to a modified embodiment of the present disclosure.

As shown inFIG.11, the second die200′ of a slot die coater according to a modified embodiment of the present disclosure may include a first die block210′ forming the center portion thereof, and a second die block220′ and a third die block230′ forming side portions thereof.

In this case, the first die block210′ may include a first support protrusion218aprotruding from one side facing the second die block220′ toward the second die block220′, and a second support protrusion218bprotruding from other side facing the third die block230′ toward the third die block230′.

The second die block220′ may have a first support groove228configured to receive the first support protrusion218aof the first die block210′ so as to support the first die block210′.

The third die block230′ may have a second support groove238configured to receive the second support protrusion218bof the first die block210′ so as to support the first die block210′.

As described above, the supporting structures218a,218b,228, and238supporting the first die block210′ may be provided to maintain the gap between the first die100and the first die block210′ of the second die200′ without using additional fastening members, thereby ensuring durability and reliability of the slot die coater even if the slot die coater is manufactured using the second die200′ configured by a combination of die blocks, instead of an integral block.

FIG.12is a diagram illustrating an electrode coating device400according to an embodiment of the present disclosure.

As shown inFIG.12, the electrode coating device400may be configured to include a slot die coater10according to an embodiment of the present disclosure and coat the surface of the electrode substrate using the slot die coater10.

To this end, the electrode coating device400may further include a transfer unit410, a drying unit420, and a control unit430.

The transfer unit410may be configured to transfer an electrode substrate E to be used in electrode manufacturing to the drying unit420via the slot die coater10. To this end, the transfer unit410may include an unwinder412, a transfer roll414, a rolling roll416, and a rewinder418.

The unwinder412may be configured to unwind and move the electrode substrate E that is generally wound in a roll shape. In this case, the unwinder412may include a wheel on which the electrode substrate E wound in a roll is fixed, and a motor (not shown) that rotates the wheel at a predetermined direction and speed to unwind the electrode substrate E fixed on the wheel. In this specification, the “electrode substrate” may indicate various sheets used in manufacturing electrode assemblies of secondary batteries, such as sheets for manufacturing positive electrodes, sheets for manufacturing negative electrodes, and sheets for manufacturing separators.

The transfer roll414may be configured to be disposed at various positions of the electrode coating device400to facilitate movement of the electrode substrate E.

The rolling roll416may be configured to roll the electrode substrate E having a coating layer formed thereon and dried by the drying unit420.

The rewinder418may be configured to rewind the rolled electrode substrate E. To this end, the rewinder418may include a wheel for rewinding the rolled electrode substrate E and a motor (not shown) that rotates the wheel at a predetermined direction and speed to rewind the rolled electrode substrate E.

Depending on the embodiment, the electrode coating device400may be configured to perform a slitting process before transferring the electrode substrate E rolled by the rolling roll416to the rewinder418.

Meanwhile, the slot die coater10may apply a coating material onto the surface of the electrode substrate E, which is unwound and transferred by the unwinder412.

The drying unit420may be configured to dry the electrode substrate E onto which the coating material is applied.

To this end, the drying unit420may include a chamber422with an internal space, a heating unit424that provides hot air to the electrode substrate E, and a lamp426that radiates electromagnetic waves in a predetermined wavelength band. In this case, the lamp426may be configured as a MIR (Medium wave Infra-Red) lamp that emits mid-infrared rays in a wavelength band ranging from 1400 nm to 3000 nm.

The control unit430may be configured to control the overall operation of the electrode coating device400. In particular, the control unit430may be configured to control the operation of the heating unit424and the lamp426disposed inside the chamber422of the drying unit420.

To this end, the control unit430may optionally include hardware such as a general-purpose processor for executing control logic, an Application-Specific Integrated Circuit (ASIC), other chipsets, logic circuits, registers, memory, and the like.

In addition, the control unit430may further include a temperature sensor432that measures the temperature inside the chamber422and a gas sensor434that measures the gas concentration inside the chamber422. In this case, the control unit430may control the operation of the heating unit424and the lamp426on the basis of temperature information measured by the temperature sensor432and gas concentration information measured by the gas sensor434.

As described above, according to the present disclosure, a pair of guide lips respectively protruding from both widthwise ends of the opening of the slot toward the substrate to be coated may come into contact with both side edge portions of the coating material discharged onto the surface of the substrate to block the coating material from expanding in the side direction of the coating material and to guide the movement of the coating material according to the movement of the substrate, thereby minimizing the phenomenon in which the width of the discharged coating material expands beyond the width of the slot opening due to the discharge pressure or atmospheric pressure and preventing the phenomenon in which the width of the discharged coating material becomes uneven due to pulsation of the discharge pressure.

In addition, among the two die lips that form the opening of the slot, a first die lip that earlier meets the substrate moving in one direction may be configured to protrude more toward the substrate than the second die lip that later meets the substrate, thereby preventing the coating material discharged through the slot from leaking in the opposite direction of the movement direction of the substrate due to the discharge pressure or atmospheric pressure.

In addition, among the first die and the second die constituting the slot die coater, since the second die having the pair of guide lips may be configured by coupling of a first die block forming the slot together with the first die, a second die block having a first guide lip among the pair of guide lips, and a third die block having a second guide lip among the pair of guide lips, it is possible to easily implement a fine step structure formed between the pair of guide lips and the opening of the slot without precision machining and reduce manufacturing time and manufacturing cost while improving the precision of the slot die coater.

In addition, since a support structure may be provided to support the first die block without using additional fastening members so as to maintain the gap between the first die and the first die block of the second die, even if the slot die coater is manufactured using the second die configured as a combination of die blocks, instead of an integrated block, the durability and reliability of the slot die coater may be guaranteed.

Furthermore, it goes without saying that the embodiments according to the present disclosure are able to solve various technical problems other than those mentioned in this specification in the relevant technical fields as well as this technical field.

So far, the present disclosure has been described with reference to specific embodiments. However, those skilled in the art will clearly understand that various modified embodiments may be implemented within the technical scope of the present disclosure. Therefore, the previously disclosed embodiments should be considered as those intended to describe the present disclosure, instead of those intended to limit the present disclosure. In other words, the true scope of the technical idea of the present disclosure is shown in the claims, and all differences within the scope equivalent thereto should be construed as being included in the present disclosure.