Patent Description:
The present invention relates to a die coater shim and die coater for effectively and simultaneously coating an electrode slurry and an insulating coating liquid on a current collector for a secondary battery.

With the development of technology and an increase in demand for mobile devices, the demand for secondary batteries is also rapidly increasing. Among secondary batteries, lithium secondary batteries are widely used as an energy source of various electronic products as well as various mobile devices due to having high energy density and high operating voltage and being excellent in terms of preservation and lifespan.

An electrode in which an active material layer and an insulating layer are formed on a surface of a current collector is used in a lithium secondary battery or the like. Such an electrode is manufactured by applying both an electrode slurry including an active material or the like and an insulating coating liquid including an insulating material or the like on a surface of a current collector using a coating apparatus such as a die coater so that the electrode slurry and the insulating coating liquid overlap with a portion of a corner of an electrode mixture layer and drying the electrode slurry and the insulating coating liquid.

<FIG> illustrates a conventional die coater <NUM> for applying an electrode slurry. The die coater <NUM> includes an upper block <NUM> and a lower block <NUM>, a die coater shim <NUM> is interposed between the upper block <NUM> and the lower block <NUM>, and the upper block <NUM>, the lower block <NUM>, and the die coater shim <NUM> are fastened using a plurality of bolt members and coupled to each other. A manifold <NUM> configured to accommodate a certain volume of electrode slurry is provided in the lower block <NUM>, and the manifold <NUM> communicates with an external electrode slurry supply (not illustrated).

Here, the die coater shim simultaneously serves to form a slit of a suitable height between the upper block and the lower block, limit a flowing direction of an electrode slurry so that the electrode slurry is discharged toward the slit, and perform sealing so that the electrode slurry does not leak to portions other than the slit. The die coater shim has guides protruding from both ends thereof in a width direction, and a distance between the guides determines a width at which the electrode slurry is applied on a current collector.

An insulating coating liquid is applied on both corners in the width direction of the electrode slurry applied on the current collector. Generally, applying the insulating coating liquid is performed as an additional process using a separate apparatus after applying the electrode slurry on the current collector. Applying the electrode slurry and the insulating coating liquid on the current collector through separate processes in this way is undesirable in terms of production efficiency.

In order to address such a problem, a technology that forms independent slits, each discharging an electrode slurry and an insulating coating liquid, in a single die coater shim has been introduced, but there is a problem that, in a case in which any one solution leaks in the die coater, the two solutions (the electrode slurry and the insulating coating liquid) are mixed, or the two solutions are mixed and discharged from an outlet of the slit, which may cause poor quality of a current collector.

<CIT>, <CIT>, <CIT> and <CIT> disclose electrode coating devices.

An object of the present invention is to provide a die coater shim and die coater for simultaneously and effectively coating an electrode slurry and an insulating coating liquid on a current collector for a secondary battery.

A die coater shim and die coater for simultaneously and effectively coating an electrode slurry and an insulating coating liquid are provided. The die coater shim according to the present invention includes: a base configured to extend in a width direction; first and second guides configured to protrude and extend from both ends of the base; an electrode slurry slit including a step portion configured to extend from the base in the width direction between the first and second guides, wherein a thickness of the step portion is smaller than a thickness of the base, and a stepped space that the step portion forms relative to one surface of the base forms an electrode slurry discharge path; and first and second insulating coating liquid slits including a groove formed on a surface of each of the first and second guides that corresponds to the other surface of the base, wherein one end of the groove forms an insulating coating liquid discharge path.

In a specific embodiment, the step portion may extend to a partial area in the width direction between the first and second guides.

Also, the one end of the groove that forms an outlet of the first and second insulating coating liquid slits may extend to protruding end portions of the first and second guides.

In a specific embodiment, the one end of the groove may be spaced apart from inner corners of the first and second guides that face each other.

In another embodiment, the die coater shim may further include a third guide positioned between the first and second guides and configured to protrude and extend from the base, the step portion may be formed of a first step portion disposed between the first and third guides and a second step portion disposed between the third and second guides, the electrode slurry slit may be formed of a first electrode slurry slit configured to form a first electrode slurry discharge path using the first step portion and a second electrode slurry slit configured to form a second electrode slurry discharge path using the second step portion, and the die coater shim may further include third and fourth insulating coating liquid slits including a pair of grooves formed on a surface of the third guide that corresponds to the other surface of the base, wherein one end of each of the pair of grooves forms an insulating coating liquid discharge path.

In a specific embodiment, outlets of the third and fourth insulating coating liquid slits may face the first and second guides.

Further, widths of the first and second step portions may be equal to each other.

Meanwhile, an aspect of the present invention provides a die coater including: an upper block in which an insulating coating liquid inlet is provided; a lower block coupled to the upper block and in which a manifold configured to accommodate an electrode slurry is provided; and a die coater shim interposed between the upper block and the lower block to form a slit and configured to simultaneously discharge an insulating coating liquid and the electrode slurry through the slit, wherein the die coater shim has an electrode slurry discharge path formed on one surface and an insulating coating liquid discharge path formed on the other surface opposite to the one surface, and the electrode slurry discharge path and the insulating coating liquid discharge path are physically separated from each other on the die coater shim.

In one embodiment, the die coater shim may include: a base configured to extend in a width direction; first and second guides configured to protrude and extend from both ends of the base; an electrode slurry slit including a step portion configured to extend from the base in the width direction between the first and second guides, wherein a thickness of the step portion is smaller than a thickness of the base, and a stepped space that the step portion forms relative to one surface of the base forms an electrode slurry discharge path; and first and second insulating coating liquid slits including a groove formed on a surface of each of the first and second guides that corresponds to the other surface of the base, wherein one end of the groove forms an insulating coating liquid discharge path.

Further, the step portion may extend to a partial area in the width direction between the first and second guides.

In a specific embodiment, a boundary between the base and the step portion may coincide with a rear end of the manifold provided in the lower block, and an end portion of the step portion may coincide with a front end of the manifold or protrude from the front end of the manifold.

For example, the end portion of the step portion may protrude <NUM> or less from the front end of the manifold.

In another embodiment, the one end of the groove that forms an outlet of the first and second insulating coating liquid slits may extend to protruding end portions of the first and second guides.

A die coater shim of the present invention is configured to simultaneously discharge an insulating coating liquid and an electrode slurry, and in particular, an electrode slurry discharge path and an insulating coating liquid discharge path are physically separated from each other on the die coater shim.

Accordingly, the die coater shim of the present invention effectively prevents the electrode slurry and the insulating coating liquid from being mixed with each other even when the electrode slurry and/or the insulating coating liquid leak inside a die coater.

Therefore, the present invention allows an electrode slurry and an insulating coating liquid to be simultaneously and effectively coated on a current collector for a secondary battery.

Advantageous effects of the present invention are not limited to those mentioned above, and other unmentioned advantageous effects should be clearly understood by those of ordinary skill in the art from the detailed description below.

Since various modifications may be made to the present invention and the present invention may have various embodiments, specific embodiments will be described in detail below.

However, this does not limit the present invention to the specific embodiments, and all modifications, equivalents, or substitutes included in the technical scope of the present invention should be understood as belonging to the present invention, which is defined by the appended claims.

In the present disclosure, terms such as "include" or "have" should be understood as specifying that features, numbers, steps, operations, elements, components, or combinations thereof are present and not as precluding the possibility of the presence or addition of one or more other features, numbers, steps, operations, elements, components, or combinations thereof in advance.

Also, in the present disclosure, when a part such as a layer, a film, an area, or a plate is described as being "on" another part, this includes not only a case where the part is "directly on" the other part, but also a case where still another part is present therebetween. On the contrary, when a part such as a layer, a film, an area, or a plate is described as being "under" another part, this includes not only a case where the part is "directly under" the other part, but also a case where still another part is present therebetween. Also, in the present application, being disposed "on" may include not only being disposed on an upper portion, but also being disposed on a lower portion.

The present Invention provides a die coater shim and die coater for simultaneously and effectively coating an electrode slurry and an insulating coating liquid.

In one embodiment, a die coater shim according to the present invention includes: a base configured to extend in a width direction; first and second guides configured to protrude and extend from both ends of the base; an electrode slurry slit including a step portion configured to extend from the base in the width direction between the first and second guides, wherein a thickness of the step portion is smaller than a thickness of the base, and a stepped space that the step portion forms relative to one surface of the base forms an electrode slurry discharge path; and first and second insulating coating liquid slits including a groove formed on a surface of each of the first and second guides that corresponds to the other surface of the base, wherein one end of the groove forms an insulating coating liquid discharge path.

In particular, since the die coater shim according to the present invention has the electrode slurry discharge path formed on one surface and the insulating coating liquid discharge path formed on the other surface opposite to the one surface, the die coater shim can simultaneously apply an electrode slurry and an insulating coating liquid on a current collector. Further, since the electrode slurry discharge path and the insulating coating liquid discharge path are physically separated from each other on the die coater shim, even when any one solution leaks in a die coater, the two solutions are prevented from being mixed with each other.

Hereinafter, a die coater shim and die coater for simultaneously and effectively coating an electrode slurry and an insulating coating liquid on a current collector for a secondary battery according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<FIG> is a view illustrating a structure of a die coater <NUM> including a die coater shim <NUM> according to an embodiment of the present invention. The overall configuration of the die coater <NUM> and the die coater shim <NUM> will be described in detail below with reference to <FIG>.

The die coater <NUM> includes an upper block <NUM> and a lower block <NUM>, and the die coater shim <NUM> is interposed between the upper block <NUM> and the lower block <NUM>.

The upper block <NUM> and the lower block <NUM> are parts constituting a body of the die coater <NUM>, an insulating coating liquid inlet <NUM> is provided in the upper block <NUM>, and a manifold <NUM> configured to accommodate an electrode slurry supplied from an outside is provided in the lower block <NUM>.

The die coater shim <NUM> is interposed between the upper block <NUM> and the lower block <NUM> to form a slit having a height suitable for discharging the electrode slurry. Also, the die coater shim <NUM> serves to limit a flowing direction of the electrode slurry so that the electrode slurry is discharged toward the slit without flowing backward and serves to perform sealing so that the electrode slurry does not leak to portions other than the slit.

As illustrated in <FIG>, the die coater shim <NUM> has guides <NUM> and <NUM> protruding from both ends thereof in a width direction, and a distance between the guides <NUM> and <NUM> determines a width at which the electrode slurry is applied on a current collector.

The die coater shim <NUM> of the present embodiment is the same as the related art in that a slit for discharging an electrode slurry is formed therein but is different from the related art in that the die coater shim <NUM> of the present embodiment is configured to simultaneously discharge an insulating coating liquid and an electrode slurry.

In particular, the die coater shim <NUM> of the present embodiment has an electrode slurry discharge path formed on the bottom surface of the base and an insulating coating liquid discharge path formed on the top surface of the base, and the electrode slurry discharge path and the insulating coating liquid discharge path are physically separated from each other on the die coater shim <NUM>. Since the electrode slurry discharge path and the insulating coating liquid discharge path are physically separated in this way, even when any one liquid (the electrode slurry and/or the insulating coating liquid) leaks inside the die coater <NUM>, the one liquid is effectively prevented from being mixed with the other liquid.

A specific configuration of the die coater shim <NUM> of the present embodiment will be described in detail with reference to <FIG>. <FIG> shows cross-sectional views taken along lines "A-A" and "B-B" of <FIG> in a state in which the die coater <NUM> of <FIG> is assembled, <FIG> is a front view of the die coater <NUM> of <FIG> in the state in which the die coater <NUM> is assembled, and <FIG> is a plan view illustrating a specific structure of the die coater shim <NUM> illustrated in <FIG>.

First, referring to <FIG>, the die coater shim <NUM> includes a base <NUM> configured to extend in the width direction and the first and second guides <NUM> and <NUM> configured to protrude and extend from both ends of the base <NUM>, and such a structure corresponds to the related art shown in <FIG>.

Here, the die coater shim <NUM> of the present embodiment includes a step portion <NUM> configured to extend from the base <NUM> in the width direction between the first and second guides <NUM> and <NUM>. A thickness of the step portion <NUM> is smaller than a thickness of the base <NUM>, and accordingly, the step portion <NUM> forms a stepped space relative to one surface of the base <NUM> (a surface thereof facing the lower block). As shown in the "A-A" section of <FIG> and the front view of <FIG>, the space that the step portion <NUM> forms communicates with the lower block <NUM> in which the manifold <NUM> is formed. Thus, the step portion <NUM> forms an electrode slurry slit <NUM> that forms a discharge path for the electrode slurry accommodated in the manifold <NUM>.

Also, the first and second guides <NUM> and <NUM> each include a groove <NUM> formed in a surface corresponding to the other surface of the base <NUM> (a surface thereof facing the upper block), and as one end of each groove <NUM> forms an insulating coating liquid discharge path, first and second insulating coating liquid slits <NUM> and <NUM> are provided on the first and second guides <NUM> and <NUM>. Referring to the "B-B" section of <FIG> and the front view of <FIG>, the first and second insulating coating liquid slits <NUM> and <NUM> are formed toward the upper block <NUM>, and accordingly, the electrode slurry slit <NUM> and the first and second insulating coating liquid slits <NUM> and <NUM> are physically separated from each other.

That is, upper and lower surfaces of the first and second guides <NUM> and <NUM> around the first and second insulating coating liquid slits <NUM> and <NUM> are in close contact with the upper block <NUM> and the lower block <NUM>, and thus, along with the upper block <NUM>, the first and second insulating coating liquid slits <NUM> and <NUM> form independent insulating coating liquid discharge paths isolated from surroundings thereof.

Also, the electrode slurry slit <NUM> is formed by the space that the step portion <NUM> between the first and second guides <NUM> and <NUM> forms, and accordingly, the electrode slurry discharge path is separated from the first and second guides <NUM> and <NUM> due to the step portion <NUM> and the lower block <NUM>.

Therefore, since, inside the die coater <NUM>, the first and second insulating coating liquid slits <NUM> and <NUM> are disposed toward the upper block <NUM>, and the electrode slurry discharge path is disposed toward the lower block <NUM> and spatially separated, even when any one solution (the electrode slurry and/or the insulating coating liquid) leaks inside the die coater <NUM>, mixing of the two solutions hardly occurs.

In an embodiment of the present invention, the step portion <NUM> may extend to a partial area in the width direction between the first and second guides <NUM> and <NUM>. It is necessary for the step portion <NUM> to have a certain length because the step portion <NUM> serves to effectively separate the first and second guides <NUM> and <NUM> from the manifold <NUM> of the lower block <NUM>. However, the length of the step portion <NUM> being too long may adversely affect a flow profile in the electrode slurry discharge path. For example, air bubbles may be present due to a vortex when the electrode slurry is discharged. Thus, there is a need to appropriately design the length of the step portion <NUM>.

In a specific embodiment, a boundary between the base <NUM> and the step portion <NUM> may coincide with a rear end (a left side end in the "A-A" section of <FIG>) of the manifold <NUM> provided in the lower block <NUM> to ensure tight sealing of the manifold <NUM>, and an extending end portion of the step portion <NUM> may at least coincide with a front end of the manifold <NUM> or protrude from the front end of the manifold <NUM>. For example, the extending end portion of the step portion <NUM> may protrude <NUM> or less from the front end of the manifold <NUM>.

Also, the one end of the groove <NUM> that forms an outlet of the first and second insulating coating liquid slits <NUM> and <NUM> may extend to protruding end portions of the first and second guides <NUM> and <NUM>. Such a configuration is shown in the "B-B" section of <FIG>. Accordingly, the outlet of the first and second insulating coating liquid slits <NUM> and <NUM> is positioned at a sharp end portion of the die coater <NUM>.

Also, in a specific embodiment, the one end of the groove <NUM> may be spaced apart from inner corners of the first and second guides <NUM> and <NUM> that face each other. A distance at which the one end of the groove <NUM> that forms the outlet of the first and second insulating coating liquid slits <NUM> and <NUM> is spaced apart from the inner corners of the first and second guides <NUM> and <NUM> corresponds to a distance at which the one end is spaced apart from both ends of an electrode slurry discharge width defined by the inner corners of the first and second guides <NUM> and <NUM>. This is to, when an electrode slurry and an insulating coating liquid are simultaneously discharged, prevent the insulating coating liquid, which has slight fluidity, from being immediately mixed with a corner of the discharged electrode slurry. In this way, the edge of the electrode slurry is effectively protected by the insulating coating liquid. Simultaneously applying an electrode slurry B and an insulating coating liquid C on a current collector A using the die coater <NUM> of the present invention is shown in <FIG>.

A second embodiment of the present invention is an embodiment suitable for a case in which an electrode slurry and an insulating coating liquid are applied in two or more rows on a current collector supplied in the form of a coil and then slitting is performed.

That is, the second embodiment corresponds to an embodiment suitable for simultaneously applying an active material coating, which is formed of an "insulating coating liquid-electrode slurry-insulating coating liquid" structure, in two or more rows on a current collector.

In the second embodiment, there is no significant change in the configuration of the upper block <NUM> and the lower block <NUM> constituting the die coater <NUM>, and a main difference is in the die coater shim <NUM>. However, since additional insulating coating liquid slits <NUM> and <NUM> are present in the die coater shim <NUM> of the second embodiment, an additional insulating coating liquid inlet <NUM> corresponding thereto may be required in the upper block <NUM>.

The configuration of the die coater shim <NUM> according to the second embodiment is shown in <FIG>, and the second embodiment will be described focusing on the differences from the first embodiment described above.

Referring to <FIG>, the die coater shim <NUM> of the second embodiment further includes a third guide <NUM> positioned between the first and second guides <NUM> and <NUM> and configured to protrude and extend from an intermediate portion of the base <NUM>.

Also, as the third guide <NUM> is provided on the intermediate portion of the base <NUM>, the step portion <NUM> is separated into a first step portion <NUM> disposed between the first guide and the third guide <NUM> and a second step portion <NUM> disposed between the third and second guides. Also, corresponding thereto, the electrode slurry slit <NUM> is divided into a first electrode slurry slit <NUM> configured to form one electrode slurry discharge path using the first step portion <NUM> and a second electrode slurry slit <NUM> configured to form another electrode slurry discharge path using the second step portion <NUM>.

Also, a pair of grooves <NUM> are formed on a surface of the third guide <NUM> that corresponds to the other surface of the base <NUM> (the surface thereof facing the upper block), and one ends of the pair of grooves <NUM> constitute third and fourth insulating coating liquid slits <NUM> and <NUM> that form additional insulating coating liquid discharge paths.

Referring to <FIG> with reference to the first embodiment, a structure that the first and third guides <NUM> and <NUM> constitute and a structure that the third and second guides <NUM> and <NUM> constitute are symmetrical to each other. That is, the die coater shim <NUM> of the second embodiment may be described as a structure in which two die coater shims <NUM> of the first embodiment are coupled in parallel in a transfer direction of the current collector A (see <FIG>).

Therefore, using the die coater shim <NUM> of <FIG>, an active material may be simultaneously applied in two rows on a current collector in order to be suitable for slitting. In a case in which widths of two rows of electrode slurries are equal to each other, widths of the first and second step portions <NUM> and <NUM> may be made equal to each other. Here, since the width of the insulating coating liquid is almost constant regardless of the width of the electrode slurry, there is no need to significantly change the configuration of the third and fourth insulating coating liquid slits <NUM> and <NUM>.

The present invention has been described in detail above using the drawings, embodiments, or the like. However, configurations illustrated or described in the drawings or embodiments herein are only some embodiments of the present invention.

Claim 1:
A die coater shim (<NUM>) for simultaneously applying an electrode slurry and an insulating coating liquid on a current collector, the die coater shim (<NUM>) comprising:
a base (<NUM>) configured to extend in a width direction;
first and second guides (<NUM>, <NUM>) disposed on each end of the base (<NUM>) in the width direction, wherein the first and second guides (<NUM>, <NUM>) protrude and extend from the base (<NUM>) in a direction orthogonal to the width direction;
characterized in that a first electrode slurry slit (<NUM>) including a first step portion (<NUM>) is disposed between the first and second guides (<NUM>, <NUM>) in the width direction, wherein a thickness of the first step portion (<NUM>) is smaller than a thickness of the base (<NUM>), wherein the thickness of the first step portion (<NUM>) forms a first stepped space relative to a first surface of the base (<NUM>), wherein the first stepped space forms an electrode slurry discharge path; and in that
first and second insulating coating liquid slits (<NUM>, <NUM>) including a groove (<NUM>) are formed on a surface of each of the first and second guides (<NUM>, <NUM>) disposed on a second surface of the base (<NUM>), wherein one end of each of the grooves (<NUM>) forms an insulating coating liquid discharge path.