Patent Description:
With the increasing technology development and the growing demand for mobile devices, the demand for secondary batteries as an energy source is rapidly increasing, and a secondary battery essentially includes an electrode assembly which is a power generation element. The electrode assembly includes a positive electrode, a separator and a negative electrode stacked at least once, and the positive electrode and the negative electrode are prepared by coating and drying a positive electrode active material slurry and a negative electrode active material slurry on a current collector made of an aluminum foil and a current collector made of a copper foil, respectively. In general, the secondary battery includes lithium containing cobalt oxide (LiCoO<NUM>) of layered crystal structure, lithium containing manganese oxide, for example, LiMnO<NUM> of layered crystal structure and LiMn<NUM>O<NUM> of spinel crystal structure, and lithium containing nickel oxide (LiNiO<NUM>) for the positive electrode active material. Additionally, a carbon based material is primarily used as the negative electrode active material, and recently, with the growing demand for high energy lithium secondary batteries, the carbon based material may be mixed with a silicon based material or a silicon oxide based material having the effective capacity that is at least <NUM> times larger than the carbon based material. For the uniform charging/discharging characteristics of secondary batteries, it is necessary to uniformly coat the positive electrode active material slurry and the negative electrode active material slurry on the current collector, and slot die coaters have been used.

<FIG> is an exploded cross-sectional view of a conventional slot die coater, and <FIG> is an exploded cross-sectional view of another conventional slot die coater.

Referring to <FIG>, the slot die coater <NUM> includes two die blocks <NUM>, <NUM>, and has a slot <NUM> by a shim <NUM> between the two die blocks <NUM>, <NUM>. An active material slurry in a manifold <NUM> leaves an exit port in communication with the slot <NUM> and is coated on a current collector (not shown).

Referring to <FIG>, the slot die coater <NUM> includes three die blocks <NUM>, <NUM>, <NUM> and a shim <NUM> is positioned every two die blocks to form two slots <NUM>.

<FIG> is a top view of the conventional shim <NUM> that may be applied to the slot die coaters <NUM>, <NUM>.

A coating width of an active material layer coated on the current collector is determined by the width of the slot <NUM> of the slot die coaters <NUM>, <NUM>, and since the slot <NUM> is defined by the shim <NUM>, the width W of the slot <NUM> is determined by the shape of the shim <NUM>. The shim <NUM> shown in <FIG> is configured to coat, for example, a stripe shaped pattern of three lanes.

<FIG> is an enlarged view of section A in <FIG>. The die block <NUM> has the manifold <NUM> inside to hold the active material slurry or a coating solution. A front end 25a of the manifold <NUM>, namely, an end facing the exit port has a round shape in cross section.

<FIG> shows multi lane coating, for example, three lanes coating using the shim <NUM> of <FIG> mounted in the slot die coater <NUM> of <FIG>. When the alignment between the shim <NUM> and the die blocks <NUM>, <NUM> is good and there is no deformation in the die blocks <NUM>, <NUM>, the width a of the active material layer on the current collector <NUM> is equal to the design width W of the shim <NUM> (a=W).

However, in the event of misassembly of the shim <NUM>, deformation in the die blocks <NUM>, <NUM> or a large change in properties of the active material slurry for coating, the width of the active material layer coated actually may be different from the design width W of the shim <NUM>.

<FIG> shows a change in width of the coating layer on the current collector when the conventional shim is obliquely misassembled. For example, when the shim <NUM> is obliquely misassembled as shown in <FIG>, the widths b, b', b" of the plurality of active material layers <NUM> on the current collector <NUM> are different from one another and each width b, b', b" is different from the design width W of the shim <NUM> (b<W). When the shim <NUM> is misassembled far back from the die blocks <NUM>, <NUM> as shown at the right bottom in <FIG>, the width of the active material layer <NUM> increases as it goes from b to b" (b<b'<b").

When the width mismatch is found, it is necessary to adjust the position of the shim <NUM> for the uniform width of the multi lane coating layer. However, despite the multi lane, the shim <NUM> itself is a single (integrated lane) shim, so the adjustment affects all the lanes, making it difficult to adjust only the individual lanes.

Additionally, when changing the die, it is necessary to separate and wash the shim <NUM>, and for the subsequent production, re-assembling and condition adjustment is always necessary. Since the position of the shim <NUM> is not always the same each assembly, it is necessary to adjust the condition each time the dies are disassembled and washed and then assembled again.

<CIT> discloses a coating device and a coating method for applying paint.

The present disclosure is designed to solve the above-described problem, and therefore the present disclosure is aimed at making a coating width of a multi lane model uniform and reducing a condition adjustment loss in the subsequent production.

Accordingly, the present disclosure is directed to providing a slot die coater including improved shims.

However, the technical problem to be solved by the present disclosure is not limited to the above problems, and these and other problems will be clearly understood by those skilled in the art from the following description.

To solve the above-described problem, a slot die coater of the present invention includes an upper plate; a lower plate; and a shim interposed between the upper plate and the lower plate and defining at least two individual lanes to form a slot, wherein the shim defining the individual lanes includes a fixing pin to improve positional precision when fixing to the upper plate or the lower plate and a fixing bolt for fixing to the upper plate or the lower plate.

The slot die coater further includes a manifold to hold a coating solution in the lower plate, the shim is mounted on a land portion in front of the manifold, the fixing pin may be inserted into a pin groove of the lower plate through the shim, and the fixing bolt is inserted into a fixing bolt groove of the lower plate through the shim.

The shim has a fixing bolt hole in alignment with the fixing bolt groove, and the fixing bolt hole and the fixing bolt groove have a margin in a front-rear direction (a delivery direction) and there is no margin in a left-right direction (a lengthwise direction of the slot die coater perpendicular to the delivery direction).

The upper plate may have an upper plate groove to receive a bolt head of the fixing bolt and a pin head of the fixing pin.

The upper plate groove may be a recess in the upper plate to simultaneously receive the bolt head of the fixing bolt and the pin head of the fixing pin.

A part of the shim in contact with the manifold may be rounded.

According to an example, the round processing is differently applied depending on a location at which the shim is placed on the lower plate. A side of the shim where the coating solution flows may be rounded and a part of the shim in non-contact with the coating solution may not be rounded.

A transition point from the manifold to the land portion may be a right-angle.

Further, an area at which the coating solution flows and exits between the manifold and the land portion may be rounded.

At least three lanes may be defined by the shim and there may be a difference in R value of the round processing between the lane at the center and the lane at the side.

The R value in the lane at the side may be larger than the R value in the lane at the center.

In the present disclosure, there is a height difference between a rear of the manifold and the land portion in front of the manifold by a thickness of the shim.

A lower surface of the upper plate and an upper surface of the lower plate may be coupled without a gap therebetween at the rear of the manifold, the lower surface of the upper plate and an upper surface of the shim may be coupled without a gap therebetween in front of the manifold, and the upper surface of the lower plate and a lower surface of the shim may be coupled without a gap therebetween in front of the manifold.

According to the present disclosure, the shim for multi lane configuration is not a single mass and can be individually separated. Accordingly, when the shim is mounted, only individual lanes are affected and it is possible to adjust for each individual lane.

According to the present disclosure, the shim may be mounted on the land portion in front of the manifold, and fixedly mounted on the lower plate. Since the shim is absent near the manifold, when washing, it is not necessary to separate the shim like the conventional shim. There is no need for a re-assembly process after the separation, thereby reducing the condition adjustment loss.

According to the present disclosure, the part of the shim in contact with the manifold is rounded, and the front end of the manifold at the transition from the manifold to the land portion is a right-angle, thereby preventing the generation of a turbulent flow, and achieving a smooth flow of the coating solution.

The accompanying drawings illustrate an exemplary embodiment of the present disclosure and together with the following detailed description, serve to provide a further understanding of the technical aspects of the present disclosure, and thus, the present disclosure is not construed as being limited to the drawings.

Hereinafter, an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. Prior to the description, it should be understood that the terms or words used in the specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present disclosure on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation. Therefore, the embodiments described herein and illustrations in the drawings are just an exemplary embodiment of the present disclosure and do not fully describe the technical aspects of the present disclosure, so it should be understood that a variety of other equivalents and modifications could have been made thereto at the time of filing the patent application.

Like reference numerals indicate like elements. Additionally, in the drawings, the elements are depicted in exaggerated thickness, proportion and dimension for effective description of the technical subject matter.

The slot die coater of the present disclosure is a device having a slot and used to coat a coating solution on a substrate through the slot. In the following description, 'the substrate' is a current collector and 'the coating solution' is an active material slurry. However, the scope of protection of the present disclosure is not necessarily limited thereto. For example, the substrate may be a porous support for a separator and the coating solution may be an organic matter. That is, where thin film coating is required, any type of substrate and coating solution may be used.

The slot die coater according to the present disclosure includes an upper plate, a lower plate, (at least two) shims defining individual lanes, a fixing pin and a fixing bolt. The slot die coater according to the present disclosure includes (at least two) shims defining individual lanes between an upper plate and an intermediate plate, a fixing pin and a fixing bolt, and (at least two) shims defining individual lanes between the intermediate plate and a lower plate, a fixing pin and a fixing bolt. Hereinafter, it will be described in detail with reference to the accompanying drawings.

<FIG> is an exploded cross-sectional view of the slot die coater according to an embodiment of the present disclosure, and <FIG> is an exploded cross-sectional view of a slot die coater according to another embodiment of the present disclosure. <FIG> is an enlarged view of section B in <FIG>. <FIG> is a perspective view of the shim defining individual lanes in the slot die coater according to the present disclosure.

Referring to <FIG>, the slot die coater <NUM> according to an embodiment of the present disclosure includes the upper plate <NUM>, the lower plate <NUM> and the shim <NUM> defining individual lanes.

The shim <NUM> is interposed between the upper plate <NUM> and the lower plate <NUM> to form a slot <NUM>. At least two shims <NUM> are included. When two shims <NUM> are included, a lane is defined between the two shims <NUM>. When three shims <NUM> are included, a lane is defined every two adjacent shims <NUM> and accordingly two lanes are defined. A space between the two adjacent shims <NUM> defines the slot <NUM>.

A coating solution or an active material slurry may be held in a manifold <NUM> leaves an exit port in communication with the slot <NUM> and is coated on the current collector (not shown). Although not shown in the drawing, the manifold <NUM> is connected to a coating solution supply chamber (not shown) installed outside of the manifold <NUM> with a feed pipe and is supplied with the coating solution. When the manifold <NUM> is fully filled with the coating solution, the flow of the coating solution is guided along the slot <NUM> and leaves the exit port.

The shim <NUM> is interposed between the upper plate <NUM> and the lower plate <NUM> and defines the shape of the slot <NUM>. The shim <NUM> acts as a gasket except an area in which the exit port is present to prevent leaks of the coating solution in a gap between the upper plate <NUM> and the lower plate <NUM> and is preferably made of a material having sealing characteristics.

The shim <NUM> may be fixed to the upper plate <NUM> or the lower plate <NUM>. In this embodiment, the shim <NUM> is fixed to the lower plate <NUM> for illustration purposes. The shim <NUM> includes the fixing pin <NUM> to improve the positional precision when fixing the shim <NUM> to the lower plate <NUM>. Additionally, the shim <NUM> includes the fixing bolt <NUM> for fixing the shim <NUM> to the lower plate <NUM>. After the shim <NUM> is fixed to the lower plate <NUM>, the lower plate <NUM> and the upper plate <NUM> are combined together and the bolt is installed at the rear part of the lower plate <NUM> and the upper plate <NUM> (opposite the area in which the slot <NUM> is present) to assemble the lower plate <NUM> with the upper plate <NUM>.

Most of the surfaces of the upper plate <NUM> and the lower plate <NUM> may be almost orthogonal to each other. Since the upper plate <NUM> and the lower plate <NUM> have a right angle at the edge between surfaces, there are the right-angled portions in cross section and the vertical or horizontal surface that may be used as the reference surface, so it is easy to manufacture or handle and it is possible to ensure precision. Additionally, when combining the upper plate <NUM> and the lower plate <NUM> together, facing portions may support each other with high surface contact, thereby achieving improved fixation and maintenance. In addition, when combined together, the upper plate <NUM> and the lower plate <NUM> have an approximately rectangular prism shape as a whole, and only the front side where the coating solution exits is inclined toward the substrate. The upper plate <NUM> and the lower plate <NUM> are made of, for example, a SUS material. Materials that are easy to process, such as SUS420J2, SUS630, SUS440C, SUS304 and SUS316L, may be used. The SUS is easy to process, inexpensive and highly resistant to corrosion, and can be formed in a desired shape at low cost.

By the slot die coater <NUM> having the above-described configuration, while the substrate to be coated is being moved by the rotation of a rotatable coating roll (not shown) disposed at the front side of the slot die coater <NUM>, the coating solution may be delivered and continuously coated in contact with the surface of the substrate. Alternatively, pattern coating may be intermittently formed on the substrate by supplying the coating solution and stopping the supply in an alternating manner.

Referring to <FIG>, a slot die coater <NUM> according to another embodiment of the present disclosure includes an upper plate <NUM>, a lower plate <NUM> and an intermediate plate <NUM> between them. The slot die coater <NUM> may include the shim <NUM> as described above between the upper plate <NUM> ad the intermediate plate <NUM>, and between the intermediate plate <NUM> and the lower plate <NUM>. Here, at least two shims <NUM> are included between every two die blocks. The number of shims <NUM> may change depending on the number of lanes. The manifold <NUM> may be formed in each of the intermediate plate <NUM> and the lower plate <NUM>.

Since the slot die coaters <NUM>, <NUM> are characterized by the shim <NUM> in common, the slot die coater <NUM> will be described with reference to <FIG> and <FIG>. Although the duplicate descriptions are omitted, it will be understood that the description made herein may be equally applied to the slot die coater <NUM>.

Referring to <FIG>, <FIG> and <FIG>, the slot die coater <NUM> includes the manifold <NUM> to hold the coating solution in the lower plate <NUM>. The shim <NUM> is mounted on a land portion <NUM> in front of the manifold <NUM>.

Since the shim <NUM> is only present in the land portion <NUM>, there is a difference between the height at the rear of the manifold <NUM> (opposite the exit port) and the height at the land portion <NUM> in front of the manifold <NUM> by the thickness of the shim <NUM>.

The fixing pin <NUM> may be inserted into a pin groove 110a of the lower plate <NUM> through the shim <NUM>. The fixing bolt <NUM> is inserted into a fixing bolt groove 110b of the lower plate <NUM> through the shim <NUM>.

The shim <NUM> has a pin hole 115a in alignment with the pin groove 110a. Additionally, the shim <NUM> has a fixing bolt hole 115b in alignment with the fixing bolt groove 110b.

The fixing bolt groove 110b and the fixing bolt hole 115b have a margin in the front-rear direction (delivery direction) and there is no margin in the left-right direction (lengthwise direction of the slot die coater perpendicular to the delivery direction).

Describing <FIG> and <FIG> in more detail, the fixing pin <NUM> is configured to improve the positional precision of the shim <NUM>. The fixing pin <NUM> passes through the shim <NUM> via the pin hole 115a and is inserted into the pin groove 110a, and after inserted, keeps the shim <NUM> in place. The lower plate <NUM> and the shim <NUM> may be accurately aligned through the fixing pin <NUM>. For example, after the fixing pin <NUM> is inserted to keep the shim <NUM> in place, the fixing bolt <NUM> may be installed. When installing the fixing bolt <NUM>, the fixing pin <NUM> sets its position to prevent the shim <NUM> from moving.

The fixing bolt <NUM> is used to fix the shim <NUM> to the lower plate <NUM>. The fixing bolt <NUM> passes through the shim <NUM> via the fixing bolt hole 115b and is inserted into the fixing bolt groove 110b. Since the fixing bolt hole 115b and the fixing bolt groove 110b have the margin in the front-rear direction (delivery direction), it is easy to fasten and assemble. Additionally, the absence of the margin in the left-right direction (lengthwise direction of the slot die coater perpendicular to the delivery direction) limits the horizontal movement, thereby fixing the horizontal position.

In this embodiment, the pin hole 115a through which the fixing pin <NUM> passes and the fixing bolt hole 115b through which the fixing bolt <NUM> passes are aligned in a straight line along the front-rear direction (delivery direction). At least one fixing pin <NUM> and at least one fixing bolt <NUM> may be included every shim <NUM>. Those skilled in the art will understand that an optimal number and/or various configurations of the fixing pins <NUM> and the fixing bolts <NUM> may be used within the scope of the present disclosure.

The fixing pin <NUM> and the fixing bolt <NUM> are inserted and received in the pin groove 110a and the fixing bolt groove 110b through the shim <NUM> respectively, and the lower surface of the shim <NUM> is in contact with the upper surface of the lower plate <NUM> in the land portion <NUM>. The upper surface of the lower plate <NUM> and the lower surface of the shim <NUM> may be coupled without a gap between them. Additionally, the lower surface of the upper plate <NUM> and the upper surface of the lower plate <NUM> may be coupled without a gap between them at the rear of the manifold <NUM>.

To receive the bolt head of the fixing bolt <NUM> and the pin head of the fixing pin <NUM>, the upper plate <NUM> may have an upper plate groove 105a. The upper plate groove 105a may be present at a corresponding location to receive the bolt head of the fixing bolt <NUM> and the pin head of the fixing pin <NUM>, but may be a recess in the upper plate <NUM> to simultaneously receive the bolt head of the fixing bolt <NUM> and the pin head of the fixing pin <NUM>. When the upper plate groove 105a is configured to accommodate each of the bolt head of the fixing bolt <NUM> and the pin head of the fixing pin <NUM>, positioning the upper plate <NUM> and the lower plate <NUM> in place for alignment may be a tedious operation. When the upper plate groove 105a is configured to simultaneously accommodate the bolt head of the fixing bolt <NUM> and the pin head of the fixing pin <NUM>, the bolt head of the fixing bolt <NUM> and the pin head of the fixing pin <NUM> are received in the upper plate groove 105a with a relatively sufficient clearance, leading to an increase in margin in the position alignment of the upper plate <NUM> and the lower plate <NUM>. The sufficient alignment margin makes it possible to perform the assembly related subsequent operation such as bolting to assemble the upper plate <NUM> and the lower plate <NUM> more smoothly.

Additionally, when the shim <NUM> is fixed to the lower plate <NUM> as in this embodiment, the fixing bolt <NUM> and the fixing pin <NUM> for fixing do not pass through the upper plate <NUM>. The fixing bolt <NUM> and the fixing pin <NUM> are not exposed through the die block. Additionally, the fixing bolt <NUM> is not installed in the upper plate <NUM> and is only installed in the lower plate <NUM>. As described above, the fixing bolt <NUM> and the fixing pin <NUM> are only assembled/installed in the lower plate <NUM>, and are not assembled/installed in the upper plate <NUM>. Accordingly, to check the condition of the shim <NUM> or wash the die block, it is only necessary to disassemble the lower plate <NUM> and the upper plate <NUM>, thereby improving convenience and there is no need to disassemble and re-assemble the whole slot die coater, resulting in easy process management.

When the upper plate groove 105a is formed, the bolt head of the fixing bolt <NUM> and the pin head of the fixing pin <NUM> are received in the upper plate groove 105a and the lower surface of the upper plate <NUM> and the upper surface of the shim <NUM> are in contact with each other near the upper plate groove 105a. Accordingly, the lower surface of the upper plate <NUM> and the upper surface of the shim <NUM> may be coupled without a gap between them. A gap corresponding to the thickness of the shim <NUM> is formed between the upper plate <NUM> and the lower plate <NUM> in front of the manifold <NUM> and the gap becomes the slot <NUM>.

<FIG> shows the shims <NUM> arranged at a predetermined interval on the lower plate <NUM> in the slot die coater <NUM> according to the present disclosure. For example, three lanes are defined by four shims <NUM>.

According to the present disclosure, since the shim <NUM> can be individually separated, when mounted, only individual lanes are affected and it is possible to adjust for each individual lane. The shim <NUM> may be only mounted on the land portion <NUM> in front of the manifold <NUM>, and may be fixedly mounted on the lower plate <NUM>. Since the shim <NUM> is absent near the manifold <NUM>, there is no need to separate from the die blocks to wash as opposed to the conventional shim <NUM> (see <FIG>). There is no need to re-assemble after the separation, thereby reducing the condition adjustment loss.

As shown in <FIG> and <FIG>, the shim <NUM> of the present disclosure preferably has a rounded part 115c in contact with the manifold <NUM> to achieve a smooth flow of the coating solution or a fluid, thereby preventing the generation of a turbulent flow.

As described with reference to <FIG>, the conventional slot die coater has the rounded front end 25a of the manifold corresponding to the transition point from the manifold <NUM> to the land portion. However, the present disclosure has the right-angled front end 125a of the manifold corresponding to the transition point from the manifold <NUM> to the land portion <NUM> (in cross section) as shown in <FIG>. In case that the front end 125a of the manifold corresponding to the transition point from the manifold <NUM> to the land portion <NUM> is rounded like the conventional art, it results in low fluid flow.

In the present disclosure, the part 115c of the shim <NUM> in contact with the manifold <NUM> is rounded, and the front end 125a of the manifold corresponding to the transition point from the manifold <NUM> to the land portion <NUM> is right-angled, thereby achieving a smooth flow of the fluid.

Meanwhile, in another embodiment, referring further to <FIG>, only areas 126a, 126b corresponding to a location at which the coating solution or the active material slurry flows and exits between the manifold <NUM> and the land portion <NUM> may be rounded. As described previously, the front end 125a of the manifold is a right-angle.

In particular, in the multi lane coating, there may be a difference in R value of round processing between the center and the side as shown in <FIG> shows the cross section of the manifold of the slot die coater according to another embodiment of the present disclosure. In <FIG>, (a) is a cross-sectional view of <FIG>, taken along the line I-I' and (b) is a cross-sectional view of <FIG>, taken along the line II-II'. Assume that three lanes are defined by the shim <NUM> as shown in <FIG>.

Referring to (a) of <FIG>, the lane at the center, i.e., the area 126a at the center between the manifold <NUM> and the land portion <NUM> where the coating solution or the active material slurry flows and exits has a smaller R value. Referring to (b) of <FIG>, the lane at the side, i.e., the area 126b at the side between the manifold <NUM> and the land portion <NUM> where the coating solution or the active material slurry flows and exits has a larger R value. Accordingly, it is possible to reduce a difference in flow rate between the center and the side.

Meanwhile, <FIG> shows that two sides of the part 115c of the shim <NUM> in contact with the manifold <NUM> are rounded, but the round processing may be differently applied depending on the location at which the shim <NUM> is placed on the lower plate <NUM>. <FIG> shows the rounded part of the shim in contact with the manifold in the slot die coater according to the present disclosure.

Referring to <FIG>, the shim <NUM> at the outermost edge, i.e., the side may be rounded at only one side corresponding to the inner side in which the coating solution or the active material slurry flows. The outer side in non-contact with the coating solution may not be rounded. The shim <NUM> at the center may be rounded at the two sides where the coating solution flows. Accordingly, it is possible to further reduce the turbulent flow risk in the corresponding area.

For example, the positive electrode active material slurry may be coated using the slot die coater <NUM> of the present disclosure to manufacture positive electrodes of secondary batteries. The positive electrode includes a current collector and a positive electrode active material layer on the surface of the current collector. The current collector may include electrically conductive materials, for example, Al and Cu, and a suitable one may be used according to the polarity of the current collector electrode known in the field of secondary batteries. The positive electrode active material layer may further include at least one of a plurality of positive electrode active material particles, a conductive material or a binder. Additionally, the positive electrode may further include various types of additives to supplement or improve the electrical and chemical properties.

The active material is not limited to a particular type and may include any type of active material that can be used for positive electrode active materials of lithium ion secondary batteries. Its non-limiting example may include at least one of layered compounds or compounds with one or more transition metal substitution such as lithium manganese composite oxide (LiMn<NUM>O<NUM>, LiMnO<NUM>), lithium cobalt oxide (LiCoO<NUM>), lithium nickel oxide (LiNiO<NUM>); lithium manganese oxide of formula Li<NUM>+xMn<NUM>-xO<NUM> (x is <NUM> ~ <NUM>), LiMnO<NUM>, LiMn<NUM>O<NUM>, LiMnO<NUM>; lithium copper oxide (Li<NUM>CuO<NUM>); vanadium oxide, for example, LiV<NUM>O<NUM>, LiV<NUM>O<NUM>, V<NUM>O<NUM>, Cu<NUM>V<NUM>O<NUM>; Ni site lithium nickel oxide represented by formula LiNi<NUM>-xMxO<NUM> (M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, x = <NUM> ~ <NUM>); lithium manganese composite oxide represented by formula LiMn<NUM>-xMxO<NUM> (M = Co, Ni, Fe, Cr, Zn or Ta, x = <NUM> ~ <NUM>) or Li<NUM>Mn<NUM>MO<NUM> (M = Fe, Co, Ni, Cu or Zn); LiMn<NUM>O<NUM> with partial substitution of alkali earth metal ion for Li in the formula; disulfide compounds; or Fe<NUM>(MoO<NUM>)<NUM>. In the present disclosure, the positive electrode may include a solid electrolyte material, for example, at least one of a polymer based solid electrolyte, an oxide based solid electrolyte or a sulfide based solid electrolyte.

The conductive material may be typically added in an amount of <NUM> wt% to <NUM> wt% based on the total weight of the mixture including the active material. The conductive material is not limited to a particular type, and may include any material having conductive properties without causing any chemical change to the corresponding battery, for example, at least one selected from graphite, for example, natural graphite or artificial graphite; carbon black, for example, carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black; conductive fibers, for example, carbon fibers or metal fibers; metal powder, for example, carbon fluoride, aluminum and nickel powder; conductive whiskers, for example, zinc oxide and potassium titanate; conductive metal oxide, for example, titanium oxide; and conductive materials, for example, polyphenylene derivatives.

The binder is not limited to a particular type and may include any material which assists in binding the active material and the conductive material together and binding to the current collector, for example, polyvinylidene fluoride polyvinylalcohol, carboxymethylcellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylenepropylene-diene monomer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluoro rubber and a variety of copolymers thereof. The binder may be typically included in the range of <NUM> wt% to <NUM> wt% or <NUM> wt% to <NUM> wt% based on <NUM> wt% of the electrode layer.

The negative electrode active material slurry may be coated using the slot die coater <NUM> of the present disclosure to manufacture negative electrodes of secondary batteries. The negative electrode includes a current collector and a negative electrode active material layer on the surface of the current collector. The negative electrode active material layer may further at least one of a plurality of negative electrode active material particles, a conductive material or a binder. Additionally, the negative electrode may further include a variety of additives to supplement or improve the electrical and chemical properties.

The negative electrode active material may include carbon materials, for example, graphite, amorphous carbon, diamond-like carbon, fullerene, carbon nanotubes and carbon nanohorns, lithium metal materials, alloy based materials, for example, silicon or tin alloy based materials, oxide based materials, for example, Nb<NUM>O<NUM>, Li<NUM>Ti<NUM>O<NUM>, TiO<NUM>, or a composite thereof. For the details of the conductive material, the binder and the current collector of the negative electrode, reference may be made to the description of the positive electrode.

The active material slurry including the positive electrode active material or the negative electrode active material has very high viscosity. For example, the viscosity may be <NUM> cps (centipoise, <NUM> cps = <NUM> mPa·s) or more. The viscosity of the active material slurry used to form electrodes of secondary batteries may be <NUM> cps to <NUM> cps. For example, the viscosity of the negative electrode active material slurry may be <NUM> cps to <NUM> cps. The viscosity of the positive electrode active material slurry may be <NUM> cps to <NUM> cps. Since it is necessary to coat the coating solution having the viscosity of <NUM> cps or more, the slot die coater <NUM> of the present disclosure is different in structure from devices for coating any other coating solution having lower viscosity, for example, an ordinary resin solution such as a photosensitive emulsion, a magnetic solution, an antireflection or antiglare solution, a solution for enlarging the field of view and a pigment solution for a color filter and cannot be arrived at by design modification. Since the slot die coater <NUM> of the present disclosure are, for example, designed to coat the active material slurry comprising the active material having the average particle size of about <NUM> µm, its structure is different from those of devices for coating any other coating solution including no particles having the above-described particle size, and cannot be arrived at by design modification. The slot die coater <NUM> of the present disclosure is the optimal coater for the manufacture of electrodes.

While the foregoing description has been made based on the slot die coater <NUM>, the configuration related to the shim <NUM> may be equally applied to the slot die coater <NUM>. Referring back to <FIG>, the description related to the upper plate <NUM> and the lower plate <NUM> of the slot die coater <NUM> and the shim <NUM> between them is equally applied to the upper plate <NUM> and the intermediate plate <NUM> of the slot die coater <NUM> and the shim <NUM> between them. For example, the pin groove 110a and the fixing bolt groove 110b of the lower plate <NUM> are formed in the intermediate plate <NUM>. Additionally, the description related to the upper plate <NUM> and the lower plate <NUM> of the slot die coater <NUM> and the shim <NUM> between them is equally applied to the intermediate plate <NUM> and the lower plate <NUM> of the slot die coater <NUM> and the shim <NUM> between them. The shim <NUM> between the upper plate <NUM> and the intermediate plate <NUM> and the shim <NUM> between the intermediate plate <NUM> and the lower plate <NUM> may be disposed at vertically aligned locations.

Meanwhile, the slot die coaters <NUM>, <NUM> are installed such that the delivery direction of the coating solution or the electrode active material slurry is almost horizontal (almost ± <NUM>°). However, the present disclosure is not limited to the exemplary configuration, and for example, may have vertical die configuration to deliver the electrode active material slurry from bottom to top, i.e., in the opposite direction of gravity.

While the present disclosure has been hereinabove described with respect to a limited number of embodiments and drawings, the present disclosure is not limited thereto, and it will be apparent to those skilled in the art that a variety of changes and modifications may be made thereto within the scope of the appended claims.

Claim 1:
A slot die coater (<NUM>, <NUM>), comprising:
an upper plate (<NUM>, <NUM>);
a lower plate (<NUM>, <NUM>); and
at least two individual lane shims (<NUM>) interposed between the upper plate (<NUM>, <NUM>) and the lower plate (<NUM>, <NUM>) to form a slot (<NUM>),
wherein the shim (<NUM>) includes a fixing pin (<NUM>) to improve positional precision when fixing to the upper plate (<NUM>, <NUM>) or the lower plate (<NUM>, <NUM>) and a fixing bolt (<NUM>) for fixing to the upper plate (<NUM>, <NUM>) or the lower plate (<NUM>, <NUM>),
wherein the slot die coater (<NUM>, <NUM>) further comprises a manifold (<NUM>) to hold a coating solution in the lower plate (<NUM>, <NUM>),
wherein the shim (<NUM>) is mounted on a land portion (<NUM>) in front of the manifold (<NUM>),
wherein the fixing bolt (<NUM>) is inserted into a fixing bolt groove (110b) of the lower plate (<NUM>, <NUM>) through the shim (<NUM>), and
wherein the shim (<NUM>) has a fixing bolt hole (115b) in alignment with the fixing bolt groove (110b), and the fixing bolt hole (115b) and the fixing bolt groove (110b) have a margin in a front-rear direction, which is a delivery direction, and there is no margin in a left-right direction, which is a lengthwise direction of the slot die coater (<NUM>, <NUM>) perpendicular to the delivery direction.