Die coater for coating active material on secondary battery current collectors

Abstract

The disclosed invention relates to a die coater that can effectively coat two different types of liquids simultaneously onto a current collector for a secondary battery, and includes an upper block having a second liquid inlet, a lower block connected to the upper block and having a manifold that contains a first liquid, and a coater shim interposed between the upper block and the lower block and forming a first slit and a second slit that are separated from each other, wherein the coater shim includes a first coater shim that forms the first slit that discharges the first liquid contained in the manifold, and a second coater shim that forms the second slit that discharges the second liquid supplied through the second liquid inlet, and the first coater shim and second coater shim have the same height, are not stacked vertically, and are placed on the same plane between the upper block and the lower block.

Description

[Technical field]

[0001] The present invention relates to a die coater that can effectively coat two different types of liquids simultaneously onto a current collector for a secondary battery.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0004219 dated January 11, 2022, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] The demand for secondary batteries is also increasing rapidly due to technological development and increasing demand for mobile devices. Among them, lithium secondary batteries are widely used as an energy source for various electronic products as well as various mobile devices due to their high energy density, operating voltage, and excellent storage and life characteristics.

[0004] Lithium secondary batteries use electrodes in which an active material layer and an insulating layer are formed on the surface of a current collector. Such electrodes are manufactured by applying both an electrode slurry containing an active material and an insulating coating liquid containing an insulating material to the surface of a current collector using a coating device such as a die coater so that the edges of the electrode mixture layer partially overlap, and then drying the applied liquid.

[0005] 1 illustrates a conventional die coater 1 for applying an electrode slurry. The die coater 1 includes an upper block 2 and a lower block 3, with a die coater shim 4 interposed between the upper block 2 and the lower block 3, and the upper block 2 and the lower block 3 fastened to each other by a plurality of bolt members. The lower block 3 is provided with a manifold 5 that contains a certain volume of electrode slurry, and the manifold 5 communicates with an external electrode slurry supply unit (not shown).

[0006] Here, the die coater shim serves to form a slit of a suitable height between the upper block and the lower block, while at the same time restricting the flow direction of the electrode slurry so that the electrode slurry is discharged toward the slit and also serves to seal so that the electrode slurry does not leak to other parts other than the slit. The die coater shim has guides protruding from both ends in the width direction, and the distance between these guides determines the width over which the electrode slurry is applied onto the current collector.

[0007] The insulating coating liquid is applied to both edges in the width direction of the electrode slurry applied to the current collector, and generally, after the electrode slurry is applied to the current collector, the insulating coating liquid is applied in an additional process using a separate device. However, applying the electrode slurry and the insulating coating liquid to the current collector in separate processes is not preferable in terms of production efficiency.

[0008] To overcome these limitations, a technology was introduced in which independent slits are formed in a single die coater shim to eject the electrode slurry and insulating coating liquid, respectively. However, this causes problems such as poor quality of the current collector when one of the liquids leaks inside the die coater and the two types of liquid (e.g. electrode slurry and insulating coating liquid) are mixed, or the two solutions are mixed and ejected at the exit of the slit. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Korean Patent Publication No. 10-2021-0083512 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a die coater capable of effectively and simultaneously coating two different types of liquid onto a current collector for a secondary battery.

[0011] However, the technical problem that the present invention aims to solve is not limited to the above-mentioned problem, and other problems not mentioned will be clearly understood by those of ordinary skill in the art from the description of the invention described below. [Means for solving the problem]

[0012] The present invention relates to a die coater that can effectively coat two different types of liquids simultaneously on a current collector for a secondary battery, and includes an upper block having a second liquid inlet, a lower block connected to the upper block and having a manifold that contains a first liquid, and a coater shim interposed between the upper block and the lower block and forming a first slit and a second slit that are separated from each other. In one example, the coater shim includes a first coater shim that forms the first slit that discharges the first liquid contained in the manifold, and a second coater shim that forms the second slit that discharges the second liquid supplied through the second liquid inlet, and the first coater shim and the second coater shim have the same height, are not stacked vertically, and are placed on the same plane between the upper block and the lower block.

[0013] Thereby, the width of the first slit is limited by the width of the second coater shim.

[0014] The height of the first slit corresponds to the height of the first coater shim, and the height of the second slit is smaller than the height of the second coater shim.

[0015] In a specific example, the second coater shim has a concave flow groove that is open toward the upper block and has a bottom surface, the closed end of the flow groove is connected to a second liquid inlet of the upper block, and the open end of the flow groove forms the second slit.

[0016] The first coater shim includes a base extending along the width direction, and a first guide and a second guide protruding from both ends of the base, and one side wall of the pair of second coater shims is closely attached to the inner walls of the first guide and the second guide, respectively.

[0017] As a result, the distance between the other side walls of the pair of second coater shims corresponds to the width of the first slit.

[0018] In one embodiment, the lower block has a through-threaded hole accessible to a bottom surface of the second coater shim, and an end of a bolt screwed into the through-threaded hole may press the second coater shim to tightly contact the upper block.

[0019] In addition, an expanded pressure block hole is formed at a coupling direction end of the through screw hole, and a pressure block accommodated in the pressure block hole can be interposed between the bolt and the second coater shim to pressurize the second coater shim.

[0020] For example, the pressure block may press both side wall portions of the second coater shim.

[0021] Meanwhile, according to another embodiment of the present invention, the coating layer may include a concave U-shaped flow channel having a bottom surface and open toward the upper block, a closed end of the U-shaped flow channel being connected to a second liquid inlet of the upper block, and two open ends of the U-shaped flow channel forming a third slit. The coating layer may further include a third coater shim having the same height as the first coater shim and the second coater shim, and the third coater shim may be disposed between the first guide and the second guide.

[0022] The lower block has a through-threaded hole accessible to the bottom surface of the third coater shim, and an end of a bolt screwed into the through-threaded hole can press the third coater shim to adhere it closely to the upper block.

[0023] In addition, an expanded pressure block hole is formed at a coupling direction end of the through screw hole, and a pressure block accommodated in the pressure block hole can be interposed between the bolt and a third coater shim to pressurize the third coater shim.

[0024] For example, the pressure block may press both side wall portions of the third coater shim. Effect of the Invention

[0025] The die coater of the present invention having the above-mentioned configuration is configured to simultaneously eject two different types of liquid, for example, an electrode slurry and an insulating coating liquid, and in particular, the first slit and the second slit which eject the first liquid and the second liquid, respectively, are physically separated from each other in the die coater.

[0026] Furthermore, the second coater shim forming the second slit maintains airtightness by a separate pressurizing structure, thereby making it possible to reliably prevent internal mixing of the first liquid and the second liquid.

[0027] As a result, the die coater of the present invention makes it possible to effectively coat two different types of liquids simultaneously onto a current collector.

[0028] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following detailed description.

[0029] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. [Brief description of the drawings]

[0030] [Figure 1] 1 is a diagram illustrating the configuration of a die coater according to the prior art. [Diagram 2] FIG. 2 is an exploded perspective view illustrating a die coater according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a plan view of the die coater seen through the upper block. [Figure 4] FIG. 4 is an enlarged front view of part “A” in FIG. [Diagram 5] 1 is a diagram illustrating a pressing structure of a die coater according to an embodiment of the present invention. [Figure 6] FIG. 2 is an exploded perspective view illustrating a die coater according to another embodiment of the present invention. [Figure 7] FIG. 7 is a perspective view of a third coater shim included in the die coater of FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be described in detail below.

[0032] However, this is not intended to limit the invention to the particular embodiments, but should be understood to include all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

[0033] In the present invention, the terms "comprise" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but should be understood as not precluding the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0034] In addition, in the present invention, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion in between. Conversely, when a layer, film, region, plate, or other portion is described as being "under" the other portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion in between. In addition, in the present application, being "on" can include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0035] The present invention relates to a die coater that can effectively coat two different types of liquids simultaneously onto a current collector for a secondary battery.

[0036] In one example, the die coater of the present invention includes an upper block having a second liquid inlet, a lower block connected to the upper block and having a manifold that contains a first liquid, and a coater shim interposed between the upper block and the lower block and forming a first slit and a second slit that are separated from each other.

[0037] Here, the die coater of the present invention includes two types of coater shims, a first coater shim and a second coater shim. The first coater shim forms a first slit for discharging a first liquid contained in a manifold in the lower block, and the second coater shim forms a second slit for discharging a second liquid supplied through a second liquid inlet in the upper block. In particular, the first coater shim and the second coater shim have the same height and are not stacked vertically, so that the first coater shim and the second coater shim are placed on the same plane between the upper block and the lower block.

[0038] The die coater of the present invention is configured to simultaneously eject two different types of liquid, for example, an electrode slurry and an insulating coating liquid. In particular, the first slit and the second slit that eject the first liquid and the second liquid, respectively, are physically separated from each other in the die coater, thereby making it possible to prevent internal mixing of the first liquid and the second liquid.

[0039] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the die coater according to the present invention will be described in detail with reference to the accompanying drawings.

[0040] (First embodiment) 2 is an exploded perspective view showing a die coater 10 according to an embodiment of the present invention. The overall configuration of the die coater 10 according to the present invention will be described with reference to FIG.

[0041] As described above, the present invention relates to a die coater 10 that can effectively coat two different types of liquids simultaneously on a current collector for a secondary battery. The two different types of liquids can be, for example, an electrode slurry and an insulating coating liquid. The following description can be understood as an embodiment in which the first liquid is an electrode slurry and the second liquid is an insulating coating liquid.

[0042] The die coater 10 of the present invention includes an upper block 100, a lower block 200, and a coater shim 300 interposed therebetween. In particular, in the present invention, the coater shim 300 includes a first coater shim 310 and a second coater shim 320.

[0043] The upper block 100 includes a second liquid inlet 120 and occupies approximately half of the body of the die coater 10. The lower block 200 is a portion that occupies the remaining half and is connected to the upper block 100, and includes a manifold 210 that contains the first liquid. Here, the upper and lower portions are defined as upper and lower portions based on the drawing, and do not limit the actual installation direction of the die coater 10.

[0044] 2, the first liquid inlet 110 communicating with the manifold 210 of the lower block 200 is shown as being formed in the upper block 100, but the first liquid inlet 110 may be formed in the lower block 200. Meanwhile, the second liquid inlet 120 must be formed in the upper block 100, but the layout design is limited by the flow channel 322 formed in the second coater shim 320, which will be described later, and its airtight structure.

[0045] The coater shim 300 is interposed between the upper block 100 and the lower block 200, and basically forms a slit of a suitable height for discharging a liquid between the upper block 100 and the lower block 200. The coater shim 300 restricts the flow direction of the liquid flowing into or contained in the die coater 10 so that the liquid is discharged toward the slit without flowing back, and also serves to seal the liquid so that it does not leak to other parts than the slit.

[0046] In the present invention, the coater shim 300 includes a first coater shim 310 and a second coater shim 320, and the first coater shim 310 and the second coater shim 320 form a first slit 318 and a second slit 328 separated from each other. Specifically, the first coater shim 310 forms the first slit 318 for discharging the first liquid contained in the manifold 210 of the lower block 200, and the second coater shim 320 forms the second slit 328 for discharging the second liquid supplied through the second liquid inlet 120 of the upper block 100.

[0047] The first coater shim 310 and the second coater shim 320 have the same height and are not stacked one on the other. Therefore, the first coater shim 310 and the second coater shim 320 are placed on the same plane between the upper block 100 and the lower block 200.

[0048] Fig. 3 is a plan view of the die coater 10 seen through the upper block 100, and Fig. 4 is an enlarged front view of part "A" in Fig. 3. Referring to Figs. 3 and 4, the first coater shim 310 includes a base 312 extending along the width direction, and a first guide 314 and a second guide 316 each protruding from both ends of the base 312. The second coater shim 320 is open toward the upper block 100 and includes a concave flow channel 322 having a bottom surface (see Fig. 5).

[0049] Here, the first coater shim 310 forms a space between the first guide 314 and the second guide 316 as a first slit 318, and the second coater shim 320 has a concave flow channel 322 having a bottom surface, the open end of which forms a second slit 328. Since the depth of the flow channel 322 is smaller than the thickness (height) of the second coater shim 320, the height of the first slit 318 corresponds to the height of the first coater shim 310, and the height of the second slit 328 is smaller than the height of the second coater shim 320, as shown in FIG.

[0050] In addition, the first coater shim 310 and the second coater shim 320 have the same height and are placed on the same plane without being stacked vertically, so that the width of the first slit 318 is limited by the width of the second coater shim 320 .

[0051] 3, one side wall 324 of a pair of second coater shims 320 is in close contact with the inner side walls of the first guide 314 and the second guide 316, respectively. As a result, the distance between the opposing other side walls 324 (the side opposite the intimately contacted side walls) of the pair of second coater shims 320 corresponds to the substantial width of the first slit 318. In other words, the width of the first slit 318 is the length obtained by subtracting the width of the second coater shim 320 from the distance between the inner side walls of the first guide 314 and the second guide 316.

[0052] Looking at the structure of the second slit 328 formed by the second coater shim 320, both side walls 324 of the second coater shim 320 separate it from the first liquid in the first slit 318, and while the lower side of the flow channel 322 is the bottom surface, the upper side is in close contact with the upper block 100, so that the second coater shim 320 is structurally completely isolated from the first liquid. Therefore, the die coater 10 according to the present invention significantly reduces the possibility of two different liquids being mixed therein.

[0053] Furthermore, the present invention can better maintain the airtightness of the second coater shim 320 by using the pressurizing structure shown in Fig. 5. The pressurizing structure of Fig. 5 is intended to reinforce the airtightness between the upper block 100 and the second coater shim 320. That is, while both sides and the bottom of the first coater shim 310 are closed structures that structurally ensure airtightness, the airtightness of the top surface is affected by the degree of contact with the upper block 100. Therefore, by applying the pressurizing structure of Fig. 5, the second coater shim 320 can be more reliably contacted with the upper block 100.

[0054] 5, the closed end of the concave flow channel 322 formed in the second coater shim 320 is connected to the second liquid inlet 120 of the upper block 100 to receive the second liquid. For reference, the number and positions of the second liquid inlet 120 correspond to the number and positions of the second coater shim 320 as shown in FIG.

[0055] In the illustrated embodiment, the installation position of the second coater shim 320 is accurately set by pin members 130 provided in the upper block 100. The pin members 130 protrude from the periphery of the second liquid inlet 120, and the pin members 130 are fitted into coupling holes 326 provided in the second coater shim 320, thereby fixing the position of the second coater shim 320.

[0056] Here, it is preferable that the pin members 130 and the coupling holes 326 are designed so that the fixed position and direction of the second coater shim 320 are uniformly determined. In particular, since the second coater shim 320 fitted with the pin members 130 does not rotate, the installation direction must be fixed, which can be achieved by designing the pin members 130 to be multiple, forming the pin members 130 and the coupling holes 326 in a shape other than a circular cross section, or combining such structures. If necessary, the lower block 200 may be provided with a concave pin insertion hole 220 for receiving the protruding pin members 130.

[0057] The lower block 200 is formed with a through-threaded hole 230 that is accessible to the bottom surface of the second coater shim 320, and the end of a bolt 232 that is screwed into the through-threaded hole 230 presses the second coater shim 320, thereby more firmly adhering the top surface of the second coater shim 320 to the upper block 100.

[0058] Furthermore, in order to more effectively bring the second coater shim 320 into close contact with the upper block 100, an expanded pressurizing block hole 240 is formed at the end of the through screw hole 230 in the coupling direction (the direction in which the bolt is tightened), and a pressurizing block 242 accommodated in the pressurizing block hole 240 is interposed between the bolt 232 and the second coater shim 320, so that the second coater shim 320 can be more effectively pressed. For example, the pressurizing block 242 presses both side walls 324 of the second coater shim 320, so that the second coater shim 320 can be more effectively pressed.

[0059] In this way, in addition to the pressure force created by the pressure structure provided separately for the second coater shim 320, in other words, the pressure force created by the mutual fastening of the upper block 100 and the lower block 200, the additional pressure force applied by the bolt 232 pressing the second coater shim 320 makes it extremely unlikely that the second liquid flowing through the second coater shim 320 will mix with the surrounding first liquid.

[0060] Second embodiment The second embodiment of the present invention is suitable for the case where a first liquid and a second liquid, for example, an electrode slurry and an insulating coating liquid, are applied in two or more rows to a current collector supplied in a coil shape, and then slitting is performed.

[0061] That is, the second embodiment corresponds to an embodiment suitable for simultaneously applying an active material coating having a structure of "insulating coating liquid-electrode slurry-insulating coating liquid" to a current collector in two or more rows.

[0062] 6 is an exploded perspective view illustrating a die coater 10 according to another embodiment of the present invention, and the illustrated second embodiment includes the structure of the first embodiment described above as is, and further includes a third coater shim 330. The third coater shim 330 is installed in the middle of the die coater 10 in the width direction, and ejects the second liquid in two streams through a U-shaped flow channel 332. That is, the third coater shim 330 is configured to eject the second liquid in two streams corresponding to each of the second coater shims 320 on both sides arranged in close contact with the first guide 314 and the second guide 316.

[0063] The third coater shim 330 is disposed between the first guide 314 and the second guide 316 of the first coater shim 310, and acts as an element restricting the first slit 318 in the same manner as the second coater shim 320 described above restricts the substantial width of the first slit 318. Therefore, the third coater shim 330 disposed in the middle of the first slit 318 splits the first liquid into two stripes, thereby discharging the first liquid in two parallel rows. The height of the third coater shim 330 corresponds to the heights of the first coater shim 310 and the second coater shim 320.

[0064] By arranging the third coater shim 330 in this manner and discharging the second liquid in two rows, a coating structure of "second liquid-first liquid-second liquid" is formed on the current collector in two parallel rows along the longitudinal direction of the current collector, and by performing a slitting process to cut the middle of the two parallel rows, two current collector rolls can be obtained.

[0065] 7 is a perspective view of the third coater shim 330, which has the same configuration as the second coater shim 320 except for the structure of the U-shaped flow channel 332. Specifically, the third coater shim 330 has a concave U-shaped flow channel 332 that is open toward the upper block 100 and has a bottom surface. A closed end of the U-shaped flow channel 332 is connected to the second liquid inlet 120 of the upper block 100, and the two open ends of the U-shaped flow channel 332 form a third slit 338. Similarly, the position of the third coater shim 330 is fixed so as not to rotate by fitting a pin member 130 into a coupling hole 336.

[0066] The third coater shim 330 may also be applied with the same pressing structure as the second coater shim 320, and its configuration and operation are the same as those described above. That is, the lower block 200 is formed with a through-threaded hole 230 that is accessible to the bottom surface of the third coater shim 330, and the end of a bolt 232 that is screwed into the through-threaded hole 230 may press the third coater shim 330 to bring it into close contact with the upper block 100.

[0067] In addition, an expanded pressure block hole 240 is formed at an end of the through screw hole 230 in the coupling direction, and a pressure block 242 accommodated in the pressure block hole 240 is interposed between the bolt 232 and the third coater shim 330 to pressurize the third coater shim 330. For example, the pressure block 242 may pressurize both side walls 334 of the third coater shim 330.

[0068] Here, the second embodiment describes adding one third coater shim 330 to simultaneously apply the first and second liquids to the electrode body in two parallel rows, but it will be obvious to a person of ordinary skill in the art that it is also possible to add two or more third coater shims 330 to apply in three or more rows.

[0069] The present invention has been described in more detail above with reference to the drawings and embodiments, etc. However, the configurations described in the drawings or embodiments, etc. in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, so it should be understood that there may be various equivalents and modifications that can replace them at the time of filing this application. [Industrial Applicability]

[0070] The die coater of the present invention is useful for effectively and simultaneously coating two different types of liquids onto a current collector for a secondary battery. [Explanation of symbols]

[0071] 10: Die coater 100: Upper block 110: 1st liquid inlet 120:Second liquid inlet 130: Pin member 200: Lower block 210: Manifold 220: Pin insertion port 230:Through-thread hole 232: Bolt 240: Pressurized block hole 242: Pressure block 300: Coater shim 310: 1st coater shim 312: Bass 314: First Guide 316: 2nd Guide 318: First slit 320: 2nd coater shim 322: Flow channel 324: Side wall 326: Bonding hole 328: Second slit 330: 3rd coater shim 332: U-shaped flow channel 334: Side wall 336: Bonding hole 338: 3rd slit

Claims

1. an upper block having a second liquid inlet; a lower block coupled to the upper block and including a manifold for receiving a first liquid; and a coater shim interposed between the upper block and the lower block and forming a first slit and a second slit separated from each other; Including, The coater shim is a first coater shim that forms the first slit for discharging a first liquid contained in the manifold, and a second coater shim that forms the second slit for discharging a second liquid supplied via the second liquid inlet, A die coater, wherein the first coater shim and the second coater shim have the same height, are not stacked one on top of the other, and are placed on the same plane between the upper block and the lower block.

2. The die coater of claim 1 , wherein the width of the first slit is limited by the width of the second coater shim.

3. the height of the first slit corresponds to the height of the first coater shim; The die coater of claim 2 , wherein a height of the second slit is less than a height of the second coater shim.

4. The second coater shim is 4. The die coater of claim 3, further comprising a concave flow channel having a bottom surface and open toward the upper block, a closed end of the flow channel being connected to the second liquid inlet of the upper block, and an open end of the flow channel forming the second slit.

5. The first coater shim is The tapered portion includes a base extending in a width direction, and a first guide and a second guide extending from both ends of the base, The die coater according to claim 4 , wherein one side wall of the pair of second coater shims is in close contact with the inner side walls of the first guide and the second guide, respectively.

6. The die coater according to claim 5 , wherein a distance between other side walls of the pair of second coater shims corresponds to a width of the first slit.

7. The lower block has a through-hole formed at the bottom surface of the second coater shim through which a bolt can be accessed.

2. The die coater of claim 1, wherein the end of the bolt that threads into the through-threaded hole presses the second coater shim against the upper block.

8. The through-thread hole is provided at its end in the coupling direction with an expanded pressure block hole. The die coater according to claim 7 , wherein the pressure block housed in the pressure block hole is interposed between the bolt and a second coater shim to press the second coater shim.

9. The die coater according to claim 8 , wherein the pressure block presses both side wall portions of the second coater shim.

10. a concave U-shaped flow channel having a bottom surface and open toward the upper block, a closed end of the U-shaped flow channel being connected to the second liquid inlet of the upper block, two open ends of the U-shaped flow channel forming a third slit, and further including a third coater shim having the same height as the first coater shim and the second coater shim, The die coater of claim 5 , wherein the third coater shim is disposed between the first guide and the second guide.

11. The lower block has a through-hole formed at the bottom surface of the third coater shim through which a bolt can be accessed.

11. The die coater of claim 10, wherein the end of the bolt that threads into the through-threaded hole presses the third coater shim against the upper block.

12. The through-thread hole is provided at its end in the coupling direction with an expanded pressure block hole. The die coater according to claim 11 , wherein the pressure block housed in the pressure block hole is interposed between the bolt and the third coater shim to press the third coater shim.

13. The die coater according to claim 12 , wherein the pressure block presses both side wall portions of the third coater shim.

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