Slot die with divided manifold

Abstract

The disclosed slot die comprises: a first body with a plurality of manifolds that are divided to independently isolate and accommodate electrode slurry; a second body pressed and fastened to the first body so as to maintain the airtightness of the plurality of manifolds; and a coater shim closely interposed between the first body and the second body so as to form a plurality of slits communicating with the plurality of manifolds between coupling surfaces of the first body and the second body.

Description

Slot die with split manifold

[0001] The present invention relates to a slot die for applying an active material on a current collector for a secondary battery.

[0002] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2023-0113882, filed August 29, 2023, the entire contents of which are incorporated herein by reference.

[0003] With technological advancements and growing demand for mobile devices, demand for secondary batteries is also rapidly increasing. Among these, lithium secondary batteries are widely used as a power source for various mobile devices and other electronic products due to their high energy density, high operating voltage, and excellent storage and lifespan characteristics.

[0004] Lithium secondary batteries utilize electrodes formed with active material layers and insulating layers on the surface of a current collector. These electrodes are manufactured by applying an electrode slurry containing an active material, etc., and an insulating coating solution containing an insulating material, etc., to the surface of the current collector using a coating device such as a slot die, and then drying them.

[0005] Fig. 1 illustrates a conventional slot die (1) for applying electrode slurry. The slot die (1) includes an upper block (2) and a lower block (3), and a coater core (4) is interposed between the upper block (2) and the lower block (3), which are fastened together by a plurality of bolt members. The lower block (3) is provided with a manifold (5) having a concave space for receiving electrode slurry, and the manifold (5) is connected to an external electrode slurry supply unit (not shown) via a pipe.

[0006] The slot die (1) exemplarily illustrated in Fig. 1 is a single-lane type in which electrode slurry is discharged in a single line. In contrast, Fig. 2 exemplarily illustrates a multi-lane type slot die (1') in which electrode slurry is discharged in multiple rows. The coater core (4') provided in the slot die (1') of Fig. 2 has a plurality of branches (6) extending across the manifold (5) as well as on both sides of the manifold (5). Accordingly, a plurality of lanes are formed between the branches (6) protruding from the tip of the manifold (5).

[0007] However, in a multi-lane type slot die such as that in Fig. 2, there is a problem in that it is difficult to maintain a uniform amount of electrode slurry that is discharged separately between lanes. This is due to the flow pressure of the electrode slurry acting on each lane, warping or twisting of the slot die due to its large size, and the installation deviation of the coater core that varies depending on the operator. In this way, if there is a deviation in the amount of electrode slurry discharged for each lane, this causes the coating loading amount and coating width of the current collector to become locally uneven, which ultimately has a negative impact on the quality of the secondary battery.

[0008] The purpose of the present invention is to enable uniform formation of a local coating amount and coating width across all lanes of a slot die.

[0009] In addition, another purpose of the present invention is to solve the problem of variation in the installation of the coater core for each worker.

[0010] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0011] The present invention relates to a slot die, and in one example, includes a first body having a plurality of manifolds that are divided to independently and isolately receive electrode slurry, a second body press-fastened to the first body so as to maintain the sealing of the plurality of manifolds, and a coater shim that is tightly interposed between the first body and the second body so as to form a plurality of slits communicating with the plurality of manifolds between the mating surfaces of the first body and the second body.

[0012] The slot die of the present invention has a plurality of slits assigned to each manifold so as to communicate with any one of the plurality of manifolds.

[0013] In one embodiment of the present invention, the cotter core may include a base core that seals the rear end and both side surfaces of the plurality of manifolds, and a plurality of spacer cores that are spaced apart from each other to form the plurality of slits at the front ends of the plurality of manifolds.

[0014] Here, some of the plurality of spacer cores may be arranged corresponding to at least one bulkhead that isolates the plurality of manifolds from each other.

[0015] The slot die of the present invention includes a slurry pipe for supplying slurry to the plurality of manifolds, and the slurry pipe includes a main pipe formed as a single pipe, a buffer pipe for receiving a certain volume of electrode slurry supplied from the main pipe, a plurality of branch pipes branched and connected from the buffer pipe to correspond to the number of the plurality of manifolds, and a plurality of flow control valves provided for each of the branch pipes.

[0016] The above plurality of flow control valves are independently controlled in their opening amounts for corresponding manifolds so as to reduce the deviation in slurry loading along the width direction of the electrodes in which the plurality of slits are arranged in a row.

[0017] In one embodiment of the present invention, the plurality of flow control valves can have their respective opening amounts independently controlled so that the slurry flow rate is symmetrical with respect to the centers of the plurality of slits arranged in a row for the plurality of manifolds.

[0018] In addition, the plurality of flow control valves can be controlled to have the largest or smallest opening amount for a manifold located in the middle of the plurality of manifolds.

[0019] In addition, the first body may be provided with a plurality of fixing pins at the mounting positions of the spacer core, and a plurality of holes into which the fixing pins are inserted may be formed in the spacer core.

[0020] In addition, the spacer core may be provided with an insulating solution supply hole through which insulating solution is supplied, and a groove extending to the tip of the spacer core and connected to the insulating solution supply hole.

[0021] The slot die of the present invention having the above configuration comprises a plurality of manifolds connected to a plurality of slits, and thus can control differently the flow rate of electrode slurry supplied to each manifold. Since the discharge amount of electrode slurry can be independently controlled for each group of slits assigned to each manifold, it is possible to adjust the coating loading amount and the coating width deviation that occur along the width direction of the current collector, thereby improving the quality of the secondary battery.

[0022] In addition, the slot die of the present invention is provided with a plurality of fixing pins on the first body in accordance with the mounting position of the spacer core, and a plurality of holes formed in the spacer core into which the fixing pins are inserted. By means of the configuration of the pins and holes, the spacer core can always be installed consistently without being influenced by the operator, thereby resolving the problem of coating loading and coating width deviation due to spacer core installation deviation.

[0023] However, the technical effects that can be obtained through the present invention are not limited to the above-described effects, and other effects that are not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0024] 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 idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0025] Figures 1 and 2 are drawings showing an example of a slot die according to the prior art.

[0026] FIG. 3 is an exploded view of the first body and the second body of a slot die according to one embodiment of the present invention.

[0027] Fig. 4 is a plan view showing a structure in which a cotter core is mounted on the first body.

[0028] FIG. 5 is a drawing illustrating one embodiment of a slot die including a slurry pipe.

[0029] Figure 6 is a drawing illustrating an example of a slurry loading profile according to the opening amount of each flow control valve for three manifolds.

[0030] Fig. 7 is a drawing showing one embodiment of a structure for mounting a spacer core on a first body.

[0031] The present invention can be modified in various ways and has many embodiments, and specific embodiments will be described in detail below.

[0032] However, this is not intended to limit the present invention to a specific embodiment, but should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

[0033] In the present invention, it should be understood that terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0034] Additionally, in the present invention, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only cases where it is "directly above" the other part, but also cases where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "under" another part, this includes not only cases where it is "directly below" the other part, but also cases where there is another part in between. Furthermore, in the present application, "being placed on" may include cases where it is placed below as well as above.

[0035]

[0036] The present invention relates to a slot die, and in one example, includes a first body having a plurality of manifolds that are divided to independently and isolately receive electrode slurry, a second body press-fastened to the first body so as to maintain the sealing of the plurality of manifolds, and a coater shim that is tightly interposed between the first body and the second body so as to form a plurality of slits communicating with the plurality of manifolds between the mating surfaces of the first body and the second body.

[0037] In this way, the slot die of the present invention is provided with a plurality of manifolds connected to a plurality of slits, and thus the flow rate of electrode slurry supplied to each manifold can be controlled differently. Since the discharge amount of electrode slurry can be independently controlled for each slit group assigned to each manifold, it is possible to adjust the coating loading amount and the coating width deviation that occur along the width direction of the current collector, thereby improving the quality of the secondary battery.

[0038] Hereinafter, a specific embodiment of a slot die (10) according to the present invention will be described in detail with reference to the attached drawings. For reference, the directions of front / back, up / down / left / right, etc., used to designate relative positions in the following description are intended to aid understanding of the invention, and unless otherwise specifically defined, the directions depicted in the drawings are taken as a reference.

[0039]

[0040] [First Embodiment]

[0041] FIG. 3 is an exploded view of a first body (100) and a second body (200) of a slot die (10) according to one embodiment of the present invention. Referring to FIG. 3, the slot die (10) of the present invention includes a first body (100) and a second body (200) that are mutually fastened, and a coater shim (300) interposed between the first body (100) and the second body (200).

[0042] The first body (100) is provided with a manifold (110) that receives electrode slurry supplied from the outside as a lower block of the slot die (10). In particular, in the slot die (10) of the present invention, the manifold (110) provided in the first body (100) is composed of a plurality of manifolds (110) divided by partition walls (112), and each manifold (110) independently receives electrode slurry. That is, the electrode slurry received in each manifold (110) cannot move to another adjacent manifold (110).

[0043] The second body (200) is an upper block of the slot die (10) and is pressurized and fastened to the first body (100) so that the sealing of the plurality of manifolds (110) provided in the first body (100) is maintained. For example, the first and second bodies (100, 200) can be firmly coupled to each other by a plurality of bolts (210) that penetrate the second body (200) and are screw-fastened to the first body (100).

[0044] The coater core (300) is tightly interposed between the first body (100) and the second body (200) to form a plurality of slits (350) at the tip of the slot die (10) (here, the tip refers to the end from which the electrode slurry is discharged). The coater core (300) that is tightly interposed between the joining surfaces of the first and second bodies (100, 200) that are pressurized and fastened has a predetermined thickness, and the coater core (300) that is dividedly arranged at the tip of the slot die (10) forms a plurality of slits (350). Each slit (350) forms one lane through which the electrode slurry is discharged in a row on the surface of the current collector.

[0045] In the illustrated embodiment, the first body (100) is provided with three manifolds (110), and the coater shim (300) is composed of one base shim (310) and a plurality of spacer shims (320). The base shim (310) seals the rear end and both side surfaces of the plurality of manifolds (110), and the plurality of spacer shims (320) are spaced apart from each other at the front ends of the plurality of manifolds (110) to form a plurality of slits (350). According to this embodiment, the base shim (310) only serves to seal the rear end and both side surfaces of the manifold (110), and in fact, only the spacer shims (320) are involved in forming the slits (350). Accordingly, according to an embodiment in which the coater core (300) is divided into a base core (310) and a plurality of spacer cores (320), only the spacer core (320) having a problem in slurry loading control can be replaced or adjusted, thereby enabling local loading control and reducing the cost, time, etc. associated with changing the coater core (300).

[0046] Fig. 4 is a plan view illustrating a structure in which a cotter shim (300) is mounted on a first body (100). Fig. 4 clearly illustrates the relationship between the manifold (110) and the cotter shim (300), particularly the arrangement relationship between a plurality of manifolds (110) and a plurality of spacer shims (320). As illustrated, a plurality of slits (350) are assigned to each manifold (110) so as to communicate with any one of the plurality of manifolds (110). In other words, at least one slit (350) is connected to each manifold (110). One slit (350) is connected to only one manifold (110), and a plurality of slits (350) may be connected to one manifold (110) as illustrated.

[0047] If a plurality of slits (350) sharing a single manifold (110) are referred to as a group of slits (350), the illustrated embodiment has three manifolds (110), and thus the plurality of slits (350) are distinguished into three groups of slits (350). Since the plurality of manifolds (110) are completely separated from each other, it is possible to differently control the flow rate of the electrode slurry supplied to each manifold (110), and as a result, the discharge amount of the electrode slurry can be independently controlled for each group of slits (350) assigned to each manifold (110). By controlling the discharge amount of the slurry for each group of slits (350), it is possible to adjust the coating loading amount and the coating width deviation that occur along the width direction of the current collector, thereby improving the quality of the secondary battery.

[0048] Here, in order to ensure that one slit (350) is connected to only one manifold (110), it is necessary to consider a partition wall (112) that divides the plurality of manifolds (110). That is, some of the plurality of spacer shims (320) need to be arranged corresponding to at least one partition wall (112) that isolates the plurality of manifolds (110) from each other. The width of the spacer shim (320) is designed to be at least as large as the thickness of the partition wall (112). Accordingly, when one end of the spacer shim (320) is mounted so as to face the partition wall (112), both sides of the spacer shim (320) come into contact with different manifolds (110), and as a result, the two slits (350) located on both sides of the spacer shim (320) are connected to different manifolds (110).

[0049] FIG. 5 is a drawing illustrating one embodiment of a slot die (10) including a slurry pipe (400). The slurry pipe (400) is a pipe that supplies slurry to a plurality of manifolds (110), and in the illustrated embodiment, the slurry pipe (400) includes a main pipe (410), a buffer pipe (420), a plurality of branch pipes (430), and a plurality of flow control valves (440).

[0050] The main pipe (410) may be formed as a single pipe, and electrode slurry is supplied from the outside through the main pipe (410). In addition, a buffer pipe (420) is connected to the outlet of the main pipe (410). The buffer pipe (420) serves to receive a certain volume of electrode slurry supplied from the main pipe (410), and the fluctuation range and intensity of the slurry flow occurring in the slot die (10) are buffered by the buffer pipe (420). In addition, a plurality of branch pipes (430) are connected to the buffer pipe (420), each of which is assigned to a plurality of manifolds (110), and a flow control valve (440) is installed in each branch pipe (430). That is, a branch pipe (430) and a flow control valve (440) are provided for each manifold (110), and the opening amount of the flow control valve (440) is controlled to adjust the flow amount of the electrode slurry. For reference, the drawing does not depict a control unit that controls the opening amount of the flow control valve (440), and since the configuration of the control unit that controls the opening amount of the valve falls within the category of well-known technology, even if the drawing and description thereof are omitted, there will be no problem in understanding the present invention.

[0051] The opening amount of the plurality of flow control valves (440) is independently controlled for the corresponding manifold (110) so as to reduce the deviation in slurry loading along the width direction of the electrode in which the plurality of slits (350) are arranged in a row. In other words, when there is a difference in the slurry loading amount for each group of slits (350) assigned to each manifold (110), the opening amount of the flow control valves (440) installed in each manifold (110) is controlled differently in consideration of this deviation, thereby enabling uniform slurry loading along the entire width of the electrode.

[0052] In general, the design of the slot die (10), specifically, the arrangement of the slurry pipe (400), the design of the pressurized fastening structure of the first body (100) and the second body (200), etc., are made to be symmetrical with respect to the widthwise center of the slot die (10). Accordingly, in most cases, the profile of the slurry loading is generally symmetrical with respect to the widthwise center of the slot die (10). Considering this phenomenon, the opening amount of the plurality of flow control valves (440) can be independently controlled so that the slurry flow rate is symmetrical with respect to the centers of the plurality of slits (350) arranged in a row for the plurality of manifolds (110). For example, the opening amount of the plurality of flow control valves (440) can be controlled to be the largest or smallest with respect to the manifold (110) located in the middle among the plurality of manifolds (110).

[0053] Fig. 6 is a drawing exemplarily showing a slurry loading profile according to the opening amount of each flow control valve (440) for three manifolds (110). As in the actual measurement data shown in Fig. 6, by the optimal opening amount indicated in blue, by setting the opening amount of the flow control valve (440) for the central manifold among the three manifolds (110) to the largest and symmetrically setting the opening amounts of the manifolds (110) on the left and right to be smaller than this, it is possible to implement a fairly uniform slurry loading across the entire width of the slot die (10).

[0054] It should be noted that, although the present specification exemplifies a plurality of manifolds (110) as a three-part manifold embodiment, it is obvious that the slot die (10) of the present invention can be implemented in various embodiments including a plurality of manifolds (110) having two or more parts, as well as four or more parts.

[0055]

[0056] [Second Embodiment]

[0057] In the first embodiment, a configuration is described in which slurry loading is uniformly performed along the width direction of the slot die (10) by optimizing the opening amount of a plurality of flow control valves (440) allocated to a plurality of divided manifolds (110).

[0058] And, in one embodiment of the present invention, the coater core (300) can have a divided structure of a base core (310) and a plurality of spacer cores (320). Since only the problematic spacer core (320) can be replaced or adjusted by the structure of the coater core (300) divided in this way, local slurry loading control is possible and costs, time, etc. associated with changing the coater core (300) can be reduced.

[0059] However, since the coater core (300) has a split structure, the installation of the spacer core (320) that is directly involved in slurry loading is important, and there may be variations in the installation of the spacer core (320) depending on the operator. Since variations in the installation of the spacer core (320) directly lead to variations in slurry loading, it is necessary to solve the problem of variations in the installation of the spacer core (320) along with optimizing the opening amount of the flow control valve (440). The second embodiment of the present invention relates to a structure that enables the spacer core (320) to be installed consistently at all times without the influence of the operator.

[0060] Fig. 7 is a drawing illustrating one embodiment of a structure for mounting a spacer core (320) on a first body (100). Referring to Fig. 7, the first body (100) is provided with a plurality of fixing pins (120) according to the mounting position of the spacer core (320), and the spacer core (320) is formed with a plurality of holes (322) into which the fixing pins (120) are inserted.

[0061] At least two fixed pins (120) are provided, and in the illustrated embodiment, three are provided. When arranging a plurality of fixed pins (120) in this way, it is preferable that the spacer core (320) be installed so that it can maintain the installed position without rotating, and that the installation direction is installed in only one direction, whether it is front, back, left, right, or up and down.

[0062] And, as shown in Fig. 7, the end of the fixed pin (120) slightly protrudes above the hole (322) of the spacer core (320). If the height of the fixed pin (120) is made slightly larger than the thickness of the spacer core (320), a shallow hole (not shown) into which the end of the fixed pin (120) is fitted needs to be provided on the mating surface of the second body (200). In this case, the fixed pin (120) plays a role in aligning the fastening position of the second body (200) with respect to the first body (100).

[0063] According to an embodiment, the slot die (10) may be configured to discharge an insulating liquid together with electrode slurry. To this end, as illustrated in FIG. 7, the spacer shim (320) has an insulating liquid supply hole (324) through which the insulating liquid is supplied, and a groove (326) connected to the insulating liquid supply hole (324) and extending to the tip of the spacer shim (320). The end of the groove (326) extending from the insulating liquid supply hole (324) is open. Accordingly, the electrode slurry is discharged through the slits (350) formed between the plurality of spacer shims (320), while the insulating liquid is discharged adjacent to the edge of the electrode slurry. By applying the insulating liquid to both sides of the electrode slurry, the sliding phenomenon at the edge of the electrode slurry is controlled, and the insulating performance is improved.

[0064] The groove (326) provided in the spacer core (320) may be straight or U-shaped. A straight groove (326-1) may be provided on the outermost spacer core (320) in the width direction of the slot coater, and a U-shaped groove (326-2) may be provided on the other spacer cores (320). This is related to whether the slits (350) are arranged on one or both sides in the width direction of the spacer core (320).

[0065] Insulating fluid is supplied to the insulating fluid supply hole (324) of the spacer core (320) through an insulating fluid path (not shown) formed inside the first body (100) or the second body (200). In addition, a bolt hole (328) through which a bolt (210) passes may be formed in the spacer core (320). A plurality of bolts (210) that penetrate the first body (100) are fastened to the second body (200), so that the first body (100) and the second body (200) can be pressurized and fastened to each other, and some of these bolts (210) may penetrate the spacer core (320). By positioning the spacer core (320) at the point where the fastened bolt (210) applies pressure, the strength with which the upper and lower surfaces of the spacer core (320) are in close contact with the second body (200) and the first body (100) is improved, and accordingly, the electrode slurry and the insulating liquid are effectively prevented from leaking or mixing through the joining surface of the first body (100) and the second body (200).

[0066]

[0067] The present invention has been described in more detail through drawings and examples. However, the configurations described in the drawings or examples described in this specification are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

[0068]

[0069] [Explanation of symbols]

[0070] 10: Slot die 100: First body

[0071] 110: Manifold 112: Bulkhead

[0072] 120: Fixed pin 200: Second body

[0073] 210: Bolt 300: Cotter core

[0074] 310: Base core 320: Spacer core

[0075] 322: Hole 324: Insulating fluid supply hole

[0076] 326: Groove 326-1: Straight Groove

[0077] 326-2: U-groove 328: Bolt hole

[0078] 350: Slit 400: Slurry pipe

[0079] 410: Main pipe 420: Buffer pipe

[0080] 430: Branch pipe 440: Flow control valve

Claims

1. A first body having a plurality of manifolds that are divided to independently and isolately receive electrode slurry; A second body pressurized and fastened to the first body so as to maintain the sealing of the plurality of manifolds; and A coater core that is tightly interposed between the first body and the second body to form a plurality of slits communicating with the plurality of manifolds between the joining surfaces of the first body and the second body; A slot die, including:

2. In paragraph 1, A slot die, wherein the plurality of slits are assigned to communicate with any one of the plurality of manifolds.

3. In paragraph 2, The above cotter plant, A base core sealing the rear end and both sides of the above multiple manifolds, A slot die comprising a plurality of spacer cores spaced apart from each other to form the plurality of slits at the ends of the plurality of manifolds.

4. In paragraph 3, Some of the above multiple spacer cores, A slot die arranged corresponding to at least one baffle that isolates the plurality of manifolds from each other.

5. In paragraph 1, Includes a slurry pipe that supplies slurry to the above plurality of manifolds, The above slurry pipe, A main pipe consisting of a single pipe, A buffer pipe that receives a certain volume of electrode slurry supplied from the main pipe, A plurality of branch pipes branched and connected from the above buffer pipe to correspond to the number of the plurality of manifolds, A slot die comprising a plurality of flow control valves provided for each branch pipe.

6. In paragraph 5, The above plurality of flow control valves are, A slot die in which the opening amount for a corresponding manifold is independently controlled so as to reduce the deviation in slurry loading along the width direction of an electrode having multiple slits in a row.

7. In paragraph 6, The above plurality of flow control valves are, A slot die in which the opening amount of each of the plurality of manifolds is independently controlled so that the slurry flow rate is symmetrical with respect to the center of the plurality of slits in a row.

8. In paragraph 7, The above plurality of flow control valves are, A slot die in which the opening amount of the manifold located in the middle among the above-mentioned plurality of manifolds is controlled to be the largest or smallest.

9. In paragraph 3, The above first body is provided with a plurality of fixing pins at the mounting positions of the spacer core, A slot die having a plurality of holes formed in the spacer core into which the fixed pins are inserted.

10. In paragraph 3, The above spacer plant, An insulating liquid supply hole through which insulating liquid is supplied, A slot die having a groove connected to the above insulating liquid supply hole and extending to the tip of the spacer core.

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