Insulating liquid supply device

Abstract

The present invention relates to an insulating liquid supplying device. More specifically, the insulating liquid supplying device of the present invention includes an insulating liquid tank that stores insulating liquid, a slot die that discharges the insulating liquid to the outside, an insulating liquid header that is located above the slot die and transfers the insulating liquid transferred from the insulating liquid tank to the slot die, piping that connects the insulating liquid tank, the slot die, and the insulating liquid header so as to enable the transfer of the insulating liquid, and a transfer pump that is provided on the piping and transfers the insulating liquid from the insulating liquid tank to the slot die.

Description

[Technical field]

[0001] The present invention relates to an insulating liquid supplying device, and more particularly to an insulating liquid supplying device suitable for simultaneous coating of insulating liquid in multiple rows.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0033402 dated March 17, 2022, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] Lithium secondary batteries and the like use electrodes in which an active material and an insulating layer are formed on the surface of a current collector. Such electrodes are manufactured by applying an electrode slurry containing an active material and an insulating liquid containing an insulating material to the surface of a current collector using a coating device such as a slot die so that the corners of the electrode mixture layer partially overlap, and then drying the applied material.

[0004] The insulating liquid is applied to both edges in the width direction of the electrode slurry applied to the current collector, but when the electrode slurry is applied to the electrode in multiple rows, the insulating liquid is also applied in multiple rows accordingly. For simultaneous multiple row coating, as shown in Figure 1, multiple transfer pipes are connected in parallel to the slot die to the insulating liquid tank that stores the insulating liquid, and a transfer pump is provided for each transfer pipe to transfer the insulating liquid.

[0005] 1, even if all the transfer pumps 300' pump a constant flow rate, differences in the flow rates of the insulating liquid 10' delivered from each transfer pipe 200' to the slot die 400' may occur depending on the difference in the distance from the insulating liquid tank 100' to the transfer pumps 300', the length of the transfer pipe 200', the distance from the transfer pumps 300' to the slot die 400', etc. For example, the flow rate of the insulating liquid 10' discharged from the transfer pipe 200' with the largest pressure loss may be significantly reduced.

[0006] Furthermore, in an actual manufacturing site, it is difficult for all transfer pumps to transfer insulating liquid at the same flow rate, so that the flow rate non-uniformity of the insulating liquid finally discharged from the slot die may be further aggravated. In consideration of such a problem of non-uniform flow rate, it is not easy from the viewpoint of production management to individually set the discharge flow rate of each transfer pump. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Korean Patent No. 10-2035822 Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to solve the problem of uneven flow rate of insulating liquid transported in an insulating liquid supplying device for supplying insulating liquid to a multi-row simultaneous coating slot die.

[0009] Other objects and advantages of the present invention can be understood from the following description and will become more clearly apparent from the embodiments of the present invention. Also, it is easily understood that the objects and advantages of the present invention can be realized by the means and combinations thereof as set forth in the claims. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, according to the present invention, there is provided an insulating liquid supplying device for supplying insulating liquid to a slot die for simultaneous coating in multiple rows, comprising an insulating liquid tank for storing insulating liquid, a cylindrical insulating liquid header for storing insulating liquid transferred from the insulating liquid tank and transmitting the stored insulating liquid to the slot die, a transfer pipe connecting the insulating liquid tank and the insulating liquid header so that the insulating liquid can be transferred, a plurality of supply pipes connecting the insulating liquid header and the slot die, and a transfer pump provided on the transfer pipe and providing pressure so that the insulating liquid in the insulating liquid tank is transferred to the slot die, wherein the supply pipe is connected to an upper portion of the insulating liquid header.

[0011] Specifically, the insulating liquid header may be formed to extend along the width direction of the slot die.

[0012] The insulating liquid header may be formed to extend horizontally with the slot die.

[0013] Also, the supply pipe may be led out from the top of the insulating liquid header and connected to a slot die.

[0014] More specifically, the supply pipes may be arranged along a direction in which the insulating liquid header extends, and connect the insulating liquid header and the slot die.

[0015] Additionally, the length and inner diameter of each of the supply pipes may be the same.

[0016] Moreover, the pressure loss in each of the supply pipes may be the same.

[0017] On the other hand, the pressure loss in the insulating liquid header may be less than the pressure loss in the supply pipe.

[0018] Moreover, the pressure loss in the insulating liquid header and the supply pipe can satisfy the condition of the following formula 1.

[0019] [Formula 1] (ΔPh / n)<ΔPs*5%

[0020] In the above formula 1, n is the number of transfer pipes connected to the insulating liquid header, the above ΔPh is the pressure loss inside the insulating liquid header, and the above ΔPs is the pressure loss value of one supply pipe.

[0021] Also, the transfer piping may be connected to a lower portion of the insulating liquid header.

[0022] Meanwhile, according to another embodiment, the transfer pipe may include a main transfer pipe connected to an insulating liquid tank, and an auxiliary transfer pipe branched from the main transfer pipe and connected to the insulating liquid header.

[0023] Specifically, at least two or more auxiliary transfer pipes may be branched in parallel from the main transfer pipe, and the branched auxiliary transfer pipes may be connected to the insulating liquid header, respectively.

[0024] More specifically, the transfer pumps may be provided in each of the auxiliary transfer lines.

[0025] According to the present invention, there is provided a slot die including a plurality of outlets on one side for discharging insulating liquid, connected to an insulating liquid header containing insulating liquid, and connected to the insulating liquid header and a plurality of supply pipes so that insulating liquid is supplied from each supply pipe. Effect of the Invention

[0026] According to the present invention, it is possible to almost completely eliminate deviations in the flow rate of insulating liquid transferred to the slot die through multiple pipes, and to uniformly maintain the discharge pressure of each insulating liquid discharged from the slot die through multiple nozzles. [Brief description of the drawings]

[0027] [Figure 1] This is a conventional insulation coating liquid supply device for simultaneous coating of multiple rows. [Diagram 2] 1 shows an insulating liquid coating device according to a first embodiment of the present invention. [Diagram 3] FIG. 2 is a plan view of an insulating liquid header of the insulating liquid coating apparatus according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view of the insulating liquid header of FIG. 3. [Diagram 5] 5 is an insulating liquid coating device according to a second embodiment of the present invention. [Figure 6] 13 shows an insulating liquid coating device according to a third embodiment of the present invention. [Figure 7] 11 is an insulating liquid coating device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, detailed configurations of the present invention will be described in detail with reference to the attached drawings and various embodiments. The embodiments described below are illustratively shown to facilitate understanding of the present invention, and the attached drawings are not drawn to actual scale to facilitate understanding of the invention, and the dimensions of some components may be exaggerated.

[0029] Since the present invention can be modified in various ways and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text, but it is not intended to limit the present invention to the specific disclosed forms, and it is understood that the present invention includes all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0030] The insulating liquid supplying device 100 according to the present invention supplies insulating liquid 10 using a slot die 200 for simultaneous coating in multiple rows, which can simultaneously supply insulating liquid to both sides of an electrode active material. That is, the present invention relates to a device for supplying insulating liquid 10 using a slot die 200 that simultaneously ejects and coats insulating liquid 10 in multiple rows.

[0031] Specifically, the insulating liquid supplying device 100 of the present invention is composed of an insulating liquid tank 110, an insulating liquid header 120, transfer piping 130, supply piping 140 and a transfer pump 150, and is characterized in that the insulating liquid 10 transferred from the insulating liquid tank 110 by the insulating liquid header 120 is uniformly transmitted to the slot die 200 via the supply piping 140.

[0032] The insulating liquid supplying device 100 of the present invention will be described below with reference to FIGS.

[0033] (First embodiment) Figure 2 shows an insulating liquid supplying apparatus 100 according to the first embodiment of the present invention, Figure 3 shows a plan view of an insulating liquid header 120 of the insulating liquid supplying apparatus 100 of Figure 2, and Figure 4 is a cross-sectional view of the insulating liquid header 120 of Figure 3.

[0034] As shown in FIG. 2, the insulating liquid supplying device 100 according to the first embodiment of the present invention includes an insulating liquid tank 110, an insulating liquid header 120, a transfer pipe 130, a supply pipe 140, and a transfer pump 150.

[0035] The insulating liquid tank 110 contains the insulating liquid 10 required for coating, and discharges a certain amount of the contained insulating liquid 10 and transfers it to the slot die 200 .

[0036] The insulating liquid tank 110 may be additionally provided with an agitator for agitating the contained insulating liquid 10, and the agitator may be composed of an impeller and a stirring motor for driving the impeller.

[0037] The insulating liquid tank 110 includes a discharge port (not shown) at a lower portion thereof through which the insulating liquid 10 is discharged, and the discharge port is connected to a transfer pipe 130 which serves as a passage through which the insulating liquid 10 moves.

[0038] The insulating liquid 10 discharged from the insulating liquid tank 110 can move to the slot die 200 by external pressure.

[0039] In the insulating liquid supplying apparatus 100 of the present invention, the transfer pump 150 provided in the transfer pipe 130 can provide the external pressure. That is, the insulating liquid 10 contained in the insulating liquid tank 110 can move to the opposite side through the transfer pipe 130 by the pumping pressure applied by the transfer pump 150.

[0040] The flow rate (flow velocity) of the transferred insulating liquid 10 may vary depending on the pumping pressure provided by the transfer pump 150. In addition, the degree of pressure loss may vary depending on the length and inner diameter of the transfer pipe 130. That is, even if the same pumping pressure is applied, the length and inner diameter of the transfer pipe 130 may affect the flow rate (flow velocity) of the insulating liquid 10.

[0041] The slot die 200 for simultaneous coating in multiple rows used in the present invention discharges the insulating liquid 10 in multiple rows to form an insulating layer. Therefore, the slot die 200 may be provided with multiple discharge ports (or nozzles) (not shown), and each of the discharge ports is connected to a corresponding discharge passage 210.

[0042] The multi-row simultaneous coating slot die 200 has an advantage of high process efficiency since it can form multiple insulating layers in one operation. However, if the flow rates (flow velocities) of the insulating liquid 10 discharged simultaneously through each outlet are different, a problem may occur in that the loading amount of the insulating layer formed by the slot die 200 is not uniform. Therefore, it is preferable that the inner diameter and length of each outlet passage 210 formed in the slot die 200 are all the same.

[0043] The insulating liquid header 120 stores the insulating liquid 10 transferred from the insulating liquid tank 110 , and transmits the stored insulating liquid 10 to the slot die 200 .

[0044] The insulating liquid header 120 and the insulating liquid tank 110 are connected by a transfer pipe 130 , and the insulating liquid 10 contained in the insulating liquid tank 110 can be transferred to the insulating liquid header 120 via the transfer pipe 130 .

[0045] In addition, the insulating liquid header 120 and the slot die 200 are connected by a supply pipe 140, and the insulating liquid 10 contained in the insulating liquid header 120 can be transferred to the slot die 200 via the supply pipe 140. At this time, the supply pipe 140 connected to the slot die 200 is specifically connected to the discharge passage 210 of the slot die 200. That is, the number of supply pipes 140 connected to the slot die 200 can be limited by the number of discharge passages 210 formed in the slot die 200.

[0046] The insulating liquid header 120 is preferably cylindrical so that the flow rate (flow velocity) of the insulating liquid 10 transferred through the internal receiving space can be stably maintained and pressure loss can be minimized.

[0047] 2 and 3, the insulating liquid header 120 of the present invention is formed to extend along the width direction D of the slot die 200. Specifically, the insulating liquid header 120 is located at the upper part of the slot die 200 and is formed to extend while maintaining a horizontal position with respect to the slot die 200.

[0048] Each supply pipe 140 connected to the insulating liquid header 120 may be arranged along the direction in which the insulating liquid header 120 extends. Specifically, the plurality of supply pipes 140 are sequentially connected to the insulating liquid header 120 at a predetermined interval. At this time, it is preferable that the length and inner diameter of each supply pipe 140 are the same so that the flow rate of the insulating liquid 10 transferred through each supply pipe 140 is uniform. That is, the specifications of each supply pipe 140 are unified so that the pressure loss value in each supply pipe 140 is the same. In addition, it is preferable that the supply pipes 140 are the same in all other factors that may affect the pressure loss, such as the material.

[0049] The insulating liquid header 120 may be provided at a position spaced apart from the slot die 200 by a predetermined distance as shown in FIG. 2, but is not limited thereto and may be attached to the slot die 200.

[0050] Fig. 4 shows a cross section of the insulating liquid header 120 of Fig. 3. Referring to Fig. 3 and Fig. 4, the insulating liquid header 120 has an inlet 121 through which the insulating liquid 10 flows in at a lower part, and an outlet 122 through which the insulating liquid 10 flows out to the slot die 200 at an upper part.

[0051] A transfer pipe 130 connecting the insulating liquid tank 110 and the insulating liquid header 120 is connected to an inlet 121 of the insulating liquid header 120, and a supply pipe 140 connecting the insulating liquid header 120 and the slot die 200 is connected to an outlet 122 of the insulating liquid header 120. At this time, the transfer pipe 130 is connected to a lower part of the insulating liquid header 120, and the supply pipe 140 is connected to an upper part of the insulating liquid header 120.

[0052] The transfer pipe 130 is preferably connected to a height H2 that is less than half the height (inner diameter size) H1 of the insulating liquid header 120, and more preferably connected to a height point that is less than 30% of the height H1 of the insulating liquid header 120. By forming the transfer pipe 130, i.e., the inlet 121, at a low position of the insulating liquid header 120 in this manner, it is possible to obtain an effect of moving air bubbles (gas) generated in the insulating liquid header 120 to the upper part of the insulating liquid header 120 and removing them.

[0053] If the gas generated in the insulating liquid header 120 is not smoothly discharged, the remaining gas may hinder the flow rate (flow speed) of the insulating liquid 10 or cause the loading amount of the insulating liquid 10 to be uneven when the insulating liquid 10 is discharged. Therefore, the transfer pipe 130 is connected to the lower part of the insulating liquid header 120, and the supply pipe 140 is connected to the upper part of the insulating liquid header 120, so that small gases are removed from the insulating liquid header 120 as the insulating liquid 10 is transferred. At this time, in order to further enhance the gas discharge effect, it is preferable that the supply pipe 140 is connected to the top of the insulating liquid header 120.

[0054] In this regard, the insulating liquid supplying device 100 of the present invention may further include a gas exhaust valve capable of discharging gas at an upper portion of the insulating liquid header 120. That is, gas such as air generated inside the insulating liquid header 120 may be discharged to the outside via the gas exhaust valve.

[0055] The insulating liquid 10 flowing in through the transfer pipe 130 passes through the internal storage space of the insulating liquid header 120 and flows out simultaneously through a plurality of supply pipes 140 .

[0056] The present invention aims to adjust the flow rate (flow velocity) of the insulating liquid 10 flowing out through each of the supply pipes 140 so that it is constant, and to enable the insulating liquid 10 to be uniformly ejected through each outlet of the slot die 200.

[0057] Therefore, in order to make the flow rate (flow speed) of the insulating liquid 10 transferred through each supply pipe 140 uniform, it is preferable that the heights at which the outlets 122 are formed in the insulating liquid header 120 are all the same.

[0058] Furthermore, the insulating liquid supplying device 100 of the present invention adjusts the flow rate (flow velocity) of the insulating liquid 10 being moved to be the same in all of the supply pipes 140 by drastically increasing the pressure loss in the insulating liquid header 120 in the multiple supply pipes 140 connected to the insulating liquid header 120. For example, even if the supply pipes 140 connected to the insulating liquid header 120 have the same specifications and are at the same height, a difference in the flow rate of the insulating liquid 10 in each supply pipe 140 may occur depending on the transfer pipe 130, i.e., the distance of the outlet 122 from the inlet 121 of the insulating liquid header 120.

[0059] In the insulating liquid supplying device 100 according to the first embodiment of the present invention, the shape of the supply pipe 140 is modified to increase the pressure loss in the supply pipe 140. Specifically, as shown in Fig. 2 and Fig. 4, the supply pipe 140 has a U-shaped structure in which the supply pipe 140 is led out from an upper part of the insulating liquid header 120, turns downward and is connected to the slot die 200. More preferably, the supply pipe 140 is led out from an upper part of the insulating liquid header 120 and is connected to the slot die 200.

[0060] A difference in flow rate (flow velocity) in the supply pipe 140 may occur depending on a position to which the supply pipe 140 is connected in the upper part of the insulating liquid header 120. For example, when the supply pipe 140 is connected to about 60% of the height of the insulating liquid header 120, the insulating liquid 10 transferred to the supply pipe 140 near the inlet 121 of the insulating liquid header 120 may receive a relatively stronger pumping pressure from the transfer pump 150. In this case, a problem may occur in which the flow rate (flow velocity) of the insulating liquid 10 in the supply pipe 140 differs from that of the other supply pipes 140. Therefore, in order to minimize the relative influence of the transfer pump 150 as described above, the supply pipe 140 is preferably connected to the top of the insulating liquid header 120.

[0061] In the insulating liquid supplying apparatus 100 of the present invention, it is preferable that the pressure loss in the insulating liquid header 120 and the supply piping 140 satisfies the condition of the following formula 1.

[0062] [Formula 1] (ΔPh / n)<ΔPs×5%

[0063] In the above formula 1, n is the number of transfer pipes 130 connected to the insulating liquid header 120 , the above ΔPh is the pressure loss inside the insulating liquid header 120 , and the above ΔPs is the pressure loss value of the supply pipe 140 .

[0064] The insulating liquid header 120 and supply pipe 140 included in the insulating liquid supplying apparatus 100 according to the first embodiment of the present invention are preferably adjusted in volume, shape, position, inner diameter, length, etc. within a range that satisfies formula 1 above.

[0065] Second embodiment The insulating liquid supplying device 100 according to the second embodiment is arranged so that the insulating liquid header 120 is located below the slot die 200.

[0066] FIG. 5 shows an insulating liquid supplying device 100 according to a second embodiment of the present invention.

[0067] As shown in FIG. 5, the insulating liquid supplying device 100 of the second embodiment is arranged so that the insulating liquid header 120 is located at the bottom of the slot die 200, and the supply piping 140 is led out from the top of the insulating liquid header 120 and connected to the slot die 200.

[0068] Since the supply pipe 140 extends vertically, the resistance experienced by the transferred insulating liquid 10 may be smaller than that of the first embodiment. Therefore, the inner diameter of the supply pipe 140 of the insulating liquid supplying device 100 according to the second embodiment may be smaller than that of the supply pipe 140 of the insulating liquid supplying device 100 according to the first embodiment, and the length of the supply pipe 140 may be longer than that of the supply pipe 140 of the insulating liquid supplying device 100 according to the first embodiment. Alternatively, the volume of the insulating liquid header 120, the inner diameter and length of the transfer pipe 130, and the like may be manipulated so that the pressure loss in the insulating liquid header 120 is lower than the pressure loss in the insulating liquid header 120 of the insulating liquid supplying device 100 according to the first embodiment.

[0069] Third embodiment In the insulating liquid supplying device 100 according to the third embodiment, an insulating liquid header 120 is located on the rear surface of a slot die 200 and is disposed below the slot die 200.

[0070] FIG. 6 shows an insulating liquid supplying device 100 according to a third embodiment of the present invention.

[0071] As shown in FIG. 6, the supply piping 140 of the insulating liquid supplying device 100 according to the third embodiment is led out vertically from the top of the insulating liquid header 120 and then bent horizontally again toward the rear surface of the slot die 200 and connected thereto.

[0072] The supply pipe 140 having such a structure may have a smaller pressure loss than the first embodiment, but may have a larger pressure loss than the second embodiment.

[0073] (Fourth embodiment) In the insulating liquid supplying device 100 of the present invention, the insulating liquid 10 can be supplied to the insulating liquid header 120 via a plurality of transfer pipes 130 each equipped with a transfer pump 150. In other words, by increasing the number of paths through which the insulating liquid 10 is transferred to a plurality of paths and providing each of the transfer pipes 130 with a transfer pump 150, it becomes possible to transfer the insulating liquid 10 within a short period of time.

[0074] FIG. 7 shows an insulating liquid supplying device 100 according to a fourth embodiment of the present invention.

[0075] As shown in Fig. 7, in the insulating liquid supplying device 100 according to the fourth embodiment of the present invention, the insulating liquid 10 is transferred from the insulating liquid tank 110 to the slot die 200 by a transfer pump 150 connected to a plurality of pipes. Specifically, the transfer pipe 130 includes a main transfer pipe 131 connected to the insulating liquid tank 110, and an auxiliary transfer pipe 132 branched from the main transfer pipe 131 and connected to the insulating liquid header 120. More specifically, at least two or more auxiliary transfer pipes 132 may be branched in parallel from the main transfer pipe 131, and each of the branched auxiliary transfer pipes 132 is connected to the insulating liquid header 120. In this case, the transfer pump 150 may be provided in each of the auxiliary transfer pipes 132.

[0076] Referring to FIG. 7, three auxiliary transfer pipes 132 are connected to one main transfer pipe 131, and three transfer paths are formed in the branched auxiliary transfer pipes 132.

[0077] The insulating liquid 10 can be transferred to the insulating liquid header 120 via the three transfer paths, but in this case, the pressure loss may differ for each auxiliary transfer pipe 132 due to differences in the distances of the transfer paths. That is, the multiple auxiliary transfer pipes 132 may be designed to have different lengths depending on the situation. In this case, the flow rate (flow velocity) of the insulating liquid 10 transferred via each auxiliary transfer pipe 132 is different.

[0078] However, the insulating liquid supplying device 100 of the present invention primarily buffers the above difference by temporarily storing the insulating liquid 10 transferred through each auxiliary transfer pipe 132 in one space, the insulating liquid header 120. Also, secondarily, the pressure loss of the supply pipe 140 is extremely increased, so that the insulating liquid 10 can be transferred at the same flow rate (flow velocity) between each of the multiple connected supply pipes 140.

[0079] The insulating liquid supplying device 100 of the present invention can overcome the phenomenon of non-uniform flow rate caused by differences in the length of the transfer pipes 130 by adding an insulating liquid header 120 configuration. In addition, by limiting the position of the supply pipes 140, it is possible to overcome the phenomenon of non-uniform flow rate that may newly occur due to the insulating liquid header 120 configuration.

[0080] In addition, the insulating liquid supply device 100 of the present invention has the effect of offsetting the flow rate difference generated by the transfer pipe 130, the insulating liquid header 120, etc., by intentionally increasing the pressure loss in the supply piping 140, thereby making the flow rate of the insulating liquid 10 transferred from the insulating liquid header 120 to each supply pipe 140 uniform.

[0081] 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. [Explanation of symbols]

[0082] 10': (Prior Art) Insulating Liquid 100': (Prior Art) Insulated Liquid Tank 200': (Prior Art) Transfer Pipe 300': (Prior Art) Transfer Pump 400': (conventional technology) slot die 10: Insulating liquid 100: Insulating liquid supply device 110: Insulating liquid tank 120: Insulating fluid header 121:Inlet 122: Outlet 130:Transport piping 131: Main transfer pipe 132: Auxiliary transfer piping 140: Supply piping 150:Transfer pump 200: Slot die 210:Discharge path D: Width direction

Claims

1. An insulating liquid supplying device for supplying insulating liquid to a slot die for simultaneous multi-row coating, comprising: an insulating liquid tank for containing an insulating liquid; a cylindrical insulating liquid header that accommodates the insulating liquid transferred from the insulating liquid tank and transfers the accommodated insulating liquid to a slot die; a transfer pipe that connects the insulating liquid tank and the insulating liquid header so as to enable transfer of the insulating liquid; a plurality of supply pipes connecting the insulating liquid header and the slot die; a transfer pump provided in the transfer piping and applying pressure so that the insulating liquid in the insulating liquid tank is transferred to the slot die; the supply pipe is connected to an upper portion of the insulating liquid header, The insulating liquid supply device, wherein a pressure loss in the insulating liquid header is smaller than a pressure loss in the supply pipe.

2. The insulating liquid supplying device according to claim 1 , wherein the insulating liquid header extends along a width direction of the slot die.

3. The insulating liquid supplying device according to claim 1 or 2, wherein the insulating liquid header extends horizontally to the slot die.

4. 3. The insulating liquid supplying device according to claim 1, wherein the plurality of supply pipes are led out from a top portion of the insulating liquid header and connected to a slot die.

5. The insulating liquid supplying device according to claim 2 , wherein each supply pipe is arranged along a direction in which the insulating liquid header extends, and connects the insulating liquid header and the slot die.

6. 3. The insulating liquid supplying apparatus according to claim 1, wherein the plurality of supply pipes have the same length and inner diameter.

7. 3. The insulating liquid supplying device according to claim 1, wherein the pressure losses in the plurality of supply pipes are all the same.

8. The pressure loss of the insulating liquid header and the pressure loss of the supply pipe satisfy the condition of the following formula 1, [Formula 1] (ΔPh / n)<ΔPs×5% 3. The insulating liquid supply device according to claim 1, wherein in the formula 1, n is the number of transfer pipes connected to the insulating liquid header, ΔPh is the pressure loss inside the insulating liquid header, and ΔPs is the pressure loss value of one supply pipe.

9. 3. The insulating liquid supplying device according to claim 1, wherein the transfer pipe is connected to a lower portion of the insulating liquid header.

10. 3. The insulating liquid supply device according to claim 1, wherein the transfer piping is composed of a main transfer piping connected to the insulating liquid tank, and an auxiliary transfer piping branched off from the main transfer piping and connected to the insulating liquid header.

11. The insulating liquid supplying device according to claim 10, wherein two or more auxiliary transfer pipes are branched in parallel from the main transfer pipe, and the two or more auxiliary transfer pipes are each connected to the insulating liquid header.

12. The insulating liquid supplying apparatus according to claim 11 , wherein the transfer pump is provided for each of the two or more auxiliary transfer pipes.

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