JP5955443B1 - Film manufacturing method and film manufacturing apparatus - Google Patents

Abstract

An object of the present invention is to remove unnecessary substances from a film while eliminating defects occurring in the film being cleaned. A film cleaning method includes a step of transporting a heat-resistant separator (S) in a longitudinal direction so that the heat-resistant separator (S) passes through a cleaning water (W) of a cleaning tank (15), and a cleaning water ( W) is introduced into the cleaning tank (15) from the inner wall of the cleaning tank (15) facing the end portion in the width direction of the heat-resistant separator (S) and discharged upward or downward. [Selection] Figure 7

Description

  The present invention relates to a film manufacturing method and a film manufacturing apparatus such as a separator used in a battery such as a lithium ion secondary battery.

  In the lithium ion secondary battery, the positive electrode and the negative electrode are separated by a film-like and porous separator. The manufacturing process of this separator includes a cleaning process for later removing unnecessary substances from the film once formed.

  As a technique for cleaning a sheet or a film, for example, techniques disclosed in Patent Documents 1 and 2 are known unless limited to separators. Patent document 1 is disclosing the washing tank of 2 tanks which carries out rough washing | cleaning and this washing | cleaning in order of a heat-sealable multilayered sheet. Patent Document 2 discloses a multi-stage cleaning unit that sequentially immerses and sprays optical plastic films.

JP 2001-170933 A (released on June 26, 2001) Japanese Patent Application Laid-Open No. 2007-105662 (released on April 26, 2007)

  The porous separator and its intermediate product film have lower mechanical strength than a simple non-porous film. For this reason, problems such as breakage, wrinkling, and tearing often occur in these manufacturing processes, particularly in the cleaning process. However, Patent Documents 1 and 2 do not fully examine this problem. An object of the present invention is to remove unnecessary substances from a film while eliminating problems occurring in the film being cleaned.

  In order to solve the above problems, the film manufacturing method of the present invention includes a step of conveying the film in the longitudinal direction so that the film passes through the liquid in the liquid tank, and the cleaning liquid in the width direction of the film. And introducing into the liquid tank from the inner wall of the liquid tank facing the end of the liquid and discharging it upward or downward.

  When a new force is applied to the film in the cleaning liquid from a direction different from the film conveyance direction, problems such as folds, wrinkles, and tears may occur.

  According to the manufacturing method, the cleaning liquid flows upward or downward in the vicinity of the inner wall of the liquid tank facing the end in the width direction of the film. For this reason, the cleaning liquid flows between the film and the inner wall. Therefore, the force applied to the film by the flowing cleaning liquid pressing the film surface is suppressed. In addition, the cleaning liquid on the film surface is updated, and the removal of the substance to be removed from the film is promoted. Therefore, it is possible to manufacture a film in which the residue of the substance to be removed is suppressed while suppressing problems occurring in the film. The “film width direction” means a direction perpendicular to the longitudinal direction and the thickness direction of the film.

  Further, in the film manufacturing method of the present invention, in the discharging step, the liquid is introduced into the liquid tank by a discharge portion protruding from the inner wall, and a discharge port provided on the upper side or the lower side of the discharge portion. It is desirable to discharge from.

  According to the manufacturing method, the discharge unit can discharge the liquid via the discharge port so that the liquid flows reliably in the vicinity of the inner wall of the liquid tank facing the end in the width direction of the film.

  In the film manufacturing method of the present invention, in the discharging step, a direction in which the liquid is discharged from the discharge port is a straight line extending in the discharge direction between the film and the inner wall in the liquid. It is desirable to be set to pass through.

  According to the said manufacturing method, since the liquid passes between the film and the inner wall of the liquid tank which opposes the edge part of the width direction of a film, it can change from the one surface side of a film to the other surface side.

  In the film manufacturing method of the present invention, in the discharging step, it is preferable that the discharging direction is set so that the film does not exist in the liquid on the straight line.

  According to the manufacturing method, the liquid can be switched from one side of the film to the other side while reliably suppressing the force applied to the film by the flowing liquid pushing the film surface.

  In the film manufacturing method of the present invention, in the transporting step, the film is transported by a roller, and in the discharging step, the discharge port is perpendicular to a rotation axis of the roller in the discharge unit. It is desirable to be provided on the direction side.

  Moreover, in the film manufacturing method of this invention, it is desirable in the said discharge process that the said discharge part is extended along the said inner wall.

  According to the manufacturing method, the liquid is arranged so as to flow in the vicinity of the inner wall of the liquid tank in the discharge portion immediately before being discharged from the discharge portion. For this reason, after the liquid is discharged from the discharge portion, it can surely flow in the vicinity of the inner wall of the liquid tank facing the end portion in the width direction of the film.

  Moreover, in the film manufacturing method of this invention, in the said discharge process, it is desirable for the said discharge port to spread in the direction where the said inner wall is extended.

  According to the manufacturing method, the liquid is discharged at a substantially uniform flow rate from the discharge port that spreads in the direction in which the inner wall extends. For this reason, after being discharged from the discharge port, the liquid can flow in the vicinity of the inner wall of the liquid tank facing the end in the width direction of the film at a uniform flow rate in the direction in which the inner wall extends.

  Moreover, in the film manufacturing method of this invention, it is desirable to supply the said liquid in the said liquid tank by the said some discharge part in the said discharge process.

  According to the manufacturing method, the liquid can flow in the vicinity of the inner wall of the liquid tank facing the end in the width direction of the film at a plurality of positions corresponding to the plurality of ejection units. Therefore, more liquid on the film surface is renewed, and the removal of the substance to be removed from the film is further promoted.

  In the film manufacturing method of the present invention, it is desirable that the liquid supply sources of the plurality of ejection units are integrated in the ejection step.

  According to the manufacturing method, the liquid is discharged from the plurality of discharge portions at a substantially uniform flow rate. For this reason, the liquid can flow in the vicinity of the inner wall of the liquid tank facing the end in the width direction of the film at a uniform flow rate after being discharged from the plurality of discharge portions.

  Moreover, in the film manufacturing method of this invention, the said liquid is attracted | sucked from the position near the inner wall facing the inner wall which introduces the said liquid of the said liquid tank rather than the inner wall which introduces the said liquid in the bottom face of the said liquid tank. It is desirable to further include a step, and in the step of discharging, the liquid is discharged upward.

According to the manufacturing method, the liquid circulates in the liquid tank as follows.
(1) The liquid flows in one direction near the inner wall (hereinafter referred to as “introduction inner wall”) for introducing the liquid in the liquid tank by being discharged.
(2) The liquid flows from the introduction inner wall to the inner wall of the liquid tank facing the introduction inner wall (hereinafter referred to as “opposing inner wall”).
(3) When the liquid is sucked, the liquid flows in the direction opposite to the one direction described above near the opposing inner wall.
(4) The liquid flows from the opposing inner wall to the introduction inner wall.
Thereby, the liquid can circulate the whole liquid tank. For this reason, the renewal of the liquid of the whole surface of a film is accelerated | stimulated.

  In the film manufacturing method of the present invention, the step of sucking the liquid from a position closer to the liquid level of the liquid than the bottom of the liquid tank on the inner wall of the liquid tank facing the inner wall into which the liquid is introduced. In the step of discharging, it is preferable that the liquid is discharged downward. Also according to the manufacturing method, the liquid can circulate through the entire liquid tank.

  Moreover, in the film manufacturing method of this invention, it is desirable for the bottom face of the said liquid tank to incline.

  According to the manufacturing method, the liquid flows in the tilt direction. For this reason, at the time of maintenance, the liquid can be discharged from the liquid tank without leaving the liquid in the liquid tank.

  Moreover, in the film manufacturing method of this invention, it is desirable to further include the process of attracting | sucking the said liquid from the low side of the said bottom face, where the bottom face of the said liquid tank is inclined.

  According to the said manufacturing method, the deposit which generate | occur | produced in the liquid tank gathers in the direction where the bottom face of the liquid tank became low. Therefore, the precipitate collects toward the position where the liquid is sucked. At this time, the precipitate can be removed by filtering the sucked liquid.

  Moreover, in the film manufacturing method of this invention, the said bottom face is lower than the position side which carries the said film into the said liquid tank in the said conveyance process from the position side which carries out the said film from the said liquid tank in the said conveyance process. It is desirable that

  Moreover, in the film manufacturing method of the present invention, in the transporting step, the film is transported in the longitudinal direction so that the film passes through the liquids of the first and second liquid tanks, and in the discharging step, The liquid is introduced into the first liquid tank from the inner wall of the first liquid tank facing the end in the width direction of the film and discharged upward or downward, and the liquid is discharged in the width direction of the film. Introducing the second liquid tank into the second liquid tank from the inner wall of the second liquid tank facing the end, discharging the liquid upward or downward, and moving the liquid from the second liquid tank to the first liquid tank; It is desirable to include further.

  According to the manufacturing method described above, a part of the liquid does not hinder the flow of the liquid in the vicinity of the inner walls of the first and second liquid tanks facing the end in the width direction of the film, and the first liquid tank and the second liquid tank. It can move between liquid tanks. Further, for example, floating substances can be removed in the liquid movement path between the first liquid tank, the second liquid tank, and the liquid tank. Thereby, it can suppress that the suspended | floating matter of a 2nd liquid tank flows into a 1st liquid tank.

  Another film manufacturing method of the present invention includes a step of conveying the film in the longitudinal direction so that the film passes through the liquid in the liquid tank, and the width direction of the film on the bottom surface of the liquid tank. And introducing into the liquid tank from a position closer to either one of the two inner walls of the liquid tank facing the end of the liquid tank, and discharging upward.

  The film manufacturing apparatus of the present invention includes a liquid tank, a transport apparatus that transports the film in the longitudinal direction so that the film passes through the liquid in the liquid tank, and the liquid in an end portion in the width direction of the film. And a discharge part for introducing the liquid tank into the liquid tank from the inner wall of the liquid tank opposed to the liquid tank and discharging the liquid tank upward or downward.

Another film manufacturing apparatus of the present invention includes a liquid tank, a transport apparatus that transports the film in the longitudinal direction so that the film passes through the liquid in the liquid tank, and the liquid on the bottom surface of the liquid tank. A discharge part that introduces into the liquid tank from a position closer to either one of the two inner walls of the liquid tank facing the end in the width direction of the film, and discharges upward or downward;
Is provided.

  The present invention has an effect that it is possible to manufacture a film in which the residue of the removal target substance is suppressed while suppressing defects occurring in the film.

It is a schematic diagram which shows the cross-sectional structure of a lithium ion secondary battery. It is a schematic diagram which shows the detailed structure of the lithium ion secondary battery shown by FIG. It is a schematic diagram which shows the other structure of the lithium ion secondary battery shown by FIG. It is sectional drawing which shows the structure of the washing | cleaning apparatus used with the washing | cleaning method of Embodiment 1. FIG. It is sectional drawing which shows the periphery structure of the guide roll used with the washing | cleaning method of Embodiment 2. FIG. It is sectional drawing which shows the periphery structure of the roller used with the washing | cleaning method of Embodiment 3. It is a side sectional view, a top view, and a front sectional view showing a configuration for circulating cleaning water in the cleaning tank of the fourth embodiment. FIG. 8 is a front sectional view and a plan sectional view showing a modified example of the alternative route shown in FIG. 7. It is side surface sectional drawing which shows the structure of the pipe provided between the washing tanks of the washing | cleaning apparatus shown by FIG. It is a front sectional view and a top view showing other composition of the discharge part of the washing tub shown in FIG. FIG. 10 is a side sectional view, a plan view, and a front sectional view showing a configuration for circulating cleaning water in the cleaning tank of the fifth embodiment.

[Basic configuration]
The manufacturing method of a lithium ion secondary battery, a separator, a heat resistant separator, and a heat resistant separator will be described in this order.

(Lithium ion secondary battery)
Non-aqueous electrolyte secondary batteries represented by lithium ion secondary batteries have high energy density, and are therefore currently used for mobile devices such as personal computers, mobile phones, personal digital assistants, automobiles, airplanes, etc. As a battery, it is widely used as a stationary battery that contributes to the stable supply of electric power.

  FIG. 1 is a schematic diagram showing a cross-sectional configuration of a lithium ion secondary battery 1.

  As shown in FIG. 1, the lithium ion secondary battery 1 includes a cathode 11, a separator 12, and an anode 13. An external device 2 is connected between the cathode 11 and the anode 13 outside the lithium ion secondary battery 1. Then, electrons move in the direction A when the lithium ion secondary battery 1 is charged, and in the direction B when the lithium ion secondary battery 1 is discharged.

(Separator)
The separator 12 is disposed between the cathode 11 that is the positive electrode of the lithium ion secondary battery 1 and the anode 13 that is the negative electrode thereof so as to be sandwiched between them. The separator 12 is a porous film that allows lithium ions to move between the cathode 11 and the anode 13 while separating them. The separator 12 includes, for example, polyolefin such as polyethylene and polypropylene as its material.

  FIG. 2 is a schematic diagram showing the detailed configuration of the lithium ion secondary battery 1 shown in FIG. (C) shows a state when the temperature of the lithium ion secondary battery 1 is rapidly increased.

  As shown in FIG. 2A, the separator 12 is provided with a number of holes P. Usually, the lithium ions 3 of the lithium ion secondary battery 1 can come and go through the holes P.

  Here, for example, the lithium ion secondary battery 1 may be heated due to overcharge of the lithium ion secondary battery 1 or a large current caused by a short circuit of an external device. In this case, as shown in FIG. 2B, the separator 12 is melted or softened, and the hole P is closed. Then, the separator 12 contracts. Thereby, since the movement of the lithium ion 3 stops, the above-mentioned temperature rise also stops.

  However, when the lithium ion secondary battery 1 is rapidly heated, the separator 12 is rapidly contracted. In this case, as shown in FIG. 2C, the separator 12 may be broken. And since the lithium ion 3 leaks from the destroyed separator 12, the movement of the lithium ion 3 does not stop. Therefore, the temperature rise continues.

(Heat-resistant separator)
FIG. 3 is a schematic diagram showing another configuration of the lithium ion secondary battery 1 shown in FIG. 1, where (a) shows a normal configuration, and (b) shows that the lithium ion secondary battery 1 is abruptly changed. The state when the temperature is raised is shown.

  As shown in FIG. 3A, the separator 12 may be a heat-resistant separator including a porous film 5 and a heat-resistant layer 4. The heat-resistant layer 4 is laminated on one surface of the porous film 5 on the cathode 11 side. The heat-resistant layer 4 may be laminated on one surface of the porous film 5 on the anode 13 side, or may be laminated on both surfaces of the porous film 5. The heat-resistant layer 4 is also provided with holes similar to the holes P. Usually, the lithium ions 3 come and go through the holes P and the holes of the heat-resistant layer 4. The heat resistant layer 4 includes, for example, wholly aromatic polyamide (aramid resin) as a material thereof.

  As shown in FIG. 3B, even when the lithium ion secondary battery 1 is rapidly heated and the porous film 5 is melted or softened, the heat resistant layer 4 assists the porous film 5. Therefore, the shape of the porous film 5 is maintained. Therefore, the porous film 5 is melted or softened, and the holes P are only blocked. Thereby, since the movement of the lithium ion 3 is stopped, the above-described overdischarge or overcharge is also stopped. Thus, destruction of the separator 12 is suppressed.

(Separator / heat-resistant separator manufacturing process)
The production of the separator and the heat-resistant separator of the lithium ion secondary battery 1 is not particularly limited, and can be performed using a known method. Below, the case where the porous film 5 mainly contains polyethylene as the material is assumed and demonstrated. However, even when the porous film 5 contains other materials, the separator 12 (heat resistant separator) can be manufactured by the same manufacturing process.

  For example, after adding an inorganic filler or a plasticizer to a thermoplastic resin to form a film, the inorganic filler and the plasticizer are washed and removed with an appropriate solvent. For example, when the porous film 5 is a polyolefin separator formed from a polyethylene resin containing ultra-high molecular weight polyethylene, it can be produced by the following method.

  This method is (1) kneading to obtain a polyethylene resin composition by kneading ultrahigh molecular weight polyethylene and an inorganic filler (for example, calcium carbonate, silica) or a plasticizer (for example, low molecular weight polyolefin, liquid paraffin). A step, (2) a rolling step of forming a film using the polyethylene resin composition, (3) a removal step of removing the inorganic filler or plasticizer from the film obtained in step (2), and (4) It includes a stretching step of stretching the film obtained in the step (3) to obtain the porous film 5. In addition, the said process (4) can also be performed between the said processes (2) and (3).

  The removal step provides a large number of micropores in the film. The micropores of the film stretched by the stretching process become the above-described holes P. Thereby, the porous film 5 (separator 12 which does not have a heat-resistant layer) which is a polyethylene microporous film having a predetermined thickness and air permeability is obtained.

  In the kneading step, 100 parts by weight of ultra high molecular weight polyethylene, 5 to 200 parts by weight of a low molecular weight polyolefin having a weight average molecular weight of 10,000 or less, and 100 to 400 parts by weight of an inorganic filler may be kneaded.

  Thereafter, the heat-resistant layer 4 is formed on the surface of the porous film 5 in the coating process. For example, an aramid / NMP (N-methyl-pyrrolidone) solution (coating solution) is applied to the porous film 5 (coating step) and solidified (coagulating step), thereby heat-resistant layer 4 which is an aramid heat-resistant layer. Form. The heat-resistant layer 4 may be provided only on one side of the porous film 5 or on both sides.

  In the coating process, the surface of the porous film 5 is coated with a polyvinylidene fluoride / dimethylacetamide solution (coating liquid) (coating process) and solidified (coagulating process) to thereby form the porous film 5. An adhesive layer can also be formed on the surface. The adhesive layer may be provided only on one side of the porous film 5 or may be provided on both sides.

  In this specification, a layer having a function such as adhesion to an electrode or heat resistance equal to or higher than the melting point of polyolefin is referred to as a functional layer.

  The method for applying the coating liquid to the porous film 5 is not particularly limited as long as it is a method that enables uniform wet coating, and a conventionally known method can be employed. For example, a capillary coating method, a spin coating method, a slit die coating method, a spray coating method, a dip coating method, a roll coating method, a screen printing method, a flexographic printing method, a bar coater method, a gravure coater method, a die coater method, etc. Can do. The thickness of the heat-resistant layer 4 can be controlled by the thickness of the coating wet film and the solid content concentration in the coating solution.

  A resin film, a metal belt, a drum, or the like can be used as a support for fixing or conveying the porous film 5 during coating.

  As described above, the separator 12 (heat resistant separator) in which the heat resistant layer 4 is laminated on the porous film 5 can be manufactured. The manufactured separator is wound around a cylindrical core. In addition, the object manufactured with the above manufacturing method is not limited to a heat-resistant separator. This manufacturing method does not need to include a coating process. In this case, the object to be manufactured is a separator having no heat-resistant layer.

Embodiment 1
A first embodiment of the present invention will be described with reference to FIG.

  In the following embodiments, a method for cleaning a heat-resistant separator, which is a long and porous battery separator, is described. The heat-resistant layer of the heat-resistant separator is formed by applying an aramid / NMP (N-methyl-pyrrolidone) solution (coating solution) to a porous film. At this time, NMP (substance to be removed) as a solvent also impregnates the pores of the porous film.

  The air permeability of the heat-resistant separator in which NMP remains in the holes is lower than the air permeability of the heat-resistant separator in which NMP does not remain in the holes. The lower the air permeability, the lower the output of the lithium ion secondary battery because the movement of lithium ions in the lithium ion secondary battery using the heat-resistant separator is hindered. For this reason, it is preferable that it can wash | clean so that NMP may not remain in the hole of a heat-resistant separator.

≪Configuration to heat-resistant separator with multi-stage washing tank≫
(Washing tank)
FIG. 4 is a cross-sectional view showing the configuration of the cleaning device 6 used in the cleaning method of the present embodiment.

  As shown in FIG. 4, the cleaning device 6 includes cleaning tanks 15 to 19. The cleaning tanks 15 to 19 are each filled with cleaning water W (liquid).

  The cleaning device 6 further includes a plurality of rotatable rollers that convey the heat-resistant separator S. Among these rollers, rollers a to m are rollers that convey the heat-resistant separator S that is cleaned in the cleaning tank 15.

  The heat-resistant separator S that has been conveyed from the upstream process (for example, the coating process) of the cleaning process passes through the cleaning water W (hereinafter “water”) filled in the cleaning tank 15 via the rollers a to m. The rollers a to m (conveying rollers) define the conveying path of the heat-resistant separator S in the cleaning tank 15. In the cleaning tanks 16 to 19, the heat resistant separator S is cleaned in the same manner as the cleaning tank 15.

(Drive roller)
The cleaning device 6 further includes a driving roller R that applies a driving force to the heat-resistant separator S between the cleaning tanks and auxiliary rollers p · q. The auxiliary rollers p and q define an angle at which the heat-resistant separator S contacts the driving roller R (so-called “holding angle”). Although the drive roller R and the auxiliary rollers p and q may be arranged in water, it is preferable to arrange them between the washing tanks as shown in FIG.

  As described above, between the position of the roller a of the cleaning tank 15 (first cleaning tank) and the position of the roller of the cleaning tank 19 (second cleaning tank) corresponding to the roller m, the heat-resistant separator S The driving force for conveyance is added. Here, “the position of the roller a in the cleaning tank 15” is a position where the heat-resistant separator S is carried into the cleaning tank 15. The “position of the roller of the cleaning tank 19 corresponding to the roller m” is a position where the heat-resistant separator S is carried out from the cleaning tank 19.

  And the above-mentioned driving force is the position of the washing tank 17 side of the roller of the washing tank 16 (first washing tank) corresponding to the roller l and the washing tank 17 (second washing tank) corresponding to the roller b. It is preferable to add to the heat-resistant separator S between the position on the cleaning tank 16 side of the roller. Here, the “position on the cleaning tank 17 side of the roller of the cleaning tank 16 corresponding to the roller l” is a position where the heat-resistant separator S is carried out from the water of the cleaning tank 16. The “position of the cleaning tank 17 corresponding to the roller b on the cleaning tank 16 side of the roller” is a position where the heat-resistant separator S is carried into the water of the cleaning tank 17.

≪Operation to wash heat-resistant separator with multi-stage washing tank≫
In the cleaning method of the present embodiment, the heat-resistant separator S is transported in the longitudinal direction, and the heat-resistant separator S being transported is sequentially passed through the cleaning water W filled in the cleaning tanks 15 to 19. Cleaning. Thus, the heat-resistant separator S is sequentially conveyed from the upstream cleaning tank (first cleaning tank) to the downstream cleaning tank (second cleaning tank). Here, unless otherwise specified, “upstream” and “downstream” mean upstream and downstream in the transport direction of the separator.

  After the cleaning in the cleaning tanks 15 to 19 is completed, the heat-resistant separator S is conveyed to a downstream process (for example, a drying process) of the cleaning process.

<< Effects of this embodiment >>
(Diffusion cleaning)
By passing the heat-resistant separator S through the washing water W, NMP diffuses into the water from the holes of the heat-resistant separator S. Here, the diffusion amount of NMP increases as the NMP concentration of the cleaning water W decreases.

  Since the heat-resistant separator S is sequentially washed in the washing tanks 15 to 19, the NMP concentration of the washing water W is lower in the downstream washing tank than in the upstream washing tank. That is, since the diffusion of NMP proceeds step by step, NMP clogged in the holes can be reliably removed.

(Washing water flow direction)
As shown in FIG. 4, the cleaning water W may flow in the direction D from the downstream cleaning tank 19 to the upstream cleaning tank 15 in the separator conveyance direction. For this purpose, for example, the barrier between the cleaning tanks 15 to 19 may be lowered toward the upstream in the separator conveyance direction. At this time, in the cleaning method of the present embodiment, the cleaning water W is supplied to the downstream cleaning tank, and the cleaning water W in the downstream cleaning tank is supplied to the upstream cleaning tank. A step of renewing the cleaning water W is further included. A part of the cleaning water W is discharged from the upstream cleaning tank 15. According to this, the NMP concentration of the cleaning water W in the downstream cleaning tank in the separator transport direction can be made lower than the NMP concentration of the cleaning water W in the upstream cleaning tank while effectively using the cleaning water W. it can.

(Efficient cleaning)
By proceeding with the diffusion of NMP stepwise, it is possible to remove NMP more efficiently than cleaning with only one cleaning tank. For this reason, the conveyance distance of the heat-resistant separator S during washing | cleaning can be shortened. Therefore, the heat-resistant separator S having a lower mechanical strength than the non-porous film can be washed while suppressing problems such as bending, wrinkling, tearing and meandering.

≪Other composition≫
(Washing water circulation)
The wider the heat-resistant separator S, the higher the productivity. Therefore, the width of the heat-resistant separator S (the width in the direction perpendicular to the paper surface in FIG. 4) is often increased to near the width of the cleaning tanks 15-19. Moreover, the width | variety of the washing tanks 15-19 is designed according to the width | variety of the heat-resistant separator S. FIG.

  When the width of the heat-resistant separator S is increased and the gap between the end of the heat-resistant separator S and the cleaning tanks 15 to 19 is narrowed, the cleaning water W filled in the cleaning tanks 15 to 19 Of the cleaning tank) and the other side (both ends of the cleaning tank (left and right ends in FIG. 4)).

  In cleaning by the cleaning tanks 15 to 19, the cleaning water W is often supplied and discharged due to overflow between the cleaning tanks. At this time, the cleaning water W divided on one side of the heat-resistant separator S is supplied and discharged, but the cleaning water W divided on the other side of the heat-resistant separator S may stay.

  Therefore, in the cleaning method of the present embodiment, in at least one of the cleaning tanks 15 to 19, the cleaning water W is used to promote the replacement of the cleaning water W between the one surface side and the other surface side of the heat-resistant separator S. May be included in the process. At this time, the cleaning device 6 may further include a circulation device having a supply / discharge port for the cleaning water W in at least one of the cleaning tanks 15 to 19.

  Thereby, the NMP concentration of the cleaning water W in one cleaning tank can be made more uniform, and the efficient removal of NMP can be promoted.

(Washing water)
The cleaning water W is not limited to water and may be any cleaning liquid that can remove NMP from the heat-resistant separator S.

  Further, the cleaning water W may contain a cleaning agent such as a surfactant, an acid (for example, hydrochloric acid) or a base. And it is preferable that the temperature of the washing water W is 120 degrees C or less. At this temperature, the heat-resistant separator S is less likely to heat shrink. The temperature of the washing water W is more preferably 20 ° C. or higher and 100 ° C. or lower.

(Polyolefin separator manufacturing method)
The method for cleaning the heat-resistant separator S described above can be applied to a method for cleaning a separator (polyolefin separator) that does not have a heat-resistant layer.

  The separator is formed by molding and stretching a polyolefin resin composition obtained by kneading a high molecular weight polyolefin such as ultrahigh molecular weight polyethylene and an inorganic filler or a plasticizer. Then, the pores of the separator are formed by washing away the inorganic filler or plasticizer (substance to be removed).

  The air permeability of the separator in which the removal target substance remains in the holes without being washed away is lower than the air permeability of the separator in which the removal target substance does not remain in the holes. The lower the air permeability, the lower the output of the lithium ion secondary battery because the movement of lithium ions in the lithium ion secondary battery using the separator is hindered. For this reason, it is preferable that it can wash | clean so that the said removal target substance may not remain in the hole of a separator.

  The cleaning liquid for cleaning the separator containing the inorganic filler may be any cleaning liquid that can remove the inorganic filler from the separator. Preferably, it is an aqueous solution containing an acid or a base.

  The cleaning liquid for cleaning the separator containing the plasticizer may be any cleaning liquid that can remove the plasticizer from the separator. An organic solvent such as dichloromethane is preferred.

  To summarize the above, the method for cleaning a polyolefin resin composition (film) formed into a film is a process of transporting a long film, which is an intermediate product of a separator, in its longitudinal direction, and this film being transported, And a step of performing cleaning by sequentially passing through the cleaning water W filled in the cleaning tanks 15 to 19 described above.

  Thus, in FIG. 4, the heat-resistant separator S may be a film that is an intermediate product of the separator. The washing water W may be an aqueous solution containing an acid or a base.

  And the manufacturing method of a polyolefin separator is the intermediate | middle product of a long and porous separator, The shaping | molding process which shape | molds the elongate film which has polyolefin as a main component, The above-mentioned execution process is performed after this shaping | molding process. And each step included in the film cleaning method.

(Manufacturing method of laminated separator)
The manufacturing method of the heat-resistant separator S using the washing | cleaning method of the heat-resistant separator S which is a laminated separator is also contained in this invention. Here, the heat-resistant separator S is a laminated separator including the porous film 5 (base material) shown in FIG. 3 and the heat-resistant layer 4 (functional layer) laminated on the porous film 5. And this manufacturing method includes the formation process of shape | molding the long and porous heat-resistant separator S, and each process of the above-mentioned separator washing | cleaning method performed after the said formation process.

  In the “molding step”, in order to laminate the heat-resistant layer 4, an NMP (liquid material) containing an aramid resin (material) constituting the heat-resistant layer 4 is applied to the porous film 5. A coagulation step for coagulating the aramid resin.

  “Each step” includes a step of transporting the heat-resistant separator S in the longitudinal direction, and a step of cleaning the transported heat-resistant separator S by sequentially passing the water filled in the cleaning tanks 15 to 19. means.

  As described above, it is possible to manufacture a laminated separator with less NMP and less defects. The heat-resistant layer may be the above-described adhesive layer.

[Embodiment 2]
A second embodiment of the present invention will be described with reference to FIG. For convenience of explanation, members having the same functions as those described in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted. The same applies to the embodiments described later.

≪Configuration to remove washing water from heat-resistant separator≫
FIG. 5 is a cross-sectional view showing a peripheral configuration of the guide roll G used in the cleaning method of the present embodiment.

  As shown in FIG. 5, the cleaning device 6 further includes a guide roll G, a Teflon bar s, and a Teflon tube t. “Teflon” is a registered trademark.

  The guide roll G is fixed to the conveyance path of the heat-resistant separator S, does not rotate, and is disposed between the rollers 1 and m of the cleaning tank 15.

  The Teflon bar s extends in the longitudinal direction of the guide roll G and is provided on the surface of the guide roll G.

  The Teflon tube t is constrained so as to wrap the guide roll G and the Teflon bar s.

  The guide roll G may be arranged in the cleaning tanks 16 to 19. The cleaning device 6 may include a plurality of sets of guide rolls G, Teflon bars s, and Teflon tubes t.

≪Operation to remove cleaning water from heat-resistant separator≫
The cleaning method of this embodiment includes a step of removing the cleaning water W from the heat-resistant separator S between the upstream cleaning tank and the downstream cleaning tank, in addition to the steps included in the cleaning method of the first embodiment.

  When the heat-resistant separator S is pulled up from the water between the upstream washing tank and the downstream washing tank, part of the washing water W is brought into the downstream washing tank along the surface of the heat-resistant separator S due to surface tension. . Therefore, the cleaning water W brought into the downstream cleaning tank is scraped off from the heat-resistant separator S.

  The Teflon bar s provided on the surface of the fixed guide roll G forms a protrusion on the surface of the Teflon tube t. This protrusion is pressed against the heat-resistant separator S so as to lightly rub the heat-resistant separator S, and the cleaning water W is scraped off from the heat-resistant separator S.

  When the heat-resistant separator S was formed by coating an aramid heat-resistant layer on one surface of a polyethylene porous film, the heat-resistant separator S was formed on the surface of the Teflon tube t on the surface where the heat-resistant layer of the porous film was not coated. It is preferable to press the protrusion. Thereby, peeling of a heat-resistant layer can be suppressed.

<< Effects of this embodiment >>
The amount of cleaning water W brought from the upstream cleaning tank to the downstream cleaning tank is reduced. For this reason, the NMP concentration of the cleaning water W in the downstream cleaning tank can be surely made lower than the NMP concentration of the cleaning water W in the upstream cleaning tank. Therefore, it is possible to reliably remove NMP clogged in the holes of the heat-resistant separator S.

[Embodiment 3]
A third embodiment of the present invention will be described with reference to FIG.

≪Configuration to remove cleaning water from the transport roller that transports the heat-resistant separator≫
FIG. 6 is a cross-sectional view showing a peripheral configuration of the roller m used in the cleaning method of the present embodiment.

  As shown in FIG. 6, the cleaning device 6 further includes a scraping bar BL.

  The scraping bar BL is a blade that scrapes off the cleaning water W transported along the roller m by surface tension.

  A slight gap is provided between the roller m and the scraping bar BL. Thereby, it is possible to prevent the surface of the roller m from being scratched and the scraping bar BL from being worn.

≪Operation to remove cleaning water from the transport roller that transports the heat-resistant separator≫
The cleaning method of the present embodiment is a process of removing the cleaning water W from the roller m that transports the heat-resistant separator S between the upstream cleaning tank and the downstream cleaning tank, in addition to the steps included in the cleaning method of the first embodiment. including.

  When the heat-resistant separator S is conveyed, a part of the cleaning water W is brought into the downstream cleaning tank along the surface of the heat-resistant separator S due to surface tension. A part of the cleaning water brought into the downstream cleaning tank is conveyed along the roller m by the surface tension. Therefore, the cleaning water W transported along the roller m by the surface tension is scraped off from the roller m.

<< Effects of this embodiment >>
The amount of cleaning water W brought from the upstream cleaning tank to the downstream cleaning tank is reduced. For this reason, the NMP concentration of the cleaning water W in the downstream cleaning tank can be surely made lower than the NMP concentration of the cleaning water W in the upstream cleaning tank. Therefore, it is possible to reliably remove NMP clogged in the holes of the heat-resistant separator S.

[Modification 1]
The cleaning device 6 may include all of the guide roll G, the Teflon bar s, the Teflon tube t (FIG. 5), and the scraping bar BL (FIG. 6).

  The cleaning method of the present modification includes a process of removing the cleaning water W from the heat-resistant separator S between the upstream cleaning tank and the downstream cleaning tank, in addition to the processes included in the cleaning method of the first embodiment, And a step of removing the washing water W from the roller m carrying the heat-resistant separator S between the washing tank and the downstream washing tank.

  Thereby, the washing water W brought from the upstream washing tank to the downstream washing tank is further reduced. For this reason, the NMP concentration of the cleaning water W in the downstream cleaning tank can be more reliably lowered than the NMP concentration of the cleaning water W in the upstream cleaning tank. Therefore, NMP clogged in the hole of the heat-resistant separator S can be removed more reliably.

[Modification 2]
There may be one cleaning tank provided in the cleaning device 6. And this invention includes the following aspects.

The separator cleaning method according to aspect 1 of the present invention includes:
In a separator cleaning method for cleaning a long and porous battery separator,
Conveying the battery separator in its longitudinal direction;
Cleaning the battery separator being conveyed by passing it through a cleaning liquid filled in a cleaning tank; and
And a step of removing the cleaning liquid from the battery separator between a position where the battery separator is carried into the washing tank and a position where the battery separator is carried out from the washing tank.

  For example, in at least one of the cleaning tanks 15 to 19 shown in FIG. 4, the mode 1 includes, from the heat-resistant separator S (battery separator), the guide roll G and the Teflon bar s, as shown in FIG. 5. The washing water W is removed by the Teflon tube t. According to the aspect 1, it is possible to reduce the cleaning liquid brought into the other process from the cleaning process.

The separator cleaning method according to aspect 2 of the present invention includes:
In a separator cleaning method for cleaning a long and porous battery separator,
Conveying the battery separator in its longitudinal direction;
Cleaning the battery separator being conveyed by passing it through a cleaning liquid filled in a cleaning tank; and
And a step of removing the cleaning liquid from a transport roller that transports the battery separator between a position where the battery separator is carried into the washing tank and a position where the battery separator is carried out from the washing tank.

  For example, in at least one of the cleaning tanks 15 to 19 illustrated in FIG. 4, the aspect 2 is configured from a roller m (transport roller) that transports the heat-resistant separator S (battery separator) as illustrated in FIG. 6. The cleaning water W is removed by the scraping bar BL. According to the aspect 2, the cleaning liquid brought into the other process from the cleaning process can be reduced.

The separator cleaning method according to aspect 3 of the present invention includes:
In a separator cleaning method for cleaning a long and porous battery separator,
Conveying the battery separator in its longitudinal direction;
Cleaning the battery separator being conveyed by passing it through a cleaning liquid filled in a cleaning tank; and
A step of circulating the cleaning liquid to promote replacement of the cleaning liquid between the one surface side and the other surface side of the battery separator in the cleaning tank.

  Aspect 3 is, for example, a cleaning water W (cleaning liquid) between one surface side and the other surface side of the heat-resistant separator S (battery separator) in at least one of the cleaning tanks 15 to 19 shown in FIG. The cleaning water W is circulated to promote the replacement of the water. According to the aspect 3, the concentration of the removal target substance in the cleaning liquid in the cleaning tank can be made more uniform, and the efficient removal of the removal target substance can be promoted.

The separator cleaning method according to aspect 4 of the present invention includes:
In a separator cleaning method for cleaning a long and porous battery separator,
Conveying the battery separator in its longitudinal direction;
Cleaning the battery separator in transit by passing the battery separator through the cleaning liquid filled in the cleaning tank,
In the step of transporting the battery separator in the longitudinal direction, a driving force for transporting the battery separator to the battery separator between a position where the battery separator is carried into the washing tank and a position where the battery separator is carried out from the washing tank. Add

  For example, in the fourth aspect, in at least one of the cleaning tanks 15 to 19 shown in FIG. The driving force for conveying is applied to the heat-resistant separator S by the driving roller R. According to the aspect 4, the force applied to the battery separator is dispersed as compared with the case where the battery separator is pulled and conveyed only from the subsequent process of the cleaning process. As a result, generation | occurrence | production of malfunctions, such as a cutting | disconnection of the battery separator, can be suppressed.

  When a mechanism for applying driving force to the battery separator is disposed in the cleaning liquid, the position where the battery separator is carried into the washing tank may be a position where the battery separator is carried into the washing water of the washing tank. In addition, the position where the battery separator is carried out of the washing tank may be a position where the battery separator is carried out of the washing water of the washing tank.

The separator manufacturing method according to aspect 5 of the present invention includes:
A molding process for molding a long and porous battery separator;
Each step of the separator cleaning method according to any one of the above-described aspects 1 to 4, which is performed after the molding process.

  For example, after the heat-resistant separator S (battery separator) including the porous film 5 shown in FIG. 3 and the heat-resistant layer 4 laminated on the porous film 5 is molded, the aspect 5 is washed as shown in FIG. In at least one of the tanks 15 to 19, the heat-resistant separator S is washed. According to the aspect 5, it is possible to manufacture a battery separator having a higher air permeability than that of the conventional one, in which defects are suppressed.

The separator manufacturing method according to aspect 6 of the present invention is the above-described aspect 5,
The battery separator is a laminated separator including a base material and a functional layer laminated on the base material,
The molding step includes
In order to laminate the functional layer, an application step of applying a liquid substance containing a substance constituting the functional layer to the substrate;
A coagulation step for coagulating the substance after the application step;
May be included.

  Aspect 6 is, for example, an NMP (liquid material) containing an aramid resin (material) constituting heat-resistant layer 4 in order to laminate heat-resistant layer 4 (functional layer) on porous film 5 (base material) shown in FIG. ) Is applied to the porous film 5, the aramid resin is solidified, and the heat-resistant separator S is washed in at least one of the washing tanks 15 to 19 shown in FIG. According to the aspect 6, it is possible to manufacture a laminated separator having a higher air permeability than that of the conventional one in which defects are suppressed.

The separator cleaning method according to aspect 7 of the present invention includes:
In a film cleaning method for obtaining a long and porous battery separator,
A step of conveying a long film which is an intermediate product of the battery separator in the longitudinal direction;
Cleaning the film in transit by passing it through a cleaning liquid filled in a cleaning tank,
The film is mainly composed of polyolefin.

  Aspect 7 is, for example, an intermediate of a heat-resistant separator S (battery separator) formed by molding a polyolefin resin composition obtained by kneading polyolefin and an inorganic filler or a plasticizer into a film shape and stretching it. The product is washed in at least one of the washing tanks 15 to 19 shown in FIG. 4 to wash away the inorganic filler or plasticizer. According to the aspect 7, it is possible to obtain a polyolefin separator having a higher air permeability than that of the conventional one, in which defects are suppressed.

The separator cleaning method according to aspect 8 of the present invention includes:
A molding process for molding a long film which is an intermediate product of a long and porous battery separator;
Performed after the molding step,
A step of conveying a long film which is an intermediate product of the battery separator in the longitudinal direction;
A step of cleaning the film being conveyed by passing it through a cleaning liquid filled in a cleaning tank; and
including.

  In Aspect 8, for example, a polyolefin resin composition obtained by kneading polyolefin and an inorganic filler or a plasticizer is formed into a film shape and stretched to obtain an intermediate product of heat-resistant separator S (battery separator). Thereafter, the intermediate product is cleaned in at least one of the cleaning tanks 15 to 19 shown in FIG. According to the aspect 8, it is possible to manufacture a battery separator in which defects are suppressed and the air permeability is higher than the conventional one.

[Embodiment 4]
A fourth embodiment of the present invention will be described with reference to FIG.

≪Configuration to circulate cleaning water in the cleaning tank≫
FIGS. 7A and 7B are diagrams illustrating a configuration in which the cleaning water W is circulated in the cleaning tanks 15 and 16 of the present embodiment, where FIG. 7A is a side sectional view, FIG. 7B is a plan view, and FIG. Is a front sectional view, and (d) is a front sectional view showing a configuration different from (c). Note that the XYZ coordinate axes in FIG. 7 correspond to the XYZ coordinate axes in the drawings other than FIG. FIG. 7A corresponds to FIG. And in order to simplify drawing, in Fig.7 (a), only roller a * m is shown among roller am of FIG. Moreover, in FIG.7 (b), the rollers am and the heat-resistant separator S of FIG. 4 are not shown. 7C and 7D, the rollers a to m in FIG. 4 are not shown, and the heat-resistant separator S is indicated by a broken line.

  As shown in FIGS. 7A and 7B, the cleaning tank 15 includes discharge units 211 to 213 and a suction port 22. The discharge units 211 to 213 are provided so as to protrude from the Z-axis negative direction side of the inner wall of the cleaning tank 15 on the Y-axis negative direction side. A discharge port H is provided on the Z axis positive direction side (upper side) in the discharge units 211 to 213. The suction port 22 is provided on the Y axis positive direction side and the X axis negative direction side of the bottom surface of the cleaning tank 15. Note that the cleaning tank 16 also includes the discharge units 211 to 213 and the suction port 22, as in the cleaning tank 15.

≪Operation to circulate cleaning water in the cleaning tank≫
The discharge units 211 to 213 introduce the cleaning water W from the outside to the inside of the cleaning tank 15. The discharge port H discharges the introduced cleaning water W toward the Z axis positive direction. Then, as shown in FIG. 7C, the cleaning water W flows in the direction F near the inner wall of the cleaning tank 15 facing the end in the width direction of the heat resistant separator S on the Y axis negative direction side. Here, the “width direction” means a direction perpendicular to the longitudinal direction and the thickness direction of the heat-resistant separator S.

The suction port 22 sucks the cleaning water W from the inside of the cleaning tank 15 to the outside. Then, the cleaning water W sucked by the suction port 22 is discharged from the discharge portions 211 to 213 of the cleaning tank 15. Thereby, the cleaning water W circulates in the cleaning tank 15 as shown in the following (1) to (4).
(1) By being discharged, the cleaning water W flows in the vicinity of the inner wall of the cleaning tank 15 on the Y axis negative direction side from the Z axis negative direction side to the Z axis positive direction side.
(2) The cleaning water W flows on the water surface side (Z-axis positive direction side) of the cleaning tank 15 from the Y-axis negative direction side to the Y-axis positive direction side. That is, it flows from the inner wall on the Y axis negative direction side to the inner wall on the Y axis positive direction side in the upper part of the cleaning tank 15.
(3) By being sucked, the cleaning water W flows in the vicinity of the inner wall of the cleaning tank 15 on the Y axis positive direction side from the Z axis positive direction side to the Z axis negative direction side.
(4) The cleaning water W flows near the bottom surface of the cleaning tank 15 from the Y-axis positive direction side to the Y-axis negative direction side. That is, the vicinity of the bottom surface of the cleaning tank 15 flows from the inner wall on the Y axis positive direction side to the inner wall on the Y axis negative direction side.
The cleaning water W circulates in the cleaning tank 16 similarly to the cleaning tank 15.

<< Effects of this embodiment >>
In the film manufacturing method of this embodiment, the heat-resistant separator S is transported in the longitudinal direction so that the heat-resistant separator S passes through the water in the cleaning tank 15 ((a) in FIG. 7), and the cleaning water W is heat-resistant. This includes a step ((c) of FIG. 7) of introducing into the cleaning tank 15 from the inner wall of the cleaning tank 15 facing the end in the width direction of the separator S and discharging it upward.

  According to the above, the cleaning water W flows between the heat-resistant separator S and the inner wall of the cleaning tank 15 facing the end of the heat-resistant separator S in the width direction, and circulates in the cleaning tank 15. Therefore, the force applied to the heat resistant separator S when the flowing cleaning water W presses the surface of the heat resistant separator S is suppressed. Further, the cleaning water W on the surface of the heat-resistant separator S is updated, and the removal of the material to be removed of the heat-resistant separator S is promoted. Therefore, it is possible to manufacture the heat-resistant separator S in which the removal of the target substance to be removed is suppressed while suppressing the problems occurring in the heat-resistant separator S.

  In addition, the number of the discharge parts with which the washing tank 15 is provided is not limited to three. Further, the number of suction ports provided in the cleaning tank 15 is not limited to one. These numbers can be changed based on the dimensions of the cleaning tank 15, the cleaning capacity required for the cleaning tank 15, the flow rate of the cleaning water W, the transport path of the heat-resistant separator S, and the like. For example, by increasing the number of discharge units, the cleaning water W can flow in the vicinity of the inner wall of the cleaning tank 15 facing the end in the width direction of the heat-resistant separator S at a plurality of positions corresponding to the number of discharge units. it can. Thereby, more cleaning water W on the surface of the heat-resistant separator S is renewed, and the removal of the substance to be removed of the heat-resistant separator S is further promoted.

  Moreover, the discharge parts 211-213 and the suction port 22 may be provided in the washing tanks 17-19 shown by FIG. If at least one of the cleaning tanks 15 to 19 includes the discharge units 211 to 213, the heat-resistant separator in which the residue of the removal target substance is suppressed while suppressing the problems occurring in the heat-resistant separator S is suppressed. S can be manufactured.

(Discharge direction of cleaning water W)
As shown in (c) of FIG. 7, the direction F in which the cleaning water W is discharged from the discharge port H is a virtual straight line extending in the direction F starting from the discharge port H. It is set so as to pass between the inner wall of the cleaning tank 15 facing the end of the separator S in the width direction. Thereby, the washing water W can be replaced from the one surface side of the heat-resistant separator S to the other surface side.

  The direction F is set so that the heat-resistant separator S does not exist in water on a virtual straight line extending in the direction F starting from the discharge port H. Thereby, the washing water W can be switched from one side of the film to the other side while reliably suppressing the force applied to the heat-resistant separator S by the flowing washing water W pushing the surface of the heat-resistant separator S. .

  Moreover, the discharge port H is provided in the direction (Z-axis direction in this embodiment) perpendicular | vertical with respect to the rotating shaft of the rollers am in the discharge parts 211-213. The direction perpendicular to the rotation axis of the rollers a to m may be a direction in which the cleaning water W is discharged from the discharge port H along the inner wall of the cleaning tank 15. For example, the discharge port H may be provided on the direction side forming an angle included in an angle range of 60 ° or more and 90 ° or less with respect to the rotation axes of the rollers a to m in the discharge units 211 to 213.

  And at least the discharge part 212 is provided between the heat-resistant separator S conveyed below and the heat-resistant separator S conveyed upward in (a) of FIG. Accordingly, since the cleaning water W passes between the heat-resistant separator S transported downward and the heat-resistant separator S transported upward, renewal of the cleaning water W between the heat-resistant separators S can be promoted.

  Further, the discharge units 211A, 212A, and 213A shown in FIG. 7D also have the same effects as the discharge units 211 to 213 shown in FIG. 7C. That is, the cleaning water W enters the cleaning tank 15 from a position close to the inner wall on the Y axis negative direction side of the inner wall of the cleaning tank 15 facing the end portion in the width direction of the heat-resistant separator S on the bottom surface of the cleaning tank 15. It may be introduced and discharged upward.

(Bypass 23)
As shown in FIGS. 7B and 7C, between the cleaning tank 15 (first cleaning tank) and the cleaning tank 16 (second cleaning tank), the cleaning water W is supplied from the cleaning tank 16 to the cleaning tank. A detour 23 for moving to 15 is provided. The inlet through which the cleaning water W of the detour 23 flows is provided on the X-axis negative direction side and the Z-axis positive direction side of the inner wall of the cleaning tank 16 on the Y-axis positive direction side. The outlet from which the cleaning water W of the bypass 23 flows out is provided on the X-axis negative direction side and the Z-axis positive direction side of the inner wall of the cleaning tank 15 on the Y-axis positive direction side. Thus, a part of the cleaning water W does not obstruct the flow of the cleaning water W in the vicinity of the inner walls of the cleaning tanks 15 and 16 facing the end in the width direction of the heat-resistant separator S, and the cleaning tank 15 to the cleaning tank 15 Can move to. Further, as shown in FIG. 7B, the bypass 23 includes a filter 231. Thereby, it is possible to suppress the floating matter in the cleaning tank 16 from flowing into the cleaning tank 15.

  Note that a bypass 23 may also exist between two adjacent cleaning tanks 16 to 19. Further, a detour may be provided at all between two adjacent cleaning tanks 16 to 19. At this time, the cleaning water W flows in the direction D from the cleaning tank 19 to the cleaning tank 15 as shown in FIG. Then, the cleaning water W is newly supplied to the cleaning tank 19. Further, a part of the cleaning water W is discharged from the cleaning tank 15 to the outside.

(Modification of detour 23)
FIG. 8 is a view showing a modification of the bypass 23 shown in FIG. 7, wherein (a) is a front sectional view and (b) is a plan sectional view including the bypass 23 of (a). (C) is front sectional drawing which shows the modification different from (a).

  As shown in FIG. 8A, the bypass 23 may be provided near or on the bottom surfaces of the cleaning tanks 15 and 16. As shown in (b) of FIG. 8, the bypass 23 connects between the cleaning tank 15 and the cleaning tank 16 in the plane cross section including the bypass 23.

  As shown in FIG. 8C, the bypass 23 may be provided between the bottom surface of the cleaning tanks 15 and 16 and the water surface.

  As described above, the bypass 23 may be provided at any position that connects between the cleaning tank 15 and the cleaning tank 16. Further, the detour path 23 may connect the cleaning tank 15 and the cleaning tank 16 on the Y axis negative direction side.

(Pipe connecting between washing tanks)
FIG. 9 is a side cross-sectional view showing the configuration of the pipe 23a provided between the cleaning tank 16 and the cleaning tank 17 of the cleaning apparatus 6 shown in FIG. 4, wherein (a) is a cross-section including the pipe 23a. (B) shows a modification of (a).

  As shown in FIG. 9A, the pipe 23a extends in the X-axis direction so as to connect between the cleaning tank 16 and the cleaning tank 17, and is provided in the vicinity of the bottom surfaces of the cleaning tanks 16 and 17. Yes. The pipe 23a is a modification of the detour 23 having a function equivalent to that of the detour 23 shown in FIG.

  The inlet of the pipe 23 a is provided on the wall surface on the X axis negative direction side of the cleaning tank 17. The cleaning water W flows from the cleaning tank 17 into the pipe 23a through this inflow port. Further, the outlet of the pipe 23 a is provided on the wall surface on the X axis positive direction side of the cleaning tank 16. The washing water W flows out from the pipe 23a to the washing tank 16 through this outflow port.

  As shown in FIG. 9B, the pipe 23a may be provided between the bottom surface of the cleaning tanks 16 and 17 and the water surface. Further, the pipe 23 a may be provided in the vicinity of the water surface of the cleaning tanks 16 and 17.

  As described above, the pipe 23 a may be provided at any position that connects between the cleaning tank 16 and the cleaning tank 17.

(Inclination of the bottom of the washing tank)
As shown in FIG. 7A, the bottom surface of the cleaning tank 15 is inclined so that the direction D side is deeper than the opposite side. Thereby, at the time of maintenance, the washing water W can be discharged from the washing tank 15 without leaving the washing water W in the washing tank 15.

  The suction port 22 is provided on the direction D side of the bottom surface of the cleaning tank 15. And the direction D side of the bottom face of the washing tank 15 is inclined deeper than the opposite side. For this reason, the precipitate generated in the cleaning tank 15 gathers in the direction D side where the bottom surface of the cleaning tank 15 is lowered. Therefore, the sediment collects at the suction port 22.

  As described above, the cleaning water W sucked by the suction port 22 is discharged from the discharge portions 211 to 213 of the cleaning tank 15. At this time, the precipitate can be removed by filtering the washing water W before being discharged from the discharge portions 211 to 213.

  Further, as described above, the cleaning water W flows toward the direction D. For this reason, the bottom surface of the cleaning tank 15 has an X-axis negative direction side (position side where the heat-resistant separator S is carried into the cleaning tank 15), and an X-axis positive direction side (position side where the heat-resistant separator S is carried out from the washing tank 15). Is preferably lower.

(Other structural example 1 of a discharge part)
FIG. 10 is a diagram illustrating another configuration of the discharge units 211 to 213 of the cleaning tanks 15 and 16 illustrated in FIG. 7, and FIG. 10A illustrates the discharge units 211 to 213 in FIG. It is front sectional drawing which shows the structure of the discharge parts 211a-213a which changed the shape of 213. FIG. As shown in FIG. 10A, the portions inside the cleaning tank 15 of the discharge units 211 a to 213 a extend toward the Z-axis positive direction along the inner wall of the cleaning tank 15 on the Y-axis negative direction side. .

  As described above, the cleaning water W flows in the vicinity of the inner wall of the cleaning tank 15 on the Y axis negative direction side toward the Z axis positive direction side inside the discharge sections 211a to 213a immediately before being discharged from the discharge sections 211a to 213a. It is arranged. For this reason, the cleaning water W can reliably flow in the direction F near the inner wall of the cleaning tank 15 facing the end portion in the width direction of the heat-resistant separator S after being discharged from the discharge portions 211a to 213a.

(Other structural example 2 of a discharge part)
FIG. 10B is a plan view illustrating a configuration of the discharge unit 21b in which the supply sources of the cleaning water W of the discharge units 211a to 213a illustrated in FIG. Note that FIG. 10B corresponds to FIG. 7B. As shown in FIG. 10B, the inner end portion (discharge side) of the cleaning tank 15 of the discharge portion 21b is branched into three. The outer end (supply source) of the cleaning tank 15 of the discharge unit 21b is integrated. In addition, the shape of the discharge part 21b in the front cross section of the washing tank 15 is the same as that of the discharge parts 211a-213a shown by (a) of FIG.

  As described above, the cleaning water W is discharged from the three discharge ports H at a substantially uniform flow rate. Therefore, after the cleaning water W is discharged from the three discharge ports H, it flows in the direction F in the vicinity of the inner wall of the cleaning tank 15 facing the end portion in the width direction of the heat-resistant separator S at a uniform flow rate. Can do.

(Other structural example 3 of a discharge part)
FIG. 10C is a plan view showing a configuration of a discharge portion 21c provided with a discharge port Hc having a shape different from the discharge port H of the discharge portion 21b shown in FIG. As shown in FIG. 10C, the discharge portion 21c is provided with a discharge port Hc in which the three discharge ports H shown in FIG. 10B are integrated. The discharge port Hc extends in the X-axis direction, which is the direction in which the inner wall of the cleaning tank 15 extends. In addition, the shape of the discharge part 21c in the front cross section of the washing tank 15 is the same as that of the discharge parts 211a-213a shown by (a) of FIG.

  As described above, the cleaning water W is discharged from the discharge port Hc spreading in the X-axis direction at a substantially uniform flow rate. For this reason, the cleaning water W flows in the direction F in the vicinity of the inner wall of the cleaning tank 15 facing the end portion in the width direction of the heat-resistant separator S at a uniform flow rate in the X-axis direction after being discharged from the discharge port Hc. be able to. In addition, the discharge port Hc is not necessarily limited to the structure spread in the X-axis direction, and may be widened in the direction in which the inner wall extends.

(Film production equipment)
A film manufacturing apparatus including the cleaning tank 15, the rollers a to m (conveying device), and the discharge units 211 to 213 or the discharge units 211A to 213A is also included in the present invention. Similarly to the above-described film manufacturing method, this film manufacturing apparatus can manufacture the heat resistant separator S in which the residue of the substance to be removed is suppressed while suppressing the problems occurring in the heat resistant separator S.

[Embodiment 5]
A fifth embodiment of the present invention will be described with reference to FIG.

≪Other configurations for circulating cleaning water in the cleaning tank≫
FIG. 11 is a diagram showing a configuration for circulating the cleaning water W in the cleaning tanks 15 and 16 of the present embodiment, where (a) is a side sectional view, (b) is a plan view, and (c). Is a front sectional view. (A) to (c) in FIG. 11 correspond to (a) to (c) in FIG.

  As shown in FIGS. 11A and 11B, the cleaning tank 15 includes discharge portions 211d, 212d, and 213d and a suction port 22d. The discharge portions 211d, 212d, and 213d are provided so as to protrude from the Z-axis positive direction side of the inner wall of the cleaning tank 15 on the Y-axis negative direction side. Discharge ports H are provided on the Z-axis negative direction side (lower side) of the discharge portions 211d, 212d, and 213d. The suction port 22d is provided on the Z-axis positive direction side and the X-axis negative direction side in the inner wall of the cleaning tank 15 on the Y-axis positive direction side. Note that the cleaning tank 16 also includes the discharge portions 211d, 212d, and 213d and the suction port 22d, as in the cleaning tank 15. However, the suction port 22d of the cleaning tank 16 is provided on the Z-axis positive direction side and the X-axis positive direction side of the inner wall of the cleaning tank 16 on the Y-axis positive direction side.

≪Other operations for circulating cleaning water in the cleaning tank≫
The discharge units 211d, 212d, and 213d introduce the cleaning water W from the outside to the inside of the cleaning tank 15. The discharge port H discharges the introduced cleaning water W to the Z axis negative direction side. Then, as shown in FIG. 11C, the cleaning water W flows in the direction F around the inner wall of the cleaning tank 15 facing the end in the width direction of the heat resistant separator S on the Y axis negative direction side.

The suction port 22d sucks the cleaning water W from the inside of the cleaning tank 15 to the outside. The cleaning water W sucked by the suction port 22d is discharged from the discharge portions 211d, 212d, and 213d. Thereby, the cleaning water W circulates in the cleaning tank 15 as shown in the following (1d) to (4d).
(1d) By being discharged, the cleaning water W flows in the vicinity of the inner wall of the cleaning tank 15 on the Y axis negative direction side from the Z axis positive direction side to the Z axis negative direction side.
(2d) The cleaning water W flows near the bottom surface of the cleaning tank 15 from the Y-axis negative direction side to the Y-axis positive direction side. That is, the vicinity of the bottom surface of the cleaning tank 15 flows from the inner wall on the Y axis negative direction side to the inner wall on the Y axis positive direction side.
(3d) The cleaning water W is sucked and flows in the vicinity of the inner wall of the cleaning tank 15 on the Y axis positive direction side from the Z axis negative direction side to the Z axis positive direction side.
(4d) The cleaning water W flows on the water surface side (Z-axis positive direction side) of the cleaning tank 15 from the Y-axis positive direction side to the Y-axis negative direction side. That is, it flows from the inner wall on the Y axis positive direction side to the inner wall on the Y axis negative direction side in the upper part of the cleaning tank 15.
The circulation direction of the cleaning water W at this time is a direction obtained by reversing the circulation direction of the cleaning water W shown in FIG. 7C vertically (Z-axis direction). The cleaning water W circulates in the cleaning tank 16 similarly to the cleaning tank 15.

<< Effects of this embodiment >>
In the film manufacturing method of this embodiment, the heat-resistant separator S is transported in the longitudinal direction so that the heat-resistant separator S passes through the water in the cleaning tank 15 ((a) in FIG. 11), and the cleaning water W is heat-resistant. It includes a step of introducing into the cleaning tank 15 from the inner wall of the cleaning tank 15 facing the end in the width direction of the separator S and discharging it downward ((c) of FIG. 11).

  According to the above, the cleaning water W flows between the heat-resistant separator S and the inner wall of the cleaning tank 15 facing the end of the heat-resistant separator S in the width direction, and circulates in the cleaning tank 15. Therefore, the force applied to the heat resistant separator S when the flowing cleaning water W presses the surface of the heat resistant separator S is suppressed. Further, the cleaning water W on the surface of the heat-resistant separator S is updated, and the removal of the material to be removed of the heat-resistant separator S is promoted. Therefore, it is possible to manufacture the heat-resistant separator S in which the removal of the target substance to be removed is suppressed while suppressing the problems occurring in the heat-resistant separator S.

  In addition, the number of the discharge parts with which the washing tank 15 is provided is not limited to three. Further, the number of suction ports provided in the cleaning tank 15 is not limited to one. These numbers can be changed based on the dimensions of the cleaning tank 15, the cleaning ability required for the cleaning tank 15, the flow rate of the cleaning water W, the transport path of the heat-resistant separator S, and the like.

  Moreover, the discharge parts 211d, 212d, 213d and the suction port 22d may be provided in the cleaning tanks 17 to 19 shown in FIG. If at least one of the cleaning tanks 15 to 19 is provided with the discharge portions 211d, 212d, and 213d, it is possible to suppress the defects that occur in the heat-resistant separator S and to suppress the residue to be removed. A heat-resistant separator S can be manufactured.

(Bypass 23d)
In the present embodiment, a bypass 23 d is connected to the cleaning tank 15 and the cleaning tank 16. The detour 23 d includes a filter 231, similar to the detour 23. However, unlike the bypass 23, the bypass 23d connects the cleaning tank 15 and the cleaning tank 16 on the Y-axis negative direction side.

  The detour path 23d may be provided at any position that connects between the cleaning tank 15 and the cleaning tank 16, similarly to the detour path 23 shown in FIG. Further, the bypass circuit 23d may connect the cleaning tank 15 and the cleaning tank 16 on the Y axis positive direction side.

(Film production equipment)
A film manufacturing apparatus including the cleaning tank 15, the rollers a to m (conveying device), and the discharge units 211d to 213d is also included in the present invention. Similarly to the above-described film manufacturing method, this film manufacturing apparatus can manufacture the heat resistant separator S in which the residue of the substance to be removed is suppressed while suppressing the problems occurring in the heat resistant separator S.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention can also be used for manufacturing films other than separators.

4 Heat-resistant layer (functional layer)
5 Porous film (base material)
6 Cleaning device 15-19 Cleaning tank (liquid tank)
21b, 21c, 211-213, 211A to 213A, 211a to 213a, 211d to 213d Discharge part 22, 22d Suction port 23, 23d Detour 23a Pipe
BL scraping bar
G Guide roll H / Hc outlet
R drive roller
S heat-resistant separator (battery separator, laminated separator, film)
W Wash water (liquid)
a to m rollers (conveyance rollers)
p ・ q Auxiliary roller
s Teflon bar
t Teflon tube

Claims (18)

Transporting the film in the longitudinal direction so that the film passes through the liquid in the liquid tank;
Introducing the liquid into the liquid tank from the inner wall of the liquid tank facing the end in the width direction of the film, and discharging the liquid upward or downward;
The film manufacturing method characterized by including.   The discharging step is characterized in that the liquid is introduced into the liquid tank by a discharge portion protruding from the inner wall and discharged from a discharge port provided on the upper side or the lower side of the discharge portion. 2. The method for producing a film according to 1.   In the discharging step, a direction in which the liquid is discharged from the discharge port is set so that a straight line extending in the discharge direction passes between the film and the inner wall in the liquid. The film manufacturing method according to claim 2, wherein   4. The film manufacturing method according to claim 3, wherein in the discharging step, the discharging direction is set so that the film does not exist in the liquid on the straight line. In the transporting step, the film is transported by a roller,
5. The discharge step according to claim 2, wherein the discharge port is provided on a direction side perpendicular to a rotation axis of the roller in the discharge unit. Film manufacturing method.   6. The film manufacturing method according to claim 2, wherein, in the discharging step, the discharge portion extends along the inner wall.   7. The film manufacturing method according to claim 2, wherein in the discharging step, the discharge port extends in a direction in which the inner wall extends.   In the said discharge process, the said liquid is supplied in the said liquid tank by the said some discharge part, The film manufacturing method as described in any one of Claim 2 to 7 characterized by the above-mentioned.   The film manufacturing method according to claim 8, wherein in the discharging step, the liquid supply sources of the plurality of the discharge units are integrated. A step of sucking the liquid from a position closer to the inner wall of the liquid tank facing the inner wall of the liquid tank than the inner wall of the liquid tank to introduce the liquid, on the bottom surface of the liquid tank;
The film manufacturing method according to claim 1, wherein in the discharging step, the liquid is discharged upward. A step of sucking the liquid from a position closer to the liquid level of the liquid than the bottom surface of the liquid tank on the inner wall of the liquid tank facing the inner wall into which the liquid is introduced;
The method for producing a film according to claim 1, wherein in the discharging step, the liquid is discharged downward.   The film manufacturing method according to claim 1, wherein a bottom surface of the liquid tank is inclined. The bottom surface of the liquid tank is inclined,
The film manufacturing method according to claim 1, further comprising a step of sucking the liquid from a lower side of the bottom surface.   The bottom surface is characterized in that a position side where the film is carried into the liquid tank in the transporting step is lower than a position side where the film is unloaded from the liquid tank in the transporting step. 14. The film production method according to 12 or 13. In the transporting step, the film is transported in the longitudinal direction so that the film passes through the liquids of the first and second liquid tanks,
In the discharging step,
The liquid is introduced into the first liquid tank from the inner wall of the first liquid tank facing the end in the width direction of the film, and discharged upward or downward.
The liquid is introduced into the second liquid tank from the inner wall of the second liquid tank facing the end of the film in the width direction, and discharged upward or downward.
The film manufacturing method according to claim 1, further comprising a step of moving the liquid from the second liquid tank to the first liquid tank. Transporting the film in the longitudinal direction so that the film passes through the liquid in the liquid tank;
Introducing the liquid into the liquid tank from a position closer to one of the two inner walls of the liquid tank facing the end in the width direction of the film on the bottom surface of the liquid tank, and discharging the liquid upward; When,
The film manufacturing method characterized by including. A liquid tank;
A transport device for transporting the film in the longitudinal direction so that the film passes through the liquid in the liquid tank;
A discharge section for introducing the liquid into the liquid tank from the inner wall of the liquid tank facing the end in the width direction of the film, and discharging the liquid upward or downward;
A film manufacturing apparatus comprising: A liquid tank;
A transport device for transporting the film in the longitudinal direction so that the film passes through the liquid in the liquid tank;
The liquid is introduced into the liquid tank from a position closer to one of the two inner walls of the liquid tank facing the widthwise end of the film on the bottom surface of the liquid tank, and discharged upward or downward. A discharge part to be
A film manufacturing apparatus comprising:

Images