JP2016219100A - Gravure coating machine for heat resistant material coating on separator for lithium ion battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a member film such as a separator highly functional in order to improve the characteristics of applications of lithium ion batteries.SOLUTION: In a gravure coating machine for coating a heat resistant material on the separator for a lithium ion battery according to the present invention, an angle θ at which a line (7) connecting the center (1A, 1B) of a gravure roll (1) and a nip roll (2) intersects the horizontal line (8) passing through the center (1A) of the gravure roll (1) can be changed at -60°≤θ≤60°, and by passing a base material (6) twice or more into a drying furnace (11), it is possible to uniformly apply an organic or inorganic various kinds of heat resistant at once without winding up to both surfaces of base material (6) having a thickness of 50 μm or less, in order to improve productivity, so that a high-quality and inexpensive heat-resistant separator film and the like can be produced.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a gravure coating machine for applying a heat-resistant material to a separator for a lithium ion battery, and more particularly to a novel improvement for obtaining a coating film having high reliability and safety.

  In general, a microporous membrane made of polyolefin is used as a separator for a secondary battery. In this method, polyethylene (hereinafter referred to as PE) or polypropylene (hereinafter referred to as PP) is used as a raw material, and the production methods put into practical use are roughly classified into a wet method and a dry method. In the former, PE is melt-kneaded in a extruder together with a compatibilizing agent such as paraffin, and the part occupied by the compatibilizing agent is methylene chloride in the sea-island structure observed in the phase separation phenomenon that occurs in the cooling process during sheet forming. It is a method of obtaining microporosity by removing with a degreasing solvent. On the other hand, the lamellar hole opening method and the β crystal method are known as the dry method. For example, in the case of the lamellar hole opening method, after PP is melt-kneaded with an extruder, the extrusion speed is increased when the sheet is pulled out from a T die with a roll. This is a method of forming micropores by increasing the rotation speed (draw ratio) of the roll with respect to the crystal, crystallizing by raising the orientation of the PP molecules, and then stretching under the optimum conditions to create cracks between the crystals. . However, although the separator manufactured with these raw materials depends on the molecular weight and the degree of crystallinity, it heat shrinks when it exceeds 100 ° C. Therefore, in general, when an electrolyte used in a non-aqueous secondary battery such as a lithium ion battery (hereinafter referred to as LIB) vaporizes, decomposes, or generates heat in some state, the separator is thermally contracted and the film is broken. (Hereinafter referred to as short-circuit) causes a short-circuit between the positive and negative electrodes, so that the so-called thermal runaway from combustion to explosion cannot be stopped, and there is a safety problem at present.

  The separator for a non-aqueous secondary battery described above is required to safely end the battery by maintaining insulation without causing the separator to short-circuit even when the battery temperature rises. In order to satisfy these requirements, various methods such as coating of a heat-resistant layer and a multilayer structure have been attempted. However, since the manufacturing method is complicated, thinning is difficult, and the cost is increased, it is an obstacle to the application and popularization for electric vehicles and stationary applications.

  In general, as a measure for improving the heat resistance of a separator using a polyolefin-based material, a technique of coating an organic or inorganic material on the surface is known.

  As the above-mentioned inorganic material, heat resistance is improved by applying a slurry-like liquid in which ceramic fine particles such as alumina and silica are mixed with an organic material for adhesion to the separator surface (Patent Documents). 1, Patent Document 2).

  In addition, as an organic material, polyamide, polyimide, or the like is used alone or mixed with an inorganic material while serving as a binder, and is applied onto a separator to improve heat resistance. (Patent Literature 3, Patent Literature 4).

  These coating liquids are applied to the separator using a so-called coating machine (Patent Document 5), and a slit die coating machine, a gravure coating machine, and the like are generally used.

  In addition, when it is desired to coat both surfaces, a material having a certain degree of strength such as a LIB (lithium ion battery, hereinafter referred to as LIB) electrode or the like (Patent Document 6) corresponds to the floating type.

Japanese Patent Application No. 2011-256862 Japanese Patent Application No. 2013-79308 Japanese Patent Application No. 2008-275533 Japanese Patent Application No. 2009-517884 Japanese Patent Application No. 2009-163266 Japanese Patent Application No. 2010-197462

  Since the conventional coating method is configured as described above, the following problems exist. For example, in the case of Patent Document 5 described above, these coating liquids are applied to the separator using a so-called coater, and a slit die coater, a gravure coater, or the like is generally used. However, there are various kinds of organic binders and inorganic fine particles, and the viscosity of the liquids is different. Therefore, it is difficult to apply thin and uniform thickness on the separator at high speed. .

  In the case of Patent Document 5, if it is desired to coat both surfaces, a material having a certain level of strength, such as a LIB electrode, can be handled by a floating type. However, in the case of a separator, since it is thin and lacks strength, It is difficult to apply to both sides, and it is generally applied one side at a time. In the case of coating on both sides, after coating on the front side and winding up once, then the back side of the batch was applied, resulting in poor productivity and increased costs.

  The present invention has been made to solve the above-described problems. In particular, in order to improve the safety of a secondary battery such as LIB, various kinds of organic or permanent heat-resistant agents are applied onto the separator. An object of the present invention is to obtain a coating machine that can easily provide a high-quality and inexpensive heat-resistant separator by coating both surfaces at once without winding both surfaces in order to increase productivity uniformly.

  A gravure coating machine for applying a heat resistant material to a separator for a lithium ion battery according to the present invention is a lithium ion having a gravure roll and a nip roll for applying a heat resistant organic or inorganic material to a substrate via a gravure head. In the gravure coating machine for heat-resistant material application to the battery separator, the line connecting the gravure roll and the center of the nip roll with respect to the position of the nip roll with respect to the gravure roll is a horizontal line passing through the center of the gravure roll; The intersecting angle θ can be changed in a range of −60 ° ≦ θ ≦ 60 °, and the ratio of the diameter D of the gravure roll and the diameter d of the nipple is 1 ≦ D / d ≦ 5. In order to change the drying state of the base material, the base material is placed in a drying furnace two or more times. It is configured to pass back and change the dry state of the base material by changing the residence time, and has two gravure heads and is configured to coat both sides of the base material. The drying furnace has a structure in which slits for ejecting hot air are arranged at two or more locations in the drying furnace, and the drying furnace is partitioned in one or two stages. The winding speed of the material is 5 m / min to 200 m / min, and the same coating is achieved by changing the gravure roll and nip roll angles of the two gravure heads at the inlet and outlet of the drying furnace. Even when the coating liquid is applied at the same speed, the thickness and adhesiveness can be changed depending on the state of the coating liquid and the substrate, and the inorganic fine particle material in the coating liquid is 30% or more. Of inorganic fine particles An average size is 10 μm or more and 100 μm or less, and two gravure heads are used by using a gravure coating machine for applying a heat resistant material to a lithium ion battery separator according to claim 1 or 2. The gravure head is disposed so as to face each other, and the gravure head has the function of the nip roll, and the drying furnace does not have a roll for supporting the substrate, and the substrate is floated in the drying furnace. It is the structure which dries both surfaces of a material.

Since the gravure coating machine for coating a heat-resistant material on a lithium ion battery separator according to the present invention is configured as described above, the following effects can be obtained.
In other words, it is possible to apply various types and solid-liquids to a uniform thickness in an optimal state according to physical properties by simple means, and when used as a separator such as LIB, a highly safe and reliable coating film is obtained. It is done.
In addition, since the same apparatus can be used to coat both front and back surfaces without winding up the film, productivity can be improved and manufacturing costs can be greatly reduced.

It is the block diagram which showed the state of the base material, and the state of the meniscus when the line | wire which tied the center part of the nip roll and the gravure roll in the coating machine of this invention was made parallel to X-ray | X_line. It is the block diagram which showed the state which pressed down the nip roll in the coating machine of this invention to the gravure roll side at the upper part of the gravure roll, and pressed down to the X direction and raised the adhesive pressure to the base material of a coating liquid. In the coating machine of this invention, it is a block diagram at the time of making a base material bend | fold back in a furnace and let the inside of a furnace pass again after coating a heat-resistant material to one side of a base material. It is a block diagram which shows an example of the double-sided coating machine in the coating machine of this invention. It is a block diagram which shows the example which divided each drying furnace of the double-sided coating machine in this invention into the upper and lower two steps. It is a block diagram which shows the example of a floating drying furnace with the double-sided coating machine in this invention. It is the example which showed the coating thickness distribution of the base-material width direction of Example 1 of this invention. It is the example which showed the coating thickness distribution of the base-material width direction of Example 4. FIG. It is the example which showed the coating thickness distribution of the base-material width direction of the comparative example 2. It is a safety | security evaluation test result of the heat resistant separator and uncoated sample in the Example by this invention.

  The gravure coating machine for applying heat-resistant materials to lithium ion battery separators according to the present invention enables optimum coating of various organic and inorganic heat-resistant materials according to their physical properties. It is possible to realize a configuration in which coating can be performed at a time with an apparatus.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a gravure coating machine for applying a heat resistant material to a lithium ion battery separator according to the present invention will be described with reference to the drawings.
In addition, about implementation, it carried out using the commercially available separator (CS-TECH company_made: Selion P1610H) using the gravure coating machine (made by Sakai machine industry Co., Ltd.) with the specification of Table 1 as a base material. The outline of the base material is shown in Table 2.

  In general, the configuration of the gravure head 3 of the gravure coating machine is as shown in FIG. 1, and the line 7 connecting the center of the gravure roll 1 and the centers 1A and 2A of the nip roll 2 is horizontal to the X axis. Is arranged. In this state, the gravure roll 1 is rotated clockwise while pulling the substrate 6 upward. At this time, when the rotation speed and the pulling speed of the base material 6 are optimized, the meniscus 5 is formed in a state in which the coating liquid 4 can be successfully applied to the base material 6. However, since the adhesion state to the base material 6 differs depending on the physical properties of the coating liquid 4 and the state of the coating machine 10, in the case of adhesion of inorganic fine particles, they are easily peeled off or the surface becomes rough. To do. Usually, in order to control this state, the coating state can be controlled to some extent by changing the ratio of the speed of the gravure roll 1 and the speed of the substrate 6. However, the state of the meniscus 5 is constant, and in the case of a coating liquid containing fine particles, it is difficult to improve surface adhesion.

  On the other hand, as shown in FIG. 2, by moving the contact point of the nip roll 2 above the gravure roll 1 and tilting the tangent line in the range of −60 ° to 60 ° with respect to the X axis, The pressure in the X-axis direction toward the gravure roll 1 side can be increased or decreased, and the effect of increasing adhesion by pressing the fine particles on the substrate 6 onto the gravure roll 1 can be provided. This pressure is also effective by increasing the force F for pulling up the substrate 6. In addition, since it is thought that the force which pulls up the base material 6 is proportional to winding-up speed, it is thought that a surface state can be improved in the state which raised productivity, and is effective.

In the present invention, the relationship between the position between the gravure roll 1 and the nip roll 2 and the adhesive pressure Fx of the coating liquid 4 to the sheet surface of the substrate 6 is based on the positional relationship in FIG. If the angle with the axis is θ and the tension for pulling up the film in the y-axis direction is F, it is expressed as follows and is proportional to the winding speed.
Fx = F'sinθ = (ρdlvt · dv / dt) sinθ
(F ′: winding tension, d: film thickness, 1: film width, v: winding speed, t: unit time, ρ: density, dl / dt: length per unit time), dv / dt: winding When the take-off acceleration, θ> 0, the adhesion pressure increases as described above.

  At this time, the drying state in the drying furnace 11 of FIG. 3 changes depending on the coating state of the heat-resistant material on the substrate 6. When it is applied thickly or when the density is increased by pressure bonding, the dry state becomes worse. However, if the drying furnace 11 is extended, the space occupied by the apparatus becomes wide and the cost increases.

  In the present invention, as shown in FIG. 3, the coated film is folded back at the outlet 12 in the drying furnace so that the residence time in the drying furnace 11 can be earned even when the drying state is bad, and again in the drying furnace 11. By making it a system that can pass through, various heat-resistant materials can be applied.

  In the present invention, the second gravure head 3A is brought into a dry state before entering the drying furnace 11 again by turning back from the outlet 12 of the drying furnace 11 and passing through the drying furnace 11 again. By arranging them accordingly, it becomes a structure that can be continuously applied continuously on both sides.

  Depending on the dry state, as shown in FIG. 4, the operation of the second gravure head 3A can be stopped and the dry state can be raised. In addition, since the thickness can be controlled by adjusting the position of the nip roll 2 even though the structure is the same, after coating one surface (referred to as a table) thickly in the first unit, the first unit in the second unit If the opposite surface (back) is coated thinner, the surface can pass through the drying furnace twice, so that both the front and back surfaces can be sufficiently dried.

The configuration of FIG. 5 is a modification of FIG. 4, in which the substrate 6 is dried in a two-stage type in the drying furnace 11, and another second gravure head is formed on the opposite surface of the coated surface coated on the substrate 6. In this configuration, both sides are coated with 3A. FIG. 6 shows a configuration in which both surfaces of the base material 6 are dried in a state of being floated in the drying furnace 11 without having a roll for supporting the base material 6 in the drying furnace 11.
In the configuration of FIG. 4, a coating of two layers (organic and inorganic layers) can be formed on one surface of the substrate 6, and the organic substance is preferably amyrad, PVdf, etc., and the inorganic substance is ceramic. Etc. can be used.

  The film as the substrate 6 used in the present invention is preferably a film having a thickness of 5 μm to 50 μm and a width of about 200 mm to 3000 mm. Moreover, when the film to be used is a microporous film, it is preferable to use a film having a microporous pore distribution of about 10 nm to 10 μm and an average pore distribution of several hundred nm. In addition, the tensile strength (MD) / width (TD) or one of them is about 100 MPa or more, the Gurley value is several hundred s / 100 cc air, the puncture strength is 300 gf or more, and the porosity is 40% or more. It is preferable to use it.

  It is preferable that the microporous film as the substrate 6 is applied under a condition that the winding speed is 5 m / min to 150 m / min, and the furnace temperature is 60 ° C. or higher and 130 ° C. or lower. The film is preferably in a state where a tension of about several Newtons is applied.

  The coating liquid 4 used in the present invention imparts heat resistance to the film. It preferably contains an inorganic substance such as alumina, silica, aluminum hydroxide, boehmite and the like having a particle size of several tens to several hundreds of μm and a solid content ratio of 40 wt% or less. Examples of the binder include side chain or cyclic polymer resins, acrylic resins, and compounds thereof. Furthermore, either aqueous or organic dispersion can be selected depending on the purpose.

  Next, in the present invention, the coating is performed by the gravure coating machine 10, and the gravure roll 1 is engraved in a spiral grooved shape in order to transport the liquid uniformly to the entire roll surface. The groove width and depth of this engraving are not limited. In addition, the engraving pattern is not limited to a spiral shape, so that the coating liquid can be transported optimally.

  Moreover, although the gravure roll 1 needs to contact the nip roll 2, an offset method may be used. However, the nip roll 2 requires a certain degree of surface hardness, and the flexo method is not suitable.

  Next, in order to transport the coating liquid 4 to the gravure roll 1, the chamber in which the coating liquid 4 is stored comes into contact with the gravure roll 1, but its shape and contact state are also limited. is not. Furthermore, since the liquid storage chamber serves as a buffer, the pump for transporting the coating liquid 4 does not need to use a special pump that suppresses pulsation. In some cases, a pipe that connects the container and the storage chamber at the top of the device, and a cock placed between them, and by opening the cock, a certain amount of coating liquid drops into the storage chamber due to gravity can be used for transportation. Does not require the pump itself.

  The configuration of the gravure coating machine 10 is roughly divided into a film feeding unit 9, a coating unit 20, a drying furnace 11 having a hot air slit 8, and a winding unit 13. However, tension control and winding are performed. A device for controlling the state is attached as necessary. The use of other commonly used devices is not limited. The rolls 1 and 2 may be supported only on one side or on both ends, and are appropriately selected depending on the width of the equipment film.

  In the present invention, the microporous film serving as the substrate 6 is not only a single layer but also a resin composition having a different composition or a multilayer structure in which other microporous films are laminated. Also good.

Examples Hereinafter, examples will be shown to describe the present invention more specifically, but the present invention is not limited to these examples.
In addition, the physical property of the microporous film shown in an Example and a comparative example was measured with the following method.

(1) Mechanical properties were measured using an autograph (manufactured by Shimadzu Corporation).
(2) The puncture strength was measured by using an automatic puncture strength meter (manufactured by Kato Tech Co., Ltd .: KES-FB3-AUTO) to measure the maximum load when the needle penetrated. In addition, 10 points | pieces were measured with the same sheet | seat, and the average value was computed.
(3) The Gurley value was measured using a Gurley type automatic measuring machine (manufactured by TESTING MACHINES INC) by cutting out the prepared sheet into a 50 mm × 50 mm square. In this measurement, the time required for 100 cc of air defined by JISP8177 to pass through the sheet was taken as the Gurley value.
(4) The porosity and film thickness were cut into 50 × 50 mm square samples, 10 points on each part of the sheet were measured using a micrometer, and the average value was taken as the film thickness. The porosity was calculated from the actual weight of the sheet and the theoretical weight calculated from the density and volume.
(5) For FE-SEM observation, surface observation was performed using a sheet FE-SEM (SUPRA55VP manufactured by Carl Zeiss Co., Ltd.) on which platinum deposition with a thickness of 0.3 nm was performed using a vacuum deposition apparatus (E-1045 manufactured by Hitachi High-Tech). Went.
(6) Surface roughness was observed using a scanning probe microscope (SPM-9700, manufactured by Shimadzu Corporation).
(7) Battery evaluation is positive and negative electrode: LI (Ni, Mn, Co) 02 / Graphite system, electrolyte: 1M LiPF6 / EC: DEC = 1: 1 vol, + VC 3Ah class laminated laminate type battery, manufactured with nail diameter A nail penetration test was performed in φ3 mm, speed: 1 mm / sec, thermostatic chamber 25 ° C., and air atmosphere, and the nail temperature and ambient temperature were measured over time.

Example 1
Using the gravure coating machine 10 shown in Table 1, the base film shown in Table 2 is coated with an average particle size of alumina of 0.8 to 1.2 μm, a solid content ratio of 40 wt%, and a solvent based on water. The coating solution was gravure coated only on one side so that the coating thickness after drying was 2 μm. At this time, the film speed was 7 to 10 m / min, and the conditions were set so that the ratio of the gravure roll speed to the film speed was 110%. At this time, the temperature in the drying furnace was set to 85 ° C. with the angle between the line connecting the centers of the gravure roll and the nip roll and the X axis being about 0 to 10 °. The unwinding tension and winding tension were 2.5 kg and 3.5 kg, respectively. FIG. 8 shows the thickness distribution in the width direction of Example 1.

Example 2
By the method of Example 1, gravure coating was performed on both surfaces of the substrate 6. The rest is the same as in the first embodiment.
Example 3
In the method of Example 1, the angle between the line 7 connecting the gravure roll 1 and the centers 1A and 2A of the nip roll 2 and the X axis was set to 10 to 20 °. The film speed was 5 m / min. At this time, the temperature in the drying furnace 11 was set to 70 ° C. The rest is the same as in the first embodiment.
Example 4
The film speed was set to 10 m / min by the method of Example 3. The rest is the same as in Example 3.
Example 5
The temperature in the drying furnace 11 was set to 85 ° C. by the method of Example 4. The rest is the same as in the first embodiment.
Example 6
In the method of Example 5, the temperature in the drying furnace 11 was set to 95 ° C. The rest is the same as in the first embodiment.

Comparative Example 1
The base material 6 is an example at the time of coating with the apparatus of another company using P1610H. Different coating liquids are used, and the coating conditions are also different.
Comparative Example 2
This is an example in which the head is a slit die system under the conditions of the first embodiment. FIG. 10 shows the thickness distribution in the width direction of Comparative Example 2.

Results Comparison Tables 3 and 4 show the characteristics of separator sheets coated with a heat-resistant material under the conditions of Examples 1 to 6 and Comparative Examples 1 and 2. The SEM photograph to Comparative Example 1 have a magnification of 100,000,000, and a portion where the state of adhesion of alumina is partially poor is seen at the center. Except for Comparative Example 1, almost the same tendency is seen in the overview.

  Next, the Gurley value, the porosity, the puncture strength, and the thermal shrinkage rate at 100 ° C., 120 ° C., 140 ° C., and 160 ° C. in each example shown in Table 3 are compared. Except for Example 2 and Comparative Examples 1 and 2, the thickness is about 16.5 to 17 μm, and since it is considered that the thickness of the base material varies, all samples are coated to a target thickness of 2 μm on one side. Has been. In that case, Example 1 is somewhat larger, but generally the Gurley value is about 210 sec / 100 cc, so the resistance of gas passage by surface coating is larger than that of the base material. Further, the corresponding porosity is about 42%, and there is not much change. The puncture strength tends to decrease somewhat at about 320 gf. The thermal shrinkage was about 5% at 120 ° C. MD, but after application, the shrinkage was 2% or less. In particular, Examples 3 and 4 showed no shrinkage at 0%.

  Although the Gurley value of Comparative Example 1 in Table 4 described above is close to that of the base material, it is estimated that the adhesiveness to the base material is poor because the heat resistance at 140 ° C. or higher is poor. The adhesiveness to the substrate is not so different at about 120 ° C., but it can be seen that a large difference in heat resistance occurs at higher temperatures.

  Looking at the separator characteristics of Comparative Example 4 in Table 4 above, the thickness of the Comparative Example is thicker than the others. The coating thickness is considered to be about 7 μm, calculated from the substrate thickness shown in Table 1, but it can be seen that under the present conditions, the slit die could not apply alumina to the desired thickness. Other physical properties are considered to be not significantly different from the examples using the gravure coater.

  The thickness distribution of the base material width direction of Example 1, Example 4, and Comparative Example 2 was shown in FIGS. In FIG. 8, the coating is almost uniformly applied to a thickness of 2 μm, but in FIG. 9, the coating thickness is about 0.5 μm. On the other hand, FIG. 10 is applied to a thickness of 7 μm to 9 μm despite a coating of 2 μm, and there is a difference of about 2 μm in the width direction.

In order to compare the coating states in more detail, Table 5 shows photographs of scanning probe microscopes of Examples 1, 3, and 4 and Comparative Example 1. The fact that the height image is not so different is the same as in the SEM photograph, but in Example 2 where the coating pressure was increased by changing the conditions from Example 1 and shifting the positions of the gravure roll and nip roll. The surface roughness is clearly improved. Furthermore, when the coating speed was increased to the same speed as in Example 1, the pressing force against the gravure roll of the base material was increased so that the three-dimensional image and the surface unevenness were improved, and the roughness was 25%. It can be seen that the degree is improved.
On the other hand, Comparative Example 1 was in a state with poor heat resistance, but the roughness was also rough as compared with the Examples, and the adhesion to the substrate was poor and the coating state was not good.

  FIG. 10 shows the results of the nail pointing battery evaluation test in the case where a laminated battery was prepared using the separator of Example 1. The figure on the left is the case of only the base material, but both the nail temperature and the ambient temperature rise greatly from around 40 seconds immediately after the nail is stabbed, and the surface temperature of the nail particularly exceeds 250 ° C. In this state, the positive and negative electrodes are short-circuited due to thermal contraction, flammable gas is generated due to the evaporation and decomposition of the electrolyte, and the combustion and explosion runaway phenomenon occurs because the ignition point is reached. On the other hand, in the right-hand coated sample, the nail temperature only rises to about 120 ° C. In this case, the heat shrinkage rate is 2% or less and no short circuit occurs, so it is considered safe.

The gist of the gravure coating machine for heat-resistant material coating on the lithium ion battery separator according to the present invention is as follows.
That is, the substrate according to the present invention uses a microporous film made of PE or PP used as a raw material for a secondary battery such as LIB. When various heat-resistant materials are applied to the base material 6 using the gravure coating machine 10, the contact point between the gravure roll 1 and the nip roll 2 that holds the base material 6 is viewed from the side, and can be moved on the circumference of the gravure roll 1. To. Specifically, the angle between the line 7 connecting the centers 1A and 2A and the line (X axis) extending horizontally from the center 1A of the gravure roll 1 can be adjusted in a range of −60 ° to 60 °. The state of the meniscus that changes depending on the type of the coating liquid 4 by adjusting the holding of the substrate 6 to the gravure roll 1 and pressing the substrate 6 sheet into the gravure roll 1 with a force corresponding to the angle. The coating pressure is controlled, and the substrate 6 is coated in an optimum state for the target physical properties.
Further, by having two gravure heads 3 having this adjustment function, it is possible to provide a double-side coating machine capable of continuously coating a heat-resistant material on both sides without winding up once.

More specifically, it is as follows.
That is, in a gravure coating machine for applying a heat resistant material to a lithium ion battery separator having a gravure roll 1 and a nip roll 2 for applying a heat resistant organic or inorganic material to a substrate 6 via a gravure head 3. The angle θ at which the line 7 connecting the position of the nip roll 2 with respect to the gravure roll 1 between the center 1A, 1B of the gravure roll 1 and the nip roll 2 intersects the horizontal line 8 passing through the center 1A of the gravure roll 1 Is a gravure coating machine for applying a heat resistant material to a separator for a lithium ion battery, wherein the gravure roll 1 of the gravure roll 1 is configured to be capable of changing at −60 ° ≦ θ ≦ 60 °. Lithium ion characterized in that the diameter ratio of the diameter D and the diameter d of the nipple 2 can be changed within a range of 1 ≦ D / d ≦ 5. It is a gravure coating machine for applying a heat-resistant material to a battery separator, and in order to change the drying state of the substrate 6, the substrate 6 is folded and passed through the drying furnace 11 twice or more. A gravure coating machine for applying a heat-resistant material to a separator for a lithium ion battery, wherein the drying state of the base material 6 is changed by changing the residence time, and the gravure head 3 Is a gravure coating machine for applying a heat-resistant material to a separator for a lithium ion battery, characterized in that both surfaces of the substrate 6 are coated, and the drying furnace 11 In the separator for a lithium ion battery, slits 8 for ejecting hot air are arranged in two or more places in the upper and lower parts in the drying furnace 11, and the drying furnace 11 is partitioned in one or two stages. Gravure for heat-resistant material application to a separator for a lithium ion battery, characterized in that it is a gravure coating machine for thermal material coating, and the winding speed of the substrate 6 is 5 m / min to 200 m / min It is a coating machine, and the same coating liquid 4 is made at the same speed by changing the angles of the gravure roll 1 and the nip roll 2 of the two gravure heads 3 and 3A at the entrance and exit of the drying furnace 11, respectively. A gravure coating machine for coating a heat-resistant material to a separator for a lithium ion battery, characterized in that the thickness and adhesiveness are changed depending on the state of the coating liquid 4 and the substrate 6 even when coated. Further, the heat resistance to the separator for a lithium ion battery, wherein the inorganic fine particle material in the coating liquid 4 is 30% or more and the average size of the inorganic fine particles is 10 μm or more and 100 μm or less. A gravure coating machine for coating materials, and using the gravure coating machine for coating a heat-resistant material to a lithium ion battery separator according to claim 1 or 2, the two gravure heads 3 are arranged facing each other. And a gravure coating machine for applying a heat-resistant material to a separator for a lithium ion battery, wherein one of the gravure heads 3 has the function of the nip roll 2, and the drying furnace 11 is a base material. A gravure coating machine for applying a heat-resistant material to a separator for a lithium ion battery, wherein both surfaces of the base material 6 are dried in a state of being floated in the drying furnace 11 without having a roll supporting 6. is there.

  The gravure coating machine for applying a heat-resistant material to a lithium ion battery separator according to the present invention can provide a highly safe film with improved heat resistance at a low cost.

DESCRIPTION OF SYMBOLS 1 Gravure roll 2 Nip roll 3.3A 1st, 2nd gravure head 4 Coating liquid 5 Meniscus 6 Base material 7 Line 8 Horizontal line 9 Feeding part 10 Gravure coating machine 11 Drying furnace 12 Outlet in drying furnace 13 Winding part 14 Hot air Slit 20 coating part

Claims (10)

  Application of heat-resistant materials to lithium ion battery separators with gravure roll (1) and nip roll (2) for applying heat-resistant organic or inorganic materials to substrate (6) via gravure head (3) In the gravure coating machine, for the gravure roll (1), the position of the nip roll (2) is a line (7) connecting the gravure roll (1) and the center (1A, 1B) of the nip roll (2). The lithium ion battery is characterized in that the angle θ intersecting the horizontal line (8) passing through the center (1A) of the gravure roll (1) can be changed within the range of −60 ° ≦ θ ≦ 60 °. Gravure coating machine for heat-resistant material coating on separators for automobiles.   The diameter ratio of the diameter (D) of the gravure roll (1) and the diameter (d) of the nipple (2) can be changed within a range of 1 ≦ D / d ≦ 5. Item 2. A gravure coating machine for applying a heat-resistant material to a lithium ion battery separator according to Item 1.   In order to change the drying state of the base material (6), the base material (6) is passed through the drying furnace (11) twice or more times, and the base material (6) is dried by changing the residence time. 3. A gravure coating machine for applying a heat-resistant material to a lithium ion battery separator according to claim 1, wherein the gravure coating machine is configured to change the state.   The separator for a lithium ion battery according to any one of claims 1 to 3, wherein the gravure head (3) is provided and two surfaces of the base material (6) are coated. Gravure coating machine for heat-resistant material coating.   In the drying furnace (11), slits (8) for blowing hot air are arranged in two or more places in the drying furnace (11), and the drying furnace (11) is divided into one or two stages. The gravure coating machine for heat-resistant material coating to the separator for lithium ion batteries according to claim 3.   2. The gravure coating machine for coating a heat-resistant material on a separator for a lithium ion battery according to claim 1, wherein the winding speed of the substrate (6) is 5 m / min to 200 m / min.   By changing the angle of the gravure roll (1) and nip roll (2) of the two gravure heads (3, 3A) at the inlet and outlet of the drying furnace (11), the same coating liquid (4) can be used. The separator for a lithium ion battery according to claim 6, wherein the thickness and adhesiveness are changed depending on the state of the coating liquid (4) and the base material (6) even when the coating is performed at a speed. Gravure coating machine for heat-resistant material coating.   The heat resistance of the separator for lithium ion batteries according to claim 6 or 7, wherein the inorganic fine particle material in the coating liquid (4) is 30% or more and the average size of the inorganic fine particles is in the range of 10 µm to 100 µm. Gravure coating machine for material coating.   Using the gravure coating machine for heat-resistant material coating to the lithium ion battery separator according to claim 1 or 2, the two gravure heads (3) are arranged facing each other, and one gravure head (3) is A gravure coating machine for applying a heat-resistant material to a separator for a lithium ion battery, which has the function of a nip roll (2).   The drying furnace (11) does not have a roll for supporting the base material (6), and dries both surfaces of the base material (6) in a state of being floated in the drying furnace (11). A gravure coating machine for applying a heat-resistant material to the lithium ion battery separator according to 9.

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