JP2011159434A - Separator and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separator where a heat-resistant layer is layered on a resin layer and adverse effects are not given to processes such as cutting or adhesion, and to provide a manufacturing method thereof. <P>SOLUTION: In the separator 10, the heat-resistant layer 12 is layered on the resin layer 11. On at least one surface of the resin layer 11, a hydrophilic property treated part 35 subjected to treatment to improve hydrophilic property and a hydrophilic property untreated part 39 not subjected to the treatment are provided. The heat-resistant layer 12 is formed on the hydrophilic property treated part 35 and is not formed on the hydrophilic property untreated part 39. A treatment to improve the hydrophilic property is, for example, corona treatment and a treatment to form the heat-resistant layer 12 is, for example, a gravure coating. Moreover, the cutting is performed in a range where the heat-resistant layer 12 is not formed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a separator used for, for example, a wound-type secondary battery and a manufacturing method thereof. More specifically, the present invention relates to a separator in which a resin layer and a ceramic layer are overlaid and a manufacturing method thereof.

  For example, some lithium ion secondary batteries use a so-called wound electrode body. The wound electrode body is obtained by winding a positive electrode plate, a negative electrode plate, and a separator, each of which is formed in a strip shape, in an appropriate manner. Conventionally, porous membranes made of porous organic polymers have been widely used as the separator. For example, what has what is called a shutdown function which consists of a composite material of PP (polypropylene) / PE (polyethylene) / PP is known. However, such a porous film may burn out when exposed to a higher temperature due to abnormal heat generation or the like.

  Therefore, a separator with improved heat resistance has been proposed by laminating a resin composition having high heat resistance on a porous film made of an organic polymer (see, for example, Patent Document 1). Furthermore, a separator is also disclosed in which a polymer nonwoven fabric is subjected to plasma treatment and a ceramic coating is provided thereon (see, for example, Patent Document 2). It is said that a separator that prevents peeling of the ceramic coating can be obtained by performing plasma treatment.

  On the other hand, for the convenience of manufacturing, a plurality of separators are manufactured by using a wide band-shaped resin film as a material and cutting along the longitudinal direction. When manufacturing a separator having a heat-resistant layer such as a ceramic layer as described above by using this manufacturing method, a heat-resistant layer is usually first laminated on the entire surface of a wide resin film, and then along the longitudinal direction. And cut into multiple sheets.

JP 2006-59733 A JP 2008-208511 A

  When the wide resin film having the heat-resistant layer formed on the entire surface as described above is cut along the longitudinal direction, the resin layer and the heat-resistant layer are cut together. However, when cutting ceramics or the like used in the heat-resistant layer, the cutting blade wears easily. When cutting is continued with a cutting blade having a worn portion, there is a problem that a part of the resin layer of the separator may remain in a protruding state (called “beard”). In addition, there is a problem that the heat-resistant layer near the cutting part may be peeled off from the resin film by the cutting process.

  Further, in the production of a wound body, an electrode plate or a separator is usually produced with an appropriate width longer than that required for one wound body, and wound around a winding core or the like. From there, roll it up and roll it over another sheet, wind it up to the required length, cut it, and make it into one wound body. In the case of manufacturing by such a method, the separator is cut at right angles to the longitudinal direction. In this case as well, there is a problem that when the heat-resistant layer is cut, the wear of the cutting blade tends to progress.

  Furthermore, in the wound body, for example, it is desirable to fix the wound body by welding a separator at the beginning or end of winding. Adhesion with adhesive tape or the like is possible, but it is not preferable because the cost of the tape is increased and the thickness of the wound body increases. However, the melting temperature of the heat-resistant layer is very high, and a separator having the heat-resistant layer formed on the entire surface cannot be welded at a normal welding temperature.

  The present invention has been made in order to solve the problems of the conventional separator and the manufacturing method thereof. That is, an object of the present invention is to provide a separator in which a heat-resistant layer is laminated on a resin layer and does not adversely affect the cutting and welding processes, and a method for manufacturing the separator.

  The separator of the present invention made for the purpose of solving this problem is a separator in which a heat-resistant layer is laminated on a resin layer, and at least one surface of the resin layer is subjected to a treatment for improving hydrophilicity. And a hydrophilic non-treated part that has not been subjected to a treatment for improving hydrophilicity, and the heat-resistant layer is formed on the hydrophilic treated part and on the hydrophilic non-treated part. Is not formed.

  According to the separator of the present invention, since the heat resistant layer is formed on the hydrophilic treated portion, the resin layer and the heat resistant layer are firmly bonded. The resin layer is also provided with a hydrophilic non-treated portion that is not formed with a heat-resistant layer and is not subjected to a treatment for improving hydrophilicity. In this range, the hydrophilicity is not improved, so even if some paint, which is a material of the heat-resistant layer, is adhered, a strong adhesion cannot be obtained, and it easily peels off. Therefore, since only the resin layer is reliably exposed in the hydrophilic non-processed portion, if cutting or welding is performed at this location, there is no possibility of adversely affecting those processes. For example, there is no fear that the wear of the cutting blade will be particularly advanced, and it is possible to effectively prevent the generation of beard. In addition, there is no possibility that fragments of the heat-resistant layer will be scattered during cutting or the heat-resistant layer in the vicinity of the cut portion will be peeled off. Furthermore, since it can weld easily and reliably if it is only the location of a resin layer, a winding body can also be formed without using an adhesive tape.

Furthermore, in the present invention, it is desirable that the hydrophilic non-treated portion is provided on at least one longitudinal edge of the resin layer. Moreover, the hydrophilic non-processing part may be provided in multiple places intermittently with respect to the longitudinal direction of the resin layer. Or the hydrophilic non-processing part may be provided in several places intermittently with respect to the longitudinal direction of a resin layer also in places other than a longitudinal direction edge part.
Depending on the relationship between the size of the resin layer prepared as a material and the size of the separator to be manufactured, a plurality of separators can be manufactured from the resin layer. For example, if the width of the resin layer is twice or more the width of the separator, the width is cut into two or more along the longitudinal direction of the resin layer. At this time, if a hydrophilic non-processed part is formed between them and a heat-resistant layer is formed on both sides thereof and cut at the hydrophilic non-processed part, the manufactured separator is provided with a hydrophilic non-processed part at the longitudinal edge. It will be what has been. In any case, the remainder of the hydrophilic non-treated portion in the resin layer is a hydrophilic treated portion.

Furthermore, in the present invention, it is desirable that the back surface of the hydrophilic non-treated portion in the resin layer is a surface not covered with the heat-resistant layer.
If it is such, the hydrophilic non-processed part in a resin layer will not be coat | covered with the heat-resistant layer on both surfaces. Therefore, there is no possibility that the cutting blade will be adversely affected by cutting at that point.

Further, the present invention is a method for manufacturing a separator by laminating a heat-resistant layer on a resin layer, and at least one surface of the resin layer is partially subjected to a treatment for improving hydrophilicity to provide a hydrophilic treated portion. In addition, the remaining portion is left as a hydrophilic non-treated portion that has not been subjected to a treatment for improving hydrophilicity, and a heat-resistant layer is formed on the hydrophilic-treated portion of the resin layer, and a heat-resistant layer is formed on the hydrophilic non-treated portion. It extends also to the manufacturing method of the separator which performs the coating process which does not form.
If it does in this way, the separator of the present invention can be manufactured. Further, even if a cutting step is included in the manufacturing process, the progress of wear of the cutting blade is suppressed, and the manufacturing can be performed without causing the beard of the resin layer or the peeling of the heat-resistant layer. Note that even if some paint is attached to the hydrophilic non-treated part, it does not mean that the place has been coated.

Furthermore, in the manufacturing method of the present invention, a resin film having a width of at least twice the width of the separator is prepared as a resin layer, and the treatment for improving hydrophilicity is corona discharge treatment, and the corona discharge treatment is divided into a plurality of parts. The electrodes are arranged in a row in the width direction of the resin layer so as to be separated from each other, so that the electrode is disposed opposite the portion to be the hydrophilic treated portion in the resin layer, and the hydrophilic non-treated portion in the resin layer. The electrode is not placed at the location opposite to the location that should be, and the coating process is a gravure coating process. The gravure coating process is applied to a gravure roll that is longer than the length of the resin layer in the width direction. Engraved part is formed in the part facing the property-treated part and the part not facing the hydrophilic non-treated part is not formed. Processing part In 囲内, it is desirable to produce two or more separators by cutting the resin layer in the longitudinal direction.
If it does in this way, the separator by which the hydrophilic non-processing part is provided in the at least one longitudinal direction edge part of the resin layer can be manufactured.

Further, in the production method of the present invention, the treatment for improving the hydrophilicity is corona discharge treatment, and in the corona discharge treatment, the discharge is performed only while the electrode faces the portion that should be the hydrophilic treated portion in the resin layer. In addition, no discharge is performed while the electrode is facing a portion that should be a hydrophilic non-treated portion in the resin layer, and the coating process is a gravure coating process. In the gravure coating process, the gravure roll is hydrophilic. It is desirable that the resin layer and the gravure roll are in contact with each other only while facing the property-treated portion, and that the resin layer and the gravure roll are not in contact with each other while the gravure roll is facing the hydrophilic non-treated portion. .
If it does in this way, the separator by which the hydrophilic non-processing part is provided in multiple places intermittently with respect to the longitudinal direction of the resin layer can be manufactured.

Furthermore, in the manufacturing method of the present invention, a resin film having a width of at least twice the width of the separator is prepared as a resin layer, and the treatment for improving hydrophilicity is corona discharge treatment, and the corona discharge treatment is divided into a plurality of parts. By arranging the electrodes separated from each other in a row in the width direction of the resin layer, the electrode is arranged opposite to the portion that can be a hydrophilic treated portion in the resin layer, and the hydrophilic non-treated portion in the resin layer In the state where the electrode is not disposed only at the portion that should be, the discharge is performed only while the electrode is opposed to the portion that should be the hydrophilic treated portion in the resin layer, and the hydrophilicity in the resin layer is not. Discharge is not performed while the electrode is facing the part to be the processing part. The coating process is a gravure coating process, and the gravure coating process is performed at a length longer than the length of the resin layer. G The gravure roll is hydrophilic when a sculpture part is formed at a position facing the hydrophilic treated part and a sculpture part is not formed only at a position facing the hydrophilic non-processed part. The resin layer and the gravure roll are brought into contact with each other only while facing the property-treated portion, and the resin layer and the gravure roll are not brought into contact with each other while the gravure roll faces the hydrophilic non-treated portion. After the coating treatment, two or more separators may be produced by cutting the resin layer in the longitudinal direction within the range of the hydrophilic non-treated portion.
If it does in this way, the separator by which the hydrophilic non-processing part is provided in multiple places intermittently with respect to the longitudinal direction of the resin layer also in places other than a longitudinal direction edge part can be manufactured.

  According to the separator of the present invention and the manufacturing method thereof, even a separator in which a heat-resistant layer is laminated on a resin layer does not adversely affect the cutting and welding processes.

It is a schematic sectional drawing which shows the separator of this form. It is explanatory drawing which shows the manufacturing process of a separator. It is a schematic block diagram which shows a corona treatment apparatus. It is a schematic block diagram which shows the coating apparatus of a heat-resistant layer. It is explanatory drawing which shows the example of the coating state in a comparative example. It is a schematic block diagram which shows the coating apparatus of a heat-resistant layer. It is explanatory drawing which shows the state in the middle of manufacture of a separator. It is description which shows the example of the coating state in an Example. It is description which shows the example of the coating state in a comparative example. It is a schematic sectional drawing which shows the separator which has a heat resistant layer on both surfaces. It is explanatory drawing which shows another example of the manufacturing method of a separator.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to a separator in which a heat-resistant layer is laminated on a resin layer and a manufacturing method for manufacturing the separator.

  As shown in FIG. 1, the separator 10 according to the present embodiment has a strip shape in which a heat-resistant layer 12 is laminated on a resin layer 11. For example, it is an insulator wound between positive and negative electrode plates in a wound type secondary battery. In the following, for a strip-like material such as a separator, the winding direction is referred to as the longitudinal direction (depth direction in the drawing), and the direction perpendicular to the longitudinal direction is referred to as the width direction (lateral direction in the drawing). The separator 10 has a roll shape for convenience during winding. That is, a width that is required for the secondary battery and longer than the required length is wound around a winding core or the like. Note that the separator 10 in FIG. 1 is shown in a considerably enlarged manner in the thickness direction (vertical direction in the figure) in this figure, but the actual thickness is very thin relative to the size in the width direction. .

  In the separator 10 of this embodiment, as shown in FIG. 1, the heat-resistant layer 12 is formed on the one surface of the resin layer 11 with a substantially uniform thickness. As the resin layer 11 of the separator 10 of this embodiment, a resin material film having electrical insulation can be used. For example, a porous film made of a composite material of PP / PE / PP may be used. Such a resin film has been widely used as a separator. The heat-resistant layer 12 is made of a material having electrical insulation properties and higher heat resistance than the resin layer 11. For example, ceramics are preferable. In this embodiment, the heat-resistant layer 12 is thinner than the thickness of the resin layer 11 and is, for example, about 1/4 to 1/6.

  In this embodiment, as a method of laminating the heat-resistant layer 12 on the resin layer 11, a method of laminating a ceramic material made into a water-based paint with a solvent containing water by gravure coating is adopted. Therefore, the heat resistant layer 12 can be firmly coated by improving the hydrophilicity of the resin layer 11 before performing the gravure coating. When the ceramic is coated without performing the treatment for improving the hydrophilicity, the heat-resistant layer 12 is easily peeled off, and an appropriate separator cannot be manufactured.

  With respect to the width direction, as shown in FIG. 1, the width B of the heat-resistant layer 12 is slightly smaller than the width A of the resin layer 11 of the separator 10. Of the upper surface 13 of the resin layer 11, the range of the width B where the heat-resistant layer 12 is provided is a range where hydrophilic treatment such as corona treatment or plasma treatment is performed before the heat-resistant layer 12 is formed. is there. That is, the range where the heat-resistant layer 12 is laminated is the hydrophilic processed portion.

  On the other hand, as shown in FIG. 1, there are unlaminated portions 15 in which the heat-resistant layer 12 is not laminated at both ends in the width direction of the separator 10. The non-laminated portion 15 is a range obtained by removing the width B from the above-described width A, and has a substantially same width C on both sides in the width direction. The non-laminated portion 15 is a range where the treatment for improving hydrophilicity has not been performed, and only the resin layer 11 is exposed. That is, the non-laminated portion 15 is a hydrophilic non-treated portion.

  For example, in a lithium ion secondary battery, the positive and negative electrode plates are usually formed by applying a mixture of each active material to a metal foil. When the separator 10 of this embodiment is used in such a lithium ion secondary battery, it is desirable that the width B of the heat-resistant layer 12 is not smaller than the width of any positive or negative active material mixture. The width C of the non-laminated portion 15 is at least 0.1 mm or more, more preferably about 1 mm or more.

  As will be described later, it is desirable that the separator 10 of this embodiment is provided with a range in which the heat-resistant layer 12 is not intermittently formed in the longitudinal direction. That is, when used in a lithium ion secondary battery, the resin layer 11 is preferably exposed with a certain width across the entire width direction at the portions corresponding to the beginning and end of winding. And the process which improves hydrophilicity is not performed also about this location. The length of the separator 10 used for one battery is appropriately selected according to the application.

Next, a method for manufacturing the separator 10 of this embodiment will be described. The manufacturing process of the separator 10 is performed according to the following procedure, as schematically shown in FIG. That is, as the material of the resin layer 11, a resin film 21 having a width about twice the width A of the resin layer 11 of the separator 10 is used.
-Corona treatment by the corona treatment device 23,
・ Coating process of ceramic layer by coating device 25,
The cutting process by the cutting device 27 is performed in this order.

  In this embodiment, as shown in FIG. 2, first, the corona treatment is performed on the resin film 21 by the corona treatment device 23. Corona treatment is a kind of plasma treatment and is a hydrophilicity improvement treatment for surface modification performed in the atmosphere and near atmospheric pressure. By performing this treatment, the hydrophilicity and adhesiveness of the surface can be improved, and the ceramic to be applied thereafter can be firmly attached to the resin film 21.

  The corona treatment device 23 includes a high-frequency power source 31, a controller 32, and an electrode 33, as schematically shown in FIG. The resin film 21 is wound around a grounded processing roll 34 and disposed so as to pass very close to the electrode 33 at a constant speed. A high frequency / high voltage output from the high frequency power supply 31 is applied between the electrode 33 and the processing roll 34 to generate corona discharge. The resin film 21 is passed under this corona discharge, and the energy of this discharge is applied to the resin film 21.

  In this embodiment, as shown in FIG. 2, the electrode 33 divided into two in the width direction is provided to perform corona treatment. Each electrode 33 has a size in the width direction equal to the width B of the heat-resistant layer 12 of the separator 10 and is arranged in a straight line in the width direction. Further, both the electrodes 33 are arranged at positions spaced from the width direction end of the resin film 21 by the width C of the non-laminated portion 15. Accordingly, a gap having a width twice as large as the width C is provided between the electrodes 33. Both electrodes 33 are of the same type and are similarly controlled by one controller 32.

  By disposing each electrode 33 as described above, two processed portions 35 are formed in a strip shape on the resin film 21 by this corona treatment step, as shown in FIG. And the resin film 21 which passed the corona treatment apparatus 23 has improved hydrophilicity and adhesiveness only in the processed part 35, and the non-processing parts 39, such as the both ends 37 and the intermediate part 38, remain intact. is there. In addition, the resin film 21 of the non-processing part 39 which has not performed corona discharge treatment is a thing with low wettability, and even if a ceramic material etc. adhere to the surface, it peels easily.

  Next, the ceramic layer is coated by the coating device 25. As shown in FIG. 4, the coating apparatus 25 of this embodiment is an apparatus that has a gravure roll 41, a liquid pan 42, a doctor blade 43, and a guide roll 44 and performs gravure coating. A paint 45 containing a ceramic material is supplied to the liquid pan 42. The gravure roll 41 is rotated while being partially immersed in the paint 45, and the paint 45 is attached to the surface of the gravure roll 41.

  Further, after the amount of the paint 45 attached to the surface of the gravure roll 41 is adjusted by the doctor blade 43, the gravure roll 41 and the resin film 21 are brought into contact with each other. The resin film 21 is pushed down by the two guide rolls 44 so that the portion between them is in contact with the gravure roll 41. Thereby, the coating material 45 is applied to the resin film 21. In this embodiment, water is added as a solvent for the paint 45.

  The gravure roll 41 of the present embodiment has a substantially cylindrical shape, and as shown in FIG. 2, engraving portions 47 are formed on the outer peripheral surface at two locations in the axial direction. The range in the width direction of the engraving portion 47 is the same location as the arrangement of the two electrodes 33 of the corona treatment device 23. That is, the engraving portions 47 having a width B are provided at two locations, and are arranged so as to face the processed portions 35 of the resin film 21, respectively.

  The engraving portion 47 is a portion where fine notches are formed on the surface of the gravure roll 41. Therefore, the gravure roll 41 can hold the paint 45 between the notches of the engraving portion 47. In the gravure roll 41, the portions other than the engraving portion 47 are smooth cylindrical surfaces that are not engraved. However, even if the doctor blade 43 is rubbed, the paint 45 other than the engraving portion 47 may not be completely wiped off. In this embodiment, it is not necessary to use a stepped roller having a narrow diameter other than the engraving portion 47 as the gravure roll 41, but this is not necessarily a stepped roller.

  In this embodiment, as shown in FIG. 2, the portion of the resin film 21 facing the engraving portion 47 is a treated portion 35 whose hydrophilicity has been improved by corona treatment. In the treated portion 35, the paint 45 easily adheres to the resin film 21. Therefore, the coating part 49 is formed on the processed part 35 of the resin film 21 by the processing by the coating apparatus 25. On the other hand, the other non-processing parts 39 (both ends 37 and intermediate part 38) are not subjected to corona treatment. Therefore, even if the paint 45 is slightly adhered to a portion other than the engraving portion 47 of the gravure roll 41, it hardly adheres to the resin film 21 other than the treated portion 35. Moreover, even if it adheres, it peels off easily.

  Next, cutting processing by the cutting device 27 is performed. That is, as shown in FIG. 2, the resin film 21 is cut along the longitudinal direction at the center position of the intermediate portion 38. Thereby, the resin film 21 becomes the two separators 10 each having the coating portion 49 formed thereon. In this embodiment, the resin film 21 is sandwiched between a circular cutting blade and a circular lower blade having a cutting auxiliary surface in contact with the cutting blade, and the cutting blade and the lower blade are rotated as the resin film 21 advances. Cutting (Gebel type) is performed.

  In this embodiment, no corona treatment is performed on the intermediate portion 38 cut by the cutting device 27. Therefore, the intermediate portion 38 has low wettability, and there is no possibility that ceramics are attached. For this reason, since there is no possibility that the cutting blade cuts the ceramic, wear of the cutting blade is effectively suppressed. Thereby, a part of the resin layer 11 is left uncut and protrudes during cutting, so that it is effectively prevented from becoming a so-called beard.

  On the other hand, even if the engraving portion 47 is formed on the gravure roll 41 as in the present embodiment, as shown in FIG. 5, when the corona treatment using the electrode 51 over the entire width direction of the resin film 21 is performed. , The favorable result cannot be obtained. In this way, since the entire width of the resin film 21 becomes the processed portion 52, the ceramic adhering portion 57 is formed in a somewhat speckled manner on the both end portions 54 and the intermediate portion 55 that are not opposed to the engraving portion 47. End up. This is because the paint 45 cannot be prevented from adhering to a portion other than the engraving portion 47 of the gravure roll 41 and the paint 45 is somewhat scattered during coating.

  In addition, when manufacturing the electrode winding body enclosed with a battery, the separator manufactured in the strip | belt shape of appropriate width | variety as mentioned above is wound with the positive electrode plate and negative electrode plate which were manufactured in strip | belt shape, respectively. Then, after winding up to the required length, cut and fix the end of winding to form a wound body. At this time, cutting is performed in a direction perpendicular to the longitudinal direction of the separator. Also in this case, it is not preferable to cut the portion coated with ceramics because the wear of the cutting blade proceeds. For this reason, in this embodiment, it is preferable to intermittently form uncoated places where ceramics are not applied in the direction perpendicular to the longitudinal direction during the coating process (see FIG. 7).

  Therefore, in this embodiment, the ceramic layer coating process is intermittently performed. And the timing which does not perform both a corona treatment and the coating process of a ceramic layer is set, sending the resin film 21 at a fixed speed | rate. That is, the controller 32 is set so as not to supply voltage to the electrode 33 during the period in which the corona treatment device 23 faces the portion of the resin film 21 where the ceramic layer is not applied. Accordingly, since the resin film 21 remains in a low hydrophilic state within this range, even if some ceramic is adhered, it is easily peeled off and does not remain adhered.

  Further, while the coating device 25 is facing a portion of the resin film 21 where the ceramic layer is not coated (a range where the corona treatment has not been performed), as shown in FIG. One of the rolls 44 is moved upward in the drawing. The operation of the coating apparatus 25 is not stopped, but the guide roll 44 is moved to a position away from the gravure roll 41. Thereby, since the resin film 21 and the gravure roll 41 do not contact at this location, the paint 45 is not applied to the resin film 21. Here, the guide roll 44 on the downstream side of the gravure roll 41 is moved in a direction substantially perpendicular to the surface of the resin film 21. It is preferable to continuously rotate the guide roll 44 so that the transport speed of the resin film 21 does not change. And if the part which does not apply a ceramic layer passes, the arrangement | positioning of the guide roll 44 will be returned and the coating process will be performed again.

  If it does in this way, as shown in FIG. 7, in addition to the both ends 37 and the intermediate part 38 of a longitudinal direction, the uncoated part 71 intermittent in the width direction is formed in the strip | belt-shaped resin film 21. . Therefore, the rectangular ceramic coating places 72 are arranged vertically and horizontally. Thereafter, the intermediate unit 38 is cut along the longitudinal direction by the cutting device 27. Thereby, it can be set as the separator 10 by which ceramics were intermittently applied.

  Furthermore, when forming an electrode winding body using the separator 10, the separator and positive and negative electrode plates are overlapped and unwound while being wound by a necessary length, and finally cut. In this embodiment, the cut portion of the separator 10 is the uncoated portion 71 shown in FIG. 7, and no ceramic is attached to this portion. Therefore, scattering of ceramic powder during cutting and progression of wear of the cutting blade due to cutting of the ceramic are effectively prevented. In addition, the amount of ceramic used is small compared to the case where ceramic is applied to the entire surface.

  In addition, by forming the intermittent uncoated part 71 in the separator 10 in this way, this uncoated part 71 is arrange | positioned at the both ends of a length direction when it is set as a wound body. Therefore, the separator can be welded at the beginning and end of winding of the wound body. For example, if two separators included in the wound body are welded at both ends, they can be easily fixed.

  The inventor confirmed these points through experiments. First, using the example using the electrode 33 divided as in the present embodiment and the comparative example 1 using one electrode 51 (see FIG. 5) acting on the entire width direction of the resin film 21, The coating process of the present Example was performed. In any of the examples, the same coating process was performed using the gravure roll 41 on which the engraving portion 47 was formed as described above, and the state of adhesion of the ceramic material at locations other than the engraving portion 47 was confirmed visually.

  In this experiment, the resin film 21 having a three-layer structure of PP / PE / PP and a thickness of 20 μm was used. The porosity was 47% and the air permeability was 300 seconds / 100 cc. A ceramic layer is formed on one side by applying a mixture of titania (titanium dioxide) / CMC (carboxymethylcellulose) / binder at a ratio of 98: 1: 1 to a thickness of 4 μm by the gravure coating method. did.

  As a result of this experiment, adhesion of ceramics to places other than the engraving portion 47 was not seen in the example. On the other hand, in Comparative Example 1, it was confirmed that some ceramics adhered to places other than the engraving portion 47. Therefore, it was confirmed that by selectively performing the corona discharge treatment, the adhesion of ceramics to other locations was effectively prevented.

  Next, the inventor has confirmed through further experiments that wear of the cutting blade is suppressed by cutting the intermediate portion 38 to which ceramics are not attached as in this embodiment. That is, using the same material as the above experiment, an example of this embodiment and a comparative example 2 in which the coating process was performed on one surface without providing the intermediate portion 38 were created. Each of these was started to be cut with a new cutting blade, and continuously cut continuously until each distance was cut, and the presence or absence of whiskers at the cut portions and the presence or absence of sliding of the ceramic layer were confirmed.

  Regarding the occurrence of beard, the last 10 m of cut surface was observed with an optical microscope (1000 times) for each cutting distance, and the presence or absence of beard was confirmed. In addition, regarding the sliding of the ceramic layer, adhesive tape was placed under the cutting blade with the adhesive surface facing upward during the cutting process, and the sliding objects during the cutting were collected. The adhesive tape was observed with an optical microscope (1000 times), and it was confirmed whether or not ceramics were contained therein.

  The results of the experiment are as shown in Table 1 above. In the examples, no generation of whiskers or ceramics was observed after cutting up to 80,000 m. On the other hand, in Comparative Example 2, no generation of whiskers or ceramics was seen when cutting up to 100 m, but ceramics already started to appear after cutting 5000 m. In addition, when cutting more than 10,000 m, generation of beard was also observed. Therefore, as compared with Comparative Example 2, it was confirmed that the abrasion of the cutting blade was suppressed in the Example.

  The inventor also conducted the following experiment. Using the same material as described above, the state of adhesion of the coating material to the uncoated portion 71 (see FIG. 7) in the case where the coating layer was intermittently formed in the longitudinal direction was confirmed. In the example of this experiment, both corona treatment and gravure coating treatment were performed intermittently. In the comparative example, corona treatment was performed continuously and only gravure coating was performed intermittently.

  As a result of the experiment, in the example, as shown in FIG. 8, the boundary between the ceramic coated portion 72 and the uncoated portion 71 is clear, and adhesion of ceramics to the uncoated portion 71 was not seen. . On the other hand, in the comparative example, as shown in FIG. 9, the protrusion 81 from the ceramic coating portion 72 to the uncoated portion 71, the spot-like scattering 82 into the uncoated portion 71, and the like were observed. That is, it was not possible to completely prevent the ceramics from adhering to the uncoated portion 71.

  As described above in detail, the separator 10 of this embodiment is obtained by providing the resin layer 11 with the heat-resistant layer 12 made of ceramics. Therefore, it has high heat resistance and can be suitably used for, for example, an electrode body of a lithium ion secondary battery. Furthermore, according to the manufacturing method of the present embodiment, the range in which the heat-resistant layer 12 is formed leaving the cut portion is set, and the corona treatment is applied only within the range and the ceramic is applied. Is prevented from adhering. Therefore, there is no possibility that the cutting blade will hit the ceramic, and wear of the cutting blade is suppressed. Thereby, the separator 10 can be efficiently manufactured using the resin film 21 twice the width of the separator 10. Therefore, a separator in which a heat-resistant layer is laminated on a resin layer and can be manufactured without causing the beard of the resin layer or the peeling of the heat-resistant layer even when manufactured using a wide band-shaped resin material.

In addition, this form is only a mere illustration and does not limit this invention at all. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof.
For example, in this embodiment, the resin film 21 having a width twice that of the separator 10 is used to cut the film into two pieces. However, the separator may be manufactured by cutting a film having a width three times or more into three pieces or more. Of course it is possible. In that case, corona treatment and coating treatment are performed according to the arrangement of the heat-resistant layer of each separator. And what is necessary is just not to perform a corona treatment in the location to cut | disconnect.

  Further, in the above embodiment and FIG. 1, the heat-resistant layer 12 is formed only on one surface of the resin layer 11, but as shown in FIG. 10, heat-resistant layers are formed on both the front and back surfaces of the resin layer. The separator 60 may be used. In this case, the heat-resistant layer is first formed on one side as described above, and then the heat-resistant layer is similarly formed on the opposite side at the same position. Then, what is necessary is just to cut | disconnect the non-laminated part arrange | positioned in the same position on both surfaces to make the separator 60. FIG.

  Further, in the above embodiment, the ceramic film is not applied to both ends of the resin film 21 in the width direction, and the non-laminated portions 15 having the width C are provided at both ends of the separator 10. There may not be a laminated part. For example, as shown in FIG. 11, a heat-resistant layer 63 is laminated on a resin film 61 having a width approximately three times that of the separator, leaving two non-laminated parts 62, and this is cut at the non-laminated part 62. Thus, three separators can be manufactured. In this case, as a matter of course, a gravure roll in which three engraved portions are formed is used, and the hydrophilicity improving process is not performed on the non-laminated portion 62. When manufactured in this way, as the separator after cutting, a separator having a non-laminated portion at both ends in the width direction and a separator having only one side are mixed. Nevertheless, there is no particular problem when used for secondary batteries.

DESCRIPTION OF SYMBOLS 10 Separator 11 Resin layer 12 Heat-resistant layer 21 Resin film 23 Corona treatment apparatus 25 Coating apparatus 33 Electrode 35 Treated part 39 Untreated part 41 Gravure roll 47 Engraving part

Claims (9)

In a separator made by laminating a heat-resistant layer on a resin layer,
On at least one side of the resin layer,
A hydrophilic treated part that has been treated to improve hydrophilicity;
A non-hydrophilic portion that has not been subjected to a treatment for improving hydrophilicity,
The separator is characterized in that the heat-resistant layer is formed on the hydrophilic treated portion and is not formed on the hydrophilic non-treated portion. The separator according to claim 1,
The said hydrophilic non-process part is provided in the at least one longitudinal direction edge part of the said resin layer, The separator characterized by the above-mentioned. The separator according to claim 1,
The said hydrophilic non-processing part is provided in multiple places intermittently with respect to the longitudinal direction of the said resin layer, The separator characterized by the above-mentioned. The separator according to claim 2,
The separator is characterized in that the hydrophilic non-treated portion is provided at a plurality of locations intermittently with respect to the longitudinal direction of the resin layer at locations other than the longitudinal edge portion. In the separator according to any one of claims 1 to 4,
The separator characterized by the back surface of the said hydrophilic non-processing part in the said resin layer being the surface which is not coat | covered with the said heat-resistant layer. In the manufacturing method of a separator by laminating a heat-resistant layer on a resin layer,
At least one surface of the resin layer is partially subjected to a treatment for improving hydrophilicity to provide a hydrophilic treated portion, and the remaining portion is left as a hydrophilic non-treated portion not subjected to a treatment for improving hydrophilicity,
The separator manufacturing method characterized by performing the coating process which does not form the said heat resistant layer on the said hydrophilic non-processed part while forming the said heat resistant layer on the said hydrophilic processed part in the said resin layer. In the manufacturing method of the separator of Claim 6,
Preparing a resin film having a width of at least twice the width of the separator as the resin layer;
The treatment for improving the hydrophilicity is a corona discharge treatment,
In the corona discharge treatment, the electrodes divided into a plurality of pieces are separated from each other and arranged in a line in the width direction of the resin layer, so as to face the portion to be the hydrophilic treated portion in the resin layer. In the state where the electrode is disposed and the electrode is not disposed at a position opposite to the portion to be the hydrophilic non-treated portion in the resin layer,
The coating process is a gravure coating process,
In the gravure coating treatment, a gravure roll having a length in the width direction of the resin layer or longer is formed with a sculpture portion at a location facing the hydrophilic treated portion, and opposed to the hydrophilic non-treated portion. Use the part where the sculpture part is not formed in
After the coating treatment, within the range of the hydrophilic non-treated portion, two or more separators are produced by cutting the resin layer in the longitudinal direction. In the manufacturing method of the separator of Claim 6,
The treatment for improving the hydrophilicity is a corona discharge treatment,
In the corona discharge treatment, discharge is performed only while an electrode is opposed to a portion to be the hydrophilic treated portion in the resin layer, and at a portion to be the hydrophilic non-treated portion in the resin layer. No discharge occurs while the electrodes are facing each other,
The coating process is a gravure coating process,
In the gravure coating treatment, the resin layer and the gravure roll are brought into contact with each other only while the gravure roll is opposed to the hydrophilic processed portion, and the gravure roll is opposed to the hydrophilic non-treated portion. A method for producing a separator, wherein the resin layer and the gravure roll are not brought into contact with each other. In the manufacturing method of the separator of Claim 6,
Preparing a resin film having a width of at least twice the width of the separator as the resin layer;
The treatment for improving the hydrophilicity is a corona discharge treatment,
In the corona discharge treatment, the electrodes divided into a plurality of parts are separated from each other and arranged in a row in the width direction of the resin layer, so that the electrodes are opposed to locations that can be the hydrophilic treated portions in the resin layer. Is disposed in the resin layer in a state where the electrode is not disposed only in a portion facing the hydrophilic non-treated portion in the resin layer. The discharge is performed only while the electrodes are opposed to each other, and the discharge is not performed while the electrodes are opposed to the portion to be the hydrophilic non-treated portion in the resin layer,
The coating process is a gravure coating process,
In the gravure coating treatment, a gravure roll having a length in the width direction of the resin layer or longer is formed with a sculpture portion at a location facing the hydrophilic treated portion, and only in the hydrophilic non-treated portion. Using the one where the engraving part is not formed at the opposite part, the gravure roll is in contact with the resin layer and the gravure roll only while the gravure roll faces the hydrophilic treated part, Do not let the resin layer and the gravure roll contact each other while facing the hydrophilic non-treated part,
After the coating treatment, within the range of the hydrophilic non-treated portion, two or more separators are produced by cutting the resin layer in the longitudinal direction.

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