JP2013030363A - Separator, separator manufacturing device, and separator manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separator capable of suppressing a decrease in liquid permeability of the separator and achieving a higher electrolyte absorbability than and a lower ion resistance than the conventional separators, also to provide a separator manufacturing device capable of manufacturing the separator as described above, and further to provide a separator manufacturing method capable of manufacturing the separator as described above.SOLUTION: A separator 1 comprises: a base material layer 10; and a nanofiber layer 20 including at least a joining nanofiber 22 used to join with the base material layer 10. The base material layer 10 and the nanofiber layer 20 are joined by the joining nanofiber 22.

Description

  The present invention relates to a separator, a separator manufacturing apparatus, and a separator manufacturing method.

  Conventionally, a separator having a base material layer and a nanofiber layer containing nanofibers is known (for example, see Patent Document 1).

According to the conventional separator, it is possible to obtain a separator having various properties by using a base material layer and a nanofiber layer having different properties.
In addition, according to the conventional separator, it is possible to obtain a separator having more various properties by adding the properties (wide surface area, fine voids, etc.) of the nanofiber layer to the properties of the base material layer. Become.
Also, according to the conventional separator, compared with a separator having a general fiber layer, it has a nanofiber layer with a fine fiber average diameter and fine voids, so it has high electrolyte absorption, low ion resistance and high dendrite. It is possible to provide a separator having resistance and a thin total thickness.

The “base material layer” refers to a layer that becomes a base material for forming the nanofiber layer.
The “nanofiber” refers to a fiber made of a polymer material and having an average diameter of several nm to several thousand nm. Furthermore, the “separator” refers to a separator (partition) used for a battery (including a primary battery and a secondary battery), a capacitor (also referred to as a capacitor), and the like.

JP 2010-103050 A

  By the way, in the technical field of separators, it is known that the bond strength between the base material layer and the nanofiber layer may be small (that is, easy to peel off). For this reason, joining a base material layer and a nanofiber layer using various joining materials is performed (for example, refer to [0040] paragraph of patent documents 1). However, according to the research of the inventors of the present invention, in such cases, the liquid permeability of the separator is lowered, and as a result, it is difficult to realize higher electrolyte absorption and lower ionic resistance. It turns out that there is a problem.

  Therefore, the present invention has been made to solve the above-described problems, and it is possible to suppress a decrease in liquid permeability of the separator. It aims at providing the separator which can implement | achieve much lower ionic resistance. Moreover, it aims at providing the separator manufacturing apparatus which can manufacture the above separators. Furthermore, it aims at providing the separator manufacturing method which can manufacture the above separators.

  The inventors of the present invention have intensively studied that the liquid permeability of the separator is reduced by bonding the base material layer and the nanofiber layer, and as a result, the gap between the nanofibers is filled with the bonding material. I found out that this is the cause. In light of this, the inventors of the present invention have made further studies and arrived at the idea that the above problem can be solved by using nanofibers as the bonding material (see the embodiments described later). The present invention has been completed. The present invention includes the following elements.

[1] The separator of the present invention has a base material layer and a nanofiber layer containing at least joint nanofibers (as a joining material) used for joining the base material layer, The nanofiber layer is bonded by the bonded nanofiber.

  For this reason, according to the separator of the present invention, since it has a nanofiber layer including at least a bonding nanofiber used for bonding to a base material layer, the bonding nanofiber as a bonding material is very fine, and thus after bonding It is possible to suppress the gap between the nanofibers from being filled, and as a result, it is possible to suppress a decrease in the liquid permeability of the separator, and the electrolyte absorption is higher than that of the conventional separator. Performance and lower ionic resistance can be realized.

  In addition, according to the separator of the present invention, by using a base material layer and a nanofiber layer having different properties, it is possible to obtain a separator having various properties as in the case of a conventional separator.

  In addition, according to the separator of the present invention, by adding the properties of the nanofiber layer (such as a large surface area and fine voids) to the properties of the base material layer, as with conventional separators, more diverse properties can be obtained. It becomes possible to set it as the separator which has.

  In addition, according to the separator of the present invention, since it has a nanofiber layer with a fine fiber average diameter and voids compared to a separator having a general fiber layer, it has a high electrolyte solution absorbency like a conventional separator. It has low ion resistance and high dendrite resistance, and can be a separator having a thin total thickness.

[2] In the separator of the present invention, the bonded nanofibers are made of a resin having thermal bondability, and the base material layer and the nanofiber layer are bonded by bonded nanofibers at least partially melted by heat. It is preferable that

  By setting it as such a structure, it becomes possible to join a base material layer and a nanofiber layer easily by heating.

  The resin having thermal bondability refers to a resin widely including a resin having thermal bondability such as polyurethane in addition to a so-called thermoplastic resin (polyethylene, polypropylene, etc.).

[3] In the separator of the present invention, it is preferable that the melting point of the resin having the heat bonding property constituting the bonding nanofiber is lower than the melting point of the material forming the base material layer.

  With such a configuration, the bonded nanofibers can be selectively melted by heating.

[4] In the separator of the present invention, it is preferable that the melting point of the heat-bonding resin constituting the bonding nanofiber is lower by 10 ° C. or more than the melting point of the material forming the base material layer.

  With such a configuration, the bonded nanofibers can be easily selectively melted by heating.

[5] In the separator of the present invention, the average diameter of the bonded nanofiber is preferably in the range of 50 nm to 1000 nm.

  By setting it as such a structure, it becomes possible to join a base material layer and a nanofiber layer with sufficient intensity | strength, and to suppress that the liquid permeability of a separator falls.

  In the present invention, the reason that the average diameter of the bonded nanofibers is in the range of 50 nm to 1000 nm is that when the average diameter is smaller than 50 nm, it may not be possible to bond with sufficient strength, This is because when the average diameter is larger than 1000 nm, the liquid permeability of the separator may be lowered.

[6] In the separator of the present invention, it is preferable that the nanofiber layer further includes a high melting point nanofiber made of a material having a melting point higher than that of the resin having thermal bondability.

  By setting it as such a structure, it becomes possible to suppress that the structure of the nanofiber layer that the average diameter and the space | gap of a fiber are fine breaks.

[7] In the separator of the present invention, the bonding nanofiber is made of a resin having solubility in a predetermined solvent, and at least a part of the base material layer and the nanofiber layer is the predetermined solvent. It is also preferable that the bonded nanofibers dissolved in (1) are bonded.

  By setting it as such a structure, it becomes possible to join a base material layer and a nanofiber layer easily using a predetermined solvent.

  Examples of the predetermined solvent include various solvents such as dichloromethane, dimethylformamide, dimethyl sulfoxide, methyl ethyl ketone, chloroform, acetone, water, formic acid, acetic acid, cyclohexane, and THF. A plurality of types of solvents may be mixed and used.

[8] In the separator of the present invention, the nanofiber layer is a low-solubility nanofiber made of a material having lower solubility in the predetermined solvent than a resin having solubility in the predetermined solvent. It is preferable that it is further included.

  By setting it as such a structure, it becomes possible to suppress that the structure of the nanofiber layer that the average diameter and the space | gap of a fiber are fine breaks.

[9] In the separator of the present invention, the thickness of the separator is preferably in the range of 1 μm to 100 μm.

With such a configuration, it is possible to obtain a separator having sufficient mechanical strength and sufficiently low ion resistance.
In the present invention, the thickness of the separator is set in the range of 1 μm to 100 μm because the mechanical strength of the separator may not be sufficiently increased when the thickness is less than 1 μm. This is because if the thickness is greater than 100 μm, the ion resistance may not be sufficiently lowered.
From the above viewpoint, the thickness of the separator is more preferably in the range of 10 μm to 40 μm.

[10] In the separator of the present invention, the bonded nanofiber is preferably obtained by an electrospinning method.

  With such a configuration, it is possible to form a nanofiber layer having desired properties (composition, thickness, basis weight, average diameter of bonded nanofibers, melting temperature, solubility in a solvent, and the like).

[11] The separator manufacturing apparatus of the present invention includes an electrospinning apparatus in which a nanofiber layer including bonded nanofibers is formed on one surface of a base material layer by an electrospinning method to form a nanofiber laminate; A joining device for joining the base material layer and the nanofiber layer using the joining nanofibers in a fiber laminate is provided.

  According to the separator manufacturing apparatus of the present invention, the separator of the present invention as described above can be manufactured.

[12] In the separator manufacturing apparatus of the present invention, it is preferable that the joining device includes a thermal joining device that performs thermocompression bonding in a state where the base material layer and the nanofiber layer are laminated.

  With such a configuration, when bonded nanofibers made of a resin having thermal bondability are used as bonded nanofibers, the base material layer and the nanofiber layers can be bonded by heating.

[13] In the separator manufacturing method of the present invention, a nanofiber layer including bonded nanofibers is formed on one surface of the base material layer by a base material layer preparing step of preparing the base material layer and an electrospinning method. An electrospinning step of forming a nanofiber laminate, and a joining step of joining the base material layer and the nanofiber layer in this order using the joining nanofibers in the nanofiber laminate. To do.

  According to the separator manufacturing method of the present invention, the separator of the present invention as described above can be manufactured.

[14] In the separator manufacturing method of the present invention, the joining step is a thermal joining step of thermocompression bonding in a state where the base material layer and the nanofiber layer are laminated, and the joining nanostructure is formed by the thermal joining step. It is preferable that at least a part of the fiber is melted and the base material layer and the nanofiber layer are bonded with the bonded nanofiber.

  By setting it as such a method, when the joining nanofiber which consists of resin which has heat bondability as a joining nanofiber is used, it becomes possible to join a base material layer and a nanofiber layer by heating.

It is a figure for demonstrating the separator 1 which concerns on Embodiment 1. FIG. 1 is a front view of a separator manufacturing apparatus 100 according to Embodiment 1. FIG. 3 is a flowchart of a separator manufacturing method according to Embodiment 1. It is a figure for demonstrating the separator manufacturing method which concerns on Embodiment 1. FIG. It is a figure shown in order to demonstrate joining process S3 in Embodiment 1. FIG. 6 is a diagram for explaining a separator 2 according to Embodiment 2. FIG. It is a flowchart of the separator manufacturing method in a modification.

  Hereinafter, the separator of the present invention, a separator manufacturing device, and a separator manufacturing method are explained based on an embodiment shown in a figure.

[Embodiment 1]
1. Configuration of Separator 1 According to Embodiment 1 First, the configuration of the separator 1 according to Embodiment 1 will be described.
FIG. 1 is a view for explaining a separator 1 according to the first embodiment. FIG. 1A is a perspective view of the separator 1 wound around a core (not shown), FIG. 1B is an enlarged cross-sectional view of the separator 1, and FIG. It is the schematic diagram (henceforth an enlarged schematic diagram) which expands further and shows the range shown by A of FIG.1 (b).

As shown in FIG. 1, the separator 1 according to Embodiment 1 includes a base material layer 10 and a nanofiber layer 20. In the separator 1, as shown in FIG. 1C, the base material layer 10 and the nanofiber layer 20 are bonded by bonded nanofibers 22. Specifically, the base material layer 10 and the nanofiber layer 20 are bonded by bonded nanofibers 24 at least partially melted by heat.
The thickness of the separator 1 is in the range of 1 μm to 100 μm, for example, 20 μm.

  As described later, the separator 1 according to the first embodiment can be obtained by the separator manufacturing method according to the first embodiment using the separator manufacturing apparatus 100 according to the first embodiment.

The base material layer 10 takes the form of a long sheet, and as the base material layer 10, a non-woven fabric, a woven fabric, a knitted fabric, paper, or the like made of various materials can be used. In Embodiment 1, a fibrous base material layer is used as the base material layer 10, and reference numeral 12 in FIG. 1C denotes the base material fiber in the base material layer 10. In addition, as the base material layer 10, things other than a fiber (for example, a porous film) can also be used.
The base layer 10 may have a thickness of 1 μm to 90 μm, for example. The length of the base material layer 10 can be, for example, 10 to 10 km.

  The nanofiber layer 20 is composed of bonded nanofibers 22 used for bonding to the base material layer 10. In addition, the nanofiber layer should just contain the joining nanofiber at least, and if it is on it, it may contain substances other than joining nanofiber. The bonded nanofiber 22 is made of a resin having thermal bondability. The average diameter of the bonding nanofiber 22 is in the range of 50 nm to 1000 nm, for example, 100 nm. The bonded nanofiber 22 can be obtained by an electrospinning method as described later.

  In the separator 1, the melting point of the resin having thermal bondability constituting the bonded nanofiber 22 is lower than the melting point of the material (base material layer fiber 12) constituting the base layer 10, and more specifically, 10 ° C. or higher. Low.

2. Configuration of Separator Manufacturing Apparatus 100 According to Embodiment 1 Next, the configuration of the separator manufacturing apparatus 100 according to Embodiment 1 will be described.
FIG. 2 is a front view of the separator manufacturing apparatus 100 according to the first embodiment. In FIG. 2, some members (such as the casing 200 and the raw material tank 232) are shown as cross-sectional views.

  The separator manufacturing apparatus 100 includes a transport device 110, an electrospinning device 120, and a joining device 130. The separator manufacturing apparatus 100 includes one electrospinning apparatus 120.

  The transport device 110 transports the base material layer 10 at a predetermined transport speed. The transport device 110 includes a feed roller 111 that feeds the base material layer 10, a take-up roller 112 that winds the base material layer 10, tension rollers 113 and 118 that adjust the tension of the base material layer 10, and the feed roller 111 and the take-up roller 112. Auxiliary roller 114 located between the two. The feed roller 111 and the take-up roller 112 are configured to be rotated by a drive motor (not shown).

The electrospinning apparatus 120 forms the nanofiber layer 20 ′ including the bonded nanofibers 22 on one surface (the lower surface in the first embodiment) of the base material layer 10 by an electrospinning method to form a nanofiber laminate. 30 (see FIG. 4B described later).
As shown in FIG. 2, the electrospinning device 120 includes a housing 200, a nozzle unit 210, a polymer solution supply unit 230, a collector 250, a power supply device 260, and an auxiliary belt device 270. The electrospinning apparatus 120 discharges the polymer solution from the discharge ports of a plurality of upward nozzles 220, which will be described later, to form the nanofiber layer 20 ′.

The housing 200 is made of a conductor.
The nozzle unit 210 has a plurality of upward nozzles 220.
Nozzle units having various sizes and shapes can be used in the separator manufacturing apparatus of the present invention, but the nozzle unit 210 has a rectangular shape (a square shape having a side of 0.5 m to 3 m when viewed from the upper surface. It has a block-like shape with a visible size.

  The upward nozzle 220 is a nozzle that discharges “a polymer solution that is a raw material of the bonding nanofiber 22 (a polymer solution of a resin having thermal bonding properties)” supplied from the polymer solution supply unit 230 from a discharge port. The upward nozzle 220 discharges the polymer solution upward from the discharge port. As the material constituting the upward nozzle 220, a conductor can be used, and for example, copper, stainless steel, aluminum, or the like can be used.

  The upward nozzles 220 are arranged at a pitch of 1.5 cm to 6.0 cm, for example. The number of upward nozzles 220 may be, for example, 36 (6 × 6 when arranged in the same vertical and horizontal directions) to 21904 (148 × 148 when arranged in the same vertical and horizontal directions).

  In the first embodiment, the upward nozzle 220 is used as the nozzle, but the present invention is not limited to this. A horizontal nozzle may be used as the nozzle, or a downward nozzle may be used.

  The polymer solution supply unit 230 supplies the polymer solution to the nozzle unit 210. The polymer solution supply unit 230 includes a raw material tank 232, a stirring device 233, and a supply device 234. The raw material tank 232 of the electrospinning apparatus 120 contains the raw material of the bonded nanofiber 22.

The collector 250 is disposed above the nozzle unit 210. The collector 250 is made of a conductor and is attached to the housing 200 via an insulating member 252 as shown in FIG.
The power supply device 260 applies a high voltage between the upward nozzle 220 and the collector 250. The positive electrode of the power supply device 260 is connected to the collector 250, and the negative electrode of the power supply device 260 is connected to the nozzle unit 210 via the housing 200.

  The auxiliary belt device 270 includes an auxiliary belt 272 that rotates in synchronization with the conveyance speed of the long sheet W, and five auxiliary belt rollers 274 that assist the rotation of the auxiliary belt 272. Of the five auxiliary belt rollers 274, one or more auxiliary belt rollers are drive rollers, and the remaining auxiliary belt rollers are driven rollers. Since the auxiliary belt 272 is disposed between the collector 250 and the base material layer 10, the base material layer 10 is smoothly conveyed without being attracted to the collector 250 to which a positive high voltage is applied. become.

  The bonding device 130 is a device that bonds the base material layer 10 and the nanofiber layer 20 using the bonded nanofibers 22 in the nanofiber laminate 30. The bonding apparatus 130 is a thermal bonding apparatus that performs thermocompression bonding in a state where the base material layer 10 and the nanofiber layer 20 ′ are stacked. As the joining apparatus 130, as shown in FIG. 2, the thermal joining apparatus provided with the calendar roll can be illustrated. In addition, as a means for heating, what incorporated the heater function (not shown) in the calendar roll can be used, for example, but besides this, for example, a resistance heater, an infrared heater, It is also possible to use a dryer, a hot air generator or the like. In addition, in FIG. 2, although the calender roll illustrated the thing of the structure which pinches | interposes the nanofiber laminated body 30 with an upper and lower roller one by one, it is not restricted to such a structure, Upper and lower two each It is possible to use a calendar roll having various configurations, such as those having a roller.

3. Description of Separator Manufacturing Method According to Embodiment 1 Next, a separator manufacturing method according to Embodiment 1 will be described.
FIG. 3 is a flowchart of the separator manufacturing method according to the first embodiment.
FIG. 4 is a diagram for explaining the separator manufacturing method according to the first embodiment. 4A is an enlarged cross-sectional view of the base material 10 in the base material preparing step S1, and FIG. 4B is an enlarged cross-sectional view of the nanofiber laminate 30 after the joining electrospinning step S2.
FIG. 5 is a view for explaining the joining step S3 in the first embodiment. FIG. 5A is an enlarged schematic diagram before the joining step S3, and FIG. 5B is an enlarged schematic diagram after the joining step S3.

  As shown in FIG. 3, the separator manufacturing method according to Embodiment 1 includes a base material layer preparation step S1, an electrospinning step S2, and a joining step S3 in this order. The separator manufacturing method according to the first embodiment is performed using the separator manufacturing apparatus 100 according to the first embodiment.

1. Base material layer preparation step S1
The base material preparation step S1 is a step of preparing the base material layer 10 as shown in FIG. In the first embodiment, the base material layer 10 takes the form of a long sheet. In addition, in the separator manufacturing method of this invention, the base material layer of the various shapes which take forms other than a long sheet can also be used.

2. Electrospinning process S2
In the electrospinning step S2, as shown in FIG. 4 (b), the nanofiber layered product is formed by forming the nanofiber layer 20 ′ including the bonded nanofibers 22 on one surface of the base material layer 10 by the electrospinning method. 30.
Specifically, first, a polymer solution that is a raw material of the bonded nanofibers 22 is supplied to the nozzle unit 210 through the polymer solution supply unit 230 in the electrospinning apparatus 120. Next, the base material layer 10, which is a long sheet, is set on the transport device 110, and the nanofibers are formed on the base material layer 10 in the electrospinning device 120 while the base material layer 10 is transported from the feeding roller 111 at a predetermined transport speed. A layer 20 ′ is formed to form a nanofiber laminate 30.

3. Joining step S3
As shown in FIG. 5, the bonding step S <b> 3 is a step of bonding the base material layer 10 and the nanofiber layer 20 using the bonded nanofibers 22 in the nanofiber laminate 30. The joining step S3 is a thermal joining step in which the base material layer 10 and the nanofiber layer 20 ′ are laminated and thermocompression bonded, and at least a part of the joined nanofibers 22 is melted by the thermal joining step. The layer 10 and the nanofiber layer 20 are bonded with bonded nanofibers 22. The said process is performed by the joining apparatus 130 of the separator manufacturing apparatus 100, and the separator 1 is manufactured. The manufactured separator 1 is wound around the winding roller 112.

  Below, the spinning conditions in Embodiment 1 are shown as an example.

  As a material of the bonding nanofiber 22, a resin having thermal bonding properties, for example, polyvinylidene fluoride (PVDF), polylactic acid (PLA), polypropylene (PP), polyethylene (PE), polyvinyl acetate (PVAc), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyamide (PA), polyurethane (PUR), polyvinyl alcohol (PVA), polyacrylonitrile (PAN), polyimide (PI), polyetherimide (PEI) ), Polycaprolactone (PCL), polylactic acid glycolic acid (PLGA), and the like. As the material of the bonding nanofiber 22, a material having a melting point lower than the melting point of the material constituting the base material layer 10, more specifically, a melting point lower by 10 ° C. or more can be suitably used.

  As a solvent for producing various polymer solutions, for example, dichloromethane, dimethylformamide, dimethyl sulfoxide, methyl ethyl ketone, chloroform, acetone, water, formic acid, acetic acid, cyclohexane, THF and the like can be used. Moreover, you may mix and use multiple types of solvent as a solvent. The polymer solution may contain an additive such as a conductivity improver.

  A conveyance speed can be set to 0.2 m / min-100 m / min, for example. The voltage applied to the upward nozzle 220, the collector 250, and the nozzle unit 210 can be set to 10 kV to 80 kV, and is preferably set to around 50 kV.

  The temperature of the spinning zone can be set at 25 ° C., for example. The humidity of the spinning area can be set to 30%, for example.

  Hereinafter, effects of the separator 1, the separator manufacturing apparatus 100, and the separator manufacturing method according to the first embodiment will be described.

  According to the separator 1 according to the first embodiment, since the nanofiber layer 20 including at least the bonded nanofibers 22 used for bonding to the base material layer 10 is included, the bonded nanofibers as the bonding material are very fine. , It becomes possible to prevent the gap between the nanofibers from being filled after bonding, and as a result, it is possible to suppress the decrease in liquid permeability of the separator, which is higher than that of the conventional separator. It is possible to achieve electrolyte absorption and lower ionic resistance.

  Moreover, according to the separator 1 which concerns on Embodiment 1, it can be set as the separator which has various properties like the conventional separator by using the base material layer 10 and the nanofiber layer 20 which have a respectively different property. It becomes possible.

  Moreover, according to the separator 1 which concerns on Embodiment 1, by adding the property (a large surface area, a fine space | gap, etc.) which the nanofiber layer 20 has to the property which the base material layer 10 has, similarly to the conventional separator, A separator having more various properties can be obtained.

  Moreover, according to the separator 1 which concerns on Embodiment 1, since the average diameter of a fiber and the space | gap are provided with the nanofiber layer 20 compared with the separator which has a general fiber layer, it is high like the conventional separator. It has electrolyte absorption, low ionic resistance, and high dendrite resistance, and can be a separator with a thin total thickness.

  Moreover, according to the separator 1 which concerns on Embodiment 1, the joining nanofiber 22 consists of resin which has heat bondability, and the base material layer 10 and the nanofiber layer 20 are joining nanofiber which at least one part fuse | melted with the heat | fever. Therefore, the base material layer and the nanofiber layer can be easily joined by heating.

  Moreover, according to the separator 1 which concerns on Embodiment 1, since melting | fusing point of the resin which has the heat bondability which comprises the joining nanofiber 22 is lower than melting | fusing point of the material which comprises the base material layer 10, joining nanofiber by heating Can be selectively melted.

  Moreover, according to the separator 1 which concerns on Embodiment 1, since melting | fusing point of the resin which has the heat bondability which comprises the joining nanofiber 22 is 10 degreeC or more lower than melting | fusing point of the material which comprises the base material layer 10, by heating It becomes easy to selectively melt the bonded nanofibers.

  Moreover, according to the separator 1 which concerns on Embodiment 1, since the average diameter of joining nanofiber 22 exists in the range of 50 nm-1000 nm, it joins a base material layer and a nanofiber layer with sufficient intensity, and It becomes possible to suppress that the liquid permeability of a separator falls.

  Further, according to the separator 1 according to the first embodiment, since the thickness of the separator 1 is in the range of 1 μm to 100 μm, the separator has sufficient mechanical strength and has sufficiently low ion resistance. It becomes possible to do.

  Moreover, according to the separator 1 which concerns on Embodiment 1, since the joining nanofiber 22 was obtained by the electrospinning method, desired properties (composition, thickness, basis weight, average diameter of joining nanofiber, melting temperature) It is possible to form a nanofiber layer having solubility in a solvent.

  Since the separator manufacturing apparatus 100 according to the first embodiment includes the electrospinning apparatus 120 and the bonding apparatus 130 that bonds the base material layer 10 and the nanofiber layer 20 using the bonded nanofibers 22, as described above. It becomes possible to manufacture the separator 1 which concerns on an embodiment.

  Moreover, according to the separator manufacturing apparatus which concerns on Embodiment 1, since the joining apparatus 130 consists of a thermobonding apparatus thermocompression-bonded in the state which laminated | stacked the base material layer 10 and nanofiber layer 20 ', it is heat | fever as joining nanofiber. In the case of using bonded nanofibers made of a resin having bonding properties, the base material layer and the nanofiber layer can be bonded by heating.

  According to the separator manufacturing method according to the first embodiment, the base material layer preparation step S1, the electrospinning step S2, and the joining step S3 for joining the base material layer 10 and the nanofiber layer 20 using the joining nanofibers 22; Are included in this order, it is possible to manufacture the separator 1 according to the first embodiment as described above.

  Moreover, according to the separator manufacturing method which concerns on Embodiment 1, joining process S3 is a thermal joining process of thermocompression bonding in the state which laminated | stacked the base material layer 10 and the nanofiber layer 20, Comprising: It joins by the said thermal joining process. When at least a part of the nanofibers 22 is melted and the base material layer 10 and the nanofiber layer 20 are joined by the joining nanofibers 22, the joining nanofibers made of a resin having thermal joining properties are used as the joining nanofibers. In this case, the base material layer and the nanofiber layer can be joined by heating.

[Embodiment 2]
FIG. 6 is a diagram for explaining the separator 2 according to the second embodiment. FIG. 6A is a perspective view of the separator 2 wound around a core material (not shown), FIG. 6B is an enlarged cross-sectional view of the separator 2, and FIG. It is the schematic diagram which expands further and shows the range shown by B of FIG.6 (b).

  The separator 2 according to the second embodiment basically has the same configuration as that of the separator 1 according to the first embodiment, but the configuration of the nanofiber layer is different from that of the separator 1 according to the first embodiment. That is, in the separator 2 according to the second embodiment, as illustrated in FIG. 6, the nanofiber layer 40 further includes high-melting nanofibers 46 made of a material having a melting point higher than that of the resin having thermal bondability. . In addition, what is shown with the code | symbol 42 in FIG.6 (c) is a joining nanofiber, and has the structure similar to the joining nanofiber 22 in Embodiment 1. FIG.

  As the material of the high melting point nanofiber 46, various materials can be used as long as the material has a melting point higher than that of the resin having thermal bondability. For example, polyvinylidene fluoride (PVDF), polylactic acid (PLA) ), Polypropylene (PP), polyethylene (PE), polyvinyl acetate (PVAc), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyamide (PA), polyurethane (PUR), polyvinyl Alcohol (PVA), polyacrylonitrile (PAN), polyimide (PI), polyetherimide (PEI), polycaprolactone (PCL), polylactic glycolic acid (PLGA), silk, cellulose, chitosan and the like can be used.

  As described above, in the separator 2 according to the second embodiment, the configuration of the nanofiber layer is different from that of the separator 1 according to the first embodiment, but the base material layer 10 is similar to the case of the separator 1 according to the first embodiment. Since it has the nanofiber layer 40 containing at least the joining nanofiber 42 used for joining with the separator, it is possible to suppress the liquid permeability of the separator from being lowered, and the electrolyte absorption is higher than that of the conventional separator. Performance and lower ionic resistance can be realized.

  Moreover, according to the separator 2 which concerns on Embodiment 2, since the nanofiber layer 40 further contains the high melting point nanofiber 46 which consists of material which has melting | fusing point higher than melting | fusing point of the resin which has heat bondability, the average diameter of a fiber It is possible to prevent the structure of the nanofiber layer having fine pores from being broken.

  In addition, since the separator 2 which concerns on Embodiment 2 has the structure similar to the separator 1 which concerns on Embodiment 1 except the structure of a nanofiber layer, the applicable effect is the same as the effect which the separator 1 which concerns on Embodiment 1 has. Have.

  As mentioned above, although this invention was demonstrated based on said embodiment, this invention is not limited to said embodiment. The present invention can be implemented in various forms without departing from the spirit thereof, and for example, the following modifications are possible.

(1) The number, positional relationship, and size of each component in each of the above embodiments are examples, and the present invention is not limited to this.

(2) In each of the above embodiments, the separator of the present invention has been described by taking the separator composed of the base material layer 10 and the nanofiber layer as an example, but the present invention is not limited to this. For example, it is good also as a separator further provided with components (reinforcing member etc.) other than a base material layer and a nanofiber layer.

(3) Although the separator 1 which concerns on the said Embodiment 1 shall be manufactured using the separator manufacturing apparatus 100 which concerns on embodiment, this invention is not limited to this. For example, the separator of the present invention may be manufactured using a separator manufacturing apparatus in which the electrospinning apparatus and the bonding apparatus are separate bodies. Thus, the separator of this invention can be manufactured using various separator manufacturing apparatuses.

(4) Although the separator 1 according to Embodiment 1 is manufactured by the separator manufacturing method according to the embodiment, the present invention is not limited to this. For example, the separator of the present invention may be manufactured by a separator manufacturing method in which a step of manufacturing a base material layer and an electrospinning step are performed simultaneously. Thus, the separator of the present invention can be manufactured using various separator manufacturing methods.

(5) Although the separator manufacturing method according to Embodiment 1 is performed using the separator manufacturing apparatus 100, the present invention is not limited to this. For example, the separator manufacturing method of the present invention may be performed using a separator manufacturing apparatus in which the electrospinning apparatus and the joining apparatus are separate from each other. Thus, the separator manufacturing method of the present invention can be performed using various separator manufacturing apparatuses.

(6) In each of the above embodiments, bonded nanofibers made of a resin having thermal bondability are used, and the base material layer 10 and the nanofiber layer are bonded by bonded nanofibers that are at least partially melted by heat. Although the present invention has been described by taking a separator as an example, the separator of the present invention is not limited to this. FIG. 7 is a flowchart of a separator manufacturing method according to a modification. For example, a separator in which bonded nanofibers made of a resin that is soluble in a predetermined solvent are used, and at least a part of the base material layer and the nanofiber layer are bonded by bonded nanofibers dissolved in a predetermined solvent. It is good. For example, as shown in FIG. 7, such a separator is formed by immersing the nanofiber laminate in a solvent having appropriate solubility with respect to the bonded nanofibers, or through the nanofiber laminate in the vapor of the solvent. It can manufacture by performing joining process (melting joining process) S3 'which joins a nanofiber layer. By setting it as such a structure, it becomes possible to join a base material layer and a nanofiber layer easily using a predetermined solvent.

(7) In the case of (6) above, the nanofiber layer is made of a material having a low solubility made of a material having lower solubility in a predetermined solvent than a resin having solubility in the predetermined solvent. It is preferable that a fiber is further included. By setting it as such a structure, it becomes possible to suppress that the structure of the nanofiber layer that the average diameter and the space | gap of a fiber are fine breaks.

(8) In the first embodiment, the present invention has been described by taking the separator manufacturing apparatus 100 including one electrospinning apparatus 120 as an example, but the present invention is not limited to this. For example, a separator manufacturing apparatus including two or more electrospinning apparatuses can be applied to the present invention.

DESCRIPTION OF SYMBOLS 1, 2 ... Separator, 10 ... Base material layer, 12 ... Base material fiber, 20, 40 ... Nano fiber layer (after joining process), 20 '... Nano fiber layer (before joining process), 22, 42 ... Joining Nanofiber, 24, 44 ... Molten bonded nanofiber, 30 ... Nanofiber laminate, 46 ... High melting point nanofiber, 100 ... Separator manufacturing device, 110 ... Conveyor device, 111 ... Feeding roller, 112 ... Winding roller, 113 , 118 ... tension roller, 114 ... auxiliary roller, 120 ... electrospinning device, 130 ... bonding device, 200 ... housing, 210 ... nozzle unit, 220 ... upward nozzle, 250 ... collector, 252 ... insulator, 260 ... power supply device 270 ... Auxiliary belt device, 272 ... Auxiliary belt, 274 ... Auxiliary belt roller

Claims (14)

A base material layer;
A nanofiber layer including at least bonded nanofibers used for bonding with the base material layer;
The said base material layer and the said nanofiber layer are joined by the said joint nanofiber, The separator characterized by the above-mentioned. The separator according to claim 1, wherein
The bonded nanofiber is made of a resin having thermal bondability,
The separator is characterized in that the base material layer and the nanofiber layer are bonded by bonded nanofibers at least partially melted by heat. The separator according to claim 2,
The separator characterized by the melting point of the resin having thermal bondability constituting the bonding nanofiber being lower than the melting point of the material constituting the base material layer. The separator according to claim 3,
The separator characterized by having a melting point of the resin having the heat bonding property constituting the bonding nanofiber is lower by 10 ° C. or more than the melting point of the material forming the base material layer. In the separator in any one of Claims 2-4,
An average diameter of the bonded nanofiber is in a range of 50 nm to 1000 nm. In the separator according to any one of claims 2 to 5,
The nanofiber layer further includes a high-melting-point nanofiber made of a material having a melting point higher than that of the resin having thermal bondability. The separator according to claim 1, wherein
The bonding nanofiber is made of a resin having solubility in a predetermined solvent,
The separator is characterized in that the base material layer and the nanofiber layer are bonded at least partially by bonded nanofibers dissolved in the predetermined solvent. The separator according to claim 7,
The nanofiber layer further includes a low-solubility nanofiber made of a material having lower solubility in the predetermined solvent than a resin having solubility in the predetermined solvent. In the separator according to any one of claims 1 to 8,
The separator has a thickness in the range of 1 μm to 100 μm. In the separator according to any one of claims 1 to 9,
The bonded nanofiber is obtained by an electrospinning method. An electrospinning apparatus that forms a nanofiber layered product by forming a nanofiber layer containing bonded nanofibers on one surface of the base material layer by an electrospinning method;
A separator manufacturing apparatus comprising: a bonding device that bonds the base material layer and the nanofiber layer using the bonded nanofibers in the nanofiber laminate. In the separator manufacturing apparatus according to claim 11,
The said joining apparatus consists of a thermal joining apparatus thermocompression-bonded in the state which laminated | stacked the said base material layer and the said nanofiber layer, The separator manufacturing apparatus characterized by the above-mentioned. A base material layer preparation step of preparing a base material layer;
An electrospinning process in which a nanofiber layer including bonded nanofibers is formed on one surface of the base material layer by an electrospinning method to form a nanofiber laminate;
The separator manufacturing method characterized by including the joining process which joins the said base material layer and the said nanofiber layer using the said joining nanofiber in the said nanofiber laminated body in this order. In the separator manufacturing method according to claim 13,
The bonding step is a heat bonding step of thermocompression bonding in a state where the base material layer and the nanofiber layer are laminated, and at least a part of the bonding nanofibers is melted by the heat bonding step. A separator and a nanofiber layer are bonded to each other with the bonded nanofiber.

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