Porous film laminate manufacturing apparatus and manufacturing method

Abstract

Provided is a porous film laminate manufacturing apparatus that solves a trade-off between bondability and porosity. This porous film laminate manufacturing apparatus is used for manufacturing a porous film laminate in which a first porous film and a second porous film are superimposed, the porous film laminate manufacturing apparatus comprising a porous film overlapping part in which the first porous film and the second porous film are superimposed and which constitutes the porous film laminate, a liquid agent spraying / coating part that sprays or applies a liquid agent to the surface of the first porous film on the side opposite from the bonding surface between the first porous film and the second porous film, and a pressurizing part that pressurizes the porous film laminate.

Description

Porous membrane laminate manufacturing apparatus and manufacturing method

[0001] The present disclosure relates to an apparatus for manufacturing a porous membrane stack and a method for manufacturing the same.

[0002] Global warming is one of the most serious environmental problems in recent years. The modernization and rapid economic development of emerging countries, the further economic growth of developed countries, and the increase in international trade have led to a significant increase in the use of fossil fuels, resulting in CO2 emissions. ２ Emissions continue to increase. To solve this problem, there are high hopes for the development of clean, fossil-fuel-free power generation methods, which are rapidly gaining attention.

[0003] The manufacturing process for porous laminates used in electrochemical devices such as batteries, capacitors, and fuel cells involves multiple membrane bonding steps. Generally, membrane-to-membrane bonding can be broadly divided into three types. First, mechanical bonding. This is also known as the anchor effect, in which the membranes or adhesive penetrate into the pores or irregularities on the surfaces of the materials to be bonded, creating a physical bond. Second, chemical interaction. This bonding principle utilizes a chemical bonding force similar to a covalent bond, which occurs when atoms in two materials share electrons. Third, physical interaction. This is known as intermolecular force or van der Waals force, and is a bonding principle that utilizes the molecular attraction between two materials when the distance between them is very short. Other commonly used methods for joining metals include arc welding and laser welding. In particular, when joining porous membranes made of carbon materials, the interaction between atoms and molecules within the membranes is weak, making mechanical bonding necessary.

[0004] Representative examples of bonding steps in conventional porous membrane laminate manufacturing processes include (1) bonding using an adhesive, (2) pressure lamination using a hot press, (3) forming a laminate structure by coating on a porous membrane, and (4) joining membrane edges by ultrasonic welding. For example, in Patent Document 1, a porous membrane laminate for a fuel cell is formed by pressure lamination using a hot press. A method of forming a porous membrane laminate by spray coating on one membrane is also used.

[0005] JP 2010-198762 A

[0006] In the process of bonding two porous membranes, bonding them by applying pressure while maintaining the membrane's porosity creates a trade-off between bonding and porosity. If the applied pressure is too low, the membranes cannot be bonded, while if the applied pressure is too high, the membranes lose their porosity. Therefore, a porous membrane bonding technique that can be applied with low load is required.

[0007] An object of the present disclosure is to provide a porous membrane laminate manufacturing apparatus that resolves the trade-off between bondability and porosity.

[0008] In order to achieve the above-mentioned object, the porous membrane laminate manufacturing apparatus according to the present disclosure is a porous membrane laminate manufacturing apparatus for manufacturing a porous membrane laminate in which a first porous membrane and a second porous membrane are superimposed, and is equipped with a porous membrane superimposing unit that superimposes the first porous membrane and the second porous membrane to form the porous membrane laminate, a liquid agent spraying / application unit that sprays or applies a liquid agent to the surface of the first porous membrane opposite to the joining surface between the first porous membrane and the second porous membrane, and a pressurizing unit that pressurizes the porous membrane laminate.

[0009] The porous membrane stack manufacturing method according to the present disclosure includes the steps of: overlapping a first porous membrane and a second porous membrane to form a porous membrane stack; spraying or applying a liquid agent to the surface of the first porous membrane opposite to the joining surface between the first porous membrane and the second porous membrane; and pressurizing the porous membrane stack.

[0010] The porous membrane stack manufacturing apparatus according to the present disclosure makes it possible to bond multiple porous membranes with a low load.

[0011] 1 is a schematic diagram showing the general configuration of a porous membrane laminate manufacturing apparatus according to Embodiment 1. FIG. 1 is a schematic diagram showing the general configuration of a porous membrane laminate manufacturing apparatus according to Modification 1 (when both porous membranes A and B are single membranes). FIG. 2 is a schematic diagram showing the general configuration of a porous membrane laminate manufacturing apparatus according to Modification 2 (when spraying from vertically below to vertically above). FIG. 3 is a schematic diagram showing the general configuration of a porous membrane laminate manufacturing apparatus according to Modification 3 (when liquid agent is sprayed before porous membranes are superimposed). FIG. 4 is a schematic diagram showing the general configuration of a porous membrane laminate manufacturing apparatus according to Modification 4 (when producing single wafers). FIG. 1 is a schematic perspective view showing the state of a liquid agent sprayed from a nozzle of a liquid agent spraying / application unit of the porous membrane laminate manufacturing apparatus of FIG. 1 is a flowchart of a method for manufacturing a porous membrane laminate according to Embodiment 1.

[0012] <Background to the present disclosure> As described above, bonding by pressure while maintaining the porosity of the membranes creates a trade-off between bonding and porosity. The present inventors came up with the idea of ​​addressing this trade-off by providing a liquid agent at the bonding interface, enabling porous membrane lamination at low loads without the use of adhesive. Meanwhile, when a porous membrane laminate is used, for example, as a gas diffusion layer in a fuel cell, the porous membrane may contain a catalytic material such as platinum. In such cases, the catalytic material may promote the oxidation reaction of the sprayed or applied liquid agent, potentially causing the porous membrane to burn. The present inventors then realized the problem of the impossibility of directly spraying or applying a liquid agent to the bonding interface of the porous membrane.

[0013] The present inventors have conducted extensive research into the above-mentioned problems and have come up with the idea of ​​spraying or applying a liquid agent to the surface of the first porous film on the side opposite to the bonding interface between the first and second porous films. This has led to the discovery that, even when the second porous film contains a catalyst material, it is possible to allow the liquid agent to reach the bonding interface between the first and second porous films while avoiding the catalyst material from promoting oxidation of the liquid agent. This has led to the present disclosure.

[0014] Each aspect of the present disclosure will be described below.

[0015] The porous membrane laminate manufacturing apparatus according to the first aspect is a porous membrane laminate manufacturing apparatus for manufacturing a porous membrane laminate in which a first porous membrane and a second porous membrane are overlapped, and includes a porous membrane overlapping unit that overlaps the first porous membrane and the second porous membrane to form the porous membrane laminate, a liquid agent spraying / application unit that sprays or applies a liquid agent to the surface of the first porous membrane opposite to the joining surface between the first porous membrane and the second porous membrane, and a pressurizing unit that pressurizes the porous membrane laminate.

[0016] The porous membrane stack manufacturing apparatus according to the second aspect may further include, in the above-mentioned first aspect, a porous membrane unwinding section that unwinds the first and second porous membranes, and a porous membrane stack winding section that winds up the superposed porous membrane stack.

[0017] The porous membrane stack manufacturing apparatus according to the third aspect may be the first or second aspect, wherein the first porous membrane and the second porous membrane are each continuous in the longitudinal direction, and the first porous membrane and the second porous membrane can be continuously superimposed on each other.

[0018] The porous membrane stack manufacturing apparatus according to the fourth aspect is the porous membrane stack manufacturing apparatus according to claim 1, wherein in the first or second aspect, the first porous membrane and the second porous membrane are each a single sheet, and the first porous membrane and the second porous membrane can be stacked one on top of the other in a single sheet.

[0019] The porous membrane stack manufacturing apparatus according to the fifth aspect is any one of the first to fourth aspects, wherein the first porous membrane may be a single membrane or a porous membrane formed on a substrate.

[0020] The porous membrane stack manufacturing apparatus according to a sixth aspect is the apparatus of any one of the first to fifth aspects, wherein the conveying flatness of the porous membrane may be set to within 1.0 mm.

[0021] The porous membrane stack manufacturing apparatus according to the seventh aspect may be any of the first to sixth aspects, in which the liquid agent spraying / application section is installed vertically below the first porous membrane, and the liquid agent may be sprayed or applied to the first porous membrane from vertically below to vertically above.

[0022] The porous membrane laminate manufacturing apparatus according to the eighth aspect is any one of the first to seventh aspects, wherein the liquid agent spraying / application unit may have a tension application unit that applies tension to the porous membrane laminate while spraying or applying the liquid agent.

[0023] The method for manufacturing a porous membrane stack according to the ninth aspect includes the steps of: overlapping a first porous membrane and a second porous membrane to form a porous membrane stack; spraying or applying a liquid agent to the surface of the first porous membrane opposite to the joining surface between the first porous membrane and the second porous membrane; and pressurizing the porous membrane stack.

[0024] A tenth aspect of the porous membrane stack manufacturing method is the same as the ninth aspect, except that the step of spraying or applying the liquid agent may be performed after the step of overlapping the first porous membrane and the second porous membrane.

[0025] In the method for manufacturing a porous membrane stack according to an eleventh aspect, in the above-mentioned ninth aspect, the step of spraying or applying the liquid agent may be performed before the step of overlapping the first porous membrane and the second porous membrane.

[0026] The porous membrane stack manufacturing method according to the twelfth aspect may further include, in any one of the ninth to eleventh aspects, the steps of unwinding the first porous membrane and the second porous membrane, and winding up the pressure-bonded porous membrane stack.

[0027] The method for manufacturing a porous membrane stack according to a thirteenth aspect may be any of the ninth to twelfth aspects, in which the first porous membrane and the second porous membrane are continuously pressurized in the step of pressurizing the porous membrane stack.

[0028] The porous membrane stack manufacturing method according to a fourteenth aspect is any one of the ninth to twelfth aspects, wherein in the step of pressurizing the porous membrane stack, the first porous membrane and the second porous membrane may be pressed one by one.

[0029] A porous membrane stack manufacturing method according to a fifteenth aspect is any one of the ninth to fourteenth aspects, wherein an organic solvent may be used as the liquid agent in the step of spraying or applying the liquid agent.

[0030] The porous membrane stack manufacturing method according to the sixteenth aspect may be any of the ninth to fifteenth aspects, wherein tension is applied to the porous membrane stack during the step of spraying or applying the liquid agent.

[0031] The porous membrane laminate manufacturing method according to the seventeenth aspect may be any of the ninth to sixteenth aspects, wherein in the step of spraying or applying a liquid agent, the transport flatness of the porous membrane laminate in the sprayed or applied area of ​​the liquid agent may be within 1.0 mm.

[0032] The porous membrane stack manufacturing method according to an eighteenth aspect may be any of the ninth to seventeenth aspects, in which the liquid agent is sprayed from vertically below to vertically above in the step of spraying or applying the liquid agent.

[0033] The porous membrane stack manufacturing method according to a nineteenth aspect is any one of the ninth to eighteenth aspects, wherein in the pressurizing step, the surface of the porous membrane stack may be pressed in a state where it is covered with a sheet.

[0034] The porous membrane stack manufacturing method according to the twentieth aspect is any one of the ninth to nineteenth aspects, wherein at least one of the first porous membrane and the second porous membrane may be a single membrane.

[0035] Hereinafter, a porous membrane stack manufacturing apparatus and manufacturing method according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0036] (Embodiment 1) FIG. 1 is a schematic diagram showing the overall configuration of a porous membrane laminate manufacturing apparatus 1 according to embodiment 1. This porous membrane laminate manufacturing apparatus 1 includes at least a porous membrane superposition unit 3, a liquid agent spraying / application unit 4, and a pressurizing unit 5. A first porous membrane and a second porous membrane are superposed in the porous membrane superposition unit 3 to form a porous membrane laminate. Pretreatment for bonding is performed in the liquid agent spraying / application unit 4. The two porous membranes are pressed together by a bonding roll 19 in the pressurizing unit 5. This porous membrane laminate manufacturing apparatus 1 can manufacture porous membrane laminates by including the above components. Furthermore, by using the porous membrane unwinding unit 2 and the porous membrane laminate winding unit 6, the porous membrane laminate manufacturing apparatus according to embodiment 1 can continuously manufacture porous membrane laminates. Porous membrane laminates manufactured by the porous membrane laminate manufacturing apparatus according to embodiment 1 can be used, for example, in lithium-ion batteries, fuel cells, and all-solid-state batteries.

[0037] Each of the components constituting this porous membrane laminate manufacturing apparatus will be described below.

[0038] The porous membrane laminate manufacturing apparatus 1 is composed of a porous membrane unwinding section 2, a porous membrane overlapping section 3, a liquid agent spraying / application section 4, a pressure applying section 5, and a porous membrane laminate winding section 6. Hereinafter, the two porous membranes to be joined will be referred to as porous membrane A (first porous membrane) and porous membrane B (second porous membrane).

[0039] <Porous membrane unwinding section> The porous membrane unwinding section 2 is composed of an unwinding roll 8 for unwinding porous membrane A and an unwinding roll 11 for unwinding porous membrane B. In addition, in FIG. 1, porous membrane A is a single membrane, and porous membrane B is a membrane coated on a substrate 10, but this is not limited to this. In FIG. 1, porous membrane A (7), porous membrane B (9), and substrate 10 appear discontinuous, but this is due to a simplified description. In reality, porous membrane A (7), porous membrane B (9), and substrate 10 are all continuously connected in the longitudinal direction. The same applies to the following FIGS. 2 to 4. In FIG. 5, porous membrane A (7) and porous membrane B (9) are sheets, and substrate 10 is continuously connected in the longitudinal direction. Two types of porous membranes A and B to be joined are set on unwinding rolls 8 and 11, respectively, and the unwinding rolls rotate while applying tension, allowing porous membranes A and B to be continuously unwound. The unwinding rolls 8 and 11 are made of, but not limited to, ABS material. The substrate 10 is preferably made of, but not limited to, a film of, for example, PTFE, polypropylene (PP), polyethylene terephthalate (PET), polyimide, or the like.

[0040] (Modification 1) Fig. 2 is a schematic diagram showing the schematic configuration of a porous membrane laminate manufacturing apparatus 1a according to Modification 1 (when both porous membranes A and B are single membranes). As shown in Fig. 2, both porous membranes A and B may be single membranes that are made of only porous membranes and do not have a substrate.

[0041] <Porous membrane superposition unit> The porous membrane superposition unit 3 has the role of superposing the porous membrane A and the porous membrane B, and is configured to be superposed on the transport roll. In order to improve the superposition accuracy, it is preferable that an EPC (Edge Position Control) mechanism is provided downstream of each porous membrane unwinding process, which controls the position of the edge of the porous membrane in the width direction to be constant. In addition, it is preferable that a dancer roll mechanism is provided to reduce the slack of the membrane during transport.

[0042] <Liquid Agent Spraying / Coating Section> Figure 6 is a schematic perspective view showing the state of the liquid agent 15 sprayed from the nozzle 14 of the liquid agent spraying / coating section 4 of the porous membrane laminate manufacturing apparatus 1 of Figure 1. The liquid agent spraying / coating section 4 is composed of a backup roll 12, nip rolls 13, a nozzle 14 for spraying or coating the liquid agent 15, and a spray cover 16 for preventing the sprayed liquid agent 15 from scattering. The backup roll 12 tensions the porous membrane on the backup roll 12, thereby eliminating slack during transport and enabling precise control of the amount of liquid agent 15 sprayed or coated onto the porous membrane A. The nip rolls 13 serve to support the porous membranes A and B when spraying or coating the liquid agent onto them, preventing them from being blown away by the pressure during spraying or coating. The load applied by the nip rolls 13 is, for example, 1 kg, but is not limited thereto.

[0043] Furthermore, the nip roll 13 is a free roll, but may be driven. Furthermore, while a rubber material is used for the nip roll 13, this is not a limitation. The nozzle 14 for spraying or applying the liquid agent may be, for example, an SV-6 spray nozzle manufactured by Musashi Engineering, Inc. The nozzle position (height) may be set so that the height from the porous membrane A7 can be set within a range of 10 to 1,000 mm, and multiple nozzles 14 may be installed in the width direction. Alternatively, as shown in FIG. 6 , the liquid agent 15 may be sprayed from a single nozzle 14 onto the surface of the porous membrane A7 so as to be dispersed in both the longitudinal and width directions. The liquid agent 15 passes through the pores from the surface of the porous membrane A7 and reaches the interface with the porous membrane B9.

[0044] Furthermore, in order to uniformly distribute the liquid agent within the surface, the conveying flatness of the porous membrane A is set to within 1.0 mm. The conveying flatness can be calculated by the value of the gap that occurs when the target surface is sandwiched between parallel planes. The conveying flatness is measured using a non-contact measurement method using a laser. For example, flatness can be measured by irradiating the target with a band-shaped laser beam, forming an image of the reflected light, and measuring the intensity of the imaged reflected light. Furthermore, during liquid agent spraying, the liquid agent spraying / applying unit 4 sprays the liquid agent onto the porous membrane A from the surface opposite the bonding surface of at least one porous membrane. The liquid agent 15 sprayed onto the surface of the porous membrane A passes through the pores of the porous membrane A and reaches the interface between the porous membrane A and the porous membrane B. The liquid agent to be sprayed is preferably, but not limited to, an organic solvent such as ethanol or propanol. In addition, the liquid agent spraying / application unit 4 may be provided with a suction unit on the back side, for example, within the bonding roll 20, to create negative pressure so that the sprayed or applied liquid agent 15 can easily pass through the pores of the porous membrane A.

[0045] <Pressure Unit> The pressure unit 5 is composed of a cover film 17, an unwinding roll 18 for the cover film 17, a winding roll 19 for the cover film 17, a joining roll 20, and a nip roll 13. In this embodiment, a heating roll mechanism is used as the pressure unit, but the present invention is not limited to this.

[0046] The cover film 17 serves to seal the liquid agent 15 sprayed or applied by the liquid agent spraying / application unit 4 so that it does not escape into the atmosphere. Furthermore, sealing the film reduces the oxygen concentration within the film, thereby reducing the reactivity between the liquid agent 15 and the porous membrane B. In particular, if the porous membrane contains a catalytic material such as platinum, this may promote the oxidation reaction of the sprayed or applied liquid agent, potentially causing the porous membrane to burn. In such cases, sealing with the cover film 17 as described above reduces the oxygen concentration and inhibits the oxidation reaction of the liquid agent. Furthermore, it is possible to prevent the porous membrane A from directly contacting the bonding roll 20. Because the cover film is required to have film strength and thermal conductivity, it is desirable to use, for example, a polyimide film.

[0047] The bonding roll 20 serves to pressure-bond porous membranes A and B while maintaining their porosity. At this time, the presence of liquid agent 15 at the interface between porous membranes A and B allows the two porous membranes to be bonded using the anchor effect. This is due to the porous membrane B's ability to easily disperse liquid agent 15. By dispersing liquid agent 15 on the surface of porous membrane B, the outermost surface of porous membrane B temporarily softens. When pressure is applied at this time, the interface between porous membranes A and B physically engages, allowing porous membranes A and B to be bonded. The bonding roll 20 may be capable of controlling the load to within approximately ±1%, for example, allowing for precise bonding conditions. The diameter of the bonding roll 20 may also be adjustable from 50 to 200 mm. This allows for settings tailored to the conditions of the porous membranes to be pressure-bonded. The bonding roll 20 may contain an electric heater. The inclusion of an electric heater enables it to be used as a heated roll. In this example, the upper roll of the joining rolls 20 is driven up and down to change the gap between the rolls, but the lower roll may also be driven.

[0048] (Modification 2) Fig. 3 is a schematic diagram showing the outline configuration of a porous membrane laminate manufacturing apparatus 1b according to Modification 2 (in the case of spraying from vertically below to vertically above). As shown in Fig. 3, the liquid agent spraying / application unit 4 and the pressurizing unit 5 may be located vertically below the porous membranes A and B, and the liquid agent may be sprayed and heated from vertically below to vertically above the evaporation direction.

[0049] <Porous Membrane Stack Winding Section> The porous membrane stack winding section 6 may include a winding roll 22 for winding the porous membrane stack 21 pressure-bonded in the previous process. The porous membrane stack 21 includes bonded porous membranes A and B. Furthermore, since porous membrane B is coated on the substrate 10, the porous membrane stack 21 has a three-layer laminate structure of porous membrane A, porous membrane B, and substrate 10. The tension required for winding is applied to the substrate 10 to perform winding. To improve winding accuracy in the width direction, an EPC mechanism is preferably provided in the process preceding the winding roll 22. Furthermore, as with the porous membrane unwinding section 2 and the porous membrane overlapping section 3, a dancer roll mechanism is preferably provided to reduce membrane slack during transport. While the porous membrane stack winding roll 22 is made of an ABS material, the material is not limited thereto.

[0050] It should be noted that any of the various embodiments or modifications described above can be combined appropriately to achieve the effects of each. In addition, combinations of embodiments, combinations of examples, or combinations of embodiments and examples are possible, and combinations of features of different embodiments or examples are also possible.

[0051] <Method for Manufacturing a Porous Membrane Stack> FIG. 7 is a flowchart of a method for manufacturing a porous membrane stack according to the first embodiment. The method for manufacturing a porous membrane stack according to the first embodiment can be performed, for example, using the porous membrane stack manufacturing apparatus described above. This method for manufacturing a porous membrane stack includes at least the following steps: (1) A first porous membrane and a second porous membrane are stacked to form a porous membrane stack (S01). When using the porous membrane stack manufacturing apparatus described above, porous membranes A and B are set in the porous membrane unwinding section 2 and then stacked in the porous membrane stacking section 3. (2) A liquid agent is sprayed or applied to the surface of the first porous membrane opposite the joining surface between the first and second porous membranes (S02). When using the porous membrane stack manufacturing apparatus described above, a liquid agent is sprayed using the liquid agent spraying / applying section 4. This corresponds to pre-treatment for joining. (3) The porous membrane stack is pressurized (S03). When the porous membrane laminate manufacturing apparatus is used, the porous membrane A and the porous membrane B are pressure-bonded by applying pressure while heating in the pressure unit 5, thereby obtaining the porous membrane laminate 21. Furthermore, when the porous membrane laminate manufacturing apparatus is used, the following step of recovering the porous membrane laminate 21 by the porous membrane laminate winding unit 6 may be included. (4) The porous membrane laminate 21 is wound up by the porous membrane laminate winding unit 6 and recovered.

[0052] This manufacturing method will be described in detail below, following each of the steps actually performed.

[0053] (1) First, the process of stacking the first and second porous membranes will be described. When using the porous membrane laminate manufacturing apparatus described above, porous membranes A and B are first set in the unwinding section. Here, porous membranes A and B are primarily made of carbon materials, but are not limited to this. The porous membrane used is an electrode membrane for a fuel cell. Porous membrane A is a gas diffusion layer, and porous membrane B is a catalyst layer. The reactivity of porous membrane B with the liquid agent (ethanol) used is very high, and direct spraying or application of the liquid agent onto porous membrane B is not possible due to the risk of fire. This is because the catalyst layer contains a catalytic material such as platinum, which promotes the oxidation reaction of the sprayed or applied liquid agent and may cause the porous membrane to burn. Here, porous membrane A is a single membrane, and porous membrane B is a membrane coated on a substrate. Porous membrane A may be set on porous membrane A unwinding roll 8 and unwound under tension. At this time, the tension may be, for example, in the range of 0.5 to 1,000 N, but is not limited thereto. As with the porous membrane A, the porous membrane B coated on the substrate 10 is set on the porous membrane unwinding roll 11, and the substrate 10 is unwound by applying tension. At this time, the tension may be, for example, in the range of 1 to 1,000 N, but is not limited thereto. The unwound porous membranes A and B are then superposed in the porous membrane superposing section 3.

[0054] (2) Next, the process of performing pretreatment for bonding in the liquid agent spraying / application unit 4 will be described. The liquid agent 15 serves as an adhesive for bonding porous membranes A and B. Generally, bonding of porous membranes is achieved by applying an adhesive to the interface between the porous membranes. However, since the porous membrane laminate in this embodiment is used as an electrode material for a fuel cell, there is a problem in that the pores in the porous membrane must not be filled with adhesive. Therefore, highly volatile ethanol is used as an adhesive substitute, and by applying heat and pressure in a subsequent process, the ethanol evaporates, making it possible to form a porous membrane laminate without crushing the pores in the porous membrane. The porous membranes A and B and the substrate 10 flowing from the previous process are nipped by nip rolls 13 and stretched by backup rolls 12. The nip load may be, for example, 1 kgf. In this state, the liquid agent 15 is sprayed or applied from a nozzle 14. Ethanol is selected as the liquid agent to be sprayed, and the ethanol is supplied by a spray method, with a spray amount of 0.1 to 10 mg / cm. ２ The liquid agent may be other solvents, solvents, organic solvents, etc. The method of supplying the solvent 15 is not limited to the spray method, and a coating method may also be used. Furthermore, as in Modification 2 of FIG. 3, the liquid agent may be sprayed onto the porous membrane from vertically below the manufacturing apparatus.

[0055] (Variation 3) Fig. 4 is a schematic diagram showing the general configuration of a porous membrane laminate manufacturing apparatus 1c according to Variation 3 (in the case of spraying a liquid agent before superposing the porous membranes). As shown in Fig. 4, the step of spraying or applying a liquid agent may be carried out before the step of superposing the porous membranes. In this case, in the porous membrane laminate manufacturing apparatus 1c, the liquid agent spraying / application unit 4 is arranged upstream of the porous membrane superposing unit 3.

[0056] (3) Next, the process of bonding porous membranes A and B by applying pressure while heating in the pressure unit 5 will be described. To maintain the amount of liquid agent 15 sprayed in the previous process without evaporating it, for example, a cover film 17 may be immediately applied to seal the membrane after spraying. A tension of 10 to 100 N may be applied to the cover film during unwinding and rewinding. After the cover film 17 is applied, the porous membranes A and B are bonded using the bonding roll 20. At this time, heating may be performed using the bonding roll 20 to vaporize the sprayed liquid agent 15. The heating temperature may be set to, for example, 100°C. In this case, the heating temperature may be set to a temperature equal to or lower than the heat resistance temperature of the substrate 10. Furthermore, if the heating temperature is equal to or higher than the boiling point of the liquid agent 15, the liquid agent can be easily vaporized. By vaporizing the liquid agent, it is possible to prevent the liquid agent 15 from reacting excessively with the porous membrane B and causing deterioration of the membrane when the reactivity between the liquid agent 15 and the porous membrane B is high. The liquid agent 15 is sprayed from the upper surface of the porous membrane A and vaporized by heating, and the vapor of the sprayed liquid agent passes through the micropores inside the porous membrane A and reaches the interface between the porous membranes A and B. This eliminates the need to spray the liquid agent on the surface of the porous membrane B, and the liquid agent can be guided to the bonding interface between the porous membranes A and B by utilizing the porous membrane's ability to control the amount of liquid agent in minute amounts. The load for bonding may be, for example, 500 kgf. By spraying the liquid agent 15, it becomes possible to bond two porous membranes without using an adhesive.

[0057] (4) Next, the process of winding and recovering the porous membrane laminate 21 by the porous membrane laminate winding unit 6 will be described. The porous membranes A and B joined in the previous process form the porous membrane laminate 21 having a three-layer structure of porous membrane A, porous membrane B, and substrate 10. The winding roll 22 for the porous membrane laminate 21 applies a tension of 10 to 50 N to the substrate 10 to perform winding and recovery. Furthermore, in this embodiment, all processes of the equipment are carried out by setting the conveying speed to, for example, 1 to 10 m / min, making it possible to continuously produce porous membrane laminates.

[0058] Furthermore, although a continuous porous membrane laminate manufacturing method is carried out in this embodiment, a single-wafer porous membrane laminate manufacturing method may also be used.

[0059] (Modification 4) Fig. 5 is a schematic diagram showing the outline configuration of a porous membrane laminate manufacturing apparatus 1d according to Modification 4 (in the case of single-wafer manufacturing). As shown in Fig. 5, when carrying out the single-wafer porous membrane laminate manufacturing method, porous membrane A is superimposed on porous membrane B, and the steps of liquid agent spraying, pressure bonding, and winding are carried out in the same manner as in continuous manufacturing.

[0060] The porous membrane laminate manufacturing apparatus and the porous membrane laminate manufacturing method according to the present disclosure can bond two porous membranes while maintaining porosity without using adhesive, thereby manufacturing a porous membrane laminate.Therefore, the porous membrane laminate manufacturing apparatus and the porous membrane laminate manufacturing method according to the present disclosure are useful as a manufacturing equipment and a manufacturing method for a porous membrane used in clean, fossil fuel-free lithium ion batteries, fuel cells, all-solid-state batteries, etc.

[0061] DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c, 1d Porous membrane laminate manufacturing apparatus 2 Porous membrane unwinding section 3 Porous membrane overlapping section 4 Liquid agent spraying / application section 5 Pressurizing section 6 Porous membrane laminate winding section 7 Porous membrane A 8 Porous membrane A unwinding roll 9 Porous membrane B 10 Porous membrane B unwinding roll 11 Substrate 12 Backup roll 13 Nip roll 14 Nozzle 15 Liquid agent 16 Spray cover 17 Cover film 18 Cover film unwinding roll 19 Cover film winding roll 20 Pressure roll 21 Porous membrane laminate 22 Porous membrane laminate winding roll

Claims

1. A porous membrane laminate manufacturing apparatus for manufacturing a porous membrane laminate in which a first porous membrane and a second porous membrane are overlapped, the porous membrane laminate manufacturing apparatus comprising: a porous membrane overlapping unit that overlaps the first porous membrane and the second porous membrane to form a porous membrane laminate; a liquid agent spraying / application unit that sprays or applies a liquid agent to the surface of the first porous membrane opposite to the joining surface between the first porous membrane and the second porous membrane; and a pressurizing unit that pressurizes the porous membrane laminate.

2. The porous membrane stack manufacturing apparatus according to claim 1, further comprising: a porous membrane unwinding section that unwinds the first and second porous membranes; and a porous membrane stack winding section that winds up the overlapped porous membrane stack.

3. A porous film stack manufacturing apparatus as described in claim 1, wherein the first porous film and the second porous film are each continuous in the longitudinal direction, and the first porous film and the second porous film can be continuously superimposed on each other.

4. A porous film stack manufacturing apparatus as described in claim 1, wherein the first porous film and the second porous film are each a single sheet, and the first porous film and the second porous film can be stacked one on top of the other in a single sheet state.

5. The porous film laminate manufacturing apparatus according to claim 1, wherein the first porous film is a single film or a porous film formed on a substrate.

6. The porous membrane laminate manufacturing apparatus according to claim 1, wherein the conveying flatness of the porous membrane is set to within 1.0 mm.

7. A porous membrane stack manufacturing apparatus as described in claim 1, wherein the liquid agent spraying / application unit is installed vertically below the first porous membrane and sprays or applies the liquid agent onto the first porous membrane from vertically below to vertically above.

8. The porous membrane laminate manufacturing apparatus according to claim 1, wherein the liquid agent spraying / application unit has a tension applying unit that applies tension to the porous membrane laminate while spraying or applying the liquid agent.

9. A method for manufacturing a porous membrane laminate, comprising: a step of overlapping a first porous membrane and a second porous membrane to form a porous membrane laminate; a step of spraying or applying a liquid agent to the surface of the first porous membrane opposite to the bonding surface between the first porous membrane and the second porous membrane; and a step of pressurizing the porous membrane laminate.

10. A method for manufacturing a porous membrane stack as described in claim 9, wherein the step of spraying or applying the liquid agent is performed after the step of overlapping the first porous membrane and the second porous membrane.

11. A method for manufacturing a porous membrane stack as described in claim 9, wherein the step of spraying or applying the liquid agent is performed before the step of overlapping the first porous membrane and the second porous membrane.

12. The method for manufacturing a porous membrane stack described in claim 9, further comprising the steps of unwinding the first porous membrane and the second porous membrane, and winding up the pressure-bonded porous membrane stack.

13. The method for producing a porous membrane stack according to claim 9, wherein in the step of pressurizing the porous membrane stack, the first porous membrane and the second porous membrane are continuously pressurized.

14. The method for manufacturing a porous membrane stack according to claim 9, wherein in the step of pressing the porous membrane stack, the first porous membrane and the second porous membrane are pressed one by one.

15. The method for producing a porous membrane laminate according to claim 9, wherein an organic solvent is used as the liquid in the step of spraying or applying the liquid.

16. The method for producing a porous membrane laminate according to claim 9, wherein the porous membrane laminate is placed under tension during the step of spraying or applying the liquid agent.

17. A method for manufacturing a porous membrane laminate as described in claim 9, wherein in the step of spraying or applying the liquid agent, the transport flatness of the porous membrane laminate in the sprayed or applied area of ​​the liquid agent is set to within 1.0 mm.

18. The method for producing a porous membrane laminate according to claim 9, wherein in the step of spraying or applying the liquid agent, the liquid agent is sprayed from vertically downward to vertically upward.

19. The method for producing a porous membrane laminate according to claim 9, wherein in the pressurizing step, the surface of the porous membrane laminate is pressed while covered with a sheet.

20. The method for manufacturing a porous membrane stack according to claim 9, wherein at least one of the first porous membrane and the second porous membrane is a single membrane.

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