Substrate for solid electrolyte and solid electrolyte sheet including same

Abstract

To provide a substrate for solid electrolyte, suitable for making a solid electrolyte sheet having a low electric resistance, and a solid electrolyte sheet including the same.SOLUTION: The present invention relates to a substrate for solid electrolyte including a nonwoven fabric, having an elastic recovery of 30 to 99%, and a solid electrolyte sheet having a low electric resistance, which includes the substrate for solid electrolyte and a solid electrolyte.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a support for a solid electrolyte and a solid electrolyte sheet containing the same.

Background Art

[0002] In recent years, with the development of portable devices and the practical application of electric vehicles, there is a need for batteries that are small, lightweight, and have high capacity and high energy density.

[0003] Corresponding lithium-ion secondary batteries are composed of a positive electrode active material, a negative electrode active material, and an electrolyte solution. Aiming at further improving functionality, various improvements have been made with the challenges of extending the service life, increasing the capacity, and increasing the energy density. In addition, the installation of products directly related to human lives in automobiles and the like is also progressing. Along with the improvement of the functionality of the previous batteries, safety and reliability are also required at the same time.

[0004] Among these, the battery currently attracting attention is the all-solid-state battery. In conventional lithium-ion secondary batteries, since an organic electrolyte solution is used as the electrolyte, there is a risk of ignition caused by internal short circuits due to overcharging or over-discharging, and there is also a problem that liquid leakage is likely to occur. On the other hand, all-solid-state batteries use solid electrolytes and are highly superior in terms of safety and reliability. As solid electrolytes, sulfide, oxide-based inorganic electrolytes, and polymer-based organic electrolytes are widely used.

[0005] In order to achieve high energy density and high capacity, which are required characteristics of batteries, thinning, high ion conductivity, and strength are required for handling improvement as a solid electrolyte. For this purpose, a support electrolyte in which a solid electrolyte is coated on a support is used, and a fibrous sheet such as a non-woven fabric is used as the support.

[0006] Patent Document 1 below discloses a solid electrolyte sheet having an aromatic liquid crystal polyester non-woven fabric, and the aromatic liquid crystal polyester non-woven fabric is characterized by having a high porosity for the purpose of being filled with a polymer solid electrolyte.

[0007] Patent Document 2 below discloses a solid electrolyte sheet having a porous base material composed of fibrous materials as a support.

[0008] Also, Patent Document 3 below discloses a solid electrolyte sheet having a non-woven fabric with a specific basis weight and thickness as a support.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0010] However, in Patent Documents 1 to 3 above, the flexibility of the electrolyte sheet interface is not sufficiently considered, and an increase in electrical resistance due to insufficient followability and contact with the electrode interface as an electrolyte sheet has been a problem.

[0011] In view of the above problems, the problem to be solved by the present invention is to provide a support for a solid electrolyte suitable for obtaining an electrolyte sheet with low electrical resistance, and a solid electrolyte sheet including the same.

Means for Solving the Problems

[0012] As a result of intensive studies and repeated experiments to solve the above problems, the inventors of the present application unexpectedly found that the above problems can be solved by the following configuration, and thus completed the present invention. That is, the present invention is as follows. [1]A support for a solid electrolyte containing a nonwoven fabric, characterized in that the elastic recovery rate of the support is 30 to 99%, the support for a solid electrolyte. [2]The support for a solid electrolyte according to [1], wherein the porosity of the support is 30 to 95%. [3]The support for a solid electrolyte according to [1] or [2], wherein the compressibility of the support is 0.1 to 40%. [4]The support for a solid electrolyte according to any one of [1] to [3], wherein the nonwoven fabric contains synthetic fibers. [5]The support for a solid electrolyte according to [4], wherein the synthetic fiber is polyester. [6]The 100 g / m of the support 2 The support for a solid electrolyte according to any one of [1] to [5], wherein the thickness under load is 5 to 200 μm. [7]The support for a solid electrolyte according to any one of [1] to [6], wherein the nonwoven fabric contains fibers having a fiber length of 51 mm or more. [8]The support for a solid electrolyte according to any one of [1] to [7], wherein the basis weight of the support is 5 to 50 g / m 2 . [9]The support for a solid electrolyte according to any one of [1] to [8], wherein the nonwoven fabric contains ultrafine fibers having a fiber diameter of 0.1 to 5.0 μm.

[10] The support for a solid electrolyte according to any one of [1] to [9], wherein the nonwoven fabric includes a layer containing ultrafine fibers having a fiber diameter of 0.1 to 5.0 μm and a layer containing fibers having a fiber diameter of more than 5.0 μm and 30 μm or less.

[11] The support for a solid electrolyte according to

[10] , wherein the nonwoven fabric includes a layer (layer I) containing ultrafine fibers having a fiber diameter of 0.1 to 5.0 μm and a layer (layer II) containing fibers having a fiber diameter of more than 5.0 μm and 30 μm or less.

[12] The support for a solid electrolyte according to any one of [1] to

[11] , wherein the nonwoven fabric is thermally bonded over the entire surface.

[13] The support for the solid electrolyte according to any one of [1] to

[12] above, wherein the nonwoven fabric includes a layer (I layer) containing ultrafine fibers with a fiber diameter of 0.1 to 5.0 μm and a layer (II layer) containing fibers with a fiber diameter of more than 5.0 μm and 30 μm or less, the elastic recovery rate of the support is 45 to 99%, and the compression rate of the support is 0.1 to 9.7%.

[14] A solid electrolyte sheet including the support for the solid electrolyte according to any one of [1] to

[13] above and a solid electrolyte.

[15] The electrical conductivity of the solid electrolyte sheet is 1.0×10 -5 ~5.0×10 -1 s / m, the solid electrolyte sheet according to

[14] above.

Advantages of the Invention

[0013] The support for the solid electrolyte of the present invention is suitable for obtaining an electrolyte sheet with low electrical resistance. Further, the solid electrolyte sheet of the present invention has low electrical resistance.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described in detail. One embodiment of the present invention is a support for a solid electrolyte including a nonwoven fabric, characterized in that the elastic recovery rate of the support is 30 to 99%. The support for the solid electrolyte of this embodiment (hereinafter, also simply referred to as "support") includes a nonwoven fabric. There is no particular limitation on the type of nonwoven fabric, and for example, spunbond nonwoven fabric or meltblown nonwoven fabric can be used.

[0015] The elastic recovery rate of the support of this embodiment is 30 to 99%, preferably 45% or more, more preferably 50% or more, and preferably 98% or less, more preferably 97% or less. The elastic recovery rate greatly affects the followability of the electrolyte sheet to the electrode interface. That is, the higher the elastic recovery rate, the better the sheet follows the electrode interface, and the electrical resistance between the surface of the electrolyte sheet and the electrode is reduced.

[0016] The porosity of the support in this embodiment is preferably 30 to 95%, more preferably 35 to 90%, and still more preferably 40 to 85%. If the porosity is 30% or more, the retention amount of the solid electrolyte increases, so that the solid electrolytes come into sufficient contact with each other and the electrical resistance inside the sheet decreases. On the other hand, if the porosity is 95% or less, the strength as a support can be ensured, and the occurrence of short circuits in the electrode reaction of the active material can be suppressed.

[0017] The compressibility of the support in this embodiment is preferably 0.1% or more, more preferably 0.5% or more, still more preferably 1% or more, and preferably 40% or less, more preferably 35% or less, still more preferably 30% or less, and most preferably 9.7% or less. The production process of the electrolyte sheet includes press molding, and the higher the compressibility of the support, the more it contributes to the thinning of the sheet. Also, if the compressibility is high, a large amount of solid electrolyte can be filled inside the sheet, the contact area between the electrolytes increases, and the electrical resistance decreases. Furthermore, the higher the compressibility, the higher the flexibility of the electrolyte sheet, and during the electrode reaction, the interface on the electrolyte sheet side can follow the expansion and contraction of the electrode surface, reducing the contact resistance. Also, if the compressibility is 40% or less, the solid electrolyte can be sufficiently filled in the formation of the electrolyte sheet by press molding.

[0018] The nonwoven fabric contained in the support of this embodiment preferably contains synthetic fibers. Synthetic fibers are chemically stable and it is easy to obtain a high-quality electrolyte sheet. As materials for synthetic fibers, polyolefins such as polypropylene and polyethylene, polyesters such as polystyrene, polyphenylene sulfide, aramid, polyamideimide, polyimide, nylon, and polyethylene terephthalate (PET) can be used, and in particular, polyester is preferred. Since polyester has higher heat resistance than other resins, a support containing a nonwoven fabric containing this has excellent dimensional stability. Also, polyester does not react such as corrosion even when in contact with a solid electrolyte such as sulfide or lithium metal, and is chemically stable. Also, polyester has electrical insulation properties, which also contributes to suppressing short circuits of the electrode active material.

[0019] The support of this embodiment has a basis weight of 100 g / m 2 The thickness under load is preferably 5 to 200 μm, more preferably 7 μm to 180 μm, and even more preferably 10 to 150 μm. For a basis weight of 100 g / m 2 If the thickness under load is 5 μm or more, it is easy to increase the tensile strength, and the handleability during coating is good. On the other hand, for a basis weight of 100 g / m 2 If the thickness under load is 200 μm or less, the thickness after press molding can be suppressed, and the electrical resistance value of the electrolyte sheet can be lowered.

[0020] The nonwoven fabric contained in the support of this embodiment preferably contains fibers with a fiber length of 51 mm or more, more preferably 100 mm or more, and even more preferably 150 mm or more. If the fiber length is 51 mm or more, the support has excellent tensile properties, tear properties, and puncture properties. Also, if the fiber length is 51 mm or more, there are few shedding fibers, and it is easy to produce an electrolyte sheet with excellent shape retention.

[0021] The basis weight of the support of this embodiment is preferably 5 to 50 g / m 2 and more preferably 8 to 40 g / m 2 and even more preferably 10 to 30 g / m 2 . If the basis weight is 5 g / m 2 or more, it can be handled with good handleability in the coating process, and if it is 50 g / m 2 or less, it is sufficiently thin after press molding, so it is easy to lower the electrical resistance as an electrolyte sheet.

[0022] The apparent density of the support of this embodiment is preferably 0.069 to 0.97 g / cm 3 and more preferably 0.13 to 0.90 g / cm 3 and even more preferably 0.21 to 0.83 g / cm 3 . If the apparent density is 0.69 g / cm 3 or more, the strength as a support can be ensured, and the occurrence of short circuits in the electrode reaction of the active material can be suppressed. On the other hand, if the apparent density is 0.97 g / cm 3If the following conditions are met, the retention amount of the solid electrolyte increases, so that the solid electrolytes come into sufficient contact with each other, and the electrical resistance inside the sheet decreases.

[0023] The nonwoven fabric included in the support of the present embodiment preferably includes an ultrafine fiber layer having a fiber diameter of 0.1 to 5 μm. By including the ultrafine fiber layer, it is easy to form an electrolyte sheet in which the solid electrolyte is uniformly arranged, and the electrical resistance can be lowered. Further, by including the ultrafine fiber layer, bleeding during coating of the solid electrolyte is suppressed, and there are no pinholes or defects in the electrolyte sheet, so that it is easy to obtain a high-quality electrolyte sheet. Also, if the fiber diameter of the ultrafine fiber layer is 0.1 μm or more, the fiber strength is sufficiently high and the strength of the support is ensured, which is preferable. On the other hand, if the fiber diameter of the ultrafine fiber layer is 5 μm or less, the fiber spacing is made uniform, and it is easy to form an electrolyte sheet in which the solid electrolyte is uniformly arranged. From the above viewpoints, the fiber diameter of the ultrafine fiber layer is preferably 0.3 to 4.0 μm, more preferably 0.5 to 3.0 μm.

[0024] The nonwoven fabric included in the support of the present embodiment is preferably composed of at least two layers including an ultrafine fiber layer (I layer) having a fiber diameter of 0.1 to 5 μm and a fiber layer (II layer) having a fiber diameter of more than 5 μm and 30 μm or less. In this case, the I layer serves as a functional layer, and the II layer serves as a strength layer. By being a laminated nonwoven fabric of at least two layers combining the I layer and the II layer, a denser and network-like nonwoven fabric structure can be formed compared to the case where each layer is used alone as a support. As a result, when used as an electrolyte sheet, the electrolyte is more uniformly filled, and the electrical resistance decreases. As the laminated structure, a two-layer structure of I layer-II layer, a three-layer structure of I layer-II layer-I layer, a three-layer structure of II layer-I layer-II layer (that is, a three-layer structure in which the I layer is arranged as an intermediate layer between two II layers), and a four-layer structure of I layer-II layer-II layer-I layer are preferable.

[0025] The manufacturing method of the nonwoven fabric included in the support of the present embodiment is not limited. However, when providing the above II layer, the manufacturing method is preferably the spunbond method, the dry method, the wet method, or the like. Further, when providing the above I layer, the manufacturing method can preferably use a dry method or a wet method using ultrafine fibers, an electrospinning method, a melt-blown method, or force spinning. From the viewpoint of easily and densely forming the ultrafine fiber layer, the I layer is preferably formed by the melt-blown method. Further, the fibers forming the I layer may be used for manufacturing the nonwoven fabric after being slit or fibrillated by beating, partial dissolution, or the like.

[0026] Examples of the method for integrating the unbonded web and the method for forming the laminated nonwoven fabric having the I layer and the II layer include, for example, a method by integration by thermal bonding, a method by three-dimensional entanglement by injecting a high-speed water flow, and a method by integration with a particulate or fibrous adhesive. Integration by thermal bonding is preferable in that a laminated nonwoven fabric can be formed without using a binder. Examples of the method of integration by thermal bonding include integration by thermal embossing (thermal embossing roll method) and integration by high-temperature hot air (air-through method).

[0027] Integration by thermal bonding can be performed, for example, by thermal adhesion using a press roll (flat roll or embossing roll) at a temperature 50 to 120°C lower than the melting point of the synthetic resin and a linear pressure of 100 to 1000 N / cm. From the viewpoint of reducing the thickness and lowering the electrical resistance value of the electrolyte sheet, it is preferable to use a flat roll for thermal adhesion to obtain a nonwoven fabric that is thermally adhered over the entire surface. In this specification, the term "thermally adhered over the entire surface" refers to thermal adhesion over the entire surface of the nonwoven fabric, rather than so-called partial thermal adhesion (point bonding) where only a part of the nonwoven fabric is thermally adhered. Further, when the linear pressure in the thermal adhesion step is 100 N / cm or more, sufficient adhesion can be obtained and sufficient strength is easily exhibited. Further, when the linear pressure is 1000 N / cm or less, the deformation of the fibers is small, the apparent density is low, the porosity is high, and the desired effect is easily obtained.

[0028] In addition, the integration by thermal bonding can control the compression characteristics of the subsequent nonwoven fabric by controlling the fabric temperature before pressing when entering the press roll in the thermal bonding process. The fabric temperature before pressing is the temperature of the nonwoven fabric (web) 50 cm upstream from the roll nip point. For example, in the case of a polyester material, specifically, by setting the fabric temperature before pressing in the range of 40 to 120 °C, it is possible to obtain an elastic recovery rate and a compression rate within the above-mentioned range. By setting the fabric temperature before pressing high, the crystallinity of the yarn is promoted in advance, and thereby, while ensuring the minimum amount of amorphous required for adhesion between fibers, over-bonding can be suppressed, and a support with a high elastic recovery rate can be obtained. There is no particular limitation on the method of adjusting the fabric temperature before pressing in the range of 40 to 120 °C, but examples include a method of effectively utilizing the heat dissipation of the heating press roll with a heat-insulating plate, and a method of preheating the nonwoven fabric with a preheating roll.

[0029] Another embodiment of the present invention is a solid electrolyte sheet including the support for the solid electrolyte and a solid electrolyte. Hereinafter, a solid electrolyte sheet including the support and the solid electrolyte of the present embodiment will be described. The electric conductivity of the solid electrolyte sheet including the support and the solid electrolyte of the present embodiment is preferably 1.0×10 -5 ~5.0×10 -1 S / m, more preferably 5.0×10 -5 ~1.0×10 -1 S / m, and even more preferably 1.0×10 -4 ~5.0×10 -2 S / m.

[0030] The solid electrolyte used in combination with the support of the present embodiment is not particularly limited as long as it has lithium ion conductivity, and examples include inorganic solid electrolytes such as sulfide solid electrolytes and oxide solid electrolytes, and polymer solid electrolytes. Examples of the sulfide-based solid electrolyte include, for example, Li2S-P2S5, Li2S-Si, Li2S-P2S5-GeS2, and Li2S-B2S3-based glasses, as well as Li 10 GeP2S 12(LGPS system) or Li6PS5Cl (Argyrodite system) can be used. Among these, in particular, Argyrodite-based materials with high lithium ion conductivity and high chemical stability are preferably used. Examples of oxide-based solid electrolytes include Li7La3Zr20 12 , LiTi2Z(PO4)3, LiGe02(P04)3, LiLaTiO3, and the like.

[0031] When the solid electrolyte is coated on the support of this embodiment, the solid electrolyte can be coated in a slurry state. The slurry used for coating can be prepared by putting solid electrolyte particles and a binder into a solvent and mixing them. It is preferable to select a solvent for the slurry that is less likely to deteriorate the solid electrolyte. For example, it is preferable to use an aprotic nonpolar solvent typified by hydrocarbon solvents such as hexane, heptane, octane, nonane, decane, decalin, toluene, and xylene. In particular, it is more preferable to use an ultra-dehydrated solvent with a water content of 0.001% by mass (10 ppm) or less. After filling the slurry into the pores of the support, the solvent of the slurry is removed by drying. After the slurry coating and drying of the solvent, the composite of the support and the solid electrolyte is press-molded. Examples of the conditions for press molding include a pressure of 5 to 50 MPa, a temperature of 50 to 200 °C, and a press time of 1 to 30 minutes.

Examples

[0032] Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to these examples in any way. Hereinafter, unless otherwise specified, the length direction of the nonwoven fabric is the MD direction (machine direction), and the width direction is the direction perpendicular to the length direction in the plane of the nonwoven fabric.

[0033] (1) Basis weight (g / m 2 ) In accordance with the method specified in JIS L-1906, test pieces measuring 20 cm in length and 25 cm in width were taken at 3 locations per 1 m in the width direction of the sample and 3 locations per 1 m in the length direction, for a total of 9 locations per 1 m × 1 m. The mass was measured, and the average value was converted to the mass per unit area to obtain the basis weight.

[0034] (2) Thickness (μm) In accordance with the method specified in JIS L-1906, the thicknesses at 10 locations per 1 m in the width of the test piece were measured under the condition of a load of 9.8 kPa, and the average value was obtained.

[0035] (3) Apparent density (g / cm 3 ) Using the basis weight (g / m 2 ) measured in (1) above and the thickness (μm) measured in (2) above, after adjusting the units, the following formula: Apparent density = (basis weight) / (thickness) was used to calculate the apparent density.

[0036] (4) Porosity (%) Using the apparent density (g / cm 3 ) calculated in (3) above, the following formula: Porosity = {1 - (apparent density) / (resin density)} / 100 was used to calculate the porosity.

[0037] (5) Fiber diameter (μm) The nonwoven fabric was cut into 10 cm × 10 cm pieces, pressed between iron plates at 60 °C top and bottom under a pressure of 0.30 MPa for 90 seconds, and then platinum was vapor-deposited. Using an SEM apparatus (JSM-6510, manufactured by JEOL Ltd.), the nonwoven fabric with platinum vapor-deposited was photographed under the conditions of an acceleration voltage of 15 kV and a working distance of 21 mm. The magnification for photography was set as follows: for yarns with an average fiber diameter of less than 0.5 μm, 10,000 times; for yarns with an average fiber diameter of 0.5 μm or more and less than 1.5 μm, 6,000 times; and for yarns with an average fiber diameter of 1.5 μm or more, 4,000 times. The photographic field of view at each magnification was 12.7 μm × 9.3 μm at 10,000 times, 21.1 μm × 15.9 μm at 6,000 times, and 31.7 μm × 23.9 μm at 4,000 times. More than 100 fibers were randomly photographed, and the length of all fiber diameters was measured. However, fibers fused together in the yarn length direction were excluded from the measurement targets. The following formula: Dw = ΣWi·Di = Σ(Ni·Di 2 ) / (Ni·Di) {In the formula, Wi = weight fraction of fiber diameter Di = Ni·Di / ΣNi·Di, and Ni is the number of fibers with fiber diameter Di.} The weight-average fiber diameter (Dw) obtained by the formula was taken as the average fiber diameter (μm).

[0038] (6) Tensile strength (N / 15 mm) Excluding 10 cm from each end of the sample (nonwoven fabric, support), test pieces with a width of 15 mm × a length of 20 cm were cut out at 5 locations per 1 m width. A load was applied until the test piece broke, and the average value of the strength at the maximum load of the test piece in the MD direction was determined.

[0039] (7) Elastic recovery rate, compression rate Using an MCT-50 micro compression tester manufactured by Shimadzu Corporation, the elastic recovery rate and compression rate were measured. The test conditions were measured in a load-unloading mode in which a load was applied to the sample up to the maximum test force and then unloaded up to the minimum test force. The minimum test force was 0.05 mN, and the maximum test force was set as the test force at 10% deformation in the compression mode. The elastic recovery rate and compression rate were calculated as follows. Elastic recovery rate (Rr) = {L2 / (L1 - L2)} × 100 Compression rate (Cr) = (L1 / d) × 100 d: Thickness of non-woven fabric (support) L1: Displacement difference between the maximum test force and the minimum test force in the loading mode L2: Displacement difference between the maximum test force and the minimum test force in the unloading mode

[0040] (8) Measurement of electrical resistance (electrical conductivity (S / m)) As the measuring device, a Digital Super Megohmmeter manufactured by HIOKI and an electrode SME-8311 for flat samples manufactured by HIOKI were used. A test piece (solid electrolyte sheet) of 100 mm × 100 mm was prepared, and the electrical conductivity was measured under the measurement conditions of a voltage of 10 V and a measurement time of 60 seconds. In addition, the solid electrolyte sheet used for the measurement was prepared as follows. To the amorphous powder of Li2S-P2S5 (80:20 mol%), which is a sulfide electrolyte, a xylene solution of SBR (electrolyte binder) was added so that SBR was 1% of the mass of the amorphous powder to prepare a mixed solution. Further, a xylene solution of NBR (electrolyte layer binder) was added to this mixed solution so that NBR was 0.5% of the amorphous powder, and an appropriate amount of dehydrated xylene was added for viscosity adjustment. This mixed solution was put into a kneading container, and zirconia balls were put in so as to occupy 1 / 3 of the kneading container, and the electrolyte slurry was prepared by stirring at 3000 rpm for 5 minutes. The support was impregnated with the above electrolyte slurry, further nipped by a roll press, and smoothed with a blade to obtain a composite in which the slurry sufficiently penetrated into the support. This composite was dried with a hot air dryer to prepare an electrolyte sheet.

[0041] [Examples 1 to 7, 12] As the fiber layer (layer II) with a fiber diameter exceeding 5 μm and not exceeding 30 μm, polyethylene terephthalate (PET) resin was extruded from a spunbond spinneret (V-shaped nozzle) at a spinning temperature of 290°C. The filaments were symmetrically cooled from both sides by a cooling device immediately below the spinneret (both with a wind speed of 0.5 m / s), and drawn by a draw jet to obtain continuous long fibers (fiber diameter 15 μm). The fibers were opened and dispersed and deposited on a web conveyor to form a web. Next, as the ultra-fine fiber layer (layer I), PET resin was used and spun by the meltblown method under the condition of a spinning temperature of 290°C and blown onto the above web. At this time, the distance from the meltblown nozzle to the above web was set to 300 mm, the suction force at the collection surface immediately below the meltblown nozzle was set to 0.2 kPa, and the wind speed was set to 7 m / sec. Further, continuous long fibers (fiber diameter 15 μm) produced by the same spunbond method as above were laminated thereon to obtain a laminated web. Furthermore, the laminated web was integrated by a press roll (calendar roll), and a non-woven fabric was produced to have a predetermined thickness by adjusting the calendar line pressure and temperature as shown in Table 1 below, and this was used as a support. Incidentally, the cloth temperature before the calendar, which is important for controlling the compression characteristics, was adjusted to 50, 70, or 90°C by adjusting the position of the heat-insulating plate of the heating roll.

[0042] [Example 8] As shown in Table 1 below, a non-woven fabric was produced in the same manner as in Example 1 except that polyphenylene sulfide (PPS) resin was used as a raw material and the spinning temperature, calendar temperature, cloth temperature, thickness, and apparent density were adjusted to predetermined values, and this was used as a support.

[0043] [Example 9] As shown in Table 1 below, PET resin short fibers with a fiber diameter of 4 μm and a fiber length of 5 mm were collected on a net to 20 g / m 2 by the papermaking method, dehydrated and dried, and then crimped by a flat roll so that the fibers did not dissipate to obtain a short fiber non-woven fabric. During crimping, the calendar temperature and cloth temperature were appropriately adjusted and calendared to obtain the desired thickness, porosity, and compression characteristics.

[0044] [Example 10] As the fiber layer (layer II) with a fiber diameter exceeding 5 μm and not exceeding 30 μm, PET resin was discharged from a spunbond spinneret (V-type nozzle) at a spinning temperature of 290°C. The yarn was symmetrically cooled from both sides by a cooling device immediately below the spinneret (both with a wind speed of 0.5 m / s), and then drawn by a draw jet to obtain continuous long fibers (fiber diameter: 15 μm). The fibers were opened and dispersed and deposited on a web conveyor to form a web. Next, as shown in Table 1 below, the web was integrated by calendar rolls, and a nonwoven fabric was produced to have a predetermined thickness by adjusting the calendar linear pressure, and this was used as a support. Note that the fabric temperature before calendaring was adjusted to 70°C.

[0045] [Example 11] As the ultrafine fiber nonwoven fabric layer (layer I), PET resin was used and spun by the meltblown method under the condition of a spinning temperature of 290°C and deposited on a web conveyor. At this time, the distance from the meltblown nozzle to the web was set to 300 mm, the suction force on the collection surface immediately below the meltblown nozzle was set to 0.2 kPa, and the wind speed was set to 7 m / sec. Next, as shown in Table 1 below, the web was integrated by calendar rolls, and a nonwoven fabric was produced to have a predetermined thickness by adjusting the calendar linear pressure, and this was used as a support. Note that the fabric temperature before calendaring was adjusted to 70°C.

[0046] [Example 13] Similar to Example 1, as the fiber layer (Layer II) with a fiber diameter exceeding 5 μm and not exceeding 30 μm, polyethylene terephthalate (PET) resin was discharged from a spunbond spinneret (V-shaped nozzle) at a spinning temperature of 290°C. The yarn was symmetrically cooled from both sides by a cooling device immediately below the spinneret (both with a wind speed of 0.5 m / s), and then drawn by a draw jet to obtain continuous long fibers (fiber diameter: 15 μm). The fibers were opened and dispersed and deposited on a web conveyor to form a web. Next, as the ultra-fine fiber layer (Layer I), PET resin was used and spun by the meltblown method under the condition of a spinning temperature of 290°C, and then blown onto the above web. At this time, the distance from the meltblown nozzle to the above web was set to 300 mm, the suction force at the collection surface immediately below the meltblown nozzle was set to 0.2 kPa, and the wind speed was set to 7 m / sec. Furthermore, the laminated web was integrated with a press roll (calendar roll), and a non-woven fabric was produced to have a predetermined thickness by adjusting the calendar line pressure and temperature as shown in Table 1 below, and this was used as a support. Note that the temperature of the fabric before calendaring, which is important for controlling the compression characteristics, was adjusted to 70°C by adjusting the position of the heat insulation plate of the heating roll.

[0047] [Comparative Example 1] For a short fiber non-woven fabric made of PET resin with a fiber diameter of 4 μm and a fiber length of 5 mm, calendaring was performed as shown in Table 1 below to obtain a desired thickness, porosity, and compression characteristics. Note that no special consideration was given to the fabric temperature, and calendaring was carried out at the ambient temperature of 23°C.

[0048] [Comparative Example 2] A non-woven fabric was produced in the same manner as in Example 10 except that the temperature of the fabric before calendaring was set to the ambient temperature of 23°C as shown in Table 1 below, and this was used as a support.

[0049] [Table 1] [Industrial Applicability]

[0050] The support for the solid electrolyte of the present invention can be combined with inorganic solid electrolytes such as sulfide solid electrolytes and oxide solid electrolytes, and polymer solid electrolytes, etc., to obtain a solid electrolyte sheet with low electrical resistance, and thus can be suitably used as a member for all-solid-state batteries.

Claims

1. A support for a solid electrolyte containing a non-woven fabric, characterized in that the elastic recovery rate of the support is 30 to 99%, the support for a solid electrolyte.

2. The support for a solid electrolyte according to claim 1, wherein the porosity of the support is 30 to 95%.

3. The support for a solid electrolyte according to claim 1 or 2, wherein the compression rate of the support is 0.1 to 40%.

4. The support for a solid electrolyte according to claim 1 or 2, wherein the non-woven fabric contains synthetic fibers.

5. The support for a solid electrolyte according to claim 4, wherein the synthetic fiber is polyester.

6. The thickness of the support under a load of 100 g / m 2 is 5 to 200 μm, and the support for a solid electrolyte according to claim 1 or 2.

7. The support for a solid electrolyte according to claim 1 or 2, wherein the non-woven fabric contains fibers having a fiber length of 51 mm or more.

8. The basis weight of the support is 5 to 50 g / m 2 The support for a solid electrolyte according to claim 1 or 2, wherein the basis weight is as defined above.

9. The support for a solid electrolyte according to claim 1 or 2, wherein the non-woven fabric contains ultrafine fibers having a fiber diameter of 0.1 to 5.0 μm.

10. The support for a solid electrolyte according to claim 1 or 2, wherein the non-woven fabric includes a layer containing ultrafine fibers having a fiber diameter of 0.1 to 5.0 μm and a layer containing fibers having a fiber diameter of more than 5.0 μm and 30 μm or less.

11. The support for a solid electrolyte according to claim 10, wherein the non-woven fabric includes a layer (layer I) containing ultrafine fibers having a fiber diameter of 0.1 to 5.0 μm and a layer (layer II) containing fibers having a fiber diameter of more than 5.0 μm and 30 μm or less.

12. The support for a solid electrolyte according to claim 1 or 2, wherein the non-woven fabric is thermally bonded over the entire surface.

13. The support for a solid electrolyte according to claim 1 or 2, wherein the non-woven fabric includes a layer (layer I) containing ultrafine fibers having a fiber diameter of 0.1 to 5.0 μm and a layer (layer II) containing fibers having a fiber diameter of more than 5.0 μm and 30 μm or less, the elastic recovery rate of the support is 45 to 99%, and the compression rate of the support is 0.1 to 9.7%.

14. A solid electrolyte sheet comprising the support for a solid electrolyte according to claim 1 or 2 and a solid electrolyte.

15. The electric conductivity of the solid electrolyte sheet is 1.0 × 10 -5 to 5.0 × 10 -1 S / m, and the solid electrolyte sheet according to claim 14.

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