Title of the invention: composite electrolyte membrane and all-solid-state battery comprising the composite electrolyte membrane Technical field [One] This application claims priority based on Korean Patent Application No. 10-2018-0121266 filed on October 11, 2018. The present invention relates to a composite solid electrolyte membrane including an electrolyte layer and a phase change layer, and an all-solid-state battery including the same. [2] Background [3] Recently, interest in energy storage technology is increasing. As the field of application to mobile phones, camcorders, notebook PCs, and even electric vehicles is expanded, efforts for research and development of electrochemical devices are increasingly being materialized. Electrochemical devices are the field that is receiving the most attention in this respect, and the development of secondary batteries capable of charging and discharging among them is the focus of interest, and in recent years, in developing such batteries, new electrodes have been developed to improve capacity density and specific energy. It is proceeding with research and development on the design of and battery. [4] Among the currently applied secondary batteries, the lithium secondary battery developed in the early 1990s has the advantage of having a higher operating voltage and significantly higher energy density than conventional batteries such as Ni-MH, Ni-Cd, and sulfuric acid-lead batteries using aqueous electrolyte solutions. Is in the limelight. [5] In such a lithium secondary battery, a liquid electrolyte (electrolyte) such as a flammable organic solvent has been conventionally used. However, in the case of a battery using a liquid electrolyte, there is a possibility that problems such as leakage, ignition, and explosion of the electrolyte may occur. In order to solve this problem and secure intrinsic safety, studies using a solid electrolyte instead of a liquid electrolyte are being actively conducted. It is called an All Solid State Secondary Battery, in which all of the other components including the electrolyte are made of solid. All-solid-state batteries are attracting attention as a next-generation lithium secondary battery in terms of safety, high energy density, high power, and simplification of manufacturing processes. [6] However, in such an all-solid-state battery, since both the electrode and the solid electrolyte membrane are solid and there is no liquid electrolyte, there is a problem that a dead space, that is, a void without ion conductivity, occurs at the interface between the electrode and the solid electrolyte membrane. [7] In particular, when the electrode surface is uneven due to the shape of the electrode active material, aggregation of the conductive material, or the lifting of the binder polymer, more dead space occurs, resulting in increased resistance between the electrode and the solid electrolyte membrane, and the life of the battery. There is a problem that adversely affects performance. [8] In order to solve this problem, there have been attempts to add a liquid electrolyte to an all-solid battery. However, since the injection of the liquid electrolyte proceeds after assembly of the electrode assembly, it must be injected in an excessive amount, and there is a problem that the injected liquid electrolyte softens the solid electrolyte membrane. [9] In addition, when lithium metal is used as a negative electrode active material, there is a problem that as charging and discharging is repeated, dendrites are formed on the surface of the negative electrode, so that the electrode thickness becomes thick and the cycle characteristics decrease. [10] Detailed description of the invention Technical challenge [11] An object of the present invention is to provide a composite electrolyte membrane including a phase change layer in order to solve the above problems. In addition, it is another object of the present invention to provide an all-solid-state battery including the composite electrolyte membrane. Other objects and advantages of the present invention will be understood by the following description. On the other hand, it will be readily appreciated that the objects and advantages of the present invention can be realized by means or methods described in the claims, and combinations thereof. [12] Means of solving the task [13] The present invention relates to a composite electrolyte membrane for an all-solid-state battery as to solve the above-described problem. The first aspect of the present invention relates to the composite electrolyte membrane, wherein the composite electrolyte membrane includes an electrolyte layer and a phase change layer sequentially stacked, and the phase change layer includes a plurality of pores, and a porous sheet including a polymer resin And a filling material filling the pores of the porous sheet, wherein the filling material is present in a solid state at 26°C or lower and in a liquid state at a temperature of 35°C or higher. [14] In the second aspect of the present invention, in the first aspect, the filling material is ethylene carbonate (EC), polyethylene glycol (PEG) having a weight average molecular weight of 1,000 or more, and succinonitrile (SN). ) And a cyclic phosphate (cyclic phosphate, CP), or a mixture of two or more of them. [15] In a third aspect of the present invention, in the first or second aspect, the electrolyte layer includes a sulfide-based solid electrolyte, an oxide-based solid electrolyte, and a polymer-based solid electrolyte, and the polymer-based solid electrolyte is a polymer resin and lithium It contains salt. [16] A fourth aspect of the present invention is, in any one of the first to third aspects, wherein the electrolyte layer comprises a polymer resin layer including a polymer resin and a surface facing the phase change layer of both sides of the polymer resin layer. A lithium salt layer coated with a lithium salt is formed on all or at least part of it. [17] A fifth aspect of the present invention is, in any one of the first to fourth aspects, wherein the electrolyte layer includes a polymer resin and a lithium salt, and the polymer resin is a polyether-based polymer, a polycarbonate-based polymer, and an acrylate. At least one selected from among polymers, polysiloxane polymers, phosphazene polymers, polyethylene derivatives, alkylene oxide derivatives, phosphate ester polymers, poly agitation lysine, polyester sulfide, polyvinyl alcohol and polyvinylidene fluoride It includes, wherein the lithium salt and the polymer resin are mixed in a ratio of 1:5 to 1:30 in a molar ratio. [18] In a sixth aspect of the present invention, in any one of the first to fifth aspects, the porous sheet is a film or nonwoven fabric containing a polyolefin-based polymer resin and having a porosity of 30 vol% to 80 vol%. [19] The seventh aspect of the present invention relates to an all-solid-state battery, wherein the all-solid-state battery includes a negative electrode, a positive electrode, and a composite electrolyte membrane interposed between the negative electrode and the positive electrode, and the electrolyte layer of the composite electrolyte membrane faces the negative electrode, and The conversion layer is disposed to face the anode, and the composite electrolyte membrane is according to any one of the first to sixth aspects described above. [20] In the eighth aspect of the present invention, in the seventh aspect, the filling material of the phase change layer is liquefied by reacting with the lithium salt and then the liquefied state is maintained, and the liquefied filling material is between the phase change layer and the electrolyte layer and It is maintained to fill the interface between the phase change layer and the anode. [21] In addition, the present invention provides a method for manufacturing an all-solid-state battery. The ninth aspect of the present invention relates to a method for manufacturing the battery, wherein the method includes (S1) preparing a negative electrode, (S2) forming a solid electrolyte layer on the surface of the negative electrode, (S3) preparing a porous sheet, and Impregnating this with a liquid filling material, (S4) cooling the resultant of (S3) to solidify the filling material to form a phase change layer, (S5) laminating the phase change layer on the electrolyte layer, And (S6) preparing an anode and laminating it on the phase change layer. [22] In the tenth aspect of the present invention, in the ninth aspect, (S7) forming a lithium salt layer by applying a lithium salt on the electrolyte layer before performing the step (S5) is further performed. [23] In an eleventh aspect of the present invention, in the ninth or tenth aspect, the step (S8) of liquefying the filling materials by heating the manufactured battery after performing the step (S6) and leaving it for a predetermined period of time is further performed. [24] Effects of the Invention [25] In the composite electrolyte membrane according to the present invention, a phase change layer is disposed on a surface facing an electrode, for example, an anode. The phase change layer fills a dead space that is physically disconnected between the positive electrode and the composite electrolyte membrane by liquefying the filling material by heating such as an increase in the internal temperature of the battery. Interfacial resistance can be lowered. [26] In addition, the filling material of the phase change layer is liquefied to reduce the dead space between the composite electrolyte membrane and the electrode interface, thereby reducing non-uniformity in contact between the composite electrolyte membrane and the electrode surface. Accordingly, it is possible to increase the adhesion between the electrode and the porous polymer sheet layer, and to lower the interface resistance between the porous polymer sheet layer and the electrolyte layer. [27] The phase change layer may fill a dead space in the electrode by liquefying the filled filling material. Accordingly, the ionic conductivity of lithium ions can be increased and resistance can be reduced, and the lifespan performance of the battery can be improved. [28] The phase change layer is filled and liquefied to react with the negative electrode active material layer in the negative electrode to form an SEI film on the surface of the negative electrode, thereby enhancing the life performance of the battery. [29] Since the phase change layer functions as a liquid electrolyte by liquefying the filling material filling it, it is possible to improve the output of the battery by increasing the ionic conductivity of the battery. [30] Since the all-solid-state battery according to the present invention includes a porous sheet layer, it is possible to prevent softening of the polymer electrolyte generated when the liquefied liquid electrolyte contacts the electrolyte layer and the resulting deterioration in mechanical properties. In addition, it is possible to reduce the growth of lithium dendrites by including the porous sheet layer. [31] The present invention can provide an all-solid-state battery with improved safety. [32] Brief description of the drawing [33] The drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to better understand the technical idea of ​​the present invention together with the content of the present invention, so the present invention is limited to the matters described in such drawings. Is not interpreted. Meanwhile, the shape, size, scale, or ratio of elements in the drawings included in the present specification may be exaggerated to emphasize a clearer description. [34] 1A is a schematic diagram showing a cross-section of an all-solid-state battery according to an embodiment of the present invention. [35] 1B is a cross-sectional view of an all-solid-state battery according to an embodiment of the present invention, schematically showing a state in which the filling material of the phase change layer is liquefied. [36] 2A is a schematic diagram showing a cross section of an all-solid-state battery according to an embodiment of the present invention. [37] 2B is a cross-sectional view of an all-solid-state battery according to an embodiment of the present invention, schematically showing a state in which the filling material of the phase change layer is liquefied. [38] 3 shows the results of an experiment for evaluating the capacity retention rate of a battery according to Examples and Comparative Examples of the present invention. [39] Mode for carrying out the invention [40] Hereinafter, the present invention will be described in detail. The terms or words used in the specification and claims are not to be construed as limited to their usual or dictionary meanings, and the inventor may appropriately define the concept of terms in order to describe his own invention in the best way It should be interpreted as a meaning and concept consistent with the technical idea of ​​the present invention based on the principle that there is. Accordingly, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention, and do not represent all the technical spirit of the present invention. It should be understood that there may be equivalents and variations. [41] [42] In the entire specification of the present application, when a certain part is said to be ``connected'' with another part, this includes not only ``directly connected'' but also ``electrically connected'' with another element interposed therebetween. . [43] [44] The terms "about", "substantially" and the like used throughout this specification are used as a meaning at or close to the numerical value when manufacturing and material tolerances specific to the stated meaning are presented, and are accurate to aid the understanding of the present application. Or absolute figures are used to prevent unfair use of the stated disclosure by unconscionable infringers. [45] [46] In the entire specification of the present application, the term "combination(s) thereof" included on the surface of the Makushi-type refers to one or more mixtures or combinations selected from the group consisting of the constituent elements described in the expression of the Makushi-type, It means to include at least one selected from the group consisting of the above constituent elements. [47] [48] In the entire specification of the present application, the description of "A and/or B" means "A or B or both". [49] [50] In addition, when used in the present specification, "comprise, include" and/or "comprising, including" refers to the mentioned shapes, numbers, steps, actions, members, elements, and/or groups thereof. It specifies existence and does not exclude the presence or addition of one or more other shapes, numbers, actions, members, elements and/or groups. [51] [52] In an all-solid-state battery using a solid-type electrolyte other than a liquid electrolyte, an electrolyte membrane including a solid electrolyte is disposed between a positive electrode and a negative electrode. It serves as a safety device to prevent. In addition, since the electrolyte membrane allows lithium ions to move to the ion conductive layer, charging and discharging of the battery is possible. [53] However, since the electrolyte membrane is solid, a separation may occur between the battery element facing the electrolyte membrane, for example, the solid electrolyte membrane and the electrode, and this becomes a void without ion conductivity, that is, a death space. In this case, the current is concentrated in a portion other than a dead space, and accordingly, generation of lithium dendrites may be accelerated. In addition, an internal short circuit may occur due to the growth of dendrites. [54] In order to solve this problem, the present invention has devised a composite electrolyte membrane in which a phase change layer is disposed on the surface of the electrolyte membrane. [55] [56] Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. [57] In one embodiment of the present invention, the composite electrolyte membrane has a structure in which an electrolyte layer and a phase change layer are sequentially stacked. The composite electrolyte membrane is used as an electrolyte membrane for an all-solid battery, and the electrolyte layer includes a solid electrolyte material. Here, the phase change layer includes a porous sheet and a filler material that fills the pores of the porous sheet, and the filler material exists in a solid state at room temperature or below, and in a liquid state with fluidity at a temperature of 30° C. or higher. It means a substance whose phase changes In the present specification, room temperature means 23° C. to 26° C. and may be 24° C. or higher within the above range. The composite electrolyte membrane may be disposed between an anode and a cathode to be applied as an electrolyte membrane for an all-solid battery. The phase change layer may be disposed to face the electrode, for example, may be disposed to face the anode. 1A is a schematic diagram showing a cross section of a composite electrolyte membrane and a battery 100 including the same according to an embodiment of the present invention. Referring to this, a phase change layer 130 and an electrolyte layer 40 are interposed between the anode 110 and the cathode 120, and the phase change layer is disposed to face the anode. [58] The electrolyte layer contains a solid electrolyte material. The solid electrolyte material may include one or more of a polymer-based solid electrolyte, an oxide-based solid electrolyte, and a sulfide-based solid electrolyte. Since the solid polymer electrolyte of the present invention serves to transfer lithium ions in the electrode, a material having high ionic conductivity, for example, 10 -6 s/cm or more, 10 -5 s/cm or more, or 10 -4 Anything that is more than s/cm can be used. [59] In the present invention, it is preferable that the solid electrolyte material includes a polymer-based solid electrolyte material. In one embodiment of the present invention, the polymer-based solid electrolyte is a polymer solid electrolyte formed by adding a polymer resin to a solvated lithium salt, or an organic electrolyte containing an organic solvent and a lithium salt, an ionic liquid, a monomer, or an oligomer. It may be a polymer gel electrolyte in which the etc. is contained in a polymer resin. In a specific embodiment of the present invention, the polymer-based solid electrolyte is a polymer resin, for example, a polyether-based polymer, a polycarbonate-based polymer, an acrylate-based polymer, a polysiloxane-based polymer, a phosphazene-based polymer, a polyethylene derivative, Alkylene oxide derivatives such as PEO (polyethyleye oxide), phosphoric acid ester polymer, poly agitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, polymers containing ionic dissociation groups, etc. have. In addition, the polymer solid electrolyte is a polymer resin, a branched copolymer in which an amorphous polymer such as PMMA, polycarbonate, polysiloxane (pdms), and/or phosphazene is copolymerized with a comonomer in a PEO (polyethylene oxide) main chain, a comb-shaped polymer resin. (comb-like polymer) and a crosslinked polymer resin may be included, and a mixture of the polymers may be included. [60] In addition, the polymer gel electrolyte includes an organic electrolyte solution containing a lithium salt and a polymer resin, and the organic electrolyte solution includes 60 to 400 parts by weight based on the weight of the polymer resin. The polymer applied to the gel electrolyte is not limited to a specific component, but for example, polyether-based, PVC-based, PMMA-based, polyacrylonitrile (PAN), polyvinylidene fluoride (PVdF), and polyvinyl fluoride It may include poly(vinylidene fluoride-hexafluoropropylene: PVdF-HFP, etc.), and may be a mixture of the above polymers. [61] In one embodiment of the present invention, the lithium salt may be represented by Li + X - . In a specific exemplary embodiment of the present invention, the lithium salt is Li cation + to contain the anion is F - , Cl - , Br - , I - , NO 3 - , N (CN) 2 - , BF 4 - , ClO 4 - , AlO 4 - , AlCl 4 - , PF 6 - , SbF6 - , AsF 6 - , F 2C 2 O 4 - , BC 4 O 8 - , (CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3 ) 4 PF 2 - , (CF 3 ) 5 PF - , (CF 3 ) 6 P - , CF 3 SO 3 -, C 4 F 9 SO 3 - , CF 3 CF 2 SO 3 - , (CF 3 SO 2 ) 2 N - , (F 2 SO 2 ) 2 N - , CF 3 CF 2 (CF 3 ) 2 CO - , ( CF 3 SO 2 ) 2 CH - , CF 3 (CF 2 ) 7 SO 3 - , CF 3 CO 2 - , CH 3 CO 2 - , SCN - , and (CF 3 CF 2 SO 2 ) 2 N - comprise at least one selected from the group consisting of I can. [62] In one embodiment of the present invention, when the electrolyte layer includes a polymer resin and a lithium salt, the lithium salt and the polymer resin may be included in a ratio of 1: 5 to 1:30 based on a molar ratio. For example, when the polymer resin is polyethylene oxide, [EO]:[Li + ] may have a molar ratio of 5:1 to 30:1. [63] The phase change layer includes a porous sheet and a filling material filling the pores of the porous sheet. [64] The porous sheet includes a polymer material and is a porous film or nonwoven material including a plurality of pores. In particular, as long as it can be used as a separator material for an electrochemical device, it can be used without special restrictions. The pores are interconnected with each other, so that gas or liquid can pass from one side of the substrate to the other side. [65] In one embodiment of the present invention, the porous sheet may have a thickness of 5 μm to 50 μm. When the thickness of the porous sheet satisfies the above numerical range, the liquefied filler material may be sufficiently impregnated, and the distance through which lithium ions travel is short, so that the ionic conductivity of the composite electrolyte membrane may be maintained at a desired level. [66] The porosity of the porous sheet may have a range of 30 vol% to 80 vol%. Within the above range, the porosity may have a value of 60 vol% or less, 50 vol% or less, or 40 vol% or less, or 30 vol% or less. In addition, within the above range, the porosity may have a value of 20 vol% or more, 30 vol% or more, 40 vol% or more, or 60 vol% or more. For example, the porosity may have a value of 30 vol% to 60 vol%. The filler material used in the present invention may function as a plasticizer to soften the polymer material. Therefore, if the porosity is too high, a large amount of liquefied filling material may flow into the electrolyte layer through the pores of the porous sheet. If the electrolyte layer contains a polymer-based solid electrolyte, the solid electrolyte is softened by the filling material. Physical properties may be degraded. However, if the porosity is too low, the movement of lithium ions may be reduced. Accordingly, when the porosity range is satisfied, the liquefied filler material can prevent softening of the electrolyte layer by passing through the pores of the porous sheet, and at the same time, the ionic conductivity of the battery can be maintained at a desirable level. In the present invention, the porosity in the present invention can be measured by the following method. In one embodiment of the present invention, the method for measuring the porosity was to measure the diameter of the pores filled with mercury at a constant pressure according to ASTM D 4284-92, and the range of the applied pressure was between 0.5 and 60,000 psi. While continuously applying pressure at, the pores at each constant pressure are measured, and at this time, the volume of mercury filled in the separator is measured to measure the porosity. The porosity measurement is automatically measured and the calculated value is output. The available equipment is Autopore IV 9500 from Micrometrics, and the size range of pores that can be measured is 0.003㎛ to 360㎛. [67] In a specific embodiment of the present invention, the porous sheet is polyethylene; Polypropylene; Polybutylene; Polypentene; Polyhexene; Polyoxene; Or a copolymer of two or more of ethylene, propylene, butene, pentene, 4-methylpentene, hexene, and octene; Any one or a mixture of two or more of them may be included. However, it is not limited thereto. [68] In addition, the porous sheet may reduce the growth of lithium dendrites, and may increase the mechanical strength of the composite electrolyte membrane. This seems to be because the porous polymer sheet layer itself serves as a support layer and at the same time, the porous polymer sheet layer is impregnated with a liquefied plasticizer and a lithium salt to fill the pores in the porous polymer sheet layer. [69] [70] The filling material may be used as an organic solvent for a liquid electrolyte in the present technical field, and is in a solid state at room temperature and melted and liquefied under conditions of, for example, about 30° C. or higher as the temperature rises. [71] In a specific embodiment of the present invention, the filling material maintains a solid state at a temperature below room temperature, but when the internal temperature rises during the aging step of the battery or driving the battery, it melts and changes to a liquid state when it reaches a certain temperature condition. . For example, when aging is performed at about 60° C. for about 10 seconds after assembling the battery, the filling material may be liquefied. In this case, the liquefied filler material may act as a solvent for the lithium salt. That is, the lithium salt in contact with the liquefied filling material is dissolved therein to become a liquid electrolyte. On the other hand, the filling material has a property of solidifying again when the temperature is lowered. However, when the filling material is mixed with a lithium salt after being liquefied, it is not solidified and remains in a liquid state even if the temperature falls below the melting point. This is because the melting point is lowered as the filling material is mixed with the lithium salt. [72] In a specific embodiment of the present invention, when the filling material is once changed to a liquid state, the temperature of the battery does not necessarily need to be higher than the melting point of the filling material when the battery is driven. [73] In a specific embodiment of the present invention, the filling material is ethylene carbonate, polyethylene glycol having a weight average molecular weight of 1,000 or more, succinonitrile, or cyclic phosphate. And a mixture of one or more of them. In the present invention, ethylene carbonate has a melting point of about 37°C, polyethylene glycol (Mw 1000 or more) is about 35°C, succinonitrile has a melting point of about 57°C, and cyclic phosphate has a melting point of about 65°C. [74] On the other hand, propylene carbonate (PC), polyethylene glycol (PEG) having a weight average molecular weight of less than 1,000, especially 600 or less, polyethylene glycol dimethyl ether (PEGDME), and diethylphthalate Phthalate, DEP), etc., are materials used as organic solvents for liquid electrolytes, or exist in a liquid state at room temperature, and thus, are not applied as filling materials of the present invention. [75] In a specific embodiment of the present invention, the filling material may be ethylene carbonate. The ethylene carbonate has a melting point of about 37° C. and exists in a solid state at room temperature. Ethylene carbonate is liquefied under a temperature condition equal to or higher than the melting point, and liquefied ethylene carbonate can function as a liquid electrolyte by dissolving the surrounding solid lithium salt, and has the advantage of less mixing of impurities. In particular, such ethylene carbonate has high ion conductivity and oxidation reactivity (6.2V) in the non-aqueous electrolyte solution, and is helpful in improving the performance of the battery after forming the SEI film. [76] On the other hand, in one embodiment of the present invention, the lithium salt concentration in the liquefied filler material may be about 0.05 mol% (mol%) to 5.0 mol%, and within the above range, 0.1 mol% or more, 0.5 mol% or more, 1.0 mol % Or more or 2.0 mol% or more, and within the above range, 4.0 mol% or less, 3.0 mol% or less, or 2.0 mol% or less. For example, the concentration of the lithium salt may be 0.1% to 2.5 mol%, 1.5 mol% to 2.5 mol%, or 1.0 mol% to 2.0 mol%. [77] When the concentration of the lithium salt satisfies the above numerical range, the liquefied filler material may not be solidified again even if the temperature is lowered later. In addition, when the concentration of the lithium salt satisfies the above numerical range, the viscosity of the lithium salt in the liquefied mixture is appropriately maintained, resulting in lower low-temperature output, which may be advantageous in terms of economy. In addition, if it is within the above numerical range, it may have an ionic conductivity suitable for use as a liquid electrolyte, and may have a concentration suitable for reducing interface resistance with an electrode. 1B is a schematic diagram showing a state in which the filling material of the phase change layer is liquefied. Referring to this, referring to this, a phase change layer 130 and an electrolyte layer 40 are interposed between the anode 110 and the cathode 120, and the phase change layer is disposed to face the anode. Here, the phase change layer 130 has a state 130a in which the filling material is liquefied according to an increase in the internal temperature of the battery. [78] On the other hand, in one embodiment of the present invention, the electrolyte layer may be coated with a lithium salt in all or at least a portion of the one side of the surface that faces the phase change layer. As described above, when the filling material is liquefied and then mixed with a lithium salt, the liquefied state is maintained even when the temperature is lowered. Accordingly, the molten filler material can be easily mixed with the lithium salt by coating the lithium salt on the surface of the electrolyte layer. In addition, in another embodiment of the present invention, in particular, in the case of using a polymer-based solid electrolyte as a solid electrolyte material, a polymer resin layer is formed without mixing the polymer resin and lithium salt, and then a lithium salt is coated on the surface thereof. An electrolyte layer can be formed by forming a lithium salt layer. The lithium salt can be used without limitation as long as it is mixed with the liquefied filler material and can exist in an ionized state, and the above contents may be referred to. [79] 2A shows an electrolyte layer and a phase change layer 230 interposed between the positive electrode 210 and the negative electrode 220, wherein the electrolyte layer is a polymer resin layer 240 and a lithium salt layer 250 are sequentially stacked. The structure of the composite electrolyte membrane and the battery 200 including the lithium salt layer 250 to face the phase change layer 230 are schematically shown. Here, the polymer resin layer may or may not contain a lithium salt. The lithium salt layer is formed to cover all or at least part of the surface of the polymer resin layer with a lithium salt. [80] As described above, in the composite electrolyte membrane according to the present invention, as the temperature increases, such as an increase in internal temperature during battery charging and discharging, the filling material is melted and liquefied. Referring to FIG. 2B, the filling material is liquefied (230a, 250a), and the liquefied filling material fills the phase change layer 230. [81] Thereafter, the filling material liquefied by dissolving the surrounding lithium salt and the lithium salt are mixed, so that even if the temperature decreases, the filling material is not solidified again, and the liquid state can be maintained. The liquefied filling material may reduce the interface resistance between the electrode and the composite electrolyte membrane by performing a role as a liquid electrolyte by mixing a lithium salt. In addition, the resulting liquid electrolyte fills not only the pores of the porous sheet, but also the dead space between the composite electrolyte membrane and the electrode, thereby removing a dead space without ion conductivity, thereby improving ionic conductivity. There is an effect of improving the adhesion between the composite electrolyte membranes. [82] Meanwhile, in the present specification, the liquefied, liquefied, liquefied, and liquefied state may mean a state in which a solid filling material is melted to have fluidity. [83] [84] In addition, the present invention provides an all-solid-state battery including the composite electrolyte membrane. The all-solid-state battery has a positive electrode, a negative electrode, and the composite electrolyte membrane interposed between the positive electrode and the negative electrode, and preferably the phase change layer is disposed to face the positive electrode. [85] [86] In the present invention, the positive electrode includes a positive electrode current collector and a positive electrode active material layer including a positive electrode active material, a conductive material, and a solid electrolyte on at least one surface of the current collector. The positive electrode active material layer may further include a binder resin as necessary. The positive electrode active material may include a layered compound such as a lithium manganese composite oxide (LiMn 2 O 4 , LiMnO 2, etc.), a lithium cobalt oxide (LiCoO 2 ), or a lithium nickel oxide (LiNiO 2 ), or a compound substituted with one or more transition metals; Lithium manganese oxides such as the formula Li 1 + x Mn 2 - x O 4 (wherein x is 0 to 0.33), LiMnO 3 , LiMn 2 O 3 , and LiMnO 2 ; Lithium copper oxide (Li 2 CuO 2); Vanadium oxides such as LiV 3 O 8 , LiV 3 O 4 , V 2 O 5 , and Cu 2 V 2 O 7 ; Formula LiNi x Co y Mn z O2 (where x+y+z=1, 0