A continuously produced flexible composite solid electrolyte film and its preparation method

Abstract

The present invention provides a continuously producible flexible composite solid electrolyte film and a preparation method thereof. By using a vacuum filtration device to fill an inorganic solid electrolyte into a porous base membrane, and by regulating the pore coverage and pore area on the surface of the vacuum filtration device, as well as the speed difference between the base membrane and the vacuum filtration device, the inorganic solid electrolyte is fully and evenly filled into the porous base membrane, thereby improving the overall performance and stability of the solid electrolyte film. This preparation method is suitable for the industrial production of composite solid electrolyte films. It helps to overcome the shortcomings of the prior art, such as the lack of uniform distribution of inorganic solid electrolytes, weak bonding strength, poor flexibility, and disadvantages of continuous production.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery materials, and in particular relates to a flexible composite solid electrolyte film that can be produced continuously and a preparation method thereof. Background Art

[0002] With the growing demand for energy and increasing awareness of environmental protection, the development of new, efficient, and safe energy storage technologies has become increasingly important. While traditional liquid lithium-ion batteries are widely used in portable electronic devices and electric vehicles, they have limited energy density and pose safety risks such as flammability and leakage. Therefore, solid-state batteries, as a new energy storage technology, are widely considered a key development direction in the power battery field due to their high energy density, wide temperature resistance, and superior safety.

[0003] The core component of solid-state batteries is the solid electrolyte, which can be divided into inorganic solid electrolytes, polymer electrolytes, and composite solid electrolytes. Inorganic solid electrolytes are favored for their high ionic conductivity and wide electrochemical window, but their brittleness and poor contact with electrodes limit their application. Polymer electrolytes are known for their flexibility and good electrode contact, but their low ionic conductivity and poor mechanical and electrochemical stability are their disadvantages. Composite solid electrolytes combine the advantages of both and are considered to be the most promising electrolyte material for high-performance lithium batteries.

[0004] However, the main challenges currently faced are the uniform dispersion of inorganic fillers in the polymer matrix, the high mechanical strength of the composite solid electrolyte film, and large-scale production. Existing organic / inorganic composite solid electrolyte film preparation technologies, such as coating and doctor blade infusion methods, have achieved the preparation of composite solid electrolytes to a certain extent, but the mechanical properties of the prepared films are poor, and the inorganic components are prone to uneven dispersion, resulting in agglomeration. In addition, although the electrospinning method can obtain flexible composite films, its pores are large, the density is low, and the cost is high, making it difficult to achieve large-scale production. The commercial diaphragm substrate is mainly a polyolefin diaphragm, which is coated with a ceramic coating to improve heat resistance, but the control of coating thickness and the stability of the coating are also technical difficulties. The shedding of the ceramic coating will lead to problems such as increased internal resistance of the battery and poor cycle performance.

[0005] Therefore, how to ensure the uniform dispersion of inorganic fillers in the polymer matrix and improve the preparation process to facilitate the large-scale continuous production of composite solid electrolyte films remains a huge challenge and requires our continuous research. Summary of the Invention

[0006] The present invention addresses the problems of the prior art and discloses a continuously producible flexible composite solid electrolyte film and a method for preparing the same. In the preparation method of the present invention, a vacuum filtration device is used and the pore coverage and pore area on the surface of the vacuum filtration device, as well as the speed difference between the vacuum filtration device and the porous base membrane containing the inorganic solid electrolyte, are regulated to facilitate the full and uniform dispersion of the inorganic solid electrolyte in the porous base membrane, thereby producing a dense, complete, and continuously producible flexible composite solid electrolyte film.

[0007] The present invention is achieved through the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing a flexible composite solid electrolyte film that can be continuously produced; the preparation method comprises:

[0009] S1: Preliminary compounding of a mixed solution A containing an inorganic solid electrolyte with a porous base membrane in operation; the porous base membrane has a porosity of 50-90% and a thickness of no more than 200 microns;

[0010] S2: preparing a composite solid electrolyte film precursor by subjecting the preliminarily composited porous base membrane containing the inorganic solid electrolyte to a vacuum filtration device;

[0011] S3: drying and heat-treating the composite solid electrolyte film precursor described in S2 to obtain a flexible composite solid electrolyte film;

[0012] The vacuum filtration device and the porous base membrane containing an inorganic solid electrolyte are both in operation, the speed difference between the two is 0.3-2.5 m / min, the filtration pressure between the porous base membrane containing an inorganic solid electrolyte and the vacuum filtration device is 0.01-1 MPa; the pore coverage rate per unit area of ​​the vacuum filtration device is 70-95%, and the pore area range is 0.01-10 mm 2 .

[0013] As a further solution, the particle size of the inorganic solid electrolyte is 1-500 nanometers; the solid content of the mixed solution A is in the range of 1-50 wt %; and the pore size of the porous base membrane in S1 is selected from 1-500 nanometers.

[0014] Furthermore, the particle size of the inorganic solid electrolyte is preferably 50-200 nanometers; the pore size of the porous base membrane in S1 is preferably 250-400 nanometers.

[0015] The present invention does not limit the type of inorganic solid electrolyte; researchers in this field can select a suitable type of inorganic solid electrolyte according to specific needs; as some examples: the type of inorganic solid electrolyte is selected from one or more of oxide solid electrolytes, sulfide solid electrolytes, halide solid electrolytes, nitride solid electrolytes, phosphate solid electrolytes, and borate solid electrolytes; among which, the oxide solid electrolyte includes one or more of garnet-type solid electrolytes, perovskite-type solid electrolytes, or NASICON-type solid electrolytes. Garnet-type solid electrolytes include lithium lanthanum zirconium oxide (LLZO) or solid electrolytes obtained by element replacement, doping or modification of LLZO; perovskite-type solid electrolytes include lithium lanthanum titanium oxide (LLTO) or solid electrolytes obtained by element replacement, doping or modification of LLTO; NASICON-type solid electrolytes include lithium aluminum titanium phosphate (LATP) and lithium aluminum germanium phosphate (LAGP) or solid electrolytes obtained by element replacement, doping or modification of LATP or LAGP; sulfide solid electrolytes include LGPS or solid electrolytes obtained by element replacement, doping or modification of LGPS; halide solid electrolytes include Li2MnCl4 and Li2ZnCl4; nitride solid electrolytes include lithium nitride Li3N; phosphate solid electrolytes include lithium phosphate Li3PO4; and borate solid electrolytes include LiBO2 and Li4B2O5.

[0016] The present invention does not limit the type of porous base membrane; researchers in this field can select the appropriate type of porous base membrane according to specific needs; as some examples: the type of porous base membrane in S1 is selected from a polymer-based porous base membrane or a natural polymer-based porous base membrane; wherein the polymer-based porous base membrane includes one or more of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyurethane (PU), polyacrylonitrile (PAN), polyethylene oxide (PEO), polystyrene (PS), polyvinyl chloride (PVC), polycarbonate (PC), polymethyl methacrylate (PMMA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), a copolymer of vinylidene fluoride and hexafluoropropylene (PVDF-HFP), and polyimide (PI). The natural polymer-based porous base membrane is selected from cellulose membrane and its derivatives.

[0017] As a further solution, the mixed solution A in S1 includes a solvent; the type of the solvent is selected from one or more of water, ethanol, isopropanol, glycerol, ethylene glycol, tetrahydrofuran, N,N-dimethylformamide, and N-methylpyrrolidine.

[0018] In principle, this application does not limit the specific structural composition of the vacuum filtration device; technical personnel in this field can use equipment of different shapes and structures to perform vacuum filtration to prepare composite solid electrolyte films as needed; as a preferred specific implementation case: the vacuum filtration device in S2 is selected from one of a roller-shaped vacuum filtration device or a parallel box-type vacuum filtration device.

[0019] As a further embodiment, the roller-shaped vacuum filtration device includes a vacuum filtration roller for adsorbing a porous basement membrane containing an inorganic solid electrolyte; the vacuum filtration roller is internally provided with a first rotating shaft for driving its rotation; and the surface of the vacuum filtration roller further has a first suction hole, which is used to realize the device's vacuum filtration function on the porous basement membrane containing an inorganic solid electrolyte. The rotation of the first rotating shaft drives the movement of the vacuum filtration roller, thereby generating a suitable speed difference with the moving porous basement membrane containing an inorganic solid electrolyte during continuous production, thereby promoting sufficient and uniform adsorption of the inorganic solid electrolyte within the porous basement membrane.

[0020] As a further solution, the roller-shaped vacuum filtration device also includes a flexible covering film; the flexible covering film is adsorbed on the surface of the vacuum filtration roller through a second rotating shaft; it is used to cover the part of the vacuum filtration roller that does not contact the porous base membrane containing the inorganic solid electrolyte; it further improves the negative pressure retention rate of the roller-shaped vacuum filtration device, has a good vacuum adsorption effect on the porous base membrane containing the inorganic solid electrolyte, ensures that the inorganic solid electrolyte is fully, evenly and stably embedded in the porous base membrane, and prepares a flexible composite solid electrolyte film with better performance that can be continuously produced.

[0021] As a further solution, the parallel box-type vacuum filtration device includes a vacuum filtration box for adsorbing a porous base membrane containing an inorganic solid electrolyte; the surface of the vacuum filtration box has a second suction hole; used to realize the vacuum filtration function of the device on the porous base membrane containing an inorganic solid electrolyte; a third rotating shaft is provided on each side of the vacuum filtration box for driving the porous base membrane containing an inorganic solid electrolyte to move.

[0022] The present invention does not specifically limit the way in which the parallel box-type vacuum filtration device realizes movement, and researchers in this field can choose according to specific needs; as some specific examples: the present invention chooses to set a mobile platform at the bottom of the vacuum filtration box to realize the movement of the vacuum filtration device; and then realizes the preparation of flexible composite solid electrolyte film during the production process.

[0023] In principle, the present invention does not impose any specific restrictions on the specific shapes of the first air exhaust hole and the second air exhaust hole. Those skilled in the art can select air exhaust holes of appropriate shapes according to their needs. As some specific examples: the first air exhaust hole and the second air exhaust hole can be selected from circular, square, elliptical, etc.

[0024] As a further embodiment, the operating speed of the vacuum filtration device is selected from 0.1-10 m / min, and the speed difference with the porous base membrane containing the inorganic solid electrolyte is preferably 0.5-2 m / min. The pore coverage rate per unit area of ​​the vacuum filtration device is preferably 75-90%, and the range of pore area is preferably 0.1-10 mm 2 .

[0025] As a further solution, the drying temperature in S3 is selected from 60-100 degrees, and the drying time is selected from 6-24 hours.

[0026] As a further solution, the heat treatment method in S3 is selected from one of hot pressing or roller pressing; the pressure range is 20-50kg / cm 2 , temperature is 50-130 degrees, time is 1-15 minutes.

[0027] The present invention does not specifically limit the method for preliminary compounding of the mixed solution A in S1 and the porous base membrane. Those skilled in the art can select a suitable preliminary compounding method according to their needs; as an exemplary description, the method for preliminary compounding can be selected from one of a coating process and an immersion process.

[0028] In a second aspect, the present invention provides a flexible composite solid electrolyte film that can be produced continuously; the film is prepared by the preparation method of the first aspect; the film has a thickness of 10-40 μm and a tensile strength of 10-80 MPa.

[0029] In a third aspect, the present invention provides a battery or energy storage device, wherein the battery or energy storage device comprises the flexible composite solid electrolyte film described in the second aspect.

[0030] The characteristics and beneficial effects of the present invention are:

[0031] (1) The present invention adopts a vacuum filtration method to uniformly fill the inorganic solid electrolyte solution into the pores of the porous base membrane, and ensures the flatness of the porous base membrane by regulating the pore coverage and pore area on the surface of the vacuum filtration device, which helps to achieve a good balance between the effective support and adsorption effect of the vacuum filtration device on the porous base membrane; and improves the uniform dispersion of the inorganic solid electrolyte in the porous base membrane.

[0032] (2) The present invention also regulates the speed difference between the vacuum filtration device and the porous base membrane during operation. By regulating the appropriate speed difference, it helps to avoid the problem of poor vacuum filtration effect caused by the porous base membrane running too fast or too slow during production and preparation, and is more suitable for the industrial production of composite solid electrolyte membranes. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 It is a schematic diagram of a roller-shaped vacuum filtration device; Figure 1 (1) is a top view of a roller-shaped vacuum filtration device with a circular hole. Figure 1 (2) is a top view of the operation of a roller-shaped vacuum filtration device with square holes, Figure 1 (3) is a front view schematic diagram of the operation of the roller-shaped vacuum filtration device.

[0035] Figure 2 It is a schematic diagram of a parallel box type vacuum filtration device; Figure 2 (1) is a top view of a parallel box type vacuum filtration device with circular holes. Figure 2 (2) is a top view of a parallel box type vacuum filtration device with square holes. Figure 2 (3) is a front view schematic diagram of the operation of the parallel box type vacuum filtration device.

[0036] Reference numerals:

[0037] 1-vacuum filtration roller; 2-first rotating shaft; 3-first air extraction hole; 4-flexible covering membrane; 5-vacuum filtration box; 6-second air extraction hole; 7-third rotating shaft; 8-movable platform; 9-second rotating shaft. DETAILED DESCRIPTION

[0038] In order to facilitate understanding of the present invention, the present invention will be described in more detail below, and embodiments of the present invention are given, but the scope of the present invention is not limited thereby.

[0039] In a first aspect, the present invention provides a method for preparing a flexible composite solid electrolyte film that can be continuously produced; the preparation method comprises:

[0040] S1: Preliminary compounding of a mixed solution A containing an inorganic solid electrolyte with a porous base membrane in operation; the porous base membrane has a porosity of 50-90% and a thickness of no more than 200 microns;

[0041] S2: preparing a composite solid electrolyte film precursor by subjecting the preliminarily composited porous base membrane containing the inorganic solid electrolyte to a vacuum filtration device;

[0042] S3: drying and heat-treating the composite solid electrolyte film precursor described in S2 to obtain a flexible composite solid electrolyte film;

[0043] The vacuum filtration device and the porous base membrane containing an inorganic solid electrolyte are both in operation, the speed difference between the two is 0.3-2.5 m / min, the filtration pressure between the porous base membrane containing an inorganic solid electrolyte and the vacuum filtration device is 0.01-1 MPa; the pore coverage rate per unit area of ​​the vacuum filtration device is 70-95%, and the pore area range is 0.01-10 mm 2 .

[0044] In order to solve the problems that the inorganic solid electrolyte cannot be evenly distributed, the bonding force is weak, and the coating layer is prone to falling off during the preparation process of the composite solid electrolyte film; and the shortcomings of the composite solid electrolyte film prepared in the prior art are relatively thick, poor flexibility, and not conducive to continuous production; the present application has conducted a new preparation process research and chose to use vacuum filtration to evenly fill the prepared inorganic solid electrolyte solution into the pores of the porous base membrane; especially in the continuous production process, by controlling the pore distribution and size of the vacuum filtration device, the porous base membrane is used as a supporting skeleton to ensure that the porous base membrane containing the inorganic solid electrolyte is fully fitted with the vacuum filtration device; and the speed difference between the porous base membrane containing the inorganic solid electrolyte and the vacuum filtration device is regulated to ensure that the inorganic solid electrolyte can be fully filled into the porous base membrane under vacuum filtration, avoiding the generation of uneven dispersion of the inorganic solid electrolyte inside the porous base membrane, thereby ensuring that the porous base membrane has both flexibility and good mechanical strength. Finally, through dry heat treatment, the thickness of the flexible composite solid electrolyte film is further reduced, making the contact between the inorganic solid electrolyte particles closer, forming a continuous lithium ion transmission path, thereby improving the ionic conductivity of the film and obtaining a dense, complete, and continuously producible flexible composite solid electrolyte film.

[0045] Compared with the prior art, the present invention adopts a simple preparation process by vacuum filtration, and in order to ensure that the inorganic solid electrolyte is fully and evenly dispersed in the porous basement membrane, the present application fully regulates the speed difference between the vacuum filtration device and the porous basement membrane containing the inorganic solid electrolyte during the production and preparation process, as well as the distribution of the pore area and pore coverage of the vacuum filtration device surface; Specifically, we adjust the speed difference between the vacuum filtration device and the porous basement membrane containing the inorganic solid electrolyte, and further optimize the pore distribution and pore coverage on the surface of the vacuum filtration device. By accurately regulating the pore coverage and pore size per unit area of ​​the vacuum filtration device, it is beneficial to maintain the flatness of the porous basement membrane containing the inorganic solid electrolyte during the vacuum filtration process, thereby achieving a good balance between the effective support and adsorption of the porous basement membrane; it is beneficial to improve the uniform dispersion of the inorganic solid electrolyte in the porous basement membrane.

[0046] At the same time, this application also fine-tunes the speed difference between the vacuum filtration device and the porous base membrane containing the inorganic solid electrolyte, aiming to avoid the poor vacuum filtration effect caused by the excessively fast or slow movement of the porous base membrane containing the inorganic solid electrolyte during the production and preparation process, as well as the uneven distribution of the inorganic solid electrolyte caused by this. By optimizing and adjusting the above parameters, it is possible to ensure that the inorganic solid electrolyte is evenly distributed in the porous base membrane, thereby improving the overall performance and stability of the solid electrolyte film; it is more suitable for the industrial production of composite solid electrolyte films.

[0047] As a further solution, the particle size of the inorganic solid electrolyte is 1-500 nanometers; the solid content of the mixed solution A is in the range of 1-50 wt %; and the pore size of the porous base membrane in S1 is selected from 1-500 nanometers.

[0048] The appropriate solid content range in the mixed solution helps to achieve a uniform dispersion effect when compounded with the porous base membrane, while avoiding the problem of porous base membrane clogging caused by excessively high solid content. In addition, by precisely controlling the particle size of the inorganic solid electrolyte and the pore size of the porous base membrane, the distribution uniformity of the inorganic solid electrolyte in the porous base membrane can be effectively controlled during the production process, and the compounding efficiency can be improved; thus, a flexible composite solid electrolyte film with excellent electrochemical and mechanical properties can be prepared.

[0049] Furthermore, the particle size of the inorganic solid electrolyte is preferably 50-200 nanometers; the pore size of the porous base membrane in S1 is preferably 250-400 nanometers.

[0050] The present invention does not limit the type of inorganic solid electrolyte; researchers in this field can select a suitable type of inorganic solid electrolyte according to specific needs; as some examples: the type of inorganic solid electrolyte is selected from one or more of oxide solid electrolytes, sulfide solid electrolytes, halide solid electrolytes, nitride solid electrolytes, phosphate solid electrolytes, and borate solid electrolytes; among which, the oxide solid electrolyte includes one or more of garnet-type solid electrolytes, perovskite-type solid electrolytes, or NASICON-type solid electrolytes. Garnet-type solid electrolytes include lithium lanthanum zirconium oxide (LLZO) or solid electrolytes obtained by element replacement, doping or modification of LLZO; perovskite-type solid electrolytes include lithium lanthanum titanium oxide (LLTO) or solid electrolytes obtained by element replacement, doping or modification of LLTO; NASICON-type solid electrolytes include lithium aluminum titanium phosphate (LATP) and lithium aluminum germanium phosphate (LAGP) or solid electrolytes obtained by element replacement, doping or modification of LATP or LAGP; sulfide solid electrolytes include LGPS or solid electrolytes obtained by element replacement, doping or modification of LGPS; halide solid electrolytes include Li2MnCl4 and Li2ZnCl4; nitride solid electrolytes include lithium nitride Li3N; phosphate solid electrolytes include lithium phosphate Li3PO4; and borate solid electrolytes include LiBO2 and Li4B2O5.

[0051] The present invention does not limit the type of porous base membrane; researchers in this field can select the appropriate type of porous base membrane according to specific needs; as some examples: the type of porous base membrane in S1 is selected from a polymer-based porous base membrane or a natural polymer-based porous base membrane; wherein the polymer-based porous base membrane includes one or more of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyurethane (PU), polyacrylonitrile (PAN), polyethylene oxide (PEO), polystyrene (PS), polyvinyl chloride (PVC), polycarbonate (PC), polymethyl methacrylate (PMMA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), a copolymer of vinylidene fluoride and hexafluoropropylene (PVDF-HFP), and polyimide (PI). The natural polymer-based porous base membrane is selected from cellulose membrane and its derivatives.

[0052] As a further solution, the mixed solution A in S1 includes a solvent; the type of the solvent is selected from one or more of water, ethanol, isopropanol, glycerol, ethylene glycol, tetrahydrofuran, N,N-dimethylformamide, and N-methylpyrrolidine.

[0053] In principle, this application does not limit the specific structure of the vacuum filtration device; those skilled in the art may use equipment of different shapes and structures to perform vacuum filtration to prepare the composite solid electrolyte film as needed. As a preferred embodiment, the vacuum filtration device in S2 is selected from a roller-shaped vacuum filtration device or a parallel box-type vacuum filtration device. The vacuum filtration device and the porous base membrane are controlled by independent moving conveyors to achieve speed difference movement.

[0054] The porous base film is a rollable film, and its movement can be controlled by a front and rear conveying device, which can be selected from conventional conveying devices such as rollers that move back and forth.

[0055] like Figure 1 As shown; as a further embodiment, the roller-shaped vacuum filtration device includes a vacuum filtration roller 1 for adsorbing a porous base membrane containing an inorganic solid electrolyte; the vacuum filtration roller 1 is provided with a first rotating shaft 2 for driving its rotation; the surface of the vacuum filtration roller 1 also has a first suction hole 3, which is used to realize the device's vacuum filtration function on the porous base membrane containing an inorganic solid electrolyte. The rotation of the first rotating shaft 2 drives the movement of the vacuum filtration roller 1, thereby generating a suitable speed difference with the moving porous base membrane containing an inorganic solid electrolyte during the continuous production process, thereby promoting sufficient and uniform adsorption of the inorganic solid electrolyte within the porous base membrane.

[0056] As a further solution, the roller-shaped vacuum filtration device also includes a flexible covering membrane 4; the flexible covering membrane 4 is adsorbed on the surface of the vacuum filtration roller 1 through the second rotating shaft 9; it is used to cover the part of the vacuum filtration roller 1 that does not contact the porous base membrane containing the inorganic solid electrolyte; further improve the negative pressure retention rate of the roller-shaped vacuum filtration device, and have a good vacuum adsorption effect on the porous base membrane containing the inorganic solid electrolyte, ensuring that the inorganic solid electrolyte is fully, evenly and stably embedded in the porous base membrane, and preparing a flexible composite solid electrolyte film with better performance that can be continuously produced.

[0057] like Figure 2 As shown, as a further solution, the parallel box-type vacuum filtration device includes a vacuum filtration box 5 for adsorbing a porous base membrane containing an inorganic solid electrolyte; the surface of the vacuum filtration box 5 has a second suction hole 6; it is used to realize the vacuum filtration function of the device on the porous base membrane containing an inorganic solid electrolyte; a third rotating shaft 7 is provided on each side of the vacuum filtration box 5 for driving the porous base membrane containing an inorganic solid electrolyte to move.

[0058] The present invention does not specifically limit the manner in which the parallel box-type vacuum filtration device realizes movement, and researchers in this field can make choices based on specific needs. As some specific examples: the present invention chooses to set a movable platform 8 at the bottom of the vacuum filtration box 5 to realize the movement of the vacuum filtration device; thereby realizing the preparation of a flexible composite solid electrolyte film during the production process.

[0059] In principle, the present invention does not impose any specific restrictions on the specific shapes of the first air extraction hole 3 and the second air extraction hole 6. Those skilled in the art can select air extraction holes of appropriate shapes according to their needs. As some specific examples: the first air extraction hole 3 and the second air extraction hole 6 can be selected from circular, square, elliptical, etc.

[0060] As a further embodiment, the operating speed of the vacuum filtration device is selected from 0.1-10 m / min, and the speed difference with the porous base membrane containing the inorganic solid electrolyte is preferably 0.5-2 m / min. The pore coverage rate per unit area of ​​the vacuum filtration device is preferably 75-90%, and the range of pore area is preferably 0.1-10 mm 2 .

[0061] This application further regulates the speed difference between the vacuum filtration device and the porous base membrane containing an inorganic solid electrolyte during the production and preparation process, as well as the distribution of the pore area and pore coverage on the surface of the vacuum filtration device. The purpose is to achieve a good balance between its support and adsorption effect on the porous base membrane by regulating the pore coverage and pore area per unit area of ​​the vacuum filtration device, thereby achieving tight adsorption while maintaining the structural integrity of the porous base membrane; promoting the full integration of the inorganic solid electrolyte inside the porous base membrane; at the same time, this application further regulates the speed difference between the vacuum filtration device and the porous base membrane containing an inorganic solid electrolyte; the speed difference within the optimized range helps to achieve the best vacuum filtration effect in the continuous production process, ensuring the formation of a denser flexible composite solid electrolyte film.

[0062] As a further solution, the drying temperature in S3 is selected from 60-100 degrees, and the drying time is selected from 6-24 hours.

[0063] As a further solution, the heat treatment method in S3 is selected from one of hot pressing or roller pressing; the pressure range is 20-50kg / cm 2 , temperature is 50-130 degrees, time is 1-15 minutes.

[0064] Selecting the appropriate heat treatment pressure and temperature can help further reduce the thickness of the flexible composite solid electrolyte film, promote the close bonding between the inorganic solid electrolyte and the porous base membrane, and build a more continuous and uniform ion transmission path, thereby improving the ion conductivity during the battery charge and discharge cycle. In addition, it can further enhance the mechanical strength of the flexible composite solid electrolyte film and ensure its stability and reliability during battery assembly and use. Through further heat treatment and optimization of heat treatment conditions, the pores and defects after the inorganic solid electrolyte is filled in the film can be effectively reduced, and a more stable interface can be formed between the inorganic solid electrolyte and the porous base membrane, which is crucial for improving the cycle life and safety of the battery.

[0065] The present invention does not specifically limit the method for preliminary compounding of the mixed solution A in S1 and the porous base membrane. Those skilled in the art can select a suitable preliminary compounding method according to their needs; as an exemplary description, the method for preliminary compounding can be selected from one of a coating process and an immersion process.

[0066] In a second aspect, the present invention provides a flexible composite solid electrolyte film that can be produced continuously; the film is prepared by the preparation method of the first aspect; the film has a thickness of 10-40 μm and a tensile strength of 10-80 MPa.

[0067] The flexible composite solid electrolyte film that can be continuously produced obtained by the preparation process of the present invention has a lower thickness and better tensile strength; the composite method of filling the inorganic solid electrolyte inside the porous base membrane is more stable, which helps to have good adaptability and cycle durability in the battery's charge and discharge cycle; at the same time, the lower thickness helps to reduce the ion transmission resistance, thereby improving the ion migration rate and the battery's charge and discharge performance.

[0068] In a third aspect, the present invention provides a battery or energy storage device, wherein the battery or energy storage device comprises the flexible composite solid electrolyte film described in the second aspect.

[0069] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0070] The chemical raw materials involved in the following examples and comparative examples are all prior art and commercially available. The experimental devices, test devices, etc. involved in the following examples and comparative examples are all conventional devices in the art and are not particularly limited.

[0071] Example 1

[0072] The LATP inorganic solid electrolyte with a particle size of 50 nanometers was uniformly dispersed in NMP solvent to prepare a mixed solution A, wherein the solid content in the mixed solution A was 10 wt%;

[0073] Polyethylene PE material is selected as the porous base membrane, with a porosity of 70%, a pore size of about 300 nanometers, and a thickness of 30 μm;

[0074] The mixed solution A is preliminarily compounded with the PE porous base membrane by coating;

[0075] The LATP particles are vacuum filtered into the pores of the PE porous base membrane by a parallel box-type vacuum filtration device to obtain a composite solid electrolyte film precursor; wherein, the running speed V1 of the inorganic solid electrolyte porous base membrane after the initial composite is 1m / min, the running speed V2 of the vacuum filtration box 5 is 1.5m / min, and the filtration pressure on the surface of the inorganic solid electrolyte porous base membrane and the vacuum filtration box 5 is 0.1MPa; the surface pore coverage rate of the parallel box-type vacuum filtration device is 80%, and the pore area is 2mm 2 .

[0076] The composite solid electrolyte film precursor was dried in an oven at 80°C for 12 h to remove the residual solvent in the film;

[0077] The dried film was hot pressed at a pressure of 30 kg / cm 2 , temperature is 80 degrees, and holding time is 10 minutes; the obtained flexible composite solid electrolyte film has a thickness of 20 μm and a tensile strength of 20 MPa.

[0078] Example 2

[0079] The specific preparation method and steps are the same as those in Example 1, except that: the LATP particles are vacuum filtered into the pores of the PE porous base membrane through a roller-shaped vacuum filtration device to obtain a composite solid electrolyte film precursor; wherein, after the initial composite, the running speed V1 of the inorganic solid electrolyte porous base membrane is 1m / min, the running speed V2 of the vacuum filtration roller 1 is 1.5m / min, and the filtration pressure between the inorganic solid electrolyte porous base membrane and the vacuum filtration roller 1 is 0.1MPa. The surface pore coverage of the roller-shaped vacuum filtration device is 80%, and the pore area is 2mm 2 .

[0080] Example 3

[0081] The specific preparation steps and methods are the same as those in Example 1, except that the surface pore coverage of the parallel box-type vacuum filtration device is 85%, and the pore area is 1.5 mm 2 .

[0082] Example 4

[0083] The specific preparation steps and methods are the same as those in Example 2, except that: the surface pore coverage of the roller-shaped vacuum filtration device is 85% and the pore area is 3mm 2 .

[0084] Example 5

[0085] LLTO inorganic solid electrolyte with a particle size of 150 nanometers was uniformly dispersed in NMP solvent to prepare a mixed solution A, wherein the solid content in the mixed solution A was 5 wt%;

[0086] Polyethylene PE material is selected as the porous base membrane, with a porosity of 80%, a pore size of about 300 nanometers, and a thickness of 30 μm;

[0087] The mixed solution A is preliminarily compounded with the PE porous base membrane by coating;

[0088] The LATP particles are vacuum filtered into the pores of the PE porous base membrane by a parallel box-type vacuum filtration device to obtain a composite solid electrolyte film precursor; wherein, the running speed V1 of the porous base membrane containing the inorganic solid electrolyte after the initial composite is 0.1m / min, the running speed V2 of the vacuum filtration box 5 is 0.6m / min, and the filtration pressure on the surface of the porous base membrane containing the inorganic solid electrolyte and the vacuum filtration box 5 is 0.08MPa; the surface pore coverage rate of the parallel box-type vacuum filtration device is 80%, and the pore area is 2mm 2 .

[0089] The composite solid electrolyte film precursor was dried in an oven at 80°C for 12 h to remove the residual solvent in the film;

[0090] The dried film was hot pressed at a pressure of 30 kg / cm 2 , temperature is 80 degrees, and holding time is 10 minutes; the obtained flexible composite solid electrolyte film has a thickness of 20 μm and a tensile strength of 50 MPa.

[0091] Example 6

[0092] LLZO inorganic solid electrolyte with a particle size of 50 nanometers is uniformly dispersed in NMP solvent to prepare a mixed solution A, wherein the solid content in the mixed solution A is 20 wt%;

[0093] Polyethylene PE material is selected as the porous base membrane, with a porosity of 80%, a pore size of about 300 nanometers, and a thickness of 80 μm;

[0094] The mixed solution A is preliminarily compounded with the PE porous base membrane by coating;

[0095] The LATP particles are vacuum filtered into the pores of the PE porous base membrane by a parallel box-type vacuum filtration device to obtain a composite solid electrolyte film precursor; wherein, the running speed V1 of the inorganic solid electrolyte porous base membrane after the initial composite is 8m / min, the running speed V2 of the vacuum filtration box 5 is 10m / min, and the filtration pressure on the surface of the inorganic solid electrolyte porous base membrane and the vacuum filtration box 5 is 1MPa; the surface pore coverage rate of the parallel box-type vacuum filtration device is 80%, and the pore area is 2mm 2 .

[0096] The composite solid electrolyte film precursor was dried in an oven at 80°C for 12 h to remove the residual solvent in the film;

[0097] The dried film was hot pressed at a pressure of 30 kg / cm 2 , temperature is 80 degrees, and holding time is 10 minutes; the obtained flexible composite solid electrolyte film has a thickness of 40 μm and a tensile strength of 80 MPa.

[0098] Example 7

[0099] The LATP inorganic solid electrolyte with a particle size of 50 nanometers was uniformly dispersed in NMP solvent to prepare a mixed solution A, wherein the solid content in the mixed solution A was 25 wt%;

[0100] Polypropylene (PP) material was selected as the porous base membrane, with a porosity of 60%, a pore size of approximately 300 nanometers, and a thickness of 30 μm.

[0101] The mixed solution A is preliminarily compounded with the PE porous base membrane by coating;

[0102] The LATP particles are vacuum filtered into the pores of the PE porous base membrane by a parallel box-type vacuum filtration device to obtain a composite solid electrolyte film precursor; wherein, the running speed V1 of the porous base membrane containing the inorganic solid electrolyte after the initial composite is 0.8m / min, the running speed V2 of the vacuum filtration box 5 is 1.5m / min, and the filtration pressure on the surface of the porous base membrane containing the inorganic solid electrolyte and the vacuum filtration box 5 is 0.08MPa; the surface pore coverage rate of the parallel box-type vacuum filtration device is 80%, and the pore area is 2mm 2 .

[0103] The composite solid electrolyte film precursor was dried in an oven at 80°C for 12 h to remove the residual solvent in the film;

[0104] The dried film was hot pressed at a pressure of 40 kg / cm 2 , temperature is 80 degrees, and holding time is 10 minutes; the obtained flexible composite solid electrolyte film has a thickness of 15 μm and a tensile strength of 15 MPa.

[0105] Example 8

[0106] The LATP inorganic solid electrolyte with a particle size of 50 nanometers was uniformly dispersed in NMP solvent to prepare a mixed solution A, wherein the solid content in the mixed solution A was 30 wt%;

[0107] Polyethylene PE material is selected as the porous base membrane, with a porosity of 80%, a pore size of about 350 nanometers, and a thickness of 30 μm;

[0108] The mixed solution A is preliminarily compounded with the PE porous base membrane by coating;

[0109] The LATP particles are vacuum filtered into the pores of the PE porous base membrane by a parallel box-type vacuum filtration device to obtain a composite solid electrolyte film precursor; wherein, the running speed V1 of the inorganic solid electrolyte porous base membrane after the initial composite is 1m / min, the running speed V2 of the vacuum filtration box 5 is 1.5m / min, and the filtration pressure on the surface of the inorganic solid electrolyte porous base membrane and the vacuum filtration box 5 is 0.1MPa; the surface pore coverage rate of the parallel box-type vacuum filtration device is 80%, and the pore area is 2mm 2 .

[0110] The composite solid electrolyte film precursor was dried in an oven at 80°C for 12 h to remove the residual solvent in the film;

[0111] The dried film was hot pressed at a pressure of 50 kg / cm 2 , temperature is 80 degrees, and holding time is 10 minutes; the obtained flexible composite solid electrolyte film has a thickness of 15 μm and a tensile strength of 10 MPa.

[0112] Comparative Example 1

[0113] The specific steps and preparation method are the same as those in Example 1, except that the running speed V1 of the porous base membrane containing the inorganic solid electrolyte after the initial compounding is 10 m / min, and the running speed V2 of the vacuum filtration box 5 is 2 m / min.

[0114] Comparative Example 2

[0115] The specific steps and preparation method are the same as those in Example 1, except that: the surface pore coverage of the parallel box-type vacuum filtration device is 95%, and the pore area is 20mm 2 .

[0116] Comparative Example 3

[0117] The specific steps and preparation method are the same as those in Example 1, except that polyethylene (PE) material is selected as the porous base membrane, with a porosity of 70%, a pore size of approximately 100 nanometers, and a thickness of 300 μm.

[0118] Comparative Example 4

[0119] The specific steps and preparation method are the same as those in Example 1, except that: LATP inorganic solid electrolyte with a particle size of 50 nanometers is uniformly dispersed in NMP solvent to prepare mixed solution A, wherein the solid content in mixed solution A is 60 wt%.

[0120] Comparative Example 5

[0121] The specific steps and preparation method are the same as those in Example 1, except that the filtration pressure between the porous base membrane containing the inorganic solid electrolyte and the vacuum filtration device is 5 MPa.

[0122] Comparative Example 6

[0123] The specific steps and preparation method are the same as those in Example 1, except that the dried film is subjected to hot pressing at a pressure of 70 kg / cm 2 , temperature is 150 degrees, and holding time is 5 minutes; the obtained flexible composite solid electrolyte film has a thickness of 8 μm and a tensile strength of 5 MPa.

[0124] Specific test methods and conditions:

[0125] Ionic conductivity: EIS was measured using the AC impedance spectroscopy method with an amplitude of 10 mV and a frequency of 0.1 to 700,0000 Hz.

[0126] Cycle test: the positive electrode is LiNi 0.8 Co 0.1 Mn 0.1 The (NCM811) positive electrode is prepared by mixing 84wt.% NCM811, 8wt.% conductive carbon black (SP) and 8wt.% polyvinylidene fluoride (PVDF), and the negative electrode uses a lithium metal negative electrode. In an argon atmosphere glove box, the positive electrode shell, 811 positive electrode sheet, and the composite diaphragm are placed in this order. 60μL of lithium-ion secondary battery electrolyte is dripped onto the diaphragm, and then the lithium sheet, steel sheet, shrapnel and negative electrode shell are placed in this order. The battery is packaged and pressurized to 350MPa to obtain a button cell. The battery was subjected to a 1C rate charge and discharge test at 25±2℃ (room temperature), and the charge and discharge cut-off voltage was 3.0V-4.3V.

[0127] Table 1

[0128]

[0129] It can be seen from the data in Table 1 that the continuously produced composite solid electrolyte films prepared by the preparation process of Examples 1-8 using the present invention have better tensile strength, electrochemical properties and cycle stability than those of Comparative Examples 1-6; this indicates that the present invention utilizes vacuum filtration and regulates the process and material parameters such as the pore coverage, pore area, and speed of the inorganic solid electrolyte particles, the pores of the porous base membrane, and the vacuum filtration device, which helps to evenly disperse the inorganic solid electrolyte into the porous base membrane material; thus, it is suitable for obtaining a composite solid electrolyte film having both flexibility and mechanical strength in a continuous production process; and exhibits good battery charge and discharge performance and cycle stability during the battery charge and discharge process.

[0130] It can be seen from Example 1 and Comparative Example 1 that the tensile strength of the composite solid electrolyte membrane in Comparative Example 1 is low, and the ionic conductivity and cycle performance of the battery during the charge and discharge cycle are poor. We believe that this is due to the large difference in the operating rate between the porous basement membrane containing an inorganic solid electrolyte and the vacuum filtration housing 5, which causes the porous basement membrane to be unable to fully and evenly embed the inorganic solid electrolyte particles into the porous basement membrane during the composite process. The degree of vacuum filtration is insufficient, resulting in more residual inorganic solid electrolytes on the surface of the porous basement membrane. The prepared composite electrolyte membrane layer is thicker and is not conducive to forming a continuous and unobstructed ion transmission channel, thereby affecting the overall performance of the composite membrane. In Example 1, the operating rate difference within the optimization range ensures that the inorganic solid electrolyte particles are evenly distributed in the porous basement membrane, thereby improving the electrochemical properties and mechanical strength of the composite membrane.

[0131] It can be seen from Example 1 and Comparative Example 2 that the vacuum filtration device used in the present invention has different effects on the preparation of porous base membrane composite inorganic solid electrolytes when different suction hole areas are selected; the surface pore area used in the vacuum filtration device in Comparative Example 2 is too large than that in the embodiment, which can easily cause the porous base membrane to collapse when the porous base membrane is subjected to suction and adsorption, resulting in an uneven surface of the composite membrane, and the inorganic solid electrolyte particles cannot be evenly embedded in the porous base membrane, thereby affecting the electrochemical properties and mechanical strength of the composite membrane.

[0132] It can be seen from Example 1 and Comparative Example 3 that the selected porous base membrane is too thick, which is not conducive to the uniform dispersion of the inorganic solid electrolyte inside the porous base membrane, resulting in a decrease in the electrochemical performance and mechanical strength of the composite solid electrolyte membrane. In Comparative Example 3, the thickness of the porous base membrane is 300 μm, which is much larger than the thickness of the base membrane used in Example 1. Because the base membrane is too thick, the diffusion and distribution of the inorganic solid electrolyte particles inside the base membrane become difficult, resulting in uneven distribution of the electrolyte inside the composite membrane. This unevenness not only reduces the ionic conductivity of the electrolyte, but also weakens the mechanical strength of the composite membrane, making it easy to generate stress concentration during the battery charge and discharge process, thereby affecting the cycle stability and overall performance of the battery. In contrast, the thinner porous base membrane used in Example 1 contributes to the uniform dispersion of the inorganic solid electrolyte particles, thereby improving the electrochemical performance and mechanical strength of the composite membrane.

[0133] It can be seen from Example 1 and Comparative Example 4 that the composite solid electrolyte prepared in Comparative Example 4 has lower ionic conductivity and poorer cycle performance than that prepared in Example 1. This is because the solid content of the inorganic solid electrolyte in the mixed solution A is too high, resulting in an uneven distribution of the inorganic solid electrolyte inside the composite membrane when it is composited with the porous base membrane, and it is easy to form larger electrolyte particles during the drying process. These particles form defects in the composite membrane, destroying the pore structure of the porous base membrane and affecting the ion transmission efficiency. In addition, the mixed solution with a high solid content easily clogs the pores of the porous base membrane during the filtration process, further reducing the electrochemical performance and mechanical strength of the composite membrane, which is not conducive to having good cycle stability in the charge and discharge cycle of the battery.

[0134] It can be seen from Example 1 and Comparative Example 5 that, in the process of using vacuum filtration device to carry out suction filtration to the porous basement membrane containing inorganic solid electrolyte, the suction filtration pressure between the porous basement membrane containing inorganic solid electrolyte and the vacuum filtration device is 5MPa, and the adsorption pressure range optimized relative to the embodiment is too large, which easily leads to structural damage of the porous basement membrane, affecting the mechanical strength and electrochemical properties of the composite membrane. When the suction filtration pressure is too large, the pore structure of the porous basement membrane may be deformed or destroyed, making it impossible for the inorganic solid electrolyte particles to be evenly embedded in the porous basement membrane, thereby forming defects in the composite membrane, affecting the transmission efficiency of ions. In addition, too high suction filtration pressure may also cause the pores of the porous basement membrane to be blocked, further reducing the electrochemical properties and mechanical strength of the composite membrane, which is unfavorable for the cyclic stability in the battery charge and discharge cycle.

[0135] It can be seen from Example 1 and Comparative Example 6 that when the dried composite solid electrolyte membrane is further hot-pressed, the hot-pressing pressure and hot-pressing temperature used in Comparative Example 6 are larger than those in the embodiment. Although the composite solid electrolyte membrane layer obtained is lower than that in the embodiment, its tensile strength, ionic conductivity, cycle stability and other performances are poor. This is because when the hot-pressing pressure and temperature are too high, the inorganic solid electrolyte particles inside the composite membrane may aggregate, resulting in uneven electrolyte distribution. At the same time, excessive hot-pressing conditions may destroy the pore structure of the porous base membrane, affecting the continuity of the ion transmission channel. This uneven electrolyte distribution and the destruction of the pore structure not only reduce the electrochemical properties of the composite membrane, but also weaken its mechanical strength, thereby easily generating stress concentration during battery charge and discharge, affecting the cycle stability and overall performance of the battery. In contrast, the suitable hot-pressing pressure and temperature used in Example 1 help to further reduce the thickness of the membrane while maintaining the integrity of the internal structure of the composite membrane, promote the close combination between the inorganic solid electrolyte and the porous base membrane, construct a more continuous and uniform ion transmission path, ensure the uniform distribution of electrolyte particles, thereby improving the electrochemical properties and mechanical strength of the composite membrane.

[0136] It can be seen from Examples 1 and 2 that the roller-shaped vacuum filtration device and the parallel box-type vacuum filtration device used in the present invention can effectively achieve uniform compounding of the porous basement membrane and the inorganic solid electrolyte. By optimizing the suction pore area and pore coverage of the filtration surface and the adsorption pressure of the porous basement membrane containing the inorganic solid electrolyte, sufficient adsorption of the porous basement membrane containing the inorganic solid electrolyte can be achieved. In addition, by adjusting the speed difference between the roller-shaped vacuum filtration device and the parallel box-type vacuum filtration device and the porous basement membrane containing the inorganic solid electrolyte during production and use, the uniform distribution of the inorganic solid electrolyte particles in the porous basement membrane is ensured.

[0137] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a flexible composite solid electrolyte film that can be produced continuously, characterized in that: The preparation method comprises: S1: Preliminary compounding of a mixed solution A containing an inorganic solid electrolyte with a porous base membrane in operation; the porous base membrane has a porosity of 50-90% and a thickness of no more than 200 microns; S2: preparing a composite solid electrolyte film precursor by subjecting the preliminarily composited porous base membrane containing the inorganic solid electrolyte to a vacuum filtration device; S3: drying and heat-treating the composite solid electrolyte film precursor described in S2 to obtain a flexible composite solid electrolyte film; The vacuum filtration device and the porous base membrane containing an inorganic solid electrolyte are both in operation, the speed difference between the two is 0.3-2.5 m / min, the filtration pressure between the porous base membrane containing an inorganic solid electrolyte and the vacuum filtration device is 0.01-1 MPa; the pore coverage rate per unit area of ​​the vacuum filtration device is 70-95%, and the pore area range is 0.01-10 mm 2 .

2. The method for preparing a continuously producible flexible composite solid electrolyte film according to claim 1, characterized in that: The particle size of the inorganic solid electrolyte is 1-500 nanometers; the solid content of the mixed solution A is in the range of 1-50 wt %; and the pore size of the porous base membrane in S1 is selected from 1-500 nanometers.

3. The method for preparing a continuously producible flexible composite solid electrolyte film according to claim 1, characterized in that: The particle size of the inorganic solid electrolyte is selected from 50-200 nanometers.

4. The method for preparing a continuously producible flexible composite solid electrolyte film according to claim 1, characterized in that: The pore size of the porous base membrane in S1 is selected from 250-400 nanometers.

5. The method for preparing a continuously producible flexible composite solid electrolyte film according to claim 1, characterized in that: The type of the inorganic solid electrolyte is selected from one or more of an oxide solid electrolyte, a sulfide solid electrolyte, a halide solid electrolyte, a nitride solid electrolyte, a phosphate solid electrolyte, and a borate solid electrolyte; wherein the oxide solid electrolyte includes one or more of a garnet-type solid electrolyte, a perovskite-type solid electrolyte, or a NASICON-type solid electrolyte; the garnet-type solid electrolyte includes lithium lanthanum zirconium oxide or a solid electrolyte obtained by replacing, doping, or modifying lithium lanthanum zirconium oxide; the perovskite-type solid electrolyte includes lithium lanthanum titanium oxide or a solid electrolyte obtained by replacing, doping, or modifying lithium lanthanum titanium oxide; Solid electrolytes obtained by modification; NASICON solid electrolytes include lithium titanium aluminum phosphate and lithium germanium aluminum phosphate or solid electrolytes obtained by replacing, doping or modifying lithium titanium aluminum phosphate or lithium germanium aluminum phosphate; sulfide solid electrolytes include lithium germanium phosphosulfide or solid electrolytes obtained by replacing, doping or modifying lithium germanium phosphosulfide; halide solid electrolytes include Li2MnCl4 and Li2ZnCl4; nitride solid electrolytes include lithium nitride Li3N; phosphate solid electrolytes include lithium phosphate Li3PO4; borate solid electrolytes include LiBO2 and Li4B2O5; The type of the porous base membrane in S1 is selected from a polymer-based porous base membrane or a natural polymer-based porous base membrane; wherein the polymer-based porous base membrane includes one or more of polyethylene, polypropylene, polyethylene terephthalate, polyurethane, polyacrylonitrile, polyethylene oxide, polystyrene, polyvinyl chloride, polycarbonate, polymethyl methacrylate, polytetrafluoroethylene, polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, and polyimide; the natural polymer-based porous base membrane is selected from cellulose membrane and its derivatives.

6. The method for preparing a continuously producible flexible composite solid electrolyte film according to claim 1, characterized in that: The mixed solution A in S1 includes a solvent; the type of the solvent is selected from one or more of water, ethanol, isopropanol, glycerol, ethylene glycol, tetrahydrofuran, N,N-dimethylformamide, and N-methylpyrrolidine; the drying temperature in S3 is selected from 60-100 degrees, and the drying time is selected from 6-24 hours; the heat treatment method in S3 is selected from one of hot pressing or roller pressing; the pressure range is 20-50kg / cm 2 , temperature is 50-130 degrees, time is 1-15 minutes.

7. The method for preparing a continuously producible flexible composite solid electrolyte film according to claim 1, characterized in that: The vacuum filtration device in S2 is selected from a roller-shaped vacuum filtration device or a parallel box-type vacuum filtration device.

8. The method for preparing a continuously producible flexible composite solid electrolyte film according to claim 7, characterized in that: The roller-shaped vacuum filtration device comprises a vacuum filtration roller (1) for adsorbing a porous base film containing an inorganic solid electrolyte; a first rotating shaft (2) is provided inside the vacuum filtration roller (1) for driving the vacuum filtration roller to rotate; and a first air extraction hole (3) is also provided on the surface of the vacuum filtration roller (1).

9. The method for preparing a continuously producible flexible composite solid electrolyte film according to claim 8, characterized in that: The roller-shaped vacuum filtration device further comprises a flexible covering film (4); the flexible covering film (4) is adsorbed on the surface of the vacuum filtration roller (1) via a second rotating shaft (9); and is used to cover the portion of the vacuum filtration roller (1) that is not in contact with the porous base film containing the inorganic solid electrolyte.

10. The method for preparing a continuously producible flexible composite solid electrolyte film according to claim 7, characterized in that: The parallel box-type vacuum filtration device comprises a vacuum filtration box (5) for adsorbing a porous base membrane containing an inorganic solid electrolyte; a second air extraction hole (6) is provided on the surface of the vacuum filtration box (5); and a third rotating shaft (7) is provided on each side of the vacuum filtration box (5) for driving the porous base membrane containing the inorganic solid electrolyte to move.

11. The method for preparing a continuously producible flexible composite solid electrolyte film according to claim 1, characterized in that: The operating speed of the vacuum filtration device is selected from 0.1-10 m / min, and the speed difference with the porous base membrane containing the inorganic solid electrolyte is selected from 0.5-2 m / min. The pore coverage rate per unit area of ​​the vacuum filtration device is selected from 75-90%, and the range of pore area is selected from 0.1-10 mm 2 .

12. A continuously producible flexible composite solid electrolyte film obtained by the preparation method according to any one of claims 1 to 11, characterized in that: The film has a thickness of 10-40 μm and a tensile strength of 10-80 MPa.

13. A battery, characterized in that: The battery comprises the flexible composite solid electrolyte film according to claim 12.

14. An energy storage device, characterized in that: The energy storage device comprises the flexible composite solid electrolyte film according to claim 12.

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