A fibrous cloth-based battery separator and process for making the same

Abstract

The application discloses a kind of fiber cloth-based battery separators and its processing technology, belong to the technical field of separator, adopt polyacrylonitrile and polymethyl methacrylate to prepare island fiber, and to the island fiber carbonization preparation superfine carbon fiber, island fiber, superfine carbon fiber and polyolefin fiber are blended, and fiber nonwoven fabric is prepared by dry carding, and fiber cloth-based battery separator is obtained.Island fiber is with high temperature resistance high strength polyacrylonitrile as skeleton, polymethyl methacrylate has good hydrophilicity, and polyolefin fiber is blended to give separator good temperature resistance and hydrophilicity, superfine carbon fiber temperature resistance and mechanical property are good, and fiber size is small, and island fiber, polyolefin fiber is blended dry carding to prepare fiber cloth, can realize the small aperture high porosity of fiber cloth-based battery separator, and the safety of battery is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of diaphragms, and particularly relates to a fiber cloth-based battery diaphragm and a processing technology thereof. BACKGROUND

[0002] In order to promote the rapid development of the lithium ion battery industry and help the automobile industry achieve the "double carbon" goal, people have developed many new diaphragms on the basis of traditional polyolefin diaphragms based on the demand of lithium battery application scenarios.

[0003] Non-woven diaphragms are formed by orienting or randomly arranging fibers through non-woven methods to form a fiber web structure, and then using chemical or physical methods to reinforce the film to make it have good air permeability and liquid absorption rate. Polyolefin fibers are ideal substrates for preparing battery diaphragms, but polyolefin fibers have poor hydrophilic properties because there are no hydrophilic groups in the polyolefin macromolecular structure. Non-woven fabrics used for battery diaphragms must have excellent liquid absorption performance. Therefore, the hydrophilic treatment technology of polyolefin fiber non-woven fabric is a key technology for preparing battery diaphragms. In addition, polyolefin fibers have a relatively low thermal deformation temperature, and the diaphragm will undergo severe thermal shrinkage when the temperature is too high, so it is not suitable for use in high-temperature environments. Non-woven fiber cloth diaphragms have the characteristics of large pore size and high porosity. In order to reduce the pore size, the thickness must be increased, but too much thickness will affect the battery capacity. Currently, nanofiber is used to prepare fiber cloth diaphragms through electrospinning, but the relative cost of electrospinning is high, which is not conducive to the mass production of battery diaphragms.

[0004] In recent years, polyacrylonitrile has gradually become one of the diaphragm modification materials due to its excellent chemical stability and temperature resistance. Polyacrylonitrile films are mainly prepared by electrospinning, but the nanometer diaphragm material prepared by single polyacrylonitrile has defects such as poor mechanical strength and hydrophilicity, and needs to be further improved to meet the use requirements of battery diaphragms.

[0005] A battery modified polyacrylonitrile non-woven fabric / silica aerogel composite diaphragm and a preparation method thereof are disclosed in Chinese patent application No. CN201811265901.8. The modified polyacrylonitrile non-woven fabric is used as the composite diaphragm substrate, and the silica aerogel with good heat resistance and light weight is used as the coating material to improve the heat resistance of the diaphragm. However, since the silica aerogel is grown in situ on the surface of the modified polyacrylonitrile non-woven fabric, it cannot guarantee the change of the pore size and porosity of the composite diaphragm, and it does not significantly improve the mechanical properties thereof. SUMMARY

[0006] The purpose of the present application is to provide a fiber cloth-based battery diaphragm and a processing technology thereof, which effectively improve the temperature resistance and electrolyte wettability of the battery diaphragm.

[0007] The purpose of the present application can be achieved by the following technical solutions:

[0008] The application provides a fiber cloth-based battery separator, a fiber component of the separator comprising island-in-sea fibers, ultrafine carbon fibers and polyolefin fibers; the island-in-sea fibers take polyacrylonitrile as an island phase and polymethyl methacrylate as a sea phase; the ultrafine carbon fibers are carbonization products of the island-in-sea fibers; and the polyolefin fibers are any combination of polypropylene fibers and polyethylene fibers.

[0009] Further, a mass ratio of island-in-sea components of the island-in-sea fibers is (5-3):(5-7), and the more the proportion of the island component in the island-in-sea fibers, the more difficult to prepare, and the more difficult to form a continuous phase of the sea component.

[0010] Further, a proportion of the island-in-sea fibers, the ultrafine carbon fibers and the polyolefin fibers in the fiber component of the separator is: 10-30wt% of the island-in-sea fibers, 10-40wt% of the ultrafine carbon fibers, and the rest of the polyolefin fibers, and a large proportion of the island-in-sea fibers and the ultrafine fibers will increase the cost, and the ultrafine carbon fibers are beneficial to reduce the pore size of the fiber cloth and ensure good porosity.

[0011] Further, the fiber cloth-based battery separator has a pore size of 1-5μm, a porosity of 38-65%, a thickness of 20-30μm and a grammage of 10-15g / m 2 .

[0012] The application also provides a processing technology of the fiber cloth-based battery separator, and the processing technology comprises the following steps:

[0013] S1, preparing a spinning solution:

[0014] Poly methyl methacrylate and polyacrylonitrile are respectively dissolved in dimethylacetamide (DMAC) to prepare solutions, and poly methyl methacrylate spinning solution and polyacrylonitrile spinning solution are obtained respectively;

[0015] S2, preparing island-in-sea fibers and ultrafine carbon fibers:

[0016] The spinning solutions are respectively filtered and vacuum degassed for 12-24h, and then respectively enter feeding ports No.1 and No.2 of a spinning machine, and are sprayed out from an island-in-sea composite spinneret plate, and the composite fibers sprayed out from the spinneret are sequentially subjected to a coagulation bath, washing and drawing to obtain island-in-sea fibers, polyacrylonitrile as an island and polymethyl methacrylate as a sea, and 1 / 3 of the island-in-sea fibers are subjected to pre-oxidation and carbonization treatment to obtain ultrafine carbon fibers;

[0017] S3, preparing a fiber non-woven fabric:

[0018] The island-in-sea fibers, the ultrafine carbon fibers and the polyolefin fibers are blended, and are subjected to opening, carding, web laying, hot rolling and heat setting to obtain the fiber cloth-based battery separator.

[0019] Further, the concentration of the polymethyl methacrylate in the polymethyl methacrylate spinning solution is 25-30wt%, and the concentration of the polyacrylonitrile in the polyacrylonitrile spinning solution is 5%-15wt%.

[0020] Further, the flow rate ratio of the polymethyl methacrylate spinning solution to the polyacrylonitrile spinning solution is 1:1-1:5, which can be adjusted according to the required mass ratio of the island component.

[0021] Further, the component of the coagulation bath is dimethylacetamide aqueous solution, the concentration of the dimethylacetamide aqueous solution is 5%-35wt%, the temperature of the coagulation bath is 40-60℃, and the fiber coagulation time is 10-15min; the water washing time is set to 10-15min, and the water washing temperature is room temperature; the drawing multiple is 5-6 times, and the drawing temperature is 70-80℃; the drawing multiple is not too large or too small, too large will cause fiber breakage, and too small will cause the fiber to be too thick and the mechanical property to be poor.

[0022] Further, the pre-oxidation temperature of the island fiber is 200-300℃, the pre-oxidation time is 1.5-2h, the carbonization temperature is 600-1500℃, the carbonization time is 30-60min, the diameter of the island fiber is 0.8-1.2μm, and the diameter of the ultra-fine carbon fiber is 300-500nm; the carbonization treatment adopts different temperature multi-stage carbonization to realize stable and uniform carbonization of the fiber.

[0023] Further, the hot rolling reinforcement temperature is 80-105℃, and the heat setting temperature is 95-105℃.

[0024] The beneficial effects of the present application are as follows:

[0025] (1) The island fiber is prepared by combining polyacrylonitrile and polymethyl methacrylate, taking polyacrylonitrile as the island and polymethyl methacrylate as the sea; the polyacrylonitrile can improve the temperature resistance and mechanical property, and the polymethyl methacrylate can improve the electrolyte wettability of the fiber;

[0026] (2) The ultra-fine carbon fiber is obtained by removing the polymethyl methacrylate component through carbonization treatment of the island fiber, and the ultra-fine carbon fiber has excellent temperature resistance and mechanical property and can make up for the defect of large pore size of the non-woven fabric;

[0027] (3) The island fiber, the ultra-fine carbon fiber and the polyolefin fiber are blended to prepare a dry-process fiber cloth-based battery separator, which has outstanding temperature resistance, hydrophilicity and mechanical strength and can meet the requirements of small pore size and high porosity of the battery separator. DETAILED DESCRIPTION

[0028] With reference to the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0029] Example 1

[0030] Poly(methyl methacrylate) and polyacrylonitrile were dissolved in dimethylacetamide (DMAC) respectively to obtain 25wt% poly(methyl methacrylate) spinning solution and 10wt% polyacrylonitrile spinning solution.

[0031] The prepared spinning solutions were filtered and vacuum degassed for 12-24h respectively, and then entered the feeding ports No. 1 and No. 2 of the spinning machine respectively, polyacrylonitrile as islands and poly(methyl methacrylate) as seas, were sprayed out from the sea-island composite spinneret, and the flow rate ratio of poly(methyl methacrylate) spinning solution to polyacrylonitrile spinning solution was set to 1:2.5.

[0032] The composite fibers sprayed out from the spinneret entered the coagulation bath tank, the temperature of which was set to 60℃, and after coagulation for 10min, entered the washing tank, and was washed for 15min at room temperature to remove the surface solvent, and then was heat drawn, the drawing temperature was set to 80℃ and the draw ratio was set to 5 times to ensure the densification of the fiber, to obtain sea-island fibers with a diameter of 1.0μm.

[0033] 1 / 3 of the total mass of the sea-island fibers was further processed, and was pre-oxidized at 220℃ for 2h, and then was carbonized in nitrogen, and was low-temperature carbonized at 600-800℃ for 20min and high-temperature carbonized at 800-1500℃ for 10min, and in the process of carbonization, the poly(methyl methacrylate) was removed, to obtain ultra-fine carbon fibers with a diameter of 500nm.

[0034] 10wt% sea-island fibers, 10wt% ultra-fine carbon fibers and 80wt% polypropylene fibers were blended, and after opening, carding and web laying, a blended fiber web was formed, and the fiber web was heat-rolled and reinforced by a hot roller with a temperature set to 100℃, and for further improving the dimensional stability and mechanical properties of the fiber cloth, heat setting treatment was performed, and the heat setting temperature was set to 105℃, to obtain a fiber cloth-based battery separator, the thickness of the separator was 25μm and the grammage was 15g / m 2 .

[0035] Example 2

[0036] Compared with Example 1, the proportion of sea-island fibers in the fiber components was increased from 10wt% to 20wt%, and the specific implementation steps were as follows:

[0037] Poly(methyl methacrylate) and polyacrylonitrile were dissolved in dimethylacetamide (DMAC) respectively to obtain 25wt% poly(methyl methacrylate) spinning solution and 10wt% polyacrylonitrile spinning solution.

[0038] The prepared spinning solutions were filtered and vacuum degassed for 12-24h respectively, and then entered the feeding ports of spinning machines No. 1 and No. 2 respectively, polyacrylonitrile as islands and poly(methyl methacrylate) as seas, and were sprayed out by the sea-island composite spinneret, and the flow rate ratio of poly(methyl methacrylate) spinning solution to polyacrylonitrile spinning solution was set to 1:2.5.

[0039] The composite fibers sprayed out of the spinneret entered the coagulation bath tank, and the temperature of the coagulation bath tank was set to 60℃, and after coagulation for 10min, entered the washing tank at room temperature, and washed for 15min to remove the surface solvent, and then hot drawing was performed, the drawing temperature was set to 80℃, and the drawing multiple was set to 5 times to ensure the densification of the fibers, and sea-island fibers with a diameter of 1.0μm were obtained.

[0040] 1 / 3 of the total mass of the sea-island fibers was further processed, pre-oxidized at 220℃ for 2h, and then carbonized in nitrogen, low-temperature carbonized at 600-800℃ for 20min, and high-temperature carbonized at 800-1500℃ for 10min, and poly(methyl methacrylate) was removed during the carbonization process, and ultra-fine carbon fibers with a diameter of 500nm were obtained.

[0041] 20wt% sea-island fibers, 10wt% ultra-fine carbon fibers and 70wt% polypropylene fibers were blended, opened, carded and laid to form a blended fiber web, and the fiber web was hot-rolled and reinforced by a hot roller with a temperature of 100℃, and heat setting treatment was performed to further improve the dimensional stability and mechanical properties of the fiber cloth, and the heat setting temperature was set to 105℃, and a fiber cloth-based battery separator was obtained, with a thickness of 25μm and a grammage of 15g / m 2 .

[0042] Example 3

[0043] Compared with Example 1, the proportion of sea-island fibers in the fiber component was increased from 10wt% to 30wt%, and the specific implementation steps were as follows:

[0044] Poly(methyl methacrylate) and polyacrylonitrile were dissolved in dimethylacetamide (DMAC) respectively to obtain 25wt% poly(methyl methacrylate) spinning solution and 10wt% polyacrylonitrile spinning solution.

[0045] The prepared spinning solutions were filtered and vacuum degassed for 12-24h respectively, and then entered the feeding ports of spinning machines No. 1 and No. 2 respectively, polyacrylonitrile as islands and poly(methyl methacrylate) as seas, and were sprayed out by the sea-island composite spinneret, and the flow rate ratio of poly(methyl methacrylate) spinning solution to polyacrylonitrile spinning solution was set to 1:2.5.

[0046] The composite fiber coming out of the spinneret enters a coagulation bath tank, the temperature of which is set to 60°C, and after coagulation for 10 min, enters a water washing tank, and is washed for 15 min at room temperature to remove the surface solvent, and is subjected to thermal drawing, the drawing temperature being set to 80°C and the drawing multiple being set to 5 times to ensure fiber densification, to obtain sea-island fibers, the fiber diameter being 1.0 pm.

[0047] 1 / 3 of the total mass of the sea-island fibers is further processed, and is sequentially pre-oxidized at 220°C for 2 h, carbonized in nitrogen, low-temperature carbonized at 600-800°C for 20 min, and high-temperature carbonized at 800-1500°C for 10 min, to remove the polymethyl methacrylate and obtain superfine carbon fibers, the fiber diameter being 500 nm.

[0048] 30wt% sea-island fibers, 10wt% superfine carbon fibers, and 60wt% polypropylene fibers are blended, and are subjected to opening, carding, and web laying to form a blended fiber web, and the fiber web is subjected to thermal rolling and reinforcement by a hot roller set to a temperature of 100°C, and is subjected to heat setting treatment to further improve the dimensional stability and mechanical properties of the fiber cloth, the heat setting temperature being set to 105°C, to obtain a fiber cloth-based battery separator, the separator thickness being 25 pm and the grammage being 15 g / m 2 .

[0049] Example 4

[0050] In comparison with Example 1, the proportion of superfine carbon fibers in the fiber components is increased from 10wt% to 25wt%, and the specific implementation steps are as follows:

[0051] Polymethyl methacrylate and polyacrylonitrile are respectively dissolved in dimethylacetamide (DMAC) to obtain 25wt% polymethyl methacrylate spinning solution and 10wt% polyacrylonitrile spinning solution.

[0052] The prepared spinning solutions are respectively filtered and vacuum degassed for 12-24 h, and then respectively enter the feeding ports of spinning machines No. 1 and No. 2, with polyacrylonitrile as the islands and polymethyl methacrylate as the sea, and are sprayed out of a sea-island composite spinneret, and the flow rate ratio of the polymethyl methacrylate spinning solution to the polyacrylonitrile spinning solution is set to 1:2.5.

[0053] The composite fiber coming out of the spinneret enters a coagulation bath tank, the temperature of which is set to 60°C, and after coagulation for 10 min, enters a water washing tank, and is washed for 15 min at room temperature to remove the surface solvent, and is subjected to thermal drawing, the drawing temperature being set to 80°C and the drawing multiple being set to 5 times to ensure fiber densification, to obtain sea-island fibers, the fiber diameter being 1.0 pm.

[0054] Take 1 / 3 of the total mass of island fibers for further processing, sequentially pre-oxidized at 220°C for 2h, then carbonized in nitrogen, low-temperature carbonized at 600-800°C for 20min, high-temperature carbonized at 800-1500°C for 10min, and the polymethyl methacrylate is removed during the carbonization process to obtain ultra-fine carbon fibers with a fiber diameter of 500nm.

[0055] Blend 10wt% island fibers, 25wt% ultra-fine carbon fibers, and 65wt% polypropylene fibers, open, card, and lay the fiber web to form a blended fiber web, and pass the fiber web through a hot roller set at a temperature of 100°C for hot rolling and reinforcement. To further improve the dimensional stability and mechanical properties of the fiber cloth, heat setting treatment is performed at a heat setting temperature of 105°C to obtain a fiber cloth-based battery separator with a thickness of 25μm and a grammage of 15g / m 2 .

[0056] Example 5

[0057] In comparison with Example 1, the proportion of ultra-fine carbon fibers in the fiber component is increased from 10wt% to 40wt%, and the specific implementation steps are as follows:

[0058] Polymethyl methacrylate and polyacrylonitrile are dissolved in dimethylacetamide (DMAC) respectively to obtain 25wt% polymethyl methacrylate spinning solution and 10wt% polyacrylonitrile spinning solution.

[0059] The prepared spinning solutions are filtered and vacuum degassed for 12-24h respectively, then enter the feeding ports of spinning machines No. 1 and No. 2 respectively, with polyacrylonitrile as the island and polymethyl methacrylate as the sea, and are sprayed out from the island-in-sea composite spinneret, with a flow rate ratio of polymethyl methacrylate spinning solution to polyacrylonitrile spinning solution set at 1:2.5.

[0060] The composite fibers sprayed out of the spinneret enter the coagulation bath tank, with the coagulation bath tank temperature set at 60°C, and after coagulation for 10min, enter the washing tank, and are washed at room temperature for 15min to remove surface solvents, and then are heat drawn, with the drawing temperature set at 80°C and the draw ratio set at 5 times to ensure fiber densification, to obtain island fibers with a fiber diameter of 1.0μm.

[0061] Take 1 / 3 of the total mass of island fibers for further processing, sequentially pre-oxidized at 220°C for 2h, then carbonized in nitrogen, low-temperature carbonized at 600-800°C for 20min, high-temperature carbonized at 800-1500°C for 10min, and the polymethyl methacrylate is removed during the carbonization process to obtain ultra-fine carbon fibers with a fiber diameter of 500nm.

[0062] 10wt% island fiber, 40wt% ultra-fine carbon fiber and 50wt% polypropylene fiber were blended, and a blended fiber web was formed by opening, carding and laying. The fiber web was hot-rolled and reinforced by a hot roller with a temperature of 100°C. In order to further improve the dimensional stability and mechanical properties of the fiber cloth, heat setting treatment was performed, and the heat setting temperature was set to 105°C. A fiber cloth-based battery separator was obtained, with a thickness of 25μm and a grammage of 15g / m 2 .

[0063] Comparative Example 1

[0064] Compared with Example 5, the difference lies in that a single polyacrylonitrile fiber is used to prepare the fiber cloth-based battery separator.

[0065] Polypropylene fibers were formed into a blended fiber web by opening, carding and laying. The fiber web was hot-rolled and reinforced by a hot roller with a temperature of 100°C. Heat setting treatment was performed, and the heat setting temperature was set to 105°C. A fiber cloth-based battery separator was obtained, with a thickness of 25μm and a grammage of 15g / m 2 .

[0066] Comparative Example 2

[0067] Compared with Example 5, the difference lies in that polyacrylonitrile fiber is used to replace the island fiber and ultra-fine carbon fiber in the preparation of the fiber cloth-based battery separator, and the polyacrylonitrile fiber is prepared by the same wet spinning method as in Example 5.

[0068] 50wt% polyacrylonitrile fiber and 50wt% polypropylene fiber were blended, and the polyacrylonitrile fiber had a diameter of 1μm. A blended fiber web was formed by opening, carding and laying. The fiber web was hot-rolled and reinforced by a hot roller with a temperature of 100°C. In order to further improve the dimensional stability and mechanical properties of the fiber cloth, heat setting treatment was performed, and the heat setting temperature was set to 105°C. A fiber cloth-based battery separator was obtained, with a thickness of 25μm and a grammage of 15g / m 2 .

[0069] Comparative Example 3

[0070] Compared with Example 5, the difference lies in that carbon nanofiber is used to replace the island fiber and ultra-fine carbon fiber in the preparation of the fiber cloth-based battery separator, and the carbon nanofiber is prepared by electrospinning, with a fiber diameter of 500nm.

[0071] 50wt% electrospun carbon nanofiber and 50wt% polypropylene fiber were blended, and a blended fiber web was formed by opening, carding and laying. The fiber web was hot-rolled and reinforced by a hot roller with a temperature of 100°C. In order to further improve the dimensional stability and mechanical properties of the fiber cloth, heat setting treatment was performed, and the heat setting temperature was set to 105°C. A fiber cloth-based battery separator was obtained, with a thickness of 25μm and a grammage of 15g / m2 .

[0072] The performance tests of Example 1-Example 5 and Comparative Example 1-Comparative Example 3 were carried out according to GB / T36363-2018 "Lithium ion battery separator performance test", and the results are shown in Table 1.

[0073] The thermal shrinkage test method is to measure the area change of the separator before and after heat treatment by placing the sample in a 150°C oven for 60 minutes.

[0074] Table 1

[0075]

[0076] As can be seen from Table 1, the proportion of island fibers in Example 1-3 gradually increases, and the performance of the separator is improved. Polymethyl methacrylate can improve hydrophilicity, and polyacrylonitrile can enhance tensile strength and thermal stability. Among them, the electrolyte contact angle of Example 3 is only 9.1°, and the electrolyte wettability is greatly improved. The content of superfine carbon fiber in Example 4 and Example 5 gradually increases compared with Example 1, and the thermal stability of the separator is significantly improved. The thermal shrinkage rate at 150°C is reduced to 0%, which can avoid the risk of battery short circuit at high temperature, and the tensile strength of the separator is increased to 104MPa, which can ensure the safety of the battery. In addition, the increase of superfine carbon fiber on the one hand increases the porosity of the separator, and on the other hand makes the pore size of the separator smaller, which is beneficial to the migration of ions in the battery. Comparative Example 1 is a fiber cloth-based separator prepared by a single polypropylene fiber component, and its performance is poor. Comparative Example 2 is a temperature-resistant modification by adding conventional polyacrylonitrile fiber to polypropylene fiber, and its temperature resistance and tensile strength are greatly improved compared with Comparative Example 1, but its hydrophilicity is significantly worse than Example 5. Comparative Example 3 uses electrospun carbon nanofiber and polypropylene fiber to prepare a separator. Due to the effect of nanometer carbon fiber, the thermal shrinkage rate is low and the pore size is small, but the mechanical properties of electrospun fiber are relatively poor, and carbon fiber is a hydrophobic fiber with poor affinity with electrolyte, and the contact angle is large. Comprehensive analysis shows that the fiber cloth-based separator prepared in Example 5 has good mechanical properties, thermal stability and electrolyte wettability, high porosity and small pore size, and obvious advantages.

[0077] It should be noted that, in this text, relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0078] While embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fibrous cloth-based battery separator, characterized by, The diaphragm comprises island fibers, ultra-fine carbon fibers and polyolefin fibers; The island fibers take polyacrylonitrile as island phase and polymethyl methacrylate as sea phase; The ultra-fine carbon fibers are carbonization products of the island fibers; The polyolefin fibers are any combination of polypropylene fibers and polyethylene fibers; The fiber cloth-based battery diaphragm is prepared by the following steps: S1, preparing spinning solution: Polyacrylonitrile and polymethyl methacrylate are respectively dissolved in dimethylacetamide to prepare solutions, and polyacrylonitrile spinning solution and polymethyl methacrylate spinning solution are obtained respectively; S2, preparing island fibers and ultra-fine carbon fibers: The spinning solutions are respectively filtered and vacuum degassed for 12-24 hours, and then respectively enter the feeding ports of spinning machines No. 1 and No. 2, are sprayed out by island type composite spinneret, and the composite fibers sprayed out of the spinneret successively pass through coagulation bath, washing, drawing to obtain island fibers, polyacrylonitrile as island and polymethyl methacrylate as sea; 1 / 3 of the island fibers by mass fraction are treated by pre-oxidation and carbonization to obtain ultra-fine carbon fibers; S3, preparing fiber non-woven fabric: The island fibers, ultra-fine carbon fibers and polyolefin fibers are blended, and fiber cloth-based battery diaphragm is obtained by opening, carding, laying, hot rolling and heat setting.

2. A fibrous cloth-based battery separator according to claim 1, characterized in that, The mass ratio of island components of the island fibers is (5-3):(5-7).

3. A fibrous cloth-based battery separator according to claim 1, characterized in that, According to weight percentage, the island fibers are 10wt%-30wt%, the ultra-fine carbon fibers are 10wt%-40wt%, and the rest is polyolefin fibers.

4. The fibrous cloth-based battery separator of claim 1, wherein, The fiber cloth-based battery separator has a pore size of 1-3 μm, a porosity of 38-65%, a thickness of 20-30 μm, and a grammage of 10-15 g / m 2 .

5. A process for the production of a fibrous cloth-based battery separator as claimed in any one of claims 1 to 4, characterized in that, The steps include the following: S1, preparing spinning solution: Polyacrylonitrile and polymethyl methacrylate are respectively dissolved in dimethylacetamide to prepare solutions, and polyacrylonitrile spinning solution and polymethyl methacrylate spinning solution are obtained respectively; S2, preparing island fibers and ultra-fine carbon fibers: The spinning solutions are respectively filtered and vacuum degassed for 12-24 hours, and then respectively enter the feeding ports of spinning machines No. 1 and No. 2, are sprayed out by island type composite spinneret, and the composite fibers sprayed out of the spinneret successively pass through coagulation bath, washing, drawing to obtain island fibers, polyacrylonitrile as island and polymethyl methacrylate as sea; 1 / 3 of the island fibers by mass fraction are treated by pre-oxidation and carbonization to obtain ultra-fine carbon fibers; S3, preparing fiber non-woven fabric: The island fibers, ultra-fine carbon fibers and polyolefin fibers are blended, and fiber cloth-based battery diaphragm is obtained by opening, carding, laying, hot rolling and heat setting.

6. The process for processing a fibrous cloth-based battery separator membrane according to claim 5, wherein The concentration of polymethyl methacrylate in the polymethyl methacrylate spinning solution is 25wt%-30wt%, and the concentration of polyacrylonitrile in the polyacrylonitrile spinning solution is 5wt%-15wt%.

7. The process for processing a fibrous cloth-based battery separator membrane according to claim 5, wherein The flow rate ratio of the polymethyl methacrylate spinning solution to the polyacrylonitrile spinning solution is 1:1-1:

5.

8. The process for processing a fibrous cloth-based battery separator membrane according to claim 5, wherein, The components of the coagulation bath are dimethylacetamide aqueous solution, the concentration of the dimethylacetamide aqueous solution is 5wt%-35wt%, the temperature of the coagulation bath is set to 40-60℃, and the fiber coagulation time is 10-15min; the washing time is 10-15min, and the washing temperature is room temperature; the drawing multiple is 5-6 times, and the drawing temperature is set to 70-80℃.

9. The process for processing a fibrous cloth-based battery separator membrane according to claim 5, wherein, The pre-oxidation temperature of the island fiber is 200-300 DEG C, the pre-oxidation time is 1.5-2h, the carbonization temperature is 600-1500 DEG C, the carbonization time is 30-60min, the island fiber diameter is 0.8-1.2mu m, and the ultra-fine carbon fiber diameter is 300-500nm.

10. The process for processing a fibrous cloth-based battery separator membrane as claimed in claim 5, wherein, The hot rolling reinforcement temperature is 80-105 DEG C, and the hot setting temperature is 95-105 DEG C.

Images