CN114429864A - Composite electrolytic paper for capacitor and preparation method thereof - Google Patents
Composite electrolytic paper for capacitor and preparation method thereof Download PDFInfo
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- 239000002131 composite material Substances 0.000 title claims abstract description 86
- 239000003990 capacitor Substances 0.000 title claims abstract description 68
- 238000002360 preparation method Methods 0.000 title abstract description 9
- 239000002121 nanofiber Substances 0.000 claims abstract description 63
- 239000012528 membrane Substances 0.000 claims abstract description 55
- 229920000642 polymer Polymers 0.000 claims abstract description 12
- 238000009987 spinning Methods 0.000 claims description 40
- 238000010041 electrostatic spinning Methods 0.000 claims description 16
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 9
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims description 9
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 9
- 239000002904 solvent Substances 0.000 claims description 7
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 6
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 6
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 6
- 229920002239 polyacrylonitrile Polymers 0.000 claims description 6
- 238000003756 stirring Methods 0.000 claims description 5
- 238000004804 winding Methods 0.000 claims description 5
- 239000004952 Polyamide Substances 0.000 claims description 4
- 239000004642 Polyimide Substances 0.000 claims description 4
- 239000005038 ethylene vinyl acetate Substances 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 229920002647 polyamide Polymers 0.000 claims description 4
- -1 polyethylene, ethylene-vinyl acetate Polymers 0.000 claims description 4
- 229920001721 polyimide Polymers 0.000 claims description 4
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 claims description 3
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 claims description 3
- 238000001523 electrospinning Methods 0.000 claims description 3
- 235000019253 formic acid Nutrition 0.000 claims description 3
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims description 3
- 230000003746 surface roughness Effects 0.000 claims description 2
- 239000000123 paper Substances 0.000 description 155
- 239000003792 electrolyte Substances 0.000 description 19
- 239000000835 fiber Substances 0.000 description 19
- 238000012360 testing method Methods 0.000 description 13
- 230000015556 catabolic process Effects 0.000 description 12
- 241000196324 Embryophyta Species 0.000 description 8
- 239000011888 foil Substances 0.000 description 7
- 239000012535 impurity Substances 0.000 description 5
- 238000001179 sorption measurement Methods 0.000 description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- 238000013461 design Methods 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 244000146553 Ceiba pentandra Species 0.000 description 2
- 235000003301 Ceiba pentandra Nutrition 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 240000000907 Musa textilis Species 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000002657 fibrous material Substances 0.000 description 2
- 229920006158 high molecular weight polymer Polymers 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 239000002655 kraft paper Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000002023 wood Substances 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000007605 air drying Methods 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 238000010835 comparative analysis Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000010294 electrolyte impregnation Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
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- 238000011056 performance test Methods 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
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- 230000007847 structural defect Effects 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/022—Electrolytes; Absorbents
- H01G9/025—Solid electrolytes
- H01G9/028—Organic semiconducting electrolytes, e.g. TCNQ
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- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Nonwoven Fabrics (AREA)
Abstract
The invention provides composite electrolytic paper for a capacitor and a preparation method thereof. The composite electrolytic paper comprises: an electrolytic paper base film; and a porous nanofiber membrane layer deposited on at least one surface of the electrolytic paper-based membrane; wherein the porous nanofiber membrane is made of a high molecular polymer resistant to the temperature of more than 200 ℃. The invention also provides a preparation method of the composite electrolytic paper. The capacitor containing the composite electrolytic paper has the advantages of small volume, high specific capacity, small internal resistance, strong pressure resistance, good safety performance and the like.
Description
Technical Field
The invention relates to the technical field of capacitors, in particular to composite electrolytic paper for a capacitor and a preparation method thereof.
Background
The capacitor is an essential electronic component of all electronic circuits, and the downstream market of the capacitor is very wide. In the last decade, the capacitor market in China has steadily expanded, with the market growth far above the global average level. The electrolytic paper is one of three major structures of the capacitor, and the market expansion of the capacitor inevitably drives the market demand of the electrolytic paper.
As is well known, electrolytic paper is interposed between a cathode foil and an anode foil in a capacitor to prevent short-circuiting therebetween, and its porous structure adsorbs a large amount of electrolyte, and is an indispensable part of the capacitor as a cathode carrier. At present, the electrolytic paper is mostly made of wood, kraft paper, kapok or manila hemp and other plant fiber materials, and the liquid absorption performance is general and the ESR is large due to small porosity; another fatal problem of the electrolytic paper is that the pressure resistance and burr puncture resistance are poor, and the puncture short circuit failure is easy to cause. Therefore, the development of high-strength electrolytic paper with strong liquid absorption capacity, low ESR loss and high pressure resistance has important research value for market expansion of novel electrolytic paper and development of future high-performance capacitors.
CN111048315A discloses a method for manufacturing a laminated aluminum electrolytic capacitor and a capacitor manufactured by the method, in the technical scheme, electrolytic paper is directly prepared on the surface of an anode foil through electrostatic spinning, but the size of the electrolytic paper depends on the size of the anode foil and cannot be larger than the anode foil, and the defect of easy short circuit exists.
Disclosure of Invention
The invention aims to solve at least one of the following technical problems to a certain extent:
(1) the traditional electrolytic paper mainly adopts plant fiber materials such as wood, manila hemp, kraft paper, kapok and the like, and the microstructure of the electrolytic paper is observed by using a field emission scanning electron microscope. It can be found that in the size range of tens of microns, almost no obvious holes exist, so that the traditional electrolytic paper has higher density, low porosity, general electrolyte adsorption capacity and limited ionic charge transmission;
(2) the traditional electrolytic paper is made of plant fibers, the fiber diameter is distributed between dozens of micrometers and hundreds of micrometers, and the disordered distribution of the large-diameter fibers causes the electrolytic paper to have the phenomenon of different thicknesses, so that the electrolytic paper has poor high-pressure resistance or burr breakdown resistance, and is easy to cause the phenomena of breakdown, short circuit, failure and the like;
(3) the traditional electrolytic paper is derived from plant fiber, and the main component of the traditional electrolytic paper comprises alpha-cellulosePentosan and lignin, and also contains a small amount of impurities, and the aluminum electrolytic capacitor requires the electrolytic paper to contain very little impurities, such as chloride ion concentration lower than 1mg/L and iron particle concentration lower than 5/1800 cm2The existence of the impurities can corrode the aluminum foil, so that the capacitor fails and other serious consequences are caused;
(4) the fibers in the electrolytic paper are flat, and when the electrolytic paper is soaked in the electrolyte, the current path is long, the resistance is increased, and the defects of resistance increase, loss increase and the like of the capacitor are further caused.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a composite electrolytic paper for capacitors, comprising:
an electrolytic paper base film;
and a porous nanofiber membrane layer deposited on at least one surface of the electrolytic paper-based membrane;
wherein the porous nanofiber membrane is made of a high molecular polymer resistant to the temperature of more than 200 ℃.
According to the invention, the porous nanofiber membrane layer of the high molecular polymer is deposited on the surface of the traditional electrolytic paper, on one hand, the specific surface area of the electrolytic paper is greatly increased due to the porous structure, so that the electrolyte impregnation capacity of the composite electrolytic paper is obviously improved, the transmission of ions and charges is facilitated, the internal resistance is reduced, and the conductivity is improved; secondly, through process control, the thickness uniformity of the porous nanofiber membrane layer can be ensured, and the high-voltage resistance and burr breakdown resistance of the electrolytic paper are improved; moreover, the high molecular polymer has less impurities, and the adverse effect of the traditional electrolytic paper on the performance of the capacitor due to impurity pollution can be reduced.
Specifically, the base membrane of the electrolytic paper is traditional electrolytic paper made of plant fibers, the material is plant fibers, and the roughness of the surface of the plant fibers in the electrolytic paper is generally 10-500nm, so that the porous nano fibers with the average diameter close to the roughness range can be firmly attached to the surface of the electrolytic paper and are not easy to fall off.
The base film of the electrolytic paper can be high-density or low-density electrolytic paper, and the thickness is not too thick, and preferably, the thickness of the base film of the electrolytic paper is 20-50 μm.
In the composite electrolytic paper provided by the invention, the specific surface area of the porous nanofiber membrane is larger, so that the specific surface area of the obtained composite electrolytic paper is also larger and is about 1-1000m2Is much higher than the traditional electrolytic paper (less than 0.1 m)2/g)。
In the composite electrolytic paper provided by the invention, the density of the composite electrolytic paper is 0.2-0.75g/cm3Is lower than that of the traditional electrolytic paper (0.85 g/cm)3)。
According to the embodiment provided by the invention, the high molecular polymer is at least one of polyacrylonitrile, polyethylene, ethylene-vinyl acetate copolymer, polyimide and polyamide. But is not limited thereto.
The thickness of the porous nanofiber membrane layer is controlled to be 1-1000 mu m, and when the composite electrolytic paper obtained in the thickness range is applied to a capacitor, the composite electrolytic paper can be small in size and high in capacitance, and can ensure the high-voltage resistance and other safety and stability performances of the capacitor. If the thickness of the porous nanofiber membrane layer is further increased, the high voltage resistance can be improved, but the internal loss is increased, the volume of the capacitor is increased, and the capacitance is reduced; if the thickness is too thin, the advantages of the porous nanofiber membrane layer cannot be shown, so that the high pressure difference resistance, the breakdown easiness and the like are caused.
According to some embodiments of the invention, the porous nanofiber membrane layer has a thickness of 5 to 100 μm.
According to still further embodiments provided herein, the porous nanofiber membrane layer has a thickness of 5 to 30 μm.
The average diameter of the nano-fibers in the porous nano-fiber membrane layer is controlled to be 50-600 nm. The interface bonding force of the porous nanofiber membrane layer and the electrolytic paper is closely related to the diameter of the nanofiber, when the average diameter of the nanofiber is smaller than 600nm, the interface bonding of the fiber membrane and the traditional electrolytic paper base membrane is good, when the average diameter of the nanofiber is far larger than the roughness (10-500nm) of the traditional electrolytic paper base membrane, the contact effective area of the nanofiber and the traditional electrolytic paper base membrane is reduced, and the interface bonding force is reduced.
The shape of the nanofiber in the porous nanofiber membrane layer is preferably cylindrical, and the nanofiber in the shape can enable a current path to be obviously shortened compared with the traditional electrolytic paper, so that equivalent series resistance is greatly reduced, and the loss value of the capacitor is reduced.
In a second aspect, the present invention provides a method for preparing the above composite electrolytic paper, comprising the steps of:
(1) preparing a spinning solution: stirring and dissolving a high molecular polymer in a solvent to obtain a spinning solution;
(2) electrostatic spinning: and (3) carrying out electrostatic spinning on the prepared spinning solution by taking electrolytic paper as a base film to obtain the composite electrolytic paper.
The mass fraction of the spinning solution is 5-50%, preferably 5-40%. If the concentration of the spinning solution is too high, the average diameter of fibers obtained by spinning is far larger than the roughness (10-500nm) of a traditional electrolytic paper base film, so that the contact effective area of the interface of the nanofiber membrane layer and the traditional electrolytic paper is greatly reduced, the interface bonding force is reduced, and the nanofiber membrane layer is easy to fall off from the surface of the traditional electrolytic paper.
The high molecular polymer is at least one of polyacrylonitrile, polyethylene, ethylene-vinyl acetate copolymer, polyimide and polyamide.
The solvent is at least one of ethyl acetate, formic acid, acetic acid, N-dimethylformamide, N-dimethylacetamide, toluene and tetrahydrofuran.
The parameters of the electrostatic spinning comprise: the positive high voltage is 20-100kV, the negative high voltage is-20- (-100) kV, the spinning distance is 15-40cm, the feeding speed of the spinning solution is 0.5-5L/h, and the winding speed is 0.1-10 m/min.
Specifically, single-sided or double-sided spinning, that is, spinning on one or both sides of the electrolytic paper, may be performed, and single-sided spinning is preferred.
In a third aspect, the present invention provides a capacitor comprising the above-described composite electrolytic paper. The capacitor has the advantages of small volume, high specific capacity, small internal resistance, strong pressure resistance, good safety performance and the like.
Compared with the prior art, the invention has the following technical effects:
(1) according to the composite electrolytic paper provided by the invention, the average diameter of the nano-fibers is controlled within 600nm, the porous nano-fiber film layer and the electrolytic paper base film have strong interface binding force, and the composite electrolytic paper does not fall off or peel off after being soaked in the electrolyte at high temperature.
(2) According to the composite electrolytic paper provided by the invention, the existence of the porous nanofiber membrane enables the electrolytic paper to have higher specific surface area and high-voltage (burr) resistant breakdown performance. The improvement of the specific surface area enables the nanofiber composite electrolytic paper to have stronger electrolyte adsorption capacity, and the improvement of high-voltage resistance (burr resistance) breakdown capacity enables the nanofiber composite electrolytic paper to have wider application prospects in high-voltage large-capacity capacitors.
(3) According to the composite electrolytic paper provided by the invention, the nanofibers in the nanofiber membrane layer are cylindrical, so that the current path is effectively shortened, and when the capacitor is assembled, the equivalent series resistance of the capacitor is reduced, so that the internal loss is reduced.
(4) The composite electrolytic paper provided by the invention has comprehensive performance superior to that of the traditional electrolytic paper with the same thickness. Under the condition that various performance indexes meet the requirement of the capacitor, the thicker traditional electrolytic paper is replaced by the composite electrolytic paper with the thinner thickness, so that the capacity of the capacitor is improved or the volume of the core cladding is reduced. Under the design of the same core package volume, the capacitance of a capacitor product made of the composite electrolytic paper with the thinner thickness is improved to 11 percent; under the same capacitor capacity design, the volume of the roll core bag adopting the composite electrolytic paper with thinner thickness is reduced to 7.8%, which is beneficial to the design of miniaturized products or the improvement of the buffer space of the capacitor.
Drawings
FIG. 1 is a schematic structural diagram of a composite electrolytic paper provided by an embodiment of the present invention;
wherein: 1, composite electrolytic paper, 2, an electrolytic paper base film and 3, a porous nanofiber membrane layer;
the porous nanofiber membrane layer 3 is spun on the base electrolytic paper film 2 on one side.
Detailed Description
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All patents and publications referred to herein are incorporated by reference in their entirety. The term "comprising" or "comprises" is open-ended, i.e. comprising what is specified in the present invention, but not excluding other aspects.
According to the specific embodiment provided by the invention, the preparation method of the composite electrolytic paper is explained in detail.
1. Preparation of the spinning dope
Dissolving the high molecular polymer in a solvent at 25-100 ℃ by stirring to obtain a spinning solution with the mass fraction of 5-50%.
In some embodiments, the mass fraction of the spinning dope is 5 to 40%, for example: 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, etc. Within the range, the porous nanofiber membrane with ideal performance indexes can be obtained by matching with proper electrostatic spinning parameters.
The high molecular polymer is at least one of polyacrylonitrile, polyethylene, ethylene-vinyl acetate copolymer, polyimide and polyamide.
In some embodiments, the high molecular weight polymer is polyacrylonitrile.
The solvent is at least one of ethyl acetate, formic acid, acetic acid, N-dimethylformamide, N-dimethylacetamide, toluene and tetrahydrofuran.
In some embodiments, the high molecular weight polymer is dissolved in the solvent at 60-80 ℃ with stirring to obtain a spinning solution with a mass fraction of 5-40%.
2. Electrostatic spinning
And transferring the spinning solution into electrostatic spinning equipment, and carrying out single-side spinning by taking electrolytic paper as a base film to obtain the composite electrolytic paper.
Specifically, the base film of the electrolytic paper is traditional electrolytic paper made of plant fibers, and the surface roughness of the base film is 10-500 nm.
The thickness of the base film of the electrolytic paper is 20 to 50 μm, for example: 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, and the like.
The environment condition of electrostatic spinning is preferably 20-50 deg.C and 10-40% humidity.
According to an embodiment of the present invention, the parameter setting of the electrospinning includes:
the positive high voltage is 20-100kV, for example: 20kV, 25kV, 30kV, 35kV, 40kV, 45kV, 50kV, 55kV, 60kV, 65kV, 70kV, 75kV, 80kV, 85kV, 90kV, 95kV, 100kV, etc.;
the negative high voltage is-20- (-100) kV, for example: -20kV, -25kV, -30kV, -35kV, -40kV, -45kV, -50kV, -55kV, -60kV, -65kV, -70kV, -75kV, -80kV, -85kV, -90kV, -95kV, -100kV, etc.;
spinning distances of 15-40cm, for example: 15cm, 20cm, 25cm, 30cm, 35cm, 40cm, and so forth;
the spinning solution feed rate is 0.5 to 5L/h, for example: 0.5L/h, 1L/h, 1.5L/h, 2L/h, 2.5L/h, 3L/h, 3.5L/h, 4L/h, 4.5L/h, 5L/h, etc.;
the take-up rate is 0.1 to 10m/min, for example: 0.1m/min, 0.25m/min, 0.5m/min, 0.75m/min, 1m/min, 1.5m/min, 2m/min, 2.5m/min, 3m/min, 3.5m/min, 4m/min, 4.5m/min, 5m/min, 5.5m/min, 6m/min, 6.5m/min, 7m/min, 7.5m/min, 8m/min, 8.5m/min, 9m/min, 9.5m/min, 10m/min, and the like.
In some embodiments, the take-up rate is 0.2 to 5 m/min; in some embodiments, the take-up rate is 0.2 to 3 m/min.
When electrostatic spinning is carried out, the average diameter of the obtained nano-fiber is controlled to be 50-600nm, for example: 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, 210nm, 220nm, 230nm, 240nm, 250nm, 260nm, 270nm, 280nm, 290nm, 300nm, 310nm, 320nm, 330nm, 340nm, 350nm, 360nm, 370nm, 380nm, 390nm, 400nm, 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm, 490nm, 500nm, 510nm, 520nm, 530nm, 540nm, 550nm, 560nm, 570nm, 580nm, 590nm, 600nm, and the like.
The thickness of the porous nanofiber membrane layer obtained by electrospinning is controlled to be 1 to 1000 μm, preferably 5 to 100 μm, more preferably 5 to 30 μm, for example: 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, 28 μm, 30 μm, and the like.
The specific surface area of the composite electrolytic paper is 1-1000m2(ii) in terms of/g. In some embodiments, the specific surface area of the composite electrolytic paper is 10 to 100m2(ii) in terms of/g. In other embodiments, the specific surface area of the composite electrolytic paper is 20 to 60m2/g。
The density of the composite electrolytic paper is 0.2-0.75g/cm3. In some embodiments, the composite electrolytic paper has a density of 0.4 to 0.75g/cm3。
Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
Example 1
Weighing 5kg of polyacrylonitrile in 45kg of N, N-dimethylformamide, and fully stirring and dissolving at 70 ℃ to obtain a clear spinning solution with the mass fraction of 10%;
transferring the spinning solution to electrostatic spinning equipment, placing N-20 type traditional electrolytic paper with the thickness of 20 mu m on a collecting conveyor belt, and setting electrostatic spinning parameters: the positive high voltage is 50kV, the negative high voltage is-50 kV, the spinning distance is 20cm, the spinning solution supply rate is 1L/h, the winding rate is 0.75m/min, the traditional electrolytic paper is used as a base film, single-side electrostatic spinning is carried out, the average diameter of spinning fibers is controlled to be 200nm, and the composite electrolytic paper with the porous nanofiber membrane layer deposited is obtained, wherein the thickness of the porous nanofiber membrane layer is 10 microns. And finally, placing the composite electrolytic paper in a forced air drying oven for drying treatment at 50 ℃ and storing.
Example 2
In the present embodiment, the difference from embodiment 1 is: and increasing the winding speed to 1.5m/min, and controlling the average diameter of the spinning fibers to be 200nm to obtain the composite electrolytic paper with the porous nanofiber membrane layer deposited, wherein the thickness of the porous nanofiber membrane layer is 5 microns.
Example 3
In the present embodiment, the difference from embodiment 1 is: and reducing the rolling speed to 0.25m/min, and controlling the average diameter of the spinning fibers to be 200nm to obtain the composite electrolytic paper with the porous nanofiber membrane layer deposited, wherein the thickness of the porous nanofiber membrane layer is 30 microns.
Example 4
In the present embodiment, the difference from embodiment 1 is: adjusting the mass fraction of the spinning solution to 5%, and controlling the average diameter of the spinning fibers to be 50nm to obtain the composite electrolytic paper with the porous nanofiber membrane layer deposited, wherein the thickness of the porous nanofiber membrane layer is 10 microns.
Example 5
In the present embodiment, the difference from embodiment 1 is: adjusting the mass fraction of the spinning solution to 25%, and controlling the average diameter of the spinning fibers to be 400nm to obtain the composite electrolytic paper with the porous nanofiber membrane layer deposited, wherein the thickness of the porous nanofiber membrane layer is 10 microns.
Example 6
In the present embodiment, the difference from embodiment 1 is: adjusting the mass fraction of the spinning solution to 40%, and controlling the average diameter of the spinning fibers to be 600nm to obtain the composite electrolytic paper with the porous nanofiber membrane layer deposited, wherein the thickness of the porous nanofiber membrane layer is 10 microns.
Example 7
In the present embodiment, the difference from embodiment 1 is: replacing the N-20 type traditional electrolytic paper with the thickness of 20 mu m with the H-20 type traditional electrolytic paper with the thickness of 20 mu m, and controlling the average diameter of the spinning fibers to be 200nm to obtain the composite electrolytic paper with the deposited porous nanofiber membrane layer, wherein the thickness of the porous nanofiber membrane layer is 10 mu m.
Example 8
In the present embodiment, the difference from embodiment 1 is: replacing the N-20 type traditional electrolytic paper with the thickness of 20 mu m with T-20 type traditional electrolytic paper with the thickness of 20 mu m, and controlling the average diameter of the spinning fibers to be 200nm to obtain the composite electrolytic paper with the deposited porous nanofiber membrane layer, wherein the thickness of the porous nanofiber membrane layer is 10 mu m.
Performance testing
1. Interface combination condition test of porous nanofiber membrane layer and electrolytic paper base membrane
The composite electrolytic paper prepared in the examples 1 to 8 is placed in an electrolyte at 125 ℃ and is kept warm for 96 hours, then the composite electrolytic paper is taken out and dried, the composite electrolytic paper keeps a complete structure, and structural defects such as obvious fracture, shedding or peeling do not occur, so that the interface bonding condition of the porous nanofiber membrane layer and the electrolytic paper base membrane is good.
2. Electrolyte adsorption Capacity test
The composite electrolytic paper prepared in the examples 1 to 6 and the N-30 type traditional electrolytic paper with the thickness of 30 mu m are soaked in the electrolyte, and after 10min, the rise height of the electrolyte of the composite electrolytic paper is 12-14mm, while the rise height of the electrolyte of the N-30 type traditional electrolytic paper is only 2 mm; the composite electrolytic paper prepared in the example 7 and the H-30 type traditional electrolytic paper with the thickness of 30 mu m are soaked in the electrolyte, and after 10min, the rise height of the electrolyte of the composite electrolytic paper is 13mm, while the rise height of the electrolyte of the H-30 type traditional electrolytic paper is only 2 mm; the composite electrolytic paper prepared in example 8 and a T-30 type conventional electrolytic paper having a thickness of 30 μm were impregnated with the electrolyte, and the electrolyte rise height of the composite electrolytic paper was 14mm over 10min, whereas the electrolyte rise height of the T-30 type conventional electrolytic paper was only 2 mm. Therefore, the composite electrolytic paper has stronger electrolyte adsorption capacity.
3. The composite electrolytic papers prepared in examples 1 to 8 and the dried N-30/H-30/T-30 type conventional electrolytic papers were subjected to density, specific surface area and breakdown voltage tests, and the results are shown in Table 1.
TABLE 1
| Electrolytic paper type | Density (g/cm)3) | Specific surface area (m)2/g) | Breakdown voltage (V) |
| Example 1 | 0.68 | 43.1 | >1000 |
| Example 2 | 0.71 | 27.5 | >1000 |
| Example 3 | 0.49 | 86.3 | >1000 |
| Example 4 | 0.70 | 56.4 | >1000 |
| Example 5 | 0.65 | 39.7 | >1000 |
| Example 6 | 0.63 | 35.4 | >1000 |
| Example 7 | 0.69 | 45.3 | >1000 |
| Example 8 | 0.68 | 44.0 | >1000 |
| Model number N-30 | 0.85 | 0.083 | 565 |
| H-30 type | 0.85 | 0.081 | 647 |
| Model T-30 | 0.85 | 0.084 | 578 |
The comparative test results show that the composite electrolytic paper obtained by the embodiment of the invention has lower density, larger specific surface area and higher breakdown voltage compared with the traditional electrolytic paper. The composite electrolytic paper with low density and high specific surface area is favorable for improving the electrolyte adsorption capacity and the ion transmission capacity of the core in the application of the capacitor, reducing the internal resistance and the internal loss and prolonging the service life of the capacitor product. The voltage breakdown test results show that the breakdown voltage of the composite electrolytic paper prepared in examples 1-8 is higher than the upper limit value (1000V) of the withstand voltage test, and is superior to three types of traditional electrolytic paper, so that the composite electrolytic paper has higher withstand voltage performance, and provides guarantee for the safety and stability of the capacitor in practical application.
4. Loss testing of capacitors
The composite electrolytic paper prepared in example 1 and a conventional N-30 type electrolytic paper with a thickness of 30 μm were assembled into capacitors, respectively, and the product specification was 500V100 μ F, and the product size was 18 x 45 mm. The preparation process comprises the following steps: firstly, cutting two kinds of electrolytic paper, aluminum foil and lead strips into coils; then, two kinds of electrolytic paper are respectively used for winding into a core by riveting, the core is soaked by the prepared electrolyte, the core is printed and assembled by an aluminum shell and a sleeve, and finally, the composite electrolytic paper capacitor and the traditional electrolytic paper capacitor can be obtained by aging and the performance comparison test is carried out on the composite electrolytic paper capacitor and the traditional electrolytic paper capacitor.
Through comparative analysis, the loss value of the capacitor product manufactured by the electrostatic spinning nanofiber composite electrolytic paper is 5.2%, the loss value of the capacitor product manufactured by the traditional electrolytic paper is 5.6%, and compared with the loss value of the capacitor product manufactured by the traditional electrolytic paper, the loss value of the capacitor product manufactured by the electrostatic spinning nanofiber composite electrolytic paper is 7% lower than that of the capacitor product manufactured by the traditional electrolytic paper, the heat generation of the product can be effectively reduced, and the long service life of the product is realized.
5. Superiority test of composite electrolytic paper with reduced thickness
Capacitor products were assembled from 25 μm composite electrolytic paper prepared in example 2 and 30 μm N-30 type conventional electrolytic paper, respectively, with a product specification of 500V100 μ F and a product size of 18 x 45 mm. The preparation process is the same as that described in the above 4.
Through test analysis, under the same capacitor capacity, the capacitor product is prepared by replacing the N-30 type traditional electrolytic paper with the composite electrolytic paper with the thickness of 25 microns, the volume of the rolled core bag is reduced to 7.8%, and the miniaturization design of the product or the improvement of the buffer space of the capacitor are facilitated; under the same core package volume, a capacitor is prepared by replacing 30 mu m of N-30 type traditional electrolytic paper with 25 mu m of composite electrolytic paper, the capacitance of the 30 mu m of N-30 type traditional electrolytic paper assembled capacitor is 82.3 mu F, and the capacitance of the 25 mu m of composite electrolytic paper assembled capacitor is 91.3 mu F, and the capacitance is increased to 11 percent by comparison.
10 capacitor products are respectively subjected to safety performance test, and the test standard is as follows: the pressure was increased at 1.5 times the rated operating voltage (500V by 1.5V to 750V) and under the condition of current 1A until the product opened, and the product was observed to see whether the product broke down or ignited during the whole process.
Through tests, the prepared 25-micron composite electrolytic paper and the 30-micron N-30 type traditional electrolytic paper are respectively assembled into a capacitor product without breakdown and ignition phenomena. Thus, the pressure resistance of the composite electrolytic paper with the thickness of 25 μm is equivalent to the safety and stability of the traditional electrolytic paper with the thickness of 30 μm.
While the invention has been described in detail and with reference to specific examples thereof, it will be apparent to one skilled in the art that various changes in the method can be made without departing from the spirit of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Claims (10)
1. A composite electrolytic paper for capacitors, comprising:
an electrolytic paper base film;
and a porous nanofiber membrane layer deposited on at least one surface of the electrolytic paper-based membrane;
wherein the porous nanofiber membrane is made of a high molecular polymer resistant to the temperature of more than 200 ℃.
2. The composite electrolytic paper for capacitors as claimed in claim 1, wherein the high molecular polymer is at least one of polyacrylonitrile, polyethylene, ethylene-vinyl acetate copolymer, polyimide, and polyamide.
3. The composite electrolytic paper for capacitors as claimed in claim 1, wherein the specific surface area of the composite electrolytic paper is 1 to 1000m2/g。
4. The composite electrolytic paper for capacitors as claimed in claim 1, wherein the thickness of the porous nanofiber membrane layer is 1 to 1000 μm, preferably 5 to 100 μm, more preferably 5 to 30 μm.
5. The composite electrolytic paper for capacitors as claimed in claim 1, wherein the average diameter of nanofibers in the porous nanofiber membrane layer is 50 to 600 nm; the nanofibers are cylindrical.
6. The composite electrolytic paper for capacitors as claimed in claim 1, wherein the thickness of the electrolytic paper-based film is 20 to 50 μm; the surface roughness of the base film of the electrolytic paper is 10-500 nm.
7. The method for producing a composite electrolytic paper for capacitors as claimed in any one of claims 1 to 6, characterized by comprising the steps of:
(1) preparing a spinning solution: stirring and dissolving a high molecular polymer in a solvent to obtain a spinning solution;
(2) electrostatic spinning: and (3) carrying out electrostatic spinning on the prepared spinning solution by taking electrolytic paper as a base film to obtain the composite electrolytic paper.
8. The method for preparing the composite electrolytic paper for capacitors as claimed in claim 7, wherein the spinning solution is present in an amount of 5 to 50% by mass; the solvent is at least one of ethyl acetate, formic acid, acetic acid, N-dimethylformamide, N-dimethylacetamide, toluene and tetrahydrofuran.
9. The method for producing a composite electrolytic paper for capacitors as claimed in claim 7, wherein the parameters of the electrospinning include: the positive high voltage is 20-100kV, the negative high voltage is-20- (-100) kV, the spinning distance is 15-40cm, the feeding speed of the spinning solution is 0.5-5L/h, and the winding speed is 0.1-10 m/min.
10. Capacitor, characterized in that it comprises the composite electrolytic paper according to any one of claims 1 to 6 or the composite electrolytic paper obtained by the production method according to any one of claims 7 to 9.
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