CN114709555A - Lithium ion battery diaphragm substrate and preparation method thereof - Google Patents
Lithium ion battery diaphragm substrate and preparation method thereof Download PDFInfo
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- CN114709555A CN114709555A CN202210386109.8A CN202210386109A CN114709555A CN 114709555 A CN114709555 A CN 114709555A CN 202210386109 A CN202210386109 A CN 202210386109A CN 114709555 A CN114709555 A CN 114709555A
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- 239000000758 substrate Substances 0.000 title claims abstract description 48
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 35
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 35
- 238000002360 preparation method Methods 0.000 title claims abstract description 8
- 239000000835 fiber Substances 0.000 claims abstract description 80
- 229920000433 Lyocell Polymers 0.000 claims abstract description 33
- 229920000728 polyester Polymers 0.000 claims abstract description 31
- 238000012216 screening Methods 0.000 claims abstract description 30
- 239000004745 nonwoven fabric Substances 0.000 claims abstract description 19
- 238000003490 calendering Methods 0.000 claims abstract description 17
- 238000001035 drying Methods 0.000 claims abstract description 16
- 238000000034 method Methods 0.000 claims abstract description 16
- 230000018044 dehydration Effects 0.000 claims abstract description 9
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 9
- 238000000151 deposition Methods 0.000 claims abstract description 9
- 238000000227 grinding Methods 0.000 claims abstract description 9
- 238000004513 sizing Methods 0.000 claims abstract description 8
- 238000004537 pulping Methods 0.000 claims description 11
- 238000007670 refining Methods 0.000 claims description 10
- 238000007865 diluting Methods 0.000 claims description 6
- 238000002156 mixing Methods 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 238000010009 beating Methods 0.000 claims description 2
- 238000007873 sieving Methods 0.000 claims description 2
- 239000011148 porous material Substances 0.000 abstract description 9
- 150000002500 ions Chemical class 0.000 abstract description 7
- 230000005540 biological transmission Effects 0.000 abstract description 4
- 239000000463 material Substances 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 9
- 238000012360 testing method Methods 0.000 description 9
- 239000002002 slurry Substances 0.000 description 7
- 238000007731 hot pressing Methods 0.000 description 3
- 238000011056 performance test Methods 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 206010061592 cardiac fibrillation Diseases 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000002600 fibrillogenic effect Effects 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 239000012982 microporous membrane Substances 0.000 description 2
- 239000002121 nanofiber Substances 0.000 description 2
- 229920000098 polyolefin Polymers 0.000 description 2
- 229920001169 thermoplastic Polymers 0.000 description 2
- 239000004416 thermosoftening plastic Substances 0.000 description 2
- 208000005156 Dehydration Diseases 0.000 description 1
- 229910013872 LiPF Inorganic materials 0.000 description 1
- 101150058243 Lipf gene Proteins 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000010485 coping Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000001453 impedance spectrum Methods 0.000 description 1
- 210000001724 microfibril Anatomy 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/403—Manufacturing processes of separators, membranes or diaphragms
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/411—Organic material
- H01M50/429—Natural polymers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/44—Fibrous material
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Cell Separators (AREA)
Abstract
The invention provides a preparation method of a lithium ion battery diaphragm substrate, which comprises the following steps: s1, grinding the tencel short fibers by grinding equipment to obtain a pulp 1; s2, screening the pulp 1 through a screening-grinding circulation system to obtain tencel fibrillated fibers with the maximum diameter smaller than 2.5 mu m; s3, sizing the tencel fibrillated fiber obtained in the step S2 by an open headbox at the concentration of 0.1% -0.3%, depositing the tencel fibrillated fiber on a polyester fiber non-woven fabric along an outer inclined plate of the open headbox, performing vacuum dehydration and squeezing to obtain a wet paper sheet, and drying the wet paper sheet by a drying cylinder to obtain a dry paper sheet; and S4, carrying out soft calendaring treatment on the dry paper to obtain the lithium ion battery diaphragm substrate. The lithium ion battery diaphragm substrate prepared by the method can prevent the polyester fiber from migrating into the pores of the fibrillated fiber by depositing the fibrillated fiber on the polyester fiber non-woven fabric in a papermaking mode, so that the ion transmission performance of the substrate can be improved, and the impedance of diaphragm ions can be reduced.
Description
Technical Field
The invention relates to the technical field of battery diaphragm manufacturing, in particular to a lithium ion battery diaphragm substrate and a preparation method thereof.
Background
The development of new energy automobiles is a necessary way for China to move from the automobile kingdom to the automobile forcing country, and is a strategic measure for coping with climate change and promoting green development. However, in recent years, the spontaneous combustion accidents of the electric automobiles are frequent, and the safety of the battery products becomes more and more important. Separator failure is a direct cause of thermal runaway in batteries. The polyolefin microporous membrane has excellent mechanical property, chemical stability and relatively uniform pore structure, and is a mainstream membrane in the current market. However, the polyolefin microporous membrane has low heat-resistant temperature and yield strength in the thickness direction, pores of the separator are easily closed and blocked under the action of heat and stress, the service life of the battery is shortened, and the safety risk is increased.
The non-woven fabric diaphragm has large aperture and high porosity, and the diaphragm can be endowed with excellent heat resistance and pressure resistance by selecting fibers with better heat resistance. Patent No. CN108598337B proposes that a double-layer one-step forming and hot-pressing process is adopted to prepare superfine trunk fibers, thermoplastic bonding fibers and nano fibers to obtain a base material with a supporting layer and a compact layer, however, the thermoplastic bonding fibers can migrate to the pores among the nano fibers in the hot-pressing process to cause local pore closure and influence the ion transmission performance, thereby greatly increasing the ionic impedance of the diaphragm.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a lithium ion battery diaphragm substrate and a preparation method thereof, wherein a fibrillation fiber is deposited on a polyester fiber non-woven fabric in a papermaking mode, so that the polyester fiber can be prevented from migrating into the pores of the fibrillation fiber, the ion transmission performance of the substrate can be improved, and the impedance of diaphragm ions can be reduced.
In order to realize the technical scheme, the invention provides a preparation method of a lithium ion battery diaphragm substrate, which specifically comprises the following steps:
s1, controlling the tencel chopped fibers to be 1-30% in concentration, and performing pulping treatment by using a first group of pulping equipment to obtain pulp 1 with the beating degree of 40-65 DEG SR;
s2, passing the pulp 1 through a screening-grinding circulation system, wherein the pulp passing through a screen of the last screening device is tencel fibrillated fiber with the maximum diameter smaller than 2.5 mu m;
s3, sizing the tencel fibrillated fiber obtained in the step S2 by an open headbox at the concentration of 0.1% -0.3%, depositing the tencel fibrillated fiber on a polyester fiber non-woven fabric along an outer inclined plate of the open headbox, performing vacuum dehydration and squeezing to obtain a wet paper sheet, and drying the wet paper sheet by a drying cylinder to obtain a dry paper sheet;
and S4, carrying out soft calendaring treatment on the dry paper to obtain the lithium ion battery diaphragm substrate.
Preferably, the operation steps of the sieving-refining circulation system in the step S2 are:
s21, diluting the concentration of the pulp 1 to 0.01-0.05% for screening treatment, screening by a group of screening devices, mixing the pulp intercepted by the screens of the group of screening devices to obtain pulp 2, and using the pulp passing through a 300-mesh screen of the last screening device as fibrillated fibers;
s22, diluting the pulp 2 to the concentration of 1-30%, and refining the pulp by a second group of refining equipment to 70-95 DEG SR to obtain pulp 3;
s23, mixing the pulp 3 and the pulp 1 to form a closed sieving-refining circulating system, and repeating the steps S21-S23 until the pulp passes through a 300-mesh screen of the last sieving device, so that the tencel fibrillated fiber with the maximum diameter of less than 2.5 mu m is obtained.
Preferably, the refining apparatus is one or more of a disc refiner, a conical refiner, a cylindrical refiner or a trough refiner.
Preferably, the screening device is formed by connecting a plurality of vibrating screens or filters in series, wherein the mesh number of the vibrating screens is increased sequentially.
Preferably, the screen mesh number of the screening device is 300 meshes, the screen mesh number of the first screening device is 100 meshes, the screen mesh number of the last screening device is 300 meshes, and the screen mesh number of the former screening device is smaller than that of the latter screening device.
Preferably, the soft calendering pressure in the step S4 is 80N/mm, and the temperature is less than 100 ℃.
The invention also provides a lithium ion battery diaphragm substrate prepared by the method, and the lithium ion battery diaphragm substrate comprises a polyester fiber non-woven fabric and a fibrillated fiber layer, wherein the thickness of the polyester fiber non-woven fabric is 10-18 mu m, the thickness of the fibrillated fiber layer is 2-5 mu m, the fibrillated fiber layer consists of 100% of tencel fibrillated fibers, and the maximum diameter of the tencel fibrillated fibers is less than 2.5 mu m.
Preferably, the polyester fiber non-woven fabric has a longitudinal tensile strength of more than 500N/m.
The lithium ion battery diaphragm substrate and the device provided by the invention have the beneficial effects that:
(1) according to the invention, the fibrillated fiber is deposited on the polyester fiber non-woven fabric in a papermaking mode, so that the polyester fiber can be prevented from migrating into the pores of the fibrillated fiber, the ion transmission of the base material can be improved, and the impedance of diaphragm ions is reduced;
(2) the maximum diameter of the fibrillated fiber used in the invention is less than 2.5 μm, which is beneficial to ensuring the uniformity of the thickness of the base material;
(3) the diaphragm base material does not shrink at 200 ℃, and still has certain hot air strength at 300 ℃;
(4) according to the invention, the maximum diameter of the fibrillated fiber is smaller than 2.5 μm by screening and pulping, the main fiber with the diameter larger than 2.5 μm is separated out by screening, and the main fiber with the diameter larger than 2.5 μm is only ground by the second group of pulping equipment, so that the pulping energy consumption can be saved, the microfibril proportion is reduced, and the diaphragm ionic impedance is reduced.
Drawings
FIG. 1 is a schematic process flow diagram of the present invention.
Fig. 2 is a flow chart of the preparation of the tencel fibrillated fiber in the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by a person skilled in the art without making any inventive step are within the scope of the present invention.
Example 1
A lithium ion battery diaphragm substrate is prepared by the following method:
(1) controlling the tencel chopped fibers (with the length of 4mm and the diameter of 12 microns) at the concentration of 4%, and performing pulping treatment by using three disc mill pulping devices with the pulping power of 180kw to obtain pulp 1 with the pulping degree of 40-degree SR;
(2) diluting the concentration of the slurry 1 to 0.03%, screening, sequentially passing through three screening machines with screens of 100 meshes, 200 meshes and 300 meshes, and mixing the slurry retained by the screens of the three screening machines to obtain slurry 2; then diluting the pulp 2 to 20% of concentration, and performing pulp grinding treatment by using three disc grinders with the pulp grinding power of 180kw to obtain pulp 3 with the pulp grinding degree of 95-degree SR; then mixing the pulp 3 with the pulp 1 to form a closed screening-grinding circulation system until all the pulp passes through a 300-mesh screen to obtain the pulp which is tencel fibrillated fiber with the maximum diameter less than 2.5 mu m;
(3) controlling the concentration of tencel fibrillated fiber pulp to be 0.1%, sizing by an open flow box, depositing on polyester fiber non-woven fabric with the thickness of 10 mu m along an outer inclined plate of the open flow box, performing vacuum dehydration and squeezing to obtain wet paper, and drying the wet paper by a drying cylinder to obtain dry paper;
(4) the dry paper sheet is subjected to soft calendaring treatment to obtain the lithium ion battery diaphragm substrate, wherein the soft calendaring pressure is 80N/mm, and the temperature is less than 100 ℃.
Example 2
A lithium ion battery diaphragm substrate is prepared by the following method:
(1) and (2) the steps are the same as example 1;
(3) controlling the concentration of tencel fibrillated fiber pulp to be 0.25%, sizing by an open flow box, depositing on a polyester fiber non-woven fabric with the thickness of 18 mu m along an outer inclined plate of the open flow box, performing vacuum dehydration and squeezing to obtain a wet paper sheet, and drying the wet paper sheet by a drying cylinder to obtain a dry paper sheet;
(4) the dry paper sheet is subjected to soft calendaring treatment to obtain the lithium ion battery diaphragm substrate, wherein the soft calendaring pressure is 80N/mm, and the temperature is less than 100 ℃.
Comparative example 1
A lithium ion battery diaphragm substrate is prepared by the following method:
(1) and (2) the steps are the same as example 1;
(3) controlling the concentration of tencel fibrillated fiber pulp to be 0.25%, sizing by an open flow box, depositing on polyester fiber non-woven fabric with the thickness of 8 mu m along an outer inclined plate of the open flow box, performing vacuum dehydration and squeezing to obtain wet paper, and drying the wet paper by a drying cylinder to obtain dry paper;
(4) the dry paper sheet is subjected to soft calendaring treatment to obtain the lithium ion battery diaphragm substrate, wherein the soft calendaring pressure is 80N/mm, and the temperature is less than 100 ℃.
Comparative example 2
A lithium ion battery diaphragm substrate is prepared by the following method:
(1) and (2) the steps are the same as example 1;
(3) controlling the concentration of tencel fibrillated fiber pulp to be 0.3%, sizing by an open flow box, depositing on a polyester fiber non-woven fabric with the thickness of 18 mu m along an outer inclined plate of the open flow box, performing vacuum dehydration and squeezing to obtain a wet paper sheet, and drying the wet paper sheet by a drying cylinder to obtain a dry paper sheet;
(4) the dry paper sheet is subjected to soft calendaring treatment to obtain the lithium ion battery diaphragm substrate, wherein the soft calendaring pressure is 80N/mm, and the temperature is less than 100 ℃.
Comparative example 3
A lithium ion battery diaphragm substrate is prepared by the following method:
(1) and (2) the steps are the same as example 1;
(3) controlling the concentration of tencel fibrillated fiber pulp to be 0.05%, sizing by an open flow box, depositing on a polyester fiber non-woven fabric with the thickness of 18 mu m along an outer inclined plate of the open flow box, performing vacuum dehydration and squeezing to obtain a wet paper sheet, and drying the wet paper sheet by a drying cylinder to obtain a dry paper sheet;
(4) the dry paper sheet is subjected to soft calendaring treatment to obtain the lithium ion battery diaphragm substrate, wherein the soft calendaring pressure is 80N/mm, and the temperature is less than 100 ℃.
Comparative example 4
A lithium ion battery diaphragm substrate is prepared by the following method:
(1) and (2) the steps are the same as example 1;
(3) the polyester layer comprises drawn polyester fiber and undrawn polyester fiber, and the ratio of the drawn polyester fiber to the undrawn polyester fiber is 6: 4. the quantitative ratio of the polyester fiber layer to the tencel layer is 6: 2. Feeding the diluted slurry of the polyester layer and the tencel layer into a double-layer hydraulic former for pulp distribution, wherein the slurry of the tencel layer enters an upper flow channel, the slurry of the polyester layer enters a flow channel close to a forming net, the slurry flows of the flow channels are sequentially laminated in the same region and simultaneously subjected to papermaking and forming, and wet paper sheets are obtained through dehydration treatment;
(4) and (3) obtaining a dry paper sheet after the wet paper sheet passes through a Yankee cylinder, and obtaining the lithium ion battery diaphragm substrate after the dry paper sheet is subjected to soft calendering treatment, wherein the soft calendering pressure is 80N/mm, and the temperature is 220 ℃.
Substrate Performance testing
The substrates prepared in examples 1 and 2 and comparative examples 1 to 3 were subjected to performance tests, the test items and methods were as follows:
1. thickness: the thickness of the substrate is measured by L&The test was carried out by a No.251 thickness tester available from the company W, and the area of the test sample was 200mm2。
2. The tensile strength of the substrate was measured by using a universal tensile tester available from INSTRON corporation, and the test specimen had a size of 1.5cm X4 cm and a test speed of 5 mm/min.
3. Hot air strength performance test of base material at 300 deg.c
A sample of the membrane having a length of 10cm or more is taken, and both ends of the substrate are fixed to a movable frame in a tensioned state. And (3) starting a hot air gun to preheat to a specified temperature, moving the substrate sample to a position 3cm away from the gun head of the hot air gun, enabling the sample to be vertical to the gun head, recording the damage time of the substrate, and evaluating the hot air strength performance according to the following standard.
O: the base material is not damaged after being treated by hot air for 4 min;
x: the base material is damaged after being treated by hot air for less than 4 min.
4. Substrate curl height test
A substrate sample having a size of 5cm by 5cm was cut out and placed on a horizontal table top, and the height of the curled end from the table top was measured.
O: the curling height of the base material is less than or equal to 5 mm;
x: the substrate curl height is greater than 5 mm.
5. Diaphragm ionic impedance testing
The electrolyte (L mol/L LiPF)6EC/DMC) wetted diaphragm disk (diameter: 16mm) was sandwiched between two stainless steel sheets as working and reference electrodes to form a stainless steel sheet/diaphragm/stainless steel sheet system, and tested on electrochemical workstation CHI604E by AC impedance method at initial voltage of 0V and scanning frequency of 0-105Hz. The real axis impedance value at the intersection point of the curve and the real axis in the alternating current impedance spectrum is the diaphragm ionic impedance, and the test temperature is 30 ℃.
TABLE 1 Performance test parameters for lithium ion battery separator substrates of the present invention
As can be seen from Table 1, the thickness of the inventive examples 1, 2 is less than or equal to 23 μm, the tensile strength is greater than 500N/m, and the inventive examples have better hot wind strength and crimp height. The polyester fiber non-woven fabric of comparative example 1 has a low thickness, and the strength of the obtained base material is less than 500N/m; the fibrillated fiber layer of comparative example 2 has a large amount of use, and the substrate has a large crimp height due to the difference in water absorption properties of the two layers, which is not conducive to subsequent coating processing; the fibrillated fibers of comparative example 3 were used in an excessively small amount, and the base material had poor hot wind strength properties at 300 ℃. The polyester fiber and the tencel fiber of comparative example 4 were simultaneously dehydrated and formed, and as the pore diameter of the tencel layer was small, the undrawn polyester fiber migrated toward the tencel layer under the capillary force between the tencel fibers in the hot pressing process to block the pores, and a large ionic resistance was obtained.
The above description is only for the preferred embodiment of the present invention, but the present invention should not be limited to the embodiment and the disclosure of the drawings, and therefore, all equivalent or modifications that do not depart from the spirit of the present invention are intended to fall within the scope of the present invention.
Claims (8)
1. A preparation method of a lithium ion battery diaphragm substrate is characterized by comprising the following steps:
s1, controlling the tencel chopped fibers to be 1-30% in concentration, and performing pulping treatment by using a first group of pulping equipment to obtain pulp 1 with the beating degree of 40-65 DEG SR;
s2, passing the pulp 1 through a screening-grinding circulation system, wherein the pulp passing through a screen of the last screening device is tencel fibrillated fiber with the maximum diameter smaller than 2.5 mu m;
s3, sizing the tencel fibrillated fibers obtained in the step S2 by an open headbox at the concentration of 0.1% -0.3%, depositing the tencel fibrillated fibers on polyester fiber non-woven fabrics along an outer inclined plate of the open headbox, performing vacuum dehydration and squeezing to obtain wet paper sheets, and drying the wet paper sheets by a drying cylinder to obtain dry paper sheets;
and S4, carrying out soft calendaring treatment on the dry paper to obtain the lithium ion battery diaphragm substrate.
2. The method for preparing a lithium ion battery membrane-separating substrate according to claim 1, wherein the operation steps of the sieving-refining circulation system in the step S2 are as follows:
s21, diluting the concentration of the pulp 1 to 0.01-0.05% for screening treatment, screening by a group of screening devices, mixing the pulp intercepted by the screens of the group of screening devices to obtain pulp 2, and using the pulp passing through a 300-mesh screen of the last screening device as fibrillated fibers;
s22, diluting the pulp 2 to the concentration of 1-30%, and refining the pulp by a second group of refining equipment to 70-95 DEG SR to obtain pulp 3;
s23, mixing the pulp 3 and the pulp 1 to form a closed sieving-refining circulating system, and repeating the steps S21-S23 until the pulp passes through a 300-mesh screen of the last sieving device, so that the tencel fibrillated fiber with the maximum diameter of less than 2.5 mu m is obtained.
3. The method of making a lithium ion battery separator substrate according to claim 2, wherein: the refining equipment is one or more of a disc refiner, a conical refiner, a cylindrical refiner or a trough refiner.
4. The method of making a lithium ion battery separator substrate according to claim 2, wherein: the screening equipment is formed by connecting a plurality of vibrating screens or filters in series, wherein the mesh number of the vibrating screens is increased in sequence.
5. The method of making a lithium ion battery separator substrate according to claim 2, wherein: the screen mesh number of the screening equipment is 100-300 meshes, the screen mesh number of the first screening equipment is 100 meshes, the screen mesh number of the last screening equipment is 300 meshes, and the screen mesh number of the former screening equipment is smaller than that of the latter screening equipment.
6. The method of making a lithium ion battery separator substrate according to claim 1, wherein: in the step S4, the soft calendering pressure is 80N/mm, and the temperature is less than 100 ℃.
7. A lithium ion battery separator substrate, characterized in that: the lithium ion battery diaphragm substrate prepared by the method of any one of claims 1-6, which comprises a polyester fiber non-woven fabric and a fibrillated fiber layer, wherein the polyester fiber non-woven fabric is 10-18 μm thick, the fibrillated fiber layer is 2-5 μm thick, the fibrillated fiber layer is composed of 100% tencel fibrillated fibers, and the maximum diameter of the tencel fibrillated fibers is less than 2.5 μm.
8. The lithium ion battery separator substrate of claim 7, wherein: the longitudinal tensile strength of the polyester fiber non-woven fabric is more than 500N/m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210386109.8A CN114709555A (en) | 2022-04-13 | 2022-04-13 | Lithium ion battery diaphragm substrate and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210386109.8A CN114709555A (en) | 2022-04-13 | 2022-04-13 | Lithium ion battery diaphragm substrate and preparation method thereof |
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| Publication Number | Publication Date |
|---|---|
| CN114709555A true CN114709555A (en) | 2022-07-05 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210386109.8A Withdrawn CN114709555A (en) | 2022-04-13 | 2022-04-13 | Lithium ion battery diaphragm substrate and preparation method thereof |
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- 2022-04-13 CN CN202210386109.8A patent/CN114709555A/en not_active Withdrawn
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Application publication date: 20220705 |