CN112332028A - Functional lithium battery diaphragm slurry, functional lithium battery diaphragm and lithium battery - Google Patents
Functional lithium battery diaphragm slurry, functional lithium battery diaphragm and lithium battery Download PDFInfo
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- CN112332028A CN112332028A CN202011044508.3A CN202011044508A CN112332028A CN 112332028 A CN112332028 A CN 112332028A CN 202011044508 A CN202011044508 A CN 202011044508A CN 112332028 A CN112332028 A CN 112332028A
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 91
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 91
- 239000002002 slurry Substances 0.000 title claims abstract description 29
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 claims abstract description 34
- 239000002033 PVDF binder Substances 0.000 claims abstract description 18
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims abstract description 18
- 239000004793 Polystyrene Substances 0.000 claims abstract description 17
- 239000000839 emulsion Substances 0.000 claims abstract description 17
- 229920002223 polystyrene Polymers 0.000 claims abstract description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000002270 dispersing agent Substances 0.000 claims abstract description 11
- 239000002562 thickening agent Substances 0.000 claims abstract description 11
- 239000000843 powder Substances 0.000 claims abstract description 10
- 239000008367 deionised water Substances 0.000 claims abstract description 9
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 9
- 239000011230 binding agent Substances 0.000 claims abstract description 7
- 239000002994 raw material Substances 0.000 claims abstract description 4
- 238000003756 stirring Methods 0.000 claims description 48
- 239000011248 coating agent Substances 0.000 claims description 36
- 238000000576 coating method Methods 0.000 claims description 36
- 239000003792 electrolyte Substances 0.000 claims description 26
- -1 fatty acids ethylene oxide Chemical class 0.000 claims description 17
- 239000000203 mixture Substances 0.000 claims description 10
- 239000004698 Polyethylene Substances 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 9
- 229920000573 polyethylene Polymers 0.000 claims description 9
- 230000008569 process Effects 0.000 claims description 7
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 claims description 6
- 235000014113 dietary fatty acids Nutrition 0.000 claims description 6
- 239000000194 fatty acid Substances 0.000 claims description 6
- 229930195729 fatty acid Natural products 0.000 claims description 6
- 239000011259 mixed solution Substances 0.000 claims description 6
- 229920000058 polyacrylate Polymers 0.000 claims description 5
- 239000002202 Polyethylene glycol Substances 0.000 claims description 4
- 239000004743 Polypropylene Substances 0.000 claims description 4
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 claims description 4
- 229920002037 poly(vinyl butyral) polymer Polymers 0.000 claims description 4
- 229920001223 polyethylene glycol Polymers 0.000 claims description 4
- 229920001155 polypropylene Polymers 0.000 claims description 4
- 238000007763 reverse roll coating Methods 0.000 claims description 4
- 239000011247 coating layer Substances 0.000 claims description 3
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 2
- 239000004745 nonwoven fabric Substances 0.000 claims description 2
- 238000004528 spin coating Methods 0.000 claims 2
- 229920003123 carboxymethyl cellulose sodium Polymers 0.000 claims 1
- 229940063834 carboxymethylcellulose sodium Drugs 0.000 claims 1
- 230000002035 prolonged effect Effects 0.000 abstract description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical group CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 20
- 238000001035 drying Methods 0.000 description 17
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 9
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 7
- 238000010521 absorption reaction Methods 0.000 description 7
- 239000000853 adhesive Substances 0.000 description 7
- 230000001070 adhesive effect Effects 0.000 description 7
- 229910021383 artificial graphite Inorganic materials 0.000 description 7
- 239000007788 liquid Substances 0.000 description 7
- 230000035699 permeability Effects 0.000 description 7
- 239000007774 positive electrode material Substances 0.000 description 7
- 238000005507 spraying Methods 0.000 description 7
- 239000007773 negative electrode material Substances 0.000 description 6
- 238000005303 weighing Methods 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 238000001514 detection method Methods 0.000 description 4
- 230000000903 blocking effect Effects 0.000 description 3
- 239000001768 carboxy methyl cellulose Substances 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 3
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000005524 ceramic coating Methods 0.000 description 2
- 238000005034 decoration Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000007731 hot pressing Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 206010067484 Adverse reaction Diseases 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- 230000006838 adverse reaction Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920001495 poly(sodium acrylate) polymer Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- NNMHYFLPFNGQFZ-UHFFFAOYSA-M sodium polyacrylate Polymers [Na+].[O-]C(=O)C=C NNMHYFLPFNGQFZ-UHFFFAOYSA-M 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Cell Separators (AREA)
- Secondary Cells (AREA)
Abstract
The invention discloses functional lithium battery diaphragm slurry which comprises the following raw materials in parts by mass: 5-10 parts of polystyrene butadiene emulsion, 5-7 parts of PVDF powder, 1-3 parts of dispersant, 50-100 parts of thickener, 1-10 parts of binder and 50-100 parts of deionized water. By adding the polystyrene butadiene emulsion, the binding power between the lithium battery diaphragm and the battery cathode is effectively improved, and the cycle life of the lithium battery is prolonged.
Description
Technical Field
The invention relates to the technical field of lithium battery diaphragms, in particular to functional lithium battery diaphragm slurry, a functional lithium battery diaphragm and a lithium battery.
Background
The main structure of the lithium battery is divided into an anode, a cathode, electrolyte and a diaphragm, wherein the diaphragm can isolate short circuit caused by anode and cathode contact and provide a migration channel for lithium ions in the charging and discharging process. The traditional lithium battery diaphragm mostly adopts a microporous Polyethylene (PE) or polypropylene (PP) diaphragm, and with the improvement of the performance requirement of the battery, the simple common diaphragm is difficult to meet the requirement.
Mainstream products in the market comprise a PDVF coating diaphragm (spraying), a ceramic coating diaphragm, a PVDF ceramic composite diaphragm and the like, the PDVF coating mainly provides interface adhesion and increases the hardness of an electric core, the ceramic coating mainly provides good safety performance, a pure PVDF coating can only improve the interface adhesion between the diaphragm and a positive plate, and the improvement effect of the PVDF on a negative plate is not obvious due to poor adsorption on the graphite surface, so that the cycle life of a battery can be influenced, and the assembly efficiency of the battery is reduced.
Disclosure of Invention
The invention aims to provide functional lithium battery diaphragm slurry aiming at the technical defect that the improvement effect of the interface bonding force between a PVDF diaphragm and a negative plate is poor in the prior art.
The invention also aims to provide a functional lithium battery diaphragm formed by coating the functional lithium battery diaphragm slurry.
The invention also aims to provide a lithium battery consisting of the functional lithium battery diaphragm.
The technical scheme adopted for realizing the purpose of the invention is as follows:
a functional lithium battery diaphragm slurry comprises the following raw materials in parts by weight:
5-10 parts of polystyrene butadiene emulsion, 5-7 parts of PVDF powder, 1-3 parts of dispersant, 50-100 parts of thickener, 1-10 parts of binder and 50-100 parts of deionized water.
In the technical scheme, the dispersing agent comprises one or a mixture of fatty acid ethylene oxide and polyethylene glycol in any proportion; the thickening agent comprises one or a mixture of any proportion of sodium carboxymethylcellulose, polyacrylate and polyethylene oxide; the binder is one or a mixture of acrylate and polyvinyl butyral in any proportion.
In the above technical scheme, the preparation method comprises the following steps:
step 1: adding a dispersing agent into deionized water, and uniformly stirring to obtain a mixed solution;
step 2: adding PVDF powder into the mixed solution obtained in the step (1) and then uniformly stirring;
and step 3: adding the thickening agent and then uniformly stirring;
and 4, step 4: adding the binder and stirring uniformly;
and 5: adding the polystyrene butadiene emulsion, and uniformly dispersing to obtain the functional lithium battery diaphragm slurry.
In another aspect of the present invention, a functional lithium battery separator includes a base film and a coating layer formed by coating the above functional lithium battery separator slurry on one or both sides of the base film.
In the above technical solution, the base film includes one of a polypropylene base film, a polyethylene base film and a non-woven fabric base film.
In the technical scheme, the coating mode is rotary spraying or reverse micro-gravure roll coating.
In the technical scheme, in the rotary spraying process, the speed is 35-60m/min, the rotor rotating speed is 6500-10000r/min, and the feed pump speed is 650-900 ml/min.
In the technical scheme, in the reverse roll coating process of the micro-gravure, the speed is 35-60m/min, and the speed ratio of a coating roll is 100-130%.
In the above technical solution, the thickness of the coating is 0.5-5 μm.
In another aspect of the present invention, a lithium battery includes a positive electrode, a negative electrode, an electrolyte, and the functional lithium battery separator. The positive electrode material uses sublimed sulfur, the negative electrode uses artificial graphite, the electrolyte uses ethylene glycol dimethyl ether, and the electrolyte is diethyl ether.
Compared with the prior art, the invention has the beneficial effects that:
1. the functional lithium battery diaphragm slurry disclosed by the invention effectively improves the binding force between the lithium battery diaphragm and the battery cathode and prolongs the cycle life of the lithium battery by adding the polystyrene butadiene emulsion.
2. The liquid absorption amount of the functional lithium battery diaphragm disclosed by the invention is obviously increased so as to ensure that ions pass through the diaphragm without resistance. In a battery system, a large amount of electrolyte is consumed by cyclic charge and discharge, and therefore, sufficient storage is required. After the liquid absorption amount is increased, the cycle life of the battery is correspondingly prolonged.
3. The functional lithium battery diaphragm disclosed by the invention has good air permeability.
Detailed Description
The present invention will be described in further detail with reference to specific examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The raw material performance parameters used in the following examples are as follows:
polystyrene butadiene emulsion with solid content of 50 +/-1, viscosity of 100-350, pH value of 6-7, glass transition temperature of 5 ℃, Nippon Power technology Limited of New county;
PVDF powder with the number average molecular weight of 500000-1000000, the particle size of 50-300nm, high purity, Achima;
fatty acid ethylene oxide, nonionic, HLB value 18.5-19, haian petrochemical plant;
polyacrylate with number average molecular weight of 3000-5000 ten thousand and source wetting chemical;
acrylate with solid content of 15 +/-0.5, and developing a new energy source;
sodium carboxymethylcellulose, number average molecular weight 2000-;
polyvinyl butyral, a celestial material;
polyethylene glycol, new Yinuo Material, Qingdao, Ltd.
The performance parameter detection method in the following examples is as follows:
the thickness detection method comprises the following steps: a contact head of a Mark thickness gauge (German Mahr full-automatic film thickness gauge, model C1216M-AT) is a flat head, 1 point is measured AT intervals of 5cm along the TD (transverse) direction of a diaphragm, and 10 points are measured in total to calculate the average value;
the air permeability detection method comprises the following steps: measuring one point every 5cm along the TD (transverse direction) direction of the diaphragm by using a diaphragm air permeability tester (model BTY-B2P, Vinan Languang electromechanical technology, Ltd.), and measuring 5 points in total to obtain an average value;
the battery cycle life testing method comprises the following steps: sublimed sulfur is used as a positive electrode material, artificial graphite is used as a negative electrode material, ethylene glycol dimethyl ether is used as electrolyte, and ethyl ether (with the concentration of 3.6% -6.5%) is used as electrolyte to assemble a battery for testing;
the liquid absorption amount detection method comprises the following steps: cutting the diaphragm into 40 × 60mm, weighing by using an electronic balance, recording the weight, soaking the diaphragm in the electrolyte for three hours, taking out the diaphragm and weighing by using the electronic balance, and obtaining the difference value by subtracting the front weight and the rear weight as the liquid absorption amount.
The method for testing the bonding force between the diaphragm and the negative electrode comprises the following steps:
step 1: pre-drying the functional lithium battery diaphragm and the pole piece: cutting a functional lithium battery diaphragm with the width of 15mm and the length of 250 mm; cutting a pole piece with the width of 25mm and the length of 90mm, and pre-drying at the temperature of 105 ℃ for 15 h.
Step 2: attaching a functional lithium battery diaphragm to a pole piece, wherein a coating of the functional lithium battery diaphragm faces the direction of the pole piece to obtain a sample, putting the sample into a hot press (model: AN9637HS), fixing the sample on a steel plate by using a double-sided adhesive after hot pressing, wherein the hot pressing parameter is 80 ℃, the pressure is 0.3Mpa, and the time is 20s, so as to form the steel plate-the double-sided adhesive tape-the pole piece-the diaphragm;
and step 3: peeling test parameters were carried out using an electronic tensile machine (model: AGS-X-100N) at a peeling speed of 100mm/min and a peeling effective length of 70mm, and the test was repeated at least three times to obtain an average value.
Example 1
A preparation method of functional lithium battery diaphragm slurry comprises the following steps:
step 1: weighing 2 parts by mass of dispersant fatty acid ethylene oxide and 80 parts by mass of deionized water, and putting into a stirring tank (model HY-DLH43L, lucky machine) for uniformly stirring at a stirring speed of 350r/min for 30 min;
step 2: adding 6 parts by mass of PVDF powder into the mixed solution in the step 1, and continuing stirring for 30min at a stirring speed of 450 r/min;
and step 3: adding 76 parts by mass of thickening agent polyacrylate, and continuously stirring for 10min at the stirring speed of 500 r/min;
and 4, step 4: adding 4 parts by mass of adhesive acrylate, and continuously stirring for 10min at the stirring speed of 500 r/min;
and 5: and 6 parts by mass of polystyrene butadiene emulsion is added, the mixture is continuously stirred for 10min at the stirring speed of 500r/min, and the No. 1 functional lithium battery diaphragm slurry is obtained.
Coating the functional lithium battery diaphragm slurry on one side of a polyethylene base film with the thickness of 12 mu m in a rotary spraying mode, wherein the thickness of the coating is 1.5 mu m, the speed of the vehicle is 50m/min, the rotating speed of a rotor is 7500r/min, the speed of a feeding pump is 850ml/min, the coating is finished, then drying is carried out in a drying oven, the temperature of the drying oven is 45-55-60-55-45 ℃, and then the coating is rolled to obtain the No. 1 functional lithium battery diaphragm.
A lithium battery comprises a positive electrode, a negative electrode, an electrolyte and the No. 1 functional lithium battery diaphragm. The positive electrode material is sublimed sulfur, the negative electrode material is artificial graphite, the electrolyte is ethylene glycol dimethyl ether, and the electrolyte is diethyl ether with the concentration of 3.6 wt%.
Comparative example 1
A preparation method of lithium battery diaphragm slurry (PVDF water system slurry) comprises the following steps:
step 1: weighing 2 parts by mass of dispersant fatty acid ethylene oxide and 80 parts by mass of deionized water, and putting the mixture into a stirring tank (good operation) to be uniformly stirred at the stirring speed of 350r/min for 30 min;
step 2: adding 6 parts by mass of PVDF powder into the mixed solution in the step 1, and continuing stirring for 30min at a stirring speed of 450 r/min;
and step 3: adding 76 parts by mass of thickening agent polyacrylate, and continuously stirring for 10min at the stirring speed of 500 r/min;
and 4, step 4: adding 4 parts by mass of adhesive acrylate, and continuously stirring for 10min at the stirring speed of 500 r/min; and obtaining No. 1a lithium battery diaphragm slurry.
Coating the lithium battery diaphragm slurry on one side of a polyethylene base film with the thickness of 12 mu m in a rotary spraying mode, wherein the thickness of the coating is 1.5 mu m, the speed of the vehicle is 50m/min, the rotating speed of a rotor is 7500r/min, the speed of a feeding pump is 850ml/min, the coating is finished, then drying is carried out in a drying oven, the temperature of the drying oven is 45-55-60-55-45 ℃, and then the coating is rolled to obtain the No. 1a lithium battery diaphragm.
A lithium battery comprises a positive electrode, a negative electrode, an electrolyte and the No. 1a lithium battery diaphragm. The positive electrode material is sublimed sulfur, the negative electrode material is artificial graphite, the electrolyte is ethylene glycol dimethyl ether, and the electrolyte is diethyl ether with the concentration of 3.6 wt%.
Example 2
A preparation method of functional lithium battery diaphragm slurry comprises the following steps:
step 1: weighing 1 part by mass of dispersant fatty acid ethylene oxide and 55 parts by mass of deionized water, putting into a stirring tank (good operation), and stirring uniformly at the stirring speed of 350r/min for 30 min;
step 2: adding 7 parts by mass of PVDF powder into the mixture obtained in the step 1, and continuing stirring for 30min at a stirring speed of 450 r/min;
and step 3: adding 98 parts by mass of thickener sodium carboxymethylcellulose, and continuously stirring for 10min at the stirring speed of 500 r/min;
and 4, step 4: adding 4 parts by mass of adhesive polyvinyl butyral, and continuously stirring for 10min at the stirring speed of 500 r/min;
and 5: and adding 6 parts by mass of polystyrene butadiene emulsion, and continuously stirring for 10min at the stirring speed of 500r/min to obtain No. 2 functional lithium battery diaphragm slurry.
Coating the functional lithium battery diaphragm slurry on one side of a polyethylene base film with the thickness of 12 mu m in a rotary spraying mode, wherein the thickness of the coating is 2.5 mu m, the vehicle speed is 50m/min, the rotor rotating speed is 9500r/min, the feeding pump speed is 850ml/min, after the coating is finished, drying is carried out in a drying oven, and after the drying oven is dried at the temperature of 45-55-60-55-45 ℃, the No. 2 functional lithium battery diaphragm is obtained by rolling.
A lithium battery comprises a positive electrode, a negative electrode, an electrolyte and the No. 2 functional lithium battery diaphragm. The positive electrode material is sublimed sulfur, the negative electrode material is artificial graphite, the electrolyte is ethylene glycol dimethyl ether, and the electrolyte is diethyl ether with the concentration of 3.6 wt%.
Comparative example 2
Coating polystyrene butadiene emulsion on one side of a polyethylene base film with the thickness of 12 mu m in a rotary spraying mode, wherein the thickness of the coating is 2.5 mu m, the speed of the vehicle is 50m/min, the rotating speed of a rotor is 9500r/min, the speed of a feeding pump is 850ml/min, drying is carried out in a drying oven after the coating is finished, and the number 2a lithium battery diaphragm is obtained after the drying is carried out at the temperature of 45-55-60-55-45 ℃.
A lithium battery comprises a positive electrode, a negative electrode, an electrolyte and the No. 2a lithium battery diaphragm. The positive electrode material is sublimed sulfur, the negative electrode material is artificial graphite, the electrolyte is ethylene glycol dimethyl ether, and the electrolyte is diethyl ether with the concentration of 3.6 wt%.
Example 3
A preparation method of functional lithium battery diaphragm slurry comprises the following steps:
step 1: weighing 1 part by mass of dispersant polyethylene glycol and 55 parts by mass of deionized water, putting into a stirring tank (good operation), and stirring uniformly at a stirring speed of 350r/min for 30 min;
step 2: adding 7 parts by mass of PVDF powder into the mixture obtained in the step 1, and continuing stirring for 30min at a stirring speed of 450 r/min;
and step 3: adding 98 parts by mass of thickener polyacrylate, and continuously stirring for 10min at the stirring speed of 500 r/min;
and 4, step 4: adding 6 parts by mass of adhesive acrylate, and continuously stirring for 10min at the stirring speed of 500 r/min;
and 5: and adding 6 parts by mass of polystyrene butadiene emulsion, and continuously stirring for 10min at the stirring speed of 500r/min to obtain No. 3 functional lithium battery diaphragm slurry.
Coating the functional lithium battery diaphragm slurry on two sides of a polyethylene base film with the thickness of 12 mu m in a micro-gravure reverse roll coating mode, wherein the thickness of the coating on each side is 2.5 mu m, the vehicle speed is 50m/min, the speed ratio of a coating roll is 130%, drying the coating in a drying oven after the coating is finished, and winding the coating after the drying oven is dried at the temperature of 45-55-60-55-45 ℃ to obtain the No. 3 functional lithium battery diaphragm.
A lithium battery comprises a positive electrode, a negative electrode, electrolyte and the No. 3 functional lithium battery diaphragm. The positive electrode material is sublimed sulfur, the negative electrode material is artificial graphite, the electrolyte is ethylene glycol dimethyl ether, and the electrolyte is diethyl ether with the concentration of 6.5 wt%.
The performance parameters of the functional lithium battery separators or lithium battery separators prepared in the above examples and comparative examples are shown in the following table:
| diaphragm numbering | Coating thickness μm | Air permeability s/100ml | Liquid absorption amount g | Adhesive force N |
| 1 | 1.5 | 108 | 3 | 3.827 |
| 1a | 1.5 | 203 | 1.5 | 1.693 |
| 2 | 2.5 | 143 | 4.23 | 4.249 |
| 2a | 2.5 | 238 | 2 | 4.198 |
| 3 | 2.5+2.5 | 139 | 4.9 | 3.991 |
As can be seen from the above table, the functional lithium battery separators prepared in examples 1 to 3 have significantly improved adhesion to the negative electrode as compared to the lithium battery separator prepared in comparative example 1, indicating that the addition of the polystyrene butadiene emulsion can effectively improve the adhesion between the lithium battery separator and the negative electrode. Meanwhile, compared with the lithium battery separators prepared in comparative examples 1 and 2, the liquid absorption amount of the functional lithium battery separators prepared in examples 1 to 3 is significantly increased, because the polystyrene butadiene emulsion and the PVDF have good wettability under the synergistic effect, the affinity of the separators and the electrolyte is improved, the contact area between the separators and the electrolyte is enlarged, and the liquid absorption performance is improved.
The functional lithium battery separator prepared in example 1 has improved air permeability compared to the lithium battery separator prepared in comparative example 1, because the separator is aggregated after being coated with only PVDF aqueous slurry, and the phenomenon of pore blocking occurs. After the polystyrene butadiene emulsion and the water system PVDF slurry are dispersed and stirred, the polystyrene butadiene emulsion can be coated on the water system PDVF slurry, so that the phenomenon of hole blocking is avoided, and the air permeability is improved. The functional lithium battery separator prepared in example 2 has improved air permeability compared to the lithium battery separator prepared in comparative example 2. The reason is that the surface of the diaphragm is fully paved to cause the phenomenon of hole blocking by simply coating the polystyrene butadiene emulsion, so that the ventilation value of the diaphragm is large.
The performance parameters of the lithium batteries prepared in the above examples and comparative examples are shown in the following table:
as can be seen from the above table, the lithium batteries prepared from the functional lithium battery separators prepared in examples 1 to 3 have improved capacity retention rates and prolonged life spans compared to the lithium batteries prepared in comparative examples 1 and 2. The reason is that the diaphragm is tightly adhered to the surface of the cathode, so that adverse reaction in the battery circulation process is reduced, and material loss is reduced.
The functional lithium battery coating separator of the present invention was prepared according to the present disclosure by adjusting the process parameters and exhibited substantially the same properties as example 1.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. The functional lithium battery diaphragm slurry is characterized by comprising the following raw materials in parts by mass:
5-10 parts of polystyrene butadiene emulsion, 5-7 parts of PVDF powder, 1-3 parts of dispersant, 50-100 parts of thickener, 1-10 parts of binder and 50-100 parts of deionized water.
2. The functional lithium battery separator paste according to claim 1, wherein the dispersant is one or a mixture of fatty acids ethylene oxide and polyethylene glycol in any ratio; the thickening agent is one or a mixture of carboxymethylcellulose sodium, polyacrylate and polyethylene oxide in any proportion; the binder is one or a mixture of acrylate and polyvinyl butyral in any proportion.
3. The functional lithium battery separator paste according to claim 1, which is prepared by a method comprising the steps of:
step 1: adding a dispersing agent into deionized water, and uniformly stirring to obtain a mixed solution;
step 2: adding PVDF powder into the mixed solution obtained in the step (1) and then uniformly stirring;
and step 3: adding the thickening agent and then uniformly stirring;
and 4, step 4: adding the binder and stirring uniformly;
and 5: adding the polystyrene butadiene emulsion, and uniformly dispersing to obtain the functional lithium battery diaphragm slurry.
4. A functional lithium battery separator comprising a base film and a coating layer formed by coating the functional lithium battery separator slurry of any one of claims 1 to 3 on one side or both sides of the base film.
5. The functional lithium battery separator according to claim 4, wherein the base film is one of a polypropylene-based film, a polyethylene-based film, and a non-woven fabric-based film.
6. The functional lithium battery separator according to claim 4, wherein the coating means is spin coating or micro gravure reverse roll coating.
7. The functional lithium battery separator as claimed in claim 6, wherein during the spin coating process, the vehicle speed is 35-60m/min, the rotor speed is 6500-.
8. The functional lithium battery separator as claimed in claim 6, wherein the speed of the micro-gravure reverse roll coating process is 35-60m/min, and the speed ratio of the coating roll is 100-130%.
9. The functional lithium battery separator according to claim 4, wherein the coating layer has a thickness of 0.5 to 5 μm.
10. A lithium battery comprising a positive electrode, a negative electrode, an electrolyte, and the functional lithium battery separator according to any one of claims 4 to 9.
Priority Applications (1)
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2019153822A1 (en) * | 2018-02-07 | 2019-08-15 | 沧州明珠塑料股份有限公司 | Adhesive polymer-coated lithium-ion battery separator and manufacturing method therefor |
| CN110707266A (en) * | 2019-09-23 | 2020-01-17 | 河北金力新能源科技股份有限公司 | PVDF (polyvinylidene fluoride) mixed coating slurry, preparation method thereof and diaphragm |
| CN110838567A (en) * | 2019-10-25 | 2020-02-25 | 河北金力新能源科技股份有限公司 | PVDF (polyvinylidene fluoride) diaphragm slurry, preparation method thereof, diaphragm prepared from PVDF diaphragm slurry and battery cell |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019153822A1 (en) * | 2018-02-07 | 2019-08-15 | 沧州明珠塑料股份有限公司 | Adhesive polymer-coated lithium-ion battery separator and manufacturing method therefor |
| CN110707266A (en) * | 2019-09-23 | 2020-01-17 | 河北金力新能源科技股份有限公司 | PVDF (polyvinylidene fluoride) mixed coating slurry, preparation method thereof and diaphragm |
| CN110838567A (en) * | 2019-10-25 | 2020-02-25 | 河北金力新能源科技股份有限公司 | PVDF (polyvinylidene fluoride) diaphragm slurry, preparation method thereof, diaphragm prepared from PVDF diaphragm slurry and battery cell |
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