CN110828752A - Preparation method of low-stress lithium ion battery ceramic coating diaphragm - Google Patents
Preparation method of low-stress lithium ion battery ceramic coating diaphragm Download PDFInfo
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- 238000005524 ceramic coating Methods 0.000 title claims abstract description 35
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 28
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 28
- 238000002360 preparation method Methods 0.000 title claims abstract description 18
- 239000011247 coating layer Substances 0.000 claims abstract description 16
- 239000011248 coating agent Substances 0.000 claims abstract description 11
- 238000000576 coating method Methods 0.000 claims abstract description 11
- 238000000034 method Methods 0.000 claims description 26
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 24
- 239000003795 chemical substances by application Substances 0.000 claims description 20
- 229920000098 polyolefin Polymers 0.000 claims description 19
- 239000000126 substance Substances 0.000 claims description 18
- 239000000919 ceramic Substances 0.000 claims description 16
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 15
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims description 12
- 229910052757 nitrogen Inorganic materials 0.000 claims description 12
- 239000004005 microsphere Substances 0.000 claims description 11
- 239000000853 adhesive Substances 0.000 claims description 10
- 230000001070 adhesive effect Effects 0.000 claims description 10
- 239000002270 dispersing agent Substances 0.000 claims description 10
- 239000002994 raw material Substances 0.000 claims description 10
- 239000000080 wetting agent Substances 0.000 claims description 10
- 239000000047 product Substances 0.000 claims description 8
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 claims description 7
- 239000001099 ammonium carbonate Substances 0.000 claims description 7
- 239000012528 membrane Substances 0.000 claims description 7
- 239000011265 semifinished product Substances 0.000 claims description 7
- 239000002033 PVDF binder Substances 0.000 claims description 6
- 238000002844 melting Methods 0.000 claims description 6
- 230000008018 melting Effects 0.000 claims description 6
- 229920003229 poly(methyl methacrylate) Polymers 0.000 claims description 6
- -1 polyethylene Polymers 0.000 claims description 6
- 229920000642 polymer Polymers 0.000 claims description 6
- 239000004926 polymethyl methacrylate Substances 0.000 claims description 6
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 6
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 claims description 5
- XSTXAVWGXDQKEL-UHFFFAOYSA-N Trichloroethylene Chemical group ClC=C(Cl)Cl XSTXAVWGXDQKEL-UHFFFAOYSA-N 0.000 claims description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 5
- 229940072049 amyl acetate Drugs 0.000 claims description 5
- PGMYKACGEOXYJE-UHFFFAOYSA-N anhydrous amyl acetate Natural products CCCCCOC(C)=O PGMYKACGEOXYJE-UHFFFAOYSA-N 0.000 claims description 5
- 238000005266 casting Methods 0.000 claims description 5
- 229960001701 chloroform Drugs 0.000 claims description 5
- 238000013329 compounding Methods 0.000 claims description 5
- 238000001816 cooling Methods 0.000 claims description 5
- 239000008367 deionised water Substances 0.000 claims description 5
- 229910021641 deionized water Inorganic materials 0.000 claims description 5
- 238000001035 drying Methods 0.000 claims description 5
- 238000000605 extraction Methods 0.000 claims description 5
- MNWFXJYAOYHMED-UHFFFAOYSA-M heptanoate Chemical compound CCCCCCC([O-])=O MNWFXJYAOYHMED-UHFFFAOYSA-M 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 239000003960 organic solvent Substances 0.000 claims description 5
- 229920001495 poly(sodium acrylate) polymer Polymers 0.000 claims description 5
- 238000007493 shaping process Methods 0.000 claims description 5
- NNMHYFLPFNGQFZ-UHFFFAOYSA-M sodium polyacrylate Chemical group [Na+].[O-]C(=O)C=C NNMHYFLPFNGQFZ-UHFFFAOYSA-M 0.000 claims description 5
- 239000002904 solvent Substances 0.000 claims description 5
- UBOXGVDOUJQMTN-UHFFFAOYSA-N trichloroethylene Natural products ClCC(Cl)Cl UBOXGVDOUJQMTN-UHFFFAOYSA-N 0.000 claims description 5
- 229960002415 trichloroethylene Drugs 0.000 claims description 5
- 238000009966 trimming Methods 0.000 claims description 5
- 238000005406 washing Methods 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 229920002845 Poly(methacrylic acid) Polymers 0.000 claims description 4
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical compound [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 claims description 4
- 229920002125 Sokalan® Polymers 0.000 claims description 4
- 235000012501 ammonium carbonate Nutrition 0.000 claims description 4
- 235000006408 oxalic acid Nutrition 0.000 claims description 4
- 229920005569 poly(vinylidene fluoride-co-hexafluoropropylene) Polymers 0.000 claims description 4
- 229940051841 polyoxyethylene ether Drugs 0.000 claims description 4
- 229920000056 polyoxyethylene ether Polymers 0.000 claims description 4
- 238000005507 spraying Methods 0.000 claims description 4
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 claims description 3
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 claims description 3
- 229920000459 Nitrile rubber Polymers 0.000 claims description 3
- 239000004698 Polyethylene Substances 0.000 claims description 3
- 239000002202 Polyethylene glycol Substances 0.000 claims description 3
- 239000004642 Polyimide Substances 0.000 claims description 3
- 239000004743 Polypropylene Substances 0.000 claims description 3
- 239000002174 Styrene-butadiene Substances 0.000 claims description 3
- 235000012538 ammonium bicarbonate Nutrition 0.000 claims description 3
- NTXGQCSETZTARF-UHFFFAOYSA-N buta-1,3-diene;prop-2-enenitrile Chemical compound C=CC=C.C=CC#N NTXGQCSETZTARF-UHFFFAOYSA-N 0.000 claims description 3
- MTAZNLWOLGHBHU-UHFFFAOYSA-N butadiene-styrene rubber Chemical compound C=CC=C.C=CC1=CC=CC=C1 MTAZNLWOLGHBHU-UHFFFAOYSA-N 0.000 claims description 3
- 229920000058 polyacrylate Polymers 0.000 claims description 3
- 229920002239 polyacrylonitrile Polymers 0.000 claims description 3
- 229920000573 polyethylene Polymers 0.000 claims description 3
- 229920001223 polyethylene glycol Polymers 0.000 claims description 3
- 229920001721 polyimide Polymers 0.000 claims description 3
- 229920001155 polypropylene Polymers 0.000 claims description 3
- 239000011115 styrene butadiene Substances 0.000 claims description 3
- 229920003048 styrene butadiene rubber Polymers 0.000 claims description 3
- 238000005096 rolling process Methods 0.000 claims 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 abstract description 4
- 229910052744 lithium Inorganic materials 0.000 abstract description 4
- 239000000463 material Substances 0.000 description 5
- 230000007547 defect Effects 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 239000004584 polyacrylic acid Substances 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 239000011256 inorganic filler Substances 0.000 description 1
- 229910003475 inorganic filler Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 238000007761 roller coating Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000009736 wetting 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
- 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
- H01M50/431—Inorganic 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
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Cell Separators (AREA)
Abstract
The invention discloses a preparation method of a low-stress lithium ion battery ceramic coating diaphragm, which belongs to the technical field of lithium ion battery preparation. And coating a ceramic coating layer on the base film to obtain the low-stress lithium ion battery ceramic coating diaphragm. The preparation method of the invention can improve the performance of the lithium battery.
Description
Technical Field
The invention belongs to the technical field of lithium ion battery preparation, and relates to a preparation method of a low-stress lithium ion battery ceramic coating diaphragm.
Background
The separator has a crucial influence on the performance of a practical battery, and must have good chemical, electrochemical, thermal stability and maintain high wettability to the electrolyte during repeated charging and discharging. One of the key factors affecting the safety of the lithium ion power battery is the safety of the diaphragm. The conventional polyolefin diaphragm has the problems of low melting point, poor mechanical property and the like, and due to the hydrophobic property of the polyolefin diaphragm, the polyolefin diaphragm has poor wetting and storage properties on electrolyte, increases impedance, and limits the high-rate charge and discharge performance of a lithium battery and the cycle performance of the lithium battery.
At present, in the prior art, a preparation method of a low-stress lithium ion battery ceramic coating diaphragm does not exist.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a preparation method of a low-stress lithium ion battery ceramic coating diaphragm, which can improve the performance of a lithium battery.
The specific technical scheme is as follows:
a preparation method of a low-stress lithium ion battery ceramic coating diaphragm comprises the following steps:
step 1, compounding a polyolefin raw material and a pore-forming agent;
step 2, after high-temperature melting casting and cooling film forming, stretching longitudinally and transversely, and then carrying out low-temperature stress relief treatment on the biaxially stretched film;
step 3, removing the pore-forming agent through conventional chemical extraction, washing with deionized water, and drying at low temperature;
step 4, trimming the melted and stretched polyolefin structure of the extracted diaphragm semi-finished product through a chemical stress process;
step 5, performing secondary low-temperature shaping treatment to obtain a low-stress base film;
and 6, coating a ceramic coating layer on the base film obtained in the step 5 to obtain the low-stress lithium ion battery ceramic coating diaphragm.
Further, in step 1, the polyolefin raw material is one or a mixture of two or more of polyethylene, polypropylene and polyimide.
Further, in step 2, the low-temperature stress relief treatment is as follows: under the environment of nitrogen protection with the pressure of 0.5-1.0MPa (the pressure is kept sufficient so that the temperature is always kept in the required range) and the circulation rate of 600-800cc/min (the chemical property of the nitrogen is very inactive, the reaction is only carried out under the conditions of high temperature and high pressure or discharge, and the nitrogen is non-toxic and pollution-free), and at the temperature of 75-125 ℃ (the tensile strength of the diaphragm is kept neither too high nor too low), the tensile force of 1.5-2.0N is uniformly applied to the longitudinal direction and the transverse direction of the semi-finished product of the diaphragm, the pulling speed is 1.0-3.0min, and the processing time is 45-60 min. Low-temperature stress relief principle: during other processes, the membrane may develop internal stresses. In most cases, a portion of the residual stress will remain inside the membrane after the process is completed. Residual stresses can cause the diaphragm to crack, deform or dimensionally change, thereby affecting the quality of the diaphragm.
When the low-temperature stress relief is carried out, the diaphragm can release residual stress under the action of a certain temperature through internal local plastic deformation (when the stress exceeds the yield strength of the material at the temperature) or local relaxation (when the stress is less than the yield strength of the material at the temperature). During destressing, the material is generally heated slowly to a lower temperature, and after a certain period of time, the material is cooled slowly to prevent new residual stress from being generated.
Further, in step 4, the chemical destressing process is as follows: 30-50ml/L of organic solvent such as toluene, amyl acetate, trichloroethylene, trichloromethane and the like, wherein the temperature of the solvent is 80-100 ℃.
Further, in step 5, the secondary low-temperature stress relief process is as follows: under the environment of nitrogen protection with the pressure of 0.5-1.0MPa and the circulation rate of 1000-1500cc/min, under the temperature of 100-150 ℃, the longitudinal and transverse tension of 1.0-1.5N is uniformly applied to the semi-finished diaphragm product, the pulling speed is 1.0-5.0min, and the processing time is 30-60 min.
Further, in step 6, the preparation method of the ceramic coating layer comprises the following steps: 30-60 parts of ceramic hollow microspheres, 1-2.5 parts of wetting agent, 0.2-1 part of dispersing agent, 10-25 parts of adhesive and 0.5-2 parts of pore-forming agent.
Furthermore, the ceramic hollow microspheres are mainly alumina, and the wetting agent is fatty alcohol-polyoxyethylene ether and sodium dodecyl sulfate; the dispersant is sodium polyacrylate and polyethylene glycol; the adhesive is any one or more of polyvinylidene fluoride (PVDF), styrene-butadiene polymer, butadiene-acrylonitrile polymer, polyvinylidene fluoride-hexafluoropropylene, polyacrylic acid-styrene, polyacrylic acid (PAA), polymethacrylic acid, polyacrylate, polymethyl methacrylate (PMMA) and polyacrylonitrile; the pore-forming agent is one or more of ammonium bicarbonate, oxalic acid, ammonium carbonate and ammonium nitrate.
Further, in step 6, the ceramic coating layer is coated on the base film subjected to the stress treatment by adopting a spraying and roll coating mode.
Compared with the prior art, the invention has the beneficial effects that:
1. the low-stress base membrane material is prepared by adopting a process mode of combining chemical stress relief treatment and physical stress relief treatment, so that the performance defect that the stress of the polyolefin diaphragm is concentrated on the market is effectively reduced, the heat shrinkage performance of the diaphragm is improved, and the safety performance of the lithium ion battery is improved.
2. The hollow ceramic microspheres are used as inorganic filler, so that the bulk density of the coating is reduced, various performances of the diaphragm are improved, and the high-temperature resistance of the diaphragm is improved.
Detailed Description
The technical solution of the present invention will be described in further detail with reference to specific examples.
Example 1
A preparation method of a low-stress lithium ion battery ceramic coating diaphragm comprises the following steps:
step 1, compounding a polyolefin raw material and a pore-forming agent;
step 2, after high-temperature melting casting and cooling film forming, stretching longitudinally and transversely, and then carrying out low-temperature stress relief treatment on the biaxially stretched film;
step 3, removing the pore-forming agent through conventional chemical extraction, washing with deionized water, and drying at low temperature;
step 4, trimming the melted and stretched polyolefin structure of the extracted diaphragm semi-finished product through a chemical stress process;
step 5, performing secondary low-temperature shaping treatment to obtain a low-stress base film;
and 6, coating a ceramic coating layer on the base film obtained in the step 5 to obtain the low-stress lithium ion battery ceramic coating diaphragm.
In step 1, the polyolefin raw material is polyethylene.
In step 2, the low-temperature stress relief treatment comprises the following steps: the semi-finished diaphragm product is uniformly applied with a tensile force of 1.5N in the longitudinal direction and the transverse direction at a pulling speed of 1.0min and a processing time of 45min at a temperature of 75 ℃ in an environment with a pressure of 0.5MPa and a circulation rate of 600cc/min under the protection of nitrogen.
In step 4, the chemical destressing process comprises the following steps: 30ml/L of organic solvent such as toluene, amyl acetate, trichloroethylene, trichloromethane and the like, wherein the temperature of the solvent is 80 ℃.
In step 5, the secondary low-temperature stress relief process comprises the following steps: uniformly applying a tensile force of 1.0N at a pulling speed of 1.0min to the longitudinal direction and the transverse direction of the semi-finished diaphragm product at a temperature of 100 ℃ in an environment with a pressure of 0.5MPa and a circulation rate of 1000cc/min under the protection of nitrogen, wherein the treatment time is 30 min.
In step 6, the preparation method of the ceramic coating layer comprises the following steps: 30 parts of ceramic hollow microspheres, 1 part of wetting agent, 0.2 part of dispersing agent, 10 parts of adhesive and 0.5 part of pore-forming agent are uniformly stirred.
The ceramic hollow microspheres are mainly alumina, and the wetting agent is fatty alcohol-polyoxyethylene ether; the dispersant is sodium polyacrylate alcohol; the adhesive is a mixture of polyvinylidene fluoride (PVDF), styrene-butadiene polymer, butadiene-acrylonitrile polymer and polyvinylidene fluoride-hexafluoropropylene; the pore-forming agent is ammonium bicarbonate or oxalic acid.
And 6, coating the ceramic coating layer on the base film subjected to the stress treatment in a spraying mode.
Example 2
A preparation method of a low-stress lithium ion battery ceramic coating diaphragm comprises the following steps:
step 1, compounding a polyolefin raw material and a pore-forming agent;
step 2, after high-temperature melting casting and cooling film forming, stretching longitudinally and transversely, and then carrying out low-temperature stress relief treatment on the biaxially stretched film;
step 3, removing the pore-forming agent through conventional chemical extraction, washing with deionized water, and drying at low temperature;
step 4, trimming the melted and stretched polyolefin structure of the extracted diaphragm semi-finished product through a chemical stress process;
step 5, performing secondary low-temperature shaping treatment to obtain a low-stress base film;
and 6, coating a ceramic coating layer on the base film obtained in the step 5 to obtain the low-stress lithium ion battery ceramic coating diaphragm.
In step 1, the polyolefin raw material is polypropylene.
In step 2, the low-temperature stress relief treatment comprises the following steps: the semi-finished diaphragm product is uniformly applied with a tensile force of 1.8N in the longitudinal direction and the transverse direction at a pulling speed of 2.0min and a processing time of 50min at a temperature of 100 ℃ in an environment with a pressure of 0.8MPa and a circulation rate of 700cc/min under the protection of nitrogen.
In step 4, the chemical destressing process comprises the following steps: 40ml/L organic solvent such as toluene, amyl acetate, trichloroethylene, trichloromethane and the like, wherein the temperature of the solvent is 90 ℃.
In step 5, the secondary low-temperature stress relief process comprises the following steps: the semi-finished diaphragm product was uniformly applied with a tensile force of 1.3N in the longitudinal and transverse directions at a pulling rate of 3.0min for a treatment time of 45min at a temperature of 130 ℃ in an atmosphere of nitrogen protection with a pressure of 0.8MPa and a circulation rate of 1250 cc/min.
In step 6, the preparation method of the ceramic coating layer comprises the following steps: 45 parts of ceramic hollow microspheres, 2 parts of wetting agent, 0.6 part of dispersing agent, 18 parts of adhesive and 1.2 parts of pore-forming agent are uniformly stirred.
The ceramic hollow microspheres are mainly alumina, and the wetting agent is sodium dodecyl sulfate; the dispersant is sodium polyacrylate; the adhesive is a mixture of polyvinylidene fluoride-hexafluoropropylene, polyacrylic acid-styrene, polyacrylic acid PAA and polymethacrylic acid; the pore-forming agent is oxalic acid and ammonium carbonate.
And 6, coating the ceramic coating layer on the base film subjected to the stress treatment in a roller coating mode.
Example 3
A preparation method of a low-stress lithium ion battery ceramic coating diaphragm comprises the following steps:
step 1, compounding a polyolefin raw material and a pore-forming agent;
step 2, after high-temperature melting casting and cooling film forming, stretching longitudinally and transversely, and then carrying out low-temperature stress relief treatment on the biaxially stretched film;
step 3, removing the pore-forming agent through conventional chemical extraction, washing with deionized water, and drying at low temperature;
step 4, trimming the melted and stretched polyolefin structure of the extracted diaphragm semi-finished product through a chemical stress process;
step 5, performing secondary low-temperature shaping treatment to obtain a low-stress base film;
and 6, coating a ceramic coating layer on the base film obtained in the step 5 to obtain the low-stress lithium ion battery ceramic coating diaphragm.
In step 1, the polyolefin raw material is polyimide.
In step 2, the low-temperature stress relief treatment comprises the following steps: uniformly applying 2.0N tensile force with the pulling speed of 3.0min to the longitudinal direction and the transverse direction of the semi-finished diaphragm product at the temperature of 125 ℃ in an environment with the pressure of 1.0MPa and the circulation rate of 800cc/min under the protection of nitrogen, wherein the treatment time is 60 min.
In step 4, the chemical destressing process comprises the following steps: 50ml/L of organic solvent such as toluene, amyl acetate, trichloroethylene, trichloromethane and the like, wherein the temperature of the solvent is 100 ℃.
In step 5, the secondary low-temperature stress relief process comprises the following steps: the semi-finished diaphragm product is uniformly applied with a tensile force of 1.5N in the longitudinal direction and the transverse direction at a pulling speed of 5.0min and a processing time of 60min at a temperature of 150 ℃ in an environment with a pressure of 1.0MPa and a circulation rate of 1500cc/min under the protection of nitrogen.
In step 6, the preparation method of the ceramic coating layer comprises the following steps: 60 parts of ceramic hollow microspheres, 2.5 parts of wetting agent, 1 part of dispersing agent, 25 parts of adhesive and 2 parts of pore-forming agent are uniformly stirred.
The ceramic hollow microspheres are mainly alumina, and the wetting agent is fatty alcohol-polyoxyethylene ether and sodium dodecyl sulfate; the dispersant is sodium polyacrylate and polyethylene glycol; the adhesive is a mixture of polymethacrylic acid, polyacrylate, polymethyl methacrylate (PMMA) and polyacrylonitrile; the pore-forming agent is ammonium carbonate or ammonium nitrate.
And 6, coating the ceramic coating layer on the base film subjected to the stress treatment in a spraying mode.
The above description is only a preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, and any simple modifications or equivalent substitutions of the technical solutions that can be obviously obtained by those skilled in the art within the technical scope of the present invention are within the scope of the present invention.
Claims (8)
1. A preparation method of a low-stress lithium ion battery ceramic coating diaphragm is characterized by comprising the following steps:
step 1, compounding a polyolefin raw material and a pore-forming agent;
step 2, after high-temperature melting casting and cooling film forming, stretching longitudinally and transversely, and then carrying out low-temperature stress relief treatment on the biaxially stretched film;
step 3, removing the pore-forming agent through conventional chemical extraction, washing with deionized water, and drying at low temperature;
step 4, trimming the melted and stretched polyolefin structure of the extracted diaphragm semi-finished product through a chemical stress process;
step 5, performing secondary low-temperature shaping treatment to obtain a low-stress base film;
and 6, coating a ceramic coating layer on the base film obtained in the step 5 to obtain the low-stress lithium ion battery ceramic coating diaphragm.
2. The method for preparing the ceramic-coated separator for the low-stress lithium ion battery according to claim 1, wherein in the step 1, the polyolefin raw material is one or a mixture of two or more of polyethylene, polypropylene and polyimide.
3. The method for preparing the ceramic coated membrane of the low-stress lithium ion battery according to claim 1, wherein in the step 2, the low-temperature stress removal treatment comprises the following steps: uniformly applying 1.5-2.0N of tensile force with the pulling speed of 1.0-3.0min to the longitudinal direction and the transverse direction of the diaphragm semi-finished product at the temperature of 75-125 ℃ in the environment with the pressure of 0.5-1.0MPa and the circulation rate of 800cc/min under the protection of nitrogen, wherein the treatment time is 45-60 min.
4. The method for preparing the low-stress lithium ion battery ceramic coating membrane according to claim 1, wherein in the step 4, the chemical stress removal process comprises the following steps: toluene, amyl acetate, trichloroethylene and trichloromethane organic solvents with the concentration of 30-50ml/L, wherein the temperature of the solvents is 80-100 ℃.
5. The method for preparing the ceramic coated membrane of the low-stress lithium ion battery according to claim 1, wherein in the step 5, the secondary low-temperature stress relief process comprises the following steps: under the environment of nitrogen protection with the pressure of 0.5-1.0MPa and the circulation rate of 1000-1500cc/min, under the temperature of 100-150 ℃, the longitudinal and transverse tension of 1.0-1.5N is uniformly applied to the semi-finished diaphragm product, the pulling speed is 1.0-5.0min, and the processing time is 30-60 min.
6. The method for preparing the ceramic coating diaphragm of the low-stress lithium ion battery according to claim 1, wherein in the step 6, the method for preparing the ceramic coating layer comprises the following steps: 30-60 parts of ceramic hollow microspheres, 1-2.5 parts of wetting agent, 0.2-1 part of dispersing agent, 10-25 parts of adhesive and 0.5-2 parts of pore-forming agent.
7. The method for preparing the ceramic coated membrane of the low-stress lithium ion battery according to claim 6, wherein the ceramic hollow microspheres are mainly alumina, and the wetting agent is fatty alcohol-polyoxyethylene ether or sodium dodecyl sulfate; the dispersant is sodium polyacrylate and polyethylene glycol; the adhesive is any one or more of polyvinylidene fluoride (PVDF), styrene-butadiene polymer, butadiene-acrylonitrile polymer, polyvinylidene fluoride-hexafluoropropylene, polyacrylic acid-styrene, polyacrylic acid (PAA), polymethacrylic acid, polyacrylate, polymethyl methacrylate (PMMA) and polyacrylonitrile; the pore-forming agent is one or more of ammonium bicarbonate, oxalic acid, ammonium carbonate and ammonium nitrate.
8. The method for preparing the ceramic coated separator of the low-stress lithium ion battery according to claim 1, wherein in the step 6, the ceramic coating layer is coated on the base film subjected to the stress treatment by adopting a spraying and rolling way.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911125540.1A CN110828752A (en) | 2019-11-18 | 2019-11-18 | Preparation method of low-stress lithium ion battery ceramic coating diaphragm |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201911125540.1A CN110828752A (en) | 2019-11-18 | 2019-11-18 | Preparation method of low-stress lithium ion battery ceramic coating diaphragm |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111916630A (en) * | 2020-07-24 | 2020-11-10 | 蜂巢能源科技有限公司 | A composite separator and its preparation method and battery |
| CN112467308A (en) * | 2020-10-27 | 2021-03-09 | 惠州锂威新能源科技有限公司 | Diaphragm, preparation method thereof and lithium ion battery |
| CN112981723A (en) * | 2021-01-26 | 2021-06-18 | 无锡优佳无纺科技有限公司 | Preparation method of porous polypropylene non-woven fabric |
| CN114914627A (en) * | 2022-06-15 | 2022-08-16 | 惠州锂威新能源科技有限公司 | Oily diaphragm, preparation method thereof and lithium ion battery |
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| CN108649168A (en) * | 2018-04-27 | 2018-10-12 | 中材锂膜有限公司 | A kind of preparation method of cenosphere ceramic coating membrane |
| CN110429225A (en) * | 2019-06-26 | 2019-11-08 | 高芳 | A kind of preparation method of lithium ion battery ceramic coating membrane |
| CN110444715A (en) * | 2019-06-26 | 2019-11-12 | 高芳 | A kind of low stress lithium ion battery separator and preparation method thereof |
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| CN108649168A (en) * | 2018-04-27 | 2018-10-12 | 中材锂膜有限公司 | A kind of preparation method of cenosphere ceramic coating membrane |
| CN110429225A (en) * | 2019-06-26 | 2019-11-08 | 高芳 | A kind of preparation method of lithium ion battery ceramic coating membrane |
| CN110444715A (en) * | 2019-06-26 | 2019-11-12 | 高芳 | A kind of low stress lithium ion battery separator and preparation method thereof |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111916630A (en) * | 2020-07-24 | 2020-11-10 | 蜂巢能源科技有限公司 | A composite separator and its preparation method and battery |
| CN111916630B (en) * | 2020-07-24 | 2022-04-12 | 蜂巢能源科技有限公司 | A composite separator and its preparation method and battery |
| CN112467308A (en) * | 2020-10-27 | 2021-03-09 | 惠州锂威新能源科技有限公司 | Diaphragm, preparation method thereof and lithium ion battery |
| CN112467308B (en) * | 2020-10-27 | 2023-09-05 | 惠州锂威新能源科技有限公司 | Diaphragm, preparation method thereof and lithium ion battery |
| CN112981723A (en) * | 2021-01-26 | 2021-06-18 | 无锡优佳无纺科技有限公司 | Preparation method of porous polypropylene non-woven fabric |
| CN114914627A (en) * | 2022-06-15 | 2022-08-16 | 惠州锂威新能源科技有限公司 | Oily diaphragm, preparation method thereof and lithium ion battery |
| CN114914627B (en) * | 2022-06-15 | 2023-06-20 | 惠州锂威新能源科技有限公司 | Oily diaphragm, preparation method thereof and lithium ion battery |
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