CN105244465A - Production process of lithium ion microporous membrane - Google Patents
Production process of lithium ion microporous membrane Download PDFInfo
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- CN105244465A CN105244465A CN201510678733.5A CN201510678733A CN105244465A CN 105244465 A CN105244465 A CN 105244465A CN 201510678733 A CN201510678733 A CN 201510678733A CN 105244465 A CN105244465 A CN 105244465A
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- stretching
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- 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
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- 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
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- 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
- H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
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- 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)
- Laminated Bodies (AREA)
- Cell Separators (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Abstract
The invention discloses a production process of a lithium ion microporous membrane. The production process of the lithium ion microporous membrane is characterized by sequentially comprising the following steps of: a sheet forming step, wherein a polyethylene raw material and a polypropylene raw material form a melt in an extruder and flow out, and a curling device and an air cooler are arranged outside the extruder to enable the polyethylene raw material and the polypropylene raw material to form a polyethylene film and a polypropylene film; a thermal compounding step, namely arranging the polyethylene film and the polypropylene film in hot-pressing equipment for compounding, and then forming a composite film in cooling equipment; a heat treatment step, wherein hot air equipment is arranged to continuously blow hot air to the composite film in the heating furnace; and a stretching step of stretching the composite film by using stretching equipment.
Description
Technical Field
The invention relates to a production process of a lithium ion microporous membrane.
Background
The batteries commonly used in the world at present are: 4 kinds of disposable alkaline zinc-manganese batteries, rechargeable nickel batteries, lead-acid storage batteries, lithium ion batteries and the like. The lithium ion battery has become the main power source of various electronic products due to its advantages of high efficiency, safety, high working voltage, high energy density, long cycle life, no memory effect, no pollution and the like.
Although China is one of the most important lithium ion battery producing countries in the world, the quality of lithium ion battery products is at the middle and low end levels. The lithium ion microporous membrane is seriously dependent on import, and data shows that the amount of the lithium ion microporous membrane imported from China in the days, the America, the Korean countries and other countries in 2013 is 3.2 hundred million dollars. The research and development of lithium ion microporous membranes, particularly the industrialization aspect, are far behind the advanced level in the world in China.
The microporous membrane is an important component of the lithium ion battery, and the quality of the microporous membrane directly influences the characteristics of the battery, such as internal resistance, capacity, cycle performance and the like. The existing lithium ion microporous membrane is mostly a single-layer membrane, and the poor strength and air permeability of the microporous membrane cause the poor cycle performance and short service life of the existing lithium ion battery, so how to improve the performance of the microporous membrane is a technical problem which is urgently needed to be solved at present.
Disclosure of Invention
The invention aims to solve the technical problems and provides a production process of a lithium ion microporous membrane.
The invention is realized by the following technical scheme: the production process of the lithium ion microporous membrane sequentially comprises the following steps: a sheet forming step, wherein a polyethylene raw material and a polypropylene raw material form a melt in an extruder and flow out, and a curling device and an air cooler are arranged outside the extruder to enable the polyethylene raw material and the polypropylene raw material to form a polyethylene film and a polypropylene film; a thermal compounding step, namely arranging the polyethylene film and the polypropylene film in hot-pressing equipment for compounding, and then forming a composite film in cooling equipment; a heat treatment step, wherein hot air equipment is arranged to continuously blow hot air to the composite film in the heating furnace; and a stretching step of stretching the composite film by using stretching equipment.
Preferably, the extruder in the sheeting step is provided with an extrusion die at the melt outlet, the extrusion die being located adjacent to the crimping device, the distance between the extrusion die and the crimping device being < 7mm.
Preferably, the temperature of the extruder processing the polyethylene material in the sheeting step is from 200 to 210 ℃ and the temperature of the extruder processing the polypropylene material is from 210 to 230 ℃.
Preferably, the curling equipment, the hot pressing equipment, the cooling equipment and the stretching equipment are all provided with roll shafts rotating at constant speed and motors driving the roll shafts to rotate, and each roll shaft in the curling equipment, the hot pressing equipment, the cooling equipment and the stretching equipment is driven by at least one motor.
Preferably, when the roller shaft of the curling equipment is used for processing the polyethylene raw material, the linear speed is 35-40m/min, the temperature is 110-120 ℃, and the stretching ratio is more than 250 times; when a roll shaft of the curling equipment is used for processing the polypropylene raw material, the linear speed is 30-35m/min, the temperature is 85-95 ℃, and the stretching ratio is more than 200 times; the temperature of the air cooler is 20-30 ℃.
Preferably, the linear speed of the roller shafts of the hot-pressing equipment and the cooling equipment in the thermal compounding step is 5-6m/min; the temperature of the roller shaft of the hot-pressing equipment is 120-130 ℃, and the temperature of the roller shaft of the cooling equipment is 45-55 ℃.
Preferably, the duration of the hot air device continuously acting on the composite film in the heat treatment step is 5 to 7 hours, and the temperature is 120 to 130 ℃.
Preferably, the stretching step comprises a cold stretching step and a hot stretching step in sequence; the temperature of the roll shaft in the cold drawing step is 40-50 ℃, and the drawing ratio is 15-25%; the temperature of the roller shaft in the hot stretching step is 115-125 ℃, and the stretching ratio is 110-120%.
Preferably, the temperature is controlled to stay at 125-135 deg.C for 20-30 seconds after the hot stretching step is completed.
Preferably, the composite film is of a three-layer structure, the middle layer is a polyethylene film, and the upper layer and the lower layer are polypropylene films.
The beneficial effects are that: the invention describes a production process of a three-layer film compounded by a polyethylene film and a polypropylene film, compared with the prior art, the process increases the stretching ratio of the polyethylene film and the polypropylene film and the linear pressure of hot pressing of the composite film, and sets the linear speed of a roller shaft according to the requirements of different steps, thereby increasing the strength of a microporous film and enhancing the air permeability and balance. In the process, the polyethylene and polypropylene raw materials are both ultrahigh molecular weight raw materials, so that the influence of the change of the stretching temperature and the stretching ratio on the ultrahigh molecular weight raw materials is small in the stretching process.
Detailed Description
The production process of the lithium ion microporous membrane comprises a sheeting step, a thermal compounding step, a heat treatment step and a stretching step.
A step of sheeting: the polyethylene raw material and the polypropylene raw material form a melt in an extruder and flow out, and a curling device and an air cooler are arranged outside the extruder to enable the polyethylene raw material and the polypropylene raw material to form a polyethylene film and a polypropylene film. The extruder is provided with an extrusion die head at a melt outlet, the extrusion die head is tightly attached to a crimping device, the distance between the extrusion die head and the crimping device is less than 7mm, the extrusion die head is preferably a clothes-hanger-shaped vertically-arranged extrusion die head, the width of the extrusion die head is preferably 1000mm, the gap width is preferably 3mm, the temperature is preferably 200-210 ℃, the linear speed of a roller shaft of the crimping device is preferably 40m/min when processing a polyethylene raw material, the temperature is preferably 115 ℃, and the drawing ratio is more than 250 times; when a roll shaft of the curling equipment is used for processing a polypropylene raw material, the linear speed is preferably 32m/min, the temperature is preferably 90 ℃, and the stretching ratio is more than 200 times; the temperature of the air cooler is preferably 25 ℃. The thickness of the polyethylene film obtained in the sheeting step is 11 μm, and the elastic recovery rate is 29.6%; the polypropylene film obtained in the sheeting step had a thickness of 12 μm. The 100% elastic recovery of the polypropylene film after a heat treatment at 150 ℃ for 60 minutes was 88.2%. The purpose of the sheeting step is to arrange the molecular chains of the polyethylene material and the polypropylene material into a sheet crystal structure by high-rate stretching.
Thermal compounding: the polyethylene film and the polypropylene film are arranged in hot-pressing equipment for compounding, and then the composite film is formed in cooling equipment. The composite film is preferably of a three-layer structure, the middle layer is a polyethylene film, and the upper layer and the lower layer are polypropylene films. The linear speed of the roller shafts of the hot pressing equipment and the cooling equipment is preferably 5.4m/min; the temperature of the roll shaft of the hot-pressing device is preferably 125 ℃, and the temperature of the roll shaft of the cooling device is preferably 50 ℃. The thickness of the composite film obtained in the thermal compounding step was 34 μm, and the peel strength between the films of the composite film was 16g/15mm. The purpose of the thermal compounding step is to improve the physical properties of the three-layer film compounded by the polyethylene film and the polypropylene film.
A heat treatment step: and arranging hot air equipment to continuously blow hot air to the composite film in the heating furnace. The duration of the action of the hot air device on the composite film is preferably 6 hours, and the temperature is preferably 125 ℃. The purpose of the heat treatment step is to eliminate the internal stress of the composite film, correct the defects formed in the heat compounding step and improve the adhesion between the films.
A stretching step: and stretching the composite film by using stretching equipment. The stretching step sequentially comprises a cold stretching step and a hot stretching step; the temperature of the roller shaft in the cold stretching step is preferably 45 ℃, and the stretching ratio is preferably 20%; the temperature of the roll in the hot stretching step is preferably 120 c, and the stretching ratio is preferably 115%. The temperature is preferably controlled to a dwell at 130 c for 25 seconds after the hot stretching step is completed. The composite film obtained in the stretching step had a thermal relaxation of 16.7%. The purpose of the cold stretching step is to break the platelet structure formed in the sheeting step by low temperature stretching, and to cause micro cracks; the purpose of the hot-stretching step is to continue to enlarge the fracture and thereby form the micropores.
The composite film produced by the lithium ion microporous film production process meets the following technical indexes: the thickness is 15-40 μm, the porosity of micropores is 38%, the air permeability is 200-1200s/100ml, the heat shrinkage is 1.05h/90 deg.C, and the tensile strength is more than or equal to 1500Kgf/cm 2 The puncture strength was 4N.
The production process of the lithium ion microporous membrane overcomes the following technical difficulties: the composite material of polyethylene raw material and polypropylene raw material is selected to obtain an ideal lamellar crystal structure under high-rate stretching; the composite material can not generate cracks because the polypropylene film is easy to form spherulites at overhigh temperature, and can not generate fine wrinkles because the surface friction force of the polypropylene film is large at overlow temperature; the speed of the thermal compounding step is increased, and the yield is improved; the produced composite film has low thermal relaxation and good air permeability.
The above embodiments are only for illustrating the technical solutions of the present invention and are not limited thereto, and any modification or equivalent replacement without departing from the spirit and scope of the present invention should be covered within the technical solutions of the present invention.
Claims (10)
1. The production process of the lithium ion microporous membrane is characterized by sequentially comprising the following steps of: a sheet forming step, wherein a polyethylene raw material and a polypropylene raw material form a melt in an extruder and flow out, and a curling device and an air cooler are arranged outside the extruder to enable the polyethylene raw material and the polypropylene raw material to form a polyethylene film and a polypropylene film; a thermal compounding step, namely arranging the polyethylene film and the polypropylene film in hot-pressing equipment for compounding, and then forming a composite film in cooling equipment; a heat treatment step, wherein hot air equipment is arranged to continuously blow hot air to the composite film in the heating furnace; and a stretching step of stretching the composite film by using stretching equipment.
2. The process for producing a lithium ion microporous membrane according to claim 1, wherein the extruder in the sheeting step is provided with an extrusion die at a melt outlet, the extrusion die is closely attached to a crimping device, and the distance between the extrusion die and the crimping device is less than 7mm.
3. The lithium ion microporous membrane production process according to claim 1, wherein the temperature of the extruder for processing the polyethylene raw material in the sheeting step is 200-210 ℃, and the temperature of the extruder for processing the polypropylene raw material is 210-230 ℃.
4. The lithium ion microporous membrane production process according to claim 1, wherein the curling device, the hot pressing device, the cooling device and the stretching device are all provided with a roll shaft rotating at a constant speed and a motor driving the roll shaft to rotate, and each roll shaft in the curling device, the hot pressing device, the cooling device and the stretching device is driven by at least one motor.
5. The lithium ion microporous membrane production process according to claim 4, wherein the linear speed of the roller of the curling equipment for processing the polyethylene raw material is 35-40m/min, the temperature is 110-120 ℃, and the stretching ratio is more than 250 times; when the roller shaft of the curling equipment is used for processing the polypropylene raw material, the linear speed is 30-35m/min, the temperature is 85-95 ℃, and the stretching ratio is more than 200 times; the temperature of the air cooler is 20-30 ℃.
6. The production process of the lithium ion microporous membrane according to claim 4, wherein the linear speed of the roll shafts of the hot-pressing device and the cooling device in the thermal compounding step is 5 to 6m/min; the temperature of the roller shaft of the hot-pressing equipment is 120-130 ℃, and the temperature of the roller shaft of the cooling equipment is 45-55 ℃.
7. The process for producing a lithium ion microporous membrane according to claim 1, wherein the duration of the heat-treatment step in which the hot air device continuously acts on the composite membrane is 5 to 7 hours at a temperature of 120 to 130 ℃.
8. The lithium ion microporous membrane production process according to claim 4, wherein the stretching step comprises a cold stretching step and a hot stretching step in this order; the temperature of the roll shaft in the cold drawing step is 40-50 ℃, and the drawing ratio is 15-25%; the temperature of the roller shaft in the hot stretching step is 115-125 ℃, and the stretching ratio is 110-120%.
9. The lithium ion microporous membrane production process according to claim 8, wherein the temperature is controlled to stay at 125-135 ℃ for 20-30 seconds after the hot stretching step is completed.
10. The production process of the lithium ion microporous membrane according to claim 1, wherein the composite membrane is a three-layer structure, the middle layer is a polyethylene membrane, and the upper layer and the lower layer are polypropylene membranes.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201510678733.5A CN105244465B (en) | 2015-10-20 | 2015-10-20 | Production process of lithium ion microporous membrane |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201510678733.5A CN105244465B (en) | 2015-10-20 | 2015-10-20 | Production process of lithium ion microporous membrane |
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| CN105244465A true CN105244465A (en) | 2016-01-13 |
| CN105244465B CN105244465B (en) | 2017-10-24 |
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| CN201510678733.5A Active CN105244465B (en) | 2015-10-20 | 2015-10-20 | Production process of lithium ion microporous membrane |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106981608A (en) * | 2017-05-08 | 2017-07-25 | 深圳市星源材质科技股份有限公司 | A kind of preparation method of lithium ion battery multilayer microporous film |
| CN110406136A (en) * | 2019-06-26 | 2019-11-05 | 佛山市盈博莱科技股份有限公司 | A kind of preparation method of Multi-layer composite lithium ion battery separator |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20010045683A1 (en) * | 1997-10-09 | 2001-11-29 | Asahi Kogaku Kogyo Kabushiki Kaisha | Producing apparatus of film with through-holes |
| CN102241142A (en) * | 2011-05-16 | 2011-11-16 | 中材科技股份有限公司 | Method for producing lithium battery diaphragm and transverse stretcher |
| CN104022249A (en) * | 2014-06-26 | 2014-09-03 | 佛山市盈博莱科技有限公司 | Three-layer lithium battery diaphragm and preparation method thereof |
-
2015
- 2015-10-20 CN CN201510678733.5A patent/CN105244465B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20010045683A1 (en) * | 1997-10-09 | 2001-11-29 | Asahi Kogaku Kogyo Kabushiki Kaisha | Producing apparatus of film with through-holes |
| CN102241142A (en) * | 2011-05-16 | 2011-11-16 | 中材科技股份有限公司 | Method for producing lithium battery diaphragm and transverse stretcher |
| CN104022249A (en) * | 2014-06-26 | 2014-09-03 | 佛山市盈博莱科技有限公司 | Three-layer lithium battery diaphragm and preparation method thereof |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106981608A (en) * | 2017-05-08 | 2017-07-25 | 深圳市星源材质科技股份有限公司 | A kind of preparation method of lithium ion battery multilayer microporous film |
| CN106981608B (en) * | 2017-05-08 | 2021-06-11 | 深圳市星源材质科技股份有限公司 | Preparation method of multilayer microporous membrane for lithium ion battery |
| CN110406136A (en) * | 2019-06-26 | 2019-11-05 | 佛山市盈博莱科技股份有限公司 | A kind of preparation method of Multi-layer composite lithium ion battery separator |
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| CN105244465B (en) | 2017-10-24 |
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Denomination of invention: Production process of lithium ion microporous membrane Effective date of registration: 20210114 Granted publication date: 20171024 Pledgee: China Co. truction Bank Corp Jiangmen branch Pledgor: JIANGMEN PENGJIANG HUALONG PACKING MATERIAL Co.,Ltd. Registration number: Y2021440000010 |
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