CN115534468A - Current collector composite film and film making process thereof - Google Patents
Current collector composite film and film making process thereof Download PDFInfo
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- CN115534468A CN115534468A CN202210969951.4A CN202210969951A CN115534468A CN 115534468 A CN115534468 A CN 115534468A CN 202210969951 A CN202210969951 A CN 202210969951A CN 115534468 A CN115534468 A CN 115534468A
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- 239000002131 composite material Substances 0.000 title claims abstract description 63
- 238000000034 method Methods 0.000 title claims abstract description 46
- 230000008569 process Effects 0.000 title claims abstract description 40
- 239000002344 surface layer Substances 0.000 claims abstract description 55
- 238000001125 extrusion Methods 0.000 claims abstract description 42
- 239000010410 layer Substances 0.000 claims abstract description 39
- 239000000463 material Substances 0.000 claims abstract description 37
- 229920000139 polyethylene terephthalate Polymers 0.000 claims abstract description 35
- 239000005020 polyethylene terephthalate Substances 0.000 claims abstract description 35
- 238000007493 shaping process Methods 0.000 claims abstract description 31
- 238000004519 manufacturing process Methods 0.000 claims abstract description 27
- 238000001816 cooling Methods 0.000 claims abstract description 25
- -1 polyethylene terephthalate Polymers 0.000 claims abstract description 22
- 239000012792 core layer Substances 0.000 claims abstract description 16
- 239000000155 melt Substances 0.000 claims abstract description 15
- 239000002202 Polyethylene glycol Substances 0.000 claims abstract description 14
- 229920001223 polyethylene glycol Polymers 0.000 claims abstract description 14
- KKEYFWRCBNTPAC-UHFFFAOYSA-L terephthalate(2-) Chemical compound [O-]C(=O)C1=CC=C(C([O-])=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-L 0.000 claims abstract description 14
- 238000001914 filtration Methods 0.000 claims abstract description 12
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- 238000002360 preparation method Methods 0.000 claims abstract description 10
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- 230000008018 melting Effects 0.000 claims abstract description 7
- 239000012535 impurity Substances 0.000 claims abstract description 6
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000004594 Masterbatch (MB) Substances 0.000 claims description 39
- 238000001179 sorption measurement Methods 0.000 claims description 14
- 239000000289 melt material Substances 0.000 claims description 12
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 10
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Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D7/00—Producing flat articles, e.g. films or sheets
- B29D7/01—Films or sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
- B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
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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
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
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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
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/665—Composites
- H01M4/667—Composites in the form of layers, e.g. coatings
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2250/00—Layers arrangement
- B32B2250/40—Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2457/00—Electrical equipment
- B32B2457/10—Batteries
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
- C08J2367/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/34—Silicon-containing compounds
- C08K3/36—Silica
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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
Abstract
The invention relates to a film preparation process of a current collector composite film, which comprises the following steps: conveying the polyester production melt to a metering pump through a pipeline, and filtering to obtain a main extrusion melt serving as an upper shallow surface layer and a lower shallow surface layer; melting and vacuumizing polyethylene glycol terephthalate slices and master batches in an auxiliary extruder, and filtering to remove water and impurities in the raw materials to obtain auxiliary extrusion melt serving as an upper surface layer and a lower surface layer; after the reclaimed leftover materials, leftover materials and waste materials are subjected to a tackifying process or polyethylene terephthalate chips are extruded in an extruder to form an intermediate melt serving as a core layer; the filtered main extrusion melt, the auxiliary extrusion melt and the intermediate melt are converged and extruded in a five-layer die head; the melt after mixing and extrusion is absorbed by static electricity through a cold roll to form a cast sheet; and forming a film by the cast sheet through a longitudinal stretching device, longitudinally cooling and shaping the film, then feeding the film into a transverse pulling device, and sequentially carrying out preheating, transverse stretching, transverse shaping and transverse cooling, and then carrying out traction and rolling.
Description
Technical Field
The invention relates to preparation of an electrode material in a lithium battery, in particular to a current collector composite film and a film preparation process thereof.
Background
The product is one of the materials for replacing electrode materials in the lithium battery, and the copper foil is adopted as the electrode material of the lithium battery generally, so that the copper foil plays a role in conducting electricity. The electrolytic copper foil has potential safety hazards such as capacity reduction, battery thermal runaway and the like. In the lithium battery industry, the current collector of the negative electrode which is mainly adopted at present is a pure copper electrolytic copper foil with the thickness of about 6-9 um. During the use process of charging and discharging of the battery, the volume of the negative electrode material is changed, the copper foil serving as a negative electrode current collector is stretched and contracted continuously, the negative electrode material is likely to fall off to cause potential safety hazards such as capacity reduction, performance reduction, resistance increase, heat production increase and the like. In addition, after the battery is damaged due to dendrite growth, external force and the like to cause thermal runaway, there is a safety risk that the battery knocks.
Therefore, there is an urgent need to develop an alternative electrode material for lithium batteries to solve the above problems.
Disclosure of Invention
The invention mainly aims at the problems and provides a current collector composite membrane and a membrane preparation process thereof, and aims to replace an electrode material in a lithium battery, ensure the safety of the battery and reduce the production cost.
In order to achieve the purpose, the invention provides a film making process of a current collector composite film, the current collector composite film is of an ABRBA type five-layer structure, wherein the layer A is an upper surface layer and a lower surface layer which are jointly composed of polyethylene terephthalate slices and master batches; the layer B is an upper shallow surface layer and a lower shallow surface layer which are composed of main melt materials; the R layer is a core layer consisting of tackifying reclaimed materials or polyethylene glycol terephthalate slices; the process comprises the following steps:
conveying the polyester production melt to a metering pump through a pipeline, and filtering to obtain a main extrusion melt serving as an upper shallow surface layer and a lower shallow surface layer;
melting and vacuumizing polyethylene glycol terephthalate slices and master batches in an auxiliary extruder, and filtering to remove water and impurities in the raw materials to obtain auxiliary extrusion melt serving as an upper surface layer and a lower surface layer;
after the reclaimed leftover materials, leftover materials and waste materials are subjected to a tackifying process or polyethylene terephthalate chips are extruded in an extruder to form an intermediate melt serving as a core layer;
the obtained filtered main extrusion melt, the auxiliary extrusion melt and the intermediate melt are converged and extruded in an ABRAB type five-layer die head;
the melt after mixing and extrusion is absorbed by static electricity through a cold roll to form a cast sheet;
and forming a film by the cast sheet through a longitudinal stretching device, longitudinally cooling and shaping the film, then feeding the film into a transverse pulling device, and sequentially carrying out preheating, transverse stretching, transverse shaping and transverse cooling, and then carrying out traction and rolling.
Further, the master batch is a high-concentration master batch, wherein the high-concentration master batch refers to master batch with the silicon dioxide content of 25000-50000 ppm; the grain diameter is 2.0-3.5 μm.
Further, 82% of polyethylene terephthalate chips and 18% of master batch were added to the layer a auxiliary extruder.
Further, the extrusion temperature of the convergent extrusion in a five-layer die head is 270-275 ℃, the voltage of electrostatic adsorption of the melt after the mixed extrusion, which is formed by electrostatic adsorption through a cold roll, is 10.00-10.60kV, and the current is 19-22mA.
Further, during the longitudinal stretching, the cast sheet is preheated at 68-109 ℃ and then longitudinally stretched at 113-118 ℃.
Further, double-point stretching is adopted during the longitudinal stretching, wherein the first stretching ratio is 1.7-1.75, and the second stretching ratio is 2.38-2.45.
Further, the transverse drawing comprises a transverse drawing preheating zone, a transverse drawing zone, a high-temperature shaping zone and transverse cooling, wherein the transverse drawing is carried out by preheating at 95-108 ℃, then transverse drawing is carried out at 108-120 ℃, then transverse high-temperature shaping is carried out at 187-225 ℃, and finally transverse cooling is carried out at 120-20 ℃.
Further, the MDO is a short term for a longitudinal stretching system, and during longitudinal stretching, the temperature of the MDO, the outlet tension of the MDO, the temperature and air volume of TDO (time difference of arrival) and the speed ratio of a traction area are adjusted, and the longitudinal thermal shrinkage rate of the current collector composite film is controlled to be less than 3%.
Further, TDO is a short for transverse stretching system, and during transverse stretching, the temperature and air volume of the TDO are adjusted, the chain width of a TDO shaping area and the chain width of a cooling area are adjusted, and the transverse heat shrinkage rate of the current collector composite film is controlled to be less than 2%.
In order to achieve the purpose, the invention also provides a current collector composite film which sequentially comprises an upper surface layer, an upper shallow surface layer, a core layer, a lower shallow surface layer and a lower surface layer from top to bottom, wherein the upper surface layer and the lower surface layer are jointly composed of polyethylene terephthalate slices and master batches, the optimal content of the polyethylene terephthalate slices is 82%, and the optimal content of the master batches is 18%; the upper shallow surface layer and the lower shallow surface layer are composed of polyester production melt; the core layer consists of tackifying reclaimed materials or polyethylene glycol terephthalate slices; so that the longitudinal tensile strength MD of the prepared current collector composite film is more than 300mpa, and the transverse tensile strength TD of the prepared current collector composite film is more than 250mpa; the haze of the current collector composite film is more than 3%; the roughness of the film surface of the current collector composite film is less than 120 nanometers.
Compared with the traditional copper foil, the current collector composite film prepared by adopting the technical scheme has the following advantages:
1. high safety: the current collector composite film prepared by the process is used as a composite copper foil intermediate layer to replace an electrode material in a lithium battery, so that the combustion safety of the battery can be greatly improved.
2. High specific volume: under the same condition, the using amount of copper is only 1/3-1/5 of the original using amount, and part of copper is replaced by plastic, so that the weight of the battery is lightened, and the energy density of the battery is increased;
3. long service life: the active substance falling caused by metal shrinkage is reduced, and the cycle life of the battery can be prolonged;
4. strong compatibility: the method is suitable for the environment of lithium batteries.
Drawings
Fig. 1 is a schematic structural diagram of a current collector composite according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a film forming process of a current collector composite film according to an embodiment of the present invention.
In the figure: 1. a copper stack base layer is arranged; 2. a PET current collector composite film; 3. and (5) a lower copper stack base layer.
Detailed Description
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientations and positional relationships indicated in the drawings, which are based on the orientations and positional relationships indicated in the drawings, and are used for convenience in describing the present invention and for simplicity in description, but do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The composite current collector material is like a safety fuse, and the acupuncture point is quickly disconnected after acupuncture, so that the safety of the battery is ensured. The PET composite copper foil is a good substitute material for the current collector (copper foil) of the traditional lithium battery, and as shown in fig. 1, the upper outer surface and the lower outer surface of the PET current collector composite film 2 in the middle layer are respectively an upper copper stack base layer 1 and a lower copper stack base layer 3. The composite copper film is 3/4 of the thickness of the traditional copper foil, and the weight is lighter. The method has important significance for improving the energy density, the safety and the cost of the lithium battery, and has wide market prospect. The technology has greater universality, and the composite copper foil film material can also use the technology. The composite copper foil is characterized in that a metal layer with the thickness of about 50-80 nanometers is manufactured on the surface of a plastic film with the thickness of 4-6 micrometers by adopting a vacuum copper deposition mode, the film is metalized, then the copper layer is thickened to 1 micrometer by adopting an aqueous medium electroplating mode, and the integral thickness of the composite copper foil is 5-8 micrometers, so that the traditional electrolytic copper foil is replaced. The PET composite copper foil can save about 2/3 of copper, obviously reduce the material cost, and further enlarge the cost reduction space of the battery cell after realizing mass production.
The present invention will be further described with reference to the following specific examples.
The embodiment is a PET current collector composite film, wherein the longitudinal and transverse stretching ratios are both more than 4, the longitudinal heat shrinkage MD is less than 3.0%, the transverse heat shrinkage TD is less than 2.0%, the haze is more than 3%, the longitudinal stretching strength MD is more than 300mpa, the transverse stretching strength TD is more than 250mpa, and the film surface roughness is less than 120 nm after the PET current collector composite film is continuously placed for 30 minutes in an environment at 150 ℃.
The PET current collector composite film 2 has an ABRBA type five-layer structure and comprises an upper surface layer A and a lower surface layer A which are jointly composed of polyethylene terephthalate slices and master batches, an upper shallow surface layer B and a lower shallow surface layer B which are composed of main melt materials, and a core layer R which is composed of tackifying reclaimed materials or polyethylene terephthalate slices.
The starting material used in this example was pet, scientific name polyethylene terephthalate. A biaxial stretching method is used. The specific process flow is shown in figure 2: (PET slices and PET master batches-an auxiliary extruder) and (PET melt) -a metering pump-a filter-a melt conveying pipeline-a die head-a casting sheet-longitudinal drawing-transverse drawing-thickness measuring-edge cutting-traction-rolling-object detection-slitting-quality detection-packaging-warehousing.
The first embodiment is as follows:
the film preparation process of the PET current collector composite film 2 comprises the following steps:
the method comprises the following steps: conveying the polyester production melt to a metering pump through a pipeline, and filtering to obtain a main extrusion melt serving as an upper shallow surface layer B and a lower shallow surface layer B;
step two: melting and vacuumizing polyethylene terephthalate slices and master batches in an auxiliary extruder, and filtering to remove water and impurities in the raw materials to obtain auxiliary extrusion melts serving as an upper surface layer A and a lower surface layer B;
step three: the reclaimed leftover materials, leftover materials and waste materials are subjected to a tackifying process or polyethylene glycol terephthalate slices are extruded in an extruder to form an intermediate melt serving as the core layer R, wherein the reclaimed leftover materials, leftover materials and waste materials are insufficient in viscosity, and therefore the reclaimed leftover materials, leftover materials and waste materials need to be subjected to the tackifying process to be used as the intermediate melt of the core layer R;
step four: the obtained filtered main extrusion melt, the auxiliary extrusion melt and the intermediate melt are converged and extruded in an ABRAB type five-layer die head, and the converging and extruding temperature is 270-275 ℃;
step five: the melt after mixing and extrusion is subjected to electrostatic adsorption through a cold roller to form a cast sheet, the voltage adopted by the electrostatic adsorption is 10.00-10.60kV, and the current is controlled at 19-22mA;
step six: preheating the cast sheet at 68-109 ℃ by a longitudinal stretching device, then longitudinally stretching at 113-118 ℃, and longitudinally cooling and shaping at 26-28 ℃ after the stretching ratio 1 adopted by double-point stretching is 1.7-1.75 and the stretching ratio 2 is 2.38-2.45; the shaped film directly enters a transverse drawing system for transverse drawing, is preheated at 95-108 ℃, transversely stretched at 108-120 ℃, transversely shaped at 187-225 ℃, transversely cooled at 120-20 ℃, and finally drawn and wound.
Compared with the commonly adopted slicing and indirect film drawing process at home and abroad, the melt straight drawing process has the advantages of higher quality, lower cost and larger scale.
The environmental purification grade in the production workshop reaches 10000 grades and completely meets the condition of developing and producing the current collector composite membrane by the project.
The ABRBA five layers are extruded together, so that the production cost is reduced, and the product performance is improved; wherein the layer A is an auxiliary extrusion melt material consisting of polyethylene glycol terephthalate slices and master batch; the layer B is a main extrusion melt material consisting of polyester production melt; the R layer is a tackifying reclaimed material or an intermediate melt material consisting of polyethylene terephthalate chips.
In the above examples, the higher the content of the master batch, the lower the clarity, the larger the particle size, and the too small content or particle size of the master batch did not function as an opening. In order to ensure the haze and the film surface roughness, the concentration and the addition amount of the master batch are controlled, in this embodiment, a high-concentration master batch with a particle size of 3.5 μm is used, so that the film surface smoothness can be further ensured, the haze is greater than 3%, and the high-concentration master batch refers to that the content of silica in the master batch is 25000ppm. For example, bester 1035K, which is 80% of polyethylene terephthalate chip and 20% of master batch. After the high-concentration master batch is added, the membrane surface roughness Ra is ensured to be less than 120 nanometers, so that the requirement of the polyester film is met.
The surface silicon content of the polyester film product is controlled to be more than 2500ppm by adjusting the thickness of the surface layer and controlling the surface thickness to be more than 1.8um, so that the surface particle size of the film is uniformly dispersed, and the surface smoothness can be improved.
In addition, the process parameters of production (MDO is short for longitudinal stretching system, and TDO is short for transverse stretching system) need to be strictly controlled, for example:
1) Adjusting the MDO temperature, the MDO outlet tension, the TDO temperature and air volume and the traction area speed ratio by the process, and controlling the longitudinal thermal shrinkage rate of the current collector composite film to be less than 3%; and adjusting the temperature and the air volume of the TDO, adjusting the chain width of a TDO shaping area and the chain width of a cooling area, and controlling the transverse heat shrinkage rate to be less than 2 percent.
A transverse stretch rail adjustment data is published as follows:
a preheating zone: preheating 1 2380mm, preheating 2 2380mm, preheating 3 2380mm.
Stretching area: stretching 1 3560mm, stretching 2 5840mm, stretching 3 8170mm, and stretching 4 9450mm.
A shaping area: 1 9450mm for shaping, 2 9450mm for shaping, 3 9450mm for shaping,
the shaping is 4 9360mm and the shaping is 5 9260mm.
A cooling area: cooling for 1:9160mm, cool 3 right: 9160mm.
2) The process adjusts the bolt gap of the die head, the temperature of the bolts and the MDO temperature, regularly cleans the electrostatic adsorption system and the MDO roller for sanitation, and regularly replaces the melt filter, so that the thickness smoothness of the current collector composite film is controlled, and the average deviation 2-sigma value of the thickness is smaller than 1.5%.
The second embodiment:
the film preparation process of the PET current collector composite film 2 comprises the following steps:
the method comprises the following steps: conveying the polyester production melt to a metering pump through a pipeline, and filtering to obtain a main extrusion melt serving as an upper shallow surface layer B and a lower shallow surface layer B;
step two: melting and vacuumizing polyethylene glycol terephthalate slices and master batches in an auxiliary extruder, and filtering to remove water and impurities in the raw materials to obtain auxiliary extrusion melt serving as an upper surface layer A and a lower surface layer B;
step three: after the reclaimed leftover materials, leftover materials and waste materials are subjected to a tackifying process or polyethylene glycol terephthalate slices are extruded in an extruder to form an intermediate melt serving as a core layer R, wherein the reclaimed leftover materials, leftover materials and waste materials are insufficient in viscosity, so that the reclaimed leftover materials, leftover materials and waste materials are required to be used as the intermediate melt of the core layer R after the viscosity is improved through a once-bonding process;
step four: the obtained filtered main extrusion melt, the auxiliary extrusion melt and the intermediate melt are converged and extruded in an ABRAB type five-layer die head, and the converging and extruding temperature is 270-275 ℃;
step five: the melt after mixing and extrusion is subjected to electrostatic adsorption through a cold roller to form a cast sheet, the voltage adopted by the electrostatic adsorption is 10.00-10.60kV, and the current is controlled at 19-22mA;
step six: preheating the cast sheet at 68-109 ℃ by a longitudinal stretching device, then longitudinally stretching at 113-118 ℃, and longitudinally cooling and shaping at 26-28 ℃ after the stretching ratio 1 adopted by double-point stretching is 1.7-1.75 and the stretching ratio 2 is 2.38-2.45; the shaped film directly enters a transverse drawing system for transverse drawing, is preheated at 95-108 ℃, transversely stretched at 108-120 ℃, transversely shaped at 187-225 ℃, transversely cooled at 120-20 ℃, and finally drawn and wound.
Compared with the commonly adopted chip indirect film drawing process at home and abroad, the embodiment has the advantages of higher quality, lower cost and larger scale.
The environmental purification grade in the production workshop reaches 10000 grades and completely meets the condition of the current collector composite film developed and produced by the project.
The ABRBA five layers are extruded together, so that the production cost is reduced, and the product performance is improved; wherein the layer A is an auxiliary extrusion melt material consisting of polyethylene glycol terephthalate slices and master batch; the layer B is a main extrusion melt material consisting of polyester production melt; the R layer is a tackifying reclaimed material or an intermediate melt material consisting of polyethylene terephthalate chips.
In the above examples, the higher the content of the master batch, the lower the clarity, the larger the particle size, and the too small content or particle size of the master batch did not function as an opening. In order to ensure the haze and the film surface roughness, the concentration and the addition amount of the master batch are controlled, in this embodiment, a high-concentration master batch with a particle size of 2.5 μm is used, so that the film surface smoothness can be further ensured, the haze is greater than 3%, and the high-concentration master batch refers to that the content of silica in the master batch is 30000ppm. Such as best 1025K, etc. The proportion of the master batch is 82 percent of polyethylene terephthalate slices and 18 percent of master batch. After the high-concentration master batch is added, the roughness Ra of the film surface is ensured to be less than 120 nanometers, so that the requirement of the polyester film is met.
The surface silicon content of the polyester film product is controlled to be more than 2500ppm by adjusting the thickness of the surface layer and controlling the surface thickness to be more than 1.8um, so that the surface particle size of the film is uniformly dispersed, and the surface smoothness can be improved.
In addition, the process parameters of production (MDO is short for longitudinal stretching system, and TDO is short for transverse stretching system) need to be strictly controlled, for example:
1) Adjusting the MDO temperature, the MDO outlet tension, the TDO temperature and air volume and the traction area speed ratio by the process, and controlling the longitudinal thermal shrinkage rate of the current collector composite film to be less than 3%; and adjusting the temperature and the air volume of the TDO, adjusting the chain width of a TDO shaping area and the chain width of a cooling area, and controlling the transverse heat shrinkage rate to be less than 2% and the like.
A transverse tension rail adjustment data is published as follows:
a preheating zone: preheating 1 2380mm, preheating 2 2380mm, preheating 3 2380mm.
Stretching area: stretching 1 3560mm, stretching 2 5840mm, stretching 3 8170mm, and stretching 4 9450mm.
A shaping area: 1 9450mm for shaping, 2 9450mm for shaping, 3 9450mm for shaping,
sizing 4 9360mm, and sizing 5 9260mm.
A cooling area: cooling for 1:9160mm, cooling for 3 mm: 9160mm.
2) The process adjusts the bolt gap of the die head, the temperature of the bolts and the MDO temperature, regularly cleans the electrostatic adsorption system and the MDO roller for sanitation, and regularly replaces the melt filter, so that the thickness smoothness of the current collector composite film is controlled, and the average deviation 2-sigma value of the thickness is smaller than 1.5%.
Example three:
the film preparation process of the PET current collector composite film 2 comprises the following steps:
the method comprises the following steps: conveying the polyester production melt to a metering pump through a pipeline, and filtering to obtain a main extrusion melt serving as an upper shallow surface layer B and a lower shallow surface layer B;
step two: melting and vacuumizing polyethylene glycol terephthalate slices and master batches in an auxiliary extruder, and filtering to remove water and impurities in the raw materials to obtain auxiliary extrusion melt serving as an upper surface layer A and a lower surface layer B;
step three: the reclaimed leftover materials, leftover materials and waste materials are subjected to a tackifying process or polyethylene terephthalate slices are extruded in an extruder to form an intermediate melt serving as the core layer R, wherein the reclaimed leftover materials, leftover materials and waste materials are insufficient in viscosity, and therefore the reclaimed leftover materials, leftover materials and waste materials are required to be used as the intermediate melt of the core layer R after the viscosity is improved through a once-bonding process;
step four: the obtained filtered main extrusion melt, the auxiliary extrusion melt and the intermediate melt are converged and extruded in an ABRAB type five-layer die head, and the converging and extruding temperature is 270-275 ℃;
step five: the melt after mixing and extrusion is subjected to electrostatic adsorption through a cold roller to form a cast sheet, the voltage adopted by the electrostatic adsorption is 10.00-10.60kV, and the current is controlled at 19-22mA;
step six: preheating the cast sheet at 68-109 ℃ by a longitudinal stretching device, then longitudinally stretching at 113-118 ℃, wherein the stretching ratio 1 adopted by double-point stretching is 1.7-1.75, the stretching ratio 2 is 2.38-2.45, and then longitudinally cooling and shaping at 26-28 ℃; the shaped film directly enters a transverse drawing system for transverse drawing, is preheated at 95-108 ℃, transversely stretched at 108-120 ℃, transversely shaped at 187-225 ℃, transversely cooled at 120-20 ℃, and finally drawn and wound.
Compared with the commonly adopted slicing and indirect film drawing process at home and abroad, the melt straight drawing process has the advantages of higher quality, lower cost and larger scale.
The environmental purification grade in the production workshop reaches 10000 grades and completely meets the condition of developing and producing the current collector composite membrane by the project.
The ABRBA five layers are extruded together, so that the production cost is reduced, and the product performance is improved; wherein the layer A is an auxiliary extrusion melt material consisting of polyethylene glycol terephthalate slices and master batch; the layer B is a main extrusion melt material consisting of polyester production melt; the R layer is a tackifying reclaimed material or an intermediate melt material consisting of polyethylene terephthalate chips.
In the above examples, the higher the content of the master batch, the lower the clarity, the larger the particle size, and the too small content or particle size of the master batch did not function as an opening. In order to ensure the haze and the film surface roughness, the concentration and the addition amount of the master batch are controlled, in this embodiment, a high-concentration master batch with a particle size of 2.0 μm is used, so that the film surface smoothness can be further ensured, the haze is greater than 3%, and the high-concentration master batch refers to that the content of silica in the master batch is 50000ppm. Such as best 1020K, etc. The proportion of the master batch is 90 percent of polyethylene glycol terephthalate slices and 10 percent of master batch. After the high-concentration master batch is added, the membrane surface roughness Ra is ensured to be less than 120 nanometers, so that the requirement of the polyester film is met.
The surface silicon content of the polyester film product is controlled to be more than 2500ppm by adjusting the thickness of the surface layer and controlling the surface thickness to be more than 1.8um, so that the surface particle size of the film is uniformly dispersed, and the surface smoothness can be improved.
In addition, the production process parameters (MDO is short for longitudinal stretching system, and TDO is short for transverse stretching system) need to be strictly controlled, for example:
1) Adjusting the MDO temperature, the MDO outlet tension, the TDO temperature and air volume and the traction area speed ratio by the process, and controlling the longitudinal thermal shrinkage rate of the current collector composite film to be less than 3%; and adjusting the temperature and the air volume of the TDO, adjusting the chain width of a TDO shaping area and the chain width of a cooling area, and controlling the transverse heat shrinkage rate to be less than 2 percent.
A transverse tension rail adjustment data is published as follows:
a preheating zone: preheating 1 2380mm, preheating 2 2380mm, preheating 3 2380mm.
Stretching area: stretching 1 3560mm, stretching 2 5840mm, stretching 3 8170mm, and stretching 4 9450mm.
A shaping area: 1 9450mm for shaping, 2 9450mm for shaping, 3 9450mm for shaping,
sizing 4 9360mm, and sizing 5 9260mm.
A cooling area: cooling 1:9160mm, cool 3 right: 9160mm.
2) The process adjusts the bolt gap of the die head, the temperature of the bolts and the MDO temperature, regularly cleans the electrostatic adsorption system and the MDO roller for sanitation, and regularly replaces the melt filter, so that the thickness smoothness of the current collector composite film is controlled, and the average deviation 2-sigma value of the thickness is smaller than 1.5%.
In summary, in the film-making process of the current collector composite film in the above embodiment, after the polyester melt directly produced by the direct melting production line is subjected to die head sheet casting, a current collector composite film sheet is obtained; the current collector composite film is subjected to longitudinal drawing and transverse drawing treatment sequentially through a longitudinal drawing machine and a transverse drawing machine to obtain a current collector composite initial film; and rolling the current collector composite initial film after thickness measurement, edge cutting and traction treatment to obtain the current collector composite film. The prepared current collector composite membrane has the advantages of smooth surface, good temperature resistance, high strength and greatly shortened process flow, the membrane surface formed by adopting a vacuum coating process is used as a cathode, the reaction can be directly carried out in ion replacement equipment, and the vacuum process is pollution-free; by adopting a novel medicament system, extremely toxic substances such as cyanide and the like are avoided, so that the pollution discharge amount in the production process is better, and pollutants are easier to treat; the antioxidation adopts organic antioxidation liquid, the antioxidation directly carries out drying process, and the medicament is recycled. The discharge of metal pollutants is avoided.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, it is possible to make various improvements and modifications without departing from the technical principle of the present invention, and those improvements and modifications should be also considered as the protection scope of the present invention.
Claims (10)
1. A film making process of a current collector composite film is characterized in that the current collector composite film is of an ABRBA five-layer structure, wherein an A layer is an upper surface layer and a lower surface layer which are jointly composed of polyethylene terephthalate chips and master batches; the B layer is an upper shallow surface layer and a lower shallow surface layer which are composed of main melt materials; the R layer is a core layer consisting of tackifying reclaimed materials or polyethylene terephthalate slices; the process comprises the following steps:
conveying the polyester production melt to a metering pump through a pipeline, and filtering to obtain a main extrusion melt serving as an upper shallow surface layer and a lower shallow surface layer;
melting and vacuumizing polyethylene glycol terephthalate slices and master batches in an auxiliary extruder, and filtering to remove water and impurities in the raw materials to obtain auxiliary extrusion melt serving as an upper surface layer and a lower surface layer;
after the reclaimed leftover materials, leftover materials and waste materials are subjected to a tackifying process or polyethylene glycol terephthalate slices are extruded in an extruder to form an intermediate melt serving as a core layer;
the obtained filtered main extrusion melt, the auxiliary extrusion melt and the intermediate melt are converged and extruded in an ABRAB type five-layer die head;
the melt after mixing and extrusion is subjected to electrostatic adsorption through a cold roller to form a cast sheet;
and forming a film by the cast sheet through a longitudinal stretching device, longitudinally cooling and shaping the film, then feeding the film into a transverse stretching device, and sequentially carrying out preheating, transverse stretching, transverse shaping and transverse cooling, and then carrying out traction and winding.
2. The film preparation process of the current collector composite film according to claim 1, wherein the master batch is a high-concentration master batch, and the high-concentration master batch refers to master batch with the silica content of 25000-50000 ppm; the grain diameter is 2.0-3.5 μm.
3. The process for preparing a current collector composite film according to claim 1, wherein 82% of polyethylene terephthalate chips and 18% of master batch are added into the A-layer auxiliary extruder.
4. The film-making process of the current collector composite film as claimed in claim 1, wherein the extrusion temperature of the merged extrusion in the five-layer die head is 270-275 ℃, the voltage for electrostatic adsorption of the melt after the mixed extrusion, which is formed into a cast sheet by electrostatic adsorption through a cold roll, is 10.00-10.60kV, and the current is 19-22mA.
5. The current collector composite film preparation process of claim 1, wherein during the longitudinal stretching, the casting sheet is preheated to 68-109 ℃ and then longitudinally stretched at 113-118 ℃.
6. The process for preparing a current collector composite film according to claim 1, wherein the longitudinal stretching is performed by double-point stretching, wherein the first stretching ratio is 1.7-1.75, and the second stretching ratio is 2.38-2.45.
7. The current collector composite film preparation process of claim 1, wherein the transverse drawing comprises a transverse drawing preheating zone, a transverse drawing zone, a high temperature shaping zone and transverse cooling, wherein the transverse drawing is performed by preheating at 95-108 ℃, then transverse drawing at 108-120 ℃, then transverse high temperature shaping at 187-225 ℃ and finally transverse cooling at 120-20 ℃.
8. The film-making process of the current collector composite film according to claim 1, wherein during the longitudinal stretching, the longitudinal thermal shrinkage rate of the current collector composite film is controlled to be less than 3% by adjusting the MDO temperature, the MDO outlet tension, the TDO temperature and the air volume and the traction area speed ratio.
9. The film-making process of the current collector composite film according to claim 1, wherein during the transverse drawing, the TDO temperature and the air volume are adjusted, the TDO setting area chain width and the cooling area chain width are adjusted, and the transverse heat shrinkage rate of the current collector composite film is controlled to be less than 2%.
10. The current collector composite film produced by the film making process according to any one of claims 1 to 9, which comprises an upper surface layer, an upper shallow surface layer, a core layer, a lower shallow surface layer and a lower surface layer from top to bottom in sequence, wherein the upper surface layer and the lower surface layer are jointly composed of polyethylene terephthalate chips and master batches, wherein the content of the polyethylene terephthalate chips is 82%, and the content of the master batches is 18%; the upper shallow surface layer and the lower shallow surface layer are composed of polyester production melt; the core layer is composed of tackifying reclaimed materials or polyethylene terephthalate chips.
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| CN116120722A (en) * | 2023-02-21 | 2023-05-16 | 佛山杜邦鸿基薄膜有限公司 | Polyester film suitable for composite current collector and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106827568A (en) * | 2017-02-08 | 2017-06-13 | 营口康辉石化有限公司 | A kind of polyester film production technology of use reclaimed materials |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106827568A (en) * | 2017-02-08 | 2017-06-13 | 营口康辉石化有限公司 | A kind of polyester film production technology of use reclaimed materials |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116120722A (en) * | 2023-02-21 | 2023-05-16 | 佛山杜邦鸿基薄膜有限公司 | Polyester film suitable for composite current collector and preparation method thereof |
| CN116120722B (en) * | 2023-02-21 | 2023-11-24 | 佛山杜邦鸿基薄膜有限公司 | Polyester film suitable for composite current collector and preparation method thereof |
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