CN111409297A - Preparation method of coating film, coating film and battery - Google Patents
Preparation method of coating film, coating film and battery Download PDFInfo
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- CN111409297A CN111409297A CN202010239417.9A CN202010239417A CN111409297A CN 111409297 A CN111409297 A CN 111409297A CN 202010239417 A CN202010239417 A CN 202010239417A CN 111409297 A CN111409297 A CN 111409297A
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- 239000011248 coating agent Substances 0.000 title claims abstract description 111
- 238000000576 coating method Methods 0.000 title claims abstract description 111
- 238000002360 preparation method Methods 0.000 title claims abstract description 30
- 239000000203 mixture Substances 0.000 claims abstract description 49
- 230000008018 melting Effects 0.000 claims abstract description 31
- 238000002844 melting Methods 0.000 claims abstract description 30
- 239000000463 material Substances 0.000 claims abstract description 29
- 239000000945 filler Substances 0.000 claims abstract description 18
- 238000002156 mixing Methods 0.000 claims abstract description 16
- 238000001035 drying Methods 0.000 claims abstract description 13
- 238000003756 stirring Methods 0.000 claims abstract description 11
- 238000010438 heat treatment Methods 0.000 claims abstract description 8
- 238000001125 extrusion Methods 0.000 claims abstract description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 16
- 239000000377 silicon dioxide Substances 0.000 claims description 12
- 239000011231 conductive filler Substances 0.000 claims description 7
- 235000012239 silicon dioxide Nutrition 0.000 claims description 5
- 238000004804 winding Methods 0.000 claims description 5
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 239000002245 particle Substances 0.000 claims description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 3
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 2
- 239000010408 film Substances 0.000 claims 14
- 239000013039 cover film Substances 0.000 claims 7
- 230000017525 heat dissipation Effects 0.000 abstract description 20
- 229920000139 polyethylene terephthalate Polymers 0.000 description 12
- 239000005020 polyethylene terephthalate Substances 0.000 description 12
- 238000009825 accumulation Methods 0.000 description 8
- 238000005253 cladding Methods 0.000 description 8
- 239000004642 Polyimide Substances 0.000 description 7
- 239000004743 Polypropylene Substances 0.000 description 7
- 229920001721 polyimide Polymers 0.000 description 7
- 229920001155 polypropylene Polymers 0.000 description 7
- 238000002425 crystallisation Methods 0.000 description 5
- 230000008025 crystallization Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 239000004698 Polyethylene Substances 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 238000004806 packaging method and process Methods 0.000 description 3
- 229920000573 polyethylene Polymers 0.000 description 3
- -1 polyethylene terephthalate Polymers 0.000 description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 229920001730 Moisture cure polyurethane Polymers 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000010309 melting process Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
Images
Classifications
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- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/61—Types of temperature control
- H01M10/613—Cooling or keeping cold
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/62—Heating or cooling; Temperature control specially adapted for specific applications
- H01M10/625—Vehicles
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/65—Means for temperature control structurally associated with the cells
- H01M10/653—Means for temperature control structurally associated with the cells characterised by electrically insulating or thermally conductive materials
-
- 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
- H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
- H01M50/116—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2467/00—Use of polyesters or derivatives thereof as filler
- B29K2467/003—PET, i.e. polyethylene terephthalate
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2509/00—Use of inorganic materials not provided for in groups B29K2503/00 - B29K2507/00, as filler
-
- 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 belongs to the technical field of power batteries, and particularly discloses a preparation method of a coating film, which comprises the following steps: s1: mixing a film base material with a melting point higher than 180 ℃ and a heat-conducting filler according to a first preset weight proportion to form a first mixture; s2: stirring and heating the first mixture to pre-crystallize the first mixture; s3: drying the pre-crystallized first mixture, and then performing melt extrusion to form a film; s4: and stretching the film to form a coating film. The preparation method of the coating film provided by the invention is simple and feasible, and the prepared coating film has high melting point and high heat dissipation efficiency because the film base material has high melting point and the heat-conducting filler has high heat conductivity coefficient. The invention also discloses a coating film and a battery, wherein the coating film is prepared by adopting the preparation method of the coating film, and the heat dissipation efficiency and the reliability of the coating film are improved. The battery comprises the coating film, and the stability and the reliability of the battery are improved.
Description
Technical Field
The invention relates to the technical field of power batteries, in particular to a preparation method of a coating film, the coating film and a battery.
Background
The aluminum shell lithium battery is used as a common power source, can stably supply power for a long time, is convenient to carry, has stable and reliable performance, and has wide application prospects in various aspects such as portable electronic equipment and electric automobiles.
When the existing automotive aluminum shell lithium battery is assembled, the cladding film is used for wrapping the internal core cladding, so that the insulation protection of the core cladding and the aluminum shell is realized. The materials of the commonly used insulating coating film are generally PE with good insulating property, but the coating film made of the materials has low melting point and low heat conductivity coefficient, so that the heat dissipation effect of a core package in the battery in the charging and discharging and normal use process is poor, the heat accumulation in the battery is easily caused, and the risk of thermal runaway of the battery is increased. Meanwhile, the heat accumulation in the core bag causes the shrinkage and even the rupture of the low-melting-point coating film, so that certain potential safety hazard exists, and the safety and the reliability of the aluminum-shell battery are reduced.
Therefore, a preparation method of the coating film, the coating film and the battery are needed to solve the problems of low melting point and low heat dissipation efficiency of the coating film in the aluminum-shell battery.
Disclosure of Invention
The invention aims to provide a preparation method of a coating film, which aims to solve the technical problems of low melting point and low heat dissipation efficiency of the coating film and improve the melting point and the heat dissipation efficiency of the coating film.
The invention also aims to provide a coating film to solve the technical problems of low melting point and low heat dissipation efficiency of the coating film and improve the melting point and the heat dissipation efficiency of the coating film.
Another object of the present invention is to provide a battery, which solves the technical problems of low melting point and low heat dissipation efficiency of the coating film, and improves the safety and stability of the battery.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a preparation method of a coating film comprises the following steps:
s1: mixing a film base material with a melting point higher than 180 ℃ and a heat-conducting filler according to a first preset weight proportion to form a first mixture;
s2: stirring and heating the first mixture to pre-crystallize the first mixture;
s3: drying the pre-crystallized first mixture, and then performing melt extrusion to form a film;
s4: and stretching the film to form a coating film.
Further, the first preset weight ratio is 1: (0.1-0.5).
Further, the film base material is any one of PI, PP or PET.
Further, the heat conducting filler is a second mixture obtained by mixing any one of silicon dioxide, aluminum oxide and silicon nitride with the corresponding prepolymer of the film base material in a second preset weight ratio, and the second preset weight ratio is 1: (1.5-3.5).
Further, step S4 includes:
s41: longitudinally stretching the film according to a preset longitudinal stretching proportion;
s42: and transversely stretching the film according to a preset transverse stretching ratio to form a coating film.
Further, the preset longitudinal stretching ratio and the preset transverse stretching ratio are respectively 1: (3-5) and 1: (3-7).
Further, step S4 is followed by step S5: and winding and slitting the coating film.
Further, the particle size value of the heat-conducting filler is less than or equal to 20 μm.
A coating film is used for insulating and packaging a core package of a battery and is prepared by the preparation method of the coating film.
A battery comprises the coating film.
The invention has the beneficial effects that:
the preparation method of the coating film comprises the steps of mixing a film base material with a melting point higher than 180 ℃ and a heat-conducting filler according to a first preset weight proportion to form a first mixture, stirring and heating the mixture to pre-crystallize the first mixture, melting and extruding the pre-crystallized first mixture to form the film, and finally stretching the film to form the coating film. Compared with the existing preparation method of the cladding film, the method is simple and easy to implement, and the film base material has a higher melting point, and the heat-conducting filler has a higher heat-conducting coefficient, so that the cladding film prepared by the preparation method of the cladding film has a high melting point, the cladding film is not easy to shrink, and the heat stability inside the core bag is improved.
The coating film provided by the invention is prepared by the preparation method of the coating film, has higher melting point and heat conductivity coefficient, is not easy to shrink, and improves the heat dissipation efficiency of the coating film.
The battery provided by the invention comprises the coating film, and the coating film in the battery has higher melting point and heat conductivity coefficient, so that the coating film is not easy to shrink, and meanwhile, the core cladding has higher heat dissipation efficiency, and the stability and reliability of the battery are improved.
Drawings
Fig. 1 is a flowchart of a method for manufacturing a coating film according to an embodiment of the present invention.
Detailed Description
In order to make the technical problems solved, the technical solutions adopted and the technical effects achieved by the present invention clearer, the technical solutions of the present invention are further described below by way of specific embodiments with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the elements associated with the present invention are shown in the drawings.
In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
In the description of the present embodiment, the terms "upper", "lower", "right", etc. are used in an orientation or positional relationship based on that shown in the drawings only for convenience of description and simplicity of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.
The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.
Example one
Fig. 1 is a flowchart of a method for manufacturing a coating film according to an embodiment of the present invention. Referring to fig. 1, the present embodiment discloses a method for preparing a coating film, including S1: mixing a film base material with a melting point higher than 180 ℃ and a heat-conducting filler in a first preset weight proportion to form a first mixture, S2: stirring and heating the first mixture to form a pre-crystal of the first mixture, S3: melt-extruding the pre-crystallized first mixture after drying into a film, S4: and stretching the film to form a coating film. Compared with the existing preparation method of the clad film, the method is simple and easy to implement, and the film base material has a higher melting point, and the heat-conducting filler has a higher heat-conducting coefficient, so that the heat dissipation efficiency of the clad film is improved. Meanwhile, the coating film has a high heat conductivity coefficient, the heat dissipation efficiency of the coating film is improved, the heat accumulation in the core bag is reduced, the risk of thermal runaway of the core bag is reduced, and the stability and reliability of the core bag are improved.
It is noted that the thermally conductive filler is a second mixture of any one of silica, alumina and silicon nitride mixed with a prepolymer of a corresponding film base in a second predetermined weight ratio. For ease of understanding and description, in the first, second and third examples, the description of the thermally conductive filler is given by taking as an example a second mixture obtained by mixing silica with a prepolymer of the corresponding film base material in a second predetermined weight ratio.
In this embodiment, the film base material is polyethylene terephthalate (PET), and the PET has a higher melting point. The heat-conducting filler is a second mixture of silicon dioxide and a prepolymer of PET, and has good heat-conducting property. The first mixture obtained by stirring and mixing the film base material and the heat-conducting filler in a stirrer according to a first preset weight proportion is used as a raw material for preparing the coating film. Compared with the traditional coating film which generally uses Polyethylene (PE) with good insulativity but lower melting point and heat conductivity coefficient, the coating film prepared by the preparation method of the coating film disclosed by the embodiment has higher melting point and heat dissipation efficiency, the coating film is not easy to shrink, the heat accumulation in the core bag is reduced, and the heat stability and the heat dissipation efficiency in the core bag are improved.
Preferably, the first preset weight ratio is 1: (0.1-0.5). Mixing the film base material and the heat-conducting filler in a ratio of 1: (0.1-0.5) placing the mixture into a stirrer to be stirred and mixed to obtain a first mixture. Further preferably, the first preset weight ratio is 1: 0.3, mixing the film base material and the heat-conducting filler in a ratio of 1: the first mixture obtained by mixing the components in the weight ratio of 0.3 has good comprehensive performance, namely high melting point and good heat dissipation effect. In other embodiments, the first preset weight ratio may also be 1: 0.1, 1: 0.2, 1: 0.4 and 1: 0.5, etc.
Preferably, the second preset weight ratio is 1: (1.5-3.5), further preferably, the second preset weight ratio is 1: 2.3. pre-polymer of silica with PET in a ratio of 1: 2.3, stirring and mixing the mixture in a stirrer according to a second preset weight proportion to obtain a second mixture, wherein the second mixture has a high heat conductivity coefficient, so that the prepared coating film has a good heat dissipation effect. In other embodiments, the second preset weight ratio may also be 1: 1.5, 1: 2. 1: 2.5, 1: 3 and 1: 3.5, etc. The film base material PET and the heat-conducting filler are stirred and mixed according to a first preset weight proportion to finally obtain a first mixture for preparing the coating film. Wherein the rotating speed of the stirrer is 1000rpm, and the set temperature in the stirrer is 25-30 ℃. It should be noted that the particle size of the silica and the PET prepolymer in the heat conductive filler is not greater than 20 μm, so as to avoid the poor surface flatness and gloss of the prepared coating film, which affects the overall quality of the coating film.
The pre-crystallization process of the first mixture can be carried out in a common reaction kettle or a drying box, and can also be carried out in a mechanical dryer similar to a high-speed mixer, and the pre-crystallization of the first mixture can increase the melting temperature of the first mixture, so that the phenomenon of agglomeration of the first mixture in the subsequent melting and heating process is prevented. When a reaction kettle or a drying box is adopted for pre-crystallization treatment, the internal temperature of the reaction kettle or the drying box is 150-165 ℃, the stirring speed is 15rpm, and the stirring and heating time is 1.5 hours.
In the present embodiment, step S4 includes steps S41 and S42, step S41: longitudinally stretching the film according to a preset longitudinal stretching ratio, and performing step S42: and transversely stretching the film according to a preset transverse stretching ratio to form a coating film. Stretching the film in step S4 includes stretching the film in the machine direction and stretching the film in the transverse direction. It should be noted that the preset longitudinal stretching ratio and the preset transverse stretching ratio are respectively 1: (3-5) and 1: (3-7), further preferably, the preset longitudinal stretching ratio is 1: 4, presetting a transverse stretching ratio as 1: 6, for the film, the ratio of 1: 4 and a preset longitudinal stretching ratio of 1: 6, stretching according to the preset transverse stretching proportion to obtain the coating film with good mechanical property. In other embodiments, the preset longitudinal stretch ratio may also be 1: 3. 1: 3.5, 1: 4.5 and 1: 5, and the like. Similarly, the preset transverse stretching ratio can also be 1: 3. 1: 4. 1: 5 and 1: 7, and the like. The ambient temperature during stretching was set to 135 ℃, and the ambient temperature during setting of the coating film was set to 250 ℃. In order to improve the stretching quality of the film and avoid the film from being damaged due to the direct transverse stretching of the film, the stretching sequence of the film is that longitudinal stretching is firstly carried out and then transverse stretching is carried out. The extruded film is longitudinally and transversely stretched in two directions, so that the mechanical properties of the coating film, such as tensile strength, tensile elastic modulus, breaking strength and the like, are improved, the characteristics of transparency, glossiness and the like of the film can be improved, and finally the performance requirements of the coating film are met.
With reference to fig. 1, step S4 is followed by step S5, after the film is stretched and shaped to form a coating film, the shaped coating film is conveyed to a winding shaft of a slitter to be wound, and then enters a slitting process, the film roll of the coating film is trimmed by a cutter to remove scraps and waste materials, and slit according to a preset specification according to the use and/or storage requirements of the coating film, and finally, the film roll is subjected to quality inspection and is stored, sold or used.
For convenience of understanding, the preparation method and the flow of the coating film in the embodiment are as follows:
a prepolymer of silica and PET was first prepared in a 1: (1.5-3.5) in a second predetermined weight ratio into the blender and blending to obtain a second mixture, and then blending the film base PET with the second mixture in a ratio of 1: (0.1-0.5) stirring and mixing the mixture according to the first preset weight proportion to finally obtain a first mixture for preparing the coating film. And then conveying the first mixture into a reaction kettle, continuously stirring and heating the mixture, carrying out pre-crystallization, and putting the pre-crystallized first mixture into a drying container for drying, wherein the temperature set in the drying container is 120 ℃, and the drying time is two hours. Then, the dried first mixture was heated and melted and a film was extruded through a twin screw machine in which the rotation speed of the screw was set to 80rpm, the temperature was set to 250 ℃ and the degree of vacuum of evacuation was 0.18 MPa. And then sequentially carrying out longitudinal stretching and transverse stretching on the film by stretching equipment until the film is shaped into a qualified coating film.
And finally, conveying the shaped coating film to a winding shaft of a splitting machine for winding, then entering a splitting process, cutting off edges and/or waste materials of the film roll of the coating film through a cutter, splitting according to preset specifications according to the use and/or storage requirements of the coating film, and finally warehousing, storing, selling or using after quality inspection.
The preparation method of the coating film provided by the embodiment is simple and easy to implement, and the film base material has a higher melting point, and the heat-conducting filler can improve the heat conductivity coefficient of the coating film, so that the coating film prepared by the preparation method of the coating film has a high melting point, the coating film is not easy to shrink, and the thermal stability inside the core bag is improved. Meanwhile, the coating film has a high heat conductivity coefficient, the heat dissipation efficiency of the coating film is improved, the heat accumulation in the core bag is reduced, the risk of thermal runaway of the core bag is reduced, and the stability and reliability of the core bag are improved.
The embodiment also discloses a battery, which adopts the coating film to carry out the insulation packaging of the core package, and the battery comprises the core package, the coating film, a shell and a top cover capable of covering the shell. Firstly, welding the core package and the top cover, then wrapping the core package by using a wrapping film, then placing the core package wrapped with the wrapping film into the shell, and combining, welding and fixing the top cover and the shell cover, thus finishing the packaging of the battery. The coating film used by the battery has higher melting point and heat conductivity coefficient, reduces the heat accumulation in the battery, reduces the risk of thermal runaway of the battery, and improves the stability and reliability of the battery.
Example two
The embodiment also discloses a preparation method of the coating film, the coating film and a battery, the preparation method of the coating film is the same as the equipment and the preparation flow used by the preparation method of the coating film in the first embodiment, and the main difference between the two is that:
the film base material used in this example is Polypropylene (PP), the heat conductive filler is a mixture of silica and PP prepolymer, and the first predetermined weight ratio and the second predetermined weight ratio are the same as the first predetermined weight ratio and the second predetermined weight ratio in the first example.
Because the characteristics of the PP material are different from those of the PET material, the pre-crystallization of the coating film is carried out, and then the coating film enters a drying process, and the set temperature in a drying container is 125 ℃. When the film was extruded by the twin-screw extruder, the rotation speed of the screw was set at 85rpm and the temperature was 166 ℃. When the film is sequentially longitudinally stretched and transversely stretched by using stretching equipment, the environment temperature during stretching is 110 ℃, and the environment temperature around the film is 155 ℃ during shaping of the coating film.
In the embodiment, PP is used as a film base material, a mixture of silicon dioxide and PP prepolymer is used as a heat-conducting filler, and the coating film prepared by the preparation method of the coating film has a high melting point, so that the coating film is not easy to shrink, and the thermal stability in the core bag is improved. Meanwhile, the coating film has a high heat conductivity coefficient, so that the heat dissipation efficiency of the core bag is improved, the heat accumulation in the core bag is reduced, the risk of thermal runaway of the core bag is reduced, and the stability and reliability of the core bag are improved.
EXAMPLE III
The embodiment also discloses a preparation method of the coating film, the coating film and a battery, the preparation method of the coating film is the same as the equipment and the preparation process used in the preparation method of the coating film in the first embodiment, and the main difference between the two is that:
the film base material used in this embodiment is Polyimide (PI), the heat conductive filler is a second mixture of silica and PI prepolymer, and the first predetermined weight ratio and the second predetermined weight ratio are the same as the first predetermined weight ratio and the second predetermined weight ratio in the first embodiment.
Since the PI material is different from the PET material in characteristics, when the film is extruded by the double-screw machine, the rotating speed of the screw of the double-screw machine is set to be 100rpm, the ambient temperature is set to be 340 ℃, and the exhaust vacuum degree is 0.25 Mpa. When the film is sequentially longitudinally stretched and transversely stretched by using stretching equipment, the ambient temperature is 290 ℃, and when the coating film is shaped, the ambient temperature is 320 ℃.
In the embodiment, the PI is used as the film base material, the second mixture of the silicon dioxide and the PI prepolymer is used as the heat-conducting filler, and the coating film prepared by the preparation method of the coating film has a high melting point, so that the coating film is not easy to shrink, and the thermal stability in the core bag is improved. Meanwhile, the coating film has a high heat conductivity coefficient, the heat dissipation efficiency of the coating film is improved, the heat accumulation in the core bag is reduced, the risk of thermal runaway of the core bag is reduced, and the stability and reliability of the core bag are improved.
The foregoing embodiments are merely illustrative of the principles and features of this invention, which is not limited to the above-described embodiments, but rather is susceptible to various changes and modifications without departing from the spirit and scope of the invention, which changes and modifications are within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (10)
1. A preparation method of a coating film is characterized by comprising the following steps:
s1: mixing a film base material with a melting point higher than 180 ℃ and a heat-conducting filler according to a first preset weight proportion to form a first mixture;
s2: stirring and heating the first mixture to pre-crystallize the first mixture;
s3: drying the pre-crystallized first mixture, and then performing melt extrusion to form a film;
s4: and stretching the film to form a coating film.
2. The method for preparing the coating film according to claim 1, wherein the first predetermined weight ratio is 1: (0.1-0.5).
3. The method for preparing the cover film according to claim 1, wherein the film base material is any one of PI, PP or PET.
4. The method for preparing the coating film according to claim 3, wherein the heat conductive filler is a second mixture obtained by mixing any one of silicon dioxide, aluminum oxide and silicon nitride with a prepolymer of the corresponding film base material in a second preset weight ratio, and the second preset weight ratio is 1: (1.5-3.5).
5. The method for preparing the cover film according to claim 1, wherein the step S4 includes:
s41: longitudinally stretching the film according to a preset longitudinal stretching proportion;
s42: and transversely stretching the film according to a preset transverse stretching ratio to form a coating film.
6. The method for producing a coating film according to claim 5, wherein the preset longitudinal stretching ratio and the preset transverse stretching ratio are 1: (3-5) and 1: (3-7).
7. The method for preparing the cover film according to claim 1, further comprising, after the step S4, the step S5: and winding and slitting the coating film.
8. The method according to claim 1, wherein the thermally conductive filler has a particle size of 20 μm or less.
9. A cover film for insulating and encapsulating a battery core pack, wherein the cover film is prepared by the method for preparing the cover film according to any one of claims 1 to 8.
10. A battery comprising the cover film according to claim 9.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113363614A (en) * | 2021-06-10 | 2021-09-07 | 东莞新能安科技有限公司 | Battery package and consumer |
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Application publication date: 20200714 |