CN116979154A - Composite pole piece, preparation method thereof, film-forming winding device and battery - Google Patents
Composite pole piece, preparation method thereof, film-forming winding device and battery Download PDFInfo
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- CN116979154A CN116979154A CN202310966228.5A CN202310966228A CN116979154A CN 116979154 A CN116979154 A CN 116979154A CN 202310966228 A CN202310966228 A CN 202310966228A CN 116979154 A CN116979154 A CN 116979154A
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- 239000002131 composite material Substances 0.000 title claims abstract description 72
- 238000004804 winding Methods 0.000 title claims abstract description 49
- 238000002360 preparation method Methods 0.000 title claims abstract description 19
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- 150000001875 compounds Chemical class 0.000 claims abstract description 5
- 239000012528 membrane Substances 0.000 claims description 31
- 238000005096 rolling process Methods 0.000 claims description 27
- 238000013329 compounding Methods 0.000 claims description 26
- 150000002484 inorganic compounds Chemical class 0.000 claims description 20
- 229910010272 inorganic material Inorganic materials 0.000 claims description 20
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- 238000007590 electrostatic spraying Methods 0.000 claims description 12
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 7
- 239000013543 active substance Substances 0.000 claims description 7
- 230000000712 assembly Effects 0.000 claims description 7
- 238000000429 assembly Methods 0.000 claims description 7
- 238000009704 powder extrusion Methods 0.000 claims description 7
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 6
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- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 6
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- 229910010271 silicon carbide Inorganic materials 0.000 claims description 4
- OQMIRQSWHKCKNJ-UHFFFAOYSA-N 1,1-difluoroethene;1,1,2,3,3,3-hexafluoroprop-1-ene Chemical group FC(F)=C.FC(F)=C(F)C(F)(F)F OQMIRQSWHKCKNJ-UHFFFAOYSA-N 0.000 claims description 3
- 229910052580 B4C Inorganic materials 0.000 claims description 3
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- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims description 3
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- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 3
- 239000004111 Potassium silicate Substances 0.000 claims description 3
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 3
- 239000004115 Sodium Silicate Substances 0.000 claims description 3
- 229920002125 Sokalan® Polymers 0.000 claims description 3
- 239000002174 Styrene-butadiene Substances 0.000 claims description 3
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 claims description 3
- ZQOBAJVOKBJPEE-UHFFFAOYSA-N [B].[C].[N].[Si] Chemical compound [B].[C].[N].[Si] ZQOBAJVOKBJPEE-UHFFFAOYSA-N 0.000 claims description 3
- YKTSYUJCYHOUJP-UHFFFAOYSA-N [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] Chemical compound [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] YKTSYUJCYHOUJP-UHFFFAOYSA-N 0.000 claims description 3
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 claims description 3
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 3
- 239000010425 asbestos Substances 0.000 claims description 3
- INAHAJYZKVIDIZ-UHFFFAOYSA-N boron carbide Chemical compound B12B3B4C32B41 INAHAJYZKVIDIZ-UHFFFAOYSA-N 0.000 claims description 3
- 239000000378 calcium silicate Substances 0.000 claims description 3
- 229910052918 calcium silicate Inorganic materials 0.000 claims description 3
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 claims description 3
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 3
- 229940081734 cellulose acetate phthalate Drugs 0.000 claims description 3
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 3
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- 239000001866 hydroxypropyl methyl cellulose Substances 0.000 claims description 3
- 229920003088 hydroxypropyl methyl cellulose Polymers 0.000 claims description 3
- 235000010979 hydroxypropyl methyl cellulose Nutrition 0.000 claims description 3
- UFVKGYZPFZQRLF-UHFFFAOYSA-N hydroxypropyl methyl cellulose Chemical compound OC1C(O)C(OC)OC(CO)C1OC1C(O)C(O)C(OC2C(C(O)C(OC3C(C(O)C(O)C(CO)O3)O)C(CO)O2)O)C(CO)O1 UFVKGYZPFZQRLF-UHFFFAOYSA-N 0.000 claims description 3
- 239000000395 magnesium oxide Substances 0.000 claims description 3
- UPKIHOQVIBBESY-UHFFFAOYSA-N magnesium;carbanide Chemical compound [CH3-].[CH3-].[Mg+2] UPKIHOQVIBBESY-UHFFFAOYSA-N 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 3
- 239000010445 mica Substances 0.000 claims description 3
- 229910052618 mica group Inorganic materials 0.000 claims description 3
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- 229920001495 poly(sodium acrylate) polymer Polymers 0.000 claims description 3
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- 229920006393 polyether sulfone Polymers 0.000 claims description 3
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- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 3
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 claims description 3
- 229910052913 potassium silicate Inorganic materials 0.000 claims description 3
- 235000019353 potassium silicate Nutrition 0.000 claims description 3
- 239000002994 raw material Substances 0.000 claims description 3
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- 229910052895 riebeckite Inorganic materials 0.000 claims description 3
- 239000000377 silicon dioxide 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
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 claims description 3
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 claims description 3
- NNMHYFLPFNGQFZ-UHFFFAOYSA-M sodium polyacrylate Chemical compound [Na+].[O-]C(=O)C=C NNMHYFLPFNGQFZ-UHFFFAOYSA-M 0.000 claims description 3
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052911 sodium silicate Inorganic materials 0.000 claims description 3
- 239000004695 Polyether sulfone Substances 0.000 claims description 2
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- 238000007599 discharging Methods 0.000 description 4
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 3
- 229910001416 lithium ion Inorganic materials 0.000 description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
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- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910021385 hard carbon Inorganic materials 0.000 description 1
- DCYOBGZUOMKFPA-UHFFFAOYSA-N iron(2+);iron(3+);octadecacyanide Chemical class [Fe+2].[Fe+2].[Fe+2].[Fe+3].[Fe+3].[Fe+3].[Fe+3].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] DCYOBGZUOMKFPA-UHFFFAOYSA-N 0.000 description 1
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- 239000002699 waste material Substances 0.000 description 1
- 230000037303 wrinkles Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
- H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
-
- 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
- H01M10/04—Construction or manufacture in general
- H01M10/0468—Compression means for stacks of electrodes and separators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Cell Separators (AREA)
Abstract
In order to solve the problems of frequent winding and unwinding, low integration degree, wide equipment occupation area and high production energy consumption in the preparation process of a winding core in the prior art, the invention provides a composite pole piece, a preparation method thereof, a film forming winding device and a battery, wherein the composite pole piece comprises a first pole piece, a first insulating film, a second pole piece and a second insulating film which are sequentially arranged, and the first insulating film is respectively in thermal composite connection with the first pole piece and the second pole piece; and one side of the second insulating film, which is away from the first insulating film, is in thermal compound connection.
Description
Technical Field
The invention belongs to the technical field of battery pole pieces, and particularly relates to a composite pole piece, a preparation method thereof, a film forming winding device and a battery.
Background
The structure of the current lithium ion battery mainly comprises a positive plate and a negative plate, wherein the positive plate and the negative plate are separated by a diaphragm at intervals. The diaphragm is an important component of the current lithium ion battery, is a polymer functional material with a nanoscale microporous structure, and has the main functions of separating the anode and the cathode of the battery, absorbing electrolyte, only allowing lithium ions to pass through and not allowing electrons to pass through. And the separator occupies a large amount of space inside the electrochemical device, playing a critical role in safety.
The preparation method of the battery cell in the prior art is that the positive plate, the negative plate and the diaphragm are respectively unreeled on a winding machine, are sequentially put into a winding needle and are wound into the battery cell, and the battery cell is influenced by the state of the plate and the precision of equipment, needs frequent machine adjustment, and easily causes the problems of wrinkling of the plate and the diaphragm, poor uniformity and the like.
Disclosure of Invention
Aiming at the problems of frequent winding and unwinding, low integration degree, wide equipment occupation area and high production energy consumption in the preparation process of the winding core in the prior art, the invention provides a composite pole piece and a preparation method thereof, film-forming winding and a battery.
The technical scheme adopted by the invention for solving the technical problems is as follows:
in one aspect, the invention provides a composite pole piece, which comprises a first pole piece, a first insulating membrane, a second pole piece and a second insulating membrane which are sequentially arranged, wherein the first insulating membrane is respectively in thermal composite connection with the first pole piece and the second pole piece; and one side of the second insulating film, which is away from the first insulating film, is in thermal compound connection.
According to the invention, the first pole piece, the first insulating film, the second pole piece and the second insulating film are thermally compounded to form the composite film, so that the problems of easiness in wrinkling and poor uniformity of the pole piece and the diaphragm are avoided when the composite film is wound to form the winding core, and meanwhile, the structure of the composite film cancels the feeding and discharging mechanisms of the first pole piece, the second pole piece and the diaphragm, reduces the rubberizing mechanism, and greatly improves the winding efficiency. The first insulating film and the second insulating film replace the diaphragm in the original battery cell, so that the energy density is improved.
Optionally, the thickness of the first insulating film is 3-50 μm, and the porosity of the first insulating film is 5-60%; the thickness of the second insulating film is 3-50 mu m, and the porosity of the second insulating film is 5-60%.
Optionally, the first insulating film and the second insulating film respectively include a fibrous inorganic compound and a binder.
Optionally, the first insulating film and the second insulating film respectively include the following parts by weight: 70-99 parts of fibrous inorganic compound and 1-30 parts of binder.
Optionally, the fibrous inorganic compound comprises one or more of glass fiber, mica, sodium silicate, bastnaesite, alumina, silica, zirconia, magnesia, silicon nitride, aluminum nitride, titanium nitride, boron nitride, aluminum silicate, calcium silicate, potassium silicate, silicon carbide, boron carbide, magnesium carbide, silicon boron carbon nitrogen, mullite, and asbestos;
the binder includes one or more of polyvinylidene fluoride, a copolymer of vinylidene fluoride-hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, styrene butadiene rubber, polyethersulfone, polyimide, polyethylene terephthalate, styrene-butadiene rubber, styrene-butyl acrylate copolymer, acrylic modified SBR resin, styrene- (meth) acrylate copolymer, polyvinyl alcohol, sodium polyacrylate, polyvinylidene fluoride, polyamide, polyimide, chitosan, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, vinyl acetate copolymer, cellulose acetate phthalate, and hydroxypropyl methylcellulose.
Optionally, the first pole piece comprises a first current collector and a first electrode membrane, and the thickness of the first electrode membrane is 0.05-0.55mm; the second electrode sheet comprises a second current collector and a second electrode film, and the thickness of the second electrode film is 0.05-0.55mm.
On the other hand, the invention provides a preparation method of the composite pole piece, which comprises the following steps:
acquiring a first pole piece, a first insulating film, a second pole piece and a second insulating film;
and sequentially stacking the first pole piece, the first insulating film, the second pole piece and the second insulating film into a roll gap, and obtaining the composite pole piece through thermal compounding.
According to the invention, the first pole piece, the first insulating film, the second pole piece and the second insulating film are thermally compounded to form the composite film, so that the feeding and discharging mechanisms of the first pole piece, the second pole piece and the diaphragm in the existing battery cell production are eliminated, the rubberizing mechanism is reduced, and the winding efficiency is greatly improved.
Optionally, the preparation methods of the first insulating film and the second insulating film both comprise the steps of mixing a fibrous inorganic compound with a binder, and obtaining the first insulating film or the second insulating film through powder extrusion or electrostatic spraying;
the preparation method of the first pole piece comprises the steps of extruding or electrostatic spraying a first active substance through powder to obtain a first electrode membrane, and thermally compounding the first electrode membrane with a first current collector to obtain the first pole piece; or, the first active material solution is coated on the first current collector to obtain the first pole piece;
the preparation method of the second pole piece comprises the steps of extruding or electrostatic spraying second active substances through powder to obtain a second electrode membrane, and thermally compounding the second electrode membrane with a second current collector to obtain the second pole piece; or the second active material solution is coated on the second current collector to obtain the second pole piece.
Optionally, the thermal compounding temperature is 70-200 ℃.
On the other hand, the invention provides a film-forming winding device of the composite pole piece, which comprises the following components:
the material boxes are respectively used for placing raw materials for preparing the first insulating film, the second insulating film and the electrode film, and the electrode film comprises a first electrode film and a second electrode film;
the calendaring roller assemblies are arranged below the feed box in a one-to-one correspondence manner and used for extruding powder into a film;
the two winding rollers are used for winding and unwinding current collectors, and the current collectors comprise a first current collector and a second current collector;
two first rolling assemblies for roll-thermally compounding the electrode membrane and the current collector;
the second rolling assembly is used for rolling and thermally compounding the second pole piece and the first insulating film;
the third rolling assembly and the winding needle are used for receiving the second rolling assembly, the second insulating film and the first pole piece, and rolling, heating and compounding the materials to prepare the composite pole piece; the winding needle is used for winding the composite pole piece into an electric core.
In another aspect, the invention provides a battery, comprising a battery core, wherein the battery core is formed by winding the composite pole piece described in any one of the above, or the battery core is prepared by a film-forming winding device of the composite pole piece.
Drawings
FIG. 1 is a schematic view of a composite pole piece according to an embodiment of the present invention;
FIG. 2 is an electron microscope view of a first insulating film of a composite pole piece according to an embodiment of the present invention;
FIG. 3 is a schematic structural view of a film-forming winding device for a composite pole piece according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a film forming and winding device for a composite pole piece according to an embodiment of the present invention.
Reference numerals in the drawings of the specification are as follows:
1. a first pole piece; 2. a first insulating film; 3. a second pole piece; 4. a second insulating film; 5. a feed box; 6. a calender roll assembly; 7. a roller; 8. a first roll-in assembly; 9. a second roll-in assembly; 10. a third roll-in assembly; 11. tension roller.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects solved by the invention more clear, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
An embodiment of the invention provides a composite pole piece, which comprises a first pole piece 1, a first insulating film 2, a second pole piece 3 and a second insulating film 4 which are sequentially arranged, wherein the first insulating film 2 is in thermal composite connection with the first pole piece 1 and the second pole piece 3 respectively. The second insulating film 4 is in thermal compound connection with one side of the second pole piece 3 facing away from the first insulating film 2. Specifically, the first pole piece 1 is a positive pole piece, the second pole piece 3 is a negative pole piece, or the first pole piece 1 is a negative pole piece, and the second pole piece 3 is a positive pole piece.
According to the invention, the first pole piece 1, the first insulating film 2, the second pole piece 3 and the second insulating film 4 are thermally compounded to form the composite film, so that the problem that the pole piece and the diaphragm are easy to wrinkle and poor in uniformity is avoided when the composite film is wound to form a winding core, and meanwhile, the structure of the composite film cancels the feeding and discharging mechanisms of the first pole piece 1, the second pole piece 3 and the diaphragm, reduces the rubberizing mechanism, and greatly improves the winding efficiency. The first insulating film 2 and the second insulating film 4 replace the diaphragms in the original battery cell, so that the energy density is improved.
In some embodiments, the thickness of the first insulating film 2 is 3-50 μm, and the porosity of the first insulating film 2 is 5-60%. The thickness of the second insulating film 4 is 3-50 μm, and the porosity of the second insulating film 4 is 5-60%.
In a preferred embodiment, the thickness of the first insulating film 2 is 11-13 μm, and the porosity of the first insulating film 2 is 35-50%. The thickness of the second insulating film 4 is 11-13 μm, and the porosity of the second insulating film 4 is 35-50%.
In some embodiments, the first insulating film 2 and the second insulating film 4 each include the following parts by weight: 70-99 parts of fibrous inorganic compound and 1-30 parts of binder.
In some embodiments, the first insulating film sheet 2 and the second insulating film sheet 4 each include a fibrous inorganic compound and a binder. The first insulating film 2 and the second insulating film 4 replace the polymer-based diaphragms commonly used in the prior art, and the fibrous inorganic compound enables the first insulating film 2 and the second insulating film 4 to have the functions of electronic insulation and ion conduction, and simultaneously have excellent thermal and mechanical properties.
In some embodiments, the fibrous inorganic compound comprises one or more of glass fibers, mica, sodium silicate, bastnaesite, alumina, silica, zirconia, magnesia, silicon nitride, aluminum nitride, titanium nitride, boron nitride, aluminum silicate, calcium silicate, potassium silicate, silicon carbide, boron carbide, magnesium carbide, silicon boron carbon nitrogen, mullite, and asbestos.
In some embodiments, the binder comprises one or more of polyvinylidene fluoride, copolymers of vinylidene fluoride-hexafluoropropylene, polyamides, polyacrylonitrile, polyacrylates, polyacrylic acids, polyacrylates, sodium carboxymethyl cellulose, polyvinylpyrrolidone, polyvinyl ethers, polymethyl methacrylates, polytetrafluoroethylene, polyhexafluoropropylene, styrene-butadiene rubber, polyethersulfones, polyimides, polyethylene terephthalate, styrene-butadiene rubber, styrene-butyl acrylate copolymers, acrylic modified SBR resins, styrene- (meth) acrylate copolymers, polyvinyl alcohol, sodium polyacrylate, polyvinylidene fluoride, polyamides, polyimides, chitosan, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, vinyl acetate copolymers, cellulose acetate phthalate, and hydroxypropyl methylcellulose.
In some embodiments, the first pole piece 1 comprises a first current collector and a first electrode membrane, and the thickness of the first electrode membrane is 0.05-0.55mm. The second electrode sheet 3 comprises a second current collector and a second electrode film, and the thickness of the second electrode film is 0.05-0.55mm.
On the other hand, an embodiment of the invention provides a preparation method of the composite pole piece, which comprises the following steps:
a first electrode sheet 1, a first insulating film sheet 2, a second electrode sheet 3, and a second insulating film sheet 4 are obtained.
And sequentially stacking the first pole piece 1, the first insulating film 2, the second pole piece 3 and the second insulating film 4 into a roll gap, and obtaining the composite pole piece through thermal compounding. Specifically, the rolling pressure can be adjusted according to the thickness of the composite pole piece, so that the first pole piece 1, the first insulating film 2, the second pole piece 3 and the second insulating film 4 are fully bonded.
According to the invention, the first pole piece 1, the first insulating film 2, the second pole piece 3 and the second insulating film 4 are thermally compounded to form the composite film, so that the feeding and discharging mechanisms of the first pole piece 1, the second pole piece 3 and the diaphragm in the conventional cell production are omitted, the rubberizing mechanism is reduced, and the winding efficiency is greatly improved.
In some embodiments, the preparation method of the first insulating film 2 and the second insulating film 4 includes mixing a fibrous inorganic compound with a binder, and obtaining the first insulating film 2 or the second insulating film 4 by powder extrusion or electrostatic spraying.
The preparation method of the first pole piece 1 comprises the steps of obtaining a first electrode membrane by powder extrusion or electrostatic spraying of a first active substance, and then thermally compounding the first electrode membrane with a first current collector to obtain the first pole piece 1. Or, the first active material solution is coated on the first current collector to obtain the first pole piece 1.
The preparation method of the second pole piece 3 comprises the steps of extruding or electrostatic spraying second active substances through powder to obtain a second electrode membrane, and thermally compounding the second electrode membrane with a second current collector to obtain the second pole piece 3. Or, the second active material solution is coated on the second current collector to obtain the second electrode sheet 3. The first insulating film sheet 2, the second insulating film sheet 4 are prepared by a dry method. The first pole piece 1 and the second pole piece 3 avoid generating harmful waste materials, are environment-friendly and save cost.
Specifically, the first active material includes one or more of a layered oxide of lithium or sodium, a polyanion compound, and a prussian blue analog, and the second active material includes one or more of graphite, hard carbon, silicon carbide, silicon oxide, and metallic lithium.
In some embodiments, the thermal compounding temperature is 70-200 ℃, preferably, the thermal compounding temperature is 95-120 ℃.
In some embodiments, the composite pole piece has a thickness of 0.1-1mm.
An embodiment of the present invention provides a film forming and winding device for a composite pole piece, including:
a plurality of feed boxes 5 for respectively placing raw materials for preparing the first insulating film 2, the second insulating film 4 and the electrode film, wherein the electrode film comprises a first electrode film and a second electrode film;
the calendaring roller assemblies 6 are respectively arranged below the feed box 5 in a one-to-one correspondence manner and are used for extruding powder into a film;
two winding rollers 7 for winding and unwinding current collectors, which include a first current collector and a second current collector;
two first rolling assemblies 8 for roll-thermally compounding the electrode membrane and the current collector;
a second roll-in unit 9 for roll-in heat-compounding the second electrode sheet 3 and the first insulating film sheet 2;
and the third rolling assembly 10 and a winding needle (not shown in the figure) are used for receiving the second rolling assembly 9, the second insulating film 4 and the first pole piece 1, and rolling, heating and compounding to prepare the composite pole piece. The winding needle is used for winding the composite pole piece into an electric core.
Specifically, a plurality of tensioning rollers 11 are further included for tensioning the first insulating film sheet 2, the second insulating film sheet 4, the current collector, the second pole piece 3, the first pole piece 1, and the composite pole piece.
In this embodiment, the first pole piece 1, the first insulating film 2, the second pole piece 3 and the second insulating film 4 of the composite pole piece are integrally arranged from film formation to winding production, and compared with the existing production mode, the winding between devices is canceled, so that the production efficiency is greatly improved, and the cost is saved.
The working process of the film forming and winding device of the composite pole piece of the embodiment is as follows: the material boxes 5 are discharged, the powder is extruded by the first calendaring roller assemblies 6 respectively to prepare a first insulating film 2, a second insulating film 4, a first electrode film and a second electrode film, the first electrode film and a first current collector enter a first rolling assembly 8, and the first electrode film and the first current collector are thermally compounded to obtain the first pole piece 1. The second electrode film sheet and the second current collector enter another first rolling assembly 8 to be thermally compounded to obtain a second electrode sheet 3. The second electrode sheet 3 and the first insulating film sheet 2 enter a second rolling assembly 9 for thermal compounding and then enter a third rolling assembly 10, meanwhile, the second insulating film sheet 4 and the first electrode film sheet 1 are connected into a roll gap of the third rolling assembly 10 for rolling thermal compounding to obtain a composite electrode sheet, and the composite electrode sheet is put into a winding needle after being tensioned by a tensioning roller and is wound into an electric core by the winding needle.
In another embodiment of the present invention, as shown in fig. 4, the first electrode sheet 1 may be coated on two sides or one side of the first current collector with slurry of the first active material and then dried to prepare the first electrode sheet, the second electrode sheet 3 may be coated on two sides or one side of the second current collector with slurry of the second active material and then dried to prepare the second electrode sheet 3, the second electrode sheet 3 and the first insulating film 2 are thermally compounded by the second rolling assembly 9 and then enter the third rolling assembly 10, meanwhile, the second insulating film 4 and the first electrode film 1 are connected into a roll gap of the third rolling assembly 10 and are thermally compounded by rolling to obtain a composite electrode sheet, and the composite electrode sheet is tensioned by a tensioning roller and then put into a winding needle to be wound into an electrical core by the winding needle.
An embodiment of the invention provides a battery, which comprises an electric core, wherein the electric core is formed by winding the composite pole piece described in any one of the above, or is prepared by a film-forming winding device of the composite pole piece.
The invention is further illustrated by the following examples.
Example 1
The embodiment is used for explaining the composite pole piece disclosed by the invention, and comprises the following operation steps: and (3) carrying out powder extrusion or electrostatic spraying on the first active substance to obtain a first electrode membrane, and then thermally compounding the first electrode membrane and a first current collector to obtain the first pole piece 1, wherein the thickness of the first pole piece 1 is 0.18mm.
And (3) performing powder extrusion or electrostatic spraying on the second active material to obtain a second electrode membrane, and thermally compounding the second electrode membrane and a second current collector to obtain the second electrode sheet 3, wherein the thickness of the second electrode sheet 3 is 0.16mm. .
93 parts of glass fiber and 7 parts of polytetrafluoroethylene are subjected to powder extrusion or electrostatic spraying to obtain a first insulating film sheet 2 and the second insulating film sheet 4. The thickness of the first insulating film 2 and the second insulating film 4 were 13 μm and the porosity was 40%, respectively.
The first pole piece 1, the first insulating film 2, the second pole piece 3 and the second insulating film 4 are sequentially stacked into a roll gap, and the composite pole piece is obtained through thermal compounding at 110 ℃.
Example 2
The present embodiment is used for illustrating the composite pole piece disclosed in the present invention, and includes most of the operation steps in embodiment 1, which are different in that: 75 parts of fibrous inorganic compound.
Example 3
The present embodiment is used for illustrating the composite pole piece disclosed in the present invention, and includes most of the operation steps in embodiment 1, which are different in that: 80 parts of fibrous inorganic compound.
Example 4
The present embodiment is used for illustrating the composite pole piece disclosed in the present invention, and includes most of the operation steps in embodiment 1, which are different in that: 85 parts of fibrous inorganic compound.
Example 5
The present embodiment is used for illustrating the composite pole piece disclosed in the present invention, and includes most of the operation steps in embodiment 1, which are different in that: 97 parts of fibrous inorganic compound.
Example 6
The present embodiment is used for illustrating the composite pole piece disclosed in the present invention, and includes most of the operation steps in embodiment 1, which are different in that: the thickness of the first insulating film 2 and the second insulating film 4 were 25 μm and the porosity was 55%, respectively.
Example 7
The present embodiment is used for illustrating the composite pole piece disclosed in the present invention, and includes most of the operation steps in embodiment 1, which are different in that: the thickness of the first insulating film 2 and the second insulating film 4 were 18 μm and the porosity was 50%, respectively.
Example 8
The present embodiment is used for illustrating the composite pole piece disclosed in the present invention, and includes most of the operation steps in embodiment 1, which are different in that: the thickness of the first insulating film 2 and the second insulating film 4 were 11 μm and the porosity was 35%, respectively.
Example 9
The present embodiment is used for illustrating the composite pole piece disclosed in the present invention, and includes most of the operation steps in embodiment 1, which are different in that: the thickness of the first insulating film 2 and the second insulating film 4 were 5 μm and the porosity was 25%, respectively.
Comparative example 1
The present embodiment is used for illustrating the composite pole piece disclosed in the present invention, and includes most of the operation steps in embodiment 1, which are different in that: the first insulating film 2 is respectively bonded with the first pole piece 1 and the second pole piece 3, and the second insulating film 4 is bonded with one side of the second pole piece 3 away from the first insulating film 2.
Comparative example 2
The present embodiment is used for illustrating the composite pole piece disclosed in the present invention, and includes most of the operation steps in embodiment 1, which are different in that: the first pole piece 1, the first insulating film 2, the second pole piece 3 and the second insulating film 4 are stacked in order.
Performance testing
The battery cells prepared in examples and comparative examples were assembled into a battery, and the performance of the battery was tested, and the test results are shown in table 1.
Test 1: the 25 ℃ cycle was tested with 1C charge and discharge, the discharge capacities of the battery at the third and 700 weeks of 25 ℃ cycle charge and discharge were recorded and calculated according to the following formula: week 700/week 3 x 100%.
Test 2: the 45 ℃ cycle was tested with 1C charge and discharge, the discharge capacities of the battery at the third and 500 weeks of 45 ℃ cycle charge and discharge were recorded, and calculated according to the following formula: week 500 capacity/week 3 capacity x 100%.
The test results are shown in Table 1.
TABLE 1
As is clear from examples 2 to 5, the first insulating film and the second insulating film were excellent in cycle performance at a mass ratio of the fibrous inorganic compound of 85% or more, but when the content was too high (about 96% or more), the binder content in the first insulating film and the second insulating film was relatively insufficient, and the retention rate was lowered due to insufficient adhesion in the latter cycle. As the content of the fibrous inorganic compound decreases, the retention rate decreases after circulation, and at the same time, local micro-short circuit is more likely to occur after vibration, and the capacity retention rate decreases sharply. As the content of the fibrous inorganic compound increases, the insulation property increases, and the capacity retention after vibration increases. As is clear from the test results of examples 6 to 9, as the porosity of the insulating film increases, the ion conductivity increases, and the cycle retention rate increases slightly, but after vibration, a slight short circuit is easily generated due to dropping, and the retention rate decreases. The comparative examples 1 and 2 did not heat or directly stack the pole pieces, which could make the bonding between the pole pieces unstable, and the pole pieces were separated after cyclic expansion or vibration test, resulting in sharp capacity reduction or even complete disconnection.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (10)
1. The composite pole piece is characterized by comprising a first pole piece, a first insulating membrane, a second pole piece and a second insulating membrane which are sequentially arranged, wherein the first insulating membrane is in thermal composite connection with the first pole piece and the second pole piece respectively; and one side of the second insulating film, which is away from the first insulating film, is in thermal compound connection.
2. The composite pole piece of claim 1, wherein the first insulating film has a thickness of 3-50 μm and a porosity of 5-60%; the thickness of the second insulating film is 3-50 mu m, and the porosity of the second insulating film is 5-60%.
3. The composite pole piece of claim 1, wherein the first and second insulating films each comprise a fibrous inorganic compound and a binder.
4. A composite pole piece according to claim 3, wherein the first and second insulating films each comprise the following parts by weight: 70-99 parts of fibrous inorganic compound and 1-30 parts of binder.
5. A composite pole piece according to claim 3, wherein the fibrous inorganic compound comprises one or more of glass fibers, mica, sodium silicate, bastnaesite, alumina, silica, zirconia, magnesia, silicon nitride, aluminum nitride, titanium nitride, boron nitride, aluminum silicate, calcium silicate, potassium silicate, silicon carbide, boron carbide, magnesium carbide, silicon boron carbon nitrogen, mullite, and asbestos;
the binder includes one or more of polyvinylidene fluoride, a copolymer of vinylidene fluoride-hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, styrene butadiene rubber, polyethersulfone, polyimide, polyethylene terephthalate, styrene-butadiene rubber, styrene-butyl acrylate copolymer, acrylic modified SBR resin, styrene- (meth) acrylate copolymer, polyvinyl alcohol, sodium polyacrylate, polyvinylidene fluoride, polyamide, polyimide, chitosan, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, vinyl acetate copolymer, cellulose acetate phthalate, and hydroxypropyl methylcellulose.
6. The composite pole piece of claim 1, wherein the first pole piece comprises a first current collector and a first electrode membrane, the first electrode membrane having a thickness of 0.05-0.55mm; the second electrode sheet comprises a second current collector and a second electrode film, and the thickness of the second electrode film is 0.05-0.55mm.
7. A method of making a composite pole piece according to claims 1-6, comprising the steps of:
acquiring a first pole piece, a first insulating film, a second pole piece and a second insulating film;
and sequentially stacking the first pole piece, the first insulating film, the second pole piece and the second insulating film into a roll gap, and obtaining the composite pole piece through thermal compounding.
8. The method according to claim 7, wherein,
the preparation method of the first insulating film and the second insulating film comprises the steps of mixing fibrous inorganic compounds with binders, and obtaining the first insulating film or the second insulating film through powder extrusion or electrostatic spraying;
the preparation method of the first pole piece comprises the steps of extruding or electrostatic spraying a first active substance through powder to obtain a first electrode membrane, and thermally compounding the first electrode membrane with a first current collector to obtain the first pole piece; or, the first active material solution is coated on the first current collector to obtain the first pole piece;
the preparation method of the second pole piece comprises the steps of extruding or electrostatic spraying second active substances through powder to obtain a second electrode membrane, and thermally compounding the second electrode membrane with a second current collector to obtain the second pole piece; or the second active material solution is coated on the second current collector to obtain the second pole piece.
9. A film-forming winding device of the composite pole piece according to claims 1 to 6, comprising:
the material boxes are respectively used for placing raw materials for preparing the first insulating film, the second insulating film and the electrode film, and the electrode film comprises a first electrode film and a second electrode film;
the calendaring roller assemblies are arranged below the feed box in a one-to-one correspondence manner and used for extruding powder into a film;
the two winding rollers are used for winding and unwinding current collectors, and the current collectors comprise a first current collector and a second current collector;
two first rolling assemblies for roll-thermally compounding the electrode membrane and the current collector;
the second rolling assembly is used for rolling and thermally compounding the second pole piece and the first insulating film;
the third rolling assembly and the winding needle are used for receiving the second rolling assembly, the second insulating film and the first pole piece, and rolling, heating and compounding the materials to prepare the composite pole piece; the winding needle is used for winding the composite pole piece into an electric core.
10. A battery comprising a cell wound from the composite pole piece of any one of claims 1-8, or prepared from the film-forming winding device of the composite pole piece of claim 9.
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| CN202310966228.5A CN116979154A (en) | 2023-08-02 | 2023-08-02 | Composite pole piece, preparation method thereof, film-forming winding device and battery |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310966228.5A CN116979154A (en) | 2023-08-02 | 2023-08-02 | Composite pole piece, preparation method thereof, film-forming winding device and battery |
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