CN114284642B - Multilayer coating diaphragm and polymer battery prepared from same - Google Patents
Multilayer coating diaphragm and polymer battery prepared from same Download PDFInfo
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- CN114284642B CN114284642B CN202111407755.XA CN202111407755A CN114284642B CN 114284642 B CN114284642 B CN 114284642B CN 202111407755 A CN202111407755 A CN 202111407755A CN 114284642 B CN114284642 B CN 114284642B
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- 238000000576 coating method Methods 0.000 title claims abstract description 190
- 239000011248 coating agent Substances 0.000 title claims abstract description 186
- 229920000642 polymer Polymers 0.000 title claims abstract description 137
- 239000000758 substrate Substances 0.000 claims abstract description 30
- 239000003792 electrolyte Substances 0.000 claims abstract description 28
- 230000008961 swelling Effects 0.000 claims abstract description 22
- 239000012528 membrane Substances 0.000 claims description 29
- 229920005596 polymer binder Polymers 0.000 claims description 21
- 239000002491 polymer binding agent Substances 0.000 claims description 21
- 239000002002 slurry Substances 0.000 claims description 16
- 229910010272 inorganic material Inorganic materials 0.000 claims description 14
- 239000011147 inorganic material Substances 0.000 claims description 14
- 230000015572 biosynthetic process Effects 0.000 claims description 12
- 239000002131 composite material Substances 0.000 claims description 10
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 9
- 229910052782 aluminium Inorganic materials 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 9
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 8
- 229910001593 boehmite Inorganic materials 0.000 claims description 8
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 claims description 8
- 229920000120 polyethyl acrylate Polymers 0.000 claims description 8
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 8
- 239000002033 PVDF binder Substances 0.000 claims description 7
- 239000003960 organic solvent Substances 0.000 claims description 7
- 239000002985 plastic film Substances 0.000 claims description 7
- 229920006255 plastic film Polymers 0.000 claims description 7
- 238000007731 hot pressing Methods 0.000 claims description 6
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 claims description 5
- 239000000347 magnesium hydroxide Substances 0.000 claims description 5
- 229910001862 magnesium hydroxide Inorganic materials 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 4
- 239000011268 mixed slurry Substances 0.000 claims description 4
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 4
- 238000004806 packaging method and process Methods 0.000 claims description 4
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 4
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 4
- 239000000377 silicon dioxide Substances 0.000 claims description 4
- 230000009471 action Effects 0.000 claims description 3
- 238000007872 degassing Methods 0.000 claims description 3
- 238000011049 filling Methods 0.000 claims description 3
- 238000004804 winding Methods 0.000 claims description 3
- 239000001913 cellulose Substances 0.000 claims description 2
- 229920002678 cellulose Polymers 0.000 claims description 2
- 229920000840 ethylene tetrafluoroethylene copolymer Polymers 0.000 claims description 2
- 229920003229 poly(methyl methacrylate) Polymers 0.000 claims description 2
- 229920002239 polyacrylonitrile Polymers 0.000 claims description 2
- 239000004926 polymethyl methacrylate Substances 0.000 claims description 2
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- 235000012239 silicon dioxide Nutrition 0.000 claims description 2
- 230000014759 maintenance of location Effects 0.000 abstract description 18
- 239000000853 adhesive Substances 0.000 abstract description 4
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- 238000012360 testing method Methods 0.000 description 10
- 239000000499 gel Substances 0.000 description 5
- 238000010521 absorption reaction Methods 0.000 description 4
- 239000011247 coating layer Substances 0.000 description 4
- 238000007599 discharging Methods 0.000 description 4
- 239000011244 liquid electrolyte Substances 0.000 description 4
- 230000035699 permeability Effects 0.000 description 4
- 238000013329 compounding Methods 0.000 description 3
- 230000008595 infiltration Effects 0.000 description 3
- 238000001764 infiltration Methods 0.000 description 3
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- 238000007756 gravure coating Methods 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 229910001410 inorganic ion Inorganic materials 0.000 description 2
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- 238000005303 weighing Methods 0.000 description 2
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- 238000004026 adhesive bonding Methods 0.000 description 1
- 239000002998 adhesive polymer Substances 0.000 description 1
- SNAAJJQQZSMGQD-UHFFFAOYSA-N aluminum magnesium Chemical compound [Mg].[Al] SNAAJJQQZSMGQD-UHFFFAOYSA-N 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000005524 ceramic coating Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
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- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
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- 239000000741 silica gel Substances 0.000 description 1
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Classifications
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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Abstract
The invention discloses a multilayer coating diaphragm and a polymer battery prepared by the same, wherein the diaphragm comprises a diaphragm substrate and a multilayer polymer coating coated on the diaphragm substrate; the multi-layer polymeric coating comprises a low swell ratio polymeric coating and a high swell ratio polymeric coating; the polymer coating with low swelling rate is uniformly coated on the surface of the diaphragm substrate; the Gao Rongzhang rate polymer coating is applied over the low-swell rate polymer coating at intervals. Compared with the existing diaphragm, in the design of the multi-layer coating diaphragm, the low-swelling rate polymer coating can improve the mechanical strength of the diaphragm and ensure the cohesiveness between the diaphragm and the electrode; the high-swelling-ratio polymer coating can improve the electrolyte retention in the battery, and the electrolyte retention is mutually supplemented through different effects of the coatings, so that the wettability of the adhesive coating diaphragm is greatly improved, the cohesiveness between an electrode and the diaphragm is enhanced, the interface consistency is ensured, and the electrochemical performance and the safety performance of the battery are improved.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a multilayer coating diaphragm and a polymer battery prepared from the multilayer coating diaphragm.
Background
As the popularity of electric vehicles increases year by year, the power battery industry also rapidly develops, and the battery demand for high energy density, which is compatible with safety, increases. In each part of the battery, the performance of the diaphragm material plays a critical role in improving the stability and safety of the battery, and the diaphragm with various coating layers on the surface and the diaphragm and pole piece thermal composite process are used to improve the energy density of the battery, so that the direction of optimizing the stability and safety of the battery interface is also a research hot spot of the industry.
CN111755648a was coated with an asymmetric coating on the separator, comprising at least one inorganic ion conductor layer coated on one side of the base film, and at least one organic polymer layer coated on the other side of the base film. The inorganic ion conductor functional layer and the organic polymer functional layer which are asymmetrically coated on the two sides of the base film can reduce the interface impedance between the diaphragm and the electrode, and improve the thermal stability, the liquid absorption rate, the ion conductivity and other characteristics of the diaphragm. CN212230512U is provided with three-layer coating on the diaphragm, the third coating with the substrate layer is connected, the second coating is the heat insulation gel layer. Through the superposition setting of three-layer coating for the liquid absorption performance and the liquid retention performance of diaphragm all improve to some extent. The CN107611314A is coated with a first coating and a second coating of adhesive polymer on two sides of the diaphragm respectively, and the lithium ion battery can meet the requirements on hardness and dynamic characteristics by carrying out different diaphragm coating designs on the anode and the cathode. The CN112952296A diaphragm is composed of a composite base film and a conductive ceramic coating, wherein the composite base film is prepared by mixing polyolefin and first conductive ceramic, and the ion conductivity is improved by constructing a conductive network. Although the porosity and the liquid absorption capacity of the battery can be improved to a certain extent, the functional coating can slow down the electrolyte infiltration rate of the battery cell, influence the consistency and the stability of the interface of the battery cell, and have no improvement on the safety performance under the condition of puncture damage such as needling and other internal short circuits, and the preparation process is more complicated and the cost is higher.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a multilayer coating diaphragm and a polymer battery prepared by the same, wherein the low-swelling polymer coating can improve the mechanical strength of the diaphragm and ensure the cohesiveness between the diaphragm and an electrode; the polymer coating with high swelling rate can improve the electrolyte retention in the battery, and through the different effects of the coatings, the electrolyte retention is mutually supplemented, so that the infiltration capacity of the adhesive coating diaphragm is greatly improved, the cohesiveness between an electrode and the diaphragm is enhanced, the interface consistency is ensured, free electrolyte is not contained in the prepared polymer battery, the risk of corroding an aluminum plastic film and leakage of liquid electrolyte is greatly reduced, and the electrochemical performance and the safety performance of the battery are improved. The interval coating makes the whole gluing amount of the diaphragm less than that of the uniform coating design, and reduces the production cost.
In order to achieve the above object, a first aspect of the present invention provides a multilayer coated separator comprising a separator substrate and a multilayer polymer coating layer coated on the separator substrate; the multi-layer polymeric coating comprises a low swell ratio polymeric coating and a high swell ratio polymeric coating; the polymer coating with low swelling rate is uniformly coated on the surface of the diaphragm substrate; the Gao Rongzhang rate polymer coating is applied over the low-swell rate polymer coating at intervals.
A second aspect of the invention provides a polymer battery comprising positive and negative electrodes and a separator, the separator being the multilayer coated separator.
A third aspect of the present invention provides a method for producing a polymer battery, comprising:
(1) Uniformly coating the slurry of the low-swelling polymer coating on the surface of the membrane substrate by adopting a gravure coating mode, and coating the slurry of the high-swelling polymer coating on the surface of the membrane substrate at stripe oblique line intervals to prepare a multi-layer coating membrane;
(2) Orderly stacking or winding a certain number of positive and negative plates and the multilayer coating diaphragm, and packaging the positive and negative plates and the multilayer coating diaphragm into a polymer battery by using an aluminum plastic film;
(3) Placing the battery into a pressure formation cabinet for heating and pressure formation after filling the battery, swelling the coating of the multilayer coating diaphragm, and firmly combining with the pole piece under the action of pressure;
(4) And connecting the battery after hot pressing with charge and discharge equipment for capacity division, and then degassing and tightening the battery until no free electrolyte exists in the battery core.
The multilayer coating diaphragm and the polymer battery prepared by the multilayer coating diaphragm have the advantages that:
1) The electrolyte retention capacity of the battery is remarkably improved, compared with a conventional polymer coated diaphragm, the wettability can be greatly improved, the infiltration rate of the electrolyte is equivalent to that of a ceramic diaphragm, the formed gel layer is uniform and stable, the interface stability can be improved, and the electrolyte has excellent cycle performance;
2) The diaphragm gel layer can be tightly attached to the surface of the electrode when the battery is in needling short circuit, and certain toughness is maintained, so that the contact internal resistance can be effectively improved, the temperature rise is reduced, and the safety of the battery is improved;
3) The preparation process is simple, and the production cost is reduced;
4) The prepared polymer battery has no free electrolyte inside, and the risk of leakage of the aluminum plastic film corroded by the liquid electrolyte is greatly reduced.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent by describing in more detail exemplary embodiments thereof with reference to the attached drawings.
Fig. 1 is a schematic cross-sectional and planar structure of a diaphragm.
Fig. 2 is a schematic composite view of a separator of a soft pack battery.
Fig. 3 is a graph showing the cycle at 45 c after the assembled pouch cells of comparative examples and examples 1 to 6 were assembled.
Fig. 4 is a view showing the disassembled interface after 10 cycles of standard charge and discharge of the assembled pouch cells of comparative examples and examples 1 to 6.
FIG. 5 is a graph showing the height of the liquid surface after the membrane of comparative example and examples 1 to 6 is clamped and fixed by a glass slide and immersed in the electrolyte at the same height for 40 seconds.
Reference numerals illustrate:
1-membrane substrate, 2-low swelling polymer coating, 3-high swelling polymer coating, 4-front clamp, 5-back clamp, 6-silica gel pad, 7-cell.
Detailed Description
Preferred embodiments of the present invention will be described in more detail below. While the preferred embodiments of the present invention are described below, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein.
The invention provides a multilayer coated separator comprising a separator substrate and a multilayer polymer coating coated on the separator substrate; the multi-layer polymeric coating comprises a low swell ratio polymeric coating and a high swell ratio polymeric coating; the polymer coating with low swelling rate is uniformly coated on the surface of the diaphragm substrate; the Gao Rongzhang rate polymer coating is applied over the low-swell rate polymer coating at intervals. A schematic of the cross-section and planar structure of the diaphragm is shown in fig. 1.
Alternatively, the Gao Rongzhang-rate polymeric coating component has a maximum swelling and imbibing capacity in the electrolyte of 20-100% of its mass, and the low-swelling polymeric coating component should have a maximum swelling and imbibing capacity in the electrolyte of less than 20%.
Optionally, the membrane substrate is at least one of PE, PP, cellulose, PET, PI, nonwoven fabric and electrospun membrane.
Optionally, the raw material for forming the polymer coating is polymer binder slurry or mixed slurry of polymer binder and inorganic material;
The inorganic material is at least one of aluminum oxide, magnesium hydroxide, layered composite oxide, boehmite, silicon dioxide and silicon carbide;
the polymer binder includes a high swelling ratio polymer binder and a low swelling ratio polymer binder;
The Gao Rongzhang-rate polymer binder is preferably at least one of polyvinylidene fluoride and polyacrylonitrile, and the low-swelling polymer binder is preferably at least one of polyethyl acrylate, polymethyl methacrylate and ethylene-tetrafluoroethylene copolymer;
The mass fraction of the inorganic material in the mixed slurry is 0-90%, and the mass fraction of the polymer binder is 10-100%.
Optionally, the multilayer polymeric coating is at least two layers;
The multilayer polymeric coating is applied to one or both sides of the separator substrate.
Optionally, the total thickness of the low-swell ratio polymer coating and the Gao Rongzhang-swell ratio polymer coating is no greater than 6 μm;
the thickness of the low-swelling polymer coating is 1-2 mu m;
The Gao Rongzhang-rate polymer coating thickness is 2-4 mu m;
The Gao Rongzhang-rate polymer coating is preferably applied in stripe diagonal intervals of 500 μm-2mm.
And uniformly coating the slurry of the low-swelling polymer coating on the surface of the membrane substrate by adopting a gravure coating mode, and coating the slurry of the high-swelling polymer coating on the surface of the membrane substrate to prepare the multi-layer coating membrane.
In the invention, the low-swelling polymer coating can improve the mechanical strength of the diaphragm and ensure the cohesiveness between the diaphragm and the electrode; the high-swelling-ratio polymer coating can improve the electrolyte retention in the battery, and the electrolyte retention is mutually supplemented through different effects of the coatings, so that the wettability of the adhesive coating diaphragm is greatly improved, the cohesiveness between an electrode and the diaphragm is enhanced, the interface consistency is ensured, and the electrochemical performance and the safety performance of the battery are improved.
The invention also provides a polymer battery, which comprises a positive electrode, a negative electrode and a diaphragm, wherein the diaphragm is the multilayer coating diaphragm.
The invention also provides a preparation method of the polymer battery, which comprises the following steps:
(1) Uniformly coating the slurry of the low-swelling polymer coating on the surface of the membrane substrate by adopting an intaglio coating mode, and then coating the slurry of the high-swelling polymer coating at intervals to prepare a multi-layer coating membrane;
(2) Orderly stacking or winding a certain number of positive and negative plates and the multilayer coating diaphragm, and packaging the positive and negative plates and the multilayer coating diaphragm into a polymer battery by using an aluminum plastic film;
(3) Placing the battery into a pressure formation cabinet for heating and pressure formation after filling the battery, swelling the coating of the multilayer coating diaphragm, and firmly combining with the pole piece under the action of pressure;
(4) And connecting the battery after hot pressing with charge and discharge equipment for capacity division, and then degassing and tightening the battery until no free electrolyte exists in the battery core.
Optionally, the slurry of Gao Rongzhang-rate polymer coating includes an inorganic material, a high-swelling-rate polymer binder, and an organic solvent;
The slurry of the low-swelling polymer coating comprises an inorganic material, a low-swelling polymer binder and an organic solvent;
the organic solvent is preferably NMP; the inorganic material is preferably at least one of aluminum oxide, magnesium hydroxide, layered composite oxide, boehmite, silica, and silicon carbide.
Optionally, the positive and negative plates are both in direct contact with the Gao Rongzhang-rate polymer coating;
Preparing the polymer battery at the temperature of 60-85 ℃ and the pressure of 0.1-0.8 MPa;
The polymer battery is at least one of a soft package battery, a cylindrical battery and a square aluminum shell battery, and the soft package battery is preferred. A composite schematic of the separator of the soft-pack battery is shown in fig. 2.
According to the invention, the diaphragm gel layer can be tightly attached to the surface of the electrode when the battery is in needling short circuit, and certain toughness is maintained, so that the contact internal resistance can be effectively improved, the temperature rise is reduced, and the safety of the battery is improved; the prepared polymer battery has no free electrolyte inside, and the risk of leakage of the aluminum plastic film corroded by the liquid electrolyte is greatly reduced.
The present invention will be described in more detail with reference to examples and comparative examples.
Comparative example
1) Preparing a diaphragm:
a. a membrane with a base film of PE and a2 μm boehmite coating on both sides was used.
2) And (3) assembling the soft package battery:
b. 30 NCM622 ternary positive plates, 31 artificial graphite negative plates and 32 diaphragms are orderly stacked together.
C. and packaging the battery cells by using an aluminum plastic film, and assembling the battery cells into the 50Ah soft package battery.
D. The battery was injected with 1M LiPF 6 dissolved in EC: emc=3:7 (w/w) and the amount of injection was 3.3g/Ah.
3) Thermal compounding of the diaphragm electrode:
e. the battery is externally connected with an air bag, placed into a pressure formation cabinet at 30 ℃, and the anode and the cathode are respectively connected with charging and discharging equipment. The pressure of the pressure formation cabinet is regulated to be 0.6MPa, and the battery is compacted. The pre-charge procedure was set to 0.05C to 3.55V, left to stand for 1h,0.1C to 4.35V, left to stand for 10min, and stopped.
F. And after the pre-charging procedure is stopped, the external air bag is taken down, the pressure formation cabinet is decompressed, the battery is taken out, and the external liquid extraction pipe is used for extracting the battery gas.
G. Connecting the anode and the cathode of the battery with a charging and discharging device, setting the program to discharge 0.3C to 2.75V and charge 0.3C to 4.35V, standing for 10min, repeating the process for 3 times, and stopping.
H. and taking the battery off the charging and discharging equipment, externally connecting a liquid extracting pipe, extracting free electrolyte of the battery, and recording the quality of the battery.
Example 1
1) Preparing a diaphragm:
a. Coating one side of a PE separator substrate with a low-swelling polymer coating slurry (magnesium hydroxide: polyethyl acrylate=7:3), and a high-swelling polymer coating slurry (PVDF), wherein the low-swelling polymer coating was uniformly coated, the high-swelling polymer coating was coated on the low-swelling polymer coating at diagonal intervals of 500 μm, the coating thicknesses of the low-swelling polymer coating and the high-swelling polymer coating were 1 μm and 2 μm, respectively, and the other side of the separator was treated in the same manner, to prepare a coated separator.
2) Assembling the soft package battery with the comparative example;
3) Thermal compounding of the diaphragm electrode:
b. The battery is externally connected with an air bag, placed into a pressure formation cabinet at the room temperature of 30 ℃, and the anode and the cathode are respectively connected with charge and discharge equipment. The pressure of the pressure formation cabinet is regulated to be 0.6MPa, and the battery is compacted. The pre-charge procedure was set to 0.05C to 3.55V, left to stand for 1h,0.1C to 4.35V, left to stand for 10min, and stopped.
C. And after the pre-charging procedure is stopped, the external air bag is taken down, the pressure formation cabinet is decompressed, the battery is taken out, and the external liquid extraction pipe is used for extracting the battery gas.
D. The anode and the cathode of the battery are connected with charge-discharge equipment, the procedure was set to 0.2C discharge to 2.75V,0.2C charge to 3.9V, and rest for 10min, stopping.
E. And taking the battery off the charging and discharging equipment, putting the battery into a hot pressing cabinet, adjusting the temperature of the hot pressing cabinet to 70 ℃, and the pressure to 0.06Mpa, and carrying out hot pressing for 60 minutes. And after the battery is cooled, taking down the battery, externally connecting a liquid extracting pipe, extracting free electrolyte of the battery, and recording the quality of the battery.
Example 2
1) Preparing a diaphragm:
a. Coating one side of a PE membrane substrate with a low-swelling polymer coating slurry (boehmite: polyethyl acrylate=8:2) and a high-swelling polymer coating slurry (PVDF), wherein the low-swelling polymer coating is uniformly coated, the high-swelling polymer coating is coated on the low-swelling polymer coating at intervals of a slant line shape, the coating interval is 700 mu m, the coating thicknesses of the low-swelling polymer coating and the high-swelling polymer coating are respectively 1 mu m and 2 mu m, and the other side of the membrane is treated in the same way, so as to prepare a coated membrane.
2) Assembling the soft package battery with the comparative example;
3) The separator electrode was thermally recombined as in example 1.
Example 3
1) Preparing a diaphragm:
a. Coating one side of a PE membrane substrate with a low-swelling polymer coating slurry (boehmite: polyethyl acrylate=6:4) and a high-swelling polymer coating slurry (PVDF), wherein the low-swelling polymer coating is uniformly coated, the high-swelling polymer coating is coated on the low-swelling polymer coating at intervals of a slant line shape, the coating interval is 1000 μm, the coating thicknesses of the low-swelling polymer coating and the high-swelling polymer coating are respectively 1 μm and 2 μm, and the other side of the membrane is treated in the same way to prepare a coated membrane.
2) Assembling the soft package battery with the comparative example;
3) The separator electrode was thermally recombined as in example 1.
Example 4
1) Preparing a diaphragm:
a. Coating one side of a PE separator substrate with a low-swelling polymer coating slurry (Al 2O3: polyethyl acrylate=9:1) and a high-swelling polymer coating slurry (Al 2O3: pvdf=1:9), wherein the low-swelling polymer coating was uniformly coated, the high-swelling polymer coating was coated on the low-swelling polymer coating at an oblique line-like interval of 1000 μm, the coating thicknesses of the low-swelling polymer coating and the high-swelling polymer coating were 1 μm and 3 μm, respectively, and the other side of the separator was treated in the same manner to prepare a coated separator.
2) Assembling the soft package battery with the comparative example;
3) The separator electrode was thermally recombined as in example 1.
Example 5
1) Preparing a diaphragm:
a. Coating one side of a PE membrane substrate with a low-swelling polymer coating slurry (boehmite: polyethyl acrylate=8:2) and a high-swelling polymer coating slurry (PVDF), wherein the low-swelling polymer coating is uniformly coated, the high-swelling polymer coating is coated on the low-swelling polymer coating at intervals of a slant line shape, the coating interval is 2000 mu m, the coating thicknesses of the low-swelling polymer coating and the high-swelling polymer coating are respectively 1 mu m and 2 mu m, and the other side of the membrane is treated in the same way to prepare a coated membrane.
2) Assembling the soft package battery with the comparative example;
3) The separator electrode was thermally recombined as in example 1.
Example 6
1) Preparing a diaphragm:
a. Coating one side of a PE membrane substrate with a low-swelling polymer coating slurry (magnesium aluminum layered composite hydroxide: polyethyl acrylate=7:3) and a high-swelling polymer coating slurry (PVDF), wherein the low-swelling polymer coating is uniformly coated, the high-swelling polymer coating is coated on the low-swelling polymer coating at intervals of a slant line, the coating interval is 1000 μm, the coating thicknesses of the low-swelling polymer coating and the high-swelling polymer coating are 2 μm and 2 μm respectively, and the other side of the membrane is treated in the same way, so as to prepare a coated membrane.
2) Assembling the soft package battery with the comparative example;
3) The separator electrode was thermally recombined as in example 1.
Fig. 3 is a graph showing the cycle at 45 c after the assembled pouch cells of comparative examples and examples 1 to 6 were assembled. As can be seen from the cycle performance in fig. 3, the examples all have higher capacity retention than the comparative examples, and it can be seen that the separator multilayer coating can significantly improve the battery performance.
Fig. 4 is a view showing the disassembled interface after 10 cycles of standard charge and discharge of the assembled pouch cells of comparative examples and examples 1 to 6. As can be seen from fig. 4, the cell interface uniformity of the examples is significantly improved compared to the comparative examples.
FIG. 5 is a graph showing the height of the liquid surface after the membrane of comparative example and examples 1 to 6 is clamped and fixed by a glass slide and immersed in the electrolyte at the same height for 40 seconds. As can be seen from FIG. 5, the liquid absorption capacity and wettability of the separators of examples 1 to 6 were improved more than those of the comparative examples.
Test example 1
The separator samples prepared in comparative examples and examples 1 to 6 were subjected to liquid retention and air permeability tests. The method for testing the liquid retention amount comprises the following steps: and measuring the mass m 0 of the dry battery core, respectively assembling soft package battery injection liquid by using the prepared diaphragms, compounding, drawing the battery tightly after standard charge and discharge for 3 circles, and measuring the mass m 1 of the battery core, wherein the battery liquid retention amount=m 1-m0. The air permeability test method comprises the following steps: the membrane sample was selected to measure the average time required to permeate 100mL of gas. The results are shown in Table 1.
TABLE 1
As can be seen from the data of examples 1-3 in Table 1, when the thickness of the coating layer of the diaphragm is unchanged, the coating interval of the polymer coating layer with high swelling rate is increased, the air permeability of the diaphragm is improved to a certain extent, and the liquid retention amount is also improved accordingly. However, when the coating interval was further increased to example 5, the air permeability was increased, but the liquid retention amount was decreased, and it was estimated that the porosity was too high and the electrolyte was lost. It can be seen from examples 3, 4 and 6 that the liquid retention amount can be effectively improved by properly increasing the thickness of the high-swelling polymer coating or the low-swelling polymer coating when the coating interval is unchanged. And the proportion of the inorganic material and the binder in the coating of the embodiment is a preferable example.
Test example 2
The polymer batteries prepared in comparative examples and examples 1 to 6 were subjected to a battery needling test. The testing method comprises the following steps: the cell was then monitored for voltage drop and temperature rise by piercing it at 0.1mm/s to a depth of 6mm perpendicular to the cell surface using a stainless steel needle 1mm in diameter at 25 c, and the cell was brought to full state prior to testing. The results are shown in Table 2.
TABLE 2
As can be seen from the data of examples 1-3 of table 2, as the Gao Rongzhang rate polymer coating application interval increases, the high swelling rate polymer coating application amount decreases, the voltage drop by cell needling increases, and the temperature rise increases, and it is speculated that the gel layer can effectively increase the contact resistance, reduce the temperature rise, and slow down the occurrence of thermal runaway of the cell. It can be seen from examples 3 and 6 that the increased thickness of the low-swell polymer coating also has a certain reduction in the needling pressure drop and temperature rise.
Test example 3
The swelling capacity test of the polymer coating was carried out by drying a certain amount of the polymer slurry in a petri dish to form a film of about 0.5mm in thickness, cutting the film into a shape of 2cm x 2cm and accurately weighing the mass m 0, then placing the cut film and 20mL of electrolyte in a sample tube, heating to 70 ℃ and holding for 24 hours, then taking out the swollen film, wiping the liquid electrolyte on the surface, and rapidly weighing the mass m 1 with the swelling degree τ=100% × (m 1-m0)/m0. The results are shown in table 2.
TABLE 3 Table 3
From the test results of the comparative examples and the examples, it can be seen that the polymer battery using the multilayer coating separator of the present invention has improved liquid retention, wettability, interfacial uniformity and safety.
Compared with the existing diaphragm, in the design of the multi-layer coating diaphragm, the low-swelling rate polymer coating can improve the mechanical strength of the diaphragm and ensure the cohesiveness between the diaphragm and the electrode; the high-swelling-ratio polymer coating can improve the electrolyte retention in the battery, and the electrolyte retention is mutually supplemented through different effects of the coatings, so that the wettability of the adhesive coating diaphragm is greatly improved, the cohesiveness between an electrode and the diaphragm is enhanced, the interface consistency is ensured, and the electrochemical performance and the safety performance of the battery are improved.
The foregoing description of embodiments of the invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described.
Claims (10)
1. A multilayer coated separator comprising a separator substrate and a multilayer polymer coating applied to the separator substrate;
the multi-layer polymeric coating comprises a low swell ratio polymeric coating and a high swell ratio polymeric coating;
the polymer coating with low swelling rate is uniformly coated on the surface of the diaphragm substrate;
The Gao Rongzhang-rate polymer coating is coated on the low-swelling-rate polymer coating at intervals;
The low swell ratio polymer coating and the Gao Rongzhang th rate polymer coating have a total thickness of no more than 6 μm;
the thickness of the low-swelling polymer coating is 1-2 mu m;
The Gao Rongzhang-rate polymer coating thickness is 2-4 mu m;
The Gao Rongzhang-rate polymer coating is coated at stripe oblique line intervals, and the coating interval is 500 mu m-2mm;
the maximum swelling and imbibing capacity of the Gao Rongzhang-rate polymer coating component in the electrolyte is 20-100% of the mass of the polymer coating component, and the maximum swelling and imbibing capacity of the low-swelling rate polymer coating component in the electrolyte is below 20% of the mass of the polymer coating component;
The raw material for forming the polymer coating is polymer binder slurry or mixed slurry of polymer binder and inorganic material;
the polymer binder includes a high swelling ratio polymer binder and a low swelling ratio polymer binder;
the mass fraction of inorganic materials in the mixed slurry is 0-90%, and the mass fraction of the polymer binder is 10-100%;
the slurry of the low-swelling polymer coating includes an inorganic material, a low-swelling polymer binder, and an organic solvent.
2. The multilayer coated separator of claim 1 wherein the separator substrate is at least one of PE, PP, cellulose, PET, PI, nonwoven and electrospun separator.
3. The multilayer coated separator of claim 1 wherein the inorganic material is at least one of aluminum oxide, magnesium hydroxide, layered composite oxide, boehmite, silica, silicon carbide;
The Gao Rongzhang-rate polymer binder is at least one of polyvinylidene fluoride and polyacrylonitrile, and the low-swelling-rate polymer binder is at least one of polyethyl acrylate, polymethyl methacrylate and ethylene-tetrafluoroethylene copolymer.
4. The multilayer coated separator of claim 1 wherein said multilayer polymeric coating is at least two layers;
The multilayer polymeric coating is applied to one or both sides of the separator substrate.
5. A polymer battery comprising positive and negative electrodes and a separator, the separator being the multilayer coated separator of any one of claims 1-4.
6. The method for preparing a polymer battery according to claim 5, comprising the steps of:
(1) Uniformly coating the slurry of the low-swelling polymer coating on the surface of the membrane substrate by adopting an intaglio coating mode, and then coating the slurry of the high-swelling polymer coating at intervals to prepare a multi-layer coating membrane;
(2) Orderly stacking or winding a certain number of positive and negative plates and the multilayer coating diaphragm, and packaging the positive and negative plates and the multilayer coating diaphragm into a polymer battery by using an aluminum plastic film;
(3) Placing the battery into a pressure formation cabinet for heating and pressure formation after filling the battery, swelling the coating of the multilayer coating diaphragm, and firmly combining with the pole piece under the action of pressure;
(4) And connecting the battery after hot pressing with charge and discharge equipment for capacity division, and then degassing and tightening the battery until no free electrolyte exists in the battery core.
7. The polymer battery made from the multilayer coated separator of claim 6 wherein said slurry of Gao Rongzhang-rate polymer coating comprises an inorganic material, a high-swell polymer binder, and an organic solvent;
the slurry of the low-swelling polymer coating includes an inorganic material, a low-swelling polymer binder, and an organic solvent.
8. The polymer battery made from the multilayer coated separator of claim 7 wherein said organic solvent is NMP; the inorganic material is at least one of aluminum oxide, magnesium hydroxide, layered composite oxide, boehmite, silicon dioxide and silicon carbide.
9. The polymer battery made from the multilayer coated separator of claim 6 wherein said positive and negative electrode sheets are both in direct contact with said Gao Rongzhang rate polymer coating;
the temperature range for preparing the polymer battery is 60-85 ℃, and the pressure range is 0.1-0.8 MPa;
The polymer battery is at least one of a soft package battery, a cylindrical battery and a square aluminum shell battery.
10. The polymer battery made from the multilayer coated separator of claim 9 wherein the polymer battery is a pouch battery.
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| CN115064777B (en) * | 2022-07-08 | 2024-07-05 | 福州大学 | Gel electrolyte for lithium metal and preparation method and application thereof |
| CN115810873B (en) * | 2022-10-24 | 2024-09-06 | 宁德时代新能源科技股份有限公司 | Battery pack, battery cell, secondary battery, and power consumption device |
| CN115995657B (en) * | 2023-03-03 | 2024-04-23 | 江苏正力新能电池技术有限公司 | Composite diaphragm structure, electrode assembly and lithium battery |
| WO2024192602A1 (en) * | 2023-03-17 | 2024-09-26 | 宁德时代新能源科技股份有限公司 | Separator and preparation method therefor, secondary battery, and electric device |
| WO2024016952A1 (en) * | 2023-05-09 | 2024-01-25 | 湖北亿纬动力有限公司 | Composite separator and preparation method therefor, and secondary battery |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108711605A (en) * | 2018-07-10 | 2018-10-26 | 深圳中兴新材技术股份有限公司 | A kind of composite battery separator film, preparation method and battery |
| CN109103397A (en) * | 2018-09-28 | 2018-12-28 | 河南福森新能源科技有限公司 | A kind of preparation method of lithium ion battery ceramic coating membrane |
| CN111769253A (en) * | 2020-06-29 | 2020-10-13 | 天津力神电池股份有限公司 | Battery positive plate, flexible-package lithium fluorocarbon primary battery and preparation method thereof |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100528904B1 (en) * | 1999-04-21 | 2005-11-16 | 삼성에스디아이 주식회사 | lithum secondary battery and manufacturing method thereof |
| CN108767193B (en) * | 2018-06-06 | 2021-01-29 | 江苏卓高新材料科技有限公司 | Positive electrode containing low-swelling graphite coating and lithium battery |
| CN109148798B (en) * | 2018-08-08 | 2021-06-22 | 欣旺达电子股份有限公司 | Lithium ion battery, coating diaphragm and preparation method thereof |
| CN111180641A (en) * | 2018-11-09 | 2020-05-19 | 湖北江升新材料有限公司 | Diaphragm with self-crosslinking function and preparation method thereof |
| CN110137416A (en) * | 2019-05-15 | 2019-08-16 | 武汉理工大学 | A kind of polyolefin lithium electric separator preparation method |
| CN110783512B (en) * | 2019-10-17 | 2022-01-28 | 江苏海基新能源股份有限公司 | Soluble type lithium bis (fluorosulfonyl) imide/lithium magnesium silicate coating diaphragm for lithium ion battery and preparation method thereof |
| CN111312971B (en) * | 2020-03-02 | 2022-06-28 | 荣盛盟固利新能源科技有限公司 | Diaphragm, secondary battery and preparation method thereof |
| CN113363672A (en) * | 2020-03-06 | 2021-09-07 | 中材锂膜有限公司 | Spraying diaphragm for lithium ion battery and preparation method thereof |
-
2021
- 2021-11-24 CN CN202111407755.XA patent/CN114284642B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108711605A (en) * | 2018-07-10 | 2018-10-26 | 深圳中兴新材技术股份有限公司 | A kind of composite battery separator film, preparation method and battery |
| CN109103397A (en) * | 2018-09-28 | 2018-12-28 | 河南福森新能源科技有限公司 | A kind of preparation method of lithium ion battery ceramic coating membrane |
| CN111769253A (en) * | 2020-06-29 | 2020-10-13 | 天津力神电池股份有限公司 | Battery positive plate, flexible-package lithium fluorocarbon primary battery and preparation method thereof |
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