CN115275519B - Inorganic coating battery diaphragm, preparation method thereof and battery - Google Patents

Inorganic coating battery diaphragm, preparation method thereof and battery Download PDF

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Publication number
CN115275519B
CN115275519B CN202211036875.8A CN202211036875A CN115275519B CN 115275519 B CN115275519 B CN 115275519B CN 202211036875 A CN202211036875 A CN 202211036875A CN 115275519 B CN115275519 B CN 115275519B
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inorganic
coating
inorganic particles
substrate
battery separator
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CN115275519A (en
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王连广
刘杲珺
高飞飞
白麟
沙宗枫
孙婧
汤晓
秦文娟
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Sinoma Lithium Film Co Ltd
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Sinoma Lithium Film Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/457—Separators, membranes or diaphragms characterised by the material having a layered structure comprising three or more layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Cell Separators (AREA)

Abstract

The invention provides an inorganic coating battery diaphragm, a preparation method thereof and a battery, and relates to the technical field of battery diaphragms, wherein the inorganic coating battery diaphragm comprises: a substrate and an inorganic particle coating layer covering one or both sides of the substrate; the inorganic particle coating includes first inorganic particles and second inorganic particles; the particle diameter D1 (50) of the first inorganic particles is 5-100nm, and the particle diameter D2 (50) of the second inorganic particles is 600-1000nm; the mass ratio w1 of the first inorganic particles to the mixed inorganic particles is 5-20%; the particle size distribution concentration of the mixed inorganic particles is more than 0 and less than 1.3; the porosity of the inorganic particle coating is 52-59%, and the air permeability increment value per micron is 1-20 s/(100 mL, mum); has high electrical strength, and the electrical strength increase value is 150V/μm-500V/μm.

Description

Inorganic coating battery diaphragm, preparation method thereof and battery
Technical Field
The invention relates to the technical field of battery diaphragms, in particular to an inorganic coating battery diaphragm, a preparation method thereof and a battery.
Background
Currently, less researches are conducted on the breakdown resistance of the separator, and the breakdown resistance of the separator greatly influences the safety of the battery. As in the prior art CN114243093a, a preparation method of an aramid separator with high breakdown strength is studied, but based on market conditions, the market of the aqueous inorganic coating separator is large, and there is a great demand for improvement of breakdown resistance, so that an aqueous inorganic coating separator with high breakdown resistance is needed.
In view of this, the present invention has been made.
Disclosure of Invention
One of the purposes of the invention is to provide an inorganic coating battery diaphragm which has high electrical strength and improves the safety performance of a battery.
The second object of the invention is to provide a preparation method of the inorganic coating battery separator.
It is a further object of the present invention to provide a battery comprising the inorganic coated battery separator.
In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:
the first aspect of the present invention provides an inorganic coated battery separator comprising: a substrate and an inorganic particle coating layer covering one or both sides of the substrate;
the inorganic particle coating includes mixed inorganic particles including first inorganic particles and second inorganic particles; the particle diameter D1 (50) of the first inorganic particles is 5-100nmm, and the particle diameter D2 (50) of the second inorganic particles is 600-1000nm;
the mass ratio w1 of the first inorganic particles to the mixed inorganic particles is 5-20%;
the particle size distribution concentration of the mixed inorganic particles is 0< S3<1.3, S3=w1×S1+ (1-w 1) ×S2, S1= [ D1 (90) -D1 (10) ]/D1 (50), S2= [ D2 (90) -D2 (10) ]/D2 (50), and S1 > S2;
the porosity of the inorganic particle coating is 52-59%;
the inorganic coating battery separator has an air permeability increase value of 1-20 s/(100 mL, mum) per micron and/or an electrical strength of 150V/mum-500V/mum compared with the electrical strength increase value of the substrate.
The respective parts will be described in detail.
Substrate material
The substrate is a small-aperture substrate. The base material is a high molecular polymer and comprises any one of polyethylene porous membrane, polypropylene porous membrane, polyethylene/polypropylene mixed porous membrane, polyethylene/polypropylene/polyethylene three-layer porous membrane, polyvinylidene fluoride porous membrane, polyimide porous membrane, non-woven fabric and the like.
The thickness of the substrate is not particularly limited and may be, for example, 4 to 16. Mu.m.
The average pore diameter of the substrate is not particularly limited and may be, for example, 10 to 40nm.
The porosity of the substrate is not particularly limited and may be, for example, 30 to 40%.
The air permeability of the substrate is not particularly limited, and may be, for example, 70 to 200s/100mL.
Inorganic particle coating
The inorganic particle coating comprises mixed inorganic particles;
the mixed inorganic particles include first inorganic particles and second inorganic particles;
the first inorganic particles and the second inorganic particles are respectively and independently selected from one or two of alpha-alumina, gamma-alumina, boehmite, calcium carbonate, hydrotalcite, montmorillonite, spinel, titanium dioxide, silicon dioxide, zirconium dioxide, magnesium oxide, calcium oxide, beryllium oxide, magnesium hydroxide, calcium hydroxide and silicon carbide;
the particle diameter D1 (50) of the first inorganic particles is 5-100nm (e.g., 10, 20, 30, 40, 50, 60, 70, 80, 90 nm), and the particle diameter D2 (50) of the second inorganic particles is 600-1000nm (e.g., 700, 800, 900, 1000 nm);
the mass ratio w1 of the first inorganic particles to the mixed inorganic particles is 5-20% (e.g. 6, 7, 8, 10, 12, 15, 16, 18%);
the particle size distribution concentration of the mixed inorganic particles satisfies: 0< S3<1.3, s3=w1×s1+ (1-w 1) ×s2, where s1= [ D1 (90) -D1 (10) ]/D1 (50), s2= [ D2 (90) -D2 (10) ]/D2 (50), and S1 > S2.
D1 (50), D1 (10), D1 (90) represent D50 particle diameter, D10 particle diameter, D90 particle diameter of the first inorganic particles; d2 (50), D2 (10), D2 (90) represent the D50 particle diameter, D10 particle diameter, D90 particle diameter of the second inorganic particles.
The inorganic particle coating adopts two kinds of inorganic particles with different particle diameters to match and use, respectively meets the conditions, controls the proportion of the two inorganic particles to be in a certain range, and simultaneously ensures that the particle distribution concentration of the first inorganic particles, the second inorganic particles and the mixed particles are in the range, so that the first inorganic particles are completely distributed in gaps of the second inorganic particles, the gaps of the coating are reduced, and uniform micro gaps are formed, thereby improving the voltage resistance performance of the coated diaphragm.
The inorganic particle coating may also include a hydrophobic binder.
The hydrophobic binder includes, but is not limited to, at least one of methacrylic acid, polyacrylate, polymethyl methacrylate, polyacrylonitrile, polyamide.
The thickness of the inorganic particle coating layer is not particularly limited, and may be, for example, 1 to 3 μm (single layer).
In addition, the porosity of the inorganic particle coating is controlled to be 52-59% (for example 52, 53, 54, 55, 56, 58 and 59%), and the smaller the porosity of the coating is, the less air in the coating is indicated, so that the electric strength is improved; the air permeability increase per micron is 1-20 s/(100 mL, mum) (e.g., 2, 5, 6, 8, 10, 12, 15, 16, 18, 20 s/(100 mL, mum)), and the smaller the coating porosity, the more air permeability of the coating increases, which results in an increase in the internal resistance of the battery, thus the relationship between the electrical strength and the air permeability increase of the coating needs to be balanced.
The porosity of the substrate can be tested according to the method specified in GB/T36363-2018.
Coating porosity = (coating grammage-substrate grammage)/(coating thickness x inorganic particle density x 10) -6 )；
Coating grammage-coating film weight per square meter (g/m) 2 )；
Substrate gram weight-substrate weight per square meter (g/m) 2 )；
Coating thickness-thickness of coating (μm);
inorganic particle Density-true Density of inorganic particles used (kg/m) 3 )。
Coating air permeability increase value= (air permeability of inorganic coating battery separator-air permeability of substrate)/coating thickness.
The air permeability can be tested according to the method specified in GB/T36363-2018, and the air permeability test instrument is of the type G-500 of the Asahi semen.
The electrical strength of the inorganic coating battery separator of the present invention is increased by 150V/μm to 500V/μm compared to the electrical strength of the substrate.
The electrical strength of the inorganic coated battery separator was increased by = (electrical strength of inorganic coated battery separator-electrical strength of substrate)/coating thickness as compared to the electrical strength of the substrate.
The electrical strength test method can be used for testing according to the method specified in GB/T36363-2018, and the electrical strength tester is model YD9810A of Yangzi of Changzhou.
According to the invention, the mixed inorganic particles are prepared into slurry, and the slurry is coated on the PE/PP substrate with small aperture, so that the coating is more compact, the electrical strength of the diaphragm is improved, and the safety performance of the battery is further improved.
The invention provides a preparation method of the inorganic coating battery diaphragm, which comprises the following steps:
(1) Mixing the first inorganic particles with the second inorganic particles in proportion to prepare mixed inorganic particles;
(2) Adding the mixed inorganic particles obtained in the step (1) into water for dispersion to obtain mixed inorganic particle dispersion liquid;
(3) Adding a hydrophobic binder into the mixed inorganic particle dispersion liquid in the step (2), uniformly stirring, and filtering to obtain inorganic slurry;
(4) Uniformly coating the inorganic slurry in the step (3) on one or both sides of the small-aperture substrate to obtain a coating film coated with inorganic particles;
(5) And drying the water in the coating by using an oven to obtain the inorganic coating battery diaphragm.
The steps are described in detail below.
And (3) uniformly mixing the components in the step (1) by using a dry mixer.
The dispersing method in the step (2) includes, but is not limited to, one of high-speed dispersing machine dispersing, grinding dispersing and ultrasonic dispersing.
The viscosity (25 ℃) of the inorganic slurry of step (3) may be 10 to 60 mpa.s.
The addition amount of the hydrophobic binder (solid) in the step (3) accounts for 3-7% of the coating.
The coating mode of the step (4) includes, but is not limited to, any one of micro gravure roll coating and wire rod coating.
The baking oven in the step (5) is used for baking by hot air; preferably, the drying temperature is controlled between 40 and 80 ℃.
According to a third aspect of the present invention, there is provided a battery comprising the above inorganic coating battery separator.
The inorganic coated battery separator can be used for various kinds of batteries, and can be used in secondary batteries, such as lithium ion batteries, sodium ion batteries, and the like.
The beneficial effects are that:
two different inorganic particles meeting the requirements are mixed according to a fixed proportion to prepare slurry, and the slurry is coated on a substrate, so that the coating is more compact and uniform, the electric strength of a coated diaphragm can be greatly improved, and the safety performance of a battery is further improved.
Drawings
Fig. 1 is an SEM image of the inorganic coated battery separator prepared in example 1.
Detailed Description
The technical solutions of the present invention will be clearly and completely described in connection with the embodiments, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention is further illustrated by the following examples, which are provided for illustrative purposes only and are not to be construed as limiting the scope of the invention as claimed.
Unless otherwise indicated, all materials, reagents, methods and the like used in the examples are those conventionally used in the art.
S1＝[D1(90)-D1(10)]/D1(50)；
S2＝[D2(90)-D2(10)]/D2(50)；
S3＝w1×S1+(1-w1)×S2。
Example 1
0.3kg of first inorganic particles (alumina particles) having a D50 of 60nm and an S1 of 1.14 and 5.7kg of second inorganic particles (alumina particles) having a D50 of 500nm and an S2 of 1.02 were uniformly mixed by using a dry mill, the above-mentioned 6kg of uniformly mixed inorganic particles were added to 10kg of water, dispersed at a high speed for 40 minutes, and then ground by using a grinder for 50 minutes to obtain an inorganic particle dispersion, 0.8kg (trade name 104, solid content 40%) of a modified polyacrylate emulsion was weighed, added to the dispersion, stirred for 30 minutes, and then filtered by using a 400-mesh filter to obtain an inorganic slurry.
Selecting a wet synchronous biaxially oriented polyethylene substrate with the thickness of 7 mu m, the porosity of 34%, the aperture of 20nm and the air permeability of 145s/100mL, and uniformly coating the prepared inorganic slurry on two sides of the substrate in a gravure coating mode, wherein the coating thickness is 1 mu m.
The coated inorganic slurry membrane enters an oven to set the temperature to 60 ℃, and finally the inorganic coating membrane is obtained through rolling, and SEM is shown in figure 1. The thickness of the resulting inorganic coated separator was 9 μm, and the electrical strength was 1410V.
Example 2
The present example differs from example 1 in that the weight of the first inorganic particles is 0.6kg and the weight of the second inorganic particles is 5.4kg. The thickness of the resulting inorganic coated separator was 9 μm, and the electrical strength was measured to be 1590V.
Example 3
The present embodiment differs from embodiment 1 in that the weight of the first inorganic particles is 1kg and the weight of the second inorganic particles is 5kg. The thickness of the resulting inorganic coated separator was 9 μm, and the electrical strength was measured to be 1940V.
Example 4
The present example differs from example 1 in that the weight of the first inorganic particles is 1.2kg and the weight of the second inorganic particles is 4.8kg. The thickness of the resulting inorganic coated separator was 9 μm, and the electrical strength was found to be 1450V.
Example 5
The present embodiment differs from embodiment 3 in that the particle size distribution concentration ratio s1=1.03 of the first inorganic particles and the particle size distribution concentration ratio s2=0.97 of the second inorganic particles. The thickness of the resulting inorganic coated separator was 9 μm, and the electrical strength was measured to be 1980V.
Example 6
This example differs from example 3 in that the pore diameter of the substrate used was 25nm, the thickness of the resulting inorganic coated separator was 9 μm, and the electrical strength was measured to be 1910V.
Comparative example 1
The electrical strength of the wet synchronous biaxially oriented polyethylene substrate was measured to be 1100V by selecting a wet synchronous biaxially oriented polyethylene substrate having a thickness of 7 μm and a porosity of 34% and a pore diameter of 20 nm.
Comparative example 2
The electrical strength was determined to be 1070V by selecting a wet-process synchronous biaxially oriented polyethylene substrate having a thickness of 7 μm and a porosity of 34% and a pore diameter of 25 nm.
Comparative example 1
Adding 6kg of second inorganic particles with D50 of 60nm and S2 of 1.02 into 10kg of water, dispersing at high speed for 40min, grinding for 50min by using a grinder to obtain inorganic particle dispersion liquid, weighing 0.8kg of modified polyacrylate emulsion, adding into the dispersion liquid, stirring for 30min, and filtering by using a 400-mesh filter screen to obtain inorganic slurry.
The wet synchronous biaxially oriented polyethylene substrate with the thickness of 7 mu m, the porosity of 34%, the pore diameter of 20nm and the air permeability of 145s/100mL is selected, and the prepared inorganic slurry is uniformly coated on the two sides of the substrate in a gravure coating mode, wherein the coating thickness is 1 mu m.
And (3) the coated inorganic slurry diaphragm enters an oven to set the temperature to 60 ℃, and finally, the inorganic coating diaphragm is obtained through rolling. The thickness of the resulting inorganic coating film was 9. Mu.m, and the electrical strength was measured to be 1200V.
Comparative example 2
The comparative example was different from example 1 in that the weight of the first inorganic particles used was 3.6kg, the weight of the second inorganic particles was 2.4kg, the thickness of the resulting inorganic coated separator was 9 μm, and the electrical strength was measured to be 1260V.
Comparative example 3
The present comparative example was different from comparative example 1 in that 6kg of the first inorganic particles having a D50 of 60nm and an S1 of 1.14 were used, the thickness of the obtained inorganic coating film was 9. Mu.m, and the electrical strength was measured to be 1300V.
Comparative example 4
The present comparative example differs from example 3 in that the first inorganic particles used had a particle size distribution concentration s1=2.88, and the resulting inorganic coated separator had a thickness of 9 μm and an electrical strength of 1340V was measured.
Comparative example 5
The present comparative example differs from example 3 in that the second inorganic particles used had a particle size distribution concentration s2=1.84, and the resulting inorganic coated separator had a thickness of 9 μm and an electrical strength of 1350V was measured.
Comparative example 6
The comparative example differs from example 3 in that the oven temperature was set at 85℃and the coating porosity at 59.3% and the thickness of the resulting inorganic coated separator was 9. Mu.m, and the electrical strength was found to be 1360V.
Test case
And (3) carrying out an electrical strength test on the prepared diaphragm, wherein the test method comprises the following steps of: the membrane was cut into 100mm x 100mm squares and tested using the national standard GB/T36363-2018 test method. The results are shown in Table 1.
TABLE 1
The results in table 1 show that:
1. when the first inorganic particles account for less than or equal to 16.7 percent of the total particle weight, the electrical strength of the coating diaphragm is increased along with the increase of the first inorganic particles, the breakdown voltage of the converted coating is gradually increased, and when the ratio of the first inorganic particles is 5 percent, the electrical strength of the coating reaches 155V/mu m; as the first inorganic particles continued to increase, the electrical strength of the coating decreased, and at a 20% ratio, the electrical strength of the coating was 175V/μm. This is because as the amount of the first inorganic particles increases, bridging occurs between the first inorganic particles, and more large holes occur, resulting in a decrease in the electrical strength of the coating.
2. Different particle size distribution concentrations of the inorganic particles show different results, and as the particle size distribution concentration increases, the electrical strength of the coating tends to decrease, because the particle size distribution is wider, part of the first inorganic particles cannot be embedded in the gaps of the second inorganic particles, so that the coating has more gaps, and the electrical strength of the coating is low.
3. The two base materials with different pore diameters are adopted, the smaller the pore diameter of the base material is, the higher the electric strength of the base material is, and the same coating has no influence on the electric strength of the coating.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims (18)

1. An inorganic coated battery separator, comprising:
a substrate and an inorganic particle coating layer covering one or both sides of the substrate;
the inorganic particle coating includes mixed inorganic particles including first inorganic particles and second inorganic particles; the particle diameter D1 (50) of the first inorganic particles is 5-100nm, and the particle diameter D2 (50) of the second inorganic particles is 600-1000nm;
the mass ratio w1 of the first inorganic particles to the mixed inorganic particles is 5-20%;
particle size distribution concentration 0< S3<1.3, s3=w1×s1+ (1-w 1) ×s2, s1= [ D1 (90) -D1 (10) ]/D1 (50), s2= [ D2 (90) -D2 (10) ]/D2 (50), and S1 > S2;
and the porosity of the inorganic particle coating is 52-59%.
2. The inorganic coated battery separator of claim 1, wherein the inorganic particle coating has an increase in air permeability per micron of from 1 to 20 s/(100 mL, μm); and/or
The electrical strength of the inorganic coating battery separator is increased by 150V/μm to 500V/μm compared with the electrical strength of the substrate.
3. The inorganic coated battery separator according to claim 1, wherein the substrate is selected from any one of a polyethylene porous film, a polypropylene porous film, a polyethylene/polypropylene hybrid porous film, a polyethylene/polypropylene/polyethylene three-layer porous film, a polyvinylidene fluoride porous film, a polyimide porous film, and a nonwoven fabric.
4. The inorganic coated battery separator of claim 1, wherein the substrate has a thickness of 4-16 μm.
5. The inorganic coated battery separator of claim 1, wherein the average pore size of the substrate is 10-40nm.
6. The inorganic coated battery separator of claim 1, wherein the porosity of the substrate is 30-40%.
7. The inorganic coated battery separator of claim 1, wherein the substrate has a permeability of 70-200s/100mL.
8. The inorganic coated battery separator of claim 1, wherein the first and second inorganic particles are each independently selected from at least one of α -alumina, γ -alumina, boehmite, calcium carbonate, hydrotalcite, montmorillonite, spinel, titania, silica, zirconia, magnesia, calcia, beryllia, magnesium hydroxide, calcium hydroxide, silicon carbide.
9. The inorganic coated battery separator of claim 1, wherein the inorganic particle coating layer further comprises a hydrophobic binder;
the hydrophobic binder is at least one selected from methacrylic acid, polyacrylate, polymethyl methacrylate, polyacrylonitrile and polyamide.
10. The inorganic coated battery separator of claim 1, wherein the inorganic particle coating has a thickness of 1-3 μm.
11. A method for preparing the inorganic coating battery separator according to any one of claims 1 to 10, comprising the steps of:
(1) Mixing the first inorganic particles with the second inorganic particles in proportion to prepare mixed inorganic particles;
(2) Adding the mixed inorganic particles obtained in the step (1) into water for dispersion to obtain mixed inorganic particle dispersion liquid;
(3) Adding an optional hydrophobic binder into the mixed inorganic particle dispersion liquid in the step (2), uniformly stirring, and filtering to obtain inorganic slurry;
(4) Uniformly coating the inorganic slurry in the step (3) on one or both sides of a substrate to obtain a coating film coated with inorganic particles;
(5) And drying the water in the coating by using an oven to obtain the inorganic coating battery diaphragm.
12. The method according to claim 11, wherein the dispersing method in the step (2) comprises one of high-speed dispersing machine dispersing, grinding dispersing, and ultrasonic dispersing.
13. The method according to claim 11, wherein the viscosity of the inorganic slurry in the step (3) is 10 to 60 mPa-s.
14. The method of claim 11, wherein the hydrophobic binder of step (3) is added in an amount of 3-7% of the total mass of the mixed inorganic particles and hydrophobic binder.
15. The method of claim 11, wherein the coating in step (4) comprises one of micro gravure roll coating and bar coating.
16. The method of claim 11, wherein the oven drying in step (5) is performed with hot air.
17. The method according to claim 11, wherein the drying temperature is controlled to 40-80 ℃.
18. A battery comprising the inorganic coated battery separator of any one of claims 1-10.
CN202211036875.8A 2022-08-29 2022-08-29 Inorganic coating battery diaphragm, preparation method thereof and battery Active CN115275519B (en)

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