CN112909434A - Lithium ion battery diaphragm and preparation method thereof and lithium ion battery - Google Patents
Lithium ion battery diaphragm and preparation method thereof and lithium ion battery Download PDFInfo
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- CN112909434A CN112909434A CN201911129230.7A CN201911129230A CN112909434A CN 112909434 A CN112909434 A CN 112909434A CN 201911129230 A CN201911129230 A CN 201911129230A CN 112909434 A CN112909434 A CN 112909434A
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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
- 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
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
The invention provides a lithium ion battery diaphragm, a preparation method thereof and a lithium ion battery. The lithium ion battery separator comprises a base film and a coating coated on the surface of the base film; the coating comprises the following raw materials: 80-93% of dimethylacetamide, 2-10% of polyvinylidene fluoride and hexafluoropropylene copolymer, 2-15% of alpha crystal ceramic and 2-15% of gamma crystal ceramic. The preparation method of the lithium ion battery diaphragm comprises the following steps: coating dimethylacetamide on the surface of a base film, mixing the raw materials to obtain slurry, and coating the slurry after the base film is transparent to obtain the coating; and sequentially sending the base film coated with the coating into a coagulating bath system and a water washing system for treatment to obtain the lithium ion battery diaphragm. The lithium ion battery comprises the lithium ion battery diaphragm. The lithium ion battery diaphragm provided by the application has the advantages of strong cohesiveness, good permeability, high liquid absorption and retention capacity, and good safety of the prepared lithium ion battery.
Description
Technical Field
The invention relates to the field of lithium ion batteries, in particular to a lithium ion battery diaphragm, a preparation method thereof and a lithium ion battery.
Background
In recent years, the consumption of lithium ion batteries, particularly soft package batteries, is greatly increased, and the market space is huge. Different from square, cylindrical and aluminum-shell batteries, the soft package battery adopts an aluminum-plastic packaging film as the outer shell of the battery, the thickness of the aluminum-plastic film is about 110 mu m or less, and the appearance is soft and easy to deform. When the battery is invalid, the battery expands, the aluminum plastic film bulges, and the shell breakage caused by the increase of the pressure in the battery can not be caused. In addition, the weight of the soft package battery is 40% lighter than that of a steel shell battery with the same capacity, the capacity of the soft package battery is 10-15% higher than that of the steel shell battery with the same specification, the internal resistance is small, and the design is flexible.
The polyolefin separator in the prior art has the main problems that: 1. in the coating process, coating substances can enter the inner part of micropores of the base membrane, so that the micropores of the base membrane are blocked, the permeability of the pores is poor, and the rate discharge characteristic of the battery is influenced; 2. in the production process of the battery, the diaphragm is subjected to hot pressing procedures of heating and pressurizing for 2 times, wherein the coating is soaked and swelled by electrolyte to form a soft phase after hot pressing, particularly after liquid injection, before liquid injection of the battery core is performed, and the coating is very easy to thin and block the aperture during hot pressing; 3. the problem that the liquid absorption and retention capacity of the diaphragm to the electrolyte is poor is generally existed.
In view of this, the present application is specifically made.
Disclosure of Invention
The invention aims to provide a lithium ion battery diaphragm, a preparation method thereof and a lithium ion battery, so as to solve the problems.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a lithium ion battery separator comprises a base film and a coating layer coated on the surface of the base film;
the coating comprises the following raw materials in percentage by mass: 80-93% of dimethylacetamide, 2-10% of polyvinylidene fluoride and hexafluoropropylene copolymer, 2-15% of alpha crystal ceramic and 2-15% of gamma crystal ceramic.
Through adding Dimethylacetamide (DMAC) and polyvinylidene fluoride and hexafluoropropylene copolymer (PVDF-HFP) in the coating for the coating becomes oily coating, can improve the adhesion degree between diaphragm and the polar plate, increases the deflection of electric core, thereby improves laminate polymer battery's security. In addition, the distance between the oily PVDF membrane and the polar plate is small, so that the thickness of the battery core can be effectively reduced, and the capacity of the battery is increased under the condition of the same specification and size; and the electrolyte absorption and retention capacity is large, which is beneficial to improving the cycle performance of the battery. The alpha crystal form ceramic is used as a framework of the coating and mainly used for providing a supporting force for compression resistance; the larger specific surface area of the gamma crystal form ceramic can be used for regulating and controlling the viscosity of the material. By adopting the two ceramics, the use of other pore-forming agents and the occurrence of side reactions of the battery caused by unclean cleaning of the other pore-forming agents can be effectively avoided; in addition, the waste liquid treatment component is less, and the treatment difficulty is small.
Alternatively, the raw material of the coating layer, in mass percentage, dimethylacetamide may be any value between 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, and 80-93%; the polyvinylidene fluoride and hexafluoropropylene copolymer can be any value between 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% and 2-10%; the alpha crystalline form ceramic may be any value between 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, and 2-15%; the gamma-crystalline ceramic may be any value between 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, and 2-15%.
Preferably, the coating layer is disposed on both surfaces of the base film composed of a length direction and a width direction;
preferably, the coating has a single-sided thickness of 3-5 μm.
The thickness of the coating layer is preferably selected so that, after hot pressing twice inside the battery, a balance among the thickness, specific energy, and liquid absorption amount can be obtained to optimize the performance of the separator in various aspects. The smaller the thickness, the higher the specific energy, and the larger the thickness, the more electrolyte is absorbed relatively, and the longer the cycle life of the battery.
Alternatively, the one-sided thickness of the coating may be any value between 3 μm, 4 μm, 5 μm, and 3-5 μm.
Preferably, the alpha crystal form ceramic is submicron particles, and the gamma crystal form ceramic is nano-scale particles;
preferably, the alpha crystal ceramic is alpha-Al2O3The gamma crystal ceramic is gamma-Al2O3。
Alpha crystal form ceramics and gamma crystal form ceramics are selected as pore formers, the particle sizes of the alpha crystal form ceramics and the gamma crystal form ceramics are selected, large and small particles are adopted to be mixed and overlapped to construct a structure similar to reinforced concrete, the failure of the battery caused by the compression of a membrane is effectively avoided, the pores obtained by the method are large-aperture and deep-porous structures instead of a layered network structure in the prior art, the pores cannot be mutually blocked like network pores in the hot pressing process, the pores can still be transparent in the hot pressing process, and the battery can keep excellent rate discharge characteristics.
Optionally, the base film is a polyolefin film having micropores;
preferably, the thickness of the base film is 7 to 9 μm.
The thickness of the base film is controlled, so that the whole thickness of the diaphragm obtained by the method is 13-19 mu m, and the final thickness of the diaphragm after twice hot pressing can be controlled to be 10-15 mu m, so that the diaphragm can obtain high specific energy, good cycle performance and service life, and good safety performance.
Alternatively, the thickness of the base film may be any value between 7 μm, 8 μm, 9 μm, and 7-9 μm.
The preparation method of the lithium ion battery separator comprises the following steps:
coating dimethylacetamide on the surface of a base film, mixing the raw materials to obtain slurry, and coating the slurry after the base film is transparent to obtain the coating;
and sequentially sending the base film coated with the coating into a coagulating bath system and a water washing system for treatment to obtain the lithium ion battery diaphragm.
The pores of the base film are pre-filled with dimethylacetamide, and then the coating slurry is coated, so that the coating slurry can be effectively prevented from entering the micropores of the base film.
The diaphragm processed by the preparation method provided by the application has good permeability of the holes of the whole diaphragm, and provides a good ion transmission channel for the rate discharge characteristic of a battery
Preferably, the temperature of the slurry is 25-35 ℃;
preferably, the coating tension of the base film is less than or equal to 30N/m when the slurry is coated.
The slurry temperature and coating tension are preferably selected to have the effect of controlling the coating.
Alternatively, the temperature of the slurry may be 25 ℃, 26 ℃, 27 ℃, 28 ℃, 29 ℃, 30 ℃, 31 ℃, 32 ℃, 33 ℃, 34 ℃, 35 ℃ and 25-35 ℃.
Preferably, the coagulation bath system comprises a first-stage coagulation bath, a second-stage coagulation bath and a third-stage coagulation bath which are arranged in sequence;
preferably, the mass concentration of the dimethylacetamide aqueous solution in the primary coagulation bath is 70-90%, the mass concentration of the dimethylacetamide aqueous solution in the secondary coagulation bath is 40-70%, and the mass concentration of the dimethylacetamide aqueous solution in the tertiary coagulation bath is 10-40%;
preferably, the mass concentration of the dimethylacetamide aqueous solution in the water washing system is less than or equal to 3%.
And a high-concentration plasticizing bath system is adopted, so that the liquid-liquid phase separation time is delayed, the phase separation speed is controlled, the pore diameter is adjusted, and the phenomenon that the coating deforms and blocks pores due to stress is avoided.
Alternatively, the mass concentration of the aqueous dimethylacetamide solution in the primary coagulation bath may be any value between 70%, 75%, 80%, 85%, 90% and 70-90%, the mass concentration of the aqueous dimethylacetamide solution in the secondary coagulation bath may be any value between 40%, 45%, 50%, 55%, 60%, 65%, 70% and 40-70%, and the mass concentration of the aqueous dimethylacetamide solution in the tertiary coagulation bath may be any value between 10%, 15%, 20%, 25%, 30%, 35%, 40% and 10-40%; the mass concentration of the dimethylacetamide aqueous solution in the water washing system can be any value between 0.1%, 0.5%, 1%, 2%, 3% and 0-3%.
Preferably, the working temperature of the coagulating bath system and the water washing system is 25-65 ℃;
preferably, the coagulation bath system and the water washing system are both provided with ultrasonic devices.
The working temperatures of the coagulation bath system and the water washing system are selected to optimize the effect of phase separation; the separator having more excellent performance can be obtained by performing phase separation and water washing in the presence of ultrasonic waves.
Alternatively, the operating temperature of the coagulation bath system and the water washing system may be any value between 25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃ and 25-65 ℃.
Optionally, the water washing system further comprises drying, heat setting and rolling after treatment;
preferably, the drying includes hot air drying and drying roller drying;
preferably, the temperature of hot air for hot air drying is 50-80 ℃, and the temperature of a drying roller for drying by the drying roller is 40-60 ℃;
preferably, the heat setting is carried out in a mode of combining a carrier roller with air drying, and the temperature of the heat setting is 80-120 ℃;
preferably, the tension of the rolling is less than or equal to 5N/m.
Alternatively, the temperature of the hot air for hot air drying may be any value between 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃ and 50-80 ℃, and the temperature of the drying roller for drying may be any value between 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃ and 40-60 ℃; the heat setting temperature can be any value between 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 105 ℃, 110 ℃, 115 ℃, 120 ℃ and 80-120 ℃; the winding tension can be any value of 1N/m, 2N/m, 3N/m, 4N/m, 5N/m and less than or equal to 5N/m.
Through drying, heat setting and rolling and optimization of relevant parameters, a finished product with excellent performance can be obtained.
A lithium ion battery comprises the lithium ion battery diaphragm.
Compared with the prior art, the invention at least comprises the following beneficial effects:
1. the lithium ion battery diaphragm provided by the application is coated by adopting the oil system slurry, so that the caking property is strong; two ceramic combination modes are adopted to obtain a large-aperture deep-down hole with good permeability, so that a good ion transmission channel is provided for the rate discharge characteristic of the battery, and the failure of the battery caused by the compression of the membrane can be avoided; meanwhile, other pore-forming agents are prevented from being introduced, so that the side reaction of the battery caused by unclean pore-forming agent cleaning is avoided;
2. according to the preparation method of the lithium ion battery diaphragm, the obtained lithium ion battery diaphragm is high in liquid absorption and retention capacity and reasonable in aperture, and the cycle life of the battery is prolonged;
3. the lithium ion battery provided by the application has good cycle performance and high safety coefficient.
Drawings
To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, and it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope of the present invention.
FIG. 1 is a graph of specific discharge capacity test data;
FIG. 2 is a graph of cycle performance test data.
Detailed Description
The terms as used herein:
"prepared from … …" is synonymous with "comprising". The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.
The conjunction "consisting of … …" excludes any unspecified elements, steps or components. If used in a claim, the phrase is intended to claim as closed, meaning that it does not contain materials other than those described, except for the conventional impurities associated therewith. When the phrase "consisting of … …" appears in a clause of the subject matter of the claims rather than immediately after the subject matter, it defines only the elements described in the clause; other elements are not excluded from the claims as a whole.
When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or as a range of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when the range "1 ~ 5" is disclosed, the ranges described should be construed to include the ranges "1 ~ 4", "1 ~ 3", "1 ~ 2 and 4 ~ 5", "1 ~ 3 and 5", and the like. When a range of values is described herein, unless otherwise stated, the range is intended to include the endpoints thereof and all integers and fractions within the range.
In these examples, the parts and percentages are by mass unless otherwise indicated.
"part by mass" means a basic unit of measure indicating a mass ratio of a plurality of components, and 1 part may represent any unit mass, for example, 1g or 2.689 g. If we say that the part by mass of the component A is a part by mass and the part by mass of the component B is B part by mass, the ratio of the part by mass of the component A to the part by mass of the component B is a: b. alternatively, the mass of the A component is aK and the mass of the B component is bK (K is an arbitrary number, and represents a multiple factor). It is unmistakable that, unlike the parts by mass, the sum of the parts by mass of all the components is not limited to 100 parts.
"and/or" is used to indicate that one or both of the illustrated conditions may occur, e.g., a and/or B includes (a and B) and (a or B).
Embodiments of the present invention will be described in detail below with reference to specific examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
Example 1
After the base film is unreeled, a line bar is adopted to coat a layer of DMAC solvent, the base film is soaked in a diaphragm, the base film enters a double-sided coating system after being transparent, the double sides are coated simultaneously, the temperature of a coating material is 25 ℃, and the coating tension is 30N/m. Wherein the slurry comprises 90% of dimethylacetamide by mass, 4% of a copolymer of polyvinylidene fluoride and hexafluoropropylene by mass, and alpha-Al2O33% by mass, gamma-Al2O3The mass percentage is 3 percent. The coated membrane enters a primary coagulation bath system for phase separation, wherein the primary coagulation bath is a mixed solution of DMAC (dimethylacetamide) and water, the mass concentration of the DMAC water solution is 70%, and the temperature of the coagulation bath is 30 ℃; then entering a secondary coagulation bath, wherein the mass concentration of the DMAC aqueous solution is 50%, and the temperature of the coagulation bath is 30 ℃; then, the mixture enters a third coagulation bath, wherein the mass concentration of the DMAC aqueous solution is 40%, and the temperature of the coagulation bath is 30 ℃; then the mixture enters a water washing system, and the mass concentration of the DMAC aqueous solution is 3 percent. The temperature of the water washing system is controlled to be 25 ℃, and all the coagulating baths and the water washing system are equipped with ultrasound.
Then drying and heat setting the film, and rolling to obtain a product; the drying adopts a mode of air drying and roller drying, the film moves on a roller, the roller is a water passing roller, the temperature of the roller surface is controlled to be 50 ℃, meanwhile, hot air with the temperature of 50 ℃ is arranged on the periphery of the roller, and the hot air directly blows the film surface; the heat setting system adopts a carrier roller and air drying mode, wherein the air temperature is 80 ℃; the winding tension is 5N/m.
The obtained lithium ion battery diaphragm has the coating layer with the single-side thickness of 3 mu m, the base film with the thickness of 7 mu m and the total thickness of 13 mu m.
Example 2
After the base film is unreeled, a line bar is adopted to coat a layer of DMAC solvent, the base film is soaked in a diaphragm, the base film enters a double-sided coating system after being transparent, the double sides are coated simultaneously, the temperature of a coating material is 35 ℃, and the coating tension is 20N/m. Wherein the slurry comprises 80% of dimethylacetamide by mass, 10% of a copolymer of polyvinylidene fluoride and hexafluoropropylene by mass, and alpha-Al2O32% by mass, gamma-Al2O3The mass percentage is 8%. The coated membrane enters a primary coagulation bath system for phase separation, wherein the primary coagulation bath is a mixed solution of DMAC (dimethylacetamide) and water, the mass concentration of the DMAC water solution is 90%, and the temperature of the coagulation bath is 65 ℃; then entering a secondary coagulation bath, wherein the mass concentration of the DMAC aqueous solution is 70%, and the temperature of the coagulation bath is 50 ℃; then, the mixture enters a third coagulation bath, wherein the mass concentration of the DMAC aqueous solution is 30%, and the temperature of the coagulation bath is 40 ℃; then enters a water washing system, and the mass concentration of the DMAC aqueous solution is 2 percent. The temperature of the water washing system is controlled to be 35 ℃, and all the coagulating baths and the water washing system are equipped with ultrasound.
Then drying and heat setting the film, and rolling to obtain a product; the drying adopts a mode of air drying and roller drying, the film moves on a roller, the roller is a water-through roller, the temperature of the roller surface is controlled to be 60 ℃, meanwhile, 60 ℃ hot air is arranged on the periphery of the roller, and the hot air directly blows the film surface; the heat setting system adopts a carrier roller and air drying mode, wherein the air temperature is 100 ℃; the winding tension is 4N/m.
The obtained lithium ion battery diaphragm has the coating layer with the single-side thickness of 5 mu m, the base film with the thickness of 9 mu m and the total thickness of 19 mu m.
Example 3
After the base film is unreeled, a line bar is adopted to coat a layer of DMAC solvent, the base film is soaked in a diaphragm, the base film enters a double-sided coating system after being transparent, the double sides are coated simultaneously, the temperature of a coating material is 30 ℃, and the coating tension is 25N/m. Wherein the slurry comprises 93 percent of dimethylacetamide by mass, 2 percent of copolymer of polyvinylidene fluoride and hexafluoropropylene by mass, and alpha-Al2O33% by mass, gamma-Al2O3The mass percentage is 2%. The coated membrane enters a primary coagulation bath system for phase separation, the primary coagulation bath is a mixed solution of DMAC and water, wherein the mass concentration of the DMAC aqueous solution is 80%, and the temperature of the coagulation bath is 80%25 ℃; then entering a secondary coagulation bath, wherein the mass concentration of the DMAC aqueous solution is 40%, and the temperature of the coagulation bath is 25 ℃; then, the mixture enters a third coagulation bath, the mass concentration of the DMAC aqueous solution is 10%, and the temperature of the coagulation bath is 25 ℃; then entering a water washing system, wherein the mass concentration of the DMAC aqueous solution is 1%. The temperature of the water washing system is controlled to be 65 ℃, and all the coagulating baths and the water washing system are equipped with ultrasound.
Then drying and heat setting the film, and rolling to obtain a product; the drying adopts a mode of air drying and roller drying, the film moves on a roller, the roller is a water-through roller, the temperature of the roller surface is controlled to be 40 ℃, meanwhile, hot air with the temperature of 80 ℃ is arranged on the periphery of the roller, and the hot air directly blows the film surface; the heat setting system adopts a carrier roller and air drying mode, wherein the air temperature is 120 ℃; the winding tension is 3N/m.
The obtained lithium ion battery diaphragm has the coating single-side thickness of 4 mu m, the base film thickness of 8 mu m and the total thickness of 16 mu m.
Comparative example 1
Unlike example 1, the DMAC solvent was not applied prior to application of the slurry.
Comparative example 2
Unlike example 1, the slurry did not contain α -Al2O3Only gamma-Al2O3The mass percentage is 6%.
The separators obtained in example 1 and comparative examples 1 and 2 were tested for basic physical property indexes (multiple tests), and the results are shown in table 1 below:
TABLE 1 basic physical property index of separator
| Detecting items | Unit of | Example 1 | Comparative example 1 | Comparative example 2 | |
| Thickness of | μm | 17.2 | 17.5 | 19.3 | |
| Areal density | g/m2 | 9.5 | 9.6 | 10.2 | |
| Air permeability value | S/ |
200～220 | 230～250 | 200～220 | |
| Puncture strength | g | 500～520 | 500～520 | 510～530 | |
| Tensile Strength TD | MPa | 90～110 | 90～110 | 70～90 | |
| Tensile | MPa | 100～120 | 100～120 | 75～90 | |
| 130 ℃ @1h TD thermal shrinkage | ％ | 1.2 | 1.4 | 1.1 | |
| 130 ℃ @1h TD thermal shrinkage | ％ | 2.5 | 2.3 | 2.2 |
The diaphragm is prepared into a soft package battery for testing, wherein the battery capacity is 1Ah, the ternary nickel cobalt lithium manganate 523 type anode material, the artificial graphite cathode material, the lithium hexafluorophosphate electrolyte and the battery core adopt a winding type. Dry pressure conditions: 1kgf hot pressing for 3 seconds at 85 ℃. Hot pressing conditions after liquid injection: 0.7kgf hot pressing for 2 minutes at 65 ℃. The internal resistance, rate discharge ratio and cycle capacity retention rate of the battery were respectively tested, and the results are shown in table 2 below:
TABLE 2 Battery Performance index
| Detecting items | Unit of | Example 1 | Comparative example 1 | Comparative example 2 |
| Internal resistance of | mΩ | 52 | 53 | 56 |
| 0.5C specific discharge capacity | mAh/g | 156 | 157 | 153 |
| Specific discharge capacity of 3C | mAh/g | 135 | 130 | 124 |
| Specific discharge capacity of 5C | mAh/g | 109 | 106 | 99 |
| 3C/0.5C discharge ratio | ％ | 86.5 | 82.8 | 81 |
| Discharge ratio of 5C/0.5C | ％ | 69.9 | 67.5 | 64.7 |
| Capacity retention rate of 200 cycles | ％ | 93 | 91 | 84 |
In order to further prove the technical effect of the application, the adhesion, the liquid absorption rate, the rate discharge specific capacity and the cycle performance are tested.
And (3) testing the peel strength:
dry lamination is adopted, the dry lamination conditions are 85 ℃, 5 minutes and 0.7MPa, and the polar plate adopts the following components: LiCoO2Solef 5130, test objects were a common PE film and a separator prepared in example 1 of the present application, and the test results were: the peel strength of the general PE film was 4.34N/m, and the peel strength of the separator prepared in example 1 of the present application was 17.44N/m. Therefore, the lithium ion battery separator prepared by the method has high adhesion.
And (3) testing the liquid absorption rate:
and (3) taking a diaphragm with a certain area, weighing the mass difference before and after soaking of the electrolyte, and calculating the proportion of the diaphragm to absorb the electrode liquid. The conditions are that the soaking time is 2 hours, and the soaking is carried out at normal temperature. Test objects included PE-based membranes, aqueous PVDF membranes, and the oily PVDF membranes provided herein.
And (3) testing results: the liquid absorption rate of the PE base film is 80%, the liquid absorption rate of the water-based PVDF membrane is about 70%, and the liquid absorption rate of the oil-based PVDF membrane provided by the application is 90%.
And (3) testing the specific discharge capacity of the multiplying power:
the batteries manufactured by the separators obtained in example 1, comparative example 1 and comparative example 2 were charged and discharged at normal temperature rate, and the test results are shown in fig. 1.
As can be seen from fig. 1, the specific capacities of the batteries manufactured from the lithium ion battery separator obtained in example 1 of the present application were equal to those of comparative example 1 but superior to those of comparative examples 2, 3C and 5C, respectively, to those of comparative examples 1 and 2 at 0.5C and 1C. From this, it is understood that the selection of the ceramic has a great influence on the specific capacity.
And (3) testing the cycle performance:
the discharge capacity of the batteries manufactured in example 1, comparative example 1 and comparative example 2 was measured in relation to the number of cycles under normal temperature conditions, and the results are shown in fig. 2.
As can be seen from fig. 2, the cycle performance of the battery prepared in example 1 of the present application was superior to that of the batteries prepared in comparative examples 1 and 2.
The lithium ion battery diaphragm and the preparation method thereof have the advantages of strong cohesiveness, good permeability, high liquid absorption and retention capacity, and good safety of the prepared lithium ion battery.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Furthermore, those skilled in the art will appreciate that while some embodiments herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
Claims (10)
1. The lithium ion battery separator is characterized by comprising a base film and a coating coated on the surface of the base film;
the coating comprises the following raw materials in percentage by mass: 80-93% of dimethylacetamide, 2-10% of polyvinylidene fluoride and hexafluoropropylene copolymer, 2-15% of alpha crystal ceramic and 2-15% of gamma crystal ceramic.
2. The lithium ion battery separator according to claim 1, wherein the coating layer is provided on both surfaces of the base film in a length direction and a width direction;
preferably, the coating has a single-sided thickness of 3-5 μm.
3. The lithium ion battery separator according to claim 1, wherein the alpha crystalline ceramic is submicron particles and the gamma crystalline ceramic is nanoscale particles;
preferably, the alpha crystal ceramic is alpha-Al2O3The gamma crystal ceramic is gamma-Al2O3。
4. The lithium ion battery separator according to any of claims 1-3, wherein the base film is a polyolefin film having micropores;
preferably, the thickness of the base film is 7 to 9 μm.
5. A preparation method of the lithium ion battery separator according to any one of claims 1 to 4, characterized by comprising:
coating dimethylacetamide on the surface of a base film, mixing the raw materials to obtain slurry, and coating the slurry after the base film is transparent to obtain the coating;
and sequentially sending the base film coated with the coating into a coagulating bath system and a water washing system for treatment to obtain the lithium ion battery diaphragm.
6. The method of claim 5, wherein the temperature of the slurry is 25-35 ℃;
preferably, the coating tension of the base film is less than or equal to 30N/m when the slurry is coated.
7. The production method according to claim 5, wherein the coagulation bath system comprises a primary coagulation bath, a secondary coagulation bath and a tertiary coagulation bath which are arranged in this order;
preferably, the mass concentration of the dimethylacetamide aqueous solution in the primary coagulation bath is 70-90%, the mass concentration of the dimethylacetamide aqueous solution in the secondary coagulation bath is 40-70%, and the mass concentration of the dimethylacetamide aqueous solution in the tertiary coagulation bath is 10-40%;
preferably, the mass concentration of the dimethylacetamide aqueous solution in the water washing system is less than or equal to 3%.
8. The method for preparing the composite material according to claim 5, wherein the operating temperature of the coagulating bath system and the water washing system is 25-65 ℃;
preferably, the coagulation bath system and the water washing system are both provided with ultrasonic devices.
9. The preparation method according to any one of claims 5 to 8, wherein the water washing system treatment further comprises drying, heat setting and rolling;
preferably, the drying includes hot air drying and drying roller drying;
preferably, the temperature of hot air for hot air drying is 50-80 ℃, and the temperature of a drying roller for drying by the drying roller is 40-60 ℃;
preferably, the heat setting is carried out in a mode of combining a carrier roller with air drying, and the temperature of the heat setting is 80-120 ℃;
preferably, the tension of the rolling is less than or equal to 5N/m.
10. A lithium ion battery comprising the lithium ion battery separator according to any one of claims 1 to 4.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114843708A (en) * | 2022-07-04 | 2022-08-02 | 中材锂膜(宁乡)有限公司 | Porous diaphragm, preparation method thereof and electrochemical device |
Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101814590A (en) * | 2010-04-23 | 2010-08-25 | 湖南业翔晶科新能源有限公司 | Porous solid membrane used for lithium ion battery and production method thereof |
| CN102386357A (en) * | 2011-10-28 | 2012-03-21 | 浙江南都电源动力股份有限公司 | Preparation method for polymeric composite diaphragm of high-performance lithium ion battery |
| CN103947008A (en) * | 2011-11-15 | 2014-07-23 | 丰田自动车株式会社 | Non-aqueous electrolyte type secondary battery |
| CN104064707A (en) * | 2014-06-09 | 2014-09-24 | 东莞市魔方新能源科技有限公司 | Inorganic/organic composite membrane, preparation method of inorganic/organic composite membrane and lithium ion secondary battery containing membrane |
| CN104393215A (en) * | 2014-12-01 | 2015-03-04 | 天津工业大学 | Multilayer porous battery separator continuously varying with gradient in component proportion and preparation method thereof |
| CN104993082A (en) * | 2015-06-01 | 2015-10-21 | 常州大学 | Preparation method for nano-alumina particle modified ceramic diaphragm |
| CN105514328A (en) * | 2016-01-13 | 2016-04-20 | 浙江天能能源科技有限公司 | Ceramic diaphragm for lithium ion battery and preparation method of ceramic diaphragm |
| CN105845873A (en) * | 2016-05-18 | 2016-08-10 | 合肥国轩高科动力能源有限公司 | Polyvinylidene fluoride-coated lithium ion battery ceramic diaphragm and preparation method thereof |
| CN106784529A (en) * | 2016-12-27 | 2017-05-31 | 深圳中兴创新材料技术有限公司 | A kind of lithium ion battery separator and preparation method thereof |
| CN107895765A (en) * | 2017-10-13 | 2018-04-10 | 深圳市旭然电子有限公司 | Inorganic/organic composite porous barrier film, preparation method and its lithium ion battery |
| CN108807802A (en) * | 2018-08-20 | 2018-11-13 | 湖南烁普新材料有限公司 | Highly-breathable polymer-coated diaphragm and its preparation method and application |
| CN109004161A (en) * | 2018-06-20 | 2018-12-14 | 上海恩捷新材料科技股份有限公司 | Caking property battery diaphragm and preparation method thereof |
| 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 |
| CN109950452A (en) * | 2019-02-21 | 2019-06-28 | 威海星宜新材料科技有限公司 | A kind of lithium ion battery ceramics apply cloth diaphragm and preparation method thereof |
| CN110148699A (en) * | 2019-06-12 | 2019-08-20 | 扬州中锂新能源有限公司 | A kind of preparation process of the high-performance coating diaphragm of surface coating organic layer |
-
2019
- 2019-11-18 CN CN201911129230.7A patent/CN112909434A/en active Pending
Patent Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101814590A (en) * | 2010-04-23 | 2010-08-25 | 湖南业翔晶科新能源有限公司 | Porous solid membrane used for lithium ion battery and production method thereof |
| CN102386357A (en) * | 2011-10-28 | 2012-03-21 | 浙江南都电源动力股份有限公司 | Preparation method for polymeric composite diaphragm of high-performance lithium ion battery |
| CN103947008A (en) * | 2011-11-15 | 2014-07-23 | 丰田自动车株式会社 | Non-aqueous electrolyte type secondary battery |
| CN104064707A (en) * | 2014-06-09 | 2014-09-24 | 东莞市魔方新能源科技有限公司 | Inorganic/organic composite membrane, preparation method of inorganic/organic composite membrane and lithium ion secondary battery containing membrane |
| CN104393215A (en) * | 2014-12-01 | 2015-03-04 | 天津工业大学 | Multilayer porous battery separator continuously varying with gradient in component proportion and preparation method thereof |
| CN104993082A (en) * | 2015-06-01 | 2015-10-21 | 常州大学 | Preparation method for nano-alumina particle modified ceramic diaphragm |
| CN105514328A (en) * | 2016-01-13 | 2016-04-20 | 浙江天能能源科技有限公司 | Ceramic diaphragm for lithium ion battery and preparation method of ceramic diaphragm |
| CN105845873A (en) * | 2016-05-18 | 2016-08-10 | 合肥国轩高科动力能源有限公司 | Polyvinylidene fluoride-coated lithium ion battery ceramic diaphragm and preparation method thereof |
| CN106784529A (en) * | 2016-12-27 | 2017-05-31 | 深圳中兴创新材料技术有限公司 | A kind of lithium ion battery separator and preparation method thereof |
| CN107895765A (en) * | 2017-10-13 | 2018-04-10 | 深圳市旭然电子有限公司 | Inorganic/organic composite porous barrier film, preparation method and its lithium ion battery |
| CN109004161A (en) * | 2018-06-20 | 2018-12-14 | 上海恩捷新材料科技股份有限公司 | Caking property battery diaphragm and preparation method thereof |
| CN108807802A (en) * | 2018-08-20 | 2018-11-13 | 湖南烁普新材料有限公司 | Highly-breathable polymer-coated diaphragm and its preparation method and application |
| 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 |
| CN109950452A (en) * | 2019-02-21 | 2019-06-28 | 威海星宜新材料科技有限公司 | A kind of lithium ion battery ceramics apply cloth diaphragm and preparation method thereof |
| CN110148699A (en) * | 2019-06-12 | 2019-08-20 | 扬州中锂新能源有限公司 | A kind of preparation process of the high-performance coating diaphragm of surface coating organic layer |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114843708A (en) * | 2022-07-04 | 2022-08-02 | 中材锂膜(宁乡)有限公司 | Porous diaphragm, preparation method thereof and electrochemical device |
| CN114843708B (en) * | 2022-07-04 | 2022-10-11 | 中材锂膜(宁乡)有限公司 | Porous diaphragm, preparation method thereof and electrochemical device |
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