CN115764152A - Lithium battery diaphragm with polyketone coating - Google Patents
Lithium battery diaphragm with polyketone coating Download PDFInfo
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- CN115764152A CN115764152A CN202211339325.3A CN202211339325A CN115764152A CN 115764152 A CN115764152 A CN 115764152A CN 202211339325 A CN202211339325 A CN 202211339325A CN 115764152 A CN115764152 A CN 115764152A
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- polyketone
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- 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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Abstract
The invention discloses a lithium battery diaphragm with a polyketone coating, which is prepared by the steps of preparing a polyketone solution, casting a film, cleaning, reducing and hydroxylating the surface, physically hot-pressing and forming and the like, wherein the film is cast on the lithium battery diaphragm through the polyketone solution, and the hydroxylated polyketone film is reduced on the surface of the lithium battery diaphragm, so that the lithium battery diaphragm has good hydrophilicity and mechanical properties and excellent comprehensive performance, and the problems of low safety and high price of the existing diaphragm material are solved; the polyketone fibers can be mutually locked like a gear in the physical hot pressing process, the mechanical property and the coating effect are enhanced, the preparation process is simple, large-scale equipment is not needed, the performance cost is better, and the polyketone fibers are applied to lithium battery diaphragms and have wide application prospects in the aspects of organic solvent-resistant membranes, efficient oil-water separation and the like.
Description
Technical Field
The invention relates to the technical field of lithium batteries, in particular to a lithium battery diaphragm with a polyketone coating.
Background
The lithium ion battery is used as an energy storage product with extremely wide application, is inseparable from the production and life of people, mainly comprises a positive electrode, a negative electrode, a battery diaphragm, electrolyte and a battery shell, wherein the diaphragm is used as a core structure of the lithium battery and mainly shows two aspects, namely, an ion channel is provided for the migration of lithium ions, and safety guarantee is provided for the charge and discharge process of the lithium battery. The migration of lithium ions is mainly determined by the structure of the diaphragm and the micropore structure, and the structure can absorb and maintain a proper amount of electrolyte, so that the migration channel of the lithium ions stably exists; the diaphragm should have good insulating property to prevent the short circuit of the battery due to the contact of the positive electrode and the negative electrode, certain strength to deal with the winding and lamination actions during the assembly of the battery, and good heat resistance to keep certain dimensional stability under the high-temperature working condition.
The performance of the diaphragm determines the interface structure, internal resistance and the like of the battery, directly influences the capacity, circulation, safety performance and other characteristics of the battery, and the diaphragm with excellent performance plays an important role in improving the comprehensive performance of the battery. In the prior art, in order to improve the defects of the existing diaphragm coating material in safety and performance, three new materials, namely ceramic material, polyvinylidene fluoride and aramid fiber, can be used as coatings of lithium battery diaphragms, and the ceramic material can fall off after a long time and still has great potential safety hazards; the polyvinylidene fluoride can improve the combination degree of the positive electrode and the negative electrode of the lithium battery, but the safety is not improved, and the price of the polyvinylidene fluoride is increased by 5-6 times along with the enlargement of the scale of the electric automobile, so that the cost of the lithium battery coated with the polyvinylidene fluoride is increased more; aramid fiber is a new material developed in japan, has a high melting point, and can be coated on a diaphragm to improve the safety of a lithium battery, but the material is expensive and is not favorable for large-area market application. With the popularization of new energy vehicles, people have higher and higher requirements on lithium batteries, and a diaphragm coating material with higher safety and higher cost performance is urgently needed.
Disclosure of Invention
The invention aims to provide a lithium battery diaphragm with a polyketone coating, which is formed by casting a film on the lithium battery diaphragm through a polyketone solution and reducing a hydroxylated polyketone film on the surface, has good hydrophilicity and mechanical properties and excellent comprehensive performance, and solves the problems of low safety and high price of the existing diaphragm material.
The technical scheme adopted by the invention for realizing the purpose is as follows: a lithium battery separator having a polyketone coating, comprising the steps of:
step one, preparing polyketone solution
Dissolving 10wt% of polyketone powder in a resorcinol organic solvent, wherein the weight ratio of resorcinol to water is 65;
step two, polyketone solution film casting
Cooling the prepared polyketone homogeneous solution to room temperature, and coating the polyketone solution on a lithium battery diaphragm by using a stainless steel casting knife to form a polyketone film coating;
step three, cleaning
Immediately immersing the lithium battery diaphragm with the polyketone film coating into a methanol water solution at 23-27 ℃, wherein the weight ratio of methanol to water is 35;
step four, reducing the hydroxylated polyketone film on the surface
Firstly soaking the cleaned polyketone film in 0.1-0.2 wt% of sodium borohydride solution for 3-10min to obtain a surface reduction hydrophilic film, wherein the film is provided with hydroxyl;
step five, physical hot-press forming
And applying pressure of 10-12 Mpa to the dried lithium battery diaphragm at the temperature of 25-40 ℃, and compacting to obtain the lithium battery diaphragm with the polyketone coating, wherein the overall thickness of the diaphragm is 10-20 mu m.
And the polyketone solution casting film is coated on the diaphragm on one side or both sides in a slit extrusion coating mode or coated on both sides of the diaphragm in a dipping coating mode.
The concentrations of the acetone solution and the hexane solution for cleaning in the third step are both greater than 99%.
In the first step, an organic solvent is required to be selected to dissolve polyketone when preparing polyketone solution, the polyketone material is resistant to the organic solvent and can be dissolved in an acid-base solution, and the chemical property of resorcinol is similar to that of dibasic acid, so that resorcinol is selected to be used as the solvent to prepare the polyketone solution after being dissolved in water, and the prepared uniform solution has certain viscosity, can play a role of a binder and is beneficial to performing physical hot pressing to form a compact polyketone film coating.
In the third step, the original concentration of the methanol is more than 99 percent, the concentration of the methanol is 34 to 35 percent after the methanol is matched with water, and the propanol solution and the hexane solution with the concentration of more than 99 percent have strong capability of removing the organic solvent, fast air drying and volatilization and good cleaning effect.
In the fourth step, the prepared polyketone film is firstly soaked in a sodium borohydride solution to obtain a surface reduction water film, the concentration of the sodium borohydride solution is not high, and otherwise, the reducibility is not good.
The lithium battery diaphragm with the polyketone coating is formed by casting a film on the lithium battery diaphragm through a polyketone solution, and a hydroxylated polyketone film is reduced on the surface, so that the lithium battery diaphragm has good hydrophilicity and excellent comprehensive performance, polyketone fibers can be mutually locked like gears in the physical hot pressing process, the mechanical performance and the coating effect are enhanced, the preparation process is simple, large-scale equipment is not needed, and the performance cost is higher.
Detailed Description
The invention is further described in connection with the following embodiments without limiting its scope, and it will be apparent to those skilled in the art that modifications and variations can be made in the light of the following description, and all such modifications and variations are intended to fall within the scope of the appended claims.
Example 1
A lithium battery separator having a polyketone coating, comprising the steps of:
step one, preparing polyketone solution
Dissolving 10wt% of polyketone powder in a resorcinol organic solvent, wherein the weight ratio of resorcinol to water is 65;
step two, polyketone solution film casting
Cooling the prepared polyketone homogeneous solution to room temperature, coating the polyketone solution on a lithium battery diaphragm by using a stainless steel casting knife, and forming a polyketone film coating on one side of the lithium battery diaphragm;
step three, cleaning
Immediately immersing the lithium battery diaphragm with the polyketone film coating into a methanol water solution at 25 ℃, wherein the weight ratio of methanol to water is 35;
step four, reducing the hydroxylated polyketone film on the surface
Firstly soaking the cleaned polyketone film in 0.1 wt% sodium borohydride solution for 10min to obtain a surface reduction water film, wherein the film is provided with hydroxyl;
step five, physical hot-press forming
And applying 10Mpa pressure to the dried lithium battery diaphragm at the temperature of 25-40 ℃, and compacting to obtain the lithium battery diaphragm with the polyketone coating, wherein the overall thickness of the diaphragm is 12 microns.
Example 2
A lithium battery separator having a polyketone coating, comprising the steps of:
step one, preparing polyketone solution
Dissolving 10wt% of polyketone powder in a resorcinol organic solvent, wherein the weight ratio of resorcinol to water is 65;
step two, polyketone solution film casting
Cooling the prepared polyketone homogeneous solution to room temperature, coating the polyketone solution on a lithium battery diaphragm by using a stainless steel casting knife, and forming a polyketone film coating on two sides of the lithium battery diaphragm;
step three, cleaning
Immediately immersing the lithium battery diaphragm with the polyketone film coating into a methanol water solution at 26 ℃, wherein the weight ratio of methanol to water is 35;
step four, reducing the hydroxylated polyketone film on the surface
Soaking the cleaned polyketone film in 0.15 wt% sodium borohydride solution for 7min to obtain a surface reduction water film with hydroxyl on the film;
step five, physical hot-press forming
And applying 10Mpa pressure to the dried lithium battery diaphragm at the temperature of 25-40 ℃, and compacting to obtain the lithium battery diaphragm with the polyketone coating, wherein the overall thickness of the diaphragm is 15 mu m.
Example 3
A lithium battery separator having a polyketone coating, comprising the steps of:
step one, preparing polyketone solution
Dissolving 10wt% of polyketone powder in a resorcinol organic solvent, wherein the weight ratio of resorcinol to water is 65;
step two, polyketone solution film casting
Cooling the prepared polyketone homogeneous solution to room temperature, coating the polyketone solution on a lithium battery diaphragm by using a stainless steel casting knife, and forming a polyketone film coating on one side of the lithium battery diaphragm;
step three, cleaning
Immediately immersing the lithium battery diaphragm with the polyketone film coating into a methanol water solution at 24 ℃, wherein the weight ratio of methanol to water is 35;
step four, reducing the hydroxylated polyketone film on the surface
Firstly soaking the cleaned polyketone film in 0.2wt% sodium borohydride solution for 5min to obtain a surface reduction water film, wherein the film is provided with hydroxyl;
step five, physical hot-press forming
And applying pressure of 12Mpa to the dried lithium battery diaphragm at the temperature of 25-40 ℃, and compacting to obtain the lithium battery diaphragm with the polyketone coating, wherein the whole thickness of the diaphragm is 13 mu m.
Tests prove that the porosity of the polyketone coating diaphragm prepared in the embodiment 1-3 of the lithium battery diaphragm with the polyketone coating is 40% -70%, the liquid absorption rate of the electrolyte is up to more than 80%, the lithium battery diaphragm can resist the high temperature of 200 ℃, the thickness of the polyketone coating on the diaphragm is about 12 mu m, and the performance indexes are shown in Table 1.
TABLE 1 Performance index of polyketone membranes
Claims (4)
1. A lithium battery separator having a polyketone coating layer, comprising the steps of:
step one, preparing polyketone solution
Dissolving 10wt% of polyketone powder in a resorcinol organic solvent, wherein the weight ratio of resorcinol to water is 65;
step two, polyketone solution film casting
Cooling the prepared polyketone homogeneous solution to room temperature, and coating the polyketone solution on a lithium battery diaphragm by using a stainless steel casting knife to form a polyketone film coating;
step three, cleaning
Immediately immersing the lithium battery diaphragm with the polyketone film coating into a methanol water solution at 23-27 ℃, wherein the weight ratio of methanol to water is 35;
step four, reducing the hydroxylated polyketone film on the surface
Firstly soaking the cleaned polyketone film in 0.1-0.2 wt% of sodium borohydride solution for 3-10min to obtain a surface reduction hydrophilic film, wherein the film is provided with hydroxyl;
step five, physical hot-press forming
And applying pressure of 10-12 Mpa to the dried lithium battery diaphragm at the temperature of 25-40 ℃, and compacting to obtain the lithium battery diaphragm with the polyketone coating.
2. The lithium battery separator with a polyketone coating as claimed in claim 1, wherein the step-two polyketone solution cast film is coated on one side or both sides of the separator by a slit extrusion coating method, or coated on both sides of the separator by a dip coating method.
3. The lithium battery separator with polyketone coating as in claim 1, wherein the acetone solution and the hexane solution for cleaning in step three each have a concentration of >99%.
4. The lithium battery separator with a polyketone coating layer as claimed in claim 1, wherein the overall thickness of the separator with a polyketone coating layer is 10 to 20 μm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211339325.3A CN115764152A (en) | 2022-10-29 | 2022-10-29 | Lithium battery diaphragm with polyketone coating |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211339325.3A CN115764152A (en) | 2022-10-29 | 2022-10-29 | Lithium battery diaphragm with polyketone coating |
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| CN115764152A true CN115764152A (en) | 2023-03-07 |
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| CN202211339325.3A Pending CN115764152A (en) | 2022-10-29 | 2022-10-29 | Lithium battery diaphragm with polyketone coating |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116143355A (en) * | 2023-04-20 | 2023-05-23 | 北京科力丹迪技术开发有限责任公司 | Three-phase separator with good stability and use method thereof |
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2022
- 2022-10-29 CN CN202211339325.3A patent/CN115764152A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116143355A (en) * | 2023-04-20 | 2023-05-23 | 北京科力丹迪技术开发有限责任公司 | Three-phase separator with good stability and use method thereof |
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