CN112072054A - Battery diaphragm and preparation method and application thereof - Google Patents
Battery diaphragm and preparation method and application thereof Download PDFInfo
- Publication number
- CN112072054A CN112072054A CN202010984934.9A CN202010984934A CN112072054A CN 112072054 A CN112072054 A CN 112072054A CN 202010984934 A CN202010984934 A CN 202010984934A CN 112072054 A CN112072054 A CN 112072054A
- Authority
- CN
- China
- Prior art keywords
- battery
- diaphragm
- zirconium
- layer
- base layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Cell Separators (AREA)
Abstract
The invention discloses a battery diaphragm and a preparation method and application thereof. The battery separator includes: the diaphragm comprises a diaphragm base layer, a first zirconium oxide fiber layer and/or a second zirconium oxide fiber layer, wherein the first zirconium oxide fiber layer is positioned on one side of the diaphragm base layer, which faces to a positive plate; the second zirconium dioxide fiber layer is positioned on one side of the diaphragm base layer, which faces the negative plate. The battery diaphragm not only has good mechanical property and piercing strength, but also has good uniformity, can effectively solve the problem that a ceramic coating is easy to fall off, and can obviously improve the safety performance, the electrochemical performance and the service life of the battery when being used in the battery.
Description
Technical Field
The invention belongs to the field of batteries, and particularly relates to a battery diaphragm and a preparation method and application thereof.
Background
With the global energy crisis becoming more severe and the environmental problems becoming more severe, the replacement of fossil fuels by renewable energy sources is becoming a trend. Lithium ion battery with high voltage, high specific energy and long service lifeThe life and the like, and become the most favored secondary battery. Lithium ion batteries generally consist of a positive electrode, a negative electrode, a separator and an electrolyte. The separator plays a crucial role in a lithium ion battery as one of key components of the lithium ion battery, and the lithium ion battery mainly depends on the movement of lithium ions between a positive electrode and a negative electrode to work. During charging and discharging, Li+Li being inserted and extracted back and forth between two electrodes, i.e. during charging+The lithium ion battery is extracted from the positive electrode and is inserted into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge. As a key material of the lithium battery, the diaphragm plays a role in isolating electrons, prevents direct contact of a positive electrode and a negative electrode, allows lithium ions in electrolyte to freely pass through, and plays a vital role in guaranteeing safe operation of the battery. However, in order to meet the requirements for high mass energy density and volume energy density, the requirements for the diaphragm are becoming more and more strict, and therefore, the development of a diaphragm having excellent performance is being urgently required.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, the invention aims to provide a battery diaphragm and a preparation method and application thereof. The battery diaphragm not only has good mechanical property and piercing strength, but also has good uniformity, can effectively solve the problem that a ceramic coating is easy to fall off, and can obviously improve the safety performance, the electrochemical performance and the service life of the battery when being used in the battery.
The present application is primarily based on the following problems:
at present, a common diaphragm in a lithium ion battery is a polyolefin diaphragm mainly made of PE and PP or a diaphragm coated with ceramic, that is, a mixed slurry of ceramic powder, a binder and a solvent is coated on a diaphragm substrate to form a ceramic coating, however, ceramic ions coated on the surface of the diaphragm are easy to fall off, particularly in a cell winding process, the falling of the ceramic powder not only affects the uniformity of the diaphragm, but also affects the insertion and the separation of lithium ions, and the puncture strength of the diaphragm, and the like, so that the capacity, the internal resistance, the rate capability, the cycle service life, the safety performance and the like of the battery are directly affected, and with the gradual increase of energy density, the problem of the safety of a cell is more serious, and therefore, the improvement of the mechanical properties, the tensile strength, the puncture strength and the like.
To this end, according to a first aspect of the invention, the invention proposes a battery separator. According to an embodiment of the present invention, the battery separator includes: the diaphragm comprises a diaphragm base layer, a first zirconium oxide fiber layer and/or a second zirconium oxide fiber layer, wherein the first zirconium oxide fiber layer is positioned on one side of the diaphragm base layer, which faces to a positive plate; the second zirconium dioxide fiber layer is positioned on one side of the diaphragm base layer, which faces the negative plate.
According to the battery diaphragm of the embodiment of the invention, compared with the method that the ceramic coating is formed on the diaphragm base layer by taking the ceramic powder as the raw material or the ceramic powder and the polymer are blended and spun and the composite ceramic layer is formed on the diaphragm base layer, the fibrous zirconia is taken as the raw material to form the fibrous layer on the diaphragm base layer, so that the uniformity of the battery diaphragm can be further improved, the mechanical property and the puncture strength of the battery diaphragm are remarkably improved, the insertion and the extraction of lithium ions are facilitated, the safety performance, the electrochemical performance and the service life of the battery can be remarkably improved, and the problem that the safety performance, the electrochemical performance and the like of the battery are influenced due to the falling of the ceramic powder of the diaphragm in the prior art is effectively solved.
In addition, the battery separator according to the above embodiment of the present invention may further have the following additional technical features:
in some embodiments of the present invention, the separator base layer is formed using at least one selected from the group consisting of polypropylene, polyethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, polyester, glass fiber, aramid, and polyimide.
In some embodiments of the present invention, the membrane substrate is a single-layer substrate or a multi-layer substrate, each of the substrates being independently formed of a single material or a plurality of materials.
In some embodiments of the present invention, the thickness of the membrane substrate layer is 5 to 30 μm, and the thickness of the first zirconia fiber layer and the thickness of the second zirconia fiber layer are each independently 0.1 to 10 μm.
According to a second aspect of the invention, a method of making the above battery separator is provided. According to an embodiment of the invention, the method comprises:
(1) mixing a zirconium salt with an alcohol solvent to obtain a zirconium salt solution;
(2) dropwise adding a nitric acid solution into the zirconium salt solution under the conditions of heating and stirring for reaction so as to obtain sol;
(3) cooling the sol to normal temperature, and then carrying out centrifugal spinning to obtain gel fibers;
(4) roasting the gel fiber to obtain zirconia fiber;
(5) and mixing the zirconia fiber with a binder, an auxiliary agent and a solvent, coating the mixture on the diaphragm substrate, and drying to obtain the battery diaphragm with the zirconia fiber layer.
According to the method for preparing the battery diaphragm, the nitric acid solution is dripped into the alcoholic solution of the zirconium salt, the mixture is heated and stirred, then the temperature is reduced, gel with high viscosity can be formed, then centrifugal spinning and roasting are carried out on the gel, the zirconia fiber can be successfully prepared, finally the zirconia fiber is uniformly dispersed into the solvent by using the binder and the auxiliary agent and is bonded with the diaphragm base layer, and the battery diaphragm with better uniformity, mechanical property, piercing strength and structural stability can be obtained. Therefore, the method is simple in process, can effectively solve the problem that the safety performance, the electrochemical performance and the like of the battery are influenced due to the falling of the diaphragm ceramic powder in the prior art, and can improve the safety performance, the electrochemical performance and the service life of the battery when the prepared battery diaphragm is used in the battery.
In some embodiments of the present invention, in step (1), the zirconium salt is at least one selected from the group consisting of zirconium isopropoxide, zirconium n-butoxide and zirconium n-propoxide, and the organic solvent is at least one selected from the group consisting of ethanol, propanol, ethylene glycol, propylene glycol and butanol.
In some embodiments of the invention, in the step (2), the heating temperature is 60-85 ℃ and the reaction time is 2-4 h.
In some embodiments of the present invention, in the step (3), the sol has a viscosity of 500 to 3000Pa · s at a normal temperature.
In some embodiments of the invention, in the step (4), the temperature of the roasting treatment is 600-1000 ℃ and the time is 2-6 h.
In some embodiments of the invention, step (5) satisfies at least one of the following conditions: the binder is at least one selected from styrene-butadiene rubber, polyvinyl alcohol, hydroxymethyl cellulose salt, polyacrylic acid, polyacrylate and derivatives thereof, polyacrylonitrile, acrylate-acrylonitrile copolymer and polymethyl methacrylate; the auxiliary agent comprises a dispersing agent, and the dispersing agent is at least one selected from dodecyl sulfate, ammonium polyacrylate, methyl amyl alcohol, polyacrylamide, polyoxyethylene ether and oleamide; the auxiliary agent comprises a surfactant, and the surfactant is at least one selected from dodecyl benzene sulfonate, oleyl alcohol polyoxyethylene ether, oleate and stearate; the solvent is at least one selected from water, ethanol and NMP; in the mixed slurry formed by the zirconia fiber, the binder, the auxiliary agent and the solvent, the concentration of the zirconia fiber is 0.5-2 wt%; the coating mode is at least one selected from screen printing, extrusion coating and transfer coating; the mass ratio of the binder to the zirconia fiber is (0.01-10): 100, respectively; the drying temperature is 60-80 ℃, and the drying time is 30-120 min.
According to a third aspect of the present invention, a battery is provided. According to an embodiment of the invention, the battery has the battery diaphragm or the battery diaphragm obtained by the preparation method. Compared with the prior art, the battery has higher safety, better electrochemical performance and longer service life.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a flow chart of a method of making a battery separator according to one embodiment of the invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
According to a first aspect of the invention, a battery separator is provided. According to an embodiment of the present invention, the battery separator includes: the diaphragm base layer, the first zirconium oxide fiber layer and/or the second zirconium oxide fiber layer are/is arranged on one side, facing the positive plate, of the diaphragm base layer; the second zirconium dioxide fiber layer is positioned on one side of the diaphragm base layer facing the negative plate. The first zirconia fiber layer and the second zirconia fiber layer are both formed of fibrous zirconia. The battery diaphragm not only has good mechanical property and piercing strength, but also has good uniformity, can effectively solve the problem that a ceramic coating is easy to fall off, and can obviously improve the safety performance, the electrochemical performance and the service life of the battery when being used in the battery.
The battery separator according to the above-described embodiment of the present invention will be described in detail below.
According to an embodiment of the present invention, the material of the membrane substrate of the present invention is not particularly limited, and those skilled in the art can select the material according to actual needs. For example, the separator base layer may be formed using at least one selected from the group consisting of polypropylene, polyethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, polyester, glass fiber, aramid, and polyimide. Further, the separator base layer may be a single layer base layer or a multi-layer base layer, and each base layer may be independently formed of a single material or a plurality of materials, respectively.
According to still another embodiment of the present invention, the thickness of the separator base layer may be 5 to 30 μm, for example, 5 μm, 8 μm, 12 μm, 15 μm, 18 μm, 21 μm, 24 μm, 27 μm, or 30 μm, and the thicknesses of the first zirconia fiber layer and the second zirconia fiber layer may be 0.1 to 10 μm, for example, 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, respectively. The inventors have found that, although increasing the thickness of the separator can improve the puncture strength and the safety of the battery, but the capacity, rate capability and cycle performance of the battery are reduced, the mechanical property and puncture strength of the diaphragm can be remarkably improved by forming the zirconia fiber layer with the thickness in the range on at least one side of the diaphragm substrate, thereby being capable of leading the battery diaphragm to still keep better mechanical property and piercing strength on the basis of reducing the thickness, leading the thickness of the diaphragm base layer to be reduced to 5 mu m, being more beneficial to the full contact of the diaphragm and electrolyte, being capable of obviously improving the migration capability of lithium ions, therefore, when the diaphragm base layer with the structure and the thickness range is used in the battery, the risk that the diaphragm is pierced by lithium dendrites can be obviously reduced, the safety performance of the battery is obviously improved, and the rate capability and the cycle performance of the battery can be further improved.
According to still another embodiment of the present invention, the battery separator may include a separator base layer, a first zirconia fiber layer, and a second zirconia fiber layer, whereby the safety, electrochemical properties, and service life of the battery may be further improved.
In summary, according to the battery separator of the embodiments of the present invention, compared to forming a ceramic coating on a separator substrate using ceramic powder as a raw material or blending and spinning the ceramic powder and a polymer to form a composite ceramic layer on the separator substrate, in the present invention, fibrous zirconia is used as a raw material to form a fibrous layer on the separator substrate, which not only can further improve the uniformity of the battery separator, significantly improve the mechanical properties and puncture strength of the battery separator, but also is more beneficial to insertion and extraction of lithium ions, thereby significantly improving the safety performance, electrochemical performance and service life of the battery, and effectively solving the problem that the safety performance and electrochemical performance of the battery are affected by the falling of the ceramic powder of the separator in the prior art.
According to a second aspect of the invention, a method of making the above battery separator is provided. According to an embodiment of the invention, as shown in fig. 1, the method comprises:
s100: mixing zirconium salt with an alcohol solvent to obtain a zirconium salt solution; under the conditions of heating and stirring, the nitric acid solution is dripped into the zirconium salt solution for reaction to obtain sol
According to the embodiment of the invention, zirconium salt can be dissolved in an alcohol solvent in advance, then nitric acid solution is added as a catalyst, hydrolysis is started under the conditions of heating and stirring, and then high-viscosity sol is obtained through subsequent cooling. The inventors have found that hydrolysis by directly reacting a zirconium salt with water results in too rapid hydrolysis reaction to form a uniform and stable sol, and that reaction with an alcohol solvent instead of water as a solvent and nitric acid as an inhibitor can effectively control the hydrolysis reaction rate to maintain a stable state, thereby being more advantageous for obtaining a more uniform and stable sol. Among them, it is preferable to drop the nitric acid solution into the alcoholic solution of zirconium salt at a uniform speed, and if the nitric acid solution and the alcoholic solution of zirconium salt are directly mixed, the reaction speed is too fast, and it is difficult to obtain uniform and stable sol.
According to an embodiment of the present invention, the concentration of the nitric acid solution may be 0.5 to 1 wt%, and the inventors found that if the concentration of the nitric acid is too low, the hydrolysis reaction is too fast, and it is difficult to form uniform and stable sol and gel, and if the concentration of the nitric acid solution is too high, the reaction rate is too slow, and the reaction is incomplete, and by controlling the concentration of the nitric acid solution to be 0.5 to 1 wt%, the hydrolysis reaction can be controlled within a more stable rate, thereby being more beneficial to obtain uniform and stable sol and gel.
According to still another embodiment of the present invention, the zirconium salt in the present invention may preferably be at least one selected from the group consisting of zirconium isopropoxide, zirconium n-butoxide and zirconium n-propoxide, and the organic solvent may preferably be at least one selected from the group consisting of ethanol, propanol, ethylene glycol, propylene glycol and butanol. The selection of the raw materials allows the hydrolysis reaction to be controlled within a more stable rate so as to obtain uniform and stable gel fibers.
According to another embodiment of the present invention, the heating temperature may be 60 to 85 ℃, for example, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃ or 85 ℃, and the reaction time may be 2 to 4 hours, for example, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours. The inventor finds that when the nitric acid solution is dripped into the alcoholic solution of the zirconium salt, if the reaction temperature is too low or the reaction time is too short, the hydrolysis reaction is incomplete, and pure gel cannot be obtained; if the reaction temperature is too high or the reaction time is too long, the hydrolysis reaction speed is too high, and uniform fibrous gel cannot be formed; by controlling the reaction conditions, uniform and pure fiber gel can be obtained.
S200: cooling the sol to normal temperature, and performing centrifugal spinning to obtain gel fibers; roasting the gel fiber to obtain the zirconia fiber
According to an embodiment of the present invention, after the temperature of the sol is reduced to normal temperature, the viscosity of the sol is significantly increased, which is more favorable for spinning the sol to obtain fibrous zirconia. Among them, the viscosity of the sol at room temperature is preferably 500 to 3000Pa · s, which is more advantageous for the sol spinning molding.
According to another embodiment of the present invention, the temperature of the baking treatment may be 600 to 1000 ℃, for example, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, 950 ℃, or 1000 ℃, and the time may be set. The time is 2 to 6 hours, for example, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours or 6 hours. The inventors found that if the temperature of the calcination treatment is too low or the time is too short, the gel fibers cannot be completely decomposed; if the temperature of the roasting treatment is too high or the time is too long, the fiber structure is damaged, and a net structure cannot be formed to improve the mechanical and mechanical properties; by controlling the roasting conditions, the gel fiber can be fully decomposed, and the zirconia fiber with uniform diameter and higher purity can be obtained.
S300: mixing zirconia fiber with a binder, an auxiliary agent and a solvent, coating the mixture on a diaphragm substrate, and drying to obtain the battery diaphragm with the zirconia fiber layer
According to a specific embodiment of the present invention, the types of the binder and the solvent in the present invention are not particularly limited, and may be selected by those skilled in the art according to actual needs, for example, the binder may be at least one selected from styrene-butadiene rubber, polyvinyl alcohol, hydroxymethylcellulose salt, polyacrylic acid, polyacrylate and its derivatives, polyacrylonitrile, acrylate-acrylonitrile copolymer, and polymethylmethacrylate; the solvent may be at least one selected from water, ethanol, and NMP, and a volatile solvent is preferably used.
According to still another embodiment of the present invention, when the mixed slurry formed by mixing the zirconia fibers with the binder, the auxiliary agent and the solvent is coated on the separator base layer, the coating manner is not particularly limited, and may be selected by those skilled in the art according to actual needs, for example, the coating manner may be at least one selected from screen printing, extrusion coating and transfer coating.
According to still another embodiment of the present invention, when the zirconia fiber is mixed with the binder, the assistant and the solvent, the assistant may include a dispersant and/or a surfactant, wherein the dispersant may be at least one selected from the group consisting of lauryl sulfate, ammonium polyacrylate, methylpentanol, polyacrylamide, polyoxyethylene ether and oleamide; the surfactant may be at least one selected from dodecylbenzene sulfonate, oleyl alcohol polyoxyethylene ether, oleate and stearate, so that the dispersibility of the zirconia fiber in the mixed slurry may be further improved, thereby more advantageously obtaining a uniform and stable zirconia fiber layer. Furthermore, the mass ratio of the auxiliary agent to the zirconia fiber can be (0.5-1): 100, thereby being more advantageous in improving the dispersibility and stability of the zirconia fiber in the mixed slurry, and thus being more advantageous in forming a uniform zirconia fiber layer.
According to another embodiment of the present invention, the mass ratio of the binder to the zirconia fiber may be (0.01-10): 100, for example, (0.5-10)/100, (1-9)/100 or (1.5-8)/100, etc., and the inventors found that if the mass ratio of the binder to the zirconia fiber is too small, it is difficult to ensure the bonding strength between the separator base layer and the zirconia fiber layer, and if the amount of the binder is too large, the capacity, rate capability and cycle performance of the battery are affected.
According to another embodiment of the invention, after the zirconia fiber is mixed with the binder, the auxiliary agent and the solvent and coated on the diaphragm substrate, the mixture can be dried for 30-120 min at the temperature of 60-80 ℃, so that the drying efficiency and the drying effect can be further improved. Wherein the mixed slurry may be coated on one side or both sides of the separator base layer.
According to another embodiment of the present invention, the inventors found that compared with the method of co-spinning ceramic powder and polymer and forming a composite ceramic layer on a separator substrate, the method of the present invention is more favorable to form uniform and stable gel fibers by using hydrolysis reaction, and further obtains a zirconia fiber layer with higher purity, thereby not only better improving mechanical properties of the separator, but also improving sufficient contact between the separator and electrolyte, and further improving safety performance and electrochemical performance of the battery.
In summary, according to the method for preparing the battery separator of the embodiment of the invention, the nitric acid solution is dropped into the alcoholic solution of the zirconium salt, the mixture is heated and stirred, then the temperature is reduced, the gel with high viscosity can be formed, then the zirconium oxide fiber can be successfully prepared by centrifugal spinning and roasting, finally the zirconium oxide fiber is uniformly dispersed into the solvent by using the binder and the auxiliary agent and is bonded with the separator substrate, and the battery separator with good uniformity, mechanical property, puncture strength and structural stability can be obtained. Therefore, the method is simple in process, can effectively solve the problem that the safety performance, the electrochemical performance and the like of the battery are influenced due to the falling of the diaphragm ceramic powder in the prior art, and can improve the safety performance, the electrochemical performance and the service life of the battery when the prepared battery diaphragm is used in the battery. It should be noted that the features and effects described for the battery separator are also applicable to the method for preparing the battery separator, and are not described in detail herein.
According to a third aspect of the present invention, a battery is provided. According to an embodiment of the invention, the battery has the battery diaphragm or the battery diaphragm obtained by the preparation method. Compared with the prior art, the battery has higher safety, better electrochemical performance and longer service life. It should be noted that the features and effects described for the battery separator and the method for preparing the battery separator are also applicable to the battery, and are not described in detail herein.
The scheme of the invention will be explained with reference to the examples. It will be appreciated by those skilled in the art that the following examples are illustrative of the invention only and should not be taken as limiting the scope of the invention. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
Example 1
A preparation method of a lithium ion battery diaphragm specifically comprises the following steps:
(a) dissolving 500g of zirconium n-propoxide in ethanol, and uniformly mixing to obtain solution A; dissolving 50g of nitric acid in water to form solution B;
(b) dripping the B solution into the A solution, and continuously stirring at 75 ℃ to prepare sol;
(c) slowly reducing the temperature of the sol to normal temperature to obtain high-viscosity sol;
(d) adding the sol into a high-speed centrifuge, spinning to obtain zirconia gel fibers, and roasting at 800 ℃ for 2 hours to obtain zirconia fibers;
(e) uniformly mixing the obtained zirconia fiber, 25g of binder, 1.5g of dispersant and deionized water, and preparing mixed slurry of the zirconia fiber composite material under continuous stirring; wherein, the high molecular polymer binder is carboxymethyl cellulose, and the dispersant is dodecyl sulfate;
(f) and (e) coating the zirconium oxide fiber mixed slurry obtained in the step (e) on a single surface of a PE base film with the thickness of 12 microns in an extrusion coating mode, wherein the coating thickness is 2 microns, the coating speed is 20m/min, after the coating is finished, drying the PE base film with the coating at 80 ℃ for 40min to prepare a lithium ion battery diaphragm, and finally rolling the lithium ion battery diaphragm.
Example 2
A preparation method of a lithium ion battery diaphragm specifically comprises the following steps:
(a) dissolving 500g of n-butyl alcohol zirconium in ethanol, and uniformly mixing to obtain solution A; dissolving 50g of nitric acid in water to form solution B;
(b) dripping the B solution into the A solution, and continuously stirring at 75 ℃ to prepare sol;
(c) slowly reducing the temperature of the sol to normal temperature to obtain high-viscosity sol;
(d) adding the sol into a high-speed centrifuge, spinning to obtain zirconia gel fibers, and roasting at 800 ℃ for 2 hours to obtain zirconia fibers;
(e) uniformly mixing the obtained zirconia fiber, 25g of binder, 1.5g of dispersant and deionized water, and preparing mixed slurry of the zirconia fiber composite material under continuous stirring; wherein, the high molecular polymer binder is carboxymethyl cellulose, and the dispersant is dodecyl sulfate;
(f) and (e) coating the zirconium oxide fiber mixed slurry obtained in the step (e) on a single surface of a PE base film with the thickness of 12 microns in an extrusion coating mode, wherein the coating thickness is 2 microns, the coating speed is 20m/min, after the coating is finished, drying the PE base film with the coating at 80 ℃ for 40min to prepare a lithium ion battery diaphragm, and finally rolling the lithium ion battery diaphragm.
Comparative example 1
A preparation method of a lithium ion battery diaphragm specifically comprises the following steps:
uniformly mixing 160g of zirconia powder, 25g of binder, 1.5g of dispersant and deionized water, and preparing mixed slurry of the zirconia powder under continuous stirring; wherein, the binder is carboxymethyl cellulose, and the dispersant is dodecyl sulfate.
And (3) coating the mixed slurry on a single surface of a PE base film with the thickness of 12 microns, wherein the coating thickness is 2 microns, the coating speed is 20m/min, after the coating is finished, drying the PE base film with the coating at 80 ℃ for 40min to prepare a lithium ion battery diaphragm, and finally rolling the lithium ion battery diaphragm.
Example 3
A preparation method of a lithium ion battery diaphragm specifically comprises the following steps:
(a) dissolving 500g of zirconium n-propoxide in ethanol, and uniformly mixing to obtain solution A; dissolving 50g of nitric acid in water to form solution B;
(b) dripping the B solution into the A solution, and continuously stirring at 75 ℃ to prepare sol;
(c) slowly reducing the temperature of the sol to normal temperature to obtain high-viscosity sol;
(d) adding the sol into a high-speed centrifuge, spinning to obtain zirconia gel fibers, and roasting at 600 ℃ for 2 hours to obtain zirconia fibers;
(e) uniformly mixing the obtained zirconia fiber, 10g of binder, 1.5g of dispersant and deionized water, and preparing mixed slurry of the zirconia fiber composite material under continuous stirring; wherein, the high molecular polymer binder is carboxymethyl cellulose, and the dispersant is dodecyl sulfate;
(f) and (e) coating the zirconium oxide fiber mixed slurry obtained in the step (e) on the surfaces of the front surface and the back surface of the PE base film with the thickness of 10 micrometers in an extrusion coating mode, wherein the coating thickness is respectively and independently 2 micrometers, the coating speed is 20m/min, after the coating is finished, drying the PE base film with the coating at 80 ℃ for 40min to prepare the lithium ion battery diaphragm, and finally, rolling the lithium ion battery diaphragm.
Comparative example 2
A preparation method of a lithium ion battery diaphragm specifically comprises the following steps:
(a) dissolving 500g of zirconium n-propoxide in ethanol, and uniformly mixing to obtain solution A; dissolving 50g of nitric acid in water to form solution B;
(b) dripping the B solution into the A solution, and continuously stirring at 100 ℃ to prepare sol;
(c) slowly reducing the temperature of the sol to normal temperature to obtain high-viscosity sol;
(d) adding the sol into a high-speed centrifuge, spinning to obtain zirconia gel fibers, and roasting at 900 ℃ for 2 hours to obtain zirconia fibers;
(e) uniformly mixing the obtained zirconia fiber, 10g of binder, 1.5g of dispersant and deionized water, and preparing mixed slurry of the zirconia fiber composite material under continuous stirring; wherein, the high molecular polymer binder is carboxymethyl cellulose, and the dispersant is dodecyl sulfate;
(f) and (e) coating the zirconium oxide fiber mixed slurry obtained in the step (e) on a single surface of a PE base film with the thickness of 12 microns in an extrusion coating mode, wherein the coating thickness is 2 microns, the coating speed is 20m/min, after the coating is finished, drying the PE base film with the coating at 80 ℃ for 40min to prepare a lithium ion battery diaphragm, and finally rolling the lithium ion battery diaphragm.
Comparative example 3
A preparation method of a lithium ion battery diaphragm specifically comprises the following steps:
(a) dissolving 500g of zirconium n-propoxide in ethanol, and uniformly mixing to obtain solution A; dissolving 50g of nitric acid in water to form solution B;
(b) dripping the B solution into the A solution, and continuously stirring at 70 ℃ to prepare sol;
(c) slowly reducing the temperature of the sol to normal temperature to obtain high-viscosity sol;
(d) adding the sol into a high-speed centrifuge, spinning to obtain zirconia gel fibers, and roasting at 500 ℃ for 2 hours to obtain zirconia fibers;
(e) uniformly mixing the obtained zirconia fiber, 10g of binder, 1.5g of dispersant and deionized water, and preparing mixed slurry of the zirconia fiber composite material under continuous stirring; wherein, the high molecular polymer binder is carboxymethyl cellulose, and the dispersant is dodecyl sulfate;
(f) and (e) coating the zirconium oxide fiber mixed slurry obtained in the step (e) on a single surface of a PE base film with the thickness of 12 microns in an extrusion coating mode, wherein the coating thickness is 2 microns, the coating speed is 20m/min, after the coating is finished, drying the PE base film with the coating at 80 ℃ for 40min to prepare a lithium ion battery diaphragm, and finally rolling the lithium ion battery diaphragm.
Evaluation and conclusion:
tensile strength tests and puncture strength tests were performed on the lithium ion battery separators prepared in examples 1 to 3 and comparative examples 1 to 3 under the same conditions, and the results are shown in table 1. Wherein the test method refers to the polyethylene diaphragm for the GB-T36363-2018 lithium ion battery.
TABLE 1 test results of tensile strength test and puncture strength test
| Tensile Strength kgf/cm2 | Puncture Strength gf/cm2 | |
| Example 1 | 1830 | 825 |
| Example 2 | 1792 | 813 |
| Practice ofExample 3 | 2134 | 890 |
| Comparative example 1 | 920 | 395 |
| Comparative example 2 | 1230 | 572 |
| Comparative example 3 | 1326 | 614 |
It can be seen from the combination of examples 1 to 3 and comparative examples 1 to 3 and table 1 that, compared with single-sided coating, the preparation of the battery separator by coating zirconia fiber layers on both sides of the separator substrate can further improve the tensile strength and puncture strength of the battery separator on the basis of keeping the total thickness of the battery separator unchanged, thereby further improving the safety performance and electrochemical performance of the battery. In the preparation process of the battery diaphragm, the tensile strength and the puncture strength of the battery can be obviously influenced by overhigh heating temperature of the hydrolysis reaction or overlow subsequent roasting temperature, so that the performance of the battery is reduced. The battery diaphragm obtained by the preparation method of the embodiment of the invention has good tensile strength and puncture strength.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. A battery separator, comprising: the diaphragm comprises a diaphragm base layer, a first zirconium oxide fiber layer and/or a second zirconium oxide fiber layer, wherein the first zirconium oxide fiber layer is positioned on one side of the diaphragm base layer, which faces to a positive plate; the second zirconium dioxide fiber layer is positioned on one side of the diaphragm base layer, which faces the negative plate.
2. The battery separator according to claim 1, wherein the separator base layer is formed using at least one selected from the group consisting of polypropylene, polyethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, polyester, glass fiber, aramid, and polyimide.
3. The battery separator according to claim 2, wherein said separator base layer is a single-layer base layer or a multi-layer base layer, each of said base layers being independently formed of a single material or a plurality of materials.
4. The battery separator according to any one of claims 1 to 3, wherein the thickness of the separator base layer is 5 to 30 μm, and the thicknesses of the first zirconia fiber layer and the second zirconia fiber layer are each independently 0.1 to 10 μm.
5. A method of making the battery separator of any of claims 1-4, comprising:
(1) mixing a zirconium salt with an alcohol solvent to obtain a zirconium salt solution;
(2) dropwise adding a nitric acid solution into the zirconium salt solution under the conditions of heating and stirring for reaction so as to obtain sol;
(3) cooling the sol to normal temperature, and then carrying out centrifugal spinning to obtain gel fibers;
(4) roasting the gel fiber to obtain zirconia fiber;
(5) and mixing the zirconia fiber with a binder, an auxiliary agent and a solvent, coating the mixture on the diaphragm substrate, and drying to obtain the battery diaphragm with the zirconia fiber layer.
6. The method according to claim 5, wherein in step (1), the zirconium salt is at least one selected from the group consisting of zirconium isopropoxide, zirconium n-butoxide and zirconium n-propoxide, and the organic solvent is at least one selected from the group consisting of ethanol, propanol, ethylene glycol, propylene glycol and butanol.
7. The method according to claim 5 or 6, wherein in the step (2), the heating temperature is 60-85 ℃ and the reaction time is 2-4 h.
8. The method according to claim 7, wherein in the step (3), the sol has a viscosity of 500 to 3000 Pa-s at room temperature;
optionally, in the step (4), the temperature of the roasting treatment is 600-1000 ℃ and the time is 2-6 h.
9. The method according to claim 1 or 8, wherein step (5) satisfies at least one of the following conditions:
the binder is at least one selected from styrene-butadiene rubber, polyvinyl alcohol, hydroxymethyl cellulose salt, polyacrylic acid, polyacrylate and derivatives thereof, polyacrylonitrile, acrylate-acrylonitrile copolymer and polymethyl methacrylate;
the auxiliary agent comprises a dispersing agent, and the dispersing agent is at least one selected from dodecyl sulfate, ammonium polyacrylate, methyl amyl alcohol, polyacrylamide, polyoxyethylene ether and oleamide;
the auxiliary agent comprises a surfactant, and the surfactant is at least one selected from dodecyl benzene sulfonate, oleyl alcohol polyoxyethylene ether, oleate and stearate;
the solvent is at least one selected from water, ethanol and NMP;
in the mixed slurry formed by the zirconia fiber, the binder, the auxiliary agent and the solvent, the concentration of the zirconia fiber is 0.5-2 wt%;
the coating mode is at least one selected from screen printing, extrusion coating and transfer coating;
the mass ratio of the binder to the zirconia fiber is (0.01-10): 100, respectively;
the drying temperature is 60-80 ℃, and the drying time is 30-120 min.
10. A battery comprising the battery separator according to any one of claims 1 to 4 or the battery separator according to any one of claims 5 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010984934.9A CN112072054A (en) | 2020-09-18 | 2020-09-18 | Battery diaphragm and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010984934.9A CN112072054A (en) | 2020-09-18 | 2020-09-18 | Battery diaphragm and preparation method and application thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112072054A true CN112072054A (en) | 2020-12-11 |
Family
ID=73680711
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010984934.9A Pending CN112072054A (en) | 2020-09-18 | 2020-09-18 | Battery diaphragm and preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112072054A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024131601A1 (en) * | 2022-12-20 | 2024-06-27 | 宁德时代新能源科技股份有限公司 | Separator film, battery and electrical apparatus |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104681764A (en) * | 2015-02-10 | 2015-06-03 | 龙岩紫荆创新研究院 | Composite lithium ion battery ceramic diaphragm and preparation method thereof |
-
2020
- 2020-09-18 CN CN202010984934.9A patent/CN112072054A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104681764A (en) * | 2015-02-10 | 2015-06-03 | 龙岩紫荆创新研究院 | Composite lithium ion battery ceramic diaphragm and preparation method thereof |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024131601A1 (en) * | 2022-12-20 | 2024-06-27 | 宁德时代新能源科技股份有限公司 | Separator film, battery and electrical apparatus |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108878751B (en) | Conductive ceramic composite diaphragm and solid-state battery | |
| US11121356B2 (en) | Battery electrode plate preparation method | |
| CN110071293B (en) | Battery cell and battery, liquid-retaining coating and battery pole piece and preparation method thereof | |
| JP6585906B2 (en) | Lithium secondary battery separator, lithium secondary battery employing the same, and method for producing the same | |
| CN109103397A (en) | A kind of preparation method of lithium ion battery ceramic coating membrane | |
| CN107437603A (en) | Composite diaphragm for lithium ion battery and preparation method thereof and lithium ion battery | |
| EP3776691A1 (en) | Coating slurries for preparing separators, separators for electrochemical devices and preparation methods therefor | |
| CN108878733B (en) | Electrochemical device isolating membrane coating and preparation method and application thereof | |
| CN103367712A (en) | Preparation method of lithium ion battery coating pole piece | |
| CN110247009A (en) | A kind of anti-overcharge diaphragm and preparation method thereof and lithium ion battery | |
| CN109841785A (en) | A kind of battery diaphragm and preparation method thereof and the lithium ion battery comprising the diaphragm | |
| WO2020134763A1 (en) | Method for preparing battery separator with high ion conductivity and lithium ion battery containing same | |
| WO2019192475A1 (en) | Coating slurries for preparing separators, separators for electrochemical devices and preparation methods therefor | |
| CN115441048B (en) | Composite electrolyte with stable gradient distribution structure, battery and preparation method | |
| CN115548467A (en) | Electrode assembly, preparation method of electrode assembly and battery | |
| CN114927831A (en) | Composite diaphragm, preparation method thereof and lithium ion battery | |
| CN113394516A (en) | Lithium ion battery diaphragm, preparation method thereof and lithium ion battery | |
| CN113921986A (en) | Composite diaphragm and battery comprising same | |
| CN106848225B (en) | Coating material for improving safety of lithium ion battery, preparation method thereof and battery application | |
| CN112072054A (en) | Battery diaphragm and preparation method and application thereof | |
| CN110911619A (en) | Lithium battery diaphragm, preparation method thereof and lithium battery | |
| CN115939670A (en) | Composite diaphragm, preparation method thereof and lithium ion battery | |
| CN114883750A (en) | Composite diaphragm, preparation method thereof and lithium ion battery | |
| CN113013548A (en) | Montmorillonite modified lithium battery diaphragm and preparation method thereof | |
| CN110600659B (en) | Lithium ion battery diaphragm, preparation method thereof and lithium ion battery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20201211 |
|
| WD01 | Invention patent application deemed withdrawn after publication |