CN210778776U - Composite lithium ion battery diaphragm and lithium ion battery - Google Patents
Composite lithium ion battery diaphragm and lithium ion battery Download PDFInfo
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- CN210778776U CN210778776U CN201921574412.0U CN201921574412U CN210778776U CN 210778776 U CN210778776 U CN 210778776U CN 201921574412 U CN201921574412 U CN 201921574412U CN 210778776 U CN210778776 U CN 210778776U
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Abstract
The application provides a composite lithium ion battery diaphragm and a lithium ion battery, and relates to the field of lithium ion batteries. The composite lithium ion battery diaphragm comprises a first polyvinylidene fluoride layer, a first aramid fiber layer, a polyolefin layer, a second aramid fiber layer and a second polyvinylidene fluoride layer which are sequentially laminated; the first polyvinylidene fluoride layer, the first aramid fiber layer, the second aramid fiber layer and the second polyvinylidene fluoride layer are all provided with three-dimensional reticular holes, and the polyolefin layer is provided with micropores. A lithium ion battery comprises the composite lithium ion battery diaphragm. The application provides a lithium ion battery of compound lithium ion battery diaphragm preparation, can effectual solution current lithium battery diaphragm ceramic coating easily drop, can not resist high temperature and lithium ion battery because of the safety problem that the diaphragm caused, and this lithium ion battery diaphragm porosity is higher, and the electrolyte infiltration nature improves, and this diaphragm has good hot pressing cohesiveness with the battery polar plate simultaneously, is favorable to the promotion of battery form keeping and battery cycle performance.
Description
Technical Field
The application relates to the field of lithium ion batteries, in particular to a composite lithium ion battery diaphragm and a lithium ion battery.
Background
With the development of lithium ion batteries in the fields of electric vehicles, electronic consumer products, energy storage and the like, higher requirements are put forward on the comprehensive performance of the batteries, and the safety problem of the lithium ion batteries is particularly important, especially the problem of short circuit inside the batteries. The diaphragm is an indispensable component of the lithium ion battery, and has the functions of preventing the contact of the positive electrode and the negative electrode from generating short circuit and providing a channel for the migration of lithium ions in electrolyte.
The lithium ion battery separator which is most widely applied in the current market is a traditional polyolefin separator, and although the lithium ion battery separator has the advantages of good mechanical property, good chemical stability, low price and the like, the poor thermal stability of the lithium ion battery separator can influence the isolation between a positive electrode and a negative electrode, and even can cause safety accidents. In order to improve the comprehensive performance of the traditional polyolefin in the application of the lithium ion battery, researchers develop an organic-inorganic (ceramic) composite lithium ion battery diaphragm, and the common ceramic coating film in the domestic market is that a single-layer or double-layer water-soluble nano ceramic solution is directly coated on the polyolefin diaphragm and then dried at low temperature. Although the high temperature resistance of the diaphragm can be improved to a certain extent by the ceramic coating diaphragm, the polyolefin layer and the ceramic coating layer have weak interface bonding strength, so that the ceramic coating layer partially or largely falls off in the use process of the battery, the safety of the lithium ion battery diaphragm cannot be improved, and the battery performance of the lithium ion battery is influenced.
In view of this, the present application is specifically made.
SUMMERY OF THE UTILITY MODEL
A first object of the present application is to provide a composite lithium ion battery separator to solve the above problems.
A second object of the present application is to provide a lithium ion battery, which has good safety, and good battery form retention and cycle performance.
In order to achieve the above purpose, the following technical solutions are specifically adopted in the present application:
a composite lithium ion battery diaphragm comprises a first polyvinylidene fluoride layer, a first aramid fiber layer, a polyolefin layer, a second aramid fiber layer and a second polyvinylidene fluoride layer which are sequentially laminated;
the first polyvinylidene fluoride layer, the first aramid fiber layer, the second aramid fiber layer and the second polyvinylidene fluoride layer are all provided with three-dimensional reticular holes, and the polyolefin layer is provided with micropores.
Preferably, the first polyvinylidene fluoride layer and the second polyvinylidene fluoride layer are polyvinylidene fluoride electrostatic spinning layers;
preferably, the thickness of the polyvinylidene fluoride electrostatic spinning layer is 1-10 μm;
preferably, the polyvinylidene fluoride electrospun layer has a fiber diameter of 0.01-1 μm.
Alternatively, the thickness of the polyvinylidene fluoride electrospun layer can be any value between 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm and 1-10 μm; the polyvinylidene fluoride electrospun layer may have a fiber diameter of any one of 0.01 μm, 0.05 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm and 0.01-1 μm.
More preferably, the polyvinylidene fluoride electrospun layer has a porosity of 50-90%.
Optionally, the porosity of the polyvinylidene fluoride electrospun layer may be any value between 50%, 60%, 70%, 80%, 90% and 50% -90%.
Preferably, polyvinylidene fluoride used by the polyvinylidene fluoride electrostatic spinning layer is polyvinylidene fluoride homopolymer or copolymer of polyvinylidene fluoride and hexafluoropropylene;
preferably, the molecular weight of the polyvinylidene fluoride is 5000-1000000 Da.
Alternatively, the molecular weight of the polyvinylidene fluoride may be any one of 5000Da, 10000Da, 50000Da, 100000Da, 500000Da, 1000000Da and 5000-.
Preferably, the thickness of each of the first aramid layer and the second aramid layer is 0.5 to 10 μm.
Alternatively, the thicknesses of the first aramid layer and the second aramid layer may each independently be any value between 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, and 0.5-10 μm.
Preferably, the first aramid layer and the second aramid layer each have a porosity of 50% to 80%.
Optionally, the porosity of the first aramid layer and the second aramid layer may independently be any value between 50%, 60%, 70%, 80%, and 50% -80%.
Preferably, the aramid in the first and second aramid layers comprises one or more of meta-aramid, para-aramid, and modified aramid;
preferably, the molecular weight of the aramid fiber is 5000-.
Alternatively, the molecular weight of the aramid may be any value between 5000Da, 10000Da, 50000Da, 100000Da, 150000Da, 200000Da, and 5000-.
Preferably, inorganic ceramic particles are dispersed in three-dimensional mesh pores of the first aramid layer and the second aramid layer; the inorganic ceramic particles comprise one or more of aluminum oxide, silicon dioxide, titanium dioxide, zirconium dioxide, magnesium oxide, zinc oxide or barium oxide, and the particle size of the inorganic ceramic particles is 0.01-1 mu m.
Preferably, the polyolefin layer has a thickness of 5 to 40 μm;
preferably, the polyolefin layer has a porosity of 30% to 80%.
Alternatively, the thickness of the polyolefin layer may be any value between 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, and 5-40 μm; the polyolefin layer may have a porosity of any value between 30%, 40%, 50%, 60%, 70%, 80% and 30% to 80%.
Preferably, the polyolefin layer is made of one of PE, PP or PP/PE/PP three-layer composite film.
A lithium ion battery comprises the composite lithium ion battery diaphragm.
Compared with the prior art, the beneficial effect of this application includes:
the aramid fiber layer and the polyvinylidene fluoride layer are respectively arranged on the upper surface and the lower surface of the polyolefin film, the high-temperature resistance of the diaphragm can be improved due to the aramid fiber layer, the thermal shrinkage under the high-temperature condition is reduced, the polyvinylidene fluoride layer can be effectively bonded with the polar plate in a hot pressing mode, the bonding force between the diaphragm and the polar plate is improved, the hardness of the battery can be improved, the interface resistance is reduced, and the cycle performance and the service life of the lithium ion battery are improved; the aramid fiber layer and the polyvinylidene fluoride layer are provided with three-dimensional mesh holes, so that the wettability of the polyolefin diaphragm on electrolyte is improved, and the cycle performance of the lithium ion battery is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, 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, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a schematic structural diagram of a composite lithium ion battery separator provided in an embodiment of the present application.
Description of the main element symbols:
1-a first polyvinylidene fluoride layer; 2-a first aramid layer; 3-a polyolefin layer; 4-a second aramid layer; 5-a second polyvinylidene fluoride layer; 6-first three-dimensional reticulated pores; 7-second three-dimensional reticulated pores.
Detailed Description
Reference will now be made in detail to embodiments of the present application, 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 exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.
In the description of the present application, the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
The starting materials used in the present application are all commercially available starting materials. The aramid fiber is meta-aramid fiber sold by Futai and New materials GmbH, and the polyvinylidene fluoride material is powder sold by Solvay group under the trade designations of polyvinylidene fluoride 1015, 6010, 6020, etc., or powder sold by Achima group under the trade designations of polyvinylidene fluoride 711, 2801, LBG, etc.
Example 1
Referring to fig. 1, a composite lithium ion battery separator includes a first polyvinylidene fluoride layer 1, a first aramid layer 2, a polyolefin layer 3, a second aramid layer 4, and a second polyvinylidene fluoride layer 5, which are sequentially stacked; the first polyvinylidene fluoride layer 1 and the second polyvinylidene fluoride layer 5 are provided with first three-dimensional mesh holes 6, the first aramid fiber layer 2 and the second aramid fiber layer 4 are provided with second three-dimensional mesh holes 7, and the polyolefin layers are provided with micropores (not shown in the figure).
Wherein, the polyolefin layer 3 adopts a PE basal membrane with the thickness of 12 μm, and the porosity is 30 percent; the thickness of the first polyvinylidene fluoride layer 1 and the thickness of the second polyvinylidene fluoride layer 5 are both 10 mu m, the porosity is 50%, the molecular weight of the polyvinylidene fluoride is 5000-100000Da, and the diameter of the polyvinylidene fluoride fiber is 1 mu m; the thickness of the first aramid fiber layer 2 and the thickness of the second aramid fiber layer 4 are both 0.5 mu m, the porosity is 50%, and the molecular weight of the aramid fiber is 5000-100000 Da.
For example, the preparation method of the composite lithium ion battery separator provided by the present application may be:
pouring the prepared meta-aramid film casting solution (containing PEG2000) onto a PE base film (a polyolefin layer 3) with micropores, scraping the film by using a scraper, placing the film in a plasticizing bath for film formation by a phase conversion method to obtain a first aramid layer 2 (in the process, three-dimensional reticular holes 7 which are mutually communicated are formed in the first aramid layer 2), then soaking the first aramid layer 2 into a water bath, washing off the residual PEG2000, and performing the same coating step on the other surface after drying is completed to obtain a second aramid layer 4.
And (2) adding polyvinylidene fluoride into an N, N-dimethylacetamide (DMAc) solvent, and mechanically stirring in an oil bath until polyvinylidene fluoride is completely dissolved to obtain the polyvinylidene fluoride spinning solution. And injecting the prepared polyvinylidene fluoride spinning solution into a plastic injector, and spinning by using electrostatic spinning equipment, wherein the upper surface of the first aramid fiber layer 2 is used as a receiving layer. And drying to remove the redundant solvent to obtain a first polyvinylidene fluoride layer 1 with first three-dimensional mesh holes 6, and after drying is completed, performing the same electrostatic spinning step on the surface of the second aramid fiber layer 4 to obtain a second polyvinylidene fluoride layer 5, namely the composite lithium ion battery diaphragm provided by the application.
Example 2
Referring to fig. 1, a composite lithium ion battery separator includes a first polyvinylidene fluoride layer 1, a first aramid layer 2, a polyolefin layer 3, a second aramid layer 4, and a second polyvinylidene fluoride layer 5, which are sequentially stacked; the first polyvinylidene fluoride layer 1 and the second polyvinylidene fluoride layer 5 are provided with first three-dimensional mesh holes 6, the first aramid fiber layer 2 and the second aramid fiber layer 4 are provided with second three-dimensional mesh holes 7, and the polyolefin layers are provided with micropores (not shown in the figure).
Wherein, the polyolefin layer 3 adopts a PE basal membrane with the thickness of 9 μm, and the porosity is 40%; the thickness of the first polyvinylidene fluoride layer 1 and the thickness of the second polyvinylidene fluoride layer 5 are both 1 mu m, the porosity is 90%, the molecular weight of the polyvinylidene fluoride is 100000-500000Da, and the diameter of the polyvinylidene fluoride fiber is 0.01 mu m; the thickness of the first aramid fiber layer 2 and the second aramid fiber layer 4 are both 10 mu m, the porosity is 80%, and the molecular weight of the aramid fiber is 100000-200000 Da.
For example, the preparation method of the composite lithium ion battery separator provided by the present application may be:
pouring the prepared para-aramid film casting solution (containing alumina powder and lithium chloride) on a PE base film (a polyolefin layer 3) with micropores, scraping the film by using a scraper, placing the film in a plasticizing bath for film formation by a phase conversion method to obtain a first aramid layer 2 (in the process, three-dimensional reticular holes 7 which are mutually communicated are formed in the first aramid layer 2), then soaking the first aramid layer 2 in a water bath, washing off residual lithium chloride, and performing the same coating step on the other surface after drying is completed to obtain a second aramid layer 4.
And (2) adding polyvinylidene fluoride into an N, N-dimethylacetamide (DMAc) solvent, and mechanically stirring in an oil bath until polyvinylidene fluoride is completely dissolved to obtain the polyvinylidene fluoride spinning solution. And injecting the prepared polyvinylidene fluoride spinning solution into a plastic injector, and spinning by using electrostatic spinning equipment, wherein the upper surface of the first aramid fiber layer 2 is used as a receiving layer. And drying to remove the redundant solvent to obtain a first polyvinylidene fluoride layer 1 with first three-dimensional mesh holes 6, and after drying is completed, performing the same electrostatic spinning step on the surface of the second aramid fiber layer 4 to obtain a second polyvinylidene fluoride layer 5, namely the composite lithium ion battery diaphragm provided by the application.
Example 3
Referring to fig. 1, a composite lithium ion battery separator includes a first polyvinylidene fluoride layer 1, a first aramid layer 2, a polyolefin layer 3, a second aramid layer 4, and a second polyvinylidene fluoride layer 5, which are sequentially stacked; the first polyvinylidene fluoride layer 1 and the second polyvinylidene fluoride layer 5 are provided with first three-dimensional mesh holes 6, the first aramid fiber layer 2 and the second aramid fiber layer 4 are provided with second three-dimensional mesh holes 7, and the polyolefin layers are provided with micropores (not shown in the figure).
Wherein, the polyolefin layer 3 adopts a PP/PE/PP basal membrane (namely, the basal membrane which takes PE as a core material and is superposed with PP on the surface) with the thickness of 40 μm, and the porosity is 80 percent; the thickness of the first polyvinylidene fluoride layer 1 and the thickness of the second polyvinylidene fluoride layer 5 are both 5 mu m, the porosity is 60%, the molecular weight of the polyvinylidene fluoride is 200000-; the thickness of the first aramid fiber layer 2 and the thickness of the second aramid fiber layer 4 are both 5 micrometers, the porosity is 60 percent, and the molecular weight of the aramid fiber is 8000-150000 Da.
For example, the preparation method of the composite lithium ion battery separator provided by the present application may be:
pouring the prepared meta-aramid film casting solution (containing silicon oxide powder and PEG2000) onto a PP/PE/PP base film (a polyolefin layer 3) with micropores, scraping the film by using a scraper, then placing the film in a plasticizing bath for film formation by a phase conversion method to obtain a first aramid layer 2 (in the process, three-dimensional mesh holes 7 which are mutually communicated are formed in the first aramid layer 2), then soaking the first aramid layer 2 in a water bath to wash away the residual PEG2000, and performing the same coating step on the other surface after drying is completed to obtain a second aramid layer 4.
And (2) adding polyvinylidene fluoride into an N, N-dimethylacetamide (DMAc) solvent, and mechanically stirring in an oil bath until polyvinylidene fluoride is completely dissolved to obtain the polyvinylidene fluoride spinning solution. And injecting the prepared polyvinylidene fluoride spinning solution into a plastic injector, and spinning by using electrostatic spinning equipment, wherein the upper surface of the first aramid fiber layer 2 is used as a receiving layer. And drying to remove the redundant solvent to obtain a first polyvinylidene fluoride layer 1 with first three-dimensional mesh holes 6, and after drying is completed, performing the same electrostatic spinning step on the surface of the second aramid fiber layer 4 to obtain a second polyvinylidene fluoride layer 5, namely the composite lithium ion battery diaphragm provided by the application.
Example 4
Referring to fig. 1, a composite lithium ion battery separator includes a first polyvinylidene fluoride layer 1, a first aramid layer 2, a polyolefin layer 3, a second aramid layer 4, and a second polyvinylidene fluoride layer 5, which are sequentially stacked; the first polyvinylidene fluoride layer 1 and the second polyvinylidene fluoride layer 5 are provided with first three-dimensional mesh holes 6, the first aramid fiber layer 2 and the second aramid fiber layer 4 are provided with second three-dimensional mesh holes 7, and the polyolefin layers are provided with micropores (not shown in the figure).
Wherein, the polyolefin layer 3 adopts a PP basal membrane with the thickness of 20 μm, and the porosity is 50 percent; the thickness of the first polyvinylidene fluoride layer 1 and the thickness of the second polyvinylidene fluoride layer 5 are both 8 mu m, the porosity is 70%, the molecular weight of the polyvinylidene fluoride is 500000-1000000Da, and the diameter of the polyvinylidene fluoride fiber is 0.2 mu m; the thickness of the first aramid fiber layer 2 and the second aramid fiber layer 4 are both 8 mu m, the porosity is 70%, and the molecular weight of the aramid fiber is 50000-150000 Da.
For example, the preparation method of the composite lithium ion battery separator provided by the present application may be:
pouring the prepared meta-aramid film casting solution (containing titanium oxide powder and calcium chloride) onto a microporous PP (polypropylene) base film (a polyolefin layer 3), scraping the film by using a scraper, placing the film in a plasticizing bath for film formation by a phase conversion method to obtain a first aramid layer 2 (in the process, three-dimensional reticular pores 7 which are mutually communicated are formed in the first aramid layer 2), then soaking the first aramid layer 2 into a water bath, washing away residual calcium chloride, and performing the same coating step on the other surface after drying is completed to obtain a second aramid layer 4.
Adding polyvinylidene fluoride into N, N-dimethylacetamide (DMAc) solvent, and mechanically stirring in an oil bath until the polyvinylidene fluoride is completely dissolved to obtain the polyvinylidene fluoride spinning solution. And injecting the prepared polyvinylidene fluoride spinning solution into a plastic injector, and spinning by using electrostatic spinning equipment, wherein the upper surface of the first aramid fiber layer 2 is used as a receiving layer. And drying to remove the redundant solvent to obtain a first polyvinylidene fluoride layer 1 with first three-dimensional mesh holes 6, and after drying is completed, performing the same electrostatic spinning step on the surface of the second aramid fiber layer 4 to obtain a second polyvinylidene fluoride layer 5, namely the composite lithium ion battery diaphragm provided by the application.
Example 5
Referring to fig. 1, a composite lithium ion battery separator includes a first polyvinylidene fluoride layer 1, a first aramid layer 2, a polyolefin layer 3, a second aramid layer 4, and a second polyvinylidene fluoride layer 5, which are sequentially stacked; the first polyvinylidene fluoride layer 1 and the second polyvinylidene fluoride layer 5 are provided with first three-dimensional mesh holes 6, the first aramid fiber layer 2 and the second aramid fiber layer 4 are provided with second three-dimensional mesh holes 7, and the polyolefin layers are provided with micropores (not shown in the figure).
Wherein, the polyolefin layer 3 adopts a PE basal membrane with the thickness of 16 μm, and the porosity is 60 percent; the thickness of the first polyvinylidene fluoride layer 1 and the thickness of the second polyvinylidene fluoride layer 5 are both 3 mu m, the porosity is 80%, the molecular weight of the polyvinylidene fluoride is 800000-; the thickness of the first aramid fiber layer 2 and the thickness of the second aramid fiber layer 4 are both 3 mu m, the porosity is 55%, and the molecular weight of the aramid fiber is 8000-120000 Da.
For example, the preparation method of the composite lithium ion battery separator provided by the present application may be:
pouring the prepared modified aramid film casting solution (containing alumina powder and PEG2000) onto a PE base film (a polyolefin layer 3) with micropores, scraping the film by using a scraper, placing the film in a plasticizing bath for film formation by a phase conversion method to obtain a first aramid layer 2 (in the process, three-dimensional reticular holes 7 which are mutually communicated are formed in the first aramid layer 2), then soaking the first aramid layer 2 into a water bath, washing off the residual PEG2000, and performing the same coating step on the other surface after drying is completed to obtain a second aramid layer 4.
Adding the polyvinylidene fluoride and hexafluoropropylene copolymer into an N, N-dimethylacetamide (DMAc) solvent, and mechanically stirring in an oil bath until the polyvinylidene fluoride and hexafluoropropylene copolymer are completely dissolved to obtain the polyvinylidene fluoride and hexafluoropropylene copolymer spinning solution. And injecting the prepared polyvinylidene fluoride and hexafluoropropylene copolymer spinning solution into a plastic injector, and spinning by using electrostatic spinning equipment, wherein the upper surface of the first aramid fiber layer 2 is used as a receiving layer. And drying to remove the redundant solvent to obtain a first polyvinylidene fluoride layer 1 with first three-dimensional mesh holes 6, and after drying is completed, performing the same electrostatic spinning step on the surface of the second aramid fiber layer 4 to obtain a second polyvinylidene fluoride layer 5, namely the composite lithium ion battery diaphragm provided by the application.
It should be specifically noted that the preparation method provided by the present application is only an example and is not to be construed as a limitation of the present application; meanwhile, polyvinylidene fluoride, aramid fiber and polyolefin can be commercially available products, and the preparation method is introduced here for explaining the process of obtaining the composite lithium ion diaphragm. In addition, the thickness, the porosity and other parameters of the first polyvinylidene fluoride layer 1 and the second polyvinylidene fluoride layer 5 may be the same or different, and are not required to be completely consistent with each other, and the thickness, the porosity and other parameters of the first aramid layer 2 and the second aramid layer 4 may be the same or different, and are not required to be completely consistent with each other. The foregoing parameters are preferably consistent, but may be adjusted as desired.
The composite lithium ion battery diaphragm provided by the application is used for manufacturing a lithium ion battery.
The application provides a composite lithium ion battery diaphragm, 1. high temperature resistant nature is good: due to the aramid fiber layers on the upper surface and the lower surface of the polyolefin layer, the high-temperature resistance of the lithium ion battery diaphragm is improved, and the thermal shrinkage at high temperature is reduced; 2. the safety performance is good: the three-dimensional reticular pore structure of the aramid fiber layer can improve the safety performance of the lithium ion battery; 3. the porosity is high: the porosity of the aramid fiber layer and the porosity of the polyvinylidene fluoride electrostatic spinning layer are both higher, so that the wettability of the polyolefin diaphragm on electrolyte is improved, and the cycle performance of the lithium ion battery is improved; 4. high cohesiveness: the polyvinylidene fluoride electrostatic spinning layer can be effectively subjected to hot-pressing bonding with a polar plate, so that the bonding force between the diaphragm and the polar plate is improved, the hardness of the battery can be improved, the interface resistance is reduced, the cycle performance of the lithium ion battery is improved, and the service life of the lithium ion battery is prolonged.
The composite lithium ion battery diaphragm TD and MD150 ℃ thermal shrinkage provided by the application can be less than 5%, the ceramic coating diaphragm TD and MD150 ℃ thermal shrinkage in the prior art is more than 50%, the TMA film breaking temperature of the composite lithium ion battery diaphragm provided by the application is more than 300 ℃, the TMA film breaking temperature of the ceramic coating diaphragm in the prior art is less than 200 ℃, and the composite lithium ion battery diaphragm provided by the application greatly improves the temperature resistance and safety of the diaphragm. In addition, the bonding strength of the composite lithium ion battery diaphragm after hot pressing and the battery plate can be larger than 4N/m, the ceramic coated diaphragm in the prior art basically has no bonding force with the battery plate after hot pressing, the composite lithium ion battery diaphragm can be effectively bonded with the battery plate, and the hardness and form retention of the battery are improved. In addition, for current ceramic coating diaphragm and electrolyte contact angle be 28, the composite lithium ion battery diaphragm that this application provided is 17 with the electrolyte contact angle, be favorable to the infiltration of electrolyte, the battery capacity retention ratio after 300 cycles of battery that the composite lithium ion battery diaphragm that this application provided made simultaneously is 2% higher than with thickness ceramic coating diaphragm, the composite lithium ion battery diaphragm that this application provided has more excellent battery performance.
In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means 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 application. 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 application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.
Claims (11)
1. The composite lithium ion battery diaphragm is characterized by comprising a first polyvinylidene fluoride layer, a first aramid fiber layer, a polyolefin layer, a second aramid fiber layer and a second polyvinylidene fluoride layer which are sequentially laminated;
the first polyvinylidene fluoride layer, the first aramid fiber layer, the second aramid fiber layer and the second polyvinylidene fluoride layer are all provided with three-dimensional reticular holes, and the polyolefin layer is provided with micropores.
2. The composite lithium ion battery separator of claim 1, wherein the first and second polyvinylidene fluoride layers are polyvinylidene fluoride electrospun layers.
3. The composite lithium ion battery separator according to claim 2, wherein the thickness of the polyvinylidene fluoride electrospun layer is 1-10 μ ι η.
4. The composite lithium ion battery separator according to claim 2, wherein the polyvinylidene fluoride electrospun layer has a fiber diameter of 0.01-1 μm.
5. The composite lithium ion battery separator according to claim 2, wherein the polyvinylidene fluoride electrospun layer has a porosity of 50-90%.
6. The composite lithium ion battery separator of claim 1, wherein the first aramid layer and the second aramid layer each have a thickness of 0.5-10 μ ι η.
7. The composite lithium ion battery separator of claim 1, wherein the first aramid layer and the second aramid layer each have a porosity of 50-80%.
8. The composite lithium ion battery separator according to claim 1, wherein the polyolefin layer has a thickness of 5 to 40 μm.
9. The composite lithium ion battery separator according to claim 8, wherein the polyolefin layer has a porosity of 30% to 80%.
10. The composite lithium ion battery separator according to claim 8, wherein the polyolefin layer comprises one of PE, PP or PP/PE/PP three-layer composite membrane.
11. A lithium ion battery comprising the composite lithium ion battery separator according to any one of claims 1 to 10.
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| CN112290165A (en) * | 2020-11-05 | 2021-01-29 | 青岛蓝科途膜材料有限公司 | Lithium ion battery diaphragm, preparation method and lithium ion battery |
| CN112382828A (en) * | 2020-11-06 | 2021-02-19 | 东莞东阳光科研发有限公司 | Aramid fiber coated diaphragm and preparation method thereof |
| CN113675534A (en) * | 2021-08-23 | 2021-11-19 | 长园泽晖新能源材料研究院(珠海)有限公司 | Environment-friendly high-rate coating diaphragm |
| CN115101887A (en) * | 2022-07-22 | 2022-09-23 | 苏州太湖电工新材料股份有限公司 | Lithium ion battery diaphragm and preparation method and application thereof |
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| CN112290165A (en) * | 2020-11-05 | 2021-01-29 | 青岛蓝科途膜材料有限公司 | Lithium ion battery diaphragm, preparation method and lithium ion battery |
| CN112382828A (en) * | 2020-11-06 | 2021-02-19 | 东莞东阳光科研发有限公司 | Aramid fiber coated diaphragm and preparation method thereof |
| CN113675534A (en) * | 2021-08-23 | 2021-11-19 | 长园泽晖新能源材料研究院(珠海)有限公司 | Environment-friendly high-rate coating diaphragm |
| CN115101887A (en) * | 2022-07-22 | 2022-09-23 | 苏州太湖电工新材料股份有限公司 | Lithium ion battery diaphragm and preparation method and application thereof |
| CN115101887B (en) * | 2022-07-22 | 2024-03-01 | 苏州太湖电工新材料股份有限公司 | Lithium ion battery diaphragm and preparation method and application thereof |
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