A kind of functional coating diaphragm and the battery containing the diaphragm
Technical field
The present invention relates to battery diaphragm field more particularly to a kind of functional coating diaphragm and contain the battery of the diaphragm.
Background technology
Lithium ion battery is mainly made of anode/negative material, electrolyte, diaphragm and battery housing material.Diaphragm
It is the important component of lithium ion battery, plays segmentation positive and negative electrode, prevent internal short-circuit of battery, allows electrolyte ion certainly
By passing through, the effect of charge discharge process is completed, performance determines the interfacial structure of battery, internal resistance etc., directly affects
The characteristics such as capacity, cycle performance and the security performance of battery, the diaphragm haveing excellent performance have the comprehensive performance for improving battery
Important role is known as " the third electrode of battery by industry.”
With the fast development of lithium ion battery, also higher and higher, adjoint energy density is required the energy density of battery
Raising, the comprehensive performance of battery is required to be promoted higher and higher, requires battery to have well while ensureing cycle life
Security performance.Diaphragm makees the important component of lithium ion battery, is played a key role to the performance of battery.Conventional is poly-
The satisfiable basic performance of alkene diaphragm, but wanting for its security performance far can not be met for high energy density cells
It asks, thus the functional diaphragm with high safety performance comes into being.
P is coated in membrane surface(VDF-HFP)It is a kind of common method improving diaphragm thermal stability and security performance,
Coordinate the good inorganic nanoparticles of thermal stability, absorbency and mechanical performance simultaneously, the heat that can greatly improve diaphragm is steady
Qualitative and chemical property.
Conventional P(VDF-HFP)Coat diaphragm generally use P(VDF-HFP)Solution is coated on polyalkene diaphragm table
Face has good thermal stability using diaphragm prepared by this method, while compared to common polyalkene diaphragm, coating P
(VDF-HFP)Diaphragm have stronger absorbent, the wellability of electrolyte can be improved.
Existing P(VDF-HFP)Diaphragm is coated compared to conventional polyolefin diaphragm with better thermal stability, but due to
It is limited to the security performance promotion of power battery, is used in greatly in small-sized 3C lithium ion batteries.With battery energy density
It is promoted, only coats P(VDF-HFP)Have been unable to meet the security performance requirement of power battery.
Invention content
In order to solve the above technical problem, the present invention provides a kind of functional coating diaphragm and contain the electricity of the diaphragm
Pond.The diaphragm of the present invention compares conventional oil system P(VDF-HFP)Diaphragm is coated, there is more excellent adhesive property and heat resistance,
Improve the security performance of battery.It applies in novel silicon carbon battery, both can effectively inhibit the expansion of silicon-carbon cathode, improve battery
Cycle life, while the security performance of high-energy density silicon-carbon battery core can be improved again.
The specific technical solution of the present invention is:A kind of functional coating diaphragm by polyolefin base material and is coated on described poly-
The coating of alkene substrate surface forms;The slurry for preparing of the coating includes aqueous polyvinylidene vinyl fluoride, inorganic nano ceramics
Grain and hydroxymethyl cellulose glue.
The present invention is directed to P(VDF-HFP)Deficiency existing for diaphragm is coated, is combined and is had using aqueous polyvinylidene vinyl fluoride binder
There is the inorganic nano ceramic particle of high-fire resistance to prepare functional coating diaphragm, the coated separator prepared using the program, not only
Has conventional oil system P(VDF-HFP)The performance of diaphragm is coated, while there is more excellent adhesive property and heat resistance, can be had
Effect inhibits falling off for diaphragm contraction at high temperature and coating, prevents the generation of thermal runaway, improves the security performance of battery.It answers
It in novel silicon carbon battery, both can effectively inhibit the expansion of silicon-carbon cathode, improve the cycle life of battery, while again can be with
Improve the security performance of high-energy density silicon-carbon battery core.
Preferably, the material of the polyolefin base material is one or both of polypropylene, polyethylene mixture.
Preferably, the thickness of the polyolefin base material is 15-25 microns.
Preferably, the two-sided of the polyolefin base material has been coated with coating.
Preferably, the thickness of the coating is 1.0-2.5 microns.
Preferably, the coating prepares inorganic nano ceramic particle in slurry, aqueous polyvinylidene vinyl fluoride, methylol
The mass ratio of cellulose glue is (94-95):(1.5-2.5):The solid content of (3-3.8), hydroxymethyl cellulose glue is
1.35wt%。
Preferably, preparing in slurry for the coating further includes silk-extract, wherein inorganic nano ceramic particle, water
Property Kynoar, hydroxymethyl cellulose glue, silk-extract mass ratio be (94-95):(1.5-2.5):(1.5-
2.5):The solid content of (1-2), hydroxymethyl cellulose glue are 1.35wt%;The silk-extract is made by following methods:It will
Silk Powder, which is added in boiling water, carries out boiling, solid-to-liquid ratio 1-2g/100mL, and boiling temperature is 98-100 DEG C, digestion time 1-
2h;Then the potassium carbonate that quality is 0.5-1.5 times of Silk Powder quality is added into boiling water, then reacts 0.5h at 60-70 DEG C,
It is filtered after reaction, takes filtrate, silk-extract is obtained after filtrate is spray-dried.
Silk-extract purity made from the above method is high, has outstanding caking property after being dissolved in water, with aqueous polyvinylidene fluorine
Be coated on membrane surface after ethylene and water compounding, coating after coating in subsequent drying, hot pressing, silk-extract with
Aqueous polyvinylidene vinyl fluoride act synergistically, coating and the conjugation of barrier film base material can be greatly improved, at the same can also enhance diaphragm with
The adhesiveness of pole piece reduces the gap between diaphragm and pole piece, not only reduces battery volume, but also can prevent cell expansion,
Enhance battery performance.
Preferably, the inorganic nano ceramic particle be nano-aluminium oxide and nano silicon dioxide in one kind or
Two kinds of mixtures, and the grain size of the inorganic nano ceramic particle is 400-800 nanometers.
Preferably, being used as the functional coating diaphragm using silicon carbon material as the lithium ion battery of negative electrode active material
Diaphragm.
Preferably, after battery injects electrolyte, battery is placed in 60-80 DEG C of environment, 1-2MPa is applied to battery
Pressure suppressed, the pressing time be 25-35 seconds.
After diaphragm is assemblied in battery, due to the property of coated substance on diaphragm of the present invention, coordinate the heat of special process
Pressure processing can effectively improve the cohesive force of diaphragm and positive/negative plate, especially soft-package battery, can effectively reduce diaphragm and pole
Gap between piece reduces the volume of battery, inhibits expansion of the battery in cyclic process, improves the service life of battery.
It is compared with the prior art, the beneficial effects of the invention are as follows:
1, functional diaphragm uses Water-Based Paint, relative to oil system P(VDF-HFP)Coated separator, water system PVDF binders
With stronger cohesive force, coating expansion rate is low, effectively inhibits the volume expansion of battery.
2, Water-Based Paint has lower internal resistance relative to oil system coating, can effectively improve the multiplying power and cyclicity of battery
Energy.
3, compared to the coating of oil system, the thickness of Water-Based Paint is easy to control, is easy to prepare microthin coating, is conducive to control battery
Thickness.
4, Water-Based Paint is environmentally friendly with respect to oil system coating, more environmentally friendly.
5, it applies in Soft Roll silicon-carbon battery, functional coating diaphragm can effectively inhibit the volume expansion of silicon-carbon cathode, carry
The cycle performance of high battery;Water-Based Paint inorganic nanoparticles have excellent heat resistance, can effectively inhibit diaphragm retracts,
The thermal stability for improving diaphragm, improves the security performance of battery core.
Description of the drawings
Fig. 1 is impedance and the cohesive force comparison diagram of the diaphragm and control sample of the embodiment of the present invention 1;
Fig. 2 is the expansion rate comparison diagram of the battery and control sample of the embodiment of the present invention 1.
Specific implementation mode
With reference to embodiment, the invention will be further described.
Embodiment 1
A kind of functional coating diaphragm is made of polyolefin base material and the coating for being coated on the polyolefin base material surface.
Wherein, the material of polyolefin base material is polypropylene;The thickness of polyolefin base material is 20 microns.
The two-sided of polyolefin base material has been coated with coating;The thickness of coating is 1.75 microns.The slurry for preparing of coating includes
Aqueous polyvinylidene vinyl fluoride, inorganic nano ceramic particle and hydroxymethyl cellulose glue.
Inorganic nano ceramic particle, aqueous polyvinylidene vinyl fluoride, hydroxymethyl cellulose glue mass ratio be 94.5:2:3.4.
The solid content of above-mentioned hydroxymethyl cellulose glue is 1.35wt%.
Above-mentioned inorganic nano ceramic particle is the nano-aluminium oxide that grain size is 500-600 nanometers.
The functional coating diaphragm is used as using silicon carbon material as cathode by a kind of battery containing functional coating diaphragm
The diaphragm of the lithium ion battery of active material.
After battery injects electrolyte, battery is placed in 70 DEG C of environment, the pressure for applying 1.5MPa to battery is pressed
System, pressing time are 30 seconds.
Embodiment 2
A kind of functional coating diaphragm is made of polyolefin base material and the coating for being coated on the polyolefin base material surface.
Wherein, the material of polyolefin base material is polyethylene;The thickness of polyolefin base material is 15 microns.
The two-sided of polyolefin base material has been coated with coating;The thickness of coating is 1.0 microns.The slurry for preparing of coating includes water
Property Kynoar, inorganic nano ceramic particle and hydroxymethyl cellulose glue.
Inorganic nano ceramic particle, aqueous polyvinylidene vinyl fluoride, hydroxymethyl cellulose glue mass ratio be 94: 2.5:
3.8。
The solid content of above-mentioned hydroxymethyl cellulose glue is 1.35wt%.
Above-mentioned inorganic nano ceramic particle is the nano silicon dioxide that grain size is 400-500 nanometers.
The functional coating diaphragm is used as using silicon carbon material as cathode by a kind of battery containing functional coating diaphragm
The diaphragm of the lithium ion battery of active material.
After battery injects electrolyte, battery is placed in 60 DEG C of environment, the pressure for applying 1MPa to battery is suppressed,
Pressing time is 35 seconds.
Embodiment 3
A kind of functional coating diaphragm is made of polyolefin base material and the coating for being coated on the polyolefin base material surface.
Wherein, the material of polyolefin base material is polyethylene;The thickness of polyolefin base material is 15 microns.
The two-sided of polyolefin base material has been coated with coating;The thickness of coating is 1.0 microns.The slurry for preparing of coating includes water
Property Kynoar, inorganic nano ceramic particle and hydroxymethyl cellulose glue.
Inorganic nano ceramic particle, aqueous polyvinylidene vinyl fluoride, hydroxymethyl cellulose glue mass ratio be 95: 1.5:3.
The solid content of above-mentioned hydroxymethyl cellulose glue is 1.35wt%.
Above-mentioned inorganic nano ceramic particle is the nano silicon dioxide that grain size is 400-500 nanometers.
The functional coating diaphragm is used as using silicon carbon material as cathode by a kind of battery containing functional coating diaphragm
The diaphragm of the lithium ion battery of active material.
After battery injects electrolyte, battery is placed in 60 DEG C of environment, the pressure for applying 1MPa to battery is suppressed,
Pressing time is 35 seconds.
Embodiment 4
A kind of functional coating diaphragm is made of polyolefin base material and the coating for being coated on the polyolefin base material surface.
Wherein, the material of polyolefin base material is the equal amount of mixture of polypropylene, polyethylene;The thickness of polyolefin base material is 25
Micron.
The two-sided of polyolefin base material has been coated with coating;The thickness of coating is 2.5 microns.The slurry for preparing of coating includes water
Property Kynoar, inorganic nano ceramic particle, silk-extract and hydroxymethyl cellulose glue.
Inorganic nano ceramic particle, aqueous polyvinylidene vinyl fluoride, hydroxymethyl cellulose glue, silk-extract mass ratio be
94:2.5:2.5:1,。
The solid content of above-mentioned hydroxymethyl cellulose glue is 1.35wt%.
Above-mentioned inorganic nano ceramic particle is the nano-aluminium oxide and nano silicon dioxide that grain size is 600-800 nanometers
Equal amount of mixture.
Above-mentioned silk-extract is made by following methods:Silk Powder is added in boiling water and carries out boiling, solid-to-liquid ratio 2g/
100mL, boiling temperature are 100 DEG C, digestion time 1h;Then the carbonic acid that quality is 1.5 times of Silk Powder quality is added into boiling water
Then potassium reacts 0.5h at 70 DEG C, is filtered after reaction, takes filtrate, silk extraction is obtained after filtrate is spray-dried
Object.
The functional coating diaphragm is used as using silicon carbon material as cathode by a kind of battery containing functional coating diaphragm
The diaphragm of the lithium ion battery of active material.
After battery injects electrolyte, battery is placed in 80 DEG C of environment, the pressure for applying 2MPa to battery is suppressed,
Pressing time is 25 seconds.
Embodiment 5
A kind of functional coating diaphragm is made of polyolefin base material and the coating for being coated on the polyolefin base material surface.
Wherein, the material of polyolefin base material is polypropylene;The thickness of polyolefin base material is 22 microns.
The two-sided of polyolefin base material has been coated with coating;The thickness of coating is 2 microns.The slurry for preparing of coating includes aqueous
Kynoar, inorganic nano ceramic particle, silk-extract and hydroxymethyl cellulose glue.
Inorganic nano ceramic particle, aqueous polyvinylidene vinyl fluoride, hydroxymethyl cellulose glue, silk-extract mass ratio be
95:1.5:1.5:2。
The solid content of above-mentioned hydroxymethyl cellulose glue is 1.35wt%.
Above-mentioned inorganic nano ceramic particle is the nano silicon dioxide that grain size is 500-600 nanometers.
Above-mentioned silk-extract is made by following methods:Silk Powder is added in boiling water and carries out boiling, solid-to-liquid ratio 1g/
100mL, boiling temperature are 98 DEG C, digestion time 2h;Then the carbonic acid that quality is 0.5 times of Silk Powder quality is added into boiling water
Then potassium reacts 0.5h at 60 DEG C, is filtered after reaction, takes filtrate, silk extraction is obtained after filtrate is spray-dried
Object.
The functional coating diaphragm is used as using silicon carbon material as cathode by a kind of battery containing functional coating diaphragm
The diaphragm of the lithium ion battery of active material.
After battery injects electrolyte, battery is placed in 70 DEG C of environment, the pressure for applying 1.5MPa to battery is pressed
System, pressing time are 30 seconds.
Embodiment 6
A kind of functional coating diaphragm is made of polyolefin base material and the coating for being coated on the polyolefin base material surface.
Wherein, the material of polyolefin base material is polyethylene;The thickness of polyolefin base material is 18 microns.
The two-sided of polyolefin base material has been coated with coating;The thickness of coating is 1.5 microns.The slurry for preparing of coating includes water
Property Kynoar, inorganic nano ceramic particle, silk-extract and hydroxymethyl cellulose glue.
Inorganic nano ceramic particle, aqueous polyvinylidene vinyl fluoride, hydroxymethyl cellulose glue, silk-extract mass ratio be
94.5:2:2:1.5),。
The solid content of above-mentioned hydroxymethyl cellulose glue is 1.35wt%.
Above-mentioned inorganic nano ceramic particle is the nano-aluminium oxide that grain size is 600-800 nanometers.
Above-mentioned silk-extract is made by following methods:Silk Powder is added in boiling water and carries out boiling, solid-to-liquid ratio is
1.5g/100mL, boiling temperature are 99 DEG C, digestion time 1.5h;Then it is 1 times of Silk Powder quality that quality is added into boiling water
Then potassium carbonate reacts 0.5h at 65 DEG C, is filtered after reaction, takes filtrate, silk is obtained after filtrate is spray-dried
Extract.
The functional coating diaphragm is used as using silicon carbon material as cathode by a kind of battery containing functional coating diaphragm
The diaphragm of the lithium ion battery of active material.
After battery injects electrolyte, battery is placed in 65 DEG C of environment, the pressure for applying 1.5MPa to battery is pressed
System, pressing time are 30 seconds.
Diaphragm impedance is tested with cohesive force
Impedance is carried out to the diaphragm of diaphragm and control sample 1, control sample 2 in embodiment 1 and cohesive force is tested, test condition
It is 50 DEG C, 40s, 3MPa.The wherein diaphragm of the diaphragm of control sample 1 and embodiment 1 is distinguished as no coating;Control sample 2 every
The coating that is distinguished as of film and the diaphragm of embodiment 1 is oil system P(VDF-HFP)Coating.
Testing result is as shown in Figure 1, the diaphragm of embodiment 1 and the cohesive force of cathode are far longer than control sample 1, control sample
2,;And the impedance of the diaphragm of embodiment 1 is only slightly greater than control sample 1, well below control sample 2.
Cell expansion rate is tested
To the diaphragm in embodiment 1 with the diaphragm of control sample 2 after being assembled in the battery communicated, carry out circulating battery after
Expansion rate is tested.
Fig. 2 is the X ray CT figure before and after circulating battery, as shown in Fig. 2, A is X ray CT figure before circulating battery in Fig. 2, is surveyed
It is 0% to obtain expansion rate, and after circulating battery same time, B is X ray CT figure after 2 circulating battery of control sample in Fig. 2, measures expansion rate
It is X ray CT figure after 1 circulating battery of embodiment for C in 4%, Fig. 2, it is 15% to measure expansion rate, therefore the expansion rate of embodiment 1 is remote
Far below the expansion rate of control sample 2, therefore security performance is more preferable.
Raw materials used in the present invention, equipment is unless otherwise noted the common raw material, equipment of this field;In the present invention
Method therefor is unless otherwise noted the conventional method of this field.
The above is only presently preferred embodiments of the present invention, is not imposed any restrictions to the present invention, every according to the present invention
Technical spirit still falls within the technology of the present invention side to any simple modification, change and equivalent transformation made by above example
The protection domain of case.