CN102569695B - Preparation method for battery diaphragm - Google Patents
Preparation method for battery diaphragm Download PDFInfo
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- CN102569695B CN102569695B CN201010587484.6A CN201010587484A CN102569695B CN 102569695 B CN102569695 B CN 102569695B CN 201010587484 A CN201010587484 A CN 201010587484A CN 102569695 B CN102569695 B CN 102569695B
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- barrier film
- mineral oil
- substrate
- preparation
- battery diaphragm
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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Abstract
The invention provides a preparation method for a battery diaphragm. The preparation method for the battery diaphragm comprises the following steps in order: stirring, extruding, cooling and shaping, dual-direction stretching, extracting, transversely stretching and heat treating. A 6-micrometer ultra-thin battery diaphragm is prepared by the preparation method of the invention and has the advantages of high stability and long service life.
Description
Technical field
The present invention relates to a kind of preparation method, relate in particular to a kind of diaphragm of power lithium ion battery preparation method.
Background technology
Chargeable lithium ion secondary cell has the characteristic of high-energy-density, long circulation life, memory-less effect, has again the advantages such as safe, reliable and energy fast charging and discharging, thereby becomes the focus of novel power supply technical research in recent years.Because lithium ion battery is the free of contamination secondary cell of environmental type, meet the large growth requirement in countries nowadays energy environment protection aspect, increase sharply in the use amount of all trades and professions.Secondary lithium battery, except being widely used in the digital electronic goods such as the daily mobile phone of knowing, notebook computer and MP3, is also being brought into use aspect some high power batteries such as electric motor car, electric bicycle in recent years at present.From calendar year 2001, global lithium ion battery output is increasing progressively rapidly with annual 40% speed.
Barrier film is the important component part of lithium ion battery, and its performance has determined interfacial structure, the internal resistance etc. of battery, directly affects the characteristic such as capacity, cycle performance of battery.The barrier film of excellent performance has important effect to the combination property that improves battery.But preparation technology in the past can cause the inhomogeneous and membrane thickness unevenness of lithium ion battery separator pore-forming, thereby affect the quality of lithium ion battery.
China Patent No. is a kind of method that 200810042043.0 patent of invention has been announced lithium ion battery separator.The method step of this lithium ion battery separator is as follows:
One, by molecular weight be 7,000,000～1,000,000 ultra high molecular polyethylene, polynorbornene crosslinking agent, antioxidant and mineral oil by a certain percentage proportioning add the speed with 40～300rpm in mixer that raw material are fully stirred, wherein, the mass ratio of mineral oil and antioxidant is 1500～1600: 1, the mass ratio of mineral oil and ultra high molecular polyethylene is 4～8: 1, and the mass ratio of crosslinking agent and mineral oil is 1: 30～35;
Two, the mixture after being stirred by step 1 is dropped into double screw extruder and extrude continuously with 100～250 DEG C of heating, form substrate;
Three, carry out cooling forming with the cooling forming machine that the substrate that the speed of 2～20 ms/min makes to extrude from double screw extruder is 5～40 DEG C by temperature range;
Four, with the speed of 2～20 ms/min, substrate is carried out to horizontal stroke, vertical two-way simultaneous stretching by biaxial tension equipment, make substrate be drawn into barrier film, the membrane thicknesses of drawing and forming reaches 30～100 μ m, and barrier film acupuncture intensity is 300～600gf;
Five, be that the barrier film of 1500～2500 millimeters extracts the mineral oil in barrier film by extraction tank by width;
Six, barrier film is carried out the heat treatment of 1～3 minute at the temperature of 100～160 DEG C;
Seven, curling lithium battery diaphragm is cut packaging.
Said method has solved conventional art septation thickness low LCL evenly and the higher problem of cost, but also exists following defect:
The first, the polynorbornene crosslinking agent using in step 1 in said method, has increased cost of manufacture.
The second, after the mineral oil in said method extraction barrier film, extractant remaining on barrier film can not ensure sufficient volatilization, causes diaphragm quality to decline; Barrier film exists shape easily to occur the problem that barrier film deviation is larger simultaneously.
Three, in said method, the restriction of the term of reference of parameters is harsher, all higher to the requirement of raw material and production technology.
Summary of the invention
The object of the present invention is to provide a kind of battery diaphragm preparation method, the lithium ion battery separator substandard products incidence, production requirement and the higher defect of cost that make to solve prior art.
In order to achieve the above object, the invention provides a kind of battery diaphragm preparation method, comprise the following steps:
One, by ultra high molecular polyethylene, antioxidant and mineral oil by a certain percentage proportioning add in mixer raw material fully stirred;
Two, the mixture after being stirred by step 1 is dropped into double screw extruder heating and extrude continuously, form substrate;
Three, the substrate of extruding from double screw extruder carries out cooling forming through at least one group of chill roll group;
Four, by biaxial tension equipment, substrate is carried out to horizontal stroke, vertical two-way simultaneous stretching, make substrate be drawn into barrier film;
Five, use alkanes extractant, barrier film is extracted to the mineral oil in barrier film by extraction tank;
Six, the barrier film after extraction is passed through to transverse stretching equipment, barrier film is shaped, stretches, rectified a deviation, and guarantee the volatilization of the remaining extract on barrier film;
Seven, barrier film is heat-treated.
With respect to prior art, the present invention has the following advantages:
1, the present invention, in the use of having removed crosslinking agent aspect raw material practicality, has improved technical merit, provides cost savings.
2, diaphragm of power lithium ion battery preparation flow of the present invention has added the technique of barrier film cross directional stretch, barrier film has been carried out to the work of stretching, correction and sizing, makes remaining extractant be volatilized fully simultaneously, and has reduced the appearance of defect rate.
3, relax the limited range of partial parameters, reduced the requirement to raw material and production technology.
4, new invention selects range of choice wider at supra polymer.
5, can select the extractant that concentration is low to extract, reach same effect.
6, improved draw speed, can increase work efficiency, reduced costs.
7, use after transverse stretching equipment, heat treated temperature also will reduce, and heat treatment temperature can be reduced to 60～150 DEG C by original 100～160 DEG C, saves energy consumption, reduces costs.
8, by after adding cross directional stretch process to stretch to barrier film, can produce the wider lithium battery diaphragm of width.
Brief description of the drawings
Fig. 1 is a kind of lithium ion battery diaphragm producing system structure chart of the embodiment of the present invention;
Fig. 2 is transversal stretching device structure chart.
Embodiment
Embodiment 1, a kind of battery diaphragm in the present embodiment, espespecially a kind of lithium ion battery separator preparation method's step is as follows:
One, by ultra high molecular polyethylene, antioxidant and mineral oil by a certain percentage proportioning add in mixer raw material fully stirred, wherein, the mass ratio of mineral oil and antioxidant is 1000～2000: 1, and the mass ratio of mineral oil and ultra high molecular polyethylene is 2～10: 1.
The molecular weight of the molecule of the ultra high molecular polyethylene in the present embodiment is more than 1,000,000.
Two, the mixture after being stirred by step 1 is dropped into double screw extruder heating and extrude continuously, form substrate.
Here the screw diameter of double screw extruder is 10～150 millimeters, its extrusion capacity be greater than 200 kilograms per hour.
Three, the substrate of extruding from double screw extruder carries out cooling forming through one group of chill roll group;
Four, by biaxial tension equipment, substrate is carried out to horizontal stroke, vertical two-way simultaneous stretching, make substrate be drawn into barrier film, the membrane thicknesses of drawing and forming reaches 10～150 μ m.
Five, the high concentration alkanes extractant of use 80%～99.9%, the barrier film that is 1000～3000 by width extracts the mineral oil in barrier film by extraction tank, and one-step pore-creating.
Six, the barrier film after extraction is passed through to transverse stretching equipment, with the speed of 5～50 ms/min, barrier film is shaped, stretches, rectified a deviation, and guarantee the volatilization of the remaining extract on barrier film.
Seven, barrier film is carried out the heat treatment of 3～15 minutes.
In addition,, after the heat treatment of barrier film completing steps seven, also need finished product barrier film to carry out work curling, that cut and pack.
Method of the present invention can realize by following a kind of diaphragm of power lithium ion battery Preparation equipment, as shown in Figure 1, and its a kind of power lithium ion battery separator producing system structure chart that is the embodiment of the present invention.This power lithium ion battery separator producing system comprises agitating device 103, extrusion device 105, cooling forming device 107, two-way stretch device 109, extraction equipment 111, transversal stretching device 113, annealing device 115.And agitating device 103, extrusion device 105, cooling forming device 107, two-way stretch device 109, extraction equipment 111, transversal stretching device 113, annealing device 115 connect successively.
In the time of power lithium ion battery separator producing system work of the present invention, first a certain proportion of ultra high molecular polyethylene, antioxidant and mineral oil are added in agitating device 103 and fully stirred.Wherein, the mass ratio of mineral oil and antioxidant is 1000～2000: 1, and the mass ratio of mineral oil and ultra high molecular polyethylene is 2～10: 1.The molecular weight of ultra high molecular polyethylene is more than 1,000,000.The utilized viscosity grade of mineral oil is between 30～60.
After the abundant stirring of agitating device 103, its mixture is added to extrusion device 105 at ultra high molecular polyethylene, antioxidant and mineral oil, and heat and extrude continuously, form substrate, the thickness of this substrate is 0.1～15mm.Wherein extrusion device 105 can be double screw extruder, and its screw diameter is 10～150 millimeters, extrusion capacity be greater than 200 kilograms per hour.
Extrusion device 105 is extruded after substrate, and the substrate of extruding, by cooling forming device 107, is carried out to cooling forming to substrate.Cooling forming device 107 can be made up of six groups of refrigerating modules, and every pack module has two chill rolls, the temperature difference of every group of refrigerating module, and cooling forming can make in substrate ultra high molecular polyethylene non-crystallizable, reaches the object of film thickness homogeneous.
Substrate after cooling forming device 107 cooling formings, then by two-way stretch device 109 carry out horizontal stroke, vertical two-way simultaneous stretches, making substrate be drawn into thickness is 10～150 μ m.Two-way stretch device 109 stretches for transverse and longitudinal simultaneously, can, by regulating stretch ratio to regulate hot strength, can ensure that like this film thickness is even, and transverse and longitudinal stretch ratio can be adjusted according to thickness degree.
Barrier film, after two-way stretch device 109 drawing and formings, then carries out single extraction through extraction equipment 111, and extracts the mineral oil in barrier film.Extraction equipment 111 can be extraction tank.Extractant in extraction equipment 111 can be positive flow silane, normal heptane, carrene etc., and wherein the extractant of alkanes can make the mineral oil in barrier film separate out completely.
Barrier film, after extraction equipment 111 extractions, enters transversal stretching device 113.The strutting piece 1133 that transverse stretching equipment comprises clamping device 1131 in order to clamp the barrier film after extraction, make track 1132 that clamping device moves forward and clamping device and track are supported.When barrier film enters after transversal stretching device 113, left clamping unit 1131 and right clamping unit clamp the both sides of barrier film.After clamping, barrier film is along with clamping device 1131 travels forward with the speed of 5～50 ms/min under guide rail 1132 effects.Because becoming an oblique angle that is less than 5 ° with diaphragm movement direction, outwards departs from track 1132, along with travelling forward of barrier film, distance between left clamping unit 1131 and right clamping unit increases gradually, and barrier film is launched by cross directional stretch gradually, and this process has completed correction and the sizing of barrier film.Meanwhile, the length setting of guide rail is 20～30 meters, and the extractant remaining in the process of whole motion on barrier film can be volatilized more fully, is controlled better by the thickness homogeneity of cross directional stretch barrier film.
Finally by annealing device 115, it is carried out to heat treatment in 6～12 minutes.
As long as to barrier film after treatment carry out curling, cut and the operation such as packaging after just can obtain the finished product of diaphragm of power lithium ion battery.
With respect to prior art, the present invention has the following advantages:
1, the present invention, in the use of having removed crosslinking agent aspect raw material practicality, has improved technical merit, provides cost savings.
2, diaphragm of power lithium ion battery preparation flow of the present invention has added the technique of barrier film cross directional stretch, barrier film has been carried out to the work of stretching, correction and sizing, makes remaining extractant be volatilized fully simultaneously, and has reduced the appearance of defect rate.
3, relax the limited range of partial parameters, reduced the requirement to raw material and production technology.
4, new invention selects range of choice wider at supra polymer.
5, can select the extractant that concentration is low to extract, reach same effect.
6, stretch with the speed of 8～50 ms/min, can increase work efficiency, reduce costs.
7, use after transverse stretching equipment, heat treated temperature also will reduce, and heat treatment temperature is reduced to 60～150 DEG C by original 100～160 DEG C, saves energy consumption, reduces costs.
8, by after adding cross directional stretch process to stretch to barrier film, can produce the wider lithium battery diaphragm of width.
Disclosed is above only several specific embodiment of the present invention, but the present invention is not limited thereto, and the changes that any person skilled in the art can think of all should drop in protection scope of the present invention.
Claims (3)
1. a preparation method for battery diaphragm, is characterized in that, comprises the following steps:
One, by ultra high molecular polyethylene, antioxidant and mineral oil by a certain percentage proportioning add in mixer raw material fully stirred; Wherein, the molecular weight of ultra high molecular polyethylene is more than 1,000,000, and the mass ratio of mineral oil and antioxidant is 500～1800: 1, and the mass ratio of mineral oil and ultra high molecular polyethylene is 3～9: 1
Two, the mixture after being stirred by step 1 is dropped into double screw extruder heating and extrude continuously, form substrate;
Three, the substrate of extruding from double screw extruder carries out cooling forming through at least one group of chill roll group;
Four, by biaxial tension equipment, substrate is carried out to horizontal stroke, vertical two-way simultaneous stretching, make substrate be drawn into barrier film;
Five, use alkanes extractant, barrier film is extracted to the mineral oil in barrier film by extraction tank;
Six, the barrier film after extraction is passed through to transverse stretching equipment, barrier film is shaped, stretches, rectified a deviation, and guarantee the volatilization of the remaining extract on barrier film;
Seven, barrier film is heat-treated;
Wherein, the strutting piece that described transverse stretching equipment comprises clamping device in order to clamp the barrier film after extraction, make track that clamping device moves forward and clamping device and track are supported, clamping device comprises the left clamping unit and the right clamping unit that are positioned at barrier film both sides; Track length is 20～30 meters, and track becomes an oblique angle that is less than 5 ° outwards to depart from diaphragm movement direction.
2. battery diaphragm preparation method as claimed in claim 1, is characterized in that, the membrane thicknesses of step 4 drawing and forming is 10～150 μ m.
3. battery diaphragm preparation method as claimed in claim 1, is characterized in that, the concentration of the alkanes extractant that step 5 is used is 80%～99.9%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201010587484.6A CN102569695B (en) | 2010-12-14 | 2010-12-14 | Preparation method for battery diaphragm |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010587484.6A CN102569695B (en) | 2010-12-14 | 2010-12-14 | Preparation method for battery diaphragm |
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| Publication Number | Publication Date |
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| CN102569695A CN102569695A (en) | 2012-07-11 |
| CN102569695B true CN102569695B (en) | 2014-07-30 |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101222034A (en) * | 2008-01-04 | 2008-07-16 | 深圳市富易达电子科技有限公司 | High fused mass strength compound isolating film and preparation method and application thereof |
| CN101345296A (en) * | 2008-08-25 | 2009-01-14 | 陆英 | Preparation method and system for septum of lithium ion battery |
| CN101870164A (en) * | 2009-04-23 | 2010-10-27 | 富士胶片株式会社 | The drawing process of polymer film and the manufacture method of thin polymer film |
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- 2010-12-14 CN CN201010587484.6A patent/CN102569695B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101222034A (en) * | 2008-01-04 | 2008-07-16 | 深圳市富易达电子科技有限公司 | High fused mass strength compound isolating film and preparation method and application thereof |
| CN101345296A (en) * | 2008-08-25 | 2009-01-14 | 陆英 | Preparation method and system for septum of lithium ion battery |
| CN101870164A (en) * | 2009-04-23 | 2010-10-27 | 富士胶片株式会社 | The drawing process of polymer film and the manufacture method of thin polymer film |
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| CN102569695A (en) | 2012-07-11 |
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