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CN1758463A - Compound diaphragm used for lithium-ion secondary battery and lithium-ion secondary battery using the diaphragm - Google Patents

Compound diaphragm used for lithium-ion secondary battery and lithium-ion secondary battery using the diaphragm Download PDF

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Publication number
CN1758463A
CN1758463A CNA2004100811281A CN200410081128A CN1758463A CN 1758463 A CN1758463 A CN 1758463A CN A2004100811281 A CNA2004100811281 A CN A2004100811281A CN 200410081128 A CN200410081128 A CN 200410081128A CN 1758463 A CN1758463 A CN 1758463A
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barrier film
molecular weight
polyolefin
rechargeable battery
composite diaphragm
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CNA2004100811281A
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李鑫
肖久梅
曹东亮
李雪坎
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Xi'an Dinasi Science & Technology Co Ltd
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Xi'an Dinasi Science & Technology Co Ltd
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    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

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Abstract

This invention relates to a compound membrane used in a Li ionic second battery, which is composed of at least two layers of compound polyolefin micro-porous membranes, in which, at least one layer is a high intensity polyolefin micro-porous membrane A closing the temperature window, the other one is at least a layer of high temperature polythene micro-porous membrane B, A is manufactured by mixing the super high molecular weight polythene and the low melting point polyolefin and the B is made by irradiating and cross linking the polythene porous membrane, the compound membrane can be A/B structure, A/B/A or B/A/B structure.

Description

Be used for the composite diaphragm of lithium rechargeable battery and the lithium rechargeable battery of this barrier film of use
Technical field
The present invention relates to lithium rechargeable battery with barrier film and use the lithium rechargeable battery of this barrier film.
Technical background
Polyolefin micro porous polyolefin membrane is because normal temperature is difficult for being dissolved in organic solvent, and stable to electrolyte and electrode active material, so can be widely used in battery diaphragm, lithium rechargeable battery barrier film particularly.
As the Core Feature parts that lithium rechargeable battery is used, for guaranteeing the chemical property and the fail safe of battery, barrier film has following leading indicator, and wants every performance to take into account:
Tensile strength, high vertical (MD, draw direction) tensile strength are to satisfy plasticity_resistant deformation ability under the winding tension effect and the important requirement that keeps micropore stability in the battery manufacture process, and barrier film will have certain well-pressed degree to adapt to winding process in addition; High horizontal (TD, Width is perpendicular to the MD direction) tensile strength is to satisfy the important requirement that the barrier film antiknock is split or laterally torn; Usually the tensile strength of barrier film is pressed ASTM D882 standard testing.More than 50MPa, transverse tensile strength is more than 8MPa at least for the endwise tensile strength that generally requires barrier film.
Gas permeability, the resistance that the direct relation lithium ion moves in electrolyte and the internal resistance of cell are pressed ASTMD-726B standard testing Gurley value usually, and the air of test 10cc passes through 1 square inch of time that diaphragm area is used under 12.2 inch of water;
Hot turn-off performance, test barrier film micropore after fusion after the high-temperature heating is closed and hinder the ability of lithium ion migration, and the laboratory can be assessed the gas permeability (Gurley value) of diaphragm clip test barrier film be chilled to room temperature behind the certain hour that is heated between the thick smooth glass flat board of two 5mm in stove after;
Percent thermal shrinkage, test barrier film size in the vertical, horizontal shrinkage degree after high-temperature heating, the laboratory can be with the length L 1 and the width W 1 of the diaphragm clip of length L and width W test barrier film be chilled to room temperature behind the certain hour that is heated between the thick smooth glass flat board of two 5mm in stove after, with (L-L1)/L * 100%; (W-W1)/W * 100% is designated as the percent thermal shrinkage of barrier film in MD, TD direction.Owing to need to adopt 80 ℃ vacuum drying treatment in the battery production process, for this reason, the normal 90 ℃/60min of employing heat exposes, require the barrier film percent thermal shrinkage in MD, TD direction all less than 3%, or 105 ℃/15min heat exposes the back percent thermal shrinkage and all assesses less than 5% in MD, TD direction.
Effectively turn-off temperature window, refer in this temperature range, barrier film not only can turn-off in fusion, slows down or stops the migration of lithium ion, and can effectively prevent the positive and negative plate short circuit of battery, plays good iris action.
Had as method for preparing polyolefin micro-porous is known in the past, inorganic powders such as nano-calcium carbonate micro mist were blended in the high molecular polyolefine, and after the melting mixing moulding, extracted inorganic powder, and obtain the method for micro-porous film as CN1331496A.This method needs the extraction process of inorganic matter, and the microporous barrier that obtains is difficult to control the pore-forming uniformity owing to the reunion of inorganic powder in the mixing process becomes big.
Another typical process of making composite diaphragm is " dry method ", be called three layers of PP/PE/PP composite diaphragm of Celgard 2300 as the commodity of U.S. Celanese company, utilize the semi-crystalline character of PP, PE, after extrusion molding is shaped, the annealing crystallization processing, go out micro-crack (crazing) in crystalline region and amorphous area simple tension, then that trilamellar membrane is compound.The perforated membrane porosity of this manufactured is difficult to surpass 40%; Process conditions harshness in addition, the percent defective height, production cost is higher; Because molecular weight is difficult to stable extruding when too high, the polyolefinic weight average molecular weight of " dry method " process using for improving the tensile strength of film, can only be leaned on the high magnification stretch orientation generally below 300,000, the tearing toughness of this composite membrane is relatively poor, easily causes the inside battery micro-short circuit in the production.
Although the PP fusing point is up to 160-170 ℃, but because the PP porous layer has passed through the longitudinal stretching orientation process, vertical thermal contraction more than 20% still can take place under the high temperature more than 150 ℃, the available heat of three layers of PP/PE/PP composite diaphragm turn-offs window and still is confined to 135-150 ℃, and the fail safe of battery is still waited to improve.
In addition, use the manufacture method (" wet method ") of the high-intensity micro-porous film of ultra-high molecular weight polyethylene that a lot of motions has been arranged.For example, CN 1134491C, Japanese patent laid-open 8-34873,5-74442,5-335005, put down in writing the manufacture method of individual layer ultra-high molecular weight polyethylene micro-porous film in the 6-325747 communique, the polyethylene composition heating for dissolving that is about to contain ultra-high molecular weight polyethylene is at insoluble and cosolvent that mixing is good under the high temperature (paraffin oil of room temperature, solid paraffin, neck dioctyl phthalate etc.) in, with gluey plate of this hot solution cooling forming gelation or film, the above-mentioned jelly that freezes is heated the after-drawing attenuate, strengthen, extract solvent, oven dry and obtain the method for micro-porous film.These methods are referred to as thermally induced phase separation in the macromolecule textbook, by control solidification forming or solid, liquid phase-splitting thermokinetics condition, can obtain nanometer micropore (width in hole is in the 5-100 nanometer) polyolefin micro porous polyolefin membrane, feature is that pore-size distribution is narrow, even and the aperture is little, owing to adopt extrahigh-molecular weight polyolefins and, can obtain higher intensity and tear-proof, anti-acupuncture performance through the hot-stretch orientation; It is that base material is made micro-porous film and can be obtained taking into account between high porosity and high strength, the manufacturability that thermally induced phase separation adopts HMW (weight average molecular weight is more than 200,000) polyolefin, help to improve the chemical property of battery, so can be used for battery diaphragm.Although the barrier film of this manufactured can turn-off at 135-150 ℃ high temperature, but battery because of fortuitous event as overcharge, when thermal runaway takes place in inner micro-short circuit, the inner high temperature that still can reach more than 150 ℃, this moment, the barrier film percent thermal shrinkage was bigger than normal, can cause short circuit between the inside battery positive and negative plate, battery is blasted.Therefore the little porous septum of above-mentioned individual layer high molecular polyolefine is waiting raising aspect the lithium rechargeable battery fail safe.The fusing point of above-mentioned ultra-high molecular weight polyethylene is generally at 135 ℃ in addition, and therefore the initial shutoff temperature of little porous septum also is limited in more than 135 ℃.
The heat-resisting micro-porous film of para-aramid, polyimides or polyamidoimide that the employing phase inversion method that the document of the high temperature resistant barrier film of compound little porous has CN 1331496A to propose is made, although above-mentioned material has good high-temperature intensity during as dense material, but manufacture very serious that room temperature strength reduces behind the porous material, fragility is big, easily tears; During the another one shortcoming, phase inversion method is made perforated membrane and is easily formed dense layer surface, and technique controlling difficulty is big, is difficult to complete being combined with each other with the polyalkene diaphragm that can turn-off, and manufacturability is relatively poor.
The employing non-weaving cloth method that other documents of making high temperature resistant barrier film have CN 1179855A to propose, weak point is cut inorfil or the fire resistant organic fibre hot-rolling is pressed into porous septum, the aperture size that this method obtains is at micron order, and be difficult to the homogenizing pore-forming, unfavorable to the growth of battery performance and anti-dendrite.
To the composite characteristic requirement of lithium rechargeable battery, the requirement of the productivity ratio of stability test, battery security, battery constantly improves recently.In order to improve battery behavior, require barrier film to have suitable nanoscale aperture and porosity and permeability, when the aperture became big significantly, the growth of dendrite just became easily, and the fusion turn-off capacity descends, and has the danger that damages battery security.In addition, in compression, acupuncture, 150 ℃ of destructive testings such as hot case, even battery deforms, local contraction appears in barrier film, does not also make the physics contact takes place between the electrode plates, and this is very important keeping in the fail safe.Studies show that in addition barrier film has lower shutoff initial temperature the fail safe that guarantees battery is had great value, can in time weaken, end the carrying out of exothermic reaction in the battery, prevent the generation of thermal runaway in the battery, especially to the protection of fortuitous events such as overcharging.Be limited to existing single-layer septum and be difficult to all satisfy above-mentioned all harsh performance requirements, therefore wish to develop to take into account above-mentioned every performance, especially the composite diaphragm that has wide available heat shutoff window: not only have wide heat and turn-off temperature range (115-200 ℃), and between whole high-temperature region, have the composite diaphragm that low percent thermal shrinkage (MD, TD direction are all less than 5%) can prevent the short circuit of positive and negative plate physics.
The object of the present invention is to provide and have good window and low percent thermal shrinkage, the high hot strength of effectively turn-offing, and having high porosity and gas permeability, fine nanoscale hole shape to be fit to the little porous composite diaphragm of polyolefin that lithium rechargeable battery is used, it can improve battery behavior, battery security.
Summary of the invention
The present inventor has carried out deep research for solving above-mentioned problem, find to adopt ethylene-alpha-olefin copolymer or polyphosphazene polymer isobutene in low melting point polyolefin such as the fusing point 95-125 ℃ scope to make little porous septum separately, intensity can not satisfy continuous production requirement, and the barrier film deflection is relatively poor.Adopt separately ultrahigh molecular weight polyethylene to make micro-porous film, initial shutoff temperature is not ideal enough, and the high strength micro-porous film that therefore adopts the two composite material to make wide shutoff temperature window then is feasible.
And adopt the limitation that just can avoid the problems referred to above and single-layer septum without the little high temperature resistant barrier film of porous polymer weight northylen cross-linking radiation of stretch orientation and the compound use of polyalkene diaphragm of the wide shutoff window of drawn orientation enhancing, reach above-mentioned expectation target, thereby obtain having the lithium rechargeable battery of higher-security and other combination properties.
The little porous septum A of the high-strength polyolefin of wide shutoff temperature window adopts the hot-stretch orientation to strengthen to make, adopt the three-phase blended compound material of ultra-high molecular weight polyethylene and low melting point polyolefin and cosolvent, three's percentage by weight is respectively ultra-high molecular weight polyethylene: 2-20%, low melting point polyolefin: 8-30%, cosolvent: 90-50%.Be mixed with and by measuring pump slip imported parallel parallel dual-screw extruding machine behind the unit for uniform suspension and carry out melting mixing, kneading becomes even glue under 140-240 ℃ of high temperature, the smelt gear pump supercharging is after die head is extruded curtain coating on chill roll, cooling remains film forming with the state that the nanoscale under the high temperature mixes fast, obtains frozen glue shape article shaped master slice A1; Then to master slice A1 carry out 90-110 ℃ of hot-stretch, hot-stretch multiplying power be 4-8 doubly, can adopt unidirectional or two-way hot-stretch; Carry out 90-110 ℃ thermal finalization subsequently and handle 10-600S, the control shrinkage is at 5-20%; Extraction is fallen operations such as cosolvent, oven dry and is handled; The weight average molecular weight of making the ultra-high molecular weight polyethylene of barrier film A is 100-1000 ten thousand, low melting point polyolefin is ethylene-alpha-olefin copolymer or the polyphosphazene polymer isobutene in the fusing point 95-125 ℃ scope, and cosolvent is paraffin oil, neck dioctyl phthalate, neck phthalic acid two isodecyl esters, aviation kerosine etc.; Three's percentage by weight is respectively ultra-high molecular weight polyethylene: 2-20%, low melting point polyolefin: 8-25%, cosolvent: 90-55%.It is the ethylene-alpha-olefin copolymers such as metallocene low density polyethylene (LDPE) Exceed 1018 that 114 ℃ metallocene low density polyethylene (LDPE) Exceed3518 or fusing point are 118 ℃ that low melting point polyolefin can adopt fusing point.
The THICKNESS CONTROL of the little porous septum A of the high-strength polyolefin of wide shutoff temperature window is the 8-35 micron, porosity is 35-70Vol.%, room temperature tensile strength MD direction is 70-150MPa, the TD direction is more than 8MPa, 90 ℃/60min heat expose percent thermal shrinkage in MD, TD direction all less than 3%, Gurley value under the single-layer septum A room temperature is 15-40S/10CC, effective shutoff temperature window of the little porous septum of high-strength polyolefin is 115-200 ℃, exposes the back gas permeability in this temperature range heat and is reduced to the Gurley value greater than 200S/10CC.
The High molecular weight polyethylene of weight average molecular weight 500,000-1,000 ten thousand is made micro-porous film as base material, even drawn intensive treatment not during up to 40-85Vol.%, also can obtain the above room temperature tensile strength of 8MPa in porosity.Use ultra high molecular weight polyethylene (weight average molecular weight 50-1000 ten thousand) or its composition 15-40 part, the ultra-high molecular weight polyethylene of weight average molecular weight 1,000,000-2,500,000 preferably, at first with flash-point at cosolvent more than 180 ℃, as dioctyl phthalate, diisooctyl phthalate, diisononyl phthalate, aviation kerosine, decahydronaphthalene, paraffin wax wet goods 85-60 part is carried out mixed processing, be mixed with and by measuring pump slip imported parallel parallel dual-screw extruding machine behind the unit for uniform suspension and carry out melting mixing, kneading becomes even glue under 140-240 ℃ of high temperature, the smelt gear pump supercharging is after die head is extruded curtain coating on 15-50 ℃ chill roll, utilizing fast, cooling remains film forming with the thermodynamic state that the nanoscale under the high temperature mixes, obtain frozen glue shape article shaped B1, through further extracting solvent, oven dry obtains micro-porous film master slice B2 after handling.Adopt cross-linking radiation technology that microporous polyethylene film B2 is handled and be easy to improve its elevated temperature strength, it is 30-200KGy that cross-linking radiation is handled the irradiation dose that adopts, and obtains the little porous septum B of refractory polyethylene.Also directly radiation treatment B1 is after solvent is fallen in further extraction, and oven dry obtains micro-porous film B after handling.Adopt the ratio of the cross-linking products (gel) of 140 ℃/24h of dimethylbenzene reflux extraction method test crosslinked back generation, it is not enough to cross under the low irradiation dose polyethylene barrier film degree of cross linking, for reaching certain resistance to elevated temperatures, the gel content of the little porous septum A of polyethylene should be greater than 30%; Irradiation-induced degradation easily takes place in the polyethylene barrier film under the too high irradiation dose, and intensity weakens on the contrary.Cross-linking radiation can adopt gamma-rays or electron beam irradiation to handle, and is good with the latter.
The THICKNESS CONTROL of the little porous septum B of refractory polyethylene is in the 8-25 micrometer range, thickness is less than bad control on 8 microns the thin-film technique, with turn-off the compound back heat resistanceheat resistant of film contractility deficiency, thickness greater than 25 microns barrier film with turn-off the compound back of film and influence the gas permeability of composite diaphragm; Porosity is 40-85Vol.%, room temperature tensile strength MD, TD direction are 8-40MPa, handle by cross-linking radiation, barrier film B 90-200 ℃/15min heat expose the back percent thermal shrinkage in MD, TD direction all less than 5%, the Gurley value of single-layer septum B is 5-25S/10CC (ASTM D-726B).Handle through cross-linking radiation, the little porous septum B of the refractory polyethylene of individual layer substantially still loses the fusion turn-off capacity in 135-250 ℃ of scope, and micropore is difficult to closed, therefore also need cooperate to adopt above-mentioned high strength can turn-off the little porous septum A of polyolefin.
The High molecular weight polyethylene of weight average molecular weight 500,000-1,000 ten thousand is made micro-porous film as base material, drawn intensive treatment not, in porosity during up to 40-85Vol.%, be difficult to obtain the above room temperature tensile strength of 60MPa,, be to be not enough to be used for separately lithium ion battery separator aspect intensity generally at 8-40MPa; Though the stretching intensive treatment has improved the room temperature tensile strength of the little porous of High molecular weight polyethylene greatly, the film of handling is bigger in elevated temperature heat shrinkage more than 135 ℃ like this, and it is not enough to be applied to the lithium rechargeable battery fail safe separately; The polyethylene barrier film of cross-linking radiation is because C-C key crosslinked even more than the fusing point that is heated to before being untreated, still has very high elevated temperature strength, and can melt-flow, loses hot turn-off capacity substantially; Even carry out cross-linking radiation for the little porous septum of the High molecular weight polyethylene after the stretching intensive treatment, the high temperature turn-off capacity not only can reduce greatly, and percent thermal shrinkage is also bigger than normal.For solving above-mentioned limitation and deficiency, adopt without the little high temperature resistant barrier film of porous polymer weight northylen cross-linking radiation of stretch orientation and the compound use of turn-offed polyalkene diaphragm of drawn orientation enhancing and just can avoid the problems referred to above and limitation.For enlarging the effective shutoff temperature range that to turn-off polyalkene diaphragm, especially low temperature turn-off capacity, adopt the blended compound material of low melting point polyolefin and ultra-high molecular weight polyethylene, wherein fusing point is the intensity that 135 ℃ ultra-high molecular weight polyethylene can improve composite material, ethylene-alpha-olefin copolymer in the fusing point 95-125 ℃ scope or polyphosphazene polymer isobutene can reduce barrier film as the main body of composite material initial shutoff temperature.
Utilize free radical remaining behind the barrier film B cross-linking radiation that barrier film A and the roll-in of barrier film B direct heat are combined with each other, it is to carry out cross-linking radiation at barrier film B to handle in back 48 hours and carry out immediately that hot-rolling is pressed, and compound with roll-in in 8 hours is good.It is 50-100 ℃ that hot-rolling is pressed the preheat temperature to barrier film, and the roll-in line pressure is 1-50kgf/cm, and composite diaphragm both can be the A/B double-layer structure, also can be three layers of A/B/A or B/A/B three-decker.With the A/B double-layer structure is example, and barrier film A, B thickness were by design in 1: 1, and the composite diaphragm gross thickness is controlled in the 16-50 micrometer range, is good with the 25-35 micron thickness; The Gurley value is 20-50S/10CC (ASTM D-726B), the hot exposed composite barrier film of 90-200 ℃/15min percent thermal shrinkage in MD, TD direction all less than 5%.
Adopt the composite diaphragm of the wide shutoff window of above-mentioned principle manufacturing to be particularly suitable for the liquid lithium ion secondary cell, especially high-capacity battery, improve greatly with anode pole piece, cathode pole piece and the security reliability that is adsorbed in organic electrolyte and the closed container in the above-mentioned barrier film and draws the lithium rechargeable battery that anode and cathode terminals manufactures
Embodiment:
1, the little porous septum A of the high-strength polyolefin of wide shutoff window
Material prescription: the polyethylene (UHMWPE) of the super high molecular weight of weight average molecular weight (Mw) 150-200 ten thousand: 5 parts; Fusing point is metallocene low density polyethylene (LDPE) Exceed 3518:20 part of 114 ℃, 75 parts of diisooctyl phthalates (DIDP);
Processing method:
At first carry out dispersing and mixing and handled 1-4 hour, be mixed with unit for uniform suspension; ( 50,1: 48) carry out melting mixing, the twin-screw temperature is set to 140,160 by measuring pump slip to be imported parallel parallel dual-screw extruding machine then, 180,220,220,220,220,220 ℃, the smelt gear pump temperature is set to 220 ℃, and the hanger-style die temperature is set to 200 ℃; Adopt two chill rolls of  400, roll temperature is controlled at 25-30 ℃, and film forming thickness is controlled to be the 60-70 micron; Then it is carried out 80,90,100 ℃ sorting cylinder preheating, the stretch section temperature is controlled in 95-105 ℃ the DIDP oil bath carries out, and the hot-stretch multiplying power is 6 times, and rate of extension is 80m/min, adopts unidirectional heat to stretch; And then carry out 95-100 ℃ of thermal finalization and handle 20-30S, the control percent thermal shrinkage is at 6-15%; Adopt decane to divide the extraction of three steps to fall solvent DIDP then, obtain micro-porous film A after 40 ℃ of oven dry are handled;
Micro-porous film A thickness is the 15-20 micron; Porosity is 45-55Vol.%; Room temperature tensile strength MD direction is 90-110MPa, and the TD direction is 6-12MPa; 90 ℃/60min heat expose percent thermal shrinkage in MD, TD direction all less than 3%; Gurley value under the single-layer septum A room temperature is 20-25S/10CC; 115 ℃/15min heat exposes the back gas permeability and is reduced to the Gurley value greater than 240S/10CC.
2, the little porous septum B of high temperature polyethylene
Material prescription: 25 parts of the polyethylene (UHMWPE) of the super high molecular weight of weight average molecular weight (Mw) 150-200 ten thousand; 75 parts of diisooctyl phthalates (DIDP);
Processing method:
At first carried out mixed processing 1-4 hour, and be mixed with unit for uniform suspension; ( 50,1: 48) carry out melting mixing, the twin-screw temperature is set to 140,160 by measuring pump slip to be imported parallel parallel dual-screw extruding machine then, 180,220,220,220,220,200 ℃, the smelt gear pump temperature is set to 200 ℃, and the hanger-style die temperature is set to 200 ℃; Adopt two chill rolls of  400, roll temperature is controlled at 25-30 ℃, casting film-forming B1, and THICKNESS CONTROL is 15 microns; Adopt decane to divide the extraction of three steps to fall solvent DIDP then, obtain micro-porous film B2 after 50 ℃ of oven dry are handled; Adopt electron beam to carry out cross-linking radiation and handle, irradiation dose is 70-120KGy, and gel content is 40-70%.Obtain the little porous septum B of refractory polyethylene.
The thickness of porous septum B is the 12-15 micron, porosity is 60-70Vol.%, room temperature tensile strength MD, TD direction are 15-20MPa, all less than 5%, the Gurley value of single-layer septum A is 15-22S/10CC (ASTM D-726B) to 90-200 ℃/15min heat exposure percent thermal shrinkage in MD, TD direction.
3, composite diaphragm
It is to carry out cross-linking radiation at barrier film B to handle in back 8 hours and carry out immediately that hot-rolling is pressed, and it is 80-90 ℃ that hot-rolling is pressed the preheat temperature to barrier film A/B, and the roll-in line pressure is 5-10kgf/cm, and composite diaphragm is the A/B double-layer structure; The compound back of barrier film A, B gross thickness is the 25-30 micron; The Gurley value is 25-35S/10CC; The hot exposed composite barrier film of 90-200 ℃/15min percent thermal shrinkage in MD, TD direction all less than 5%; 115-220 ℃/15min heat exposes the back gas permeability and is reduced to the Gurley value greater than 240S/10CC.

Claims (9)

1, a kind of composite diaphragm that is used for lithium rechargeable battery, it is characterized in that this barrier film has the little porous septum of two-layer at least polyolefin to be composited, wherein one deck is the little porous septum A of high-strength polyolefin of wide shutoff temperature window at least, and one deck is the little porous septum B of refractory polyethylene at least in addition.
2, the composite diaphragm that is used for lithium rechargeable battery according to claim 1, the thickness that it is characterized in that the little porous septum A of high-strength polyolefin of wide shutoff temperature window is the 8-35 micron, porosity is 35-70Vol.%, room temperature tensile strength MD direction is 70-150MPa, the TD direction is more than 8MPa, 90 ℃/60min heat exposes percent thermal shrinkage at MD, the TD direction is all less than 3%, Gurley value under the single-layer septum A room temperature is 15-40S/10CC, effective shutoff temperature window of the little porous septum of high-strength polyolefin is 115-200 ℃, exposes the back gas permeability in this temperature range heat and is reduced to the Gurley value greater than 200S/10CC.
3, the composite diaphragm that is used for lithium rechargeable battery according to claim 1, the little porous septum A of high-strength polyolefin that it is characterized in that wide shutoff temperature window makes like this, at first utilizes thermally induced phase separation to make the three-phase blended compound material master slice A1 of ultra-high molecular weight polyethylene and low melting point polyolefin and cosolvent; Then to master slice A1 carry out 90-110 ℃ of hot-stretch, hot-stretch multiplying power be 4-8 doubly, can adopt unidirectional or two-way hot-stretch; 10-600S is handled in 90-110 ℃ of thermal finalization; Operations such as extraction, oven dry are handled; The weight average molecular weight of making the ultra-high molecular weight polyethylene of barrier film A is 100-1000 ten thousand, low melting point polyolefin is ethylene-alpha-olefin copolymer or the polyphosphazene polymer isobutene in the fusing point 95-125 ℃ scope, and cosolvent is paraffin oil, neck dioctyl phthalate, neck phthalic acid two isodecyl esters, aviation kerosine; Three's percentage by weight is respectively ultra-high molecular weight polyethylene: 2-20%, low melting point polyolefin: 8-30%, cosolvent: 90-50%.
4, low melting point polyolefin according to claim 3, it is characterized in that adopting fusing point is the metallocene low density polyethylene (LDPE) Exceed1018 that 114 ℃ metallocene low density polyethylene (LDPE) Exceed 3518 or fusing point are 118 ℃.
5, the composite diaphragm that is used for lithium rechargeable battery according to claim 1, the gel content that it is characterized in that the little porous septum B of refractory polyethylene is greater than 30%, high temperature resistant barrier film is to make like this, at first utilize thermally induced phase separation to make the little porous septum master slice of High molecular weight polyethylene, then master slice being carried out cross-linking radiation handles, irradiation dose is 30-200KGy, and the weight average molecular weight of making the High molecular weight polyethylene of barrier film B is 50-1000 ten thousand.
6, the composite diaphragm that is used for lithium rechargeable battery according to claim 1, the thickness that it is characterized in that the little porous septum B of refractory polyethylene is the 8-25 micron, porosity is 40-85Vol.%, room temperature tensile strength MD, TD direction are 8-40MPa, all less than 5%, the Gurley value of single-layer septum B is 5-25S/10CC to 90-200 ℃/15min heat exposure percent thermal shrinkage in MD, TD direction.
7, the composite diaphragm that is used for lithium rechargeable battery according to claim 1, it is characterized in that the compound of barrier film is to utilize barrier film B remnants' free radical that barrier film A and the roll-in of barrier film B direct heat are combined with each other, it is to carry out cross-linking radiation at barrier film B to handle in back 48 hours and carry out immediately that hot-rolling is pressed, it is 50-100 ℃ that hot-rolling is pressed the preheat temperature to barrier film, the roll-in line pressure is 1-50kgf/cm, composite diaphragm both can be the A/B double-layer structure, also can be three layers of A/B/A or B/A/B three-decker.
8, the composite diaphragm that is used for lithium rechargeable battery according to claim 1 is characterized in that the composite diaphragm gross thickness is the 16-50 micron, and the Gurley value is 15-50S/10CC.
9, a kind of lithium rechargeable battery that uses this barrier film, it is characterized in that using the described composite diaphragm that is used for lithium rechargeable battery of claim 1, also contain anode pole piece, cathode pole piece and be adsorbed in organic electrolyte and the outside closed container in the above-mentioned barrier film and draw anode and cathode terminals.
CNA2004100811281A 2004-10-10 2004-10-10 Compound diaphragm used for lithium-ion secondary battery and lithium-ion secondary battery using the diaphragm Pending CN1758463A (en)

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CN101861667A (en) * 2007-11-19 2010-10-13 株式会社Lg化学 Separator having porous coating layer and electrochemical device comprising the same
CN101150182B (en) * 2006-09-18 2011-12-07 深圳市比克电池有限公司 Lithium ion battery electrode slice, electric core and its making method
CN101740744B (en) * 2008-11-19 2013-03-20 Tdk株式会社 Lithium-ion secondary battery separator and lithium-ion secondary battery
WO2013091297A1 (en) * 2011-12-22 2013-06-27 天津东皋膜技术有限公司 Microporous membrane of polyethylene-based composite material with adhesion under hot pressing
CN103187549A (en) * 2011-12-28 2013-07-03 山东东岳高分子材料有限公司 Diaphragm for lithium ion battery and preparation method thereof
CN103219483A (en) * 2013-04-27 2013-07-24 中材科技股份有限公司 Composite lithium battery diaphragm and preparation method thereof
CN103354279A (en) * 2013-06-20 2013-10-16 深圳中兴创新材料技术有限公司 Three-layer membrane for lithium ion battery
CN101997102B (en) * 2009-08-26 2013-11-06 比亚迪股份有限公司 Lithium ion battery diaphragm and manufacturing method thereof
CN104201312A (en) * 2014-08-19 2014-12-10 中国科学院化学研究所 Polyethylene membrane applied to high-power lithium ion battery and preparation method of polyethylene membrane applied to high-power lithium ion battery
CN104425790A (en) * 2013-08-21 2015-03-18 通用汽车环球科技运作有限责任公司 Cross-linked multilayer porous polymer membrane battery separators
CN105958111A (en) * 2016-06-14 2016-09-21 东莞市创明电池技术有限公司 Electrolyte for lithium ion battery and lithium ion battery
JP2017165938A (en) * 2016-03-11 2017-09-21 東ソー株式会社 Separator made of ultra high molecular weight polyethylene composition
US10038182B2 (en) 2011-05-12 2018-07-31 Ningbo Institute Of Material Technology And Engineering, Chinese Academy Of Sciences Graphene coating modified electrode plate for lithium secondary battery and method for producing the same
CN111108627A (en) * 2018-08-17 2020-05-05 株式会社Lg化学 Crosslinked polyolefin separator and method for producing same
WO2020192678A1 (en) * 2019-03-25 2020-10-01 Ford Cheer International Limited Metal-organic-framework (mof) coated composite separators for electrochemical devices and applications of same
CN115954612A (en) * 2023-03-15 2023-04-11 河南新太行电源股份有限公司 High-temperature-resistant safety lithium ion battery diaphragm and preparation method thereof
US11715864B2 (en) 2017-02-07 2023-08-01 Ford Cheer International Limited Metal-organic-framework (MOF) coated composite separators for electrochemical devices and applications of same
CN116897107A (en) * 2020-12-15 2023-10-17 赛尔格有限责任公司 Dry-laid polyethylene films, coated films, separators and related methods

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* Cited by examiner, † Cited by third party
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CN101150182B (en) * 2006-09-18 2011-12-07 深圳市比克电池有限公司 Lithium ion battery electrode slice, electric core and its making method
CN101861667B (en) * 2007-11-19 2013-10-16 株式会社Lg化学 Separator with porous coating and electrochemical device containing same
CN101861667A (en) * 2007-11-19 2010-10-13 株式会社Lg化学 Separator having porous coating layer and electrochemical device comprising the same
CN101740744B (en) * 2008-11-19 2013-03-20 Tdk株式会社 Lithium-ion secondary battery separator and lithium-ion secondary battery
CN101997102B (en) * 2009-08-26 2013-11-06 比亚迪股份有限公司 Lithium ion battery diaphragm and manufacturing method thereof
US10038182B2 (en) 2011-05-12 2018-07-31 Ningbo Institute Of Material Technology And Engineering, Chinese Academy Of Sciences Graphene coating modified electrode plate for lithium secondary battery and method for producing the same
WO2013091297A1 (en) * 2011-12-22 2013-06-27 天津东皋膜技术有限公司 Microporous membrane of polyethylene-based composite material with adhesion under hot pressing
CN103187549B (en) * 2011-12-28 2015-04-22 山东东岳高分子材料有限公司 Diaphragm for lithium ion battery and preparation method thereof
CN103187549A (en) * 2011-12-28 2013-07-03 山东东岳高分子材料有限公司 Diaphragm for lithium ion battery and preparation method thereof
CN103219483A (en) * 2013-04-27 2013-07-24 中材科技股份有限公司 Composite lithium battery diaphragm and preparation method thereof
CN103354279A (en) * 2013-06-20 2013-10-16 深圳中兴创新材料技术有限公司 Three-layer membrane for lithium ion battery
CN104425790A (en) * 2013-08-21 2015-03-18 通用汽车环球科技运作有限责任公司 Cross-linked multilayer porous polymer membrane battery separators
CN104201312A (en) * 2014-08-19 2014-12-10 中国科学院化学研究所 Polyethylene membrane applied to high-power lithium ion battery and preparation method of polyethylene membrane applied to high-power lithium ion battery
JP2017165938A (en) * 2016-03-11 2017-09-21 東ソー株式会社 Separator made of ultra high molecular weight polyethylene composition
CN105958111A (en) * 2016-06-14 2016-09-21 东莞市创明电池技术有限公司 Electrolyte for lithium ion battery and lithium ion battery
US11715864B2 (en) 2017-02-07 2023-08-01 Ford Cheer International Limited Metal-organic-framework (MOF) coated composite separators for electrochemical devices and applications of same
CN111108627A (en) * 2018-08-17 2020-05-05 株式会社Lg化学 Crosslinked polyolefin separator and method for producing same
WO2020192678A1 (en) * 2019-03-25 2020-10-01 Ford Cheer International Limited Metal-organic-framework (mof) coated composite separators for electrochemical devices and applications of same
CN116897107A (en) * 2020-12-15 2023-10-17 赛尔格有限责任公司 Dry-laid polyethylene films, coated films, separators and related methods
EP4251422A4 (en) * 2020-12-15 2024-10-30 Celgard, LLC POLYETHYLENE MEMBRANES FOR DRY PROCESSES, COATED MEMBRANES, SEPARATORS AND RELATED PROCESSES
CN115954612A (en) * 2023-03-15 2023-04-11 河南新太行电源股份有限公司 High-temperature-resistant safety lithium ion battery diaphragm and preparation method thereof

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