CN103972449B - Heat-resistant porous isolating membrane and production method thereof - Google Patents
Heat-resistant porous isolating membrane and production method thereof Download PDFInfo
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- CN103972449B CN103972449B CN201410108758.7A CN201410108758A CN103972449B CN 103972449 B CN103972449 B CN 103972449B CN 201410108758 A CN201410108758 A CN 201410108758A CN 103972449 B CN103972449 B CN 103972449B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
- C08J9/36—After-treatment
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/403—Manufacturing processes of separators, membranes or diaphragms
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/411—Organic material
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
- C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
- C08J2323/10—Homopolymers or copolymers of propene
- C08J2323/12—Polypropene
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2433/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
- C08J2433/24—Homopolymers or copolymers of amides or imides
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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
Abstract
The invention provides a heat-resistant porous isolating membrane and a production method thereof. The heat-resisting porous isolating membrane comprises a base material and a heat-resistant resin layer, wherein the base material has a porous structure; and the heat-resistant resin layer is arranged on a surface of the base material and comprises a polyvinyl acetamidehomopolymer or a copolymer formed by polyvinyl acetamide and sodium acrylate. Compared with the prior art, the surface of the porous base material is coated with the heat-resistant resin layer formed by the polyvinyl acetamidehomopolymer or the copolymer formed by polyvinyl acetamide and sodium acrylate, so that the heat-resistant porous isolating membrane comprising the heat-resistant resin layer is produced. Therefore, the provided heat-resistant porous isolating membrane can effectively reduce electrode short-circuit and insufficient battery safety caused by thermal contraction of the isolating membrane as well as battery performance reduction caused by over-low imbibition ratio of the isolating membrane.
Description
Technical field
The present invention is about a kind of heat-resisting porous isolating membrane, and in particular to a kind of heat-resisting porous isolating membrane for lithium ion battery and manufacture method thereof.
Background technology
Isolating membrane is a kind of macromolecule membrane, is applied to lithium ion battery, and it produces short circuit to prevent from producing brought into physical contact between positive and negative electrode material between positive pole and negative pole.Meanwhile, the microporous properties of isolating membrane allows the free ion in electrolyte therebetween to pass through, and makes battery produce voltage.But, when the thermostability of isolating membrane is the best, the dimensional contraction rate of isolating membrane can be caused to improve, thus result in positive and negative pole material directly contact the short-circuit probability caused also thus promote.Furthermore, isolating membrane is mostly by obtained by the non-polar materials such as polyolefin, and the solvent used in electrolyte is polar solvent.Consequently, it is possible to isolating membrane is the lowest for the imbibition ratio of electrolyte, ionic conductance is made to decline and cause the usefulness of battery to reduce.Therefore, how to improve the thermostability of isolating membrane and make it have good imbibition ratio to be considerable for electrolyte.
Currently in order to improve the thermostability of isolating membrane, general preparation method is in the refractory coating of isolating membrane surface applying implenent inorganic particulate, inorganic particulate for example, aluminium oxide, titanium dioxide or silicon dioxide etc..But the method very likely causes coming off of inorganic particulate because inorganic particulate is the best with the tack of isolating membrane, and cause the shortcoming such as the hydraulic performance decline of isolating membrane or the safety deficiency of battery.
Summary of the invention
Because the problems referred to above, the present invention proposes a kind of heat-resisting porous isolating membrane, it has the dimensional stability of excellence, has good imbibition ratio to electrolyte and preferably pierce through intensity, can avoid being previously mentioned the problems such as inorganic particulate comes off during porous isolating membrane uses in prior art simultaneously.
The heat-resisting porous isolating membrane that the present invention provides comprises base material, and this base material has loose structure；First heat-resistant resin layer, it is arranged at the first surface of above-mentioned base material, and this heat-resistant resin layer is by PVAA homopolymer, or the copolymer formed by PVAA and sodium acrylate is formed.
According to one embodiment of the invention, base material is the loose structure base material of the single or multiple lift containing polyolefin, polyester or polyamide.
According to still another embodiment of the invention, the weight average molecular weight scope of the heat stable resin forming heat-resistant resin layer is between 20 ten thousand to 150 ten thousand.
According to another embodiment of the present invention, the imbibition ratio of heat-resisting porous isolating membrane is more than 3.0, and the percent thermal shrinkage of heat-resisting porous isolating membrane bearing of trend is less than or equal to 5%.
According to another embodiment of the present invention, the air penetrability (Gurley) of heat-resisting porous isolating membrane is 12 to 30 (sec/10cc).
According to still another embodiment of the invention, above-mentioned heat-resisting porous isolating membrane also includes the second heat-resistant resin layer, it is arranged at above-mentioned base material second surface, wherein, second surface is relative with first surface, above-mentioned second heat-resistant resin layer is by PVAA homopolymer, or the copolymer formed by PVAA and sodium acrylate is formed.
The present invention also proposes the manufacture method of a kind of heat-resisting porous isolating membrane, the heat-resisting porous isolating membrane utilizing the method to prepare has the dimensional stability of excellence, has good imbibition to electrolyte and the most preferably pierce through intensity, can avoid the problems such as the particle being previously mentioned in prior art comes off simultaneously.
The manufacture method of above-mentioned heat-resisting porous isolating membrane comprises: providing base material, this base material has loose structure；The heat stable resin solution that solid content is 1% to 7% is coated this base material first surface to form the first heat-resistant resin layer, wherein, the heat stable resin forming this heat stable resin solution is PVAA homopolymer, or is the copolymer of PVAA and sodium acrylate formation；The base material that this has the first heat-resistant resin layer is dried to prepare heat-resisting porous isolating membrane.
According to one embodiment of the invention, base material is the loose structure base material of the single or multiple lift containing polyolefin, polyester or polyamide.
According to still another embodiment of the invention, the weight average molecular weight scope of heat stable resin is between 20 ten thousand to 150 ten thousand.
According to still another embodiment of the invention, the solvent used in heat stable resin solution is water, ethanol, ethylene glycol, isopropanol or a combination thereof.
According to still another embodiment of the invention, above-mentioned manufacture method the imbibition ratio of the heat-resisting porous isolating membrane prepared is more than 3.0, and the percent thermal shrinkage of heat-resisting porous isolating membrane bearing of trend is less than or equal to 5%.
According to another embodiment of the present invention, above-mentioned manufacture method the air penetrability (Gurley) of the heat-resisting porous isolating membrane prepared is 12 to 30 (sec/10ml).
According to another embodiment of the present invention, above-mentioned manufacture method also includes: the heat stable resin solution that solid content is 1% to 7% is coated base material second surface to form the second heat-resistant resin layer, wherein, second surface is relative with first surface, the heat stable resin forming this second heat-resistant resin layer is PVAA homopolymer, or is the copolymer of PVAA and sodium acrylate formation；It is dried this base material with the second heat-resistant resin layer to prepare heat-resisting porous isolating membrane.
Compared with prior art, the copolymer formation heat-resistant resin layer that the present invention is formed with sodium acrylate by porous substrate surface painting polyethylene yl acetamide homopolymer or PVAA, and then prepare the heat-resisting porous isolating membrane containing above-mentioned heat-resistant resin layer.And the heat-resisting porous isolating membrane that the present invention provides at adhesive force, imbibition ratio, percent thermal shrinkage, pierce through in the performance test of the isolating membrane characteristic such as intensity and air penetrability, properties is superior to commercially available isolating membrane, therefore, can effectively reduce the electric pole short circuit caused due to isolating membrane thermal contraction, and the battery performance caused because its imbibition ratio is too low declines.In addition, owing to having good adhesive force between heat-resistant resin layer and the base material of the present invention, avoid in prior art and cause coming off of inorganic particulate because inorganic particulate is the best with the tack of isolating membrane, and cause the hydraulic performance decline of isolating membrane or the shortcoming that battery security is not enough.
Accompanying drawing explanation
Nothing.
Detailed description of the invention
In order to above and other objects of the present invention, feature and advantage can be become apparent, preferred embodiment cited below particularly, it is described in detail below:
Heat-resisting porous isolating membrane provided by the present invention, it comprises base material and the first heat-resistant resin layer, and wherein, this base material has loose structure；First heat-resistant resin layer is arranged at the first surface of above-mentioned base material, and this first heat-resistant resin layer is by PVAA homopolymer, or the copolymer formed by PVAA and sodium acrylate is formed.
In above-mentioned heat-resisting porous isolating membrane, base material can be the loose structure base material of the single or multiple lift containing polyolefin, polyester or polyamide.
In above-mentioned heat-resisting porous isolating membrane, the weight average molecular weight scope of heat stable resin is 20 ten thousand to 150 ten thousand, preferably 70 ten thousand to 80 ten thousand.When the weight average molecular weight of heat stable resin is the biggest, the processability of its coating can be affected；When the weight average molecular weight of heat stable resin is the least, the heat-resisting effect that can cause its first heat-resistant resin layer formed is the best, and then affects the heat shrinkability characteristic of heat-resisting porous isolating membrane.
In above-mentioned heat-resisting porous isolating membrane, heat-resisting porous isolating membrane is for the imbibition ratio (ability of imbibition ratio reflection barrier film Electolyte-absorptive of electrolyte, being the index weighing barrier film with compatibility of electrolyte, imbibition ratio=(W2-W1)/W1, W1 are the weight after dry type isolating membrane is weighed；W2 is that dry type isolating membrane soaks in the electrolytic solution, until absorption equilibrium, further takes out wet barrier film and dries the weight obtained after surface electrolyte is weighed) it is more than 3, preferably more than 3.9.When imbibition ratio is the lowest, the speed of the most heat-resisting porous isolating membrane Electolyte-absorptive is relatively slow, and therefore ionic conductance reduces, and therefore battery efficiency declines.Additionally, the percent thermal shrinkage of the bearing of trend of heat-resisting porous isolating membrane is less than or equal to 5%.If shrinkage factor is the highest, then can improve and directly contact the short-circuit probability caused because of battery plus-negative plate.
In above-mentioned heat-resisting porous isolating membrane, the air penetrability (Gurley) of heat-resisting porous isolating membrane is 12 to 30 (sec/10ml), preferably 14 to 22 (sec/10ml).Air penetrability Ruo Taigao then can make the charge/discharge rates between battery too fast, easily causes battery explosion；If air penetrability is the lowest, the ion conduction rate in electrolyte can be affected so that battery efficiency reduces.
In above-mentioned heat-resisting porous isolating membrane, above-mentioned heat-resisting porous isolating membrane farther includes the second heat-resistant resin layer, and it is arranged at the second surface of base material, and second surface is relative with first surface.This second heat-resistant resin layer is by PVAA homopolymer, or the copolymer formed by PVAA and sodium acrylate is formed, but being not limited to this, it also can be the polymer such as polyimides, polyamide-imides, aromatic amides or polyphenylene sulfide.
In one embodiment of the invention, the base material of heat-resisting porous isolating membrane is polyacrylic single layered porous base material, and the heat-resistant resin layer on this base material is made up of policapram homopolymer, and its weight average molecular weight scope is 70 ten thousand to 80 ten thousand.
In another embodiment of the present invention, the base material of heat-resisting porous isolating membrane is polyacrylic single layered porous base material, the copolymer that heat-resistant resin layer on this base material is formed by PVAA and sodium acrylate is formed, and its weight average molecular weight scope is 70 ten thousand to 80 ten thousand.
Above-mentioned by policapram homopolymer, or the imbibition ratio of the heat-resisting porous isolating membrane of heat-resistant resin layer that the copolymer formed by PVAA and sodium acrylate is formed is more than 3.9, the percent thermal shrinkage of its bearing of trend is less than or equal to 3.0%, and air penetrability (Gurley) is 14 to 22 (sec/10ml).
The present invention also proposes the manufacture method of a kind of heat-resisting porous isolating membrane, and its step comprises: providing base material, this base material has loose structure；The heat stable resin solution that solid content is 1% to 7% is coated the first surface of base material to form the first heat-resistant resin layer, wherein, the heat stable resin of this heat stable resin solution is PVAA homopolymer, or is the copolymer of PVAA and sodium acrylate formation；It is dried the base material with the first heat-resistant resin layer to prepare heat-resisting porous isolating membrane.
This coating process can be avoided in prior art method, in order to improve the thermostability of isolating membrane, inorganic particulate is coated isolating membrane surface, and causes inorganic particulate to fall in electrolyte, thus results in the shortcomings such as the safety of battery is not enough.
In the manufacture method of above-mentioned heat-resisting porous isolating membrane, base material can be the loose structure base material of the single or multiple lift containing polyolefin, polyester or polyamide.
In the manufacture method of above-mentioned heat-resisting porous isolating membrane, the solid content of heat stable resin solution is 1% to 7%, preferably 2.5% to 5.0%.When the solid content too Gao Shihui of heat stable resin solution causes the hole of porous isolating membrane to block, affect ionic conductance and battery efficiency；If the solid content of heat stable resin solution is the lowest, then it is unable to reach heat-resisting effect so that the percent thermal shrinkage of prepared porous isolating membrane becomes big.
Heat stable resin solution is coated the mode of base material, can be selected for the coating process that this area is known, such as, can be impregnation rubbing method, slot coated method, roller rubbing method, intermittently rubbing method, method of spin coating, but be not limited to this.
In the manufacture method of above-mentioned heat-resisting porous isolating membrane, the solvent used in heat stable resin solution can be water, ethanol, isopropanol, ethylene glycol or a combination thereof.
In the manufacture method of above-mentioned heat-resisting porous isolating membrane, the weight average molecular weight scope of heat stable resin is 20 ten thousand to 150 ten thousand, preferably 70 ten thousand to 80 ten thousand.When the molecular weight of heat stable resin is the biggest, the processability of heat stable resin solution coating can be affected；When the molecular weight of heat stable resin is the least, heat-resisting effect can be caused the best, affect the heat shrinkability characteristic of heat-resisting porous isolating membrane.
In the manufacture method of above-mentioned heat-resisting porous isolating membrane, the imbibition ratio of heat-resisting porous isolating membrane is more than 3.9.When imbibition ratio is the lowest, the speed of the most heat-resisting porous isolating membrane Electolyte-absorptive is relatively slow, and therefore ionic conductance reduces, and battery efficiency declines.
The percent thermal shrinkage surveying bearing of trend in above-mentioned heat-resisting porous isolating membrane is less than or equal to 5%, preferably less than or equal to 3%.If on the contrary, the percent thermal shrinkage of heat-resisting porous isolating membrane is the highest, then can improve battery plus-negative plate and directly contact the short-circuit probability caused.
The air penetrability (Gurley) of heat-resisting porous isolating membrane is 12 to 30 (sec/10ml), preferably 14 to 22 (sec/10ml).If air penetrability too Gao Zehui makes the charge/discharge rates between battery too fast, easily cause battery explosion.If air penetrability is the lowest, the ion conduction rate in electrolyte can be affected so that battery efficiency reduces.
In the manufacture method of above-mentioned heat-resisting porous isolating membrane, comprise further and the heat stable resin solution that solid content is 1% to 7% is coated the second surface of base material to form the second heat-resistant resin layer, relative with regard to first surface in base material of the second surface of base material, and be dried the base material with this second heat-resistant resin layer to prepare heat-resisting porous isolating membrane.Wherein, the heat stable resin of this second heat-resistant resin layer is PVAA homopolymer, or be PVAA and the copolymer of sodium acrylate formation, but it being not limited to this, it also can be the polymer such as polyimides, polyamide-imides, aromatic amides or polyphenylene sulfide.
Following embodiment is used to further illustrate the present invention, but the present invention is not limited to this.
Embodiment 1
Take PVAA homopolymer aqueous solution 10 grams (poly (n-vinylacetamide) homopolymer) (trade name GE191 that weight percent concentration is 10%, weight average molecular weight scope is 70 ten thousand to 80 ten thousand, purchased from Japan Showa Denko) add in the ethanol of 30 grams, and be stirred at room temperature dissolving, to be configured to the PVAA homopolymer solution that solid content is 2.5%.Then, being applied to by PVAA homopolymer solution on the polypropylene film (trade name D1200, thickness is 19.5 μm, bright sill manufacture) of loose structure, to form heat-resistant resin layer, its thickness is 0.9 μm.Finally, being positioned in baking oven by the porous polypropylene film of tool heat-resistant resin layer, drying temperature is 80 DEG C, and drying time is 3 minutes, can be prepared by heat-resisting porous isolating membrane after drying.
From the difference of the porous isolating membrane of preparation in embodiment 1, the porous isolating membrane of preparation in embodiment 2 to embodiment 3, is only that the solid content of PVAA homopolymer solution and coating thickness are different.Composition in detail in embodiment 2 to embodiment 3 refer to table 1.
The porous isolating membrane of preparation in embodiment 4 to embodiment 5, it is with the difference of the porous isolating membrane of preparation in embodiment 1, the kind of the heat-resistant resin layer in embodiment 4 to embodiment 5 is copolymer (poly (n-vinylacetamide) and sodium acrylate comopolymer) (trade name GE167 that PVAA is formed with sodium acrylate, weight average molecular weight scope is 70 ten thousand to 80 ten thousand, weight percent concentration is 10%, purchased from Japan Showa Denko), and PVAA is dissolved in the solid content of solution formed after ethanol from the copolymer that sodium acrylate is formed and coating thickness is different.Composition in detail in embodiment 4 to embodiment 5 refer to table 1.
Comparative example 1 is commercially available product (purchased from Asahi Chemical Industry), and the matrix structure of its porous isolating membrane is porous polypropylene film base material, and thickness is 8 μm, and is coated with aluminium oxide particles in the side of this film substrate, and coating layer thickness is 8 μm.
Finally by the commercially available porous isolating membrane in the heat-resisting porous isolating membrane prepared in embodiment 1-embodiment 5 and comparative example 1, carrying out characteristic test respectively in accordance with following method of testing, test result refer to table 1.
The adhesive force test of heat-resistant resin layer and base material
Isolating membrane to be measured is positioned on test platform, is attached to the heat-resistant resin layer surface of isolating membrane with adhesive tape (3M Scotch600), the most again adhesive tape is torn up.If heat-resistant resin layer is fine with the adhesive force of base material, then after adhesive tape tears up, heat-resistant resin layer can be pulled up in the lump together with base material, and isolating membrane the most to be measured can crumple.If adhesive force is the best, the most only heat-resistant resin layer can be torn up by adhesive tape, and isolating membrane still maintains smooth state.Therefore can determine that heat-resistant resin layer is the best with the adhesive force of base material by the flat appearance degree of isolating membrane.
Imbibition ratio is tested
By the size that isolating membrane to be measured sanction is 6 cm x 6 centimetres, then weighing records weight is W1.Then isolating membrane to be measured is soaked and put 2 hours in the electrolytic solution.Electrolyte quota method is: ethylene carbonate (EC), methyl ethyl carbonate fat (EMC) and the dimethyl carbonate (DMC) ratio with percentage by weight as 1:1:1 are mixed to form mixed solution；Then, lithium hexafluoro phosphate (Lithium hexafluorophosphate) is dissolved in this mixed solution, to be configured to concentration 1M(molality, mol/kg) solution；Finally, add vinylene carbonate fat (VC) that percentage by weight is 1% relative to 1M solution, the making of electrolyte can be completed.Afterwards, isolating membrane to be measured is taken out from electrolyte and stands 30 seconds, then weighing records weight W2.The calculation of the imbibition ratio of this isolating membrane is (W2-W1)/W1.
Thermal contraction is tested
By the size that isolating membrane to be measured sanction is 10 cm x 10 centimetres, then record a length of L1 of bearing of trend (machine direction, MD).Then, isolating membrane to be measured is put in baking oven, toast 90 minutes under 130 DEG C of temperature conditionss.After 90 minutes, take out and measure length L2 of the bearing of trend (machine direction, MD) of isolating membrane to be measured, and calculate percent thermal shrinkage.The computing formula of the percent thermal shrinkage of isolating membrane is (L1-L2)/L1x100%.
Pierce through strength test
According to ASTM D3763 specification, puncture isolating membrane to be detected with the tylostyle of diameter 1mm, and measurement punctures maximum force needed for isolating membrane to be measured.
Air penetrability is tested
According to ASTM D-726 specification, Gurley Permeability gauge is utilized to measure 10ml air by the time needed for the isolating membrane to be measured of 0.00064516 square metre of size.
Table 1: embodiment 1-embodiment 5 forms and characteristic in detail with comparative example 1
From table 1, the characteristic test of isolating membrane can be learnt, heat-resisting porous isolating membrane proposed by the invention has good air penetrability, also there is the dimensional stability of excellence simultaneously, being embodied in it at the percent thermal shrinkage of bearing of trend is 2% to 3%, and it has good imbibition ratio for electrolyte, its imbibition ratio is 3.97 to 4.27.It follows that heat-resisting porous isolating membrane proposed by the invention is all better than porous isolating membrane commercially available in comparative example 1 in the performance of every characteristic.Additionally, due to utilize coating heat stable resin solution to form the mode of heat-resistant resin layer in substrate surface, significantly improve the adhesive force between heat-resistant resin layer and base material, therefore the situation that in comparative example 1, inorganic oxide aluminum particulate drops will not occur.Finally, heat-resisting porous isolating membrane proposed by the invention pierce through intensity also greater than 370gf, therefore it has higher mechanical strength, it is possible to meet in lithium ion battery preparation isolating membrane strength demand.
In sum, although the present invention is disclosed above with preferred embodiment, and so it is not limited to the present invention.Persond having ordinary knowledge in the technical field of the present invention, without departing from the spirit and scope of the present invention, when being used for a variety of modifications and variations, should belong to the protection domain of appended claims of the invention.
Claims (7)
1. a heat-resisting porous isolating membrane, for lithium ion battery, it is characterised in that comprise:
Base material, this base material has loose structure；
First heat-resistant resin layer, it is arranged at the first surface of this base material, and this first heat-resistant resin layer is made up of PVAA homopolymer or the copolymer that formed by PVAA and sodium acrylate,
Wherein, this first heat-resistant resin layer is to be formed by the heat stable resin solution of solid content 1% to 7%, the weight average molecular weight scope of the heat stable resin forming this first heat-resistant resin layer is 20 ten thousand to 150 ten thousand, the imbibition ratio of this heat-resisting porous isolating membrane is more than 3.0, and the percent thermal shrinkage of the bearing of trend of this heat-resisting porous isolating membrane is less than or equal to 5%；The air penetrability of this heat-resisting porous isolating membrane is 12 to 30 (sec/10ml).
2. the heat-resisting porous isolating membrane as described in claim 1, it is characterised in that this base material is the loose structure base material of the single or multiple lift containing polyolefin, polyester or polyamide.
3. the heat-resisting porous isolating membrane as described in claim 1, it is characterized in that, also include the second heat-resistant resin layer, this the second heat-resistant resin layer is arranged at the second surface of this base material, wherein, this second surface is relative with this first surface, and this second heat-resistant resin layer is made up of PVAA homopolymer or the copolymer that formed by PVAA and sodium acrylate.
4. a manufacture method for heat-resisting porous isolating membrane, this heat-resisting porous isolating membrane is used for lithium ion battery, it is characterised in that this manufacture method comprises:
Thering is provided base material, this base material has loose structure；
The heat stable resin solution that solid content is 1% to 7% is coated the first surface of this base material to form the first heat-resistant resin layer, the heat stable resin forming this heat stable resin solution is PVAA homopolymer, or is the copolymer of PVAA and sodium acrylate formation；
It is dried this base material with this first heat-resistant resin layer to prepare this heat-resisting porous isolating membrane；
Wherein, the weight average molecular weight scope of this heat stable resin is 20 ten thousand to 150 ten thousand；The imbibition ratio of this heat-resisting porous isolating membrane is more than 3.0, and the percent thermal shrinkage of the bearing of trend of this heat-resisting porous isolating membrane is less than 5%；The air penetrability of this heat-resisting porous isolating membrane is 12 to 30 (sec/10ml).
5. the manufacture method of the heat-resisting porous isolating membrane as described in claim 4, it is characterised in that the solvent used in this heat stable resin solution is water, ethanol, isopropanol, ethylene glycol or a combination thereof.
6. the manufacture method of the heat-resisting porous isolating membrane as described in claim 4, it is characterised in that this base material is the loose structure base material of the single or multiple lift containing polyolefin, polyester or polyamide.
7. the manufacture method of the heat-resisting porous isolating membrane as described in claim 4, it is characterised in that also include:
The heat stable resin solution that solid content is 1% to 7% is coated the second surface of this base material to form the second heat-resistant resin layer, wherein, this second surface is relative with this first surface, the heat stable resin forming this second heat-resistant resin layer is PVAA homopolymer, or is the copolymer of PVAA and sodium acrylate formation；And
It is dried this base material with this second heat-resistant resin layer to prepare this heat-resisting porous isolating membrane.
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|---|---|---|---|---|
| JP5005137B2 (en) * | 2001-07-12 | 2012-08-22 | 昭和電工株式会社 | Zinc secondary battery separator and zinc secondary battery using the same |
| JP5259721B2 (en) * | 2009-03-13 | 2013-08-07 | 日立マクセル株式会社 | Battery separator and non-aqueous electrolyte battery using the same |
-
2014
- 2014-03-21 CN CN201410108758.7A patent/CN103972449B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN103972449A (en) | 2014-08-06 |
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