Background technology
Polymer lithium-ion battery not only has the characteristics of high voltage, high-energy-density, long circulation life and the cleanliness without any pollution of liquid lithium ionic cell, and be solid-state structure because of it, take flexible package, also have characteristics such as configuration design is flexible and changeable, thickness is thinner, fail safe is better.Polymer lithium-ion battery has been used for various novel mobile phone products, becomes the another focus of chemical power source research in recent years.The key technology of polymer lithium-ion battery is the preparation polymer electrolyte diaphragm.U.S. Bellcore company in 1993 is that matrix is developed ionic conductivity height, porous polymer electrolyte that mechanical strength is good with vinylidene fluoride and hexafluoropropylene copolymer, but this arts demand extraction plasticizer, the production technology relative complex, and the production cost height is not easy to realize plant-scale manufacturing.
Polyethene microporous membrane melts between 120~130 ℃, and its characteristics of closing in early days make the increase be easy to suppress the associated temperature of closing with micropore, but in single barrier film of being made by polyethylene, its film rupture temperature is also low, thereby can not think that it is safe.Patent CN99804321 adopts HDPE and atoleine blend, 131.9 ℃ of gained microporous membrane closed pore temperatures, and 133.1 ℃ of film rupture temperature, the fail safe of battery is relatively poor.Recently also adopt laminated film but not the homogenous material film solves the safety issue of barrier film.The patent that Tonen, Asahi-Kasei, Hoechst company have applied for two-layer PE/PP and three layers of PP/PE/PP microporous barrier.Patent CN92109189 has provided the microporous barrier that is made of polyethylene and polypropylene, and its closed pore temperature is 135~140 ℃, and the temperature of film rupture is near 170 ℃, and both differ 30~35 ℃, have very high security performance.But these laminated films all adopt the fusion drawn method to make.The fusion drawn method is earlier with crystalline polymer extrusion molding film forming under the condition that improves molten polymer stress, make film under no tension force or low-tension, obtain the necessary crystallization structure then through annealing, after carry out the network structure that longitudinal stretching produces a kind of slit-shaped space.Therefore there are shortcomings such as aperture and the difficult control of porosity in these laminated films, and owing to only carry out longitudinal stretching, the film transverse strength is relatively poor.
Nickel-based battery is the novel secondary cell that development in recent years is got up, have the specific energy height, battery capacity is big, can reach 1.5-2 times with volume good fortune nickel-based battery, overcharging resisting, discharge, be not afraid of characteristics such as abuse, and can exchange with the good fortune nickel-based battery, charger need not to do any change and can use, main is that it does not exist as the pollution of heavy metals such as pot, mercury to environment, is referred to as " green power supply ".Therefore, the development of nickel-based battery in recent years is very rapid, progressively replaces the good fortune nickel-based battery, just is being widely used in the electronic apparatuss such as portable computer, cordless telephone, mobile phone, video camera.In above-mentioned nickel secondary batteries, barrier film is one of its crucial part, except that playing the effect of isolating both positive and negative polarity, also must have the ability and the excellent chemical stability of good absorption alkaline electrolyte.Nickel-based battery in the past, its barrier film adopt good vinylon barrier film of hydrophily and poly-phthalein amine fibre diaphragm usually, yet the oxidation resistance of vinylon is relatively poor, cause the performance of battery to be subjected to very big influence.The Fypro barrier film can hydrolysis generate for example impurity such as nitrate ion, nitrite ion, ammonia in aqueous slkali, the existence of these impurity causes the self discharge of battery to increase equally, and it is bad that the performance of battery obviously becomes.
Summary of the invention
Purpose of the present invention is exactly the defective that exists in the above-mentioned prior art for overcoming, and a kind of sulphur-modified polyolefin battery separation film is provided, the present invention with common polyalkene diaphragm sulfonation after, ionic conductivity is good, alkali absorbing rate is high, oxidation resistance is strong.
Another object of the present invention provides the preparation method of above-mentioned sulphur-modified polyolefin battery separation film.
Total institute is known, and unmodified polyolefin is hydrophobic, and since its proportion less than 1, fiber can be kept afloat when wet method was manufactured paper with pulp, and had more increased the difficulty of manufacturing paper with pulp.Therefore, at first need polyolefin is carried out hydrophilic modifying.In order to reduce the speed of homopolymerization as far as possible, it is necessary adding polymerization inhibitor, and this class material with polymerization inhibition effect mainly contains ferrous sulfate, ferric sulfate, copper sulphate, ferrous sulfate by with copper acetate etc.The concentration of polymerization inhibitor just can make homopolymerization obtain more effectively containing in a certain suitable scope, and the speed of graft copolymerization is then influenced not quite.
For reaching above-mentioned purpose, the concrete technical scheme that the present invention takes is as follows:
A kind of sulphur-modified polyolefin battery separation film, the weight proportion of its raw material is: polypropylene or polyethylene fibre 60-90%, grafted monomers acrylic acid, methacrylic acid, propylene phthalein amine or metering system phthalein amine 2~10%, enhanced fiber 5-15%, sulfonating agent 1-10%.
Above-mentioned sulphur-modified polyolefin battery separation film, one of preferred scheme is: sulfonating agent removes conventional sulfonating agent, as sulfuric acid, chlorosulfonic acid, sulfur trioxide etc., can also adopt gentle sulfonating agents such as sulphonic acid ester.The consumption of sulfonating agent is preferably 1-6%.
Above-mentioned sulphur-modified polyolefin battery separation film, two of preferred scheme is: enhanced fiber is the composite fibre of polypropylene cores and polyethylene sheath.
The preparation method of above-mentioned improved polyalkene diaphragm comprises following processing step:
A, grafted monomers is mixed with the aqueous solution, adds polymerization inhibitor simultaneously;
B, polyethylene or polypropylene fibre and sulfonating agent are joined in the above-mentioned solution, in the graft reaction device of packing into after the mixing, feed protective gas, gamma ray or ultraviolet ray or high-energy electron beam irradiation carry out graft copolymerization to polyolefine fiber;
C, with the graft-modified polyolefin fiber after washing, be ferreted out battery diaphragm with wet method, carry out press polish and ornamenting at last and handle.
Above-mentioned protective gas preferably feeds high pure nitrogen, time 20-30 minute.
The manufacture method of above-mentioned improved polyalkene diaphragm, grafted monomers are preferably methacrylic acid or propylene phthalein amine, or its mixture.
The manufacture method of above-mentioned improved polyalkene diaphragm, also comprise the adding bonding agent, the bonding agent that uses can be one or more the mixture in polyacrylic acid first vinegar, polyacrylic acid second vinegar, polyvinyl alcohol, poly-methyl methacrylate vinegar, polymethylacrylic acid second vinegar, the shuttle methylcellulose.
Beneficial effect of the present invention: the polyolefine fiber after the graft modification is after washing, has good hydrophilicity, and in water, be uniformly dispersed, slurry system is stable, be equipped with the fiber of a certain proportion of increase paper strength again, adopt the wet method speciality paper equipment of the manufacturing paper with pulp above-mentioned diaphragm paper of just can manufacturing paper with pulp out, and, make diaphragm paper can satisfy the thickness requirement that battery assembles through appropriate postprocessing.By the polyolefine fiber diaphragm paper that the inventive method is made, ionic conductivity is good, liquid-keeping property is strong, alkali absorbing rate is high, chemical stability is good, oxidation resistance is strong, can obviously improve the electrical property of nickel-based battery.
Embodiment
Following embodiment is to further explanation of the present invention and explanation, and the present invention is not constituted any limitation.
Embodiment 1
By methacrylic acid: it is 40% the aqueous solution that acrylamide=1: 0.8 is mixed with total concentration, add copper acetate simultaneously as polymerization inhibitor, inhibitor concentration is 0.4%, with polypropylene fibre in fiber: the ratio of solution=1: 8 joins in the above-mentioned reaction liquid, in the graft reaction device of packing into after fiber and liquid and the mixing of sulfonating agent chlorosulfonic acid, logical high pure nitrogen 25 minutes.After total metering is for 6KGY irradiation, make polyolefine fiber obtain lasting hydrophily.Above-mentioned modified fibre is after washing, by length is the graft-modified polyolefin fiber 60% of Slnln, length is polypropylene cores, the polyethylene sheath composite fibre 30% of 8mm, the proportioning of poly-methyl methacrylate cruel 10%, adopt the wet method speciality paper equipment of manufacturing paper with pulp to be ferreted out diaphragm paper, and handle through suitable press polish and ornamenting.
Embodiment 2
By methacrylic acid: it is 50% the aqueous solution that metering system phthalein amine=1: 1 is mixed with total concentration, add ferrous sulfate simultaneously by as polymerization inhibitor, inhibitor concentration is 0.5%, with polypropylene fibre in fiber: the ratio of solution=1: 9 joins in the above-mentioned reaction liquid, splash into the sulfonating agent chlorosulfonic acid at last, react completely logical high pure nitrogen 30 minutes.After total metering is for 7KGY irradiation, make polyolefine fiber obtain lasting hydrophily.Above-mentioned modified fibre is after washing, by length is the graft-modified polyolefin fiber 60% of 2mm, length is polypropylene cores, the polyethylene sheath composite fibre 20% of Slnfn, the proportioning of polymethylacrylic acid second cruel 20%, adopt wet temple, the continent kind paper equipment of manufacturing paper with pulp to be ferreted out diaphragm paper, and handle through suitable press polish and ornamenting.
Embodiment 3
It is 20% the aqueous solution that acrylic acid is mixed with concentration, add ferrous sulfate, ferric sulfate simultaneously as polymerization inhibitor, inhibitor concentration is 0.2%, with the composite fibre of polypropylene fibre, polyethylene fibre in this composite fibre: the ratio of solution=1: 10 joins in the above-mentioned reaction liquid, splash into sulfonating agent sulfuric acid at last, react completely, in the graft reaction device of packing into after fiber and the liquid mixing, logical high pure nitrogen 30 minutes.After total metering is for SKGY irradiation, make polyolefine fiber obtain lasting hydrophily.Above-mentioned modified fibre is after washing, by length is the graft-modified polyolefin fiber 60% of 6Inln, length is polypropylene cores, the polyethylene sheath composite fibre 35% of 6mm, the proportioning of shuttle methylcellulose 5%, adopt the wet method speciality paper equipment of manufacturing paper with pulp to be ferreted out diaphragm paper, and handle through suitable press polish and ornamenting.
Embodiment 4
Being mixed with concentration by methacrylic acid is 40% the aqueous solution, add copper sulphate, ferrous sulfate money simultaneously as polymerization inhibitor, inhibitor concentration is 0.5%, with polypropylene fibre in fiber: the ratio of solution=1: n joins in the above-mentioned reaction liquid, after fiber and liquid mixing, splash into the sulfonating agent chlorosulfonic acid, react completely, pack in the graft reaction device, led to high pure nitrogen 50 minutes.After total metering is for 10KGY irradiation, make polyolefine fiber obtain lasting hydrophily.Above-mentioned modified fibre is after washing, by length is the graft-modified polyolefin fiber 70% of 7mm, length is polypropylene cores, the polyethylene sheath composite fibre 38% of 7Inln, the proportioning of the mixture 2% of polyacrylic acid first vinegar and polyacrylic acid second vinegar, adopt the wet method speciality paper equipment of manufacturing paper with pulp to be ferreted out diaphragm paper, and handle through suitable press polish and ornamenting.
Embodiment 5
By methacrylic acid: it is 10% the aqueous solution that acrylic acid=1: 0.8 is mixed with methacrylic acid and acrylic acid total concentration, add ferrous sulfate simultaneously as polymerization inhibitor, the concentration of polymerization inhibitor in solution is 0.1%, with the composite fibre of polypropylene fibre, polyethylene fibre in this composite fibre: the ratio of solution=1: 5 joins in the above-mentioned reaction liquid, after this composite fibre and liquid mixing, splash into the sulfonating agent sulphonic acid ester at last, react completely, pack in the graft reaction device, led to high pure nitrogen 10 minutes.After total metering is for ZKGY irradiation, make polyolefine fiber obtain lasting hydrophily.Above-mentioned modified fibre is after washing, by length is the graft-modified polyolefin fiber of 2mm, and length is polypropylene cores, the polyethylene sheath composite fibre 40% of Zmm, the proportioning of polyacrylic acid first cruel 20%, adopt the wet method speciality paper equipment of manufacturing paper with pulp to be ferreted out diaphragm paper, and handle through suitable press polish and ornamenting.
Embodiment 6
By propylene phthalein amine: acrylic acid=1: 1 be mixed with the propylene reward by with the acrylic acid total concentration be 30% the aqueous solution, add ferric sulfate simultaneously as polymerization inhibitor, the concentration of polymerization inhibitor in solution is 2%, with polypropylene fibre in fiber: the ratio of solution=1: 6 joins in the above-mentioned reaction liquid, after fiber and liquid mixing, go into the sulfonating agent sulfur trioxide at last, react completely, pack in the graft reaction device, led to high pure nitrogen 15 minutes.After total metering is for 4KGY irradiation, make polyolefine fiber obtain lasting hydrophily.Above-mentioned modified fibre is after washing, by length is the graft-modified polyolefin fiber 50% of 3mm, length is polypropylene cores, the polyethylene sheath composite fibre 30% of 3mm, the proportioning of polyacrylic acid second vinegar 20%, adopt the wet method speciality paper equipment of manufacturing paper with pulp to be ferreted out diaphragm paper, and handle through suitable press polish and ornamenting.
Embodiment 7
By the methacrylic acid amino acid: it is 20% the aqueous solution that acrylic acid=1: 1.2 is mixed with total concentration, add copper sulphate simultaneously as polymerization inhibitor, inhibitor concentration is 0.3%, with the composite fibre of polypropylene fibre, polyethylene fibre in this composite fibre: the ratio of solution=1: 7 joins in the above-mentioned reaction liquid, after fiber and liquid mixing, splash into the sulfonating agent chlorosulfonic acid at last, react completely, pack in the graft reaction device, led to high pure nitrogen 20 minutes.After total metering is for SKGY irradiation, make polyolefine fiber obtain lasting hydrophily.Above-mentioned modified fibre is after washing, by length is the graft-modified polyolefin fiber 50% of 4mm, and length is polypropylene cores, the polyethylene sheath composite fibre 40% of 4mm, the proportioning of polyvinyl alcohol 10%, adopt the wet method speciality paper equipment of manufacturing paper with pulp to be ferreted out diaphragm paper, and handle through suitable press polish and ornamenting.
Embodiment 8
It is 30% the aqueous solution that propylene phthalein amine is mixed with concentration, add ferrous sulfate, copper acetate simultaneously as polymerization inhibitor, inhibitor concentration is 1%, with polypropylene fibre in fiber: the ratio of solution=1: 12 joins in the above-mentioned reaction liquid, after fiber and liquid mixing, splash into the sulfonating agent chlorosulfonic acid at last, react completely, the graft reaction device of packing into, logical high pure nitrogen 60 minutes.After total metering is for 6KGY irradiation, make polyolefine fiber obtain lasting hydrophily.Above-mentioned modified fibre is after washing, by length is the graft-modified polyolefin fiber 70% of 2mm, length is polypropylene cores, the polyethylene sheath composite fibre 20% of 2mm, the proportioning of the mixture 10% of polyvinyl alcohol and poly-methyl methacrylate vinegar, adopt the wet method speciality paper equipment of manufacturing paper with pulp to be ferreted out diaphragm paper, and handle through suitable press polish and ornamenting.
Embodiment 9
It is 30% the aqueous solution that metering system phthalein amine is mixed with concentration, add ferrous sulfate, ferric sulfate, copper sulphate simultaneously as polymerization inhibitor, inhibitor concentration is 0.3%, with the composite fibre of polypropylene fibre, polyethylene fibre in this composite fibre: the ratio of solution=1: 13 joins in the above-mentioned reaction liquid, after fiber and liquid mixing, packing into to connect splashes into the sulfonating agent chlorosulfonic acid at last, reacts completely, in the branch reactor, logical high pure nitrogen 35 minutes.After total metering is for 3KGY irradiation, make polyolefine fiber obtain lasting hydrophily.Above-mentioned modified fibre is after washing, by length is the graft-modified polyolefin fiber 70% of 6mm, length is polypropylene cores, the polyethylene sheath composite fibre 10% of 6mm, the proportioning of the mixture 20% of polymethylacrylic acid second vinegar and shuttle methylcellulose, adopt the wet method speciality paper equipment of manufacturing paper with pulp to be ferreted out diaphragm paper, and handle through suitable press polish and ornamenting.
Embodiment 10
It is 25% the aqueous solution that metering system phthalein amine is mixed with concentration, add ferrous sulfate, ferric sulfate, copper sulphate, ferrous sulfate money, copper acetate simultaneously as polymerization inhibitor, inhibitor concentration is 0.5%, with the composite fibre of polypropylene fibre, polyethylene fibre in this composite fibre: the ratio of solution=1: 15 joins in the above-mentioned reaction liquid, after fiber and liquid mixing, splash into the sulfonating agent chlorosulfonic acid at last, react completely, pack in the graft reaction device, led to high pure nitrogen 45 minutes.Behind irradiation, make polyolefine fiber obtain lasting hydrophily.Above-mentioned modified fibre is after washing, by length is the graft-modified polyolefin fiber 90% of 9mm, length is polypropylene cores, the polyethylene sheath composite fibre 5% of 9mm, the proportioning of the mixture 15% of the cruel and polymethylacrylic acid second vinegar of poly-methyl methacrylate, adopt the wet method speciality paper equipment of manufacturing paper with pulp to be ferreted out diaphragm paper, and handle through suitable press polish and ornamenting.