TW200838015A - Binder for electrodes of condenser - Google Patents

Abstract

Disclosed is a binder for capacitor electrodes, which has a high binding characteristic with a powder electrode material and a high adhesive characteristic to a collector electrode. The binder also has excellent conductivity and wettability to an electrolytic solution, in a status where the powder electrode material is bound, i.e., in a status of an electrode sheet, and a high heat resistance. The binder is electrochemically stable and is composed of an aramid granulated by heating.

Description

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As the symbol of recent advances in mobile devices and high-speed information processing machines, the small size, light weight and high performance of electronic devices are attracting attention. The two pairs of small, lightweight, high-capacity capacitors that are resistant to long-term storage have a large expectation, and have been widely used, and parts development is urgent. In order to cope with this situation, the necessity of developing the technique and quality of the adhesive for bonding the electrode active material to the electrode sheet is also improved. In particular, for the adhesives for electrodes in capacitors requiring high withstand voltage, large capacity, large output capacitors, batteries, etc., among the various characteristics required for the adhesive, the following five characteristic items are particularly important: 1)黏 粕 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极 电极That is, the wettability to the electrolyte in the state of the electrode sheet is good; 4) the heat resistance is high; 5) it is electrochemically stable. "First Rain" as a binder, widely used PVdF (polyvinylidene fluoride, Polyvmyhdene Flu〇ride), pTFE (polytetrafluoroethylene, P〇lytetrafluorethyiene), SBR (styrene butadiene rubber, 127610.doc 200838015 Butadiene ^r) |L^ # #j^ ^ ^ In recent years, high voltage resistance, large capacity, and large output required for capacitors and batteries for electric vehicles have not been fully met. One of the specific characteristics is a high-temperature drying of an electrode group including a collector electrode, an electrode, and an isolator previously proposed by the present inventors (refer to Japanese Patent Application No. 2006_073898). Moreover, it is difficult to produce a thin electrode sheet, and it is sometimes difficult to apply it; a capacitor and a battery having a large output of a thin electrode are required. Further, in order to provide a secondary battery negative electrode active material having high charge and discharge efficiency, for example, a ruthenium polyamine (aromatic polyamine) is used as a secondary material, as disclosed in Japanese Laid-Open Patent Publication No. JP-A No. Hei. The negative electrode active material-bonding agent for a battery is used for the negative electrode active material-bonding agent for a secondary battery, and the organic polymer having an electrochemically active group on the main chain or the side chain is used for the portion of the negative electrode active material. . However, since it is difficult to ensure the adhesion of the powder electrode material and the adhesion to the collector at the same time and the lower conductivity in the state of the electrode sheet, the desired battery characteristics may not be obtained. SUMMARY OF THE INVENTION The main object of the present invention is to provide an adhesive for an electrode for an electric storage device, which exhibits a high adhesion of a powder electrode material and a state in which a collector electrode is followed by a powder electrode material, that is, an electrode. The sheet has excellent conductivity and wettability to the electrolyte, high heat resistance, and electrochemical stability. Still another object of the present invention is to provide an electric storage device such as an electric grid or a battery using the above-mentioned binder. 127610.doc 200838015 Regulations: The results of intensive studies conducted to achieve the above objectives are found in the electricity = the use of aromatic polyamines granulated by heat treatment as the electrode for extreme use. It is effective to complete the present invention. Thus, the present invention provides a binder for an electric storage electrode comprising an aromatic polyamine which is granulated by heat treatment. Further, the present invention provides a bismuth electrode sheet which is produced by mixing a powder electrode material, a binder and a solvent with a water sputum and coating the slurry on a collector. The Nanxun Xinxiang mouth brake is a square polyamine, and the above electrode sheet is obtained by heat treatment after coating. The present invention further provides an electric storage device using the above electrode sheet, and more particularly to provide a capacitor and a battery. The adhesive of the present invention is an aromatic polyamine which has high heat resistance and is electrochemically stable, and is bonded by a binder. During the granulation process caused by heat treatment, shrinkage stress is generated between the materials of the electrode, and the portion covering the surface of the powder electrode material is reduced by shrinkage, so the contact area between the powder electrode materials is increased, and the state of the electrode sheet is increased. Further, in the adhesive of the present invention, the aromatic polyamine has a mercapto group in the molecular chain, so that the wettability of the electrolyte having a carboxyl group in the molecule is good, and Since the electrode sheet can be produced by the coating method, a thin electrode sheet can be produced, and thus it is most suitable for a capacitor, a battery, and the like which require a large output of a thin electrode. [Comprehensive method] Hereinafter, the present invention is further provided. Detailed Description Powder Electrode Material: 127610.doc 200838015 The powder electrode material of the present invention contains an electrode active material and, if necessary, added conductive An electrode active material used in the present invention is not particularly limited as long as it can function as a capacitor crying and/or an electrode of a battery, and: In the case of a capacitor, for example, activated carbon, blister carbon, carbon nanotubes, polyterpene benzene, or the like, which is used to effectively distinguish the electric double layer discovered in the (fourth) year, etc.; Materials, · accompanying redox reactions, anti-specific metal oxides, conductive polymers, electrodes for wide-area use can use the electrodes of the battery, and in the battery soil for the monolithic battery, the main taste, For &, Yuba lithium ion secondary n " ' ^ for the positive electrode, for example, lithium cobaltate, lithium chromate vanadate lithium, lithium chromate, nickel acid clock " as a warehouse ^ manganese lanthanum lithium lanthanum Metal oxide, etc. =: If natural graphite, artificial graphite, ..., stone reversal, petroleum coke, octacarbon microspheres and other carbon materials, metal lithium, etc., Γ, / J J coke, intermediate Phase-lead conductive agent: Conductive used in the present invention The functional position of the Qibu rate is no special duty = conductive black of π electrode #, carbon black of Ketchen black, etc. As a preferred one, for example, acetylene aromatic poly ugly amine: the above system used in the present invention Directly bonded to an aromatic/amine, 'containing a guanamine bond' (4), for example, can be exemplified by a poly-molecular linear two-molecule compound 'specifically, an I-diamine and its copolymer, poly-pair 127610.doc 200838015 Benzyldiphenyl phthalamide and copolymers thereof, and poly(p-phenylenediyl)-co-(3,4-diphenyl ether)terephthalamide, etc. The aromatic polyamines can be, for example, It is industrially produced by an interfacial polymerization method or a solution polymerization method known per se using isophthalic acid chloride and m-phenylenediamine, and can be obtained as a commercial product, but is not limited thereto. Among the polyamines, particularly preferred is poly(m-phenylenediphenyl)m-benzoic acid, which has good moldability, thermal adhesion, flame retardancy, heat resistance and the like.芳 Aromatic polyamide granulated by heat treatment: An aromatic polyamine which is granulated by heat treatment can be prepared, for example, by mixing a powder electrode material, an aromatic polyamine, and a solvent. The slurry was obtained by coating the slurry on a collecting electrode and heating it. The aromatic polyamine in the coating film is in the form of a tree as shown in Fig. i before being heated after coating, and when it is heated, for example, under 3 thieves for 2 hours, it becomes granular as shown in Fig. 2 . The aromatic polyamine shrinks during the process of becoming granular, and shrinkage stress is generated between the powder electrode materials, and the portion covering the surface of the powder electrode material becomes smaller due to shrinkage, so the contact area between the powder electrode materials increases' and The characteristics of the electric storage device: the electrode plate is highly conductive and the resistance value is lowered, and the β + is low, and the granulated polyglycolamine has a high adhesive force because the # U Λ is impregnated in the electrolyte. ^, the resistance of the livestock electrical appliances is still kept low. "In the present invention, as far as the amount of the aromatic polyamine binder is used, as long as the temperature is changed from heating to granular, there is no particular =/, the total amount of the electrode material of the final electrode material and the powder half It is known that the use of polyamine adhesives is in the range of 3 to 15 wt%, especially in the range of 5 to 13 wt% of fresh and bismuth. Also in the above range, then 127610.doc 200838015 will often be difficult to cause granulation 'as shown in Figure 3 and Figure 4, at 35 (after heating under the armpit 2%, the adhesive will cover the powder electrode material, resulting in The function of the electric storage device is remarkably lowered. As far as the above heat treatment conditions are concerned, as long as the desired electric storage device can be achieved, it is preferable that the heat treatment is close to the crystallization temperature of the aromatic polyamide. The reason for this is that the (4) polybenzamide has the highest adhesive force. For example, when using a poly(m-phenylene diphenyl) group (the benzodiazepine as the aromatic polyamine), if it exceeds 370. Thermal decomposition also occurs, so it is preferred that the 'heat treatment is at 37 〇. From the viewpoint of crystallization temperature, it is particularly preferable to carry out q at a temperature in the range of 330 to 3 steps, and the point of heat treatment is as long as it is after coating. It is not particularly limited, and preferably, after coating, temporary drying is carried out at a relatively low temperature close to the solvent point, and after the solvent is removed, heating is performed immediately, so that the solvent is bumped. The foaming caused does not impede the characteristics of the electric storage device. As the heating side C, for example, a method of performing hot pressing at a high temperature and a high pressure between a pair of flat plates or a metal system can be cited. For the conditions of hot pressing, for example, metal is used. In the case of the roll, the temperature may be exemplified by the temperature of 275 to 3, and the line pressure is 5 〇, and is not limited to these conditions, and may be simply heated without performing a pressurization operation. A plurality of electrode sheets may be laminated, and further, the collector, the electrode and the separator plate may be mounted as an electrode unit in a plurality of times in any order. Further, as the electrode unit, as long as the electrode unit is provided The electrode and the isolator are assembled and the 127610.doc -10 - 200838015 is not particularly limited. For example, it can be stacked in the order of the city electrode/electrode/isolator/electrode/collector, or fly M-pole /The electrode/electrode/isolator/electrode/collector/electrode/isolator are stacked in sequence, or the stacking is repeated, or the stacked body thus stacked is rolled up to assemble the unit. At this time, it is also possible to borrow in advance. It is followed by an adhesive or the like and then between the members. , '' Solvent:

The solvent used in this paragraph, only respects <,: A /, 罟疋 可, 合解方聚聚胺

It can be used without any particular limitation, among which Yudou County, a good 疋 is a good solvent, DMA-dimethylacetamide (DMAC, dimethyiacetamide), methyl 2-pyrrolidone (NMP, N_Methyl_2_pyrr〇Hd 〇ne) is the mixture of the specialties. Collector: The collector electrode to be used in the present invention is not particularly limited as long as it contains a conductive material and is stable with respect to an electrode, a solvent, and an electrolytic solution, and examples thereof include a thin plate, a thin plate, and a thin copper plate. Wait for a thin metal plate. The electrode sheet: = the electrode sheet of the order " can be produced, for example, by preparing a slurry in which a powder electrode material, an aromatic polyamide adhesive, and a solvent are mixed, coating the slurry on a collecting electrode, and then performing heat treatment. Specifically, it can be produced, for example, in the same manner. A slurry preparation step: An aromatic polyamine solution is prepared by dissolving an aromatic polyamine in a solvent. This/liquid mixture was mixed with a powder electrode material and stirred to prepare a uniform slurry. ' 127610.doc -11 - 200838015 2) Thick sheet production step: The above slurry is applied to one side or both sides of the collector using an E-material coating device such as a doctor blade, for example, by a continuous drying furnace or by stationary drying. In the furnace, dry and solidify to make thick slabs. The drying temperature at this time is within the range of 佛 谷 谷 谷 彳 5 5 5 5 5 5 5 5 5 。 。 。 。 。 。 。 。 3) Pressing step: ' f

The obtained sheet is hot-pressed at a high temperature and a high pressure, for example, between a pair of flat plates or a metal roll, whereby the density and mechanical strength of the sheet can be improved. The pressed electrode sheet preferably satisfies the range shown by the following formula (1). 0.25<Dx(i/D-We/De-Wc/Dc-Wb/Db)<〇.75.. (1) where D is the density of the electrode sheets after the collector is removed,

We are the weight fraction of the electrode active material,

De is the true specific gravity of the electrode active material,

Weight fraction of Wc conductive agent,

The true specific gravity of Dc conductive agent,

Wb-based adhesive weight fraction, D b-based adhesive true weight. When Dx (l/D-We/De-Wc/Dc-Wb/Db) is 〇·75 or more, the electrode sheet cannot be sufficiently densified, and it is difficult to obtain a sufficient capacitance as a capacitor or a battery. On the other hand, when Dx (1/D_We/De_Wc/Dc_wb/Db) is 0.25 or less, the electrode sheet is excessively high in density, so that it is difficult to obtain a sufficient output as a battery. EXAMPLES 127610.doc -12- 200838015 The following is a detailed description of the invention. Further, the embodiments are merely illustrative and are not intended to limit the scope of the invention. Reference Example 1 (Production of Electrode Sheet) 1) Slurry preparation step: Poly(m-phenylene isophthalamide) (true specific gravity 1.38) was dissolved in NMP to prepare an inter-aromatic polyamine solution. The above > trough liquid and activated carbon (Rp_2〇, manufactured by Kuraray_c Co., Ltd.) and Koryo

The black was mixed and stirred to prepare a homogeneous slurry. The ratio of the mixture was adjusted to .NMP after the treatment, the activated carbon: Ketjen black: poly(m-phenylene diphenyl phenylenediamine = 85: 5: 1 重量 weight ratio. 2) Electrode piece making steps: Use the knife, at! The slurry obtained above is coated on one side of the luminal collector (previously coated with a conductive resin), dried ((10), c, minute, normal pressure, atmospheric environment), and then pressed and dried (temperature 17 〇t) The pressure is squeezing below, 1 hour), and an electrode sheet having a thickness of 93 μm is obtained. Reference Example 2 (Production of Electrode Unit) An isolator containing an inter-aromatic polyamine and a para-polyamine was prepared according to the description of the examples of Japanese Patent Laid-Open Publication No. (24.4 g/base weight) M2, the thickness 46 is melon, 宓 η 〇, 3, μΠ1 at a degree of 0·53 g/cm 3 ), and the positive and negative electrodes j are sandwiched between the above electrode sheets to obtain an electrode unit. Example 1 After referring to Reference Example 2 at a temperature of 350 ° C (pressure 1 Torr or less, 12 hours), it was inserted into an aluminum foil laminate outer casing. The electrode unit produced is then dried in a dry environment, and the three sides of the outer surface are sealed in the form of 127610.doc -13 - 200838015, and injected into the TMABF4/PC of 1·5 ( (dissolved in propylene carbonate). A solution having triethylmethylammonium or tetrafluoroborate was used as an electrolytic solution, and was subjected to reduced pressure impregnation, and the remaining side of the exterior was pressure-sealed to form a capacitor having the composition shown in Table 1 below. Comparative Example 1 A capacitor having the structure shown in Table 1 was produced in the same manner as in Example 1 except that the temperature of the heat treatment of the electrode unit produced in Reference Example 2 was changed to 150 °C. The heat treatment at this time is carried out by drying the activated carbon electrode, and the heating temperature to which the adhesive after application is applied is up to 170 ° C in the electrode sheet production step. Table 1: Capacitor Structure Electrode Composition wt% Activated Carbon/KB/Aromatic Polyamide = 85/5/10 Thickness μιη 93 Density g/cm3 0.6 Dimensions (L x W) mmxmm 50x30 Collector Material Aluminum Thickness μιη 40 Isolator Composition wt% intermetallic polyamide / para-aramid = 50 / 50 basis weight g / cm 2 24.4 thickness μιη 46 density g / cm3 0.53 size (length x width) mmxmm 53x33 electrolyte composition 1.5M-TEMABF4 / PC exterior material aluminum type lamination <characteristic evaluation> The initial characteristics, rate characteristics, and low temperature characteristics of the above capacitor were measured by the following methods. 1) Initial charge and discharge characteristics 127610.doc -14- 200838015 As an initial characteristic, charge and discharge measurement and impedance measurement at the initial 1 c rate were performed, and the resistance was calculated. The measurement conditions are as follows. Initial capacitance measurement (25 ° C) Charging: CCCV 3.0 mA (lC), 2·8 V-2 hours (*) Discharge: CC 3·0 mA (lC), 0.01 ν (**) (*) cccv: constant Constant current voltage, (**)cc: Constant current impedance measurement (25°c) Measurement status: End of discharge measurement frequency: 20000 Hz~0.1 Hz Amplitude (ΔΕ): 10 mV 2) Low temperature characteristics as -30 °C The low-temperature characteristics were measured by charge and discharge at 1C rate and impedance measurement, and the electric resistance was calculated. The measurement conditions are as follows. Capacitance measurement (-30 ° C) Charging: CCCV 3.0 mA (lC), 2.8 V-2 hours (*) Discharge: CC 3.0 mA (lC), 〇.〇1 v(**) (*) CCCV: Constant current Constant voltage, (**) cc: Constant current impedance measurement (-30 °c) Measurement state: End of discharge measurement frequency: 20000 Hz to 0.1 Hz Amplitude (ΔΕ): 10 mV These results are shown in Table 2. 127610.doc -15- 200838015

As can be seen from Table 2, it was confirmed that the capacitor according to the embodiment of the present invention

The electric resistance was lower than that of the capacitor of Comparative Example 1, and the result was good, and it was able to function as a capacitor. The reason is that it is due to 35〇. (: The granulation is caused by the heating at the temperature, the shrinkage stress is generated between the powder electrode materials due to the shrinkage of the binder, and the portion covering the surface of the powder electrode material is reduced by the shrinkage, whereby the 'powder electrode The contact area between the materials is increased. [Simplified illustration of the drawing] Fig. 1 is a coating film of a collector electrode coated with a powder electrode material, an aromatic polyamine and a solvent before heating (activated carbon/aromatic polymerization)醯amine = 90 Wt% / 10 wt%) Microscopic photo of the surface (magnification: 35 〇〇). Figure 2 is a micrograph of the surface of the coating film shown in Figure 1 after heating (35 〇. Fig. 3 is a coating film of a collector coated with a powder electrode material, a mixture of an aromatic polyamine and a solvent before heating (activated carbon/aromatic polyamide = 7 〇 Wt% / 3 〇 Wt) %) Microscopic photograph of the surface (magnification: 3500). 127610.doc -16 - 200838015 Fig. 4 is a photomicrograph (magnification of 3500) of the surface of the coating film after heating (35 0 ° C) of the collector shown in Fig. 1. .doc -17-

Claims (1)

200838015 X. Patent application scope: 1. A binder for an electrode for an electric storage device, which comprises an aromatic polyamine which is granulated by heat treatment. 2. An electrode sheet produced by mixing a powder electrode material, a binder, and a solvent to prepare a slurry, and coating the slurry on a collector, wherein the binder is an aromatic polyamine. Further, the electrode sheet is obtained by heat treatment after coating. 3. The electrode sheet of claim 2, wherein the slurry contains 3 to 15% by weight of the aromatic polyamine based on the total amount of the aromatic polyamide and the powder electrode material. 4. The adhesive of claim 1 or the electrode sheet of claim 2, wherein the heating treatment is carried out at a temperature close to the crystallization temperature of the aromatic polyamide. 5. The adhesive of claim 1 or the electrode sheet of claim 2, wherein the aromatic polyamine is poly(p-lyisophthalamide). 6. The adhesive of claim 5 or the electrode sheet of claim 5, wherein the heating is performed at a temperature ranging from 33 〇 to 365 Torr. ',, and 7. The adhesive of claim 1 or the electrode sheet of claim 2, wherein the heat treatment is performed by heat between a pair of flat plates or a metal roll, Γ 8. An electrode sheet of 2, wherein the solvent is n, n-dimethylacetamide, N. decyl I pyrrolidone (NMP) or a mixture thereof. 9. An electric storage device using the electrode sheet of claim 2. 10. A capacitor using the electrode sheet of claim 2. 11 A battery using the electrode sheet of claim 2. 127610.doc 200838015 VII. Designated representative map: (1) The representative representative of the case is: figure (4). (2) A brief description of the symbol of the representative figure: (No description of the symbol of the component) 8. If there is a chemical formula in this case, please disclose the chemical formula that best shows the characteristics of the invention: (None) 127610.doc