JPS6035509A - electric double layer capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electric double layer capacitor using activated carbon as a polarizable electrode.

(Conventional configurations and their problems) Electric double layer capacitors use activated carbon with a large specific surface area as polarizable electrodes, and there are two types of configurations that can be broadly classified as follows.

FIG. 1 is a block diagram of a conventional wound electric double layer capacitor. First, as shown in Figure 1(a), a paste 1 obtained by mixing activated carbon powder, PTFE powder, and other organic hybrids is supported on an aluminum net 2, and then wrapped around a separator 3. Then, after impregnating the electrolyte, it is held in an aluminum case 4 as shown in Figure 1 (bl), 5 and 6 are electrode lead wires, and 7 is a wound capacitor body. .

FIG. 2 is a block diagram of a conventional flat plate type electric double layer capacitor, which is shown in Japanese Patent Application Laid-Open No. 55-99714, in which metal electrodes 128. It consists of a separator 13 impregnated with an electrolytic solution, and is held in cases 15 and 16 via an insulating gasket 14, and has a flat plate shape.

Since the structure shown in FIG. 2 uses activated carbon cloth as the polarizable electrode, the polarizable electrode itself is strong and can be manufactured very easily.

Furthermore, since there is no need to use a binder as shown in FIG. 1, the surface area of activated carbon can be effectively utilized.

By the way, when such an activated carbon cloth is obtained by carbonizing and activating the cloth, the structure of the fibers of the cloth, that is, the weave of the fibers, has a large influence on the characteristics of the capacitor. Specifically, fabrics with a high rate of fiber penetration into the fabric will require activation gas (e.g. water vapor, CO2,
(HC, etc.) sufficiently penetrates into the fiber surface, making it difficult for them to come into contact with each other, making it difficult for activation to proceed on the surface as a whole. Therefore, in order to fully activate the entire surface, unless the activation temperature is extremely high or the activation time is lengthened,
The ratio of 1m area per unit weight cannot be obtained. However,
If the activation crystallinity is increased or the activation time is increased, the strength of the produced activated carbon cloth will be significantly weakened, and in extreme cases, it will become unusable.

FIG. 3 shows an example of an apparatus for activating raw material fiber cloth.

The raw material fiber cloth 21 accommodated in the furnace body 20 is
0, the temperature can be controlled by the control device 22, and the raw material 174 fiber cloth 21 is activated to carbonize by coming into contact with the activation gas supplied from the activation gas supply device 23 at high temperature. As shown in a), when the composition of the raw material fibers is such that the ratio of the fibers 24 exposed on the surface of the cloth 21 is small compared to the amount of fibers that have entered the inside of the cloth in the thickness direction, During activation, only the surface of the cloth is activated, and the inside of the cloth is difficult to activate. Therefore, even if the fiber weight per unit surface area (hereinafter referred to as basis weight) is the same, as shown in Fig. 4(b), a cloth with a smaller ratio of fibers 24 exposed on the surface of the cloth 210 will be less activated. It becomes difficult.

Figure 5 shows the relationship between the surface fiber ratio (^qα) and the specific surface area after activation for a phenolic fiber cloth with a basis weight of 200 g r/m as a raw fiber cloth (hereinafter referred to as raw cloth). The solid line indicates activation conditions of 800℃3.
0 minutes, the dashed line is for 800'02 hours.

Figure 6 shows the original warped surface fiber ratio and the fiber strength of activated cloth (activated carbon cloth) as a function of the surface fiber ratio.

As shown in these results, for fabrics with a high surface fiber ratio, activation proceeds smoothly and uniformly even with the same basis weight, and surface strength is maintained high.

Figure 7 shows the characteristics of the electric double layer capacitor obtained using the above-mentioned activated carbon cloth.The horizontal axis shows the surface fiber ratio, and the vertical axis shows the capacity (Farad).The larger the surface fiber ratio, the more output. The capacity also increases. However, the capacity is a single cell with an electrode of 5 mmφ.

(Object of the Invention) The present invention is intended to improve the poor device characteristics caused by the insufficiently activated activated carbon cloth as described above.
The object of the present invention is to provide an electric double layer capacitor using activated carbon cloth for polarizable electrodes, which has a smooth thickness and a large specific surface area even when the amount is 1.

(Structure of the Invention) The present invention uses an activated carbon cloth obtained by activating a woven cloth with a high surface fiber ratio as a polarizable electrode. Cloth is used for the polarization electrode, and the cloth is one of plain weave, twill weave, twill weave, satin weave, or a combination thereof.

(Description of Examples) The present invention requires a woven activated carbon cloth with a surface fiber ratio of 0.01 or more.

There are two methods for increasing the surface fiber ratio. The first method is to select the weaving method of the secondary fibers, and the second method is to select the primary fibers that make up the secondary fibers. The thickness of the secondary fibers used in the present invention ranges from 1st to 40th diameter, but by using secondary fibers with an unreasonable diameter and bundling them together to form secondary fibers, it is possible to The effective fiber surface area of becomes large.

FIG. 8 is a schematic diagram showing the weaving methods of various raw fabrics used in the present invention, (a) is plain weave, (b) is twill weave, and (C) is plain weave.
(d) is a satin weave, and (d) is a diagonal weave.These are the main types. In all of these weaving methods, it is possible to set the surface fiber ratio to 001 or more by controlling the thickness of the secondary fibers, weaving density, etc., and the strength of the resulting fabric is high, making it possible to It also becomes easier to handle.

Figure 9 shows the relationship between primary fibers, secondary fibers, and woven fabrics, and (a) shows a plain weave of secondary fibers 41 with a diameter of 0.5 mm, which are bundled primary fibers 40 with a diameter of 0.2 μm and a length of 100 mm. 9
The cloth 42 (b) has a diameter of 10 μm and a length of 100 mm.
A cloth 45 made of plain weave secondary fibers 44 with a diameter of 0.5 mm made by bundling primary fibers 43, (c) is a secondary fiber with a diameter of 0.5 mm.
The fabric 47 is made by weaving the spun yarn 46 of mm in length as it is.

When these three types of fabrics are activated under the same conditions 1., the activation gas contacts and reacts with more fiber surfaces in the order of (c) → (b) → (a).

Next, specific examples of the present invention will be shown.

(Example) Novolac fibers with a diameter of 04 μm and a length of 4100 mm are bundled to make secondary fibers of 100 μm, and two of these are used as warp and weft to plain weave to make a cloth with a surface fiber ratio of 05. This cloth is activated by keeping it in an atmosphere of 800° C. for 30 minutes using an activation gas such as water vapor or CO□. Subsequently, an aluminum electrode is formed on one side of this activation cloth by plasma spraying, and a circular shape with a diameter of 5 mm is punched out. A separator impregnated with an electrolytic solution consisting of propylene carbonate, γ-butyrolactone, and tetraethylammonium barchlorate is sandwiched between the two electrodes made in this way, and is covered with a metal cake with a gasket interposed between them to form a flat plate capacitor. form.

The table shows the characteristics of the electric double layer capacitor obtained according to the present invention. In the same figure, as a conventional example, a plain weave cloth using the same secondary fibers as the present invention is shown, and the surface fiber ratio is 0.05.
2 fabrics (surface fiber ratio -0, 1) using two 100 μm diameter spun yarns for the warp and weft (surface fiber ratio -0, 1), 02 fabrics were fabricated with an electric double layer by the same method as above. The characteristics when assembled into a capacitor are also listed.The fiber of the conventional example was also activated under the same conditions as the present invention.

Table (Effects of the Invention) As explained above, according to the present invention, the activation gas at the time of activation of the cloth comes into uniform and sufficient contact with the entire surface, so that the constituent fibers can be activated in a short time and effectively. proceed. The activated carbon cloth obtained by this method has a large effective surface area per unit area, and when used as a polarizable electrode of a capacitor, it can obtain capacitor characteristics of large capacity and low resistance. The present invention makes it possible to produce a small-sized, large-capacity flat plate type electric double layer capacitor, and since the specific surface area of the cloth can be used effectively, the usage cost is also reduced, and there is an advantage that the industrial value is extremely high.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional wound electric double layer capacitor.
Figure 2 is a configuration diagram of a conventional flat root type electric double layer capacitor.
Figure 3 shows an example of a device for activating raw fiber cloth, Figure 4 shows the surface fiber ratio of the cloth, and Figure 5 shows the relationship between the surface fiber ratio of the raw fabric and the specific surface area of the activation cloth. Figure 6 shows the relationship between the surface fiber ratio of the original fabric and the strength of the activation cloth, and Figure 7 shows the relationship between the surface fiber ratio of the original fabric and the electric double layer capacitor characteristics obtained using the activation fabric. FIG. 8 is a schematic diagram showing the weaving methods of various raw fabrics used in the present invention,
FIG. 9 is a diagram showing the relationship between primary fibers, secondary fibers, and woven fabric. ] ・・・・・・Paste, 2 ・・・・・・Aluminum net, 3.13・・・・・・Separator, 4・・・・・・・・・Aluminum case, 5, 6
・・・・・・・・・Electrode lead wire, 7・・・・・・・・・・・・
・Wound capacitor body, 11...Activated carbon fiber cloth, 12゛°゛...°metal electrode, 14...
・Insulating Gas Ken]・, 15・ ・Case, 20 ・
... Furnace body, 21 ... Raw material fiber cloth, 22.
...Control device, 23...Activation scum supply device, 24 ...Fiber, 40.43 ...
...-Next fiber, 41. ．． 44...--Secondary fiber, +
12.45.47... Cloth. Special RF applicant Matsushita Electric Industrial Co., Ltd. 1': 'L'l'l Agent Tsuneji Hoshino + [' Figure 1 (b) Figure 2 Figure 4) f 1 Figure 5 Figure 6: Surface fiber deposition Figure 7: Surface scarification Figure 8: Figure 9

Claims (1)

[Scope of Claims] (1) A polarizable electrode characterized by using an activated carbon fiber cloth with a weaving method having a surface fiber ratio (total geometric surface area of cloth/total geometric surface area of secondary fibers) of 0.01 or more. electric double layer capacitor. (2) The activated carbon fiber cloth is woven using any of the following weaving methods: plain weave, oblique weave, satin weave, or a combination of these weaving methods (claim 0) (3) The electric double layer capacitor according to claim (g), wherein the secondary fibers are twisted primary fibers having a thickness of 1011 m or less. a. The electric double layer capacitor according to claim (1), characterized in that the activated carbon fiber cloth is a novolac-based activated carbon fiber cloth obtained by carbonization activation of a phenolic fiber cloth. (5) Activated carbon The electric double layer according to claim 1, wherein the fiber cloth is obtained by carbonizing and activating a raw fiber cloth of a weaving method with a surface fiber ratio of 0.01 or more. Capacitor. (6) The electricity according to claim (5), wherein the carbonization activation is performed in an atmosphere of one or more of water vapor, carbon dioxide scum, and hydrocarbon gas. double layer capacitor.