JPH02167738A - Aluminum coated activated carbon fiber cloth - Google Patents

Abstract

PURPOSE:To reduce electric resistance not only in a surface direction but also in a thickness direction and to achieve uniformity and stability by forming an aluminum layer to the single surface or both surfaces of activated carbon fiber cloth and filling the gaps between fibers with aluminum and specifying the amount of aluminum at that time in a volumetric ratio. CONSTITUTION:The gaps of activated carbon fibers 2, 2 are filled with aluminum to form filled aluminum layers 1a, 1a. As a result, when the filled aluminum layers are looked on the side of the activated carbon fibers, the fibers 2, 2 show appearance like islands set in the filled aluminum layers 1a, 1a. The respective fibers 2, 2 are firmly bonded rigidly by the filled aluminum layers 1a, 1a and possibility such that the fibers are opened in a thickness direction is eliminated and an initial electric resistance value is lowered and possibility such that said value is varied with the elapse of time is eliminate. The pref. range of an aluminum amount is different according to the thickness of each fiber, the number of fibers, a weaving method and the kind of fiber cloth but preferably 10-70% in a volumetric ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an aluminum-coated activated carbon @ textile useful for use in capacitor electrodes, etc.

[Prior Art] In recent years, a new type of battery using porous carbon or the like as an electrode material has appeared and is attracting attention as a small battery such as an AA battery or a button battery. This type of battery has a very long shelf life of 5 years or more, and it is easy to maintain and manage.
The discharge curve is flat, and when used as a secondary battery, it can be charged relatively quickly, has a large number of charge/discharge cycles, and has a high #4 voltage, so it is useful for memory backup, etc. It is steadily increasing its share as a power source that requires long-term high reliability.

The specific M4 precept for the electrode material is a composite made of activated carbon fiber bundles that have a large actual surface area and a correspondingly large electric capacity, which are knitted or aggregated into a cloth shape, and one side of which is composited with aluminum that also serves as a current collector. It has been widely adopted.

The most common method for manufacturing such composite electrodes is the thermal spraying method, in which molten aluminum is sprayed onto one side of activated carbon fiber cloth using plasma spraying or the like, thereby integrating the two into a composite and forming an SN material. .

[Problems to be Solved by the Invention] When the above thermal spraying method is used, as shown in an enlarged cross-sectional view in FIG. 2. It will not penetrate into the gap in 2.

In the state shown in Figure 3, the electrical resistance in the plane direction of the fiber cloth is uniform and good, but the electrical resistance in the thickness direction varies depending on the degree of compression of the fiber cloth, and the resistance value It has been pointed out that the problem is that it is not stable.

Furthermore, it has been pointed out that there is a major problem in that the H2 gas generated at the cathode during use opens up the fibers, creating gaps and increasing the resistance value over time, which limits the usable time. .

An object of the present invention is to solve the problems of the prior art as described above, and to provide an aluminum-coated activated carbon fiber cloth that has low and uniformly stable electric resistance not only in the plane direction but also in the thickness direction.

[Means for Solving the Problem] The present invention forms an aluminum layer on one or both sides of an activated carbon fiber cloth, and fills the gap between the Al1 female with aluminum, and the amount of aluminum at that time is The volume ratio is 10 to 70%.

[Function] By filling the gaps between the stitches of the fiber cloth with aluminum, aluminum makes the fiber cloth rigid, stabilizes the size and shape, reduces the contact resistance between the 1IIi fibers, and lowers the initial electrical resistance. At the same time, the phenomenon that the resistance value in the thickness direction changes over time is also eliminated.

[Example] The present invention will be described below with reference to Examples.

FIG. 1 is an enlarged cross-sectional view of the aluminum-coated activated carbon fiber cloth according to the present invention, and FIG. 2 is an enlarged plan view of the same as seen from the activated side.

In the figure, ■ is composite aluminum, 2.2 is activated carbon fiber, and la and la are aluminum layers filled in the gaps between activated carbon fibers 2.2.

In the present invention, clearly different from the conventional example shown in FIG. 3, the gaps between each activated carbon fiber 2.2 are filled with aluminum to form filled aluminum layers 1a, la. As a result, when viewed from the activated carbon fibers al, the fibers 2.2 have an appearance like islands floating in the filled aluminum layers 1a, 1a, as shown in FIG. This filled aluminum layer 1a, l
Each of the m fibers 2, 2 is rigidly bonded by a, and this bond eliminates the risk that the fibers will become un<< in the thickness direction, which not only reduces the initial electrical resistance value but also causes it to fluctuate over time. That fear will also be resolved.

However, when viewed from the viewpoint of an electrode material, it is desirable that the amount of activated carbon be as large as possible in order to increase the electrical capacity. For this purpose, it is better to have a small amount of aluminum, but if it is too small, the filling aluminum layers 1a and 1a that connect these fibers in the gaps between the fibers 2.2 will not be formed sufficiently, and it will not be used as an electrode material. performance deteriorates.

The preferable range of the amount of aluminum is the thickness and number of m-fibers,
Although it varies depending on the type of fiber cloth such as the weaving method, it is suitable that the volume ratio is substantially in the range of 10 to 70%, more preferably in the range of 20 to 50%.

In order to obtain the aluminum-coated activated carbon cloth according to the present invention as described above, it is appropriate to use a hot press method, for example, by combining aluminum foil with a thickness of 0.1 to 0.5 mm and activated carbon cloth. Overlapping, preferably ±30 of the melting point of aluminum
It can be manufactured by applying a pressure of 20 to 200 kg/cs'' at a temperature of 0.degree. C. In this case, there is no problem in using aluminum powder instead of aluminum foil.

The appropriate fi temperature during pressurization as described above is ±30℃ of the melting point of aluminum.
This is because the deformation resistance of aluminum is large at temperatures below the melting point of 30°C, and it is difficult to fill the activated carbon 4aII fiber fabric with aluminum without destroying it. This is because if the temperature is raised above 0.degree. C., the activated carbon will not wet the molten aluminum, and the aluminum will be repelled, making it difficult to fill the fiber cloth.

Note that titanium, lithium, silicon, etc. can be used as composite metals as they have a high dissolution voltage in electrolyte, but aluminum is said to be superior in terms of workability and cost. be able to.

[Hatsurou Effect J] As described above, according to the aluminum-coated activated carbon fiber cloth according to the present invention, when it is used as an electrode material, it is possible to obtain stable discharge characteristics with a small initial resistance value, and also with a low resistance value. Since there is no change in discharge characteristics over time, stable characteristics can be maintained for a long period of time and high reliability can be established.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view of a fiber cloth according to the present invention, FIG. 2 is an enlarged flat view of the fiber cloth seen from its active side, and FIG. 3 is an enlarged cross-sectional view of a conventional example. 1 aluminum, 1a: filled aluminum layer, 2: activated carbon 1 fiber. Agent: Patent attorney Fujio Sato! Figure 1 Nialuminum 1a: Filled aluminum layer 2: I cracked charcoal repair

Claims (2)

[Claims] (1) An aluminum coating formed by forming an aluminum layer on one or both sides of an activated carbon fiber cloth made by knitting or aggregating fibrous activated carbon into a cloth, and filling the gaps between the fibers with the aluminum. Activated carbon fiber cloth. (2) The aluminum-coated activated carbon fiber cloth according to claim 1, wherein the amount of aluminum is 10 to 70% by volume.