JPH01310525A - Electric double-layer capacitor - Google Patents

Abstract

PURPOSE:To make it possible to obtain both excellent temperature characteristics and stable characteristics with time by a method wherein an element is constituted by interposing a separator and an electrolyte between polarized electrode, and a specific quantity of phosphorous acid is added to the electrolyte. CONSTITUTION:An element is constituted by interposing a separator and an electrolyte between the carbon electrodes 1 consisting of an activated fiber cloth, and phosphorous acid of 0.1-1.0wt.% is added to the electrolyte. By using this kind of electrolyte, the metal part, especially aluminum, in the capacitor element is stabilized by the phosphorous acid added to the electrolyte, and the dissolution and the current generated following the dissolution becomes low. As a result, stable characteristics can be maintained when initial characteristics and high temperature tests are conducted.

Description

[Detailed description of the invention] Industrial applications This research relates to electric double layer capacitors.

BACKGROUND OF THE INVENTION This type of conventional electric double layer capacitor has a so-called disc-shaped (coin-shaped, button-shaped) structure as shown in Fig. 1, and an electrolytic solution is placed between carbon electrodes 1 made of activated carbon fiber cloth. A metal case 3 and a metal lid 4 constitute an element with an impregnated separator 2 interposed therebetween, and serve as a current collector and an exterior material for the force/tsune element.
And it is sealed by a sealing body 5 such as a packing material which serves both as insulation and as a sealing material. Furthermore, in order to improve current collection and enable welding, an aluminum layer is formed by plasma spraying or the like on the surface that contacts the metal case 3 and the metal lid 4 for the electric conductor made of activated carbon fiber cloth. There is. Further, the surface of the sealing body 5 is normally coated with a thin layer of asphalt pitch to improve sealing performance.

Problems to be Solved by the Invention Such conventional electric double layer capacitors are often used to bank up semiconductor memories during power outages. Therefore,
Electric double layer capacitors must have sufficient reliability,
Good temperature characteristics and stable aging characteristics are essential.

By the way, the present inventors have already proposed that the degree of activation of the activated carbon fiber cloth used determines good temperature characteristics and stable aging characteristics. Furthermore, the aim is to provide unprecedented stable aging characteristics by improving the electrolyte.

Gamma-butyrolactone is used as the electrolyte for the electric double layer capacitor, especially when an anhydrous organic material is used.

Perchloric acid in propylene carbonate as a solvent.

Tetraalkylammonium fluorinated fluorinated acid and fluorinated phosphoric acid are used as solutes. This is because the electrolytic solution made of these has high conductivity and high decomposition voltage property, but this was insufficient to achieve the intended purpose.

The present invention is intended to solve these conventional problems.

Means for Solving the Problem The technical means is to construct an element by interposing a separator and an electrolyte between carbon electrodes made of activated carbon fiber cloth, and to add 0.0% phosphorous acid to the electrolyte. I W t% ~ 1.0 wt
% added.

Effect: When the electrolytic solution according to the present invention is used, the phosphorous acid added to the electrolytic solution stabilizes the metal parts, especially aluminum, in the capacitor element, thereby reducing dissolution and the accompanying dissolution current.

Example Hereinafter, one embodiment of the present invention will be described in detail.

First, activated carbon fiber cloth was used as a polarizable electrode.

An aluminum layer of about 0.051ffff is formed on one side of these by plasma irradiation. Its total thickness is 0.6n. The basis weight of activated carbon fiber cloth only is 1
Two pieces having a specific surface area of 26 g/m and a specific surface area of 1 ssom/l and a size of φ6 were prepared. As a casing member, a metal case with an outer diameter of φ11, a corresponding metal lid, and a sealing body were prepared. The metal lid with negative potential is made of 5US304, and the inner surface of the metal case with positive potential is made of aluminum, and the outer surface is made of 5US3.
In 2004, both were clad and integrated. The separator is a nonwoven fabric made of polypropylene fiber with a thickness of Q, 3
It is a porous sheet of 6 MM + basis weight so, 97 m. The sealing body is a polypropylene resin molded product. The electrolytic solution had a conventional basic composition of 1-1 mol of tetraethylammonium tetrafluoroborey in propylene carbonate, and six types of electrolytic solutions of the present invention were prepared by adding phosphorous acid as shown in the table. These are 3 per element.
0 μm was used. The sealing agent is applied to the inner surface of the sealing body and the inner surface of the metal case.

Next, the sealed single cell has a withstand voltage of 3V, but in order to cope with the driving voltage of a semiconductor memory, two cells were laminated to form a 5.5V product.

The product of the present invention and the conventional product were compared at 70'C, which is a high temperature load test conducted as a reliability test.

The electrical characteristics were determined after 3000 hours of application of 5.5V.

The table shows the amount of phosphorous added 'f! : Shows the initial characteristics of the electric double layer capacitor (measured temperature: 20'C) and the characteristics after a high temperature load test (70''C, rs, 5V applied) for 3000 hours.

As shown in the effect table of the invention, the product in which phosphorous acid is added to the electrolyte according to the present study can maintain stable characteristics in the initial characteristics and high temperature load test, and is Value is like a dog.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional electric double layer carrier bank. 1...Carbon electrode, 2...Separator, 3
...Metal case, 4...Metal lid, 5.
...Sealed body. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 figure

Claims (1)

[Claims] An electric diode characterized in that an element is constructed by interposing a separator and an electrolytic solution between carbon electrodes made of activated carbon fiber cloth, and 0.1 wt% to 1.0 wt% of phosphorous acid is added to the electrolytic solution. Multilayer capacitor.