JPH02285620A - Electric double layer capacitor - Google Patents

Abstract

PURPOSE:To obtain the title electric double layer capacitor in which the characteristics such as heat-resisting property, equivalent series resistor and the like can be improved by a method wherein a separator containing fibers, having at least a bent part, is provided as a component. CONSTITUTION:In an electric double layer capacitor in which an element, formed by separating a polarizable electrode 2 using a separator 1, is housed and the case is airtightly sealed with a metal cover 4, a separator 1 containing fibers which are at least bent at a part is provided therein. For example, the separator 1 is mainly composed of glass fibers and ceramic fibers and it contains the fibers having a bent part thereon. Two kinds of the glass fibers and the ceramic fibers are used as a main composition, that is, one is the fibers of about 1 to 10mum in diameter and about 7 to 30mm in length, the other one is about 0.05 to 1mum in diameter and about 3 to 10mm in length, and at least a part of the fibers is bent. Also, non-alkali glass and alkali glass are used in the case of the glass fibers.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an electric double layer capacitor.

(Prior technology) Electric double layer capacitors are conventionally made by laminating polarizable electrodes on both sides of a separator impregnated with an electrolytic solution and a current collector laminated on the surface of the polarizable electrodes, which is then housed in a metal case and sealed. The structure is such that For example, electrolytic paper or polyolefin sheet glass fiber is used as the separator.

(Problems to be Solved by the Invention) However, electrolytic paper has a large wetting current, and polyolefin sheets have drawbacks such as poor electrolyte retention and low heat resistance.

In addition, fibers such as glass fibers and ceramic S fibers can improve these drawbacks, but because they are hard fibers, they have weak restoring force, and because the fibers are not physically connected to each other, they easily break and tear. There is. By the way, with use, the pressure inside the metal case increases and the electrolyte in the separator decreases, which reduces the adhesion between the polarizable electrode and the separator and creates a gap. Glass fibers and the like have a weak restoring force, resulting in a significant decrease in adhesion and an increase in equivalent series resistance (hereinafter referred to as ESR).

The purpose of the present invention is to improve the above-mentioned drawbacks and improve heat resistance and ESR.
The present invention provides an electric double layer capacitor that can improve characteristics such as:

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an electric double layer capacitor in which an element in which polarizable electrodes are separated by a separator is housed in a metal case and sealed with a metal lid. The present invention provides an electric double layer capacitor characterized by having a separator containing 4 as a component which is bent at a certain point.

The present invention also provides an electric double layer capacitor in which the main component of the separator in the above invention is glass fiber or ceramic 41i fiber.

(Function) Glass LLI fibers and ceramic S fibers themselves have high heat resistance. When some of these II fibers are bent into a dogleg shape, a spiral shape, or an arc shape, the restoring force is improved, the fibers are easily caught on each other, and are less likely to separate, thereby improving ESR.

(Example) Hereinafter, the present invention will be explained based on examples.

In FIG. 1, numeral 1 denotes a separator, which is mainly composed of glass A fibers or ceramic fibers, and includes #4 fibers bent at at least one location. Glass #4 fibers and ceramic fibers have a diameter of 1 to 10 μm and a length of 7 to 30 mm, and a diameter of 0.05 to 1 μm and a length of 0.3 to 1 μm.
There are two types, one with a size of about 0 mrn, and these are the main components. It is assumed that this #4#L is partially bent at at least one place. In addition, for glass Ili fibers, alkali-free glass (hereinafter referred to as E glass) or alkali glass (hereinafter referred to as C glass) is used;
O2An 203-B203-It refers to glass with little or no alkali content such as BaO, the latter being Na20
-cao-s i 02, 5102, Na20-B20
3-8 i02, K20-cao-s i02, etc. as the main components. And the ceramic fibers are All 203, ditanic acid, 13al iOs, Zr
O3,5iC1SiN4,Kq 5iO2AJ1203
It refers to something whose ingredients are Note that boric acid or borax may be added to some extent (within 30% as 820a). 2
are polarizable electrodes laminated on both sides of the separator 1, and are made of activated carbon, conductive carbon black, or the like. 3 is a button-shaped case made of aluminum or stainless steel, and houses an element consisting of a separator 1 and a polarizable electrode 2. Reference numeral 4 denotes a metal lid, which is attached to the case 3 through a sealing member 5 by caulking.

Next, the above examples and comparative examples were subjected to a high temperature storage deterioration test (temperature 70°C, applied voltage 2.8V, storage time 1000
Hr> and the change in ESR was measured. The electric double layer capacitor used for measurement has a rating of 2.8V2F and a diameter of 20φ.
, a button type with a thickness of 2 mtn.

The manufacturing conditions for the separators of Examples and Comparative Examples are as follows.

Example 1) E-glass S fiber (diameter 5 μ, length 5 rtrm %B2
30% (including 6% 0s) and 70% E glass 1liI (average diameter 0.5J1m, average length 2mm), and 20% of the former F glass was bent into a dogleg shape. The thickness of these fibers is 0.2s.
Shape into a sheet.

Example 2) 20% acrylonitrile m fiber (diameter 0.1μTrL) and E glass LLI fiber (diameter 5μ, length 6m#I, t3
20% (containing 6% zo3) and E glass (average diameter 0.5
μ, the average length is 2 m) and the thickness is Q.
, was formed into a 2 mm sheet and heated at a temperature of 200°C to decompose acrylonitrile.

Example 3) In Example 2), 20% of cellulose lli fibers (diameter 061 μm>) were used instead of acrylonitrile 1lilif.

Example 4) E glass (diameter 5 μm, length 6 mm, 2 pieces of B203)
>30% containing 0% and E glass (average diameter 0.5 μm,
The glass has an average length of 2111#I) 70%, and 20% of the former E glass is bent into a dogleg shape, and is in the form of a sheet with a thickness of 0.2 mm.

Example 5) E-glass (diameter 5 μm, length 6111#I, >30% containing 6% B2O3) and C glass (average diameter 0.5 μm1
A sheet with an average length of 2 s and 70% (including 5% CaO) and 20% of the previous E glass was bent into a dogleg shape, and a sheet with a thickness of 0°2 mm was made of these fibers. shall be as follows.

Example 6) In Example 1), spirally bent fibers were used.

Example 7) In Example 1), 80% of the latter F glass is bent into a substantially arc shape.

Example 8) S 102-Al120s l1lf fiber ((diameter 5 μ, length 6 m) 30%, E glass fiber (average diameter 0.5
μm1 average length 2Il1m) 70%, and 20% of the former fibers are bent into a dogleg shape.

Comparative Example In Example 1), the former E glass is not bent.

The measurement results are shown in the table.

Table As is clear from this table, according to the present invention, the change in FSR after being left unused can be doubled or less, but according to the comparative example, it is possible to reduce the change in FSR by 15 times or less.
It will be doubled.

In addition, from Example 1) and Example 4), it seems that the more 8203 in the F glass fiber, the better.

(Effects of the Invention) As described above, according to the present invention, the restoring force of the separator can be improved by using IIJII that is bent at at least one place, and the heat resistance can be improved by making the fibers made of glass or ceramic. Therefore, an electric double layer capacitor with excellent ESR characteristics can be obtained.

[Brief explanation of drawings]

The figure shows a front sectional view of an embodiment of the invention. 1...Separator, 2...Polarizable electrode, 3...
Case. Patent applicant Hitachi Capacitor Co., Ltd.

Claims (2)

[Claims] (1) An electric double layer capacitor in which an element in which polarizable electrodes are separated by a separator is housed in a metal case and sealed with a metal lid, characterized by having a separator containing as a component a fiber bent at at least one place. Electric double layer capacitor. (2) The electric double layer capacitor according to claim 1, wherein the separator is mainly composed of glass fiber or ceramic fiber.