JPH1126329A - Wound electrochemical element - Google Patents

Abstract

(57) [Problem] To provide a highly reliable wound electrochemical element having excellent sealing properties even when used in a high-temperature, high-humidity environment. SOLUTION: An element unit 1 constituted by winding a pair of electrodes and a separator and impregnated with an electrolytic solution.
1, a bottomed cylindrical metal case 13 containing the element unit 11, an elastic sealing body 14 for sealing the opening of the metal case 13, and the elastic sealing body 14 connected to the pair of electrodes. An anode-side metal lead wire 12a and a cathode-side metal lead wire 12b, which are drawn out to the outside; and at least the cathode-side metal lead wire 12a of the anode-side metal lead wire 12a and the cathode-side metal lead wire 12b.
b, an electrically insulating resin coating layer 15 is provided on the surface of the portion in contact with the elastic sealing body 14;
5 is made of a rubber-modified hydrocarbon resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wound electrochemical device used for various electronic devices.

[0002]

2. Description of the Related Art A conventional wound-type electric double-layer capacitor as this kind of wound-type electrochemical element has been configured as shown in FIG. That is, in FIG. 2, reference numeral 1 denotes an element unit. The element unit 1 is formed by winding a pair of electrodes and a separator, and the pair of electrodes has an anode-side metal lead 2a and a cathode-side metal lead. 2b
Are connected. After the element unit 1 is impregnated with an electrolytic solution, it is housed in a bottomed cylindrical metal case 3. Reference numeral 4 denotes an elastic sealing member which is attached to the opening of the metal case 3 and seals the opening of the metal case 3 so that the electrolytic solution inside does not evaporate. The elastic sealing member 4 has two through holes 4a and 4b. The anode-side metal lead wire 2a and the cathode-side metal lead wire 2b pass through the through holes 4a and 4b and are drawn out. Further, the opening of the metal case 3 is provided with an elastic sealing body 4 provided in the opening.
At the same time, sealing is performed by drawing the outer periphery of the opening of the metal case 3 inward.

Further, propylene carbonate is used as a main solvent as an electrolyte, a quaternary ammonium salt is generally used as an electrolyte, and butyl rubber, which is excellent in airtightness, is used as the elastic sealing member 4. As the vulcanization method, sulfur vulcanization, quinoid vulcanization, resin vulcanization, and peroxide vulcanization are used.

[0004]

However, in the structure of the above-mentioned conventional wound type electric double layer capacitor, two through holes 4a and 4b provided in the elastic sealing member 4 are connected to the anode-side metal lead wire 2a and the cathode, respectively. When the wound electric double-layer capacitor is used in a high-temperature, high-humidity environment, the two through holes 4a formed in the elastic sealing body 4 are formed because the side metal lead wire 2b is penetrated and pulled out to the outside. , 4b
The device had a problem of sealing properties with respect to the electrolytic solution impregnated in the element unit 1.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a highly reliable wound electrochemical element having excellent sealing properties even when used in a high-temperature, high-humidity environment. It is the purpose.

[0006]

In order to achieve the above object, a wound electrochemical device of the present invention comprises a device unit comprising a pair of electrodes and a separator wound and impregnated with an electrolyte. A metal case having a bottomed cylindrical shape containing the element unit, an elastic sealing body for sealing an opening of the metal case, and connected to the pair of electrodes and pulled out to the outside through the elastic sealing body. An anode-side metal lead and a cathode-side metal lead, and at least a surface of a portion of the anode-side metal lead and the cathode-side metal lead that comes into contact with the elastic sealing body in the cathode-side metal lead is electrically insulated. A resin coating layer of a property is provided, and this resin coating layer is composed of a rubber modified hydrocarbon resin,
According to this configuration, it is possible to obtain a highly reliable wound electrochemical element having excellent sealing properties even when used in a high-temperature, high-humidity environment.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 of the present invention has an element unit which is constructed by winding a pair of electrodes and a separator and is impregnated with an electrolyte, and which has a built-in element unit. A bottom cylindrical metal case, an elastic sealing body for sealing the opening of the metal case, an anode-side metal lead wire connected to the pair of electrodes and penetrating through the elastic sealing body and drawn out to the outside. A cathode-side metal lead wire, and an electrically insulating resin coating layer is provided on at least a surface of a portion of the anode-side metal lead wire and the cathode-side metal lead wire that comes into contact with the elastic sealing body in the cathode-side metal lead wire. And, this resin coating layer is made of a rubber-modified hydrocarbon resin, and according to this configuration, due to the presence of the resin coating layer, even when used in a high-temperature, high-humidity environment,
Since the failure of the sealing property for the electrolyte solution impregnated in the element unit is drastically reduced, the life of the element unit is prolonged,
Thereby, a highly reliable wound type electrochemical element can be obtained.

According to a second aspect of the present invention, the rubber-modified hydrocarbon resin is constituted by a mixed resin obtained by mixing three components of a styrene-butadiene rubber, an aliphatic saturated hydrocarbon and a methylstyrene resin. If the mixed resin is used, compared to the case where the styrene-butadiene rubber is used alone,
This has the effect of reducing water absorption and moisture permeability. The reason for this is that the bonds of the main chains of the rubber-modified hydrocarbon resin are constituted almost entirely by single bonds.

Next, a specific embodiment of the present invention and a comparative example will be described. (Embodiment) FIG. 1 is a cross-sectional view of a wound electric double layer capacitor as a wound electrochemical element according to one embodiment of the present invention. In FIG. This is an element unit of an electric double layer capacitor. This element unit 11 is formed by winding a pair of electrodes and a separator. The pair of electrodes is formed by applying an activated carbon powder, a cellulose binder and conductive carbon black dispersed in a water-soluble solvent to an etched aluminum foil, and forming an aluminum anode on the pair of electrodes. The side metal lead wire 12a and the cathode side metal lead wire 12b are connected by needle caulking. The separator is made of glass mixed paper in which glass fibers mainly composed of cellulose are dispersed.

Then, the element unit 11 is impregnated with a 0.65M concentration electrolytic solution comprising propylene carbonate as a solvent and tetraethylaluminum tetrafluoroborate as an electrolyte, and then forms a bottomed cylindrical metal case 13 made of aluminum. Is housed inside. At the opening of the metal case 13, an elastic sealing member 14 made of butyl rubber, which is a sealing material, is attached so as to prevent the internal electrolytic solution from evaporating, and through holes 14a, 14b provided in the elastic sealing member 14 are provided. Then, the anode-side metal lead wire 12a and the cathode-side metal lead wire 12b are penetrated to the outside. Further, the opening of the metal case 13 is sealed by drawing the outer periphery of the metal case 13 inward together with the elastic sealing member 14 provided in the opening to form a wound electric double layer capacitor. Is composed. The external dimensions of the wound electric double layer capacitor according to the embodiment of the present invention are 18 mm in diameter and 35 mm in height.

An electrically insulating resin coating layer 15 is provided on the entire surface of the cathode-side metal lead wire 12b in contact with the elastic sealing member 14. The resin coating layer 15 is made of a rubber-modified hydrocarbon resin. The resin is applied to the entire surface of the cathode-side metal lead wire 12b with a brush, and is cured by drying.

Note that the resin is a metal lead wire 12 on the cathode side.
Alternatively, the element unit 11 may be coated in advance on a single body, or the element unit 11 may be formed by winding a pair of electrodes and a separator, and then may be coated on the surface of the cathode-side metal lead wire 12b. The rubber-modified hydrocarbon resin is composed of a mixed resin obtained by mixing three components of a styrene-butadiene rubber, an aliphatic saturated hydrocarbon, and a methylstyrene resin.

Comparative Example A portion of the anode-side metal lead wire 2a and the cathode-side metal lead wire 2b in the wound-type electric double-layer capacitor shown in FIG. 2 that comes into contact with the elastic sealing body 4 in the cathode-side metal lead wire 2b. , A wound electric double-layer capacitor in which the electrically insulating resin coating layer 15 was not provided as in the embodiment of the present invention.

Table 1 shows 20 wound-type electric double-layer capacitors according to one embodiment of the present invention and 20 wound-type electric double-layer capacitors according to a comparative example. A comparison was made between the time when the sealing property of the wound type electric double layer capacitor failed and the electrical characteristics when a DC voltage of 2.5 V was applied to the multilayer capacitor in a high temperature atmosphere of 70 ° C. Things.

[0015]

[Table 1]

As is clear from Table 1, in the wound type electric double layer capacitor of the comparative example, a defect of the sealing property was observed after about 5000 hours.
After 0 hour, the change in the electrical characteristics of the internal resistance and the capacitance became larger than the initial value. However, the wound electric double-layer capacitor according to one embodiment of the present invention has a capacity of 5 times.
Even after 000 hours and 10,000 hours, there was no occurrence of a defect in the sealing property, and the change in the electrical characteristics of the internal resistance and the capacitance was smaller than that of the comparative example.

In the embodiment of the present invention, the elastic sealing member 14 in the cathode-side metal lead wire 12b is used.
An electrically insulating resin coating layer 1 on the entire surface in contact with
5, the case where the electrically insulating resin coating layer 15 is provided on the entire surface of the anode metal lead wire 12a and the cathode metal lead wire 12b in contact with the elastic sealing body 14 The same effect can be obtained in

Further, in the above-mentioned embodiment of the present invention, a description has been given of a case where the present invention is applied to a wound type electric double layer capacitor. However, the present invention is not limited to this. The present invention can be applied to a wound electrochemical device such as a wound battery.

[0019]

As described above, the wound electrochemical device of the present invention is constituted by winding a pair of electrodes and a separator, and is provided with an element unit impregnated with an electrolytic solution and a built-in element unit. A bottomed cylindrical metal case, an elastic sealing body sealing the opening of the metal case, and an anode-side metal lead wire connected to the pair of electrodes and penetrating through the elastic sealing body and drawn out to the outside. And a cathode-side metal lead wire, an electrically insulating resin coating layer on a surface of at least a portion of the anode-side metal lead wire and the cathode-side metal lead wire that contacts the elastic sealing body in the cathode-side metal lead wire. Provided, and this resin coating layer is made of a rubber-modified hydrocarbon resin. According to this configuration, the element unit can be used even in a high-temperature, high-humidity environment due to the presence of the resin coating layer. To Since the failure of the sealing against soaked electrolyte depleted, the life of the element unit also becomes longer, but this makes it possible to obtain a wound reliable Kaigata electrochemical device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a wound electric double layer capacitor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a conventional wound electric double-layer capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Element unit 12a Anode side metal lead wire 12b Cathode side metal lead wire 13 Metal case 14 Elastic sealing body 15 Resin coating layer

Claims (2)

[Claims] 1. An element unit configured by winding a pair of electrodes and a separator and impregnated with an electrolyte, a bottomed cylindrical metal case incorporating the element unit, and an opening of the metal case. An anode-side metal lead and a cathode-side metal lead, which are connected to the pair of electrodes and penetrated to the outside through the elastic seal, and which are connected to the pair of electrodes. An electrically insulating resin coating layer is provided on the surface of at least a portion of the wire and the cathode-side metal lead wire that comes into contact with the elastic sealing body in the cathode-side metal lead wire, and the resin coating layer is made of a rubber-modified hydrocarbon resin. The configured wound electrochemical device. 2. The rubber-modified hydrocarbon resin comprises a mixed resin obtained by mixing three components of a styrene-butadiene rubber, an aliphatic saturated hydrocarbon and a methylstyrene resin.
3. The wound electrochemical device according to item 1.