JPH1064760A - Wound electrochemical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wound electrochemical element which is excellent in its sealing property and high in its reliability even when used in such an environmental conditions of high temperature and humidity. SOLUTION: The wound electrochemical element includes an element unit 11 having a pair of electrodes and a separator wound and also having a electrolytic solution impregnated therein, a bottomed cylindical metal casing 13 incorporating the element unit 11, an elastic sealing member 14 for sealing an opening of the metal casing 13, and metallic lead wires 12 and 12b as an anode and a cathode which are connected to the pair of electrodes and are passed through the resilient sealing member 14 as externally extended respectively. An electrically-insulating resin coated layer 15 is provided on a part of at least the cathode metal lead wire 12b of the lead wires 12a and 12b which is contacted with the resilient sealing member 14, and the resin material of the resin coat layer 15 is at least one of modified polyolefin resin, epoxy resin, polyester resin and fluoroplastic 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 of this type is configured as shown in FIG. That is, in FIG. 2, reference numeral 1 denotes an element unit.
Is formed by winding a pair of electrodes and a separator, and the pair of electrodes has an anode-side metal lead wire 2a.
And the cathode side metal lead wire 2b. 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 to seal the opening of the metal case 3 so as to prevent the internal electrolytic solution from evaporating. The elastic sealing member 4 has two through holes 4a and 4b. Established, and
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. The opening of the metal case 3 is sealed by drawing the outer periphery of the opening of the metal case 3 inward together with the elastic sealing member 4 provided in the opening.

Also, 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 provided with the anode side metal lead wire 2a and the cathode. 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 contacts the elastic sealing body in the cathode-side metal lead is provided. An insulating resin coating layer is provided, and the resin material of this resin coating layer is at least one of a modified polyolefin resin, an epoxy resin, a polyester resin, and a fluorine resin. According to this configuration, a highly reliable wound electrochemical element having excellent sealing properties even when used in a high-temperature, high-humidity environment can be obtained. Things.

[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, of the anode-side metal lead wire and the cathode-side metal lead wire, at least a surface of a portion of the cathode-side metal lead wire that comes into contact with the elastic sealing body, and an electrically insulating resin coating layer. And a resin material of the resin coating layer using at least one resin selected from a modified polyolefin resin, an epoxy resin, a polyester resin, and a fluorine resin. According to this configuration, due to the presence of the resin coating layer, even when the device unit is used in a high-temperature, high-humidity environment, the problem of the sealing property against the electrolyte solution impregnated in the device unit is drastically reduced. Thus, a highly reliable wound electrochemical element can be obtained.

Next, a specific embodiment of the present invention and a comparative example will be described. (Embodiment) FIG. 1 is a sectional view of a wound electric double layer capacitor according to an embodiment of the present invention. In FIG. 1, reference numeral 11 denotes an element unit of the wound electric double layer capacitor. The element unit 11 is configured 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 electrolytic solution containing propylene carbonate as a solvent and tetraethylammonium 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 Then, the anode-side metal lead wire 12a and the cathode-side metal lead wire 12b are penetrated to the outside. 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 m in height.
m.

Further, of the anode side metal lead wire 12a and the cathode side metal lead wire 12b, at least the entire surface of the cathode side metal lead wire 12b which comes into contact with the elastic sealing member 14 is coated with an electrically insulating resin coating. A layer 15 is provided, and a modified polypropylene, which is one type of modified polyolefin resin, is used as a resin material of the resin coating layer 15, and the modified polypropylene is applied by a brush,
Then, the hot air drying treatment is performed at a temperature of about 200 ° C. for 2 minutes or more. The modified polyolefin resin, which is the resin material of the electrically insulating resin coating layer 15, may be applied to the cathode-side metal lead wire 12b alone, or a pair of electrodes and a separator may be wound to form an element. Unit 1
After the structure 1 is formed, it may be applied to the surface of the cathode-side metal lead wire 12b.

Comparative Example A portion of the anode-side metal lead 2a and the cathode-side metal lead 2b in the wound-type electric double-layer capacitor shown in FIG. , 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 an embodiment of the present invention and 20 wound-type electric double-layer capacitors according to a comparative example. The results of comparing the time when the sealing property of the wound type electric double layer capacitor has a failure when applying a DC voltage of 2.5 V to the multilayer capacitor in a high temperature atmosphere of 70 ° C. and comparing the electrical characteristics are shown. Things.

[0013]

[Table 1]

As is apparent 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 changes in the internal resistance and the capacitance were larger than those at the initial stage. However, the wound electric double layer capacitor according to one embodiment of the present invention was changed after 5000 hours and 10,000 hours. Also, the number of failures in the sealability was extremely small, and the characteristic change was also small as compared with the comparative example.

In the above-described embodiment of the present invention, the resin material of the electrically insulating resin coating layer 15 is modified polypropylene, which is one type of modified polyolefin resin, but is not limited to this. The above-described embodiment is also applicable to the case where at least one resin selected from the group consisting of an epoxy resin, a polyester resin, and a fluorine resin, which are other resin materials of the electrically insulating resin coating layer 15, is used. The same operation and effect as described above can be obtained.

Further, in the above-mentioned embodiment of the present invention, a case where the present invention is applied to a wound type electric double layer capacitor has been described. However, the present invention is not limited to this. The present invention is also applicable to electrochemical devices such as wound batteries.

[0017]

As described above, the electrochemical device of the present invention has
An element unit configured by winding a pair of electrodes and a separator and impregnated with an electrolyte; a bottomed cylindrical metal case containing the element unit; and an elasticity for sealing an opening of the metal case. A sealing body, comprising: an anode-side metal lead and a cathode-side metal lead connected to the pair of electrodes and drawn out through the elastic sealing body; and the anode-side metal lead and the cathode-side metal Among the lead wires, an electrically insulating resin coating layer is provided on at least the surface of the cathode-side metal lead wire in contact with the elastic sealing member, and the resin material of the resin coating layer is a modified polyolefin resin, epoxy resin, or the like. A resin using at least one kind of resin among polyester resin, polyester resin, and fluorine resin. According to this configuration, the presence of the resin coating layer causes high temperature. Even when used in a high-humidity environment, the failure of the sealing property against the electrolyte solution impregnated in the element unit is drastically reduced, so that the life of the element unit is prolonged. What you can get.

[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 (1)

[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. Of the wire and the cathode-side metal lead wire, at least a surface of a portion of the cathode-side metal lead wire that comes into contact with the elastic sealing member is provided with an electrically insulating resin coating layer, and the resin material of the resin coating layer is modified. A wound electrochemical element using at least one resin selected from a polyolefin-based resin, an epoxy-based resin, a polyester-based resin, and a fluorine-based resin.