JP2002353072A - Coil-type electric double layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil-type electric double layer capacitor of such a structure that it can prevent the internal short circuit in a capacitor element, and can enhance the capacitor properties by improving the volume efficiency. SOLUTION: This coil type electric double layer capacitor prevents the damages to a separator due to the end face edge sections of the vane small plates of tab terminals 4 and 5, and also can prevent the internal short circuit of the capacitor element since this is constituted such that insulating sheets are stuck to the vane small plates of the tab terminal 4 for a positive electrode and the tab terminal 5 for a negative electrode joined to a collector foil for a positive electrode and a collector foil 2 for a negative electrode and insulation sheets 7, located between the vane small plates of the tab terminals 4 and 5 and the separators 6 as the fundamental constitution of the capacitor element. This is of such a constitution that the volume efficiency of the capacitor element rises and the capacitance is increased, because it is possible to use a thinner one than that in the past for the separator 6, since there is no risk of internal short circuit of the capacitor element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a charge / discharge mechanism mainly utilizing the adsorption and desorption of ions, and improves a capacitor characteristic of a capacitor element formed by winding a pair of positive and negative electrode bodies through a separator. The present invention relates to a wound electric double layer capacitor.

[0002]

2. Description of the Related Art Conventionally, this type of electric double layer capacitor has a charging capacity of about 1/60 of that of a nickel-cadmium secondary battery, but is different from a secondary battery which involves a chemical reaction at the time of charging and discharging. In principle, it is a charge / discharge mechanism that utilizes the adsorption and desorption of ions, so it can be charged in a short time with little deterioration due to charge / discharge, has a semi-permanent charge / discharge cycle, and has a wider operating temperature range than secondary batteries. That is the feature.

As such a conventional wound type electric double layer capacitor, for example, a structure as shown in a side sectional view of a main part (capacitor element) in FIG. 4 is exemplified. This wound type electric double layer capacitor is disclosed in
No. 17695 discloses a method in which activated carbon powder and an electrode material obtained by kneading a conductive material and a binder are applied to a positive electrode current collector foil 1 and a negative electrode current collector foil 2 each made of an aluminum etching foil. After the polarizable electrode layer 3 is provided, the positive electrode tab terminal 4 and the negative electrode tab terminal 5 made of aluminum are connected by caulking to the exposed surface where the polarizable electrode layer 3 is not provided, and then the current collector for the positive electrode is formed. By mounting lead terminals (not shown) on the foil 1 and the negative electrode current collector foil 2 respectively, a pair of positive and negative electrode bodies is produced, and further, the positive electrode current collector is sandwiched between the central portions of the separator 6 made of an insulating material. Electric foil 1. Each polarizable electrode layer 3 of the current collector foil 2 for the negative electrode
And a pair of positive and negative electrode bodies are spirally wound around the separator 6 such that the peripheral portion of the separator 6 is disposed on one exposed surface of the separator 6. We are making.

The capacitor element obtained here is usually housed in a metal case to complete a wound electric double layer capacitor.

[0005]

In the case of the above-mentioned wound type electric double layer capacitor, when a separator having a small thickness is used in the manufacturing process and the structure of the capacitor element, the tab terminals for the positive electrode and the negative electrode are caulked. Sometimes, the end portion (edge) of the swaged portion or the swaged portion may damage the separator, and in such a case, a short circuit between the positive and negative electrodes of the capacitor element (ie, an internal short circuit) often occurs. In addition, if the separator is made thick enough to withstand damage, the rate of occurrence of internal short circuits can be reduced, but there is a problem that the volumetric efficiency of the capacitor element is reduced and the capacitance is reduced.

That is, in the case of the conventional wound type electric double layer capacitor, the internal short circuit in the capacitor element is prevented and the volume efficiency is difficult to be improved. Therefore, it is difficult to improve the capacitor characteristics. Has become.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and the technical problems thereof are to prevent internal short circuit in a capacitor element and to improve the capacitor characteristics by improving the volumetric efficiency. It is an object of the present invention to provide a wound electric double layer capacitor having a structure to be obtained.

[0008]

According to the present invention, a pair of positive and negative electrode bodies each provided with a polarizable electrode layer on a current collector foil for a positive electrode and a negative electrode is wound via a separator. Terminal in which a wing plate portion is joined to a current collector foil for a positive electrode and a negative electrode and a wing plate portion of the tab terminal in a wound electric double-layer capacitor in which a capacitor element is accommodated in a metal case. Thus, a wound electric double-layer capacitor including the attached insulating sheet is obtained.

Further, according to the present invention, there is provided a capacitor element formed by winding a pair of positive and negative electrode bodies each having a polarizable electrode layer provided on a positive electrode current collector foil and a negative electrode current collector foil via a separator. In a wound type electric double layer capacitor housed in a metal case, affixed to the tab terminal where the wing plate is joined to the current collector foil for the positive electrode and the negative electrode, and to the part of the separator that comes into contact with the wing plate Winding type electric double-layer capacitor provided with the obtained insulating sheet.

Further, according to the present invention, there is provided a capacitor element formed by winding a pair of positive and negative electrode bodies each having a polarizable electrode layer provided on a positive electrode current collector foil and a negative electrode current collector foil via a separator. In a wound type electric double layer capacitor housed in a metal case, a tab terminal in which a wing plate portion is joined to a current collector foil for a positive electrode and a negative electrode, and a positive electrode in a separator,
A winding type electric double layer capacitor comprising an insulating sheet attached to a portion in contact with the polarizable electrode layer located on the back side of the negative electrode current collector foil is obtained.

In addition, according to the present invention, a capacitor element formed by winding a pair of positive and negative electrode bodies each having a polarizable electrode layer provided on a current collector foil for a positive electrode and a negative electrode, with a separator interposed therebetween. Terminal in which a wing plate portion is joined to current collector foils for the positive electrode and the negative electrode, and the wing plate portion of the tab terminal is attached to A first insulating sheet, a second insulating sheet attached to a portion of the separator that comes into contact with the wing plate portion, and a polarizable electrode positioned on the back side of the positive and negative electrode current collector foils in the separator. A wound electric double layer capacitor including at least one or more of the third insulating sheets attached to portions that come into contact with the layer is obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The winding type electric double layer capacitor according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side sectional view of a main part (capacitor element) showing a basic configuration of a wound electric double layer capacitor according to Embodiment 1 of the present invention. Also in the case of this wound type electric double layer capacitor, the basic components are the same as those of the conventional one shown in FIG. 4, and a positive electrode in which a polarizable electrode layer is provided on a current collector foil for a positive electrode and a negative electrode, respectively. A capacitor element formed by winding a pair of negative electrode bodies through a separator is accommodated in a metal case.

Referring to FIG. 1, an active carbon powder and an electrode material obtained by kneading a conductive material and a binder are applied to a current collector foil 1 for a positive electrode and a current collector foil 2 for a negative electrode, each of which is made of an aluminum etched foil. Then, after the polarizable electrode layer 3 is installed, the positive electrode tab terminal 4 and the negative electrode tab terminal 5 made of aluminum are connected by welding to the exposed surface where the polarizable electrode layer 3 is not installed, and then the positive electrode By mounting lead terminals (not shown) on the current collector foil 1 and the negative electrode current collector foil 2 respectively, a pair of positive and negative electrode bodies is produced, and furthermore, a center portion of the separator 6 made of an insulating material is sandwiched therebetween. Current collector foil for positive electrode Each polarizable electrode layer 3 of the current collector foil 2 for the negative electrode
And a pair of positive and negative electrode bodies are spirally wound around the separator 6 such that the peripheral portion of the separator 6 is disposed on one exposed surface of the separator 6. The point of manufacture is almost the same as the conventional one, but here, in addition, the positive electrode tab terminal 4 and the negative electrode tab terminal 5 joined to the positive electrode current collector foil 1, the negative electrode current collector foil 2
The insulating sheet 7 is stuck to the wing plate portion of the above.

Of these, a pair of positive and negative electrode bodies are:
The polarizable electrode layer 3 mainly composed of a carbon material is integrated with the current collector foil 1 for the positive electrode and the current collector foil 2 for the negative electrode. It is also possible to adopt a configuration in which the polarizable electrode layer 3 is provided on both surfaces of the foil 2. It is preferable to do so.

The separator 6 includes electrolytic paper, polyethylene non-woven fabric, polypropylene non-woven fabric, polyester non-woven fabric,
Kraft paper, Manila hemp sheet, glass fiber sheet and the like can be applied.

As the current collector foil 1 for the positive electrode and the current collector foil 2 for the negative electrode, a valve metal such as titanium or stainless steel can be generally applied in addition to an aluminum etching foil. This is preferable because it is excellent in electrochemical stability and lightweight. Note that the wing plate portions of the positive electrode tab terminal 4 and the negative electrode tab terminal 5 are joined to the positive electrode current collector foil 1 and the negative electrode current collector foil 2, And ultrasonic welding can be applied.

Here, the positive electrode tab terminal 4 and the negative electrode tab terminal 5 bonded to the positive electrode current collector foil 1, the negative electrode current collector foil 2, respectively.
As a material of the insulating sheet (tape) 7 attached to the wing plate portion of the above so as to cover the end surface edge portion, an electrolyte-resistant resin such as polyethylene, polypropylene, polyimide, or polyphenylene sulfide can be used, 50μ
m or less.

In the case of the wound type electric double layer capacitor having such a configuration, the wing plate portion of the positive electrode tab terminal 4 and the negative electrode tab terminal 5 and the separator 6
Since the insulating sheet 7 exists between the positive electrode tab terminal 4 and the negative electrode tab terminal 5, the separator 6 is prevented from being damaged by the edge of the end face of the wing plate portion, and the internal short circuit of the capacitor element is prevented. be able to. As described above, since the structure has no fear of the internal short circuit of the capacitor element, it is possible to use a thinner separator 6 than before, and the volume efficiency of the capacitor element is improved and the capacitance is increased. This is a configuration (a configuration in which capacitor characteristics are improved).

Hereinafter, a manufacturing process for manufacturing the wound type electric double layer capacitor according to the first embodiment will be specifically described.

First, a phenolic activated carbon having a specific surface area of 1500 m ² / g and carbon black were mixed at a weight ratio of 8: 1, and polyvinylidene fluoride dissolved in N-methylpyrrolidone as a binder was added to the mixed powder and kneaded. To make a slurry.

Next, a slurry was uniformly applied to a 25 μm thick aluminum foil as a current collector foil 1 for the positive electrode and a current collector foil 2 for the negative electrode, and dried. By rolling the current collector foil 2 to such an extent that the current collector foil 2 was not deformed, a pair of electrode bodies for a positive electrode and a negative electrode in which the polarizable electrode layer 3 was formed with a thickness of 70 μm was produced.

Furthermore, in the obtained pair of electrode bodies for the positive electrode and the negative electrode, the current collector foil for the positive electrode 1, the current collector foil for the negative electrode 2, the aluminum positive electrode tab terminal 4, and the negative electrode tab terminal 5 were formed. After connecting the wing plate portion by welding, on the current collector foil 1 for the positive electrode,
By mounting lead terminals (not shown) on the negative electrode current collector foil 2, a pair of positive and negative electrode bodies are prepared, and then a polyimide is placed on the wing plate portions of the positive electrode tab terminal 4 and the negative electrode tab terminal 5. An insulating sheet 7 made of a pressure-sensitive adhesive tape was applied.

Subsequently, a separator 6 having a thickness of 25 μm was arranged between a pair of electrode bodies for the positive electrode and the negative electrode, and was wound spirally until a predetermined diameter was obtained, thereby producing a wound capacitor element.

Finally, the winding type capacitor element is heated to 120 ° C.
, And then placed in a bottomed cylindrical metal case, and then an electrolyte prepared by dissolving tetraethylammonium tetrafluoroborate at a concentration of 0.7 mol / l in propylene carbonate is dropped, and the solution is passed through a gasket. Then, the wound electric double layer capacitor according to Example 1 was manufactured.

FIG. 2 is a side sectional view of a main part showing a basic structure of a wound type electric double layer capacitor according to a second embodiment of the present invention. Also in the case of this wound type electric double layer capacitor, the basic components are the same as those of the conventional one shown in FIG. 4, and a positive electrode in which a polarizable electrode layer is provided on a current collector foil for a positive electrode and a negative electrode, respectively. A capacitor element formed by winding a pair of negative electrode bodies through a separator is accommodated in a metal case.

Referring to FIG. 2, an active carbon powder and an electrode material obtained by kneading a conductive material and a binder are applied to a positive electrode current collector foil 1 and a negative electrode current collector foil 2 each made of an aluminum etching foil. Then, after the polarizable electrode layer 3 is installed, the positive electrode tab terminal 4 and the negative electrode tab terminal 5 made of aluminum are connected to the exposed surface where the polarizable electrode layer 3 is not installed by welding, respectively. By mounting lead terminals (not shown) on the current collector foil 1 and the negative electrode current collector foil 2 respectively, a pair of positive and negative electrode bodies is manufactured, and furthermore, a center portion of the separator 6 made of an insulating material is sandwiched therebetween. Current collector foil for positive electrode Each polarizable electrode layer 3 of the current collector foil 2 for the negative electrode
And a pair of positive and negative electrode bodies are spirally wound around the separator 6 such that the peripheral portion of the separator 6 is disposed on one exposed surface of the separator 6 so as to form a main part of the capacitor element. Although the point of manufacture is almost the same as the conventional one, here, in addition, the positive electrode tab terminal 4 and the negative electrode tab terminal 5 joined to the positive electrode current collector foil 1, the negative electrode current collector foil 2 in the separator 6. The insulating sheet 7 is adhered to a portion that comes into contact with the wing plate portion.

The respective parts here are also constructed in the same manner as in the first embodiment, and the manufacturing process for manufacturing the wound type electric double layer capacitor according to the second embodiment is also the same as that of the insulating sheet 7 made of polyimide adhesive tape. To the portion of the separator 6 that is in contact with the wing plate portion of the positive electrode tab terminal 4 and the negative electrode tab terminal 5 joined to the positive electrode current collector foil 1 and the negative electrode current collector foil 2. Except for the above, the same procedure as in Example 1 can be performed, and the wound type electric double layer capacitor according to Example 2 was manufactured by the above procedure.

FIG. 3 is a side sectional view of a main part showing a basic configuration of a wound type electric double layer capacitor according to Embodiment 3 of the present invention. Also in the case of this wound type electric double layer capacitor, the basic components are the same as those of the conventional one shown in FIG. 4, and a positive electrode in which a polarizable electrode layer is provided on a current collector foil for a positive electrode and a negative electrode, respectively. A capacitor element formed by winding a pair of negative electrode bodies through a separator is accommodated in a metal case.

Referring to FIG. 3, an active carbon powder and an electrode material obtained by kneading a conductive material and a binder are applied to a positive electrode current collector foil 1 and a negative electrode current collector foil 2 each made of an aluminum etching foil. After the polarizable electrode layer 3 is installed, the aluminum positive electrode tab terminal 4 and the negative electrode tab terminal 5 are connected by caulking to the exposed surface where the polarizable electrode layer 3 is not installed. By mounting lead terminals (not shown) on the current collector foil 1 and the negative electrode current collector foil 2 respectively, a pair of positive and negative electrode bodies is produced.
Further, the current collector foil 1 for the positive electrode sandwiches the central portion of the separator 6 made of an insulating material. The polarizable electrode layers 3 of the negative electrode current collector foil 2 are opposed to each other, and a separator 6 is provided on one exposed surface thereof.
Although a pair of electrode bodies of a positive electrode and a negative electrode are spirally wound around the separator 6 such that the peripheral portion of the capacitor element is disposed, a capacitor element as a main part is manufactured as in the related art.
In addition, an insulating sheet 7 is attached to a portion of the separator 6 that is in contact with the polarizable electrode layer 3 located on the back side of the positive electrode current collector foil 1 and the negative electrode current collector foil 2.

The respective parts here are also configured in the same manner as in the first embodiment. The manufacturing steps for manufacturing the wound type electric double layer capacitor according to the third embodiment are also the same as those for the positive electrode current collector foil 1, the negative electrode Current collector foil 2, positive electrode tab terminal 4, negative electrode tab terminal 5
And the insulating sheet 7 made of a polyimide adhesive tape is positioned on the back side of the positive electrode current collector foil 1 and the negative electrode current collector foil 2 in the separator 6. The winding type electric double-layer capacitor according to the third embodiment was manufactured in the same procedure as in the first embodiment, except that it was changed to be attached to a portion in contact with the polarizable electrode layer 3. .

Further, a wound type electric double layer capacitor according to a comparative example was manufactured in the same manner as in Example 1 except that the insulating sheet 7 made of an adhesive tape made of polyimide was not applied.

Therefore, the wound electric double layer capacitors according to Examples 1 to 3 and the wound electric double layer capacitor according to the comparative example, which were manufactured as described above, were each out of 100 pieces. The amount of defective products due to the short circuit and the average value of the capacitance and the internal resistance in the products excluding the defective products were examined.

As a result, the quantity of defective products in 100 products is 0 in Examples 1 to 3 and 31 in Comparative Example, and the capacitance (F) is in Example 1. 13.9, 13.8 in Example 2, 13.4 in Example 3, and 10.1 in Comparative Example, and the internal resistance (m
Ω) is 320 in the first embodiment and 3 in the second embodiment.
24, 327 in Example 3, and 450 in Comparative Example.

As a result, in the case of the wound type electric double layer capacitors according to the first to third embodiments, even if a separator having a smaller thickness than the conventional one is used, no defective product due to a short circuit is generated, and the capacitance is further reduced. And the internal resistance was also reduced, indicating that it had better characteristics than the wound electric double layer capacitor according to the comparative example.

In the wound type electric double layer capacitor according to each of the embodiments (Examples 1 to 3), as the insulating sheet 7 applied in the basic structure of the capacitor element, the positive electrode tab terminal 4 and the negative electrode First insulating sheet and separator 6 attached to wing plate portion of tab terminal 5
The second affixed to the portion that contacts the wing plate
And a third insulating sheet attached to a portion of the separator 6 that contacts the polarizable electrode layer 3 located on the back side of the positive electrode current collector foil 1 and the negative electrode current collector foil 2. However, the wound type electric double layer capacitor of the present invention is not limited to those disclosed in each of the embodiments, since at least one of these may be arbitrarily provided. . Incidentally, as a modified example related to the third insulating sheet, the insulating sheet is formed of a positive electrode current collector foil 1 and a negative electrode current collector foil 2 to which the positive electrode tab terminal 4 and the negative electrode tab terminal 5 of the separator 6 are joined. A configuration in which the electrode is attached to the polarizable electrode layer 3 on the back surface is also conceivable.

In any case, in the case of the wound type electric double layer capacitor of the present invention, as described above, the basic structure of the capacitor element is a structure having at least one of the first to third insulating sheets. If applied, the wing plate portions of the positive electrode tab terminal 4 and the negative electrode tab terminal 5 and the separator 6
In this configuration, the separator 6 is prevented from being damaged by the edge of the end face of the wing plate portion of the positive electrode tab terminal 4 and the negative electrode tab terminal 5, and an internal short circuit of the capacitor element is prevented. Can be prevented, and there is no fear of an internal short circuit. As a result, a thinner separator 6 can be used than in the prior art, and the volume efficiency of the capacitor element can be improved, and a configuration with an increased capacitance (a configuration with improved capacitor characteristics) can be obtained.

[0038]

As described above, according to the wound type electric double layer capacitor of the present invention, the basic structure of the capacitor element is that the terminal between the wing plate portion of the positive electrode tab terminal, the negative electrode tab terminal and the separator. In this configuration, the separator is prevented from being damaged by the edge of the end face of the wing plate portion of the positive electrode tab terminal and the negative electrode tab terminal, and the internal short circuit of the capacitor element can be prevented. Therefore, it is possible to use a separator that is thinner than before, thereby reducing the internal resistance, improving the volume efficiency of the capacitor element and increasing the capacitance (improving the capacitor characteristics). Configuration).

[Brief description of the drawings]

FIG. 1 is a side sectional view of a main part showing a basic configuration of a wound electric double layer capacitor according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of a main part showing a basic configuration of a wound electric double layer capacitor according to a second embodiment of the present invention.

FIG. 3 is a side sectional view of a main part showing a basic configuration of a wound electric double layer capacitor according to a third embodiment of the present invention.

FIG. 4 is a side sectional view of a main part showing a basic configuration of a conventional wound electric double layer capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Current collector foil for positive electrodes 2 Current collector foil for negative electrodes 3 Polarization electrode layer 4 Tab terminal for positive electrodes 5 Tab terminal for negative electrodes 6 Separator 7 Insulating sheet

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshitoshi Yokono 231 Sukazawa, Yamazaki-cho, Shiso-gun, Hyogo Prefecture Tokin Ceramics Co., Ltd.

Claims (4)

[Claims] 1. A metal case containing a capacitor element formed by winding a pair of positive and negative electrode bodies each having a polarizable electrode layer provided on a positive electrode current collector foil and a negative electrode current collector foil via a separator. In the circular electric double layer capacitor, a tab terminal in which a wing plate portion is joined to the current collector foil for the positive electrode and the negative electrode, and an insulating sheet attached to the wing plate portion in the tab terminal A wound electric double layer capacitor, comprising: 2. A winding in which a capacitor element formed by winding a pair of positive and negative electrode bodies each having a polarizable electrode layer provided on a positive electrode current collector foil and a negative electrode current collector foil via a separator is accommodated in a metal case. In the circular electric double layer capacitor, a tab terminal in which a wing plate portion is joined to the current collector foils for the positive electrode and the negative electrode, and an insulating member attached to a portion of the separator in contact with the wing plate portion. A wound type electric double layer capacitor comprising a sheet and a sheet. 3. A winding in which a capacitor element formed by winding a pair of positive and negative electrode bodies each provided with a polarizable electrode layer on a positive electrode current collector foil and a negative electrode current collector foil through a separator is accommodated in a metal case. In the circular electric double layer capacitor, a tab terminal in which a wing plate portion is joined to the positive and negative electrode current collector foils and a back surface of the positive and negative electrode current collector foils in the separator are provided. A winding type electric double layer capacitor, comprising: an insulating sheet attached to a portion which is in contact with the positioned polarizable electrode layer. 4. A winding in which a capacitor element formed by winding a pair of positive and negative electrode bodies each having a polarizable electrode layer provided on each of a positive electrode current collector foil and a negative electrode current collector foil via a separator is accommodated in a metal case. A tab terminal in which a wing plate portion is joined to the current collector foils for the positive electrode and the negative electrode, and a first insulating member attached to the wing plate portion of the tab terminal. A sheet, a second insulating sheet affixed to a portion of the separator in contact with the wing plate portion, and the polarizer positioned on the back side of the positive and negative electrode current collector foils in the separator. A winding type electric double layer capacitor comprising: at least one of a third insulating sheet attached to a portion in contact with an electrode layer.