JP2014063788A - Electric double layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric double layer capacitor having a small ESL (Equivalent Series Inductance).SOLUTION: When a length along a first direction x of first and second opposite parts 11c, 12c is denoted by W and a distance along the first direction between a first lead-out part 11d and a second lead-out part 12d is denoted by P, P/W is less than 0.8.

Description

  The present invention relates to an electric double layer capacitor.

  Conventionally, capacitors have been widely used in various electronic devices such as mobile phones. As a capacitor, for example, an electric double-layer capacitor (EDLC) as described in Patent Document 1 is known. Unlike a secondary battery, an electric double layer capacitor does not involve a chemical reaction during charging and discharging, and thus has a merit of having a long product life, a merit of being able to charge and discharge in a short time with a large current, and the like. . Therefore, attempts have been made to apply the electric double layer capacitor to applications requiring a long product life or applications requiring a large current.

JP 2012-23219 A

  There is a desire to reduce the equivalent series inductance (ESL) of electric double layer capacitors.

  The main object of the present invention is to provide an electric double layer capacitor having a small ESL.

  The electric double layer capacitor according to the present invention includes a first electrode, a second electrode, an exterior body, and an electrolyte. The second electrode is opposed to the first electrode. The exterior body houses the first and second electrodes. The electrolyte is filled in the exterior body. The first electrode has a first facing portion and a linear first lead portion. The first facing portion faces the second electrode. The first facing portion has a rectangular shape having a side extending along the first direction and a side extending along the second direction. The 1st drawer | drawing-out part is extended along the 2nd direction from the one side edge part in the 2nd direction of a 1st opposing part. The second electrode has a second facing portion and a linear second lead portion. The second facing portion is opposed to the first facing portion. The second facing portion has a rectangular shape having a side extending along the first direction and a side extending along the second direction. The 2nd drawer | drawing-out part is extended along the 2nd direction from the one side edge part in the 2nd direction of a 2nd opposing part. When the length along the first direction of the first and second opposing portions is W and the distance along the first direction between the first lead portion and the second lead portion is P Furthermore, P / W is less than 0.8.

  In a specific aspect of the electric double layer capacitor according to the present invention, W is 20 mm or less.

  In another specific aspect of the electric double layer capacitor according to the present invention, P / W is less than 0.6.

  According to the present invention, an electric double layer capacitor having a small ESL can be provided.

1 is a schematic plan view of an electric double layer capacitor according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1. It is a typical perspective view of the 1st electrode and 2nd electrode in one embodiment of the present invention. It is a graph which shows the relationship between W and ESL in an experiment example. It is a graph which shows the relationship between P / W and ESL in case W is 20 mm.

  Hereinafter, an example of the preferable form which implemented this invention is demonstrated. However, the following embodiment is merely an example. The present invention is not limited to the following embodiments.

  Moreover, in each drawing referred in embodiment etc., the member which has a substantially the same function shall be referred with the same code | symbol. The drawings referred to in the embodiments and the like are schematically described. A ratio of dimensions of an object drawn in a drawing may be different from a ratio of dimensions of an actual object. The dimensional ratio of the object may be different between the drawings. The specific dimensional ratio of the object should be determined in consideration of the following description.

  FIG. 1 is a schematic plan view of the electric double layer capacitor according to the present embodiment. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. As shown in FIGS. 1 and 2, the electric double layer capacitor 1 includes a plurality of first electrodes 11, a plurality of second electrodes 12, a separator 13, and an exterior body 10.

  The first electrode 11 includes a collecting electrode 11a and a polarizable electrode 11b disposed on the collecting electrode 11a. Similarly, the second electrode 12 includes a collecting electrode 12a and a polarizable electrode 12b disposed on the collecting electrode 12a. The collector electrodes 11a and 12a can be made of, for example, an aluminum foil. Each of the polarizable electrodes 11b and 12b is made of a porous body. Each of the polarizable electrodes 11b and 12b preferably includes, for example, a carbon material, platinum, gold, or the like, and more preferably includes a carbon material. Activated carbon is mentioned as a carbon material used preferably. In addition, the thickness of the collector electrodes 11a and 12a can be about 5 micrometers-100 micrometers, for example. The thicknesses of the polarizable electrodes 11b and 12b can be set to about 5 μm to 50 μm, for example.

  As shown in FIGS. 1 and 3, the first electrode 11 includes a first facing portion 11c and a linear first lead portion 11d. The first facing portion 11c faces the second electrode 12 (specifically, a second facing portion 12c described later). The first opposing portion 11c is provided in a rectangular shape having a side extending along the x-axis direction and a side extending along the y-axis direction.

  The first lead portion 11d extends linearly along the y-axis direction from the y1-side end portion of the first opposing portion 11c in the y-axis direction. The first lead portion 11d is drawn to the outside of the exterior body 10.

  The second electrode 12 includes a second facing portion 12c and a linear second lead portion 12d. The second facing portion 12c is opposed to the first facing portion 11c. The second facing portion 12c is provided in a rectangular shape having sides extending along the x-axis direction and sides extending along the y-axis direction.

  The second lead portion 12d extends linearly along the y-axis direction from the y1-side end portion of the second facing portion 12c in the y-axis direction. The second lead portion 12d is drawn to the outside of the exterior body 10. The second lead portion 12d extends in parallel with the first lead portion 11d. The first lead portion 11d and the second lead portion 12d are provided at different positions in the x-axis direction. The first lead portion 11d and the second lead portion 12d do not overlap when viewed from the z-axis direction. The second lead portion 12d is arranged on the x2 side in the x-axis direction with respect to the first lead portion 11d.

  The plurality of first electrodes 11 and the plurality of second electrodes 12 are alternately provided so that the first electrodes 11 and the second electrodes 12 face each other. A separator 13 is provided between the adjacent first electrode 11 and second electrode 12. The separator 13 separates the first electrode 11 and the second electrode 12.

  The first electrode 11, the second electrode 12, and the separator 13 are accommodated in the exterior body 10. In the present embodiment, the exterior body 10 is constituted by a laminate of resin films.

The exterior body 10 is filled with an electrolyte. The electrolyte includes a cation, an anion, and a solvent. Examples of the cation preferably used include tetraethylammonium salt. Examples of the anion preferably used include tetrafluoroborate ion (BF ⁴⁻ ) and bistrifluoromethylsulfonylimide ((CF ₃ SO ₂ ) ₂ N ⁻ ). Examples of the solvent preferably used include non-aqueous solvents such as propylene carbonate, ethylene carbonate, diethyl carbonate, and dimethyl carbonate, and aqueous solvents such as water.

In the electric double layer capacitor 1,
W: length (mm) along the x-axis direction of the first and second facing portions 11c, 12c,
P: distance (mm) along the x-axis direction between the first lead portion 11d and the second lead portion 12d,
P / W <0.8. For this reason, the equivalent series inductance (ESL) can be reduced. Moreover, when P / W <0.8, ESL can be further reduced by decreasing W within a range of 20 mm or less.

  From the viewpoint of making ESL smaller, P / W ≦ 0.7 is preferable, and P / W ≦ 0.6 is more preferable. W ≦ 20 mm is preferable, W ≦ 15 mm is more preferable, and W ≦ 10 mm is further preferable.

(Experimental Examples 1-15)
Under the following conditions, an electric double layer capacitor having a configuration substantially similar to that of the electric double layer capacitor 1 according to the above embodiment was produced, and ESL was measured. The results are shown in Table 1 and FIGS.

In Table 1,
W: length (mm) along the x-axis direction of the first and second facing portions 11c, 12c,
P: distance (mm) along the x-axis direction between the first lead portion 11d and the second lead portion 12d,
L: length (mm) along the y-axis direction of the first and second facing portions 11c, 12c,
T: width (mm) along the x-axis direction of the first and second lead portions 11d and 12d,
M1: distance (mm) along the x-axis direction between the x1 side end of the first and second facing portions 11c and 12c and the x1 side end of the first lead portion 11d;
M2: distance (mm) along the x-axis direction between the x2 side end of the first and second facing portions 11c, 12c and the x2 side end of the second lead portion 12d,
It is.

  From the results shown in Table 1 and FIGS. 4 and 5, it can be seen that ESL can be reduced by reducing P / W to less than 0.8. Moreover, when P / W is 0.8 or more, it turns out that ESL does not become small even if W is made 20 mm or less. On the other hand, when P / W is less than 0.8, it can be seen that ESL can be further reduced by reducing W within a range of 20 mm or less.

DESCRIPTION OF SYMBOLS 1 ... Electric double layer capacitor 10 ... Exterior body 11 ... 1st electrode 12 ... 2nd electrode 11a, 12a ... Collector electrode 11b, 12b ... Polarizable electrode 11c ... 1st opposing part 11d ... 1st extraction part 12c ... 2nd opposing part 12d ... 2nd drawer | drawing-out part 13 ... Separator

Claims (3)

A first electrode;
A second electrode facing the first electrode;
An exterior housing the first and second electrodes;
An electrolyte filled in the exterior body;
With
The first electrode is
A rectangular first opposing portion facing the second electrode and having a side extending along the first direction and a side extending along the second direction;
A linear first lead portion extending along the second direction from one side end portion in the second direction of the first facing portion;
Have
The second electrode is
A rectangular second opposing portion that faces the first opposing portion and has a side extending along the first direction and a side extending along the second direction;
A linear second lead portion extending along the second direction from one side end portion in the second direction of the second facing portion;
Have
The length along the first direction of the first and second opposing portions is W, and the distance along the first direction between the first lead portion and the second lead portion An electric double layer capacitor in which P / W is less than 0.8, where P is P.   The electric double layer capacitor according to claim 1, wherein W is 20 mm or less.   The electric double layer capacitor according to claim 1 or 2, wherein the P / W is less than 0.6.

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