JP2007214391A - Capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor which is capable of being reduced in internal resistance even if the capacitor is miniaturized. <P>SOLUTION: A positive case 1 and a negative case 4 facing each other are arranged nearly in parallel with each other. A separator 3 is arranged on the diagonal line of a rectangle formed between the positive case 1 and the negative case 4, a positive polarizable electrode 2a is arranged below the separator 3, and a negative polarizable electrode 2b is arranged above the separator 3. Peripheral edges of the positive case 1 and the negative case 4 are caulked through a packing 5 so as to enable the positive case 1 and the negative case 4 to serve as hermetically sealed housing vessels. The separator 3 is arranged aslant so that the part of the positive polarizable electrode 2a facing the negative polarizable electrode 2b can be increased in area, and the internal resistance of the capacitor can be reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a capacitor that includes a separator and a polarizable electrode and can reduce internal resistance.

  Capacitors such as electric double layer capacitors are used in mobile phones and household electric products as backup power sources and auxiliary power sources. The capacitor has a cylindrical shape so that the name of coin type or button type is used, and is soldered and mounted on printed boards of various electronic devices.

  FIG. 4 shows a conventional structure of a capacitor called a coin type or a button type. A positive polarizable electrode 32a, a separator 33, and a negative polarizable electrode 32b are stacked on a disc-shaped positive electrode case 31, and a disc-shaped negative electrode case 34 is covered from above, and a storage container sealed with a packing 35 is provided. Form. The positive electrode case 31 and the negative electrode case 34 serve as a positive electrode current collector and a negative electrode current collector, and terminals are separately attached to the positive electrode case 31 and the negative electrode case 34 and soldered to a printed circuit board or the like.

  On the other hand, a structure shown in FIG. 5 has been proposed as a miniaturized capacitor having a smaller mounting area than the coin-type or button-type capacitor shown in FIG. 4 (see, for example, Patent Document 1). A separator 43 is vertically installed at the center of the bottom surface of the concave container 41, and a positive polarizable electrode 42a and a negative polarizable electrode 42b are disposed with the separator 43 interposed therebetween.

A positive electrode current collector 44 is formed on the left bottom surface of the concave container 41 and is in contact with the positive polarizable electrode 42a, and a negative electrode current collector 45 is formed on the right bottom surface of the concave container 41 and is connected to the negative polarizable electrode 42b. Touching. The positive electrode current collector 44 is connected to the connection terminal 48, and the negative electrode current collector 45 is connected to the connection terminal 49. The concave container 41 is hermetically sealed by placing the seal ring 46 on the peripheral edge of the upper surface of the concave container 41 and further mounting and sealing the sealing plate 47 thereon.
JP 2000-294454 A JP 2001-216852 A

  However, the capacitor having the conventional structure has a problem that the internal resistance of the device is increased by downsizing. In the structure of FIG. 5, although the mounting area of the capacitor can be reduced and the size of the capacitor of FIG. 4 can be reduced, the size of the polarizable electrode and the separator can be reduced and the internal resistance can be reduced. It will increase further.

  As another structure in which the mounting area of the capacitor is reduced and the size is reduced, a current collector is formed on the bottom surface of the concave container, and a polarizable electrode, a separator, and the like are stacked on the current collector, and the opening of the concave container A structure in which a sealing plate is welded and hermetically sealed is shown in Patent Document 2, but if the size is reduced, the internal resistance increases for the same reason as described above, which causes a problem.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a capacitor that can reduce internal resistance even when the capacitor is miniaturized.

  In order to achieve the above object, the invention described in claim 1 uses a storage container having at least a pair of wall surfaces formed facing each other, and a pair of positive and negative polarizable electrodes and separators between the pair of wall surfaces. Is a capacitor in which the separator is disposed on a diagonal line between the pair of wall surfaces, and the pair of positive and negative polarizable electrodes are disposed so as to sandwich the separator.

  The invention according to claim 2 is the capacitor according to claim 1, wherein the storage container is constituted by a sealing lid and a concave container.

  According to a third aspect of the present invention, a pair of positive and negative current collectors are formed on the inner wall surface of the concave container, and the pair of polarizable electrodes are electrically connected to the pair of positive and negative current collectors. The capacitor according to claim 2, wherein the capacitor is connected.

  According to the present invention, a pair of positive and negative polarizable electrodes and separators are disposed and stored between the opposing wall surfaces of the storage container. Therefore, the area where the pair of positive and negative polarizable electrodes oppose each other can be widened, and the internal resistance can be reduced.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the structure of a first capacitor according to the present invention.

  The first capacitor is called a coin-type or button-type capacitor, and the entire storage container has a cylindrical shape. The disc-shaped positive electrode case 1 and the disc-shaped negative electrode case 4 constitute a storage container. The positive electrode case 1 and the negative electrode case 4 are separately provided with connection terminals and soldered to a printed circuit board or the like.

  The upper surface of the positive electrode case 1 and the bottom surface of the negative electrode case 4 correspond to the wall surfaces formed facing each other, and are arranged so as to be substantially parallel. Separator 3 is arranged on the diagonal line between the wall surfaces facing each other in positive electrode case 1 and negative electrode case 4, with positive polarizable electrode 2a on the lower side and a negative component on the upper side. A polar electrode 2b is provided. In order to obtain a storage container sealed with the positive electrode case 1 and the negative electrode case 4, the peripheral edge portions of the positive electrode case 1 and the negative electrode case 4 are caulked through a packing 5.

  Since the positive electrode case 1 and the negative electrode case 4 also serve as current collectors, they are made of metal. The packing 5 is an insulator, activated carbon or the like is used as the active material for the polarizable electrodes 2a and 2b, and glass fiber or the like is used for the separator 3.

  By arranging the separator 3 diagonally, the area of the separator can be made larger than that of the capacitor having the same type of conventional structure shown in FIG. 4, and the area of the positive and negative polarizable electrodes opposite to the separator can be made wider. And the internal resistance can be reduced. Further, when the area of the separator is increased, the amount of electrolyte contained in the separator is also increased, so that the internal resistance can be further reduced.

Example 1
In Example 1, a polarizable electrode was prepared and an electrolytic solution was prepared as follows to form a coin-type first capacitor shown in FIG. The polarizable electrode was formed into a sheet by mixing 10% by weight of acetylene black and 10% by weight of polytetrafluoroethylene (hereinafter referred to as PTFE) into activated carbon powder having a specific surface area of 2000 m ² / g. The sheet thus obtained was punched into a disk shape having a diameter of 2.2 mm and a thickness of 0.7 mm to produce two positive and negative polarizable electrodes.

Next, the prepared polarizable electrode is pushed into the mold, and one of the upper and lower surfaces of the disc-shaped polarizable electrode is inclined so that one end is thinner than the other end and the cross-sectional shape is triangular. Polarizable electrodes 2a and 2b were formed. As the electrolytic solution, propylene carbonate was used as a solvent, and (C ₂ H ₅ ) ₄ NBF ₄ as a solute was dissolved to a concentration of 1 mol / l to prepare an electrolytic solution.

  The first capacitor shown in FIG. 1 is manufactured by first interposing a glass fiber separator 3 between the two polarizable electrodes 2a and 2b produced as described above, and a positive electrode case 1 made of stainless steel. Store inside. The electrolyte solution prepared above is poured into the stainless steel positive electrode case 1 and vacuum impregnated at 40 kPa for 30 seconds, and the polarizable electrodes 2a, 2b and the separator 3 are sufficiently impregnated with the electrolyte solution. Next, the packing 5 is disposed on the peripheral edge of the positive electrode case 1 made of stainless steel, and the negative electrode case 4 made of stainless steel is covered, and these are sealed and integrated, and the diameter is 4.0 mm and the thickness is 1.4 mm. The first capacitor of the coin type was completed.

(Comparative Example 1)
For comparison with the first capacitor of Example 1, a coin-type capacitor having a conventional structure shown in FIG. 4 was formed as follows. The separator 33 and the polarizable electrodes 32a and 32b were formed in the same manner as in Example 1 except for the difference in size and shape. In Comparative Example 1, the polarizable electrode was used in a cylindrical shape, and the polarizable electrode 32a, the separator 33, and the polarizable electrode 32b were sequentially stacked from the bottom surface of the positive electrode case 31 so as to be substantially parallel to the bottom surface of the positive electrode case 31. .

  Next, the internal resistance values of the capacitors of Example 1 and Comparative Example 1 formed as described above were measured. The internal resistance value was measured with an ohm tester at an alternating current of 1 kHz between the positive and negative electrodes, and the results were as follows. The internal resistance of the capacitor of Example 1 was 47Ω, and the capacitor of Comparative Example 1 was 55Ω. As is clear from this result, the internal resistance was reduced by arranging the separator on the diagonal of the longitudinal section inside the storage container.

  FIG. 2 shows a second capacitor of the present invention. The storage container is composed of a concave container 11 and a sealing plate 17 as a sealing lid. Inside the concave container 11, a positive current collector 14, a positive polarizable electrode 12a, a separator 13, a negative polarizable electrode 12b, A negative electrode current collector 15 is disposed.

  Both side surfaces of the concave container 11 or the back surface of the sealing plate 17 and the bottom surface of the concave container 11 correspond to the wall surfaces formed facing each other, and are formed so as to be substantially parallel. For example, assuming that both side surfaces of the concave container 11 are wall surfaces formed facing each other, the separator 13 is disposed on a diagonal line between the wall surfaces, and the positive polarizable electrode 12a is disposed on the lower side with the separator 13 in between. On the upper side, a negative polarizable electrode 12b is provided. In order to make the concave container 11 a sealed storage container, the seal ring 16 is disposed on the peripheral edge of the concave container 11, and the sealing plate 17 is put on, and seam welding is performed for sealing.

  The positive electrode current collector 14 is integrally formed on the left inner wall of the concave container 11 and the negative electrode current collector 15 is integrally formed on the right inner wall by Au plating, sputtering, or the like. The positive electrode current collector 14 is formed so as to penetrate the left side surface of the concave container 11, and is connected to the positive connection terminal 18 at the penetrating outlet. The negative electrode current collector 15 is formed so as to penetrate the right side surface of the concave container 11 and is connected to the negative connection terminal 19 at the penetrating outlet.

  The connection terminals 18 and 19 are terminals when attached to a printed circuit board or the like, and are made of a W metallized layer, a Ni plated layer, an Au plated layer, or the like. The polarizable electrodes 12a and 12b are made of activated carbon electrodes, and the separator 13 is made of glass fiber or the like.

  The concave container 11 is configured to be a hermetically sealed container by welding the sealing plate 17 over the opening of the concave container 11. The concave container 11 is made of resin, glass, ceramics, ceramic glass, metal, or the like. Since these materials are excellent in heat resistance, a capacitor configured using these materials is excellent in reflow soldering performance and long-term storage. Since the sealing plate 17 should have a coefficient of thermal expansion close to that of the concave container 11, resin, glass, ceramics, ceramic glass, metal, or the like is used as described above. Note that the sealing plate 17 as a sealing lid of the concave container 11 may not have a plate shape, and may have another shape as long as the opening of the concave container 11 can be sealed.

  Also in the second capacitor of the present invention, by arranging the separator 13 on the diagonal of the longitudinal section inside the storage container, the separator area can be formed wider than the capacitor shown in FIG. The opposing positive and negative polarizable electrodes can be formed with a large area, and the internal resistance can be reduced.

(Example 2)
In Example 2, as described below, a polarizable electrode was prepared and an electrolytic solution was prepared, thereby forming a chip-type second capacitor as shown in FIG. First, 10 wt% acetylene black and 10 wt% PTFE were added to activated carbon powder having a specific surface area of 2000 m ² / g and kneaded to prepare a polarizable electrode having a 3.3 mm square and a thickness of 1.0 mm.

Next, this polarizable electrode was pushed into the mold, and either one of the upper surface or the lower surface of the polarizable electrode was inclined to produce triangular prism-shaped polarizable electrodes 12a and 12b. The electrolytic solution was prepared by using propylene carbonate as a solvent and dissolving (C ₂ H ₅ ) ₄ NBF ₄ as a solute so as to have a concentration of 1 mol / l.

  The second capacitor shown in FIG. 2 was manufactured as follows. First, the inner surface of the concave portion of the concave container 11 made of alumina having a side of 5 mm and a height of 1.5 mm is subjected to gold plating on tungsten, and a metal layer that becomes two current collectors 14 and 15 insulated from each other is formed. The connection terminals 18 and 19 are formed on the outer wall surface of the recess so that the current collector penetrates the recess wall surface and is electrically connected.

  Next, one polarizable electrode 12a out of the two polarizable electrodes produced as described above is placed in a concave container 11 provided with a seal ring 16 at the upper peripheral edge, and a glass fiber is formed thereon. After the separator 13 was disposed, the other polarizable electrode 12b was placed.

  Then, the electrolytic solution prepared as described above was poured into the concave container 11 and vacuum impregnated at 40 kPa for 30 seconds. Next, the sealing plate 17 was arrange | positioned on the concave container 11, and it welded by parallel seam welding, and completed the 2nd capacitor. At this time, the force by which the welded sealing plate 17 presses the polarizable electrodes 12a, 12b and the separator 13 is dispersed in the horizontal direction of the concave container 11, so that each current collector and each polarizable electrode and each polarizable electrode are dispersed. And sufficient pressure can be applied between the separators.

  FIG. 3 shows a third capacitor of the present invention. The parts different in shape from those in FIG. The difference from the configuration of FIG. 2 is the shape of the separator 21 and the shapes of the polarizable electrodes 20a and 20b. For the polarizable electrodes 20a and 20b, the surface of the polarizable electrode formed in the shape of a triangular prism is wavy and the separator 21 is a flat separator in FIG. 2 formed on the polarizable electrodes 20a and 20b. Corrugated to match the corrugated surface.

(Example 3)
The separator 21 is formed into a wave shape, the polarizable electrode is pushed into the mold, and the polarizable electrode 20a includes a long side of the triangular shape of the cross section of the polarizable electrode formed in a triangular prism shape, and the surface in contact with the separator 21 is waved. A third capacitor was produced in the same manner as in Example 2 except that 20b was produced. When the sealing plate 17 is welded, the force by which the sealing plate 17 presses the polarizable electrodes 20a, 20b and the separator 21 is dispersed in the horizontal direction of the concave container 11 as described above, whereby each current collector and each component are separated. Sufficient pressure can be applied between the polar electrodes and between each polarizable electrode and the separator.

(Comparative Example 2)
In order to compare with the second and third capacitors, a capacitor having the configuration of FIG. A polarizable electrode was produced as follows and an electrolyte solution was prepared. The polarizable electrodes 42a and 42b were prepared by adding 10% by weight of acetylene black and 10% by weight of PTFE to activated carbon powder having a specific surface area of 2000 m ² / g and kneading them to make the long side 3.3 mm × short side 1.5 mm × thickness 1.0 mm. The electrolytic solution was prepared by using propylene carbonate as a solvent and dissolving (C ₂ H ₅ ) ₄ NBF ₄ as a solute so as to have a concentration of 1 mol / l.

  The capacitor having the configuration shown in FIG. 5 was manufactured as follows. In advance, the inner wall of the bottom surface of the concave portion of the concave container 41 made of alumina having a side of 5 mm and a height of 1.5 mm is plated with tungsten to form a metal layer that becomes two current collectors 44 and 45 insulated from each other. Then, connection terminals 48 and 49 are formed to be electrically connected through the side wall.

  A seal ring 46 is provided on the peripheral edge of the upper end of the concave container 41, the two polarizable electrodes 42a and 42b prepared as described above are installed in the concave container 41, and a glass fiber separator 43 is installed therebetween. And housed. Next, the electrolytic solution prepared as described above was poured into the concave container 41 and vacuum impregnated at 40 kPa for 30 seconds.

  And the sealing board 47 was arrange | positioned to the concave container 41, and it contacted by parallel seam welding, and the capacitor of the comparative example 2 was comprised. In the capacitor structure of FIG. 5, even if the sealing plate 47 is welded and sealed, no pressure is applied in the stacking direction of the polarizable electrode 42a, the separator 43, and the polarizable electrode 42b.

  Next, the internal resistance values of the capacitors of Examples 2, 3 and Comparative Example 2 formed as described above were measured. The internal resistance value was measured with an ohm tester at an alternating current of 1 kHz between positive and negative electrodes. The result was as follows. The internal resistance of the capacitor of Example 2 was 54Ω, the internal resistance of the capacitor of Example 3 was 50Ω, and the internal resistance of the conventional structure capacitor of Comparative Example 2 was 78Ω. As can be seen from the results, in particular, in the capacitor of Example 3, the surface area can be further increased by corrugating the separator and the polarizable electrode opposite thereto, so that the effect of reducing internal resistance is great.

  As is clear from this result, by arranging the separator on the diagonal line between the opposing wall surfaces of the storage container, the area where the pair of positive and negative polarizable electrodes oppose each other can be increased, thereby reducing the internal resistance. . Furthermore, since sufficient pressure can be applied between the polarizable electrode and the separator, the internal resistance can be further reduced.

Further, since the second and third capacitors have a configuration in which a pair of positive and negative polarizable electrodes, a separator, and a current collector can be accommodated in a concave container, and there is no need to attach a polarizable electrode to the sealing plate. The workability when welding the plates is improved, and the production yield is improved.

It is a figure which shows the structural example of the 1st capacitor of this invention. It is a figure which shows the structural example of the 2nd capacitor of this invention. It is a figure which shows the structural example of the 3rd capacitor of this invention. It is a figure which shows the structural example of the conventional capacitor. It is a figure which shows the other structural example of the conventional capacitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positive electrode case 2a Polarization electrode 2b Polarization electrode 3 Separator 4 Negative electrode case 5 Packing

Claims (3)

In a capacitor in which a storage container having at least a pair of wall surfaces formed facing each other is used, and a pair of positive and negative polarizable electrodes and a separator are disposed and stored between the pair of wall surfaces,
A capacitor, wherein the separator is disposed on a diagonal line between the pair of wall surfaces, and the pair of positive and negative polarizable electrodes are disposed so as to sandwich the separator.   The capacitor according to claim 1, wherein the storage container includes a sealing lid and a concave container.   A pair of positive and negative current collectors is formed on an inner wall surface of the concave container, and the pair of polarizable electrodes are electrically connected to the pair of positive and negative current collectors. Item 3. The capacitor according to Item 2.

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