JP2007208222A - Capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor attaining space saving and stability of internal resistance at the same time, without affecting the adhesion between polarizable electrodes as well as adhesion between a polarizable electrode and a collector even if sealing plate of a concave vessel deforms. <P>SOLUTION: In such state as an opening of a concave vessel 1 is laid sideways, with one of the facing sides of the concave vessel 1 faced down, a positive polarizable electrode 3a, a separator 4, a negative polarizable electrode 3b are stored and stacked along the side surface of the concave vessel 1. On the inside wall of the concave vessel 1, a negative collector 5 is formed on the upper side-surface while a positive collector 2 is formed on the lower side-surface. The positive collector 2 penetrates the bottom surface of the concave vessel 1, to be connected to a positive electrode connection terminal 8. The concave vessel 1 is sealed by welding a metal frame 6 to a sealing plate 7. A part of the sealing plate 7 constitutes a negative electrode connection terminal 7a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a capacitor in which a storage container includes a sealing lid and a concave container.

  Capacitors such as electric double layer capacitors are used in mobile phones and household electric products as backup power sources and auxiliary power sources. Conventional capacitors are soldered and mounted on printed circuit boards of various electronic devices. The capacitor has a cylindrical shape so that a coin type or a button type may be used. To solder this to a printed circuit board, it is necessary to attach a terminal separately. In addition, the mounting area is larger than the capacitor container due to the round shape.

  Therefore, in Patent Document 1, a concave container that houses a pair of positive and negative polarizable electrodes, an electrolyte, and the like is configured by a concave container and a sealing plate, and a current collector inside the concave container is used as an outer bottom surface portion or an outer side surface portion of the concave container. A connection terminal is disclosed which is electrically connected to the connection terminal located at the position where the connection terminal is integrated with the concave container.

  An example of this conventional structure is shown in FIG. A positive electrode current collector 22 made of a metal layer is formed on the entire inner bottom surface of the concave container 21, and the positive electrode current collector 22 penetrates the wall surface of the concave container 21 and is electrically connected to the positive electrode connection terminal 28 from the outer side surface of the concave container 21. Connected. A negative electrode connection terminal 29 is formed from the outer wall of the left side surface of the concave container 21 to the bottom surface, and is electrically connected to the negative electrode current collector 25 formed on the back surface of the sealing plate 27 via the metal frame 26 and the sealing plate 27. .

4 is manufactured, the positive polarizable electrode 23a, the separator 24, and the negative polarizable electrode 23b are sequentially stacked on the upper surface of the positive electrode current collector 22 formed in advance on the inner bottom surface of the concave container 21. Then, the metal frame 26 is placed on the edge of the upper surface of the concave container 21, and the sealing plate 27 is further placed thereon and welded to seal the concave container 21.
JP 2001-216852 A

  However, in the above-described conventional structure, the connecting terminal attaching step can be omitted and the mounting area can be reduced, but the sealing plate is deformed due to a temperature change when the capacitor is soldered to the printed circuit board of various electronic devices. However, this deformation gives a biased pressure to the laminated body arranged under the sealing plate, and the same deformation occurs in the laminated body. In this way, the deformation of the sealing plate is transmitted to the laminated body, and the adhesion between the pair of positive and negative polarizable electrodes for accumulating charges and the adhesion between the polarizable electrode and the current collector are lowered. There was a problem of increasing.

  The present invention was devised to solve the above-described problems, and even when deformation occurs in the sealing plate of the concave container, the adhesion between the polarizable electrodes and the adhesion between the polarizable electrodes and the current collector It is an object of the present invention to provide a capacitor that achieves both space saving and stabilization of internal resistance without affecting performance.

  In order to achieve the above object, the invention described in claim 1 uses a storage container composed of a concave container and a sealing lid, and a pair of positive and negative polarizable electrodes and separators between opposing side surfaces of the concave container. Is a capacitor housed and laminated along the side surface.

  The invention described in claim 2 is characterized in that a current collector is formed on at least the side wall of the concave container, and the current collector and the polarizable electrode are electrically connected. It is a capacitor of description.

  The invention according to claim 3 is the capacitor according to claim 2, wherein the current collector is extended to the inner wall of the bottom surface of the concave container.

  The invention according to claim 4 is characterized in that the sealing lid is electrically insulated from the pair of positive and negative polarizable electrodes. Capacitor.

  Moreover, invention of Claim 5 is that the area of the said sealing lid is smaller than one area of the side wall which the concave container opposes, It is any one of Claims 1-4 characterized by the above-mentioned. Capacitor.

  According to the present invention, a pair of positive and negative polarizable electrodes, a separator, and a current collector are housed and stacked along the side surface of the concave container between the opposing side surfaces of the concave container, and the current collector is collected on the side wall of the concave container. Since the polarizable electrode is electrically connected to the current collector by forming a body, even if the sealing lid is deformed, the adhesion of the polarizable electrode and the current collector is not affected. Further, a space can be secured between the cell and the sealing lid, and further, the deformation of the sealing lid can be prevented from being transmitted, so that an increase in internal resistance can be prevented.

  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.

  In a state where the opening of the concave container 1 is set sideways, that is, between the opposing side surfaces A and B with one of the opposing side surfaces A and B of the concave container 1 facing down (the side surface B in FIG. 1). In addition, the positive electrode current collector 2, the positive polarizable electrode 3a, the separator 4, the negative polarizable electrode 3b, and the negative electrode current collector 5 are accommodated and stacked along the side surfaces A and B. The positive electrode current collector 2, the positive polarizable electrode 3 a, the separator 4, the negative polarizable electrode 3 b, and the negative electrode current collector 5 have a square and flat plate shape, and these constitute one cell. . The side surfaces A and B of the concave container 1 are formed substantially in parallel, and the main surfaces of the positive electrode current collector 2, polarizable electrode 3 a, separator 4, polarizable electrode 3 b, and negative electrode current collector 5 are formed on the side surfaces. It is installed so as to face each other, and each main surface is also arranged substantially in parallel.

  A negative electrode current collector 5 is integrally formed on the inner wall of the side surface A of the concave container 1, and a positive electrode current collector 2 is integrally formed on the inner wall of the side surface B by Au plating, sputtering, or the like. The positive electrode current collector 2 is formed so as to penetrate the bottom surface of the concave container 1, and is connected to the positive electrode connection terminal 8 at an outlet that penetrates. Moreover, in order to improve adhesiveness and reduce internal resistance, a conductive adhesive is used between the positive electrode current collector 2 and the polarizable electrode 3a and between the negative electrode current collector 5 and the polarizable electrode 3b. You may make it join.

  The positive electrode connection terminal 8 is made of a W metallized layer, a Ni plated layer, an Au plated layer, or the like. The polarizable electrodes 3a and 3b are made of activated carbon electrodes, and the separator 4 is made of glass fiber or the like.

  The concave container 1 is made of ceramic such as alumina or zirconia, and is configured to be a sealed container by covering a metal sealing plate 7 on the opening of the concave container 1 and welding. In addition, the sealing plate 7 as a sealing lid of the concave container 1 may not have a plate shape, and may have another shape as long as the opening of the concave container 1 can be sealed. Since it is comprised as mentioned above, as shown in FIG. 1, space is ensured between the cell and the sealing board 7, and it becomes a structure which is not closely_contact | adhering.

  As in the conventional structure of FIG. 4, a cell in which a pair of positive and negative polarizable electrodes, separators, and current collectors are stacked is stored between the bottom surface of the concave container and the sealing plate, and the sealing plate and the concave container are compressed. In the present invention, as shown in FIG. 1, a pair of positive and negative polarizable electrodes, a separator, and a current collector are placed between the opposing side surfaces of the concave container. Since the layers are laminated so as to face the side surfaces and are not in close contact with the sealing plate, the deformation of the sealing plate is not transmitted to the cell.

The first capacitor having the structure of FIG. 1 was manufactured as follows. The polarizable electrodes 3a and 3b are prepared by adding 5 wt% of acetylene black and 5 wt% of PTFE (polytetrafluoroethylene) to activated carbon powder having a specific surface area of 2000 m ² / g and kneading them. Electrode. The electrolytic solution was prepared by using propylene carbonate as a solvent and dissolving (C ₂ H ₅ ) ₄ NBF ₄ (tetraethyl ammonium tetrafluoroboron) as a solute to a concentration of 1 mol / l.

  Next, although it was the manufacturing method (assembly method) of the 1st capacitor, it carried out as follows. First, as the concave container 1, for example, an alumina one having a square shape with an outer dimension of each wall surface of about 5 mm on a side was used. The positive electrode assembly formed by plating the polarizable electrodes 3a and 3b as described above with the separator 4 made of cellulose interposed between the two polarizable electrodes 3a and 3b produced as described above. The electric body 2 and the negative electrode current collector 5 were housed in the concave container 1 provided in advance from the lateral opening.

  After injecting the same amount of the above-described electrolyte as the polarizable electrode volume so that the polarizable electrodes 3a and 3b are sufficiently immersed in the concave container 1, the metal made by brazing the open end of the concave container 1 in advance is used. The metal frame body 6 and the sealing plate 7 were sealed by welding to complete the capacitor shown in FIG. Here, the negative electrode current collector 5 is electrically connected to the metal frame 6 and the sealing plate 7, and a part of the sealing plate 7 constitutes a negative electrode connection terminal 7 a that is soldered to the substrate. The positive electrode current collector 2 is electrically connected to a positive electrode connection terminal 8 that is soldered to the substrate.

  Next, a second capacitor according to the present invention is shown in FIG. The parts different from those in FIG. 1 are indicated by different reference numerals. In the first capacitor, the sealing plate 7 is electrically connected to the negative electrode current collector 5 via the metal frame 6, but in the second capacitor, the sealing plate 11 and the negative electrode current collector 5 are electrically connected. The negative electrode current collector 5 is not connected and is formed so as to penetrate the bottom surface of the concave container 1 and is electrically connected to the negative electrode connection terminal 10 at the penetrating outlet. The negative electrode connection terminal 10 is made of a W metallized layer, a Ni plated layer, an Au plated layer, or the like.

  Therefore, it is not necessary to use a part of the sealing plate 7 as the negative electrode connection terminal 7a as shown in FIG. 1, and the sealing plate 11 of FIG. 2 has a different shape and has a smaller area than the sealing plate 7 of FIG. Can do. In addition, the positive electrode connection terminal 9 is formed at a position different from that shown in FIG. 1, and the positive electrode current collector 2 is formed so as to penetrate the lower side surface of the concave container 1. Connected to.

  In the second capacitor, the production of the polarizable electrode and the preparation of the electrolytic solution were performed in the same manner as in the first capacitor. A positive electrode current collector 2 formed by plating, with a cellulose separator 4 interposed between two polarizable electrodes 3a and 3b produced in the same manner as the first capacitor; The negative electrode current collector 5 was accommodated in a concave container 1 provided in advance. The concave container 1 was made of alumina having a square shape with an outer dimension of each wall surface of about 5 mm on a side.

  After injecting the same amount of the electrolyte as the polarizable electrode volume so that the electrode is sufficiently immersed in the concave container 1, a metal metal frame 6 made of metal that has been brazed in advance to the open end of the concave container 1. And the sealing plate 11 were welded to form a second capacitor. Here, the negative electrode current collector 5 and the positive electrode current collector 2 are not electrically connected to the sealing plate 11 and the metal frame 6, and the negative electrode current collector 5 is connected to the negative electrode connection terminal 10 to be soldered to the substrate. Electrically connected. As described above, the positive electrode connection terminal 9 is electrically connected to the positive electrode current collector 2 formed through the side wall of the concave container 1.

  Next, a third capacitor of the present invention is shown in FIG. A part of the positive electrode current collector 2 in the second capacitor is extended to the inner wall surface facing the opening of the concave container 1, that is, the inner wall bottom surface of the concave container 1, and the area of the positive electrode current collector 2a is enlarged. Yes, except for this structure, it was configured in the same manner as the second capacitor.

  In the fourth capacitor, the polarizable electrodes 3a and 3b in the first capacitor have a size of 3.8 mm square and a thickness of 0.5 mm, and the outer dimension of the bottom surface of the inner wall of the concave container 1 is 5.0 mm in length and 1 mm in width. The configuration was the same as that of the first capacitor except that the length of the inner wall side surface of the concave container 1 was 5 mm, that is, the length of the side in the direction perpendicular to the inner wall bottom surface was 5.0 mm.

  In order to compare with the first to fourth capacitors of the present invention, a capacitor having a conventional structure shown in FIG. 4 was used. In the conventional capacitor, the polarizable electrode and the electrolyte were prepared in the same manner as the first capacitor.

  A positive electrode formed by plating the two polarizable electrodes 23a and 23b, which are produced in the same manner as the first capacitor of FIG. 1, with a cellulose separator 24 interposed therebetween. The current collector 22 was accommodated in a concave concave container 21 provided in advance. The concave container 21 was made of alumina having a square shape with an outer dimension of each wall surface of about 5 mm on a side.

  After injecting the same amount of the electrolyte as the polarizable electrode volume so that the polarizable electrode is sufficiently immersed in the concave container 21, a metal metal frame brazed in advance to the open end of the concave container 21 is provided. The body 26 and the sealing plate 27 were sealed by welding to form the capacitor of FIG. Here, the negative electrode current collector 25 provided by plating inside the sealing plate 27 is electrically connected to a metal frame 26 made of metal and a negative electrode connection terminal 29 to be soldered to the substrate. The body 22 is electrically connected to a positive electrode connection terminal 28 that is soldered to the substrate.

  Immediately after assembling the first to fourth capacitors manufactured by the manufacturing method described above and the capacitor of the conventional structure as a comparative example, each is subjected to reflow soldering (maximum temperature 260 ° C.) and subjected to cycle charge / discharge. The internal resistance of was compared. The results are shown in Table 1. The cycle charge / discharge was performed under the following conditions. Charging was performed with constant voltage charging of 3.3 V (maximum current limited to 0.5 mA) for 1 hour, and discharging was performed with constant current discharging of 0.2 mA (end voltage of 2.0 V). The number of repetitions was 200.

  As can be seen from Table 1, the first capacitor has a lower internal resistance after reflow soldering than the conventional structure. This is because, in the first capacitor structure, the adhesiveness between a pair of polarizable electrodes that accumulates electric charges even if the sealing plate is bent due to temperature change during reflow soldering, and the polarizable electrode and current collector This is thought to be due to the fact that the adhesiveness does not decrease.

  Next, in the second capacitor, the internal resistance after cycle charge / discharge is reduced as compared with the first capacitor. Since the sealing plate and metal frame for sealing are not connected to the pair of polarizable electrodes that accumulate electric charge and are electrically insulated, the influence on the internal resistance of the sealing plate is eliminated. It is thought that.

  In the third capacitor, the internal resistance is reduced as compared with the first capacitor. This is probably because the area of the current collector was larger than that of the first capacitor. Next, in the fourth capacitor, the amount of increase in internal resistance due to reflow soldering or cycle charge / discharge was less than that in the first capacitor. This is thought to be because the influence on the internal resistance of the sealing plate was reduced by making the sealing surface the smallest surface of the concave container.

As described above, as in the conventional structure, a current collector is provided on the back surface of the sealing plate by laminating polarizable electrodes or separators from the bottom surface of the concave container, or the sealing plate itself is used as the current collector. In the present invention, the side surface of the concave container is used as the lower surface, and a polarizable electrode, a separator, or the like is laminated between the opposite side surfaces of the concave container so as to face the side surface of the concave container, and the current collector is disposed on the side surface of the concave container Therefore, even if the sealing plate is deformed, it is possible to prevent the deformation from affecting the contact surface of the polarizable electrode and the current collector. Moreover, since a space can be secured between the laminate and the sealing plate, it is possible to further prevent the deformation of the sealing plate from being transmitted to the laminate.

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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Concave container 2 Positive electrode collector 3a Polarization electrode 3b Polarization electrode 4 Separator 5 Negative electrode collector 7 Sealing plate 7a Negative electrode connection terminal 8 Positive electrode connection terminal 9 Positive electrode connection terminal 10 Negative electrode connection terminal

Claims (5)

  A capacitor in which a storage container constituted by a concave container and a sealing lid is used, and a pair of positive and negative polarizable electrodes and a separator are stored and stacked along the side surface between the opposing side surfaces of the concave container.   The capacitor according to claim 1, wherein a current collector is formed on at least a side inner wall of the concave container, and the current collector and the polarizable electrode are electrically connected.   The capacitor according to claim 2, wherein the current collector is extended to an inner wall of a bottom surface of the concave container.   4. The capacitor according to claim 1, wherein the sealing lid is electrically insulated from the pair of positive and negative polarizable electrodes. 5. The capacitor according to claim 1, wherein an area of the sealing lid is smaller than an area of one of the opposing side wall surfaces of the concave container.

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