JP2949530B2 - Multilayer electric double layer capacitors - Google Patents

Abstract

PURPOSE:To make a laminated electric double layer capacitor thin and to make a liquid hard to leak in the laminated electric double layer capacitor which has been housed inside one case in a state that two capacitor elements have been laminated in series. CONSTITUTION:In a state that the peripheral edge part of an intermediate electrode plate 48 composed of a metal material which is rich in malleability has been pressurized, sandwiched and held by the peripheral edge part 38 of a first case half-body 40 and by the peripheral edge part 39 of a second case half-body 41, the individual peripheral edge parts 38 and 39 of the first and second case half-bodies 40 and 41 are sealed. A first electrode plate 44 and a second electrode plate 45 which are exposed in openings 46 and 47 in the first and second case half-bodies 40 and 41 give respective external terminal means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer electric double-layer capacitor having a plurality of capacitor elements stacked in series, and more particularly to a structure for accommodating a capacitor element in such a multilayer electric double-layer capacitor. It is about.

[0002]

2. Description of the Related Art In recent years, with the development of semiconductor technology, a CPU is often mounted not only on industrial equipment but also on consumer equipment. In these devices, a RAM is used as a memory for programs and data, but a voltage of about 2 V or more must be constantly applied to the RAM in order to retain the memory.

There are two types of backup power supplies for supplying such a memory protection voltage: a battery and an electric double-layer capacitor. The latter is, from the viewpoint of maintainability, ease of use, and design freedom, etc. Because it ’s good,
Recently, electric double layer capacitors have become the mainstream of backup power supplies.

On the other hand, the operating voltages of semiconductor devices such as CPUs and RAMs have tended to be reduced, and this has led to a dramatic increase in the mounting of such devices on portable devices. There is also a strong demand for capacitors to be smaller and thinner.

[0005] It is essential to use an electrolytic solution for an electric double layer capacitor. As the electrolytic solution, a non-aqueous solvent-based organic electrolytic solution or an aqueous electrolytic solution is usually used. There is a difference in decomposition voltage between the two, and in general, the organic electrolyte is easier to obtain a higher voltage per unit cell. Are suitable.

FIG. 3 shows a general structure of a unit cell of an electric double layer capacitor using an organic electrolyte. Referring to FIG. 3, in electric double layer capacitor 1, polarizable electrodes 2 and 3 made of a carbon-based material such as activated carbon are opposed to each other with a separator 4 interposed therebetween to form element 5. After the element 5 is impregnated with the electrolytic solution, the element 5 is housed in the case provided by the case halves 6 and 7 while being sandwiched by the first and second case halves 6 and 7. . The first and second case halves 6 and 7 also serve as external terminal means, and are electrically insulated from each other by the insulating gasket 8.

The unit cell of the electric double layer capacitor 1 using such an organic electrolyte has a withstand voltage of about 1.8.
V to about 2.8V.

Therefore, in order to match the rated voltage, a required number of unit cells are used in a state of being connected in series. Usually, in order to connect the required number of unit cells in series, the corresponding number of electric double layer capacitors 1 as shown in FIG. 3 are stacked and integrated. At present, semiconductor devices of 5 V are mainly used, so that two electric double layer capacitors 1 are stacked and set to a rated voltage of 5.5 V is mainly used.

Further, unlike the above-described structure, an integrated two-cell laminated electric double-layer capacitor in which two sets of capacitor bodies are accommodated in a single metal outer case in a state of being connected in series is disclosed in Japanese Patent Application Laid-Open No. H10-157,086. This is proposed in Japanese Patent Application Laid-Open No. 63-187613.

FIG. 4 shows an example of the electric double layer capacitor proposed in the above publication. Referring to FIG. 4, electric double layer capacitor 9 includes capacitor elements 10 and 11 impregnated with an electrolytic solution. Capacitor element 10 includes polarizable electrodes 13 and 14 opposed to each other with a separator 12 interposed therebetween.
1 includes polarizable electrodes 16 and 17 opposed to each other with a separator 15 interposed therebetween. The capacitor element 10 includes a first electrode plate 18 serving also as an external terminal means and an outer case,
Capacitor elements 10 and 11 are sandwiched between second electrode plate 19 and capacitor element 1.
1 is sandwiched between the above-mentioned second electrode plate 19 and a third electrode plate 20 which also serves as an external terminal means and an exterior case. Further, the first, second and third electrode plates 18, 19, 2
0, the insulative gasket 2
By 4 and 25, they are electrically insulated and integrally joined.

According to the structure shown in FIG. 4, the number of steps is not much different from the case of assembling the electric double layer capacitor 1 providing the unit cell shown in FIG. The multilayer capacitor 9 can be manufactured.

[0012]

In recent years, as electronic devices have become smaller and thinner, there has been an increasing demand for smaller and thinner backup power supplies mounted thereon. There is a strong demand for a semiconductor element having a height equal to or less than the outer height of the semiconductor element.

In the structure shown in FIG. 3, since the thickness of the insulating gasket 8 is related to the entire thickness of the electric double layer capacitor 1, it is necessary to reduce the thickness of the insulating gasket 8 of the electric double layer capacitor 1. Although effective in reducing the thickness, the thickness of the insulating gasket 8 cannot be extremely reduced from the viewpoint of sealing properties and strength. Also, in order to cope with the currently mainstream rated voltage of 5.5 V, it is necessary to stack two or more electric double-layer capacitors 1, and there is also a limit in thinning in this regard.

On the other hand, in the structure shown in FIG. 4, two capacitor elements 10 and 11 are stacked and integrated in advance, but the insulating gaskets 24 and In addition to using 25, the structure of the sealing portion is more complicated than the structure of FIG.

Further, in each structure as shown in FIGS. 3 and 4, a resin is used as the insulating gaskets 8, 24, and 25. Such a resin gasket is provided between the upper and lower peripheral portions of the case. Sealing is achieved by clamping in a pressurized state.
There was also an essential problem that the electrolyte was easy to leak.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multilayer electric double layer capacitor having a two-cell laminated integral structure, which can be reduced in thickness and in which liquid leakage hardly occurs.

[0017]

The present invention comprises a separator impregnated with a non-aqueous solvent-based electrolyte, and a pair of polarizable electrodes facing each other with the separator interposed therebetween.
The present invention is directed to a multilayer electric double-layer capacitor in which first and second capacitor elements are stacked in series, and is characterized by having the following configuration in order to solve the above-described technical problem.

That is, in the multilayer electric double layer capacitor according to the present invention, the first electrode plate which is in contact with the upper surface of the upper first capacitor element is disposed in close contact with the inner surface via an insulating layer. A second case half, having a body and a second electrode plate in contact with the lower surface of the lower second capacitor element in close contact with the inner surface with an insulating layer interposed therebetween, and having a rising shape at a peripheral edge; An intermediate electrode plate disposed between the first and second capacitor elements so as to contact a lower surface of the one capacitor element and an upper surface of the second capacitor element. The peripheral portions of the first and second case halves are sealed while the peripheral portions of the intermediate electrode plate are pressed and clamped by the peripheral portions of the first and second case halves. Further, openings are formed in the first and second case halves to expose respective portions of the first and second electrode plates.

Preferably, at least the peripheral portion of the intermediate electrode plate is formed of a highly malleable metal such as aluminum or an aluminum alloy.

In addition, the sealing at the peripheral edges of the first and second case halves is performed by pressing and holding the peripheral edges of the first and second case halves so that the peripheral edge of the intermediate electrode plate is plastically deformed. It is sufficient to perform welding, but it is also possible to further enhance the sealing performance by welding a part of such a peripheral portion.

[0021]

According to the present invention, sealing is achieved by pressing and clamping the peripheral edge of the intermediate electrode plate by the peripheral edge of the first and second case halves while being plastically deformed.

Further, since the sealing portion is provided as described above, the first and second case halves have the same potential as the intermediate electrode plate, and these cannot be used as external terminal means. Therefore, each part of the first and second electrode plates exposed at the openings respectively formed in the first and second case halves is used as external terminal means.

[0023]

Therefore, according to the present invention, the intermediate electrode plate can function as a gasket without using an insulating gasket made of resin, so that the multilayer electric double-layer capacitor can be significantly thinned. be able to.

In the sealing structure, each peripheral portion of the first and second case halves is brought into close contact with the peripheral portion of the intermediate electrode plate with plastic deformation of the peripheral portion of the intermediate electrode plate. Is provided by the insulating layer located between each of the first and second case halves and the first and second electrode plates, and is caused by stress relaxation as in the case of using a resin gasket. Leakage of the electrolyte solution is less likely to occur.

[0025]

FIG. 1 is a sectional view showing a multilayer electric double layer capacitor 26 according to an embodiment of the present invention.

The multilayer electric double layer capacitor 26 has a case 27 in which first and second capacitor elements 28 and 29 are accommodated in a state of being stacked in series. The first capacitor element 28 includes a separator 30 impregnated with a non-aqueous solvent-based electrolyte and a pair of polarizable electrodes 31 and 3 facing each other with the separator 30 interposed therebetween.
2 is provided. On the other hand, the second capacitor element 29 similarly includes a separator 33 and a pair of polarizable electrodes 34 and 35.

The case 27 includes first and second case halves 40 and 41 having main plane portions 36 and 37 and peripheral portions 38 and 39, respectively. First and second electrode plates 44 and 45 serving as external terminal means are respectively provided on the inner surfaces of the first and second case halves 40 and 41 via insulating layers 42 and 43 made of resin or the like.
Are arranged in close contact. The insulating layers 42 and 43 are preferably composed of a heat-adhesive film. The heat adhesive film is excellent in that a thin, flat, and pinhole-free layer can be easily obtained. Openings 46 and 47 are formed in the first and second case halves 40 and 41 to expose portions of the first and second electrode plates 44 and 45, respectively. These first and second case halves 40 and 41 and first and second
For the electrode plates 44 and 45, a metal foil made of stainless steel, aluminum, an aluminum alloy, or the like is advantageously used because corrosion resistance is excellent and the thickness can be reduced.

The first electrode plate 44 contacts the upper surface of the upper first capacitor element 28, while the second electrode plate 45 contacts the lower surface of the lower second capacitor element 29, thereby providing electrical connection. Is connected. Also, the first
Lower surface of capacitor element 28 and second capacitor element 2
An intermediate electrode plate 48 is arranged between first and second capacitor elements 28 and 29 so as to be in contact with the upper surface of capacitor 9. The intermediate electrode plate 48 includes a main plane portion 49 and a peripheral portion 50.
Having. For the intermediate electrode plate 48, a metal foil of aluminum or an aluminum alloy having excellent corrosion resistance and high malleability is advantageously used.

The peripheral portion 39 of the second case half 41 has a rising shape. With the peripheral edge portion 50 of the intermediate electrode plate 48 and the peripheral edge portion 38 of the first case half 40 being sequentially arranged inside the peripheral edge portion 39, the upper end portion of the peripheral edge portion 39 is deformed inward, thereby forming the peripheral edge portion. 38,3
9, 50 are pressed against each other. At this time, the respective peripheral edges 38 and 39 of the first and second case halves 40 and 41
Is pressed while holding the peripheral portion 50 of the intermediate electrode plate 48 under plastic deformation, whereby the peripheral portions 38 and 39 of the first and second case halves 40 and 41 are sealed. Therefore, the first case half 40 and the intermediate electrode plate 48
Defines the first closed space 51, and the second case half 41 and the intermediate electrode plate 48 define the second closed space 5.
2 is specified. In addition, the peripheral portion 3 of the first case half 40
It is preferable that the projections 8 are provided continuously on the entire circumference of the projection 8. The protrusions 53 allow the peripheral portion 38 of the first case half 40 and the peripheral portion 5 of the intermediate electrode plate 48 to move.
The adhesion with 0 is further improved.

The sealing provided to the case 27 is normally sufficiently achieved only by pressing the peripheral portions 38, 39, and 50 together as described above. Laser welding is performed on the press contact portion 54 between the first and second case halves 40 and 41, or the contact portion 55 between the first and second case halves 40 and 41 and the intermediate electrode plate 48 is provided.
Laser or electric resistance welding on the
What is necessary is just to weld both the press contact part 54 and the contact part 55.

An example of an assembling process of the multilayer electric double layer capacitor 26 shown in FIG. 1 will be described below.

An insulating layer 42 is provided on the inner surface of the first case half 40.
The heat-adhesive film and the first electrode plate 44 to be
These are tightly fixed by heating while applying pressure. At this time, in order to expose a part of the first electrode plate 44 from the opening 46, the first case half 40 and the heat-adhesive film are provided with an opening in a portion corresponding to the opening 46 in advance. Similarly, the second electrode plate 45 is formed on the inner surface of the second case half 41 by using a heat-adhesive film to be the insulating layer 43.
Is tightly fixed.

On the other hand, the first and second capacitor elements 28
And 29 are obtained by laminating polarizable electrodes 31, 32 and 34, 35 made of an activated carbon sheet on both surfaces of separators 30 and 33 with an adhesive or a pressure-sensitive adhesive, and then impregnating with an electrolyte. .

Next, the second capacitor element 29, the intermediate electrode plate 48, the first capacitor element 28 and the first case half 40 are sequentially stacked on the second case half 41, By crimping the peripheral portion 39, the peripheral portions 38, 39, 50 are integrated.

FIG. 2 shows a multilayer electric double layer capacitor 26a according to another embodiment of the present invention. The multilayer electric double layer capacitor 26a has all the elements included in the electric double layer capacitor 26 shown in FIG. Therefore, common elements are denoted by the same reference numerals, and duplicate description will be omitted.

The multilayer electric double-layer capacitor 26a shown in FIG. 2 is improved in external terminal means to facilitate connection with an external circuit board or the like. More specifically, the first and second electrode plates 44 and 45 are placed outside the first and second case halves 40 and 41 via conductive members 56 and 57 located at openings 46 and 47, respectively. It is electrically connected to first and second terminal boards 58 and 59 provided. Conductive members 56 and 57
The first and second terminal plates 58 and 59 are electrically insulated from the first and second case halves 40 and 41 by insulating layers 60 and 61, respectively.

The insulating layers 60 and 61 are preferably made of a heat-adhesive film. Also, the conductive members 56 and 57 are preferably provided by a silver paste.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a multilayer electric double layer capacitor 26 according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a multilayer electric double layer capacitor 26a according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a conventional electric double layer capacitor 1 having the most basic structure.

FIG. 4 is a cross-sectional view showing a conventional two-cell integrated type electric double layer capacitor 9;

[Explanation of symbols]

 26, 26a Multilayer electric double layer capacitor 28 First capacitor element 29 Second capacitor element 30, 33 Separator 31, 32, 34, 35 Polarization electrode 38, 39, 50 Peripheral edge 40 First case half 41 Second case Half body 42, 43 Insulating layer 44 First electrode plate 45 Second electrode plate 46, 47 Opening 48 Intermediate electrode plate 54 Press-contact portion 55 Adhesive portion 56, 57 Conductive member 58, 59 Terminal plate 60, 61 Insulating layer

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masato Higuchi 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Murata Manufacturing Co., Ltd. (56) References JP-A-1-140553 (JP, A) Hei 1-313918 (JP, A) Japanese Utility Model Showa 62-41665 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01G 9/016 H01G 9/155

Claims (1)

(57) [Claims] 1. A laminated type in which a first and a second capacitor element, each including a separator impregnated with a non-aqueous solvent-based electrolyte and a pair of polarizable electrodes facing each other via the separator, are laminated in series. In the electric double-layer capacitor, a first electrode plate in contact with an upper surface of the upper first capacitor element is disposed in close contact with an inner surface via an insulating layer, and a first case half and a lower second capacitor element are provided. A second electrode plate that is in contact with the lower surface, is disposed in close contact with the inner surface via the insulating layer, and has a rising shape at a peripheral edge thereof;
A case half, and an intermediate electrode plate disposed between the first and second capacitor elements so as to contact a lower surface of the first capacitor element and an upper surface of the second capacitor element; In a state where the peripheral edge of the electrode plate is pressed and clamped by the peripheral edges of the first and second case halves, the peripheral edges of the first and second case halves are sealed and the first and second case halves are sealed. An opening for exposing a part of each of the first and second electrode plates is formed in the first and second case halves, respectively.