JPH0669080A - Electrochemical device - Google Patents

Abstract

PURPOSE:To increase the reliability of the electric contact state of a case used also as a terminal with a functional substance at its inside in an electrochemical device such as an electric double layer capacitor or a battery. CONSTITUTION:A conductive elastic body 21 composed of, e.g. a leaf spring is inserted between a case half-body 14 provided at a case 12 and a functional substance 20 on one side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochemical device such as an electric double layer capacitor or a battery, and more particularly to a case which also serves as a terminal in such an electrochemical device and a functional substance contained therein. The present invention relates to the improvement of the electrical connection structure with.

[0002]

BACKGROUND OF THE INVENTION An example of a conventional electrochemical device of interest to the present invention is shown in FIG. The thin and flat electrochemical device 1 shown in FIG.
No. 140553. This electrochemical device 1 constitutes an electric double layer capacitor or a battery.

This electrochemical device 1 is provided with a case 2 which also serves as a terminal. The case 2 comprises first and second case halves 3 and 4 made of a metal plate or foil such as stainless steel. The peripheral edges of each of the case halves 3 and 4 are joined by welding to each other in order to provide the case 2 with a hermetically sealed structure. A terminal plate 5 made of a metal plate or foil such as stainless steel or aluminum is arranged along the inner surface of the first case half body 3. The terminal board 5 is brought into close contact with the first case half body 3 via the insulating resin layer 6. Further, the first case half 3 and the insulating resin layer 6 are formed with an opening 7 that exposes a part of the terminal plate 5.

In the case 2 described above, the separator 8 and the first and second functional substances 9 and 10 located with the separator 8 interposed therebetween are housed. When the electrochemical device 1 is an electric double layer capacitor, the first and second functional substances 9 and 10 are polarizable electrodes, respectively. On the other hand, when the electrochemical device 1 is a battery, one is a positive electrode active material. And the other is the negative electrode active material.

In such an electrochemical device 1, the first
The functional substance 9 is in electrical contact with the terminal board 5, and the second functional substance 10 is in electrical contact with the second case half 4. Therefore, the terminal plate 5 serves as one terminal, and the second case half body 4 and the first case half body 3 electrically connected thereto serve as the other terminal.

[0006]

In the electrochemical device 1 described above, the electric contact between the first and second functional substances 9 and 10 and the terminal plate 5 and the second case half 4 is ensured. In order to do so, the functional substances 9 and 10 must be properly pressurized by the case 2.

However, such an electrochemical device 1
When thin materials are used for the case halves 3 and 4 and the terminal plate 5 in order to make them thinner, their strength is reduced. Therefore, it is necessary to properly maintain the pressure applied to the functional substances 9 and 10 by the case 2. You may not be able to Further, when a voltage is applied, residual water in the electrolytic solution is decomposed to generate a small amount of gas, which also hinders the above-mentioned contact state. Therefore, in the electrochemical device 1, the contact resistance between the case half body 4 and the functional substance 10 and between the terminal plate 5 and the functional substance 9 increases, and as a result, the internal resistance of the entire electrochemical device 1 also increases.

Further, when the case 2 is deformed by an action from the inside such as generation of decomposition gas due to abnormal external pressure or application of overvoltage, the case 2 and the functional substances 9 and 1 are deformed.
There is a gap between the case half and the case half 4
The contact between the functional substance 10 and the contact between the terminal plate 5 and the functional substance 9 tends to be unstable. In the worst case, the case half 4 and the functional substance 10 or the terminal plate 5 and the functional substance 9 may be completely separated from each other, and the original function of the electrochemical device 1 may be lost.

Therefore, an object of the present invention is to provide an electrochemical device capable of reliably and stably making electrical contact between a case and a functional substance in order to solve the above-mentioned problems.

[0010]

The present invention comprises a case,
The present invention is directed to an electrochemical device that includes a separator and first and second functional substances that sandwich the separator and that is housed in the case. It is characterized in that an elastic body having conductivity is inserted between at least one of the first and second functional substances.

[0011]

The elastic body having conductivity functions itself as a means for establishing an electrical connection between the case and the functional substance, and at the same time, causes the elasticity to act so as to increase the pressure applied to the functional substance by the case.

[0012]

According to the present invention, therefore, the presence of the elastic body having conductivity ensures the electrical contact state between the case and the functional substance, either directly or through the elastic body. Can be one. Therefore, the contact resistance between the case and the functional substance can be kept small, and as a result, the internal resistance of the whole electrochemical device can be kept low.

Even when the case is deformed by the external pressure or the action from the inside, by the action of the elastic body,
The functional substance can be made to follow such deformation in order to maintain an appropriate electrical contact state between the case and the functional substance. Therefore, it is possible to prevent the function of the electrochemical device from being deteriorated or lost due to the deformation of the case.

Further, the reliable electrical contact between the case and the functional substance by the elastic body does not require repair, and also brings about the reliable mechanical contact between the case and the functional substance.
As a result, it is possible to prevent the functional substance from being displaced inside the electrochemical device due to vibration or the like, and therefore,
Short circuit failure due to contact between the case and the functional substance or between the two functional substances can be prevented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to FIGS. 1 to 4, respectively. It constitutes a double layer capacitor or battery.

FIG. 1 shows a first embodiment of the present invention. The electrochemical device 11 shown here is the same as that shown in FIG.
The electrochemical device 1 includes many elements in common.

Referring to FIG. 1, the electrochemical device 11 includes a case 12. The case 12 comprises first and second case halves 13 and 14, each made of a metal plate or foil such as stainless steel. These case halves 13 and 14 are joined by welding their peripheral portions to each other in order to provide a hermetically sealed structure to the case 12. Along the inner surface of the first case half 13 is arranged a terminal plate 15 which is a part of the case 12 and is made of a metal plate or foil such as stainless steel or aluminum. The terminal board 15 is in close contact with the first case half body 13 through the insulating resin layer 16. An opening 17 for exposing a part of the terminal board 15 is formed in the first case half body 13 and the insulating resin layer 16. The insulating resin layer 16 is made of, for example, a heat adhesive film or an adhesive.

In the case 12 described above, the separator 1
8 and the first and second functional substances 19 and 20 positioned with the separator 18 interposed therebetween are stored. When the electrochemical device 11 is an electric double layer capacitor, the first and second functional substances 19 and 20 are polarizable electrodes, respectively. On the other hand, when the electrochemical device 11 is a battery, one is a positive electrode active material. And the other is the negative electrode active material.

Also in this electrochemical device 11, the terminal plate 15 functions as one of the terminals, as in the above-described electrochemical device 1, and the first and second case halves 13 and 14 are used.
Functions as the other terminal. This embodiment has a characteristic structure as described below.

Second case half 14 and second functional substance 2
An elastic body 21 having conductivity is inserted between 0 and 0.
The elastic body 21 is provided by a thin leaf spring made of metal, for example. The elastic body 21 exerts an elastic force between the second case half body 14 and the second functional substance 20 to achieve a reliable electrical connection between them, and based on its elasticity, The first functional substance 19 is brought into pressure contact with the terminal board 15 to ensure reliable electrical contact during this time.

FIG. 2 shows a second embodiment of the present invention. The electrochemical device 22 shown here is the electrochemical device 1 according to the first embodiment described above in that there is no terminal plate.
It is very different from 1.

The electrochemical device 22 includes a case 23. The case 23 comprises first and second case halves 24 and 25, each made of a metal plate or foil, such as stainless steel, for example. Since the case halves 24 and 25 provide the case 23 with a hermetically sealed structure,
The peripheral portions are bonded to each other via the insulating resin layer 26.

In the case 23, the separator 27 and the first and second functional substances 28 and 29 positioned with the separator 27 sandwiched therebetween are housed.

Second case half 25 and second functional substance 2
An elastic body 30 having conductivity is inserted between the elastic body 30 and 9. Like the elastic body 21, the elastic body 30 is also provided by a thin leaf spring made of metal, for example.

In the electrochemical device 22, the first functional substance 28 comes into contact with the first case half 24, and the first case half 24 functions as one terminal. On the other hand, the second functional substance 29 is electrically connected to the second case half body 25 through the elastic body 30, and the second case half body 25 functions as the other terminal. And the elastic body 3
As with the elastic body 21 described above, 0 enables a reliable pressure contact state between the functional substances 28 and 29 and the case 23.

FIG. 3 shows a third embodiment of the present invention. The electrochemical device 40 shown in FIG. 3 is characterized by including two terminal plates, as compared with the electrochemical device 11 shown in FIG.

The electrochemical device 40 includes a case 41. The case 41 includes first and second case halves 45 and 46 each made of a laminated film having a three-layer structure in which the insulating resin layers 43 and 44 are formed on both surfaces of the metal foil 42. These case halves 45 and 46 are joined to each other by, for example, welding their peripheral portions to each other in order to provide a hermetically sealed structure to case 41. Further, along the inner surface of each of the first and second case halves 45 and 46, the first and second metal plates or foils that form a part of the case 41 and are made of, for example, stainless steel or aluminum. The terminal plates 47 and 48 are arranged respectively. These terminal plates 47 and 48 are preferably welded to the case halves 45 and 46, respectively, thereby ensuring a close contact between them. The first and second case halves 45 and 46 are provided with openings 49 and 50 respectively exposing a part of the first and second terminal plates 47 and 48, respectively.

In the case 41 described above, the separator 5
1 and the first and second functional substances 52 and 53 positioned with the separator 51 sandwiched therebetween are stored. Further, an elastic body 54 having conductivity is arranged between the second functional substance 53 and the second terminal plate 48. This elastic body 54
Similarly to the elastic body 21 described above, the elastic body 21 is also provided by a thin leaf spring made of metal, for example.

In the electrochemical device 40, the first functional substance 52 comes into contact with the first terminal plate 47 and causes the first terminal plate 47 to function as one terminal. In addition, the second functional substance 53 is electrically connected to the second terminal plate 48 via the elastic body 54, and causes the second terminal plate 48 to function as the other terminal. At this time, the elastic body 54 exerts an elastic force between the second functional substance 53 and the second terminal plate 48, so that the functional substances 52 and 53 and the case 41 are surely brought into contact with each other under pressure. To achieve.

FIG. 4 shows a fourth embodiment of the present invention. The electrochemical device 31 shown in FIG. 4 includes a case 32. The case 32 comprises first and second case halves 33 and 34, each made of a metal plate or foil such as stainless steel. The case halves 33 and 34 are mechanically integrated while being electrically insulated from each other by being caulked at their peripheral portions via an insulating gasket 35, thereby providing an airtight case 32. Is formed. A separator 36 and first and second functional substances 37 and 38 are housed in the case 32. The peripheral portion of the separator 36 is sandwiched between the gasket 35 and the second case half body 34, and is positioned thereby.

Second case half 34 and second functional substance 3
An elastic body 39 having electrical conductivity is inserted between the elastic body 39 and the sheet 8. The elastic body 39 is provided by, for example, conductive rubber.

In this electrochemical device 31, the first functional substance 37 electrically contacts the first case half 33,
The first case half 33 functions as one terminal. On the other hand, the second functional substance 38 is electrically connected to the second case half body 34 via the elastic body 39, and the second case half body 34 functions as the other terminal. And
The elastic body 39 is the elastic body 21, 3 in the above-described embodiment.
Like 0 and 54, it enables reliable pressure contact between the case 32 and the functional substances 37 and 38.

Although the present invention has been described above with reference to several illustrated embodiments, further modifications are possible within the scope of the present invention.

For example, the elastic bodies 21, 30, 39, 54
Is not only inserted between the second case half 14, 25, 34 or the second terminal plate 48 and the second functional substance 20, 29, 38, 53, but also improves its reliability. For this purpose, it may be fixed to either or both of the second case half or the terminal plate and the second functional substance by adhesion or the like.

Further, the elastic body 39 made of conductive rubber shown in FIG. 4 may be used as a substitute for the elastic body 21, 30 or 54 in the embodiment shown in FIG. 1, 2 or 3. On the contrary, the elastic body 21, 30 or 54 formed of the thin leaf spring shown in FIG. 1, FIG. 2 or FIG. 3 may be used instead of the elastic body 39 shown in FIG.

Further, the elastic body is, in each of the above-mentioned embodiments,
Although it is used so as to contact the second functional substance, it may be used so as to contact the first functional substance or two elastic bodies may be used so as to contact both of them. If two elastic bodies are used, then such elastic bodies are:
Those made of thin leaf springs or those made of conductive rubber are used, respectively, and those made of thin leaf springs and those made of conductive rubber may be mixed.

Further, the elastic body is not limited to the above-mentioned thin leaf spring or the one made of conductive rubber, and other elements capable of being conductive elastic bodies may be used.

Finally, the results of experiments conducted to compare the characteristics of the electrochemical device according to the present invention and the conventional electrochemical device will be described. Table 1 shows the internal resistance of the electric double layer capacitors used as the samples.
The initial internal resistance and the internal resistance after the high temperature load test are shown. In Table 1, Example 1, Example 2, and Example 3
And Example 4 correspond to the examples shown in FIGS. 1, 2, 3 and 4, respectively, and the comparative example corresponds to the conventional technique shown in FIG.

[0039]

[Table 1] From Table 1, according to the examples of the present invention, compared with the comparative example, the initial internal resistance can be reduced from about 1/4 to 1/10, and further, in the internal resistance after the high temperature load test, , It can be seen that it can give a more significant difference. Each sample shown in Table 1 is an electric double layer capacitor,
It was confirmed that the same effect can be obtained also in the case of batteries.

[Brief description of drawings]

FIG. 1 is an electrochemical device 1 according to a first embodiment of the present invention.
It is sectional drawing which shows 1.

FIG. 2 is an electrochemical device 2 according to a second embodiment of the present invention.
It is sectional drawing which shows 2.

FIG. 3 is an electrochemical device 4 according to a third embodiment of the present invention.
It is sectional drawing which shows 0.

FIG. 4 is an electrochemical device 3 according to a fourth embodiment of the present invention.
It is sectional drawing which shows 1.

FIG. 5 is a cross-sectional view showing a conventional electrochemical device 1.

[Explanation of symbols]

 11, 22, 31, 40 Electrochemical device 12, 23, 32, 41 Case 18, 27, 36, 51 Separator 19, 28, 37, 52 First functional substance 20, 29, 38, 53 Second functional substance 21, 30, 39, 54 Elastic body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michinobu Maesaka 2 26-10 Tenjin Tenjin, Nagaokakyo, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor Tatsuo Kunishi 226-10 Tenjin Tenjin, Nagaokakyo, Kyoto Murata Manufacturing Co., Ltd. (72) Inventor Koichi Watanabe 2 26-10 Tenjin, Nagaokakyo City, Kyoto Prefecture Murata Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. A case and a case housed in the case,
An electrochemical device comprising a separator and first and second functional substances sandwiching the separator, wherein the electrochemical device has conductivity between the case and at least one of the first and second functional substances. An electrochemical device, wherein an elastic body is inserted.