Electrochemical device

Abstract

An electrochemical device includes a pair of electrodes, an electrolytic solution, and a container for containing the pair of electrodes and the electrolytic solution. The container includes a frame body having concave shape and a sealing plate configured to seal an opening of the frame body, and an electronic device is buried in the frame body or the sealing plate.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2005-190302, filed on Jun. 29; the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electrochemical device including a pair of electrodes, an electrolytic solution, and a container for housing the pair of electrodes and the electrolytic solution.

2. Description of the Related Art

Electrochemical devices having high volume energy density, such as chemical cells and electric double layer capacitors, have been conventionally used in back-up power supplies and auxiliary power supplies for cellular telephones and home appliances. A higher performance of such electrochemical devices has been expected.

These electrochemical devices are soldered and mounted on printed circuit boards of various electronic equipments. Conventional electrochemical devices are formed into round shapes like coins, buttons, and the like. Accordingly, it is necessary to attach terminals to solder the electrochemical devices onto printed circuit boards. Moreover, due to the round shapes, areas assumed for mounting were set larger than those of containers of the electrochemical devices. In this context, an electric dole layer capacitor has been disclosed, which includes a concave container made of a ceramic, resin or the like, and a sealing plate having a metallic portion (see Japanese Unexamined Patent Publications Nos. Hei 11(1999)-54387 and 2001-216952, for example). Such techniques make it possible to reduce the number of steps of attaching terminals, and to reduce mounting areas.

Meanwhile, in these electrochemical devices, level of the volume energy density increases adverse effects when a current surge and overheat occur. For this reason, actual use of an electrochemical device using an organic electrolytic solution, it is necessary to provide electronic devices including a protective device and a temperature sensor, for protecting the electrochemical device against current surge and overheat, and thereby improving reliability. According, there is a demand for reduction in an installation space in the state where these components are mounted. To meet this demand, disclosed is a technique for an electrochemical device using a flexible film, to which a protective device is attached, as an exterior bag. This electrochemical device is configured to transfer internal heat reliably to the protective device without changing the maximum thickness of the electrochemical device, and to improve safety (see Japanese Unexamined Patent Publication No. 2002-8630, for example). Meanwhile, also disclosed is a structure in which at least two electrochemical devices are laminated such that output terminals of mutually different polarities face each other, and in which a apace formed by an adhesive portion, to which the output terminals of the two or more electrochemical devices are drawn out, constitutes a space having greater thickness than thicknesses of the electrochemical devices (see Japanese Unexamined Patent Publication No. 2003-257393, for example).

SUMMARY OF THE INVENTION

The inventors of the present invention have focused on an aspect to bury an electric device inside a frame having concave shape or sealing plate. In this way, the inventors have accomplished the present invention.

The aspect of the present invention is an electrochemical device including a pair of electrodes, an electrolytic solution and a container for housing the pair of electrodes and the electrolytic solution. The container includes a frame body having concave shape and a sealing plate configured to seal an opening of the frame body, and an electronic device is buried inside any one of the frame body and the sealing plate.

Here, the “electronic device” is defined as a device, a circuit and the like for protecting the electrochemical device against current surge and overheat, and thereby improving reliability. The electronic device, for instance, includes protective devices such as a positive temperature coefficient thermistor (a PTC device), a zener diode and a varistor, and temperature sensors such as a thermocouple, a thermistor and a resistance thermometer bulb.

According to the electrochemical device of this aspect of the present invention, it is possible to save a space and to improve reliability at the same time by burying the electronic device in a fame body or a sealing plate.

Moreover, in the electrochemical device according to this aspect of the present invention, the frame body or the sealing plate where the electronic device is buried, may be made of resin.

In this case, the electronic device may be buried in the frame body or the sealing plate by insert molding, or by welding or attaching two or more resin components constituting the frame body or the sealing plate.

Since the resin, which is used for the frame body or the sealing plate, has the relatively low melting point in a range of 270° C. to 400° C., even the electronic device having low heat resistance can be buried, according to this electrochemical device.

Furthermore, in the electrochemical device according to this aspect of the present invention, the frame body may have a configuration that multiple layers made of ceramics are laminated, and the electronic device may be disposed between the layers and may be buried inside the frame body by sintering the frame body.

According to this electrochemical device, it is possible to form the electronic device as a thin film by the screen printing method, and to bury the electronic device easily in the frame body.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross-sectional view of an electric double layer capacitor according to Example 1.

FIG. 2 is a cross-sectional view of an electric double layer capacitor according to Example 2.

FIG. 3 is a cross-sectional view of an electric double layer capacitor according to Example 3.

FIG. 4 is a cross-sectional view of an electric double layer capacitor according to Example 4.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Next, an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description of the drawings, the same or similar constituents are designated by the same or similar reference numerals. It should be noted, however, that the drawings are schematic and proportions of respective dimensions and the like are different from actual configurations. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is needless to say that the drawings contain parts where relations and proportions of the dimensions are different from one another.

First Embodiment

In a first embodiment, an electric double layer capacitor provided with a fame body having concave shape and a sealing plate will be described as an example of an electrochemical device.

As shown in FIG. 1, the electric double layer capacitor includes a pair of polarizable electrodes 1a and 1b, a separator 2 interposed between the pair of polarizable electrodes 1a and 1b, and an electrolytic solution to be impregnated into the pair of polarizable electrodes 1a and 1b and the separator 2 In addition, a container for housing the pair of polarizable electrodes 1a and 1b and the electrolytic solution includes a frame body 3 having concave shape and a sealing plate 5 for sealing an opening of the frame body 3.

A collector 4a is disposed on an inner bottom surface of the frame body 3, and a collector 4b is disposed on an inner surface of the sealing plate 5 at the side of the polarizable electrode 1b. Note that the polarizable electrode 1a is joined to the collector 4a, and the polarizable electrode 1b is joined to the collector 4b respectively by use of a conductive adhesive layer. Meanwhile, terminals 6a and 6c and a protective device 7 are buried inside the frame body 3 by insert molding, and are electrically connected in series to the pair of polarizable electrodes 1a and 1b.

The collector 4a is electrically connected to the terminal 6c, which is buried in the frame body 3, and the protective device 7 buried inside the frame body 3 is electrically connected to the terminal 6a and the terminal 6c, which are buried in the frame body 3. Furthermore, the collector 4b penetrates a wall surface of the frame body 3, and is electrically connected to a terminal 6b which extends on an outer bottom surface of the frame body 3.

The frame body 3 is made of resin having the melting point in a range of 270° C. to 400° C., such as polyether ether ketone, polyphenylene sulfide and a liquid crystal polymer, so as to withstand a processing temperature in a soldering step at the time of mounting.

The sealing plate 5 is made of a metal material, such as nickel, cupper, brass, zinc, tin, gold, platinum, stainless steels (SUS 444, SUS 239J4L, SUS 317J4L and the like), tungsten, aluminum and cobalt, or a heat-resistant material such as heat-resistant resin, glass, ceramics and ceramic glass. When the sealing plate 5 is made of a metal material, the sealing plate 5 may also function as the collector 4b.

Although FIG. 1 illustrates the structure configured to bury the terminals 6a and 6c and the protective device 7 inside the frame body 3, the sealing plate 5 may be formed of resin, and the terminals and the protective devices may be buried inside the sealing plate 5.

Moreover, instead of insert molding, the protective device 7 shown in FIG. 1 may also be buried by forming the frame body 3 with two or more resin components, and by attaching or welding the protective device 7 so that the protective device 7 is buried in a space between the resin components.

Meanwhile, the conductive adhesive layer may be a mixture of a conductive material, such as gold, platinum, nickel or carbon, and resin, such as polyvinylidene fluoride (PVdF), polyimide (PI) resin, styrene-butadiene resin as typified by styrene-butadiene rubber (SBR) and polyolefin resin as typified by polypropylene and polyethylene, for example.

The polarizable electrodes 1a and 1b are fabricated by punching out an activated carbon sheet made of activated carbon fibers or activated carbon powder by use of a punching die. Note that an electrochemically inactive material having a high specific surface area may be used for the material of the polarizable electrodes. However, it is preferable that the material contains activated carbon powder, which has a large specific surface area, as a main ingredient. In addition to the activated carbon powder, materials having large specific areas, such as carbon black, metal particulates and conductive metal oxide particulates, can be suitably used. Although it is usual to form the electric double layer capacitor as shown in FIG. 1 by using these polarizable electrodes mainly containing the above-mentioned polarizable electrode material for both of positive and negate electrodes, it is also possible to form only one of the positive and negative electrodes as the polarizable electrode, and to form the other electrode as a non-polarizable electrode mainly containing a chargeable and dischargeable non-polarizable electrode material, i.e. an active material for a secondary battery.

The material of the collectors 4a and 4b for electrically connecting the polarizable electrodes 1a and 1b may have excellent conductivity and electrochemical durability. Valve metal, such as aluminum, titanium and tantalum, stainless steel, noble metal such as gold or platinum, and a carbon material, such as conductive rubber containing any of graphite, glassy carbon, and carbon black, can be suitably used.

An insulative membrane or cloth having a high degree of ionic permeation and given mechanical strength is used as the separator 2. Although glass fiber is the most stable for use in the case of reflow soldering, it is also possible to use resin having the heat deformation temperature equal to or above 230° C., such as polyphenylene sulfide, polyethylene terephthalate, polyamide and polyimide. A pore diameter and a thickness of the separator 2 are not particularly limited. These factors are a matter of design to be determined on the bases of a current value of a used appliance and of internal electrical resistance of the capacitor. It is also possible to use porous materials such as ceramics for the separator 2.

The electrolytic solution is an organic electrolytic solution. Here, a solvent used in the electrolytic solution may be capable of dissolving electrolytes, and any publicly-known materials used for electrolytic solutions in electric double layer capacitors and nonaqueous electrolyte secondary batteries are applicable. Such applicable solvents include, for instance, ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, γ-valerolactone, sulfolane, ethylene glycol, polyethylene glycol, vinylene carbonate, chloroethylene carbonate, dimethyl carbonate, diethyl carbonate, methylethyl carbonate, dipropyl carbonate, dibutyl carbonate, dimethoxymethane, dimethoxyethane, methoxyethoxyethane, diethoxyethane, tetrahydrfuran, 2-methyl-tetrahydrofuran, dimethylformamide, dimethylsulfoxide, acetonitrile, methylformate, dioxyolane, 4-methyl-1,3-dioxolane, and the like.

(Operations and Effects)

According to the electrochemical device of the first embodiment, it is possible to save a space and to improve reliability at the same time by burying the electronic device, such as the protective device 7, inside the frame body 3 or the sealing plate 5.

Moreover, the frame body or the sealing plate 5 may be formed of the resin, and the protective device 7 can be buried inside the frame body 3 or the sealing plate 5. The resin, which is used for the frame body 3 or the sealing plate 5, has the relatively low melting point in the range of 270° C. to 400° C. Accordingly, even the electronic device having low heat resistance can be buried.

Second Embodiment

In a second embodiment, an electric double layer capacitor provided with a frame body having concave shape and a sealing plate will be described as an example of the electrochemical device.

As shown in FIG. 4, the electric double layer capacitor includes a pair of polarizable electrodes 1a and 1b, a separator 2 interposed between the pair of polarizable electrodes 1a and 1b, and an electrolytic solution to be impregnated into the pair of polarizable electrodes 1a and 1b and the separator 2. In addition, a container for housing the pair of polarizable electrodes 1a and 1b and the electrolytic solution is configured of a frame body 3 having concave shape and a sealing plate 5 for sealing an opening of the frame body 3.

A collector 4a is disposed on an inner bottom surface of the frame body 3, and a collector 4b is disposed on an inner surface of the sealing plate 5 on the side of the polarizable electrode 1b. Note that the polarizable electrode 1a is joined to the collector 4a, and the polarizable electrode 1b is joined to the collector 4b respectively by use of a conductive adhesive layer.

The frame body 3 is formed by laminating multiple layers 3a, 3b, and 3f, which are made of ceramics.

Terminals 6a, 6c, and 6d and a temperature sensor 8 are disposed between the ceramic layers 3e and 3f and inside the layers thereof, and are buried inside the frame body 3 by sintering the frame body 3.

More precisely, the ceramic layer 3e is made of a thin film including the terminal 6a, which is printed on the surface thereof and the ceramic layer 3f is made of a thin film including the terminal 6c, the temperature sensor 8, and the terminal 6d, which are printed on the surface of the ceramic layer 3f.

The terminal 6a is made of metal buried in a via hole, which penetrates the ceramic layer 3e and the ceramic layer 3f. One end of the terminal 6a is formed on a top surface of the ceramic layer 3e, and the other end is formed on a bottom surface of the ceramic layer 3f. The end formed on the top surface of the ceramic layer 3e is connected to the collector 4a.

The terminal 6c is made of metal buried in a via hole, which penetrates the ceramic layer 3f. One end of the terminal 6c is formed on a top surface of the ceramic layer 3f, and the other end is formed on the bottom surface of the ceramic layer 3f. The end of the terminal 6c, which is formed on the top surface of the ceramic layer 3f, is connected to one end of the temperature sensor 8.

The terminal 6d is made of metal buried in a via hole, which penetrates the ceramic layer 3f as similar to the terminal 6c. One end of the terminal 6d is formed on the top surface of the ceramic layer 3f, and the other end is formed on the bottom surface of the ceramic layer 3f. The end of the terminal 6d, which is formed on the top surface of the ceramic layer 3f, is connected to another end of the temperature sensor 8, which is different from the end connected to the terminal 6c.

The collector 4a is electrically connected to the terminal 6a, which is buried in the frame body 3, and the temperature sensor 8 is electrically connected to the terminal 6c and the terminal 6d. Meanwhile, the collector 4b penetrates a wall surface of the frame body 3, and is electrical connected to a terminal 6b which extends on an outer bottom surface of the frame body 3.

The polarizable electrodes 1a and 1b, the separator 2, the collectors 4a and 4b, the sealing plate 5, and the conductive adhesive layers are similar to those in the first embodiment. Accordingly, explanations thereof are omitted.

In addition to the ceramics, a mixture of a ceramic and glass can be used for the ceramic layers 3a, 3b, . . . , and 3f. By using the mixture of the ceramic and the glass, it is possible to lower a sintering temperature of the frame body 3.

Although FIG. 4 illustrates the structure configured to bury the terminals 6a, 6c, and 6d and the temperature sensor 8 inside the frame body 3, the sealing plate 5 may be formed of a laminated ceramic, and the terminals and the temperature sensor may be buried inside the sealing plate 5.

(Operations and Effects)

According to the electrochemical device of the second embodiment, the frame body 3 is formed by laminating multiple layers made of ceramics, and the electronic devices, such as the temperature sensor 8, are disposed between the surfaces of the ceramic layers and inside the ceramic layers, and can be buried inside the frame body 3 by sintering the frame body 3. Moreover, according to this electrochemical device, the electronic device can be formed as the thin film by use of the screen printing method. Accordingly, the electronic device can be buried easily in the frame body 3.

Other Embodiments

Although the present invention has been described with reference to the above embodiment, it is to be understood that the description and the drawings constituting parts of this disclosure shall not limit the scope of the invention. From the teachings of this disclosure, various alternative embodiments, examples, and application techniques are clear to those skilled in the art.

For example, the electrochemical devices according to the above-described embodiments have been explained by taking the electric double layer capacitor as an example. However, the present invention is not limited to the foregoing. The present invention is applicable, in a similar manner to that of the forgoing, to a thin profile battery, such as a lithium battery and a polyacene battery, which is configured of a concave container and a sealing plate. Note that the material of such a device is not particularly limited, and the device can be fabricated by use of various publicly-known materials.

It is therefore needless to say that the present invention includes various other embodiments which are not described herein. Accordingly, the technical scope of the present invention is to be determined with only matters to define the invention as recited in appropriate claims on the basis of the foregoing descriptions.

EXAMPLES

Hereinafter, the electric double layer capacitor according to the present invention will be described more concretely with reference to certain examples. Note that the electric double layer capacitor according to the present invention shall not be limited to the following examples, and that various modifications and alteration can be made as appropriate without departing from the spirit and scope of the present invention.

Example 1

In Example 1, the polarizable electrodes 1a and 1b are fabricated, and concurrently, the electrolytic solution is prepared to produce an electric double layer capacitor as shown in FIG. 1.

[Fabrication of Polarizable Electrodes]

The polarizable electrodes 1a and 1b in a square shape having a side of 3.8 mm and a thickness of 0.5 mm are formed by adding 5 wt % of acetylene black and 5 wt % of polytetrafluoroethylene (PTFE) to activated carbon powder having a specific surface area of 2000 m²/g, and by kneading these materials.

[Preparation of Electrolytic Solution]

An electrolytic solution is prepared by dissolving (C₂H₅)₄NBF₄, which is a solute, into a propylene carbonate as a solvent to achieve a concentration of 1 mol/l.

[Production of Electric Double Layer Capacitor Cell]

The two polarizable electrodes 1a and 1b fabricated as described above are disposed so as to face each other while interposing the separator 2 made of glass fibers therebetween. This group of electrodes is housed in the frame body 3 having a side of 5 mm and a height of 1.6 mm. The frame body 3 is provided in advance with the collector 4a made by plating, which is formed on the bottom surface of the frame body 3. Then, the electrolytic solution in the same amount as the volume of the electrodes is poured into the frame body 3 so as to be impregnated sufficiently into the electrodes. Thereafter, the sealing plate 5, which is made of a liquid crystal polymer and provided with the collector 4 formed by plating in a portion contacting the polarizable electrode 1b, is sealed by ultrasonic welding to obtain the electric double layer capacitor.

Here, the frame body 3 is made of a liquid crystal polymer having the melting point in the range of 270° C. to 400° C. Meanwhile, the terminals 6a and 6c and the protective device 7 are buried inside the frame body 3 by insert molding when fabricating the frame body 3, and are electrically connected in series to the pair of polarizable electrodes 1a and 1b. Moreover, a positive temperature coefficient thermistor (a PTC device) is used as the protective device 7. More precisely, two frames made of stainless steel having a thickness of 0.2 mm and a width of 1.0 mm are used as the terminals 6a and 6c, and insert molding is conducted in the state of fixing both ends of the protective device 7 in a chip shape having a side of 1.0 mm and a thickness of 0.2 mm, to the terminals 6a and 6c either by spot welding or by use of a conductive adhesive. Note that the insert molding process so using the liquid crystal polymer can be achieved almost at the same temperature as that for a general molding process of an electronic device. For this reason, a small-size integrated circuit (IC), such as a thermistor, a transistor, a diode and a varistor, can be used as the electronic device to be buried in the frame body 3.

The electric double layer capacitor fabricated in accordance with the foregoing process has a configuration in which the protective device 7 is buried inside the frame body 3. Compared to the conventional case of adding the protective device 7 to the outside of the frame body 3, therefore, the electric double layer capacitor of the present invention has advantages that it is possible not only to save a mounting surface, but also to increase internal electrical resistance of the protective device 7 rapidly when a temperature rises in the electric double layer capacitor. Accordingly, an electric current on the electric double layer capacitor can be suppressed.

Example 2

In Example 2, an electric double layer capacitor as shown in FIG. 2 is obtained in a similar manner to the above-described Example 1 except that the electronic device to be buried inside the frame body 3 and a method of electrical connection thereof are different.

Specifically, the frame body 3 in Example 2 is made of the liquid crystal polymer resin, and the terminal 6a and the protective device 7 are buried inside the frame body by insert molding in the course of fabricating the frame body 3. In addition, the terminal 6a and the terminal 6b are electrically connected respectively to the collector 4a and the collector 4b, and the protective device 7 is electrically connected in parallel to the pair of polarizable electrodes 1a and 1b. Here, a varistor is used as the protective device 7.

The electric double layer capacitor formed in accordance with the above-described method is able to reduce the internal electrical resistance of the protective device 7 when an excessive voltage is applied to the electric double layer capacitor, and thereby to prevent an excessive current from flowing on the electric double layer capacitor. Particularly, because the protective device 7 is buried inside the frame body 3, an adverse effect of electrostatic surge can be prevented in comparison with a conventional case of adding the protective device 7 to the outside of the frame body 3. Note that a similar effect can be obtained by using a zener diode as the protective device 7.

Example 3

In Example 3, an electric double layer capacitor as shown in FIG. 3 is obtained in a similar manner to the above-described Example 1 except that the electronic device to be buried inside the frame body 3 and a method of electrical connection thereof are different.

Specifically, the frame body 3 in Example 3 is made of the liquid crystal polymer resin, and the terminal 6a, 6c, and 6d and the temperature sensor 8 are buried inside the frame body by insert molding in the course of fabricating the frame body 3. In addition, the terminal 6a and the terminal 6b are electrically connected respectively to the collector 4a and the collector 4b, and the temperature sensor 8 is electrically connected to the terminal 6c and the terminal 6d. Moreover, a thermocouple is used as the temperature sensor 8. Note that the temperature sensor 8 is electrically insulated from the pair of polarizable electrodes 1a and 1b.

Because the temperature sensor 8 is buried inside the fame body 3, the electric double layer capacitor formed in accordance with the above-described method is capable of accurately following and measuring temperature variation in the electric double layer capacitor in comparison with the conventional case of adding a temperature savor to the outside of a frame body. Note that a similar effect can be obtained by using a thermistor or a resistance thermometer bulb as the temperature sensor 8.

Example 4

In Example 4, an electric double layer capacitor as shown in FIG. 4 is obtained by forming the frame body 3 of laminated ceramics.

Specifically, the frame body 3 in Example 4 includes 6 sheets of laminated ceramic layers (ceramic green sheets) 3a, 3b, . . . , and 3f. The outline of each ceramic green sheet is formed into a square having a side of 5 nm.

The ceramic layer 3c is the ceramic green sheet, which is provided with a predetermined pattern constituting part of the terminal 6a formed on the surface of the ceramic layer 3e, in accordance with the screen printing method. Moreover, the ceramic layer 3e includes one via hole penetrating therethrough, and metal constituting part of the terminal 6a is buried in the via hole.

The ceramic layer 3f is the ceramic green sheet, which is provided with a predetermined pattern constituting part of the terminal 6c and of the terminal 6d, as well as the temperature sensor 8 formed on the surface of the ceramic layer 3f, in accordance with the screen printing method. Moreover, the ceramic layer 3f includes two via holes penetrating therethrough, and metal constituting part of the terminal 6c and the terminal 6d is buried inside each of the two via holes.

Then, the 6 sheets of the ceramic layers 3a, 3b, . . . , and 3f are laminated and pressed together, and then fired in a nitrogen atmosphere to obtain a structure similar to that of Example 3, which is configured to bury the terminals 6a, 6c, and 6d and the temperature sensor 8 inside the frame body 3.

More precisely, the terminal 6a is made of the metal buried in the via hole, which penetrates the ceramic layer 3e and the ceramic layer 3f. One end thereof is formed on the top surface of the ceramic layer 3e, and the other end is formed on the bottom surface of the ceramic layer 3f. The end formed on the top surface of the ceramic layer 3e is connected to the collector 4a.

The terminal 6c is made of the metal buried in the via hole, which penetrates the ceramic layer 3f. One end thereof is formed on the top surface of the ceramic layer 3f and the other end is formed on the bottom surface of the ceramic layer 3f. The end of the terminal 6c formed on the top surface of the ceramic layer 3f is connected to one end of the temperature sensor 8.

The terminal 6d is made of the metal buried in the via hole, which penetrates the ceramic layer 3f as similar to the terminal 6c. One end thereof is formed on the top surface of the ceramic layer 3f, and the other end is formed on the bottom surface of the ceramic layer 3f. The end of the terminal 6d formed on the top surface of the ceramic layer 3e is connected to the other end of the temperature sensor 8, which is different from the end thereof connected to the terminal 6c.

Meanwhile, the temperature sensor 8 is formed as a pattern having a thickness of 1 μm, a width of 50 μm, and a length of 1 mm on the ceramic green sheet by use of paste containing metal or an oxide thereof. As for the paste, a material containing metal, such as Pt, Pd or W or a metal oxide thereof, is used for forming the ceramic layers 3a, 3b, . . . , and 3f as a high-temperature sintering ceramic (having a sintering temperature equal to or above 1000° C.), and a material containing metal, such as Au or Cu or a metal oxide thereof is used for forming the ceramic layers 3a, 3b, . . . , and 3f as a low-temperature sintering ceramic (having a sintering temperature in a range from 900° C. to 1000° C.). In addition, a surface of the temperature sensor 8 can be covered with alumina paste in order to prevent diffusion during a sintering process. Note that a mixture of alumina and borosilicate glass can be used for the low-temperature sintering ceramic, and alumina can be used or the high-temperature sintering ceramic.

By using the similar method, it is also made possible to fabricate a structure similar to those of Examples 1 and 2, in which the frame body 3 is formed of the laminated ceramics.

Claims

1. An electrochemical device comprising:

a pair of electrodes;

an electrolytic solution; and

a container for housing the pair of electrodes and the electrolytic solution, wherein

the container includes a frame body having concave shape and a sealing plate configured to seal an opening of the frame body, and

an electronic device is buried inside any one of the frame body and the sealing plate.

2. The electrochemical device according to claim 1,

wherein any one of the frame body and the sealing plate where the electronic device is buried, is made of resin.

3. Tho electrochemical device according to claim 1, wherein

the frame body has configuration that a plurality of ceramic layers are laminated, and

the electronic device is disposed between the layers, and buried inside the frame body by sintering the frame body.