JPS6156860B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic device and a method for manufacturing the same, and particularly to a method for enclosing a flat electronic device and taking out an electrode.

In recent years, electronic devices such as calculators and electronic watches have been becoming smaller, especially thinner. Therefore, the electronic elements used in these devices, such as capacitors, semiconductors, and batteries, are also required to be thin and flat products. This type of electronic device is easily deteriorated by gases such as oxygen and nitrogen in the air, and water vapor, so it is necessary to encapsulate the electronic device in an electrical insulator such as glass or synthetic resin to isolate it from the outside air. Conventional encapsulation methods include immersion methods in which electronic devices are immersed in a viscous liquid of synthetic resin such as epoxy and cured by heat, or a hot molten liquid of synthetic resin such as epoxy is encapsulated in a fixed shape of metal containing electronic devices. The so-called mold forming method is mainly used, in which the material is extruded under pressure into a mold, encapsulated, and then thermally cured. The dipping method has the disadvantage that it is difficult to control the thickness of the encapsulated resin to a constant level, and that the thickness varies widely, making it impossible to produce products with a uniform shape. For this reason, electronic elements encapsulated using the dipping method are used for smaller and thinner electronic devices that require stricter shape and dimensions.
It's inappropriate. On the other hand, electronic elements encapsulated using the molding method are molded in a mold with a fixed shape, so electronic elements with constant external dimensions can be obtained.On the other hand, electronic elements encapsulated using the molding method are Electrical characteristics are often significantly degraded by mechanical and thermal stresses such as the pressure of the extruded resin, the heat of the molten resin, and the heat during curing. Further, since the electronic element is molded by pushing resin into a mold, the electronic element contained therein will be exposed from the resin layer even if the dimensional accuracy of the mold for positioning the electronic element is well taken care of. For this reason,
The thickness of the resin enclosed by the molding method is as follows:
It has to be made relatively thick, and as a result, the shape is not sufficiently satisfactory as an electronic element that can be made smaller and thinner. Furthermore, since the structure for drawing out the electrodes from the encapsulated electronic device to the outside becomes complicated, the structure of the mold for molding also becomes complex and highly precise, making it unsuitable for encapsulating electronic devices for mass production.

Among the electronic elements mentioned above, capacitors and
This is a drawback of conventional products related to resistors and semiconductors. Batteries are other electronic devices that are most required to be made smaller and thinner.Next, conventional drawbacks of batteries will be explained in detail with reference to the drawings.

Generally, a battery consists of a negative electrode active material 1 as shown in FIG.
A layered structure in which an electrolyte layer 2 is sandwiched between a positive electrode active material 3 and a positive electrode active material 3 becomes a basic battery component (hereinafter abbreviated as a battery element body 9). Usually, an electrode is formed on this element body 9, and the element body 9 is sealed so that the electrode can be taken out from the outside. Due to the characteristics of the battery, the current value that can be taken out is also affected by the internal resistance of the battery, but if the internal resistance of the battery is the same, it is proportional to the contact area between the positive and negative active materials 3 and 1 and the electrolyte layer 2. and grow bigger. Further, the life of the battery is proportional to the amount of materials included in the product of the positive electrode active material 3 and the negative electrode active material 1. Therefore, in order to provide a battery with a large current value and a long life, the structure must be made into a sheet with a large contact area, or the sheet can be wound. It is desirable to have a battery element in the shape of a flat type, and a flat battery containing the battery element.

BACKGROUND ART Conventionally, as a flat battery, there is a battery usually called a button shape or a coin shape. Although there are differences in the bottom area and thickness of the batteries, they all basically have the structure shown in Figure 1. The battery element body 9 is wrapped in a lid 4 made of negative electrode metal that also serves as an electrode and a case 5 made of positive electrode metal.
is electrically insulated by an electrically insulating packing 6, and the battery 9 element body 9 has a sealed structure. This requires a lid 4 with a special structure, a case 5, and a packing 6. Furthermore, the case 5 is inserted through the packing 6, and a special machining process called caulking is applied to seal the battery element body 9. Due to its complex structure, special parts and processing steps are required. Moreover, in order to increase the contact area between the electrolyte layer 2 and the active materials 1 and 3 of the negative and positive electrodes in order to increase the current value, there is a certain limit with a special structure as shown in Figure 1. Batteries with large values cannot be used. Furthermore, due to the special structure, there is a certain limit to how thin it can be made.

Recently, in order to increase the current value, a sheet-shaped battery with a relatively large area and thinner thickness has been developed. FIGS. 2 and 3 show cross-sectional views of conventional sheet-shaped batteries. FIG. 2 shows a battery structure in which metal foils 7, 7' are electrically insulated from above and below a battery element body 9 via an electrically insulating packing 8. (a) If the upper and lower metal foils 7 and 7' are connected, an electrical short circuit will occur, so in order to enclose the battery element body 9, electrically insulating packing 8
(b) In order to obtain sufficient electrical insulation, the thickness of the packing 8 must be made relatively thick. (c) The manufacturing process is complicated because it is difficult to align the packing 8 with the battery element body 9, and (d) The adhesion between the metal foils 7 and 7' and the packing 8 made of synthetic resin is relatively poor. There are drawbacks such as insufficient sealing.

As an example of another conventional product, as shown in FIG.
As shown in the figure, the packing 8 is no longer necessary and the adhesion is improved. On the other hand, it becomes complicated to take out the positive and negative external electrodes. That is, as shown in FIG. 2, a metal foil 10 of the negative electrode layer is provided in the same way as the metal foil 7 on the upper part of the negative electrode active material layer 1, and a metal foil 11 of the positive electrode layer is provided below the positive electrode active material 3. .
For this reason, (i) the electrical insulating film 1 of the outer case is
The external electrodes cannot be taken out unless 2 and 12' are cut and removed at appropriate locations. (ii) Therefore, the battery becomes thicker by the thickness of the metal foils 10 and 11 of the negative and positive electrode layers. (iii) Due to the weak adhesion between the electrical insulating films 12, 12' and the metal foils 10, 11, there are drawbacks such as insufficient sealing, which makes it impossible to put it into practical use.

An object of the present invention is to eliminate such conventional drawbacks, to provide an electronic device having a thin layer, good sealing properties, and easy removal of external electrodes, and a method for manufacturing the same.

That is, according to the present invention, the upper and lower surfaces of an element body such as a semiconductor, resistor, capacitor, or battery on which electrode portions are formed are made of an anisotropically conductive sheet that is conductive in the thickness direction and electrically insulating in the surface direction. As a result, an electronic device is obtained which is characterized in that the external electrodes are tightly encapsulated and the entire periphery of the device body is sealed to form external electrodes. Furthermore, the element bodies on which electrode parts are formed, such as semiconductors, resistors, capacitors, and batteries, are designed to be conductive in the thickness direction and electrically insulating in the surface direction.
A method for manufacturing an electronic device is obtained, which comprises sandwiching the electronic device between two anisotropically conductive sheets, and then sealing the sheets around the device body.

Next, FIGS. 4 and 5 are cross-sectional views showing specific examples of anisotropically conductive sheets having conductivity in the thickness direction and electrical insulation in the surface direction. Figure 4 shows a conductive thin wire 13 made of metal such as stainless steel or copper, or carbon fiber, made of rubber elastic material such as butadiene rubber or silicone rubber, or polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, nylon, polyimide, etc. Electrically insulating synthetic resins such as plastics14
It is made into a sheet or film by being buried densely in parallel with the thickness direction, and the thin wires 13 are exposed on the surface of the sheet. Therefore, the sheet exhibits electrical insulation in the surface direction, but conductivity in the thickness direction of the sheet. FIG. 5 shows a synthetic resin 1 as described above in which conductive grains 15 in the form of metals such as copper, iron, nickel, and silver or fine particles such as graphite are used.
4 is a cross-sectional view of a sheet or film that is oriented and connected in the thickness direction in FIG. In this case as well, as in FIG. 4, the sheet exhibits conductivity in the thickness direction and electrical insulation in the sheet surface direction. An element body 9 in which no electrode is formed using such an anisotropically conductive sheet
By tightly enclosing and sealing, the element body 9 is sealed and at the same time, the electrode can be easily taken out from an appropriate portion on the sheet surface. Therefore, since the anisotropically conductive electrode sheet is electrically insulating in the plane direction and electrically conductive only in the thickness direction, the element body 9 can be contained in this sheet alone, and the first
As shown in FIGS. 3 to 3, it is also possible to interpose electrically insulating packings 6 and 8, as well as metal foils 10 and 1.
There is no need to cut and remove the exterior electrical insulating films 12, 12' to expose the negative electrode layer and the positive electrode layer. Therefore, the structure of the electronic device is simplified, which is particularly effective in making it smaller and thinner. In addition, since the sealing part of an electronic device is made of the same material as the anisotropically conductive sheets, for example, the sealing part is dissolved with a solvent that dissolves the synthetic resin of the anisotropically conductive sheet, and then the sealing part is sealed under pressure, and the solvent is evaporated. The sealing methods are relatively simple, including thermally melting and pressure welding, and sealing with adhesive, and the sealing performance of the sealing part is also extremely good compared to conventional methods. becomes.

Furthermore, in the present invention, since the electrode parts 19 and 19' are already formed on the element body 9, a part of the anisotropically conductive sheet is
By simply bringing the external electrodes into close contact with 9', the external electrodes can be taken out independently and easily and reliably.

Embodiments of the present invention will be described in detail below with reference to the drawings.

Example 1 A sheet of lithium metal was cut into disks with a diameter of 30 mm and a thickness of 0.3 mm under an argon gas atmosphere. This lithium metal disk is used as the negative electrode active material 1 of the battery, and is crimped onto a stainless steel electrode part 19 having a diameter of 30 mm and a thickness of 50 μm, which will serve as the negative electrode. Next, on the negative electrode active material 1, an electrolyte layer 2 made of polypropylene non-woven fabric with a diameter of 31 mm and a thickness of 100 μm, which has been soaked in a propylene carbonate solution of lithium perchlorate, is placed, and on top of that, 95 weight of manganese dioxide powder is placed. %
A positive electrode active material 3 formed into a disc shape of 30 mm in diameter and 0.3 mm in thickness by pressure molding a mixed powder of 5% by weight of carbon black powder and 5% by weight of carbon black powder is placed on top of the positive electrode active material 3, which will become the positive electrode. A 50 μm stainless steel electrode portion 19' was crimped to obtain a battery element body 9.
FIG. 6a shows the battery element body 9 obtained as described above. As shown in Fig. 4, stainless steel thin wires 13 with a diameter of 30 μm connect anisotropically conductive sheets 16 and 16' with a thickness of 0.3 mm embedded in a polyethylene synthetic resin 14 at intervals of 0.3 mm, respectively.
Figure 6b
It is brought into close contact with the upper and lower surfaces of the element body 9 as shown in FIG. This was placed on a Teflon-coated metal plate (not shown), and a cylindrical press jig with a diameter of 40 mm in which a groove of 31 mm in diameter and 3 mm in depth was dug, which had been heated above the melting point of polyethylene at a temperature of 150°C or above, was placed on it. Pressure is applied with a tool (not shown) to fuse the peripheral parts 16a, 16b of the anisotropically conductive sheet that covers the side circumference of the element body 9, thereby fixing the element body 9 to the peripheral parts 16a, 16b of the anisotropically conductive sheet.
It was sealed with. Figures 6c and 6d are a perspective view and a sectional view, respectively, of the battery obtained as described above. Anisotropic conductive sheets 16a, 16b
In this case, the sealing portion 18 is located on the positive electrode side on the lower surface of the element body 9.

When the terminals of a voltmeter were connected to the thin wires 13 of the anisotropic conductive sheet exposed on the upper and lower surfaces of the battery thus obtained, and the electromotive force of the battery was measured, the initial voltage value was 3.5V. As a result of voltage measurement with a load resistance of 1 kΩ, it maintained 3.0 V for a long time, showing good battery characteristics. Further, even when this battery was left in high humidity for a long time, no moisture was observed to enter the battery, and very good sealing performance was exhibited.

Example 2 Electrode portions 19 and 19' of a capacitor element body 20 were formed with silver-based conductive paste on the top and bottom surfaces of a ceramic dielectric 17 measuring 10 mm long, 7 mm wide, and 0.5 mm thick, respectively. Anisotropic conductive sheets 16 and 16' similar to those in Example 1, measuring 12 mm long, 9 mm wide, and 0.1 mm thick, are closely attached to the upper and lower surfaces of 19', and this is formed into a groove of 11 mm long, 8 mm wide, and 0.25 mm deep. Place it on a Teflon-coated metal plate (not shown) with a hole in it, and place it on a Teflon-coated metal plate (not shown) with a groove of 11 mm in length, 8 mm in width, and 3 mm in depth cut from the top. Pressure was applied using a metal prism (not shown) coated with heated Teflon.

FIG. 7 is a sectional view of the capacitor thus obtained. Anisotropic conductive sheets 16 and 1
Sealing portion 18 of peripheral portions 16a and 16b of 6′
Unlike the first embodiment in which the sealing portion 18 is tilted to one side, the sealing portion 18 is located at the center of the element body 20 in the thickness direction. Thin wires 1 of the anisotropic conductive sheets 16 and 16' exposed on the upper and lower surfaces of this capacitor
As a result of measuring the capacitance value and dielectric loss tan δ at a frequency of 1 kHz by connecting measurement terminals (not shown) to 3 and 3, respectively, the values of the capacitor element 20 before being enclosed in the anisotropic conductive sheets 16 and 16' are shown. There was no immediate change. Furthermore, even in a humidity test in which this capacitor was left in a high-humidity atmosphere for a long time, the characteristics of the capacitor did not change at all from before the capacitor was left in a humid environment.

Example 3 FIG. 8 is a top view of a total of 12 battery element bodies 9 obtained by the same method as in Example 1. First, the vertical 118 cm was placed on a Teflon plate (not shown).
The same anisotropic conductive sheet as in the embodiment with a size of 155 mm and a width of
Arranged at intervals of 7.0mm each. Next, a total of 12 cylindrical grooves with a diameter of 30.3 mm and a depth of 3 mm were dug, 3 vertically and 4 horizontally, with a length of 140 mm, a width of 170 mm, and a height of 10 mm. The element body 9 was heated and pressurized from above using a heated rectangular parallelepiped metal jig (not shown). Anisotropic conductive sheet 1
After the sealing parts 18 of 6 and 16' are sufficiently fused, the rectangular parallelepiped metal jig is removed from the element body 9, and then each battery is punched out using a cutter with an inner diameter of 32 mm, and sealed with an anisotropic conductive sheet. Obtained 12 batteries. When the characteristics of this battery were measured with a load resistance of 1 kΩ, it showed a voltage of 3 V as in Example 1.
In addition, all sealing properties were good.

As described above, according to the present invention, it is possible to mass-produce small and thin electronic devices by simultaneously performing the external sealing and the electrode extraction. Note that the present invention is not limited to the batteries and capacitors described in the embodiments, but can also be applied to other general electronic devices such as semiconductors and resistors. Moreover, it goes without saying that the shape of the electronic element can be applied to any shape other than the present embodiment, such as a disk shape or a rectangular parallelepiped, as necessary.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional button-shaped or coin-shaped battery, and FIGS. 2 and 3 are sectional views of conventional sheet-shaped batteries. FIGS. 4 and 5 are cross-sectional views of anisotropically conductive sheets used in the present invention. Fig. 6 is an assembled view of a battery according to an embodiment of the present invention, Fig. 6a is a perspective view of a battery element body, and Fig. 6b is an assembled view of an anisotropic conductive sheet and a battery element body. FIG. 6c is a perspective view of the battery after the element body is sealed, and FIG. 6d is a sectional view of FIG. 6c. FIG. 7 is a sectional view of a capacitor according to another embodiment of the present invention. FIG. 8 is a top view of a mass-produced battery in which the battery of the present invention is formed into a disk shape. 1... Negative electrode active material, 2... Electrolyte layer, 3... Positive electrode active material, 4... Lid (made of negative electrode metal), 5...
Case (made of positive electrode metal), 6, 8... Electric insulating packing, 7, 7', 10, 11... Metal foil, 9... (Battery) element body, 12, 12'...
Electrical insulating film, 13... (conductive) thin wire,
14...Synthetic resin, 15...(conductive) particles,
16... Anisotropically conductive sheet, 17... Ceramic dielectric, 18... (Anisotropically conductive sheet 16a, 1
6b) sealing part, 16a, 16b... peripheral part of the anisotropic conductive sheet, 19, 19'... (of the element body)
Electrode part, 20... (capacitor) element body.

Claims (1)

[Scope of Claims] 1. Devices having electrode parts formed on opposing upper and lower surfaces of the element body, such as semiconductors, resistors, capacitors, and batteries, which exhibit conductivity in the thickness direction and have electrical insulation properties in the plane direction. What is claimed is: 1. An electronic device characterized in that the electronic device is closely encapsulated by a conductive sheet, and the entire periphery of the device body is sealed to form external electrodes. 2. A step of forming electrode parts on the upper and lower opposing surfaces of an element body such as a semiconductor, a resistor, a capacitor, and a battery, and forming the element body into two anisotropically conductive sheets having conductivity in the thickness direction and electrical insulation in the surface direction. 1. A method for manufacturing an electronic device, comprising the step of sandwiching the sheet in a flexible sheet, and then sealing the sheet around the device body.