JPS6156861B2 - - 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, resistors, 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 processed into a mold, extruded, 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 by the immersion method are not suitable for use in smaller and thinner electronic devices that require stricter dimensions. On the other hand, electronic elements encapsulated using the molding method are molded in a mold with a fixed shape, so an electronic element with constant external dimensions can be obtained. In many cases, the electrical characteristics are significantly deteriorated due to mechanical and thermal stress such as the pressure of the resin that is extruded under pressure, the heat of the molten resin, and the heat during curing. Further, since the electronic element is molded by pushing resin into the mold, the electronic element contained within the resin layer is exposed from the resin layer even if the positioning of the electronic element and the dimensional accuracy of the mold are well taken care of. For this reason, the thickness of the resin encapsulated using the molding method has to be relatively thick.
In the end, the shape of the electronic device is not sufficiently satisfactory as an electronic device that can be made smaller and thinner. Furthermore, since the structure for drawing out the electrodes from the encapsulated electronic element to the outside becomes complicated, the structure of the mold for molding also becomes complex and highly precise, making it unsuitable for encapsulating electronic elements that are mass-produced at low cost. .

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.
The layered structure in which the electrolyte layer 2 is sandwiched between the positive electrode active material 3 and the positive electrode active material 3 becomes a basic battery component (hereinafter abbreviated as the element body 9). Normally, due to the characteristics of a battery, in which electrodes are formed on the element body 9 and the element body 9 is sealed so that the electrodes can be taken out from the outside, the current value that can be taken out is also affected by the internal resistance of the battery. However, when the internal resistance of the battery is the same, it increases in proportion to the contact area between the positive and negative electrode active materials 3 and 1 and the electrolyte layer 2. In addition, the battery life depends on the positive electrode active material 3
and is proportional to the amount of material included in the negative electrode active material 1 product. Therefore, in order to design 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, but this is difficult in terms of thinning. A flat battery containing a sheet-shaped battery element is desirable.

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 element body 9 is sealed. This requires a specially constructed lid 4, case 5, and packing 6, and the case 5 is sealed through the packing 6 by a special machining process usually called caulking. 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 FIG. Batteries with large current 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. A cross-sectional view of the conventional sheet-shaped battery of FIGS. 2 and 3 is shown. FIG. 2 shows a battery in which the upper and lower sides of a battery element body 9 are covered with electrode layers of metal foils 7 and 7', and the metal foils 7 and 7' are electrically insulated via electrically insulating packing 8. It's in the structure. This is because (a) an electrical short circuit occurs when the upper and lower metal foils 7 and 7' are connected, so electrically insulating packing 8 is required to enclose the battery element 9, and (b) sufficient electrical insulation is required. (3) The manufacturing process is complicated because it is difficult to align the packing 8 with the battery element body 9, and (d) The packing 8 must be relatively thick. There are drawbacks such as relatively poor adhesion between the foils 7, 7' and the packing 8 made of synthetic resin, resulting in 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 negative electrode metal foil 10 is provided in the same way as the metal foil 7 above the negative electrode active material 1, and a positive electrode metal foil 11 is provided below the positive electrode active material 3. For this reason, (i) the external electrode cannot be taken out unless the electrical insulating films 12 and 12' on the exterior casing are cut and removed at appropriate locations so that both electrode layers made of metal foils 10 and 11 are exposed to the outside of the battery. . (ii) Therefore, the battery becomes thicker by the thickness of the metal foils 10 and 11 of the negative and positive electrode layers. (iii) Electrical insulation film 1
The adhesiveness between the metal foils 10 and 11 and the metal foils 10 and 11 is weak, resulting in drawbacks such as insufficient sealing, which makes it impossible to put it into practical use.

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

According to the present invention, an anisotropic conductive sheet that exhibits conductivity in the thickness direction of the sheet and has electrical insulation properties in the surface direction of the sheet can be used to connect the upper and lower surfaces of element bodies such as semiconductors, resistors, capacitors, and batteries. An electronic device is obtained in which one surface in the thickness direction is continuously and closely enclosed, and the entire periphery of the device body is sealed to form external electrodes.

Furthermore, elements such as semiconductors, resistors, capacitors, and batteries are held by folding a single anisotropically conductive sheet that is conductive in the thickness direction and electrically insulating in the sheet surface direction. , a method for manufacturing an electronic device is obtained, which is characterized by sealing a sheet 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. FIG. 4 shows a conductive thin wire 13 made of a metal such as stainless steel or steel, or a conductive thin wire 13 such as carbon fiber, made of a rubber elastic material such as butadiene rubber or silicone rubber, or made of polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, nylon, etc. It is made into a sheet or film by embedding it in parallel and densely in the thickness direction in an electrically insulating synthetic resin 14 such as plastic such as polyimide.
A conductive thin wire 13 is exposed on this sheet surface.
Therefore, the sheet exhibits electrical insulation in the surface direction, but conductivity in the thickness direction of the sheet. Fifth
The figure shows a cross section of a sheet (or film) in which conductive grains 15 of metals such as copper, iron, nickel, and silver or fine particles such as graphite are oriented and connected in the thickness direction in a synthetic resin 14 as described above. It is a diagram. 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. When the element body 9 on which no electrode is formed is tightly enclosed in such an anisotropic conductive sheet and sealed, the element body 9 is sealed and at the same time, the electrode can be easily removed from an appropriate part on the sheet surface. It can be taken out. Therefore, since the anisotropically conductive sheet is electrically insulating in the surface direction and electrically conductive only in the thickness direction, the element body 9 can be contained within this sheet alone, and as shown in FIG. ~As shown in Figure 3,
The electrically insulating packings 6 and 8 may be interposed, and the electrically insulating films 12 and 12' on the outer packaging may be cut and removed to expose the negative electrode layer and the positive electrode layer of the metal foils 7, 7', 10, and 11. There is no need for any other means to do so. 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 method is relatively simple, such as thermally melting and pressure welding, or 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, as shown in FIGS. 6a to 6d,
Since a single anisotropically conductive sheet is folded to sandwich the element body 9 and sealed, the number of sealed portions 18 is reduced, resulting in a relatively simple shape. It also has excellent sealing properties. Furthermore, by placing a large number of element bodies 9 on the sheet surface, folding the anisotropic conductive sheet, and sealing the periphery of the element bodies at once, it is possible to mass-produce a large number of electronic elements and form an external utility pole at the same time as sealing. method is obtained. Embodiments of the present invention will be described in detail below with reference to the drawings.

Example 1 A lithium metal sheet was cut into a rectangular parallelepiped with a length of 15 mm, a width of 30 mm, and a thickness of 0.3 mm under an argon gas atmosphere. This lithium metal plate is used as the negative electrode active material 1, and this becomes the negative electrode with a length of 15 mm, width of 30 mm, and thickness of 50 μm.
The electrode section 19 made of stainless steel is crimped. Next, the negative electrode active material 1 was pre-soaked with a propylene carbonate solution of lithium perchlorate.
An electrolyte layer 2 made of polypropylene non-woven fabric 30.5 mm long and 100 μm thick is placed on top of it, and a mixed powder of 95% by weight manganese dioxide powder and 5% by weight carbon black powder is pressure molded to form a fabric with a length of 15 mm, a width of 30 mm, and a thickness of 0.3 mm.
Place the cathode active material 3 formed into a rectangular parallelepiped with a length of 15 mm, a width of 30 mm, and a thickness of 30 mm.
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 Figure 4, a thin stainless steel wire 13 with a diameter of 30 μm is
Anisotropically conductive sheets 16 with a thickness of 0.3 mm are embedded in a polyethylene synthetic resin 14 at intervals of 19 mm.
It is cut into a rectangle with a width of 64 mm and a width of 64 mm, and the lower surface of the element body 9 is brought into close contact with the lower surface of the element body 9 as shown in FIG. 6b. Next, as shown in FIGS. 6b and 6c, the anisotropically conductive sheet 16 is folded to bring the anisotropically conductive sheet 16 into close contact with the upper surface of the element body 9. In this state, place it on a Teflon plate (not shown), and place it on a 20 mm long, 40 mm wide, 10 mm thick plate with a groove of 15.5 mm long, 30.5 mm wide, and 3 mm deep, which has been heated above the melting point of polyethylene. The peripheral parts 16a and 16b of the anisotropically conductive sheet that covers the side periphery of the element body 9 are pressurized with a prismatic press jig (not shown).
were fused to seal the element body 9 with the peripheral parts 16a and 16b of the anisotropically conductive sheet. Figure 6 d and e
2A and 2B are a perspective view and a cross-sectional view, respectively, of the battery obtained as described above. Anisotropic conductive sheet 16
In this case, the sealing portion 18 of a, 16b is the element body 9
It is located on the positive electrode side on the bottom surface of the .

The electromotive force of the battery was measured by connecting the terminals of a voltmeter to the thin wires 13 of the anisotropically conductive sheet exposed on the top and bottom surfaces of the battery thus obtained.
It showed an initial voltage value of 3.5V, and as a result of voltage measurement with a load resistance of 1kΩ, it maintained 3.0V 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 portion 19' of a capacitor element body 20 in which electrode portions 19 and 19' were formed with silver-based conductive paste on the upper and lower surfaces of a ceramic dielectric 17 measuring 10 mm long, 7 mm wide, and 0.5 mm thick, respectively. 13mm long and 18mm wide on the bottom of the
The anisotropically conductive sheet 16 with a thickness of 0.3 mm and a thickness of 0.3 mm was brought into close contact with the anisotropic conductive sheet
6 was folded and brought into close contact with the upper surface of the element body 9. This was placed on a Teflon-coated metal plate (not shown) in which a groove of 11 mm in length, 8 mm in width, and 0.30 mm in depth was dug, and a groove of 11 mm in length, 8 mm in width, and 3 mm in depth was dug from the top. The peripheral portions 16a and 16b of the anisotropically conductive sheet 16 are fused together by applying pressure with a metal prism (not shown) coated with Teflon, which has been heated above the melting point of polyethylene and has a length of 15 mm and a width of 15 mm. The body 9 was sealed with an anisotropic conductive sheet 16.

FIG. 7 is a sectional view of the capacitor thus obtained. The sealing portions 18 of the peripheral portions 16a and 16b of the anisotropic conductive sheet 16 are located at the central portion of the element body 20 in the thickness direction (unlike the shape in which the sealing portions 18 are tilted to one side as in Example 1). I'm coming. The capacitance value and dielectric loss (tan
As a result of measuring δ), the value was not significantly different from the value of the capacitor element body 20 before being enclosed in an anisotropic conductive sheet. Furthermore, as a result of conducting a moisture resistance test on this capacitor, the capacitor characteristics were completely unchanged from before the test.

Example 3 FIG. 8 shows a total of eight battery element bodies 9 obtained by the same method as in Example 1, placed in a state as shown in FIG. 6c using one anisotropically conductive sheet. FIG. The element bodies 9 are arranged at intervals of 5 mm. This is vertical 15.5
A preheated rectangular parallelepiped metal jig (not shown) measuring 180 mm long, 35 mm wide, and 10 mm thick has grooves of 30.5 mm wide and 3 mm deep dug at 4 mm intervals.
Heat and pressure was applied from above. Anisotropic conductive sheet 16
After the sealed portion 18 is sufficiently fused, the rectangular parallelepiped metal jig is removed from the element body 9, and then the sealed portion 18 is cut and sealed with an anisotropic conductive sheet measuring 17 mm long and 32 mm wide. A total of 8 batteries were obtained. When the voltage of each of these batteries was measured with a load resistance of 1 kΩ, the voltage was 3.0 V as in Example 1, and the sealing properties were all 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. Furthermore, 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 semicircular plate as shown in FIG. 9, if necessary. Furthermore, the present invention is applied to the element body of an electronic element enclosed by an anisotropic conductive sheet, regardless of whether an electrode part is not formed in advance or an electrode part is formed in the element body. be able to.

[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 a conventional sheet-shaped battery. FIGS. 4 and 5 are cross-sectional views of anisotropically conductive sheets used in the present invention. 6th
The figures are assembly diagrams 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 a battery element body closely placed on an anisotropic conductive sheet and folded. FIG. 6c is a perspective view of the anisotropically conductive sheet folded and the element body is clamped, FIG. 6d is a perspective view of the element body after it is sealed, and FIG. FIG. 6 is a cross-sectional view of FIG. 6d; 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 shape of the present invention is formed into a rectangular parallelepiped, and FIG. 9 is an electronic element of the present invention. FIG. 2 is a perspective view of an electronic element formed into a semicircular plate 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 layer, 15... (conductive) particles, 16, 16'... Anisotropic conductive sheet, 16
a, 16b... Peripheral part of anisotropic conductive sheet, 17
... Ceramic dielectric material, 18 ... Sealing portion (of anisotropically conductive sheets 16a, 16b), 19, 19'
...Electrode portion (of the element body), 20...Element body (of the capacitor).

Claims (1)

[Claims] 1. Element bodies such as semiconductors, resistors, capacitors, and batteries can be connected to the upper and lower surfaces by an anisotropically conductive sheet that is conductive in the thickness direction of the sheet and electrically insulating in the surface direction of the sheet. 1. An electronic device characterized in that one surface in the thickness direction is continuously and tightly enclosed, and the entire periphery of the device body is sealed to form an external electrode. 2. Element bodies such as semiconductors, resistors, capacitors, and batteries are held by folding a single anisotropically conductive sheet that is conductive in the thickness direction and electrically insulating in the surface direction of the sheet, and then A method for manufacturing an electronic device, comprising sealing the sheet around the device body.