JPS607056A - Manufacture of flexible thin battery - Google Patents

Abstract

PURPOSE:To obtain a flexible thin battery having a complete sealing performance and in which no cracks or gaps are caused by folding or the like by performing ultraviolet-ray irradiation treatment on the inner areas of the sealing portions of flexible exterior members before sealing is performed by adhesion or heating. CONSTITUTION:Ultraviolet rays are irradiated on sealing areas 7a and 8a formed on the inner facing surfaces of the sealing portions of flexible exterior members 7 and 8 for a battery. Next, after an adhesive 9 is applied to the sealing areas 7a and 8a, adhesional sealing is performed or fusional sealing is performed through ultraviolet wave welder, high frequency electric field or something similar. After such ultraviolet ray irradiation, any dust or foreign substance does not adhere to the sealing areas 7a and 8a and decreased numbers of minute capillary vessels and gaps are developed thereby enabling liquid leakage to be suppressed. Besides, no liquid leakage is caused even when the battery is folded repeatedly. Accordingly a flexible thin battery having an excellent durability can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a flexible thin battery with improved sealing of an exterior member.

Conventionally, batteries in which power generating elements are encapsulated in a polymer film are known as paper batteries, sheet batteries, etc., but it has not been possible to maintain stable battery performance even after repeated bending and deformation. Therefore, careful handling was required. Therefore, flexible thin batteries that can withstand flexible bending, curving, and deformation and are thinner and have a wider area are being considered.

However, among such flexible thin batteries, many chemical batteries such as manganese batteries, mercury batteries, silver oxide batteries, and lithium batteries use various inorganic electrolytes or organic solvents such as acidic, neutral, and alkaline. Although the power generating element contains an organic electrolyte in which salt is dissolved in the flexible exterior member, minute capillaries and gaps are likely to occur after adhesion or welding during the sealing process of the flexible exterior member, and it is difficult to completely seal it. Even if it is sealed, as it is repeatedly bent and curved, capillary tubes and gaps will form, causing leakage and internal shortening.
This was a step forward in terms of reliability as a thin, flexible battery. In addition, in physical batteries such as solar cells and photovoltaic cells that use amorphous silicon, cadmium sulfide, selenium, etc. as power generating elements, flexible exterior members are superior in light transmittance, light resistance, and heat resistance. Although these are added as conditions for selection, there are very few that almost satisfy all of the conditions, and most of them are difficult to adhere to, making sealing difficult.

The problem with sealing strength and airtightness is that the environmental resistance such as moisture resistance and heat resistance, which are essentially required for batteries mainly used in outdoor environments, is not sufficient, making them difficult to put into practical use. There was a desire for improved quality.

The present invention has been made in view of the above circumstances, and includes applying ultraviolet irradiation treatment to the inward surface of the sealing portion of a flexible exterior member enclosing a power generation element in advance, and then sealing with adhesive or heating. The object of the present invention is to obtain a flexible thin battery having perfect sealing and adhesive strength that does not cause cracks or gaps even when bent or bent.

Hereinafter, the present invention will be explained in detail based on examples.

(Example 1) FIG. 1(a) is a plan view showing an example of a flexible thin battery manufactured according to the present invention, and FIG. 1(b) is a longitudinal cross-sectional view taken along line I-II in (a). be.

Reference numeral 1 denotes a separator, which holds an electrolytic solution holding member 2, a cathode active material layer 3, and an anode active material layer 4 in a laminated manner. For the separator 1, a flexible polymer film such as cellulose or polypropylene is used.

The electrolyte holding member 2 is formed by molding a material with excellent chemical resistance such as polypropylene or vinylon into a cotton-like or cloth-like shape, and uses KOH-based, NaOH-based, NH4Cl-based,
It is impregnated with an inorganic electrolyte such as a ZnCl-based electrolyte or an organic electrolyte whose main solvent is propylene carbonate, dimethoxyethane, etc. Furthermore, it is held between two flexible exterior members 7 and 8 from above and below. Sealing margins 7a and 8a are provided on the inward surfaces of the portions to be sealed on the outer peripheries of the flexible exterior members 7 and 8, and are irradiated with ultraviolet rays in advance. Next, an adhesive 9 is applied to the sealing margins 7a and 8a by screen printing or the like to perform adhesive sealing. In addition, an ultrasonic welder (
20-28KHz, high frequency electric field (40-60MHz),
Welding and sealing may be performed by heat sealing, impulse sealing, or the like. In addition to the method of sandwiching the power generation element from above and below using two flexible polymer films, it is also possible to cover the power generation element with one flexible polymer film and fill the remaining opening. It may be sealed. flexible exterior member 7,
As the material 8, for example, a resin material such as polyethylene, polyester, polycarbonate, polybutylene terephthalate, or polyimide, or a rubber material such as styrene butadiene rubber, chloroprene rubber, nitrile butadiene rubber, fluorine rubber or silicone rubber is used. Examples of the adhesive 9 include resin-based adhesives such as acrylic resin, methacrylic resin, vinyl chloride resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alexithin resin, silicone resin, or butadiene rubber, chloroprene rubber, Rubber adhesives mainly made of isoprene rubber, fluorine rubber, silicone rubber, urethane rubber, ethylene propylene rubber, etc. are used, or resin materials and rubber materials are mixed, or additives such as reinforcing agents are mixed. It may be adjusted to obtain desired flexibility and elasticity. Ultraviolet rays can be irradiated using carbon arc, xenon discharge lamp,
Using high-pressure or low-pressure quartz mercury lamps, hydrogen discharge lamps, etc.,
Irradiate for 5 to 90 minutes from a close distance of ~15 cm. The ultraviolet generator and irradiation conditions used vary depending on the material type, surface condition, sealing area, etc. of the flexible exterior member.
For example, in the case of polyester-based polymer films, appropriate conditions are set, such as using a quartz mercury lamp or hydrogen discharge lamp, which has a peak in a relatively low wavelength range, to promote good sealing.

Dust and foreign matter floating in the atmosphere will no longer adhere to the surfaces of the sealing margins 7a and 8a after irradiation with ultraviolet rays, and minute capillaries and gaps after sealing will be significantly reduced, which will further suppress leakage in particular. became possible. Various types of polymer film exterior members with a thickness of 200 μm were prepared, and a quartz mercury lamp with a peak wavelength of 2537 cm was used to irradiate ultraviolet light for 40 minutes from a distance of 5 cm.
Adhesive A consisting of 100 parts by weight of epoxy resin (Araldite AW106) and 50 parts by weight of polyamine (Araldite HY956), and Adhesive B consisting of silicone resin (“RTVX32-405” manufactured by Shin-Etsu Silicone Co., Ltd.)
The width of the adhesive part is 25.4 mm and the length is 152.4 mm.
Table 1 shows the results of a peel test at a peel rate of 50 mm/min and an angle of 180°.

As a comparative example, a sample that was not subjected to any ultraviolet treatment was used.

By manufacturing as described above, there is no leakage even after long-term storage, no leakage even after repeated bending and deformation, the power generation element is protected from the external environment, and it has excellent durability and reliability. It has now become possible to provide a highly flexible thin battery. In addition, by adding simple ultraviolet irradiation to the sealing process, which conventionally required strict control, the entire sealing process is simplified, making it possible to achieve stable mass production with high quality and low defect rates. Summer.

(Example 2) FIG. 2(a) is a plan view showing another example of the flexible thin battery manufactured according to the present invention, and FIG.
It is a longitudinal cross-sectional view of the IV line part.

10 is a transparent flexible polymer film, and any film may be used as long as it has excellent light transmittance, processability, heat resistance, and chemical resistance, such as polyethylene, polyester, polypropylene, polycarbonate, polyether ester, polycarbonate, etc. Acetylacetonate, polymethacrylic acid, polyacrylic acid, polyimide, or a synthetic material thereof is prepared and molded to a uniform thickness. A transparent conductive film 11 made of tin oxide, indium oxide, indium tin oxide, or the like is closely attached to the inward surface of the flexible polymer film 10 by vacuum deposition or sputtering glow discharge, and a P-type amorphous film is deposited on the transparent conductive film 11 . The silicon layer 12 has a density of about 50 to 150 cm, and the non-doped impurity amorphous silicon layer 13 has a density of 3000 to 500 cm.
0 ■, the n-type amorphous silicon layer 14 is about 400 ~
Approximately 800 square meters are sequentially formed in a laminated form by the plasma CVD method. Furthermore, a metal electrode 15 made of stainless steel, copper, aluminum, gold, nickel, etc. is formed by vapor deposition, glow discharge, etc., and a flexible polymer film 16 is stacked and attached. A sealing margin 10a provided on the inward surface of the outer periphery of the polymer film;
16a is irradiated with ultraviolet rays in advance as in Example 1.

Next, an adhesive 17 is applied to the sealing margins 10a and 16a between the transparent flexible polymer film 10 and the flexible polymer film 16 by screen printing or the like, and the adhesive is sealed airtightly. The flexible polymer film 16 does not necessarily have to be transparent, and any film may be used as long as it has excellent heat resistance and processability. Note that the transparent flexible polymer film 10 and the flexible polymer film 16 may be integrally molded without using an adhesive, or may be sealed by heat sealing or heat welding using ultrasonic waves or the like. Also good. One ends of the transparent conductive film 11 and the metal electrode 15 are extended or separate members are joined, and lead wires 18 and 19 are provided to protrude to the outside.

By manufacturing as described above, as in Example 1,
There are no capillaries, bubbles, gaps, etc. after sealing, and it has strength against bending and deformation, especially in high humidity areas, long periods of sunlight irradiation, and environments with corrosive gases such as salt and sulfur. Water and gas will not enter the battery even when used in
Furthermore, it has become possible to provide a flexible thin solar cell whose sealing portion does not peel or break due to heat or temperature changes, and whose practical durability is further improved. Furthermore, the sealing process has become easier, and it has become possible to mass-produce high-quality, inexpensive solar cells with a low defect rate such as poor sealing.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view showing an embodiment of a flexible thin battery manufactured according to the present invention, FIG. 1(b) is a vertical cross-sectional view taken along line I-II in FIG. ) is a plan view showing another example of a flexible thin battery manufactured according to the present invention, and (b) is a longitudinal sectional view taken along line III-IV in (a). 1... Separator 2... Electrolyte holding member 3... Cathode active material layer 4... Anode active material layer 5... Cathode current collector 6...
Anode current collectors 5a, 6a...Lead terminals 7, 8...Flexible exterior members 7a, 8a...Sealing margin 9...Adhesive 10...Transparent flexible polymer film 11.. Transparent conductive film 12.. P-type amorphous silicon layer 13.. Impurity amorphous silicon layer 14.. N-type amorphous silicon layer 15.. Metal electrode 16.. Flexible polymer films 10a, 16a.・Sealing margin 17 ・Adhesive 18, 19 ・Lead wire Patent applicant Tomoyuki Aoki

Claims (1)

[Claims] In a flexible thin battery formed by enclosing a battery power generating element with a flexible exterior member, at least the portion of the flexible exterior member that is to be sealed is subjected to ultraviolet irradiation treatment on the inward surface of the sealing portion in advance. 1. A method for producing a flexible thin battery, the method comprising applying the following steps and sealing the battery airtightly by a bonding process using an adhesive or a welding process by heating.