JP2607557B2 - Thin thermoelectric secondary battery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermal battery, and more particularly to a thin thermoelectric secondary battery usable at 50 ° C. to 100 ° C.

[Problems to be Solved by Conventional Techniques and Inventions] A conventional so-called thermal battery utilizes a so-called Seebeck effect, in which almost all the contacts made of different metals are heated to generate electric power.

Thermal batteries utilizing the Seebeck effect have a temperature of 100 ° C.
If it is not possible to use it at room temperature,
It was necessary to incorporate a heating agent into the battery (Japanese Patent Publication No. 61-55)
224).

Further, since the electrolyte used in these conventional thermal batteries is a liquid, it must be sealed, and there is a possibility of liquid leakage.

On the other hand, lithium secondary batteries are widely used mainly as thin batteries used in cameras, calculators, watches, IC cards, etc., but since the electrolyte used in these batteries is also liquid, there is a risk of liquid leakage. Yes, and 0.05mm thick in structure
It was difficult to: Therefore, the battery thickness of conventional liquid crystal displays and calculators, backup power supplies for IC cards, earphone radios, music box cards, temperature sensors, electronic thermometers, IC lighters, LED lighting, pressure-sensitive buzzers, etc. Therefore, it could not be molded to 0.05 mm or less.

The present invention solves the above-mentioned conventional problems, and without incorporating a heating agent in a battery, for example, a superheated part in a factory, a dashboard of a car on a sunny day, a roof of a sunny day, or a place under direct sunlight in summer. It is an object of the present invention to provide a thermal battery that can generate electricity by utilizing heat of a portion heated to 50 ° C. to 100 ° C., such as an exposed portion of the battery.

Another object of the present invention is to provide a highly safe thin secondary battery having no liquid leakage by using a solid electrolyte as an electrolyte. A further object of the present invention is to provide a thin secondary battery having a thickness of 0.05 mm or less and which is excellent in flexibility.

[Means for Solving the Problems] The thin thermoelectric secondary battery of the present invention that solves such problems includes a positive electrode current collecting layer, a positive electrode active material layer, and a polymer solid electrolyte on an insulator. Layer and a metal thin film layer sequentially laminated,
The polymer solid electrolyte layer is composed of a metal phthalocyanine dispersed in a polymer compound or a metal phthalocyanine dispersed in a polymer compound and doped with iodine, and can be used at 50 ° C to 100 ° C. It is.

Here, the insulator is a flexible glass, wood, plastic, ceramics, paper, or the like, and a plastic film or sheet having strength as a support is particularly desirable. As plastics, polyethylene terephthalate, polycarbonate, polyimide, polyether ketone, polyether ether ketone, polyether sulfone, polyphenylene sulfide, polypropylene,
Examples include polystyrene, polyvinyl chloride, and cellulosic resins.

As a substance forming the current collecting layer of the positive electrode, mainly carbon or a metal oxide is used. In this case, carbon in which carbon particles, carbon fibers or graphite are dispersed in a polymer compound is used. Metal oxides include ITOT (indium tin oxide), indium oxide,
Examples thereof include tin oxide, silver oxide, mercury oxide, copper oxide, and lead dioxide. These may be used alone or dispersed in a polymer compound.

Polymer compounds for dispersing carbon or metal oxides include urethane resins, butyral resins, acrylic resins, vinyl chloride / acid copolymers, polycarbonate resins, ABS
Resin, Teflon resin, natural rubber, polyester resin, alkyd resin, polyamide resin, polyimide resin, epoxy resin, phenol resin, melamine resin, styrene resin, acetal resin, nylon resin, polyolefin resin, cellulose resin, polyvinyl alcohol, polypropylene, poly Acrylamide and the like.

Further, the surface resistance of the current collecting layer is preferably 10 ³ Ωcm ^-1 or less, more preferably 5 × 10 ² Ωcm ^-1 or less by a four-terminal method, in order to enhance the current collecting effect.

The active material layer of the positive electrode is composed of a polymer compound in which manganese dioxide is dispersed.

This polymer compound is made of urethane resin, butyral resin, acrylic resin, vinyl chloride / vinyl acetate copolymer, polycarbonate resin, ABS resin, Teflon resin, natural rubber, polyester resin, alkyd resin, polyamide resin, epoxy resin as well as the current collector layer. Resins, phenol resins, melamine resins, styrene resins, acetal resins, nylon resins, polyolefin resins, cellulose resins, polyvinyl alcohol, polypropylene, polyacrylamide, and the like are used. Since manganese dioxide is the active material of the positive electrode, it is preferably 50 parts by weight or more and 80 parts by weight or less based on the total amount of the active material layer of the positive electrode in view of the battery capacity and practical physical properties.

The polymer solid electrolyte layer is composed of a metal phthalocyanine dispersed in a polymer compound, or a metal phthalocyanine dispersed in a polymer compound and doped with iodine.

This polymer compound is desirably a water-soluble polymer compound in which positive and negative ions can easily move in the battery. As such a water-soluble polymer compound, an aqueous polyurethane, an acrylic copolymer, an aqueous polyurethane-acryl copolymer, a polyvinyl alcohol, Examples include polyvinylpyrrolidone, polyvinyl isobutyl ether, gelatin, carboxymethylcellulose, methylcellulose, gum arabic, alginic acid, constarch, casein, polyphosphoric acid, and the like.

Metal phthalocyanine is iron-phthalocyanine, copper-
Of phthalocyanine, cobalt-phthalocyanine, lead-phthalocyanine, zinc-phthalocyanine, etc., preferably, cobalt-phthalocyanine and copper-phthalocyanine are used.

These metal phthalocyanines are preferably dispersed in an amount of 30 to 80 parts by weight, more preferably 60 to 80 parts by weight, based on the total amount of the solid polymer electrolyte layer.

The polymer solid electrolyte layer may be formed by dispersing metal phthalocyanine in the above polymer compound and forming a film.Furthermore, after this film formation, by doping iodine, a battery having a low thermoelectric temperature can be obtained. it can.

It has been known that the conductivity at room temperature is increased by a factor of 10 ⁷ to 10 ¹¹ when iodine is doped into a film in which metal phthalocyanine is vacuum-deposited (Shirai, Eiji Surface, Vol. 25, No. 7, P427 (1987)). As a result of diligent research on the phenomenon, it has been found that by dispersing metal phthalocyanine in a polymer compound and doping with iodine after film formation, the thermoelectric temperature is lower than simply dispersing the metal phthalocyanine in the polymer compound. Obtained the knowledge that can be.

By using the iodine-doped layer as a polymer solid electrolyte layer after dispersing metal phthalocyanine in a polymer compound and forming a film, the thermoelectric temperature is higher than when using a polymer solid electrolyte layer without iodine doping. About 20
° C.

The metal thin film layer is a layer serving as a negative electrode. As the metal, aluminum, lithium, zinc, platinum, or the like is used, but lithium, aluminum, and zinc are preferable. These metals are formed by a vacuum deposition method, a sputtering method, an ion plating method, an electroless plating method, or the like. In order to prevent electrolytic corrosion, the thickness of the metal thin film layer is desirably 1000 mm or more.

Since lithium and aluminum are easily oxidized, an overcoat may be provided on the metal thin film layer to prevent oxidation.

Each of the current-collecting layer, the active material layer, and the polymer solid electrolyte layer of the positive electrode is formed on a surface of an insulator by mixing a layer-forming substance with a suitable solvent such as water, alcohol, or another organic solvent, and a dispersant. Is formed by sequentially applying and drying.

When a metal oxide is used alone as the current collecting layer, it can be formed by a vacuum evaporation method, a sputtering method, an ion plating method, an electroless plating method, or the like, similarly to the metal thin film layer.

The current collecting layer, active material layer and polymer solid electrolyte layer of these positive electrodes can have a dry film thickness of 20 μm or less, and can be about 1 μm if necessary, and the uppermost metal thin film layer can be obtained by appropriately selecting an insulator. In addition, the battery thickness can be reduced to at least 0.01 mm.

Further, the thin battery of the present invention having such a five-layer structure is a thermal battery usable at 50 ° C to 100 ° C. This is presumably because the DC conductivity increases due to thermal activation of the π-electron system of the polymer solid electrolyte layer 4 as the temperature increases.

Further, the battery can be used as a secondary battery that can be used again after being discharged once and then charged with a constant current. Further, if the thin battery of the present invention is laminated on a tape-like film as an insulator and formed into a tape-like shape, the required amount can be cut and used as needed.

Example 1 Example 1 As shown in FIG. 1, a polyester film (thickness: 50 μm) was used as the insulator 1 and a coating solution having the following formulation was applied using a Mayer bar so that the dry film thickness became 25 μm. Then 100
The resultant was dried at a temperature of 60 ° C. for 5 minutes, and further dried at a temperature of 60 ° C. for 24 hours.

Conductive carbon black (Vulcan XC-72R Cabot) 5 parts by weight Acrylic polyol resin (Acrylic Dick 49-394-I)
M Dai Nippon Ink Co., Ltd.) 30 parts by weight Two-part urethane resin curing agent (Bernock DN-981 Dai Nippon Ink Co., Ltd.) 1.8 parts by weight Methyl ethyl ketone 43.7 parts by weight Toluene 6.5 parts by weight Cyclohexanone 13 parts by weight A ball mill with the above composition For 24 hours to obtain a coating solution.

The surface resistance of the current collecting layer 2 of the positive electrode was 9 × 10 ² Ωcm ⁻¹ by the four-terminal method when the surface resistance was 15 cm × 15 cm.

On the current-collecting layer 2 of the positive electrode, a coating solution having the following formulation was applied using a Mayer bar so as to have a dry film thickness of 15 μm, and dried at 100 ° C. for 5 minutes to obtain an active material layer 3 of the positive electrode.

Manganese dioxide 24 parts by weight Dispersant (Roma PW Sannopco) 1 part by weight Isopropyl alcohol 5 parts by weight Water 60 parts by weight Water-based polyurethane resin (Permarin UA500 Sanyo Chemical Industries, Ltd.) 10 parts by weight The composition of the above composition is 24 by a ball mill. The mixture was dispersed and mixed for a time to obtain a coating solution.

On the active material layer 3 of the positive electrode, a coating solution having the following formulation was applied using a Mayer bar so that the dry film thickness became 10 μm,
For 3 minutes to obtain a polymer solid electrolyte layer 4.

Copper phthalocyanine pigment (Cyanine Blue PRX-S Toyo Ink Industries, Ltd.) 12 parts by weight Dispersant (Roma PW Sannopco) 1 part by weight Isopropyl alcohol 6 parts by weight Water 74 parts by weight Waterborne polyurethane resin (Permarin UA500 Sanyo Chemical Industries, Ltd.) 7 parts by weight The composition having the above composition was dispersed and mixed by a ball mill for 24 hours to obtain a coating solution.

Aluminum was vapor-deposited at 1000 A on the polymer solid electrolyte layer 4 by a vacuum vapor deposition method to form a metal thin film layer 5 serving as a negative electrode.

Thus, a thin thermoelectric secondary battery having a thickness of 0.1001 mm was obtained by sequentially laminating on the insulator 1.

In FIG. 1, discharge characteristics at each temperature were measured by connecting a load resistance of 10 kΩ with A as a positive electrode and B as a negative electrode. The result is shown in FIG.

As shown in FIG. 2, almost no electromotive force was generated at room temperature (25 ° C.), but the performance was sufficient at 50 ° C. to 100 ° C.

The performance of the thin thermoelectric secondary battery at 70 ° C. is shown below.

Size 17cm × 13cm Maximum output 0.64 × 10 ³ W Capacity 1.33 × 10 ⁴ Ah Energy density 5.9 × 10 ² Wh / kg (Calculated based on the time when the electromotive force drops to 0.5V) When the rechargeable battery was used as a power source for the earphone radio at 70 ° C., it was possible to listen well for about one hour.

The thin thermoelectric secondary battery of Example 1 was discharged at 70 ° C., and then discharged and charged at normal temperature under the following conditions. As a result, the discharge characteristics shown in FIG. 3 were obtained.

Size 17cm × 13cm Discharge 10KΩ Load resistance 1 hour Discharge Charge 10μA constant current charge 2 hours charge From the results of the above conditions, it was found that the battery was sufficiently usable as a secondary battery.

Further, the discharge characteristics were measured while changing the area of the thin thermoelectric secondary battery of Example 1. FIG. 4 shows the discharge characteristics at 100 ° C. of the thin thermoelectric secondary batteries I and II having different areas.
The area of I is 17 cm × 13 cm, the area of II is 17 cm × 26 cm, the area of I is half the area of II, and the thicknesses of I and II are the same.

Calculating the capacity of I (Ah) and the capacity of II (Ah) at 100 ° C. gives the following.

I 1.11 × 10 ⁴ Ah II 2.22 × 10 ⁴ Ah (Calculated based on the time when the electromotive force drops to 0.5 V.) Since the capacity of I is half of the capacity of II, The area and capacity of a secondary battery are proportional for the same thickness.

Example 2 After forming the solid electrolyte layer 4 as the polymer solid electrolyte layer 4 in the same manner as in Example 1, 100 mol% of iodine was doped into the metal phthalocyanine by a vacuum evaporation method. Other structures were the same as in Example 1 to obtain a thin thermoelectric secondary battery having a thickness of 0.1001 mm. The discharge characteristics at 50 ° C. and 70 ° C. of this battery were compared with the discharge characteristics at 70 ° C. of the battery of Example 1, and are shown in FIG.

By doping 100% by mole of iodine with respect to metal phthalocyanine, the temperature required to obtain the same level of discharge characteristics as compared to the case of not doping iodine is reduced by about 100%.
The temperature could be lowered by 20 ° C.

When this thin thermoelectric secondary battery was used in an earphone radio at 50 ° C., it was possible to listen well for about one hour.

Example 3 A thin thermoelectric secondary battery having a thickness of 0.0752 mm was formed in the same structure as in Example 1 except that ITO (indium tin oxide) was used for the positive electrode collector 2.

FIG. 6 shows discharge characteristics of the thin thermoelectric secondary battery at 50 ° C., 70 ° C., and 100 ° C.

 As shown in FIG. 6, sufficient performance was obtained.

Example 4 A 4 μm-thick polyester film was used as the insulator 1, and the polymer solid electrolyte layer 4 was made 5 μm in thickness with the same formulation as in Example 1;
A 91mm thin thermoelectric secondary battery was created.

FIG. 7 shows the discharge characteristics at 50 ° C., 70 ° C., and 100 ° C.

 As shown in FIG. 7, sufficient performance was obtained.

Example 5 A polyester film having a thickness of 1 μm was used for an insulator 1, and a current-collecting layer 2 of a positive electrode was formed to a thickness of 2 μm in the same manner as in Example 1.
The active material layer 3 of the positive electrode had a thickness of 4 μm in the same formulation as in Example 1, the solid polymer electrolyte layer 4 had a thickness of 2.9 μm in the same formulation as in Example 1, and the other structures were the same as those in Example 1. As the thickness
A thin thermoelectric secondary battery of 0.01 mm was made.

The discharge characteristics were as shown in FIG. 8, and sufficient performance was obtained.

[Effects of the Invention] As is clear from the above embodiments, the thin thermoelectric secondary battery of the present invention does not require a heating agent and can be used at 50 to 100 ° C. Electricity can be generated using light or the like.

In addition, since the polymer solid electrolyte is used, there is no danger of liquid leakage and the safety is high. Furthermore, since the thin thermoelectric secondary battery according to the present invention is formed by sequentially laminating an electrode layer and an electrolyte layer on a flexible film or sheet, the manufacturing method is easy and inexpensive. it can.
In addition, since it is excellent in flexibility and can be molded to a thickness of about 0.01 mm, for example, liquid crystal display, calculator, backup power supply for IC card, earphone radio, music box card, temperature sensor, IC writer, LED lighting, pressure sensitivity It can be widely used as a buzzer, etc., and is extremely effective for industrial use.

[Brief description of the drawings]

FIG. 1 is a diagram showing the structure of the present invention, and FIGS. 2 to 8 are diagrams showing discharge characteristics of Examples 1 to 5.

Claims (6)

(57) [Claims] 1. A positive electrode current collecting layer, a positive electrode active material layer, a polymer solid electrolyte layer and a metal thin film layer are sequentially laminated on an insulator, and the polymer solid electrolyte layer is formed of metal phthalocyanine. A thin thermoelectric secondary battery comprising a compound dispersed in a compound or a metal phthalocyanine dispersed in a polymer compound and doped with iodine. 2. The thin thermoelectric secondary battery according to claim 1, wherein the insulator is a flexible film or sheet. 3. The thin thermoelectric secondary battery according to claim 1, wherein the current-collecting layer of the positive electrode is formed by dispersing carbon particles, carbon fibers, or graphite in a polymer compound. battery. 4. The thin thermoelectric secondary battery according to claim 1, wherein the current collecting layer of the positive electrode is made of a metal oxide or a metal oxide dispersed in a polymer compound. Earth. 5. The thin thermoelectric secondary battery according to claim 1, wherein the active material layer of the positive electrode is obtained by dispersing manganese dioxide in a polymer compound. 6. The thin thermoelectric secondary battery according to claim 1, wherein the thickness of the metal thin film layer is 1000 ° or more.