JP2023035258A - silver oxide battery - Google Patents

Abstract

To provide a long life silver oxide battery.SOLUTION: A silver oxide battery contains a positive electrode, a negative electrode, a separator, and an electrolyte in a battery container. The battery container is formed by joining a positive electrode can and a negative electrode can via a resin gasket and a sealant layer provided on the negative electrode can side of the resin gasket, and the sealant layer includes a layer of a rubber-based sealant positioned on the negative electrode can side, and a layer of an asphalt-based sealant positioned on the resin gasket side.SELECTED DRAWING: Figure 1

Description

The present invention relates to silver oxide batteries.

Conventionally, silver oxide batteries have been used as power sources for small electronic devices such as wristwatches.

A silver oxide battery normally contains a positive electrode with silver oxide as an active material, zinc, etc., in a space defined by a positive electrode can, a negative electrode can (negative electrode terminal plate and sealing plate), and a resin gasket. It is a battery in which power generation elements such as a negative electrode, a separator, and an electrolytic solution are accommodated (see Patent Document 1). The opening of the positive electrode can is usually sealed by fitting the positive electrode can and the negative electrode can via a resin gasket and joining them using a joining technique such as caulking.

Here, in a silver oxide battery, a sealant is usually applied to the contact portion between the negative electrode can and the resin gasket in order to improve the sealing performance of the fitting portion. For example, Patent Document 2 discloses a silver oxide battery in which asphalt pitch (sealant) is applied between the peripheral edge of a cathode sealing plate (negative electrode can) and the inner peripheral edge of an insulating packing (resin gasket). . In recent years, it has been proposed to use rubber-based sealing agents such as butadiene rubber and styrene-butadiene rubber instead of such asphalt-based sealing agents (see, for example, Patent Documents 3 and 4).

JP 2006-120549 A JP-A-58-019853 JP-A-11-40118 WO2019/049833

By the way, in recent years, there has been an increasing demand for longer life of silver oxide batteries. However, the conventional silver oxide battery has the problem that the electrolyte may leak from between the negative electrode can and the resin gasket depending on the usage conditions, shortening the life of the battery.
Therefore, the conventional silver oxide battery has room for improvement in terms of suppressing leakage of the electrolyte to extend the life of the battery.

Accordingly, an object of the present invention is to provide a long-life silver oxide battery.

As a result of intensive studies, the inventors of the present invention have found that if different types of predetermined sealing agents are applied to the negative electrode can side and the resin gasket side, respectively, to seal the opening of the positive electrode can, electrolyte leakage can be effectively prevented. The present inventors have found that it is possible to suppress it, thereby realizing a long life of a silver oxide battery, and completed the present invention.

An object of the present invention is to advantageously solve the above-mentioned problems. A silver oxide battery of the present invention comprises a battery container containing a positive electrode, a negative electrode, a separator and an electrolytic solution. The battery container is formed by joining a positive electrode can and a negative electrode can via a resin gasket and a sealing agent layer provided on the negative electrode can side of the resin gasket, and the sealing agent layer is It is characterized by comprising a layer of a rubber-based sealing agent positioned on the negative electrode can side and a layer of an asphalt-based sealing agent positioned on the resin gasket side. Thus, if a sealant layer comprising a layer of rubber-based sealant positioned on the negative electrode can side and a layer of asphalt-based sealant positioned on the resin gasket side is used, the It is possible to satisfactorily suppress the leakage of the electrolyte solution. Therefore, the life of the silver oxide battery can be extended.

Moreover, in the silver oxide battery of the present invention, it is preferable that the rubber-based sealant contains a rubber-based polymer having a glass transition temperature of 0° C. or lower. As described above, if a rubber-based sealant containing a rubber-based polymer having a glass transition temperature of 0° C. or less is used, the adhesion and flexibility of the rubber-based sealant layer to the negative electrode can are improved, and leakage of the electrolyte is prevented. Liquid can be further suppressed, and the life of the silver oxide battery can be further extended.
In the present invention, the glass transition temperature of the rubber polymer can be measured by the method described in Examples.

Moreover, in the silver oxide battery of the present invention, it is preferable that the asphalt-based sealant contains blown asphalt. Thus, the use of an asphalt-based sealant containing blown asphalt improves the adhesion of the asphalt-based sealant layer to the resin gasket, further suppressing leakage of the electrolyte, thereby improving the silver oxide battery. Life can be further extended.

Moreover, in the silver oxide battery of the present invention, it is preferable that the resin gasket is made of nylon 66. By using the sealing agent layer described above, even when the resin gasket is made of nylon 66, leakage of the electrolyte can be suppressed, and the life of the silver oxide battery can be extended.

Moreover, in the silver oxide battery of the present invention, it is preferable that the surface of the negative electrode can that comes into contact with the sealant layer is made of copper. By using the sealant layer described above, even when the surface of the negative electrode can that comes into contact with the sealant layer is made of copper, leakage of the electrolyte can be suppressed, and the life of the silver oxide battery can be extended. be able to.

According to the present invention, it is possible to provide a long-life silver oxide battery.

1 is a cross-sectional view of a silver oxide battery according to one embodiment of the present invention; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.

(silver oxide battery)
The silver oxide battery of the present invention contains a positive electrode, a negative electrode, a separator and an electrolytic solution in a battery container. The battery container is formed by joining the positive electrode can and the negative electrode can via a resin gasket and a sealant layer provided on the negative electrode can side of the resin gasket, and the sealant layer is formed on the negative electrode can side. It has a layer of rubber-based sealant positioned thereon and a layer of asphalt-based sealant positioned on the side of the resin gasket. With such a configuration, in the silver oxide battery of the present invention, leakage of the electrolyte from between the negative electrode can and the resin gasket can be satisfactorily suppressed, and the life of the battery can be extended.
The silver oxide battery of the present invention is not particularly limited in other configurations and structures as long as the opening of the positive electrode can is sealed by the negative electrode can, the resin gasket, and the sealant layer to prevent electrolyte leakage. Configurations and structures employed in conventionally known silver oxide batteries can be applied. For example, the shape of the silver oxide battery of the present invention may be a flat shape (coin shape, button shape, etc.) or a cylindrical shape (cylindrical shape, square tube shape, etc.).

A silver oxide battery according to an embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view of a silver oxide battery according to one embodiment of the invention. A silver oxide battery 10 shown in FIG. 1 is an example of a flat silver oxide battery of the present invention, and includes a positive electrode can 1, a positive electrode 2, a separator 3, a resin gasket 4, and a rubber seal layer. 5a and an asphalt-based sealant layer 5b, a negative electrode 6, a negative electrode can 7, and an electrolytic solution (not shown). A resin gasket 4 is arranged in the opening of the positive electrode can 1 , and the negative electrode can 7 is joined to the positive electrode can 1 via the resin gasket 4 and the sealant layer 5 . As a result, the opening of the positive electrode can 1 is sealed, and the inside of the battery is hermetically sealed. That is, in the silver oxide battery 10 shown in FIG. 1, the positive electrode 2, the separator 3, and the negative electrode are contained in the space (sealed space) of the battery container composed of the positive electrode can 1, the resin gasket 4, the sealant layer 5, and the negative electrode can 7. 6, and the electrolyte is contained. An additional layer of sealant may be provided between the positive electrode can 1 and the resin gasket 4 .

<Positive electrode can>
The positive electrode can 1 is, for example, a member having a shape in which a flange is provided at the opening edge of a bottomed cylindrical body, and which also serves as a positive electrode terminal. As the positive electrode can 1, for example, nickel-plated iron can be used.

<Positive electrode>
The positive electrode 2 is arranged in the positive electrode can 1 so as to be in contact with the inner surface of the cylindrical portion of the positive electrode can 1 . The positive electrode 2 contains silver oxide as a positive electrode active material and an electrolytic solution to be described later, and is obtained by pressure-molding a positive electrode mixture that optionally contains a conductive aid such as graphite, ketjen black, or acetylene black. It can be configured by a positive electrode mixture molded body.

<Separator>
The separator 3 is a member arranged between the positive electrode 2 and the negative electrode 6 in the positive electrode can 1 . The separator 3 is not particularly limited, and non-woven fabric mainly composed of vinylon or rayon, vinylon/rayon non-woven fabric (vinylon/rayon mixed paper), polyamide non-woven fabric, polyolefin/rayon non-woven fabric, vinylon paper, vinylon linter pulp paper, vinylon/linter pulp paper, Mercerized pulp paper and the like can be used. In addition, a hydrophilized microporous polyolefin film (microporous polyethylene film, microporous polypropylene film, etc.), a cellophane film, and a liquid-absorbing layer (electrolyte holding layer) such as a vinylon/rayon mixed paper are stacked. can also be used as a separator.

<Resin gasket>
The resin gasket 4 is a member arranged on the flange portion of the positive electrode can 1 to seal the opening of the positive electrode can 1 together with the sealant layer 5 and the negative electrode can 7 . The resin gasket 4 normally has an annular shape in plan view, and a substantially L-shaped cross section in the thickness direction.
The resin constituting the resin gasket 4 is not limited, and polyolefin resins such as polyethylene and polypropylene; polyamide resins such as nylon 6 and nylon 66; fluorine resins; silicone resins and the like can be used. These resins may be used individually by 1 type, and may be used in combination of 2 or more types.
From the viewpoint of further suppressing leakage of the electrolyte from between the resin gasket 4 and the negative electrode can 7, at least the portion of the resin gasket 4 that contacts the asphalt-based sealant layer 5b is made of nylon 66. More preferably, the resin gasket 4 is entirely made of nylon 66.

<Sealant layer>
The sealant layer 5 is arranged at a portion where the resin gasket 4 and the negative electrode can 7 are in contact with each other. Specifically, the sealant layer 5 is disposed between the surface of the resin gasket 4 on the side opposite to the positive electrode can 1 side and the edge of the negative electrode can 7 . It's in close contact.
In the illustrated example, the sealant layer 5 has a two-layer structure of a rubber-based sealant layer 5a and an asphalt-based sealant layer 5b, and the rubber-based sealant layer 5a and the asphalt-based sealant layer 5b are in close contact with each other. Further, the rubber-based sealant layer 5a is positioned on the negative electrode can 7 side and is in close contact with the negative electrode can 7. As shown in FIG. The asphalt-based sealant layer 5b is located on the resin gasket 4 side and is in close contact with the resin gasket 4. As shown in FIG. With such a configuration, leakage of the electrolyte from between the negative electrode can 7 and the resin gasket 4 can be satisfactorily suppressed, and the service life of the silver oxide battery 10 can be extended. Although the reason why such a configuration can satisfactorily suppress leakage of the electrolyte from between the negative electrode can 7 and the resin gasket 4 is not necessarily clear, it is presumed as follows. That is, a rubber-based sealant that adheres well to a metal can does not adhere well to a resin gasket, and an asphalt-based sealant that adheres well to a resin gasket does not adhere well to a metal can. is. On the other hand, the present inventors found that the adhesion between the rubber sealant and the asphalt sealant is good. For this reason, it is presumed that the above-described configuration can provide a higher leakage prevention performance than the leakage prevention performance of each of the rubber-based sealing agent and the asphalt-based sealing agent alone.

The thickness of the sealant layer 5 may be arbitrarily selected according to the size of the silver oxide battery 10 and the like, and is usually 1 μm or more and 100 μm or less. When the thickness of the sealant layer 5 is equal to or less than the upper limit of the above range, the sealant layer 5 can be easily formed. In addition, since the thickness of the sealant layer is equal to or greater than the lower limit of the above range, the opening of the positive electrode can 1 is well sealed. Therefore, leakage of the electrolytic solution can be further suppressed, and the life of the silver oxide battery can be further extended.

<<Rubber-based sealant layer>>
The rubber sealant layer 5a is a layer made of a rubber sealant. The rubber-based sealant layer 5a constitutes the sealant layer 5 together with the asphalt-based sealant layer 5b. The rubber-based sealant layer 5 a is provided in a portion that contacts the negative electrode can 7 . Specifically, the rubber-based sealant layer 5a is provided on the negative electrode can 7 side of the portion where the negative electrode can 7 and the resin gasket 4 abut.
The thickness of the rubber-based sealant layer 5a is not limited as long as the leakage of the electrolyte can be suppressed. It is more preferably 10 μm or less, and more preferably 5 μm or less.

A rubber-based sealant contains a rubber-based polymer as a main component, and may optionally contain inorganic fillers and/or additives.
In the present invention, "comprising a rubber-based polymer as a main component" means that the content of the rubber-based polymer is 50% by mass or more based on 100% by mass of the rubber-based sealant. The content of the rubber-based polymer in the rubber-based sealant is preferably 60% by mass or more, more preferably 65% by mass or more. Also, the content of the rubber-based polymer is preferably 95% by mass or less, more preferably 80% by mass or less.
In addition, the rubber-based sealant may be made of a rubber-based polymer.

[Rubber-based polymer]
Rubber-based polymers include, but are not limited to, diene-based non-block polymers, isobutene-based polymers, and ethylene-propylene-based copolymers.
The rubber-based polymer includes, for example, at least one selected from diene-based non-block polymers, isobutene-based polymers and ethylene-propylene-based polymers. In the present invention, the ratio of each polymer can be measured using liquid chromatography/mass spectrometry.
The rubber-based polymer is preferably composed of at least one selected from the group consisting of a diene-based non-block polymer, an isobutene-based polymer, and an ethylene-propylene-based polymer. - It is more preferably made of a propylene-based polymer.

-Diene non-block polymer-
Examples of diene-based non-block polymers include homopolymers of one type of diene-based monomer, random copolymers of two or more types of diene-based monomers, and diene-based monomers and the diene-based Random copolymers of comonomers copolymerizable with monomers are included. These polymers can be used individually by 1 type or in combination of 2 or more types.
Among these, the diene-based non-block polymer is preferably a homopolymer of one type of diene-based monomer, more preferably polybutadiene. The use of polybutadiene makes it possible to obtain a rubber-based sealant that is excellent in flexibility, further suppresses electrolyte leakage, and is capable of extending the service life of silver oxide batteries. Here, the diene-based non-block polymer preferably does not contain polar groups such as acidic groups.

The diene-based monomer capable of forming the diene-based non-block polymer is not particularly limited. -pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4,5-dimethyl-1,3-octadiene and other conjugated diene monomers. Among them, 1,3-butadiene is preferable as the diene-based monomer.
In addition, these diene monomers can be used individually by 1 type or in combination of 2 or more types.

In addition, the comonomer is not particularly limited, and examples thereof include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, t-butylstyrene, divinylbenzene, N, aromatic vinyl monomers such as N-dimethyl-p-aminoethylstyrene, N,N-diethyl-p-aminoethylstyrene, 2,4-dimethylstyrene, butoxystyrene, vinylnaphthalene and vinylanthracene; Among them, the comonomer is preferably a monomer having no polar group such as an acidic group, and more preferably styrene.
In addition, these comonomers can be used individually by 1 type or in combination of 2 or more types.
When the rubber-based polymer consists of a plurality of types, the content of the diene-based non-block polymer is preferably 50% by mass or more, and preferably 60% by mass or more, with the total content of the rubber-based polymer being 100% by mass. is more preferably 99% by mass or less, and more preferably 90% by mass or less.

-Isobutene polymer-
Isobutene-based polymers include, for example, isobutene homopolymers (polyisobutene), and random copolymers of isobutene and comonomers copolymerizable with the isobutene. These polymers can be used individually by 1 type or in combination of 2 or more types.
When the rubber-based polymer is composed of a plurality of types, the content of the isobutene-based polymer is preferably 50% by mass or more, and is 60% by mass or more, based on the total content of the rubber-based polymer being 100% by mass. is more preferably 99% by mass or less, and more preferably 90% by mass or less.

-Ethylene-Propylene Copolymer-
The ethylene-propylene copolymer is not particularly limited as long as it is a copolymer obtained by copolymerizing at least an ethylene monomer and a propylene monomer. Examples include an ethylene-propylene copolymer (EPM) and ethylene A propylene diene copolymer (EPDM) may be mentioned. Here, the ethylene-propylene copolymer preferably does not contain a polar group such as an acidic group.
When the rubber polymer is composed of multiple types, the content of the ethylene-propylene copolymer is preferably 50% by mass or more, preferably 60% by mass, with the total content of the rubber polymer being 100% by mass. It is more preferably 99% by mass or less, and more preferably 90% by mass or less.

-Glass-transition temperature-
From the viewpoint of improving the adhesion and flexibility of the rubber-based sealant layer 5a to the negative electrode can 7 and further suppressing leakage of the electrolytic solution to further extend the life of the silver oxide battery, the rubber-based polymer described above is used. The glass transition temperature is preferably 0° C. or lower, more preferably -10° C. or lower, and preferably -80° C. or higher in order to prevent the parts from adhering to each other after applying the sealant. It is more preferably 60°C or higher.
The glass transition temperature of the rubber-based polymer is changed, for example, by changing the type and/or amount of the monomer used in the polymerization reaction, and changing the type and/or abundance of the monomer unit in the rubber-based polymer. can be adjusted as appropriate.

‐Mooney Viscosity‐
From the viewpoint of further suppressing electrolyte leakage and extending the life of the silver oxide battery, the Mooney viscosity (ML1+4, 100° C.) of the rubber-based polymer is preferably 35 or more, and 40 or more. more preferably 80 or less, more preferably 75 or less.
The Mooney viscosity of the rubber-based polymer can be appropriately adjusted, for example, by adjusting the polymerization conditions.
The Mooney viscosity (ML1+4, 100° C.) of the rubber polymer can be determined by the method described in Examples.

-polymerization-
The rubber-based polymer can be obtained by polymerizing monomers by a conventionally known method in the presence of a polymerization initiator. The form of the polymerization reaction may be solution polymerization, slurry polymerization, or the like, but reaction heat can be easily removed when solution polymerization is used.

[Inorganic filler]
The rubber sealant may contain an inorganic filler for coloring. The inorganic filler that can optionally be included is not particularly limited, and for example, carbon black, graphite, and the like can be used in the case of blackening. Specific examples of carbon black include furnace black, channel black, and the like. Specific examples of graphite include scale-like natural graphite and artificial graphite.
These inorganic fillers can be used individually by 1 type or in combination of 2 or more types.

When the rubber-based sealing agent is applied to the edge of the negative electrode can 7, the rubber-based sealing agent is added in an amount of 100 parts by mass based on the solid content of all the polymer components described above, from the viewpoint of making it easier to visually recognize coating unevenness of the sealing agent layer. It is preferable that 0.1 parts by mass or more and 10 parts by mass or less of inorganic filler is included.

[Additive]
Additives that the rubber-based sealant of the present invention may optionally contain are not particularly limited. agents.

Polymeric additives include aromatic vinyl-conjugated diene block polymers.
Examples of aromatic vinyl-conjugated diene block polymers include styrene-isoprene block copolymers and styrene-butadiene block copolymers. As the aromatic vinyl-conjugated diene block polymer, any of diblock copolymers, triblock copolymers and mixtures thereof can be preferably used. Triblock copolymers include styrene-isoprene-styrene block copolymers (SIS) and styrene-butadiene-styrene block copolymers (SBS).

The content of the aromatic vinyl-conjugated diene block polymer, which is a polymer additive, is preferably 50% by mass or less, more preferably 45% by mass or less, based on 100% by mass of the rubber sealant.

Here, the aromatic vinyl-conjugated diene block polymer may be hydrogenated. That is, the rubber-based sealant may contain a hydrogenated aromatic vinyl-conjugated diene block polymer as a rubber-based polymer. The hydrogenated aromatic vinyl-conjugated diene block polymer can be obtained by the hydrogenation reaction of the aromatic vinyl-conjugated diene block polymer described above. Hydrogenation can be carried out by a conventionally known method using a hydrogenation catalyst.
The hydrogenation rate of the carbon-carbon unsaturated bonds in the main chain and side chains of the hydrogenated product of the aromatic vinyl-conjugated diene block polymer is preferably 90% or more as measured by ¹ H-NMR. % or more, preferably 95% or more. The hydrogenation rate can be adjusted by changing the type of hydrogenation catalyst, the temperature of the hydrogenation reaction and/or the hydrogen pressure.
The degree of hydrogenation was measured by measuring ¹ H-NMR spectra before and after the hydrogenation reaction, and the amount of decrease in the integrated value of the signal corresponding to the carbon-carbon unsaturated bond of the main chain and side chain portions before and after the hydrogenation reaction. can be calculated by obtaining

A specific example of the hydrogenated aromatic vinyl-conjugated diene block polymer is a hydrogenated styrene-isoprene-styrene block copolymer (SIS), that is, a styrene-ethylene-propylene-styrene block copolymer ( SEPS); a hydrogenated product of styrene-butadiene-styrene block copolymer (SBS), ie, styrene-ethylene-butylene-styrene block copolymer (SEBS). Among these, styrene-ethylene-butylene-styrene block copolymer (SEBS) is preferred.
Hydrogenated aromatic vinyl-conjugated diene block polymers are commercially available, and specific examples thereof include Tuftec (registered trademark) H1052 manufactured by Asahi Kasei Chemicals Corporation.

The content of the hydrogenated product of the aromatic vinyl-conjugated diene block polymer is preferably 50% by mass or less, more preferably 45% by mass or less, based on 100% by mass of the rubber sealant.

Examples of stabilizers include phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and the like. Among these, phenolic antioxidants are preferred, and alkyl-substituted phenolic antioxidants are more preferred.
These stabilizers can be used singly or in combination of two or more.

Examples of ultraviolet absorbers include benzotriazole-based ultraviolet absorbers, benzoate-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, acrylate-based ultraviolet absorbers, metal complex-based ultraviolet absorbers, and organic substances such as salicylic acid esters, or fine particles. Inorganic substances such as zinc oxide, cerium oxide, and titanium oxide can be used.

The amount of the stabilizer and the ultraviolet absorber to be blended is not particularly limited, and may be appropriately selected according to the purpose of use. is preferred.

<<Asphalt-based sealant layer>>
The asphalt-based sealant layer 5b is a layer made of an asphalt-based sealant. The asphalt-based sealant layer 5b constitutes the sealant layer 5 together with the rubber-based sealant layer 5a. The asphalt-based sealant layer 5b is provided at least at a portion where the negative electrode can 7 and the resin gasket 4 abut. Specifically, the asphalt-based sealant layer 5b is provided at least on the resin gasket 4 side of the portion where the resin gasket 4 and the negative electrode can 7 abut. The asphalt-based sealant layer 5 b may be provided so as to cover the entire surface of the resin gasket 4 .
The thickness of the asphalt-based sealant layer 5b at the portion that abuts on the resin gasket 4 is not limited as long as the leakage of the electrolyte can be suppressed. It is preferably 1 μm or more, more preferably 10 μm or less, and more preferably 5 μm or less.

The asphalt contained in the asphalt-based sealing agent is not particularly limited, but blown asphalt is preferable from the viewpoint of improving adhesion to resin gaskets and handling during production. Asphalt other than blown asphalt that can be contained in the asphalt-based sealing agent is not particularly limited, and conventionally known asphalts used in sealing agents can be used.
As for the properties of the asphalt, the softening point is preferably 50° C. or higher, more preferably 60° C. or higher. Also, the softening point of asphalt is preferably 100° C. or lower, more preferably 90° C. or lower.
The asphalt penetration is preferably 60 or less, more preferably 40 or less.
In the present invention, the softening point and penetration of asphalt can be measured by the methods described in Examples.
The asphalt-based sealant may be made of asphalt, and may contain several mass % of a synthetic resin as an additive. The synthetic resin that can be contained in the asphalt-based sealing agent is not particularly limited, and conventionally known synthetic resins used in asphalt-based sealing agents can be used.

<Negative Electrode>
A negative electrode 6 is placed in a negative electrode can 7 . The negative electrode 6 usually contains zinc or a zinc alloy as a negative electrode active material and an electrolytic solution described later, and optionally may further contain a gelling agent and the like. Zinc alloys contain, for example, indium or bismuth. However, from the viewpoint of suppressing environmental pollution, it is preferable that the zinc alloy does not contain mercury as an alloy component.
Examples of gelling agents that can be used include sodium polyacrylate and carboxymethylcellulose.

<Negative electrode can>
The negative electrode can 7 is a member that is fitted with the resin gasket 4 so that the edge thereof is in contact with the resin gasket 4 via the sealant 5, and also serves as a negative electrode terminal. As described above, the rubber-based sealant layer 5 a is provided on the portion of the negative electrode can 7 that contacts the resin gasket 4 .
Here, at least the surface (portion) of the negative electrode can 7 that contacts the sealant layer 5, preferably the entire inner surface, is preferably made of copper or a copper alloy, and more preferably made of copper. If at least the surface of the negative electrode can 7 in contact with the sealant layer 5 or the entire inner surface of the negative electrode can 7 is made of copper or a copper alloy, for example, when zinc or a zinc alloy is used as the active material of the negative electrode, the active material can be The generation of hydrogen gas due to corrosion (oxidation) of the steel is suppressed. Therefore, leakage of the electrolytic solution can be further suppressed, and the life of the silver oxide battery can be further extended. A copper alloy is, for example, brass.
The negative electrode can 7 has an inner portion in contact with the negative electrode 6 made of copper or a copper alloy, a main body (central) portion made of stainless steel, and an outer portion (that is, the side opposite to the inner side in contact with the negative electrode 6). A clad member having a three-layer structure in which the portion) is made of nickel can be preferably used.

<Electrolyte>
As the electrolytic solution, for example, an alkaline aqueous solution obtained by dissolving an alkali metal hydroxide such as potassium hydroxide, sodium hydroxide, or lithium hydroxide in water can be used. Moreover, the electrolytic solution may contain various known additives within a range that does not impair the effects of the present invention. For example, when zinc or a zinc alloy is used as the active material of the negative electrode 6, the electrolyte may contain zinc oxide in order to prevent corrosion (oxidation) of the active material.

(Manufacturing method of silver oxide battery)
A silver oxide battery 10 has a positive electrode can 2 containing a positive electrode 2, a separator 3, and an electrolytic solution, and a negative electrode can 7 containing a negative electrode 6, with a sealant layer 5 and a resin gasket 4 interposed therebetween. , the edge (flange) of the positive electrode can 1 and the edge of the negative electrode can 7 can be joined by a known processing method such as caulking.

Here, the placement of the sealant layer 5 between the positive electrode can 1 and the negative electrode can 7 is
(1) A method of disposing the sealant layer 5 on the resin gasket 4 placed on the positive electrode can 1 and fitting and bonding it to the negative electrode can 7;
(2) A method in which the sealant layer 5 is placed on the negative electrode can 7 and is fitted and joined to the resin gasket 4 and the positive electrode can 1; or (3) a resin gasket disposed on the positive electrode can 1 A method of disposing an asphalt-based sealant layer 5b on 4, disposing a rubber-based sealant layer 5a on the negative electrode can 7, and fitting and joining them;
It can be done by Among them, the method (3) is preferable from the viewpoint of production efficiency.

The placement of the sealant layer 5 can be performed by coating and drying a sealant solution. Specifically, a sealant solution containing a rubber-based sealant (rubber-based sealant solution) and a sealant solution containing an asphalt-based sealant (asphalt-based sealant solution) are applied and dried to obtain a rubber-based sealant. A sealant layer 5a and an asphalt-based sealant layer 5b can be arranged respectively.

Here, the sealant solution can be prepared, for example, by dissolving a sealant (rubber-based sealant or asphalt-based sealant) in a solvent.
The solvent used for the sealant solution is not limited to a specific solvent, and is capable of dissolving the polymer component and asphalt component in the sealant at room temperature or under heat. Specific examples of solvents include aromatic hydrocarbon compounds such as benzene, toluene, and xylene; Organic solvents such as hydrocarbon compounds; hydrocarbon mixtures such as gasoline and industrial gasoline; Among them, xylene and toluene are preferred, and xylene is more preferred.
The thickness and uniformity of each sealing agent layer can be appropriately controlled by adjusting the sealing agent solution to have an arbitrary solid content concentration. For example, when the solvent is toluene, the asphalt solid content concentration in the asphalt-based sealing agent is preferably 0.5% by mass or more, more preferably 1.0% by mass or more. Further, the solid content concentration of the asphalt is preferably 40% by mass or less, more preferably 30% by mass or less. Moreover, the solid content concentration in the rubber-based sealing agent when toluene is used as the solvent is preferably 5% by mass or more, and more preferably 10% by mass or more. Moreover, the solid content concentration is preferably 40% by mass or less, more preferably 30% by mass or less.

Application of the sealant solution can be performed by supplying it using a metering pump such as an air-driven metering dispenser, a roller pump, or a gear pump. If the amount is small, it may be applied manually using a brush.

The rubber sealant solution is applied, for example, to a portion of the negative electrode can 7 that contacts the resin gasket 4 .
The asphalt-based sealant solution is applied, for example, to at least the portion of the resin gasket 4 that contacts the negative electrode can 7 . When the asphalt-based sealant solution is applied to the entire surface of the resin gasket 4, the application may be performed by immersing the resin gasket 4 in the asphalt-based sealant solution and then pulling it out of the asphalt-based sealant solution. Alternatively, the coating may be performed by enclosing the resin gasket 4 and a predetermined amount of asphalt-based sealing agent solution in a cylindrical container, placing the container on a ball mill stand for a certain period of time, and rotating the container.

The method for drying the applied sealant solution is not limited, but for example, it can be dried naturally or forcedly dried using a heating device. Forced drying using a heating device enables drying in a short period of time, making the drying process more industrially suitable.

When using a heating device, the solvent is usually removed by drying at about 50° C. for about 10 minutes. The residual concentration of the solvent in the sealant layer 5 is preferably 5% by mass or less, more preferably 1% by mass or less, and more preferably 0.1% by mass or less by removing the solvent by drying. More preferably, it is particularly preferably 0.05% by mass or less. If the drying temperature of the solvent is higher than or near the boiling point of the solvent, foaming may occur and the surface may become uneven. Therefore, the drying temperature is preferably determined according to the properties of the solvent. The drying temperature is preferably 10° C. or more, more preferably 30° C. or more lower than the boiling point of the solvent.

EXAMPLES The present invention will be described below with reference to Examples, but the present invention is not limited to these. Parts and percentages in the examples are based on mass unless otherwise specified. Various measurements and evaluations in Examples and Comparative Examples were carried out according to the following methods.

(Measurement of glass transition temperature)
The glass transition temperature of the rubber polymer was measured using a differential thermal balance (TG-DTA).

(Measurement of Mooney viscosity)
The Mooney viscosity (ML1+4 100° C.) of the rubber polymer was measured using a Mooney viscometer according to JIS K 6300-1.

(Evaluation of leakage resistance)
Each silver oxide battery produced in Examples and Comparative Examples was placed in a thermo-hygrostat at a temperature of 80° C. and a humidity of 80%. The temperature was returned to room temperature every 5 days, and the silver oxide battery was put into ion-exchanged water. Then, phenolphthalein was added dropwise to the deionized water as an indicator. When discoloration of the ion-exchanged water was visually observed, it was determined that the electrolyte had leaked from the silver oxide battery.
The longer the number of days until discoloration of the ion-exchanged water is observed, the better the leakage resistance. If no discoloration was observed even after 30 days, it was judged as "no leakage".

(Production example 1)
<Production of rubber-based sealant 1>
<<Synthesis of polybutadiene>>
5,000 g of toluene and 810 g of butadiene were added to a 10-liter autoclave equipped with a stirrer, and after sufficient stirring, 0.27 mol of diethylaluminum chloride and 0.6 mmol of chromium chloride-pyridine complex were added and polymerized at 60° C. for 3 hours with stirring. After that, 100 ml of methanol was added to terminate the polymerization. After stopping the polymerization, the polymer solution was taken out after cooling to room temperature. After steam coagulation of the resulting polymer solution, it was vacuum-dried at 60° C. for 48 hours to obtain 780 g of solid polybutadiene.

The glass transition temperature and Mooney viscosity of the synthesized polybutadiene were measured. Table 1 shows the results.

Tuftec (registered trademark) H1052 manufactured by Asahi Kasei Chemicals Corporation was prepared as a styrene-ethylene-butylene-styrene block copolymer (hereinafter simply referred to as "SEBS") as a polymer additive.

Then, the synthesized polybutadiene and SEBS were mixed so that 75% by mass of polybutadiene and 25% by mass of SEBS were mixed with 100% by mass of the rubber-based sealing agent to produce a rubber-based sealing agent 1 .

<Preparation of rubber sealant solution 1>
The rubber-based sealing agent 1 obtained as described above was added to xylene so that the solid content concentration was 8% by mass to prepare a rubber-based sealing agent solution 1 .

(Production example 2)
<Production of rubber-based sealant 2>
<<Ethylene-propylene copolymer>>
As an ethylene-propylene copolymer, an ethylene propylene diene copolymer (hereinafter simply referred to as "EPDM") (EPT3080M manufactured by Mitsui Chemicals) was prepared.
The EPDM glass transition temperature and Mooney viscosity were measured. Table 1 shows the results.

Then, EPDM and SEBS ("Tuftec (registered trademark) H1052" manufactured by Asahi Kasei Chemicals Co., Ltd.) are mixed so that EPDM is 60% by mass and SEBS is 40% by mass, based on 100% by mass of rubber sealant, A rubber sealant 2 was produced.

<Preparation of rubber sealant solution 2>
The rubber-based sealing agent 2 obtained as described above was added to xylene so that the solid content concentration was 10% by mass to prepare a rubber-based sealing agent solution 2 .

(Production example 3)
<Preparation of asphalt sealant>
Commercially available blown asphalt containing 3% by mass of synthetic resin was used as the asphalt sealant. The softening point and penetration (25°C) of the blown asphalt were measured according to JIS K-2207 and confirmed to be 85°C and 35, respectively.

<Preparation of asphalt sealant solution>
Then, the above asphalt-based sealing agent was added to xylene so that the solid content concentration was 8% by mass to prepare an asphalt-based sealing agent solution.

(Example 1)
<Production of silver oxide battery>
95 parts by mass of granulated silver(I) oxide having an average particle diameter of 150 μm and a bulk density of 2.4 g/cm ³ , which is a positive electrode active material, and 5 parts by mass of graphite, which is a conductive additive, are mixed to obtain a mixture. This mixture is filled in a mold and pressure-molded into a disk having a diameter of 10.9 mm and a height of 1.9 mm at a packing density of 5.5 g/cm ³ to obtain a positive electrode mixture molded body. A part of the alkaline electrolyte described below was impregnated in this.
For the negative electrode, 0.2 g of mercury-free zinc particles with an average particle size of 120 μm were used. A 36% by mass potassium hydroxide aqueous solution in which 4% by mass of zinc oxide was dissolved was used as the alkaline electrolyte. Moreover, the positive electrode can was produced using SUS430.
For the separator, "YG2152" from Yuasa Membrane System Co., Ltd., which is a laminate of a cellophane film with a thickness of 20 μm and a graft film with a thickness of 30 μm, and a vinylon-rayon mixed paper with a thickness of 400 μm as an electrolyte retention layer. A separator was formed by punching out a circle having a diameter of 11.3 mm and stacking them.
The graft film is composed of a graft copolymer having a structure in which acrylic acid is graft-copolymerized to a polyethylene main chain.
As the gasket, an annular gasket made of nylon 66 having an asphalt-based sealing agent layer formed on the surface thereof with a thickness of 2 μm was used. Formation of the asphalt-based sealant layer was performed by the following procedure. An annular gasket made of nylon 66 and the asphalt-based sealant solution were enclosed in a cylindrical plastic container, and rotated at a rotation speed of 40 rpm for 30 minutes on a ball mill stand. An asphalt-based sealant layer was formed on the
The amount of the asphalt-based sealant solution was 15 mL per 100 g of gasket.
A copper-stainless steel (SUS304)-nickel clad plate was used for the negative electrode can. The rubber-based sealant solution 1 prepared in Production Example 1 was applied with a brush to the edge of the negative electrode can where the gasket abuts, and dried to form a rubber-based sealant with a thickness of 3 μm. A sealant layer was formed.
A flat plate with a diameter of 11.5 mm and a thickness of 5.4 mm having the structure shown in FIG. A type silver oxide battery was fabricated.
Then, the silver oxide battery assembled as described above was subjected to a leakage resistance test. Table 2 shows the results.

(Example 2)
In Example 1, instead of the rubber-based sealant solution 1 prepared in Production Example 1, the rubber-based sealant solution 2 prepared in Production Example 2 was used to form a rubber-based sealant layer on the negative electrode can. A silver oxide battery was produced in the same manner as in Example 1, and the leakage resistance was evaluated. Table 2 shows the results.

(Comparative example 1)
A silver oxide battery was produced in the same manner as in Example 1, except that the rubber sealant layer was not formed on the edge of the negative electrode can, and the leakage resistance was evaluated. Table 2 shows the results.

(Comparative example 2)
In Example 1, the asphalt-based sealant solution prepared in Production Example 3 was used in place of the rubber-based sealant solution 1 prepared in Production Example 1, and the asphalt-based sealant solution was applied to the edge of the negative electrode can to a thickness of 2 μm. A silver oxide battery was produced in the same manner as in Example 1 except that the layer was formed, and the leakage resistance was evaluated. Table 2 shows the results.

(Comparative Example 3)
In Example 1, instead of the asphalt-based sealant solution prepared in Production Example 3, the rubber-based sealant solution 1 prepared in Production Example 1 was used to form a rubber-based sealant layer with a thickness of 3 μm on the resin gasket. A silver oxide battery was produced in the same manner as in Example 1 except that the was formed, and the leakage resistance was evaluated. Table 2 shows the results.

(Comparative Example 4)
A silver oxide battery was produced in the same manner as in Comparative Example 3, except that a rubber sealant layer was not provided on the edge of the negative electrode can, and the leakage resistance was evaluated. Table 2 shows the results.

(Comparative Example 5)
In Comparative Example 2, the rubber sealant solution 1 prepared in Production Example 1 was used in place of the asphalt sealant solution produced in Production Example 3 to form a rubber sealant layer with a thickness of 3 μm on the resin gasket. A silver oxide battery was produced in the same manner as in Comparative Example 2 except that the was formed, and the leakage resistance was evaluated. Table 2 shows the results.

From the results in Table 2, the sealant layer has a two-layer structure of a rubber-based sealant layer and an asphalt-based sealant layer, and the rubber-based sealant layer is positioned on the negative electrode can side, and the asphalt-based sealant layer It can be seen that the silver oxide batteries of Examples 1 and 2, in which the layer is located on the side of the resin gasket, are excellent in leakage resistance and can extend the life of the battery.
On the other hand, from the results in Table 2, the silver oxide batteries of Comparative Examples 1 and 4, in which the sealant layer had a single-layer structure of an asphalt-based sealant layer or a rubber-based sealant layer, even if the sealant layer had a two-layer structure, , the silver oxide batteries of Comparative Examples 2 and 3 in which each layer is the same, and even if the sealing agent layer has a two-layer structure, the rubber-based sealing agent layer and the asphalt-based sealing agent layer on the negative electrode can side and the resin gasket side It can be seen that the silver oxide battery of Comparative Example 5, in which the .

According to the present invention, it is possible to provide a long-life silver oxide battery.

1 positive electrode can 10 silver oxide battery 2 positive electrode 3 separator 4 resin gasket 5 sealant layer 5a rubber-based sealant layer 5b asphalt-based sealant layer 6 negative electrode 7 negative electrode can

Claims (5)

A silver oxide battery containing a positive electrode, a negative electrode, a separator and an electrolytic solution in a battery container,
The battery container is formed by joining a positive electrode can and a negative electrode can via a resin gasket and a sealant layer provided on the negative electrode can side of the resin gasket,
The silver oxide battery, wherein the sealant layer includes a layer of a rubber-based sealant located on the negative electrode can side, and a layer of an asphalt-based sealant located on the resin gasket side. 2. The silver oxide battery according to claim 1, wherein said rubber sealant contains a rubber polymer having a glass transition temperature of 0[deg.] C. or less. 3. The silver oxide battery of claim 1 or 2, wherein the asphalt-based sealant comprises blown asphalt. The silver oxide battery according to any one of claims 1 to 3, wherein the resin gasket is made of nylon 66. 5. The silver oxide battery according to claim 1, wherein the surface of said negative electrode can that comes into contact with said sealant layer is made of copper.

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