JP5116140B2 - Flat silver oxide battery - Google Patents

Description

  The present invention relates to a flat silver oxide battery excellent in load characteristics.

  A flat silver oxide battery including a positive electrode having silver oxide, a negative electrode having zinc or a zinc alloy, and an alkaline electrolyte is widely used as a drive power source for various electronic devices. With higher functionality, there is an increasing demand for improved load characteristics for flat silver oxide batteries used in such devices.

  As a technique that meets such a demand, Patent Document 1 proposes a coin-type silver oxide battery using a negative electrode having zinc particles containing fine particles or zinc alloy particles.

JP 2006-173048 A

  Since the coin-type silver oxide battery disclosed in Patent Document 1 has good heavy-load discharge characteristics, it can meet the demand for improved load characteristics required for recent flat-type silver oxide batteries. .

  However, in a battery having silver oxide as a positive electrode, when discharging is performed under a heavy load, there is a problem that the voltage decreases at the initial stage of discharge. For example, as disclosed in Patent Document 1, this problem cannot be solved sufficiently even if fine particles of zinc particles or zinc alloy particles are used for the negative electrode. The technology still has room for improvement.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a flat silver oxide battery excellent in load characteristics and capable of suppressing a voltage drop at the initial stage of discharge.

  The flat silver oxide battery of the present invention that has achieved the above-mentioned object comprises a positive electrode, a negative electrode containing zinc particles or zinc alloy particles, a separator, and an electrolyte solution in a battery container comprising an outer can, a sealing plate, and a resin gasket. The positive electrode contains silver oxide and a silver-nickel composite oxide, and the negative electrode contains zinc particles or zinc alloy particles (hereinafter referred to as zinc particles and zinc alloy particles). Are sometimes referred to as “zinc-based particles”), and particles capable of passing through a 200-mesh sieve are 10% by mass or more.

  In the present invention, a silver-nickel composite oxide is used together with silver oxide to form a positive electrode, and the negative electrode is formed using zinc-based particles containing fine particles as described above, thereby providing a heavy load in a silver oxide battery. This suppresses the voltage drop at the beginning of discharge, which was a problem at the time of discharge. Therefore, the flat silver oxide battery of the present invention can stabilize the discharge voltage.

  Moreover, the electroconductivity of a positive electrode can be made favorable and the reactivity can be improved by adding silver-nickel complex oxide to a positive electrode. On the other hand, also in the negative electrode, by using the zinc-based particles containing fine particles as described above, the surface area of the negative electrode can be increased and the reactivity thereof can be increased. Therefore, in the flat silver oxide battery of the present invention, the reactivity improvement effect of the positive electrode and the reactivity improvement effect of the negative electrode are functioned synergistically to ensure excellent load characteristics.

  In the battery industry, a flat battery with a diameter larger than the height is called a coin-type battery or a button-type battery, but there is a clear gap between the coin-type battery and the button-type battery. There is no difference, and the flat silver oxide battery of the present invention includes what is called a coin-type battery and what is called a button-type battery.

  ADVANTAGE OF THE INVENTION According to this invention, the flat type silver oxide battery which was excellent in the load characteristic and was able to suppress the voltage drop at the beginning of discharge can be provided.

  1 and 2 schematically show an example of the flat silver oxide battery of the present invention. FIG. 1 is a side view, 1 is a flat silver oxide battery, 2 is an outer can, and 3 is a sealing plate.

  FIG. 2 is a schematic diagram showing an example of a cross section of the main part of FIG. The flat silver oxide battery 1a is made of an annular resin having an L-shaped cross section in which a sealing plate 3 having a negative electrode 5 embedded in an opening of an outer can 2 having a positive electrode (positive electrode molded body) 4 and a separator 6 embedded therein. The opening of the outer can 2 is clamped inward by the gasket 7, and the resin gasket 7 abuts against the sealing plate 3, thereby sealing the opening of the outer can 2. The inside of the battery has a sealed structure. That is, in the flat silver oxide battery 1a of FIG. 2, a power generation element including the positive electrode 4, the negative electrode 5, and the separator 6 in the space (sealed space) in the battery container composed of the outer can 2, the sealing plate 3, and the resin gasket 7. And an electrolyte (not shown) is further injected. The outer can 2 also serves as a positive terminal, and the sealing plate 3 also serves as a negative terminal.

  FIG. 3 schematically shows a cross section of the main part of another example of the flat silver oxide battery of the present invention. In FIG. 3, elements having the same functions are denoted by the same reference numerals as those in FIGS. 1 and 2 (the same applies to FIG. 4 described later).

  The flat silver oxide battery 1b shown in FIG. 3 is a battery that employs a so-called bottom structure, and the outer peripheral portion of the positive electrode (positive electrode molded body) 4 is disposed between the inner bottom surface of the outer can 2 and the resin gasket 7. Has been.

  In the case of the flat silver oxide battery 1a shown in FIG. 2, since the resin gasket 7 has reached the bottom of the outer can 2, the occupied volume of the gasket 7 that is not involved in power generation out of the internal volume of the battery. It is large and hinders high capacity. On the other hand, in the flat silver oxide battery 1b shown in FIG. 3, the bottom structure is adopted and the positive electrode 4 is arranged up to the lower part of the gasket 7, so that the filling amount of the positive electrode in the battery can be increased. This is possible, and the battery can have a higher capacity.

  Examples of the material of the outer can 2 include stainless steel and nickel-plated iron.

  As the sealing plate 3, for example, the surface in contact with the negative electrode 5 is made of a copper alloy such as copper or brass, the main body portion is made of stainless steel, and the outer surface side, that is, the surface opposite to the surface in contact with the negative electrode 5 is Those composed of nickel are preferred. In this sealing plate 3, it is preferable that the surface in contact with the negative electrode 5 is made of copper or a copper alloy because formation of a local battery with zinc can be suppressed. However, the main body portion can be made of stainless steel. The outer surface side is not necessarily made of nickel, and may be made of other materials. If the surface in contact with the negative electrode 5 does not form a local battery with zinc, it is not made of copper or a copper alloy. Also good.

  As the resin gasket 7, for example, a material made of nylon 66 or the like is recommended.

  The shape of the battery of the present invention is not particularly limited as long as it belongs to a so-called flat battery, and may be a circle in plan view, a square such as a square, or a polygon more than a pentagon. In the case of a polygon in plan view, the corner may be cut off, or the corner may be a curve.

  Next, components of the flat silver oxide battery of the present invention will be described.

<Negative electrode>
The negative electrode according to the present invention has zinc particles or zinc alloy particles. The zinc component in these zinc-based particles acts as a negative electrode active material.

  As an alloy component of the zinc alloy particles, for example, mercury (for example, the content is 1 to 5 mass%), indium (for example, the content is 50 to 500 mass ppm), bismuth (for example, the content is 50 to 500 mass). ppm) and the like (the balance being zinc and inevitable impurities). The zinc-based particles possessed by the negative electrode may be one type alone or two or more types.

  In the negative electrode according to the present invention, among the zinc-based particles, those that can pass through a 200 mesh sieve are 10% by mass or more, preferably 30% by mass or more, and more preferably 50% by mass or more. Thus, when the zinc-based particles possessed by the negative electrode are small, the specific surface area of the entire negative electrode can be increased and the reaction at the negative electrode can be advanced efficiently, so the load characteristics (particularly heavy load characteristics) of the battery are good. It becomes.

  From the viewpoint of reducing the size of the zinc-based particles possessed by the negative electrode and further improving the reaction efficiency at the negative electrode, the proportion of the zinc-based particles possessed by the negative electrode that can pass through a 330 mesh sieve is 10 The content is preferably at least mass%, more preferably at least 30 mass%. In addition, since the handleability falls when the size of the zinc-based particle which the negative electrode has is too small, for example, the minimum size of the zinc-based particle which the negative electrode has is desirably about 1 μm.

  The zinc-based particles are more preferably those that do not contain mercury or those that do not contain lead. If it is a battery using such zinc-based particles, for example, when it is used for power supply of an endoscope camera of a type swallowed from the mouth, observed inside the body for a certain period of time, and then discharged out of the body In addition, even if zinc or the like inside the battery leaks in the human body, adverse effects on the human body can be minimized, and environmental pollution due to battery disposal can also be suppressed.

  The negative electrode includes, for example, a gelling agent (sodium polyacrylate, carboxymethylcellulose, etc.) added as necessary in addition to the zinc-based particles, and is configured by adding an alkaline electrolyte thereto. A negative electrode agent (gelled negative electrode) can be applied. The amount of the gelling agent in the negative electrode is preferably 0.5 to 1.5% by mass, for example.

  The negative electrode can also be a non-gelled negative electrode that does not substantially contain the gelling agent as described above (in the case of a non-gelled negative electrode, the electrolyte present in the vicinity of the zinc-based particles is thickened). Therefore, “substantially no gelling agent” means that it may be contained to the extent that it does not affect the electrolyte viscosity). In the case of a gelled negative electrode, an electrolyte solution is present together with the gelling agent in the vicinity of the zinc-based particles, but this electrolyte solution is thickened by the action of the gelling agent, and the electrolyte solution moves. The movement of ions in the electrolyte is suppressed. For this reason, the reaction rate at the negative electrode is suppressed, which is considered to impede improvement of the heavy load characteristics of the battery. On the other hand, by making the negative electrode non-gel, keeping the ion moving rate in the electrolytic solution high without increasing the viscosity of the electrolytic solution present in the vicinity of the zinc-based particles, increasing the reaction rate at the negative electrode, The heavy load characteristics can be improved.

<Positive electrode>
The positive electrode according to the present invention includes an active material such as silver oxide (first silver oxide, second silver oxide, etc.) and a silver-nickel composite oxide, and a conductive additive made of carbonaceous material such as carbon black, graphite, and graphite. A positive electrode molded body produced by press-molding the mixed powder (positive electrode mixture) into a pellet (such as a disk) is applied.

  The silver oxide used for the positive electrode may be, for example, a fine powder having a diameter of 0.1 to 5 μm that is normally distributed, but it is in the form of granules obtained by granulating such fine powder of silver oxide. Those are more preferred. When granular silver oxide is used, the resistance is lower than when it is used in the form of fine powder, so that the load characteristics of the flat silver oxide battery can be further improved.

  When silver oxide is used in a fine powder state as in the past, it is necessary to add a large amount of conductive aid to reduce resistance, but the carbonaceous material used as the conductive aid has a bulk density. Since it is small, if it is added in a large amount, it becomes difficult to increase the filling amount of silver oxide as an active material. On the other hand, when granular silver oxide is used, weighability is improved and variation is reduced, and when press molding is performed, filling property is increased and moldability is improved, so that resistance is reduced, When a plurality of positive electrodes (and thus silver oxide batteries) are manufactured, individual characteristics are stabilized. Furthermore, the amount of carbonaceous material added as a conductive aid can be reduced to about half, for example, and the amount of silver oxide filled can be increased.

Furthermore, for example, in the case of silver oxide, the discharge performance is deteriorated because it is reduced by causing a reaction such as the following formula with carbonaceous matter.
2Ag ₂ O + C → 4Ag + CO ₂

  However, by making silver oxide into granules, the above reaction can be suppressed, and the amount of carbonaceous addition can be reduced as described above, so that the reduction reaction of silver oxide is further suppressed, and the discharge characteristics. A decrease in (especially low temperature heavy load characteristics) can be suppressed.

The particle size of the granular silver oxide is preferably 50 μm or more, more preferably 75 μm or more, and 500 μm or less, more preferably 300 μm or less. The bulk density of the granular silver oxide is 1.5 g / cm ³ or more, more preferably 1.8 g / cm ³ or more, and 3.5 g / cm ³ or less, more preferably 2.6 g / cm ^3. It is recommended that: If the silver oxide in such a form, the flowability is better than that in the powder form, and as described above, the weighability and moldability are improved, the resistance is lowered and the reactivity is improved. The load characteristics are excellent, and the characteristics of the produced positive electrode (and thus the silver oxide battery) are stabilized. In addition, the particle diameter of granular silver oxide as used in the present specification is determined by the number of particles n and the diameter d of each particle by scattering of laser light using a microtrack particle size distribution meter “9320-X100” manufactured by Honeywell. The number average particle diameter measured and calculated. Further, the bulk density of granular silver oxide referred to in the present specification is determined using a bulk density measuring device by placing a predetermined amount of granular silver oxide in a container in accordance with the bulk density measuring method specified in JIS R 1628. Value.

  In the battery of the present invention, a silver-nickel composite oxide is used together with silver oxide for the positive electrode. In a battery using silver oxide as a positive electrode active material, there is a problem that a voltage drop occurs at the initial stage of discharge at heavy load, but a positive electrode containing a silver-nickel composite oxide and zinc containing the above fine particles By using together with the negative electrode having the system particles, a silver oxide battery capable of discharging at a stable voltage can be obtained while suppressing a voltage drop at the initial stage of discharge. This is because silver (Ag) having high conductivity is generated from the silver-nickel composite oxide in accordance with the discharge reaction of the battery, and this silver functions as a conductive additive in the positive electrode (positive electrode molded body). This is not because the discharge reaction proceeds more smoothly by the combined use of such a positive electrode and a zinc-based particle containing fine particles and a highly reactive negative electrode. It is thought.

  Moreover, since the reactivity of a positive electrode is improved by use of silver-nickel composite oxide, the load characteristic of a battery is also improved. Therefore, a battery having excellent load characteristics can be obtained by using a positive electrode containing a silver-nickel composite oxide and a negative electrode having zinc-based particles containing the fine particles.

  In addition, in a battery using zinc or a zinc alloy for the negative electrode, zinc is easily corroded by the electrolytic solution during storage, and gas (hydrogen gas) is easily generated. When the amount of gas in the battery increases, the battery swells. There is a risk that it may occur or leakage of the electrolyte solution outside the battery may occur. When zinc-based particles containing fine particles are used as in the battery of the present invention, the above problem due to gas generation in the battery is more likely to occur. However, in the battery of the present invention, the hydrogen gas generated inside the battery can be oxidized into water by the silver-nickel composite oxide contained in the positive electrode, so that battery swelling and leakage due to hydrogen gas occur. And the reliability of the battery can be improved.

  As shown in FIG. 3, in the case of a battery with a bottom structure, the capacity of the battery can be increased. However, in comparison with the positive electrode molded body applied to the battery having the structure shown in FIG. The thickness with respect to the area is reduced. FIG. 4 is a side view showing another example of the flat silver oxide battery of the present invention. As shown in the flat silver oxide battery 10 shown in FIG. In addition, although it is possible to increase the opposing area between the positive electrode and the negative electrode by further reducing the thickness and thereby further improving the load characteristics of the battery, The thickness with respect to the area in plan view becomes small. As described above, since the positive electrode molded body having a small thickness with respect to the area in plan view is insufficient in strength and easily cracks, a battery using such a positive electrode molded body has, for example, positive electrode conductivity. It may be lost and the original capacity may not be achieved. Since cracking of the positive electrode molded body is likely to occur at the time of tightening when sealing the outer can and the sealing plate, it is conceivable to suppress the tightening strength and prevent cracking of the positive electrode molded body. May cause a leakage due to insufficient sealing strength.

  However, in the battery according to the present invention, since the silver-nickel composite oxide is contained in the positive electrode, and thereby the strength of the positive electrode molded body can be increased, the positive electrode molded body has a thickness with respect to the area in plan view. Even if the shape is very small, it is possible to prevent the cracking, suppress the decrease in the conductivity of the molded positive electrode in the battery, and more effectively draw out the capacity of the battery.

  In addition, in a battery that uses zinc or the like as a negative electrode and uses an alkaline electrolyte as an electrolytic solution, a manganese-containing oxide such as manganese dioxide is also known as a positive electrode active material, but in a positive electrode according to the present invention, It is preferable not to contain a manganese-containing oxide. In that case, the strength of the positive electrode molded body can be further increased, and the occurrence of the above-described cracks can be suppressed more favorably.

The silver-nickel composite oxide to be contained in the positive electrode is preferably represented by the general formula Ag _X Ni _Y O ₂ and X / Y is greater than 1 and 1.9 or less. In the specific silver-nickel composite oxide, Ag is more excessively incorporated into the crystal than AgNiO ₂ which is widely used as the silver-nickel composite oxide. Therefore, the electroconductivity and moldability (positive electrode molded body strength) of the positive electrode can be improved as compared with the case of using AgNiO ₂ .

The silver-nickel composite oxide represented by the general formula Ag _X Ni _Y O ₂ and having X / Y greater than 1 and 1.9 or less, for example, oxidizes Ag salt of inorganic acid and Ni salt of inorganic acid. It can manufacture by making it react in basic alkaline aqueous solution.

  Specifically, for example, an Ag salt of an inorganic acid and an Ni salt of an inorganic acid are neutralized with an alkali metal hydroxide in water, and before the neutralization reaction, during the neutralization reaction, or the neutralization reaction After the reaction, an oxidizing agent is added to the reaction solution to carry out an oxidation treatment. It is preferable to add the oxidizing agent a plurality of times before, during or after the neutralization reaction.

Examples of the inorganic acid Ag salt include silver hydrochloride, silver nitrate, silver sulfate, and silver phosphate. Examples of Ni salts of inorganic acids include nickel hydrochloride, nickel nitrate, nickel sulfate, and nickel phosphate. Further, examples of the alkali metal hydroxide include potassium hydroxide and sodium hydroxide. Examples of the oxidizing agent include KMnO ₄ , K ₂ S ₂ O ₈ , NaOCl, Na ₂ S ₂ O ₈ , H ₂ O ₂ , and ozone.

  In the above neutralization reaction, it is preferable to increase the alkalinity in the reaction solution. For example, the molar amount of Ag in the Ag salt of the inorganic acid and the molar amount of Ni in the Ni salt of the inorganic acid. The molar amount of the alkali metal hydroxide is preferably about 5 times the total amount. In addition, the amount of the oxidizing agent used is preferably equal to or greater than the oxidation, that is, the valence change of the metal ion, and more preferably about twice the equivalent.

  The temperature during the neutralization reaction and oxidation treatment is preferably, for example, between room temperature and 100 ° C. (more preferably 30 to 50 ° C.). The neutralization reaction and the oxidation treatment are preferably performed while stirring the reaction solution.

  After the oxidation treatment, the generated reaction precipitate is separated from the reaction solution, and the collected reaction precipitate is washed with water, dried, and crushed as necessary to obtain the specific silver-nickel composite oxide. .

  From the viewpoint of more effectively exerting the above-mentioned various actions (particularly, the action of suppressing the voltage drop at the initial stage of discharge of the battery) due to the use of the silver-nickel composite oxide, The content is preferably 20% by mass or more, and more preferably 30% by mass or more. If the amount of the silver-nickel composite oxide in the positive electrode molded body is too large, a large amount of silver-nickel composite oxide will be dissolved in the electrolyte, and the silver ions generated thereby react with the zinc in the negative electrode to self Since there is a risk of causing discharge and a decrease in the discharge capacity of the battery, the content of the silver-nickel composite oxide in the positive electrode compact is preferably 70% by mass or less, and 50% by mass or less. It is more preferable.

  Moreover, in a positive electrode molded object, it is preferable that content of an active material (silver oxide and silver-nickel composite oxide) is 90-99 mass%, and a conductive support agent is 1-10 mass%.

  Although there is no restriction | limiting in particular about the thickness of a positive electrode molded object, For example, the thickness may be 0.25 mm or less, and generation | occurrence | production of the crack of a positive electrode molded object can be suppressed also in such a case. However, if the positive electrode molded body is too thin, it may be difficult to suppress the occurrence of cracks, and thus the thickness is preferably 0.2 mm or more.

<Electrolyte>
In the flat silver oxide battery of the present invention, an alkaline aqueous solution is used as the electrolytic solution. As the alkali, alkali metal hydroxides (sodium hydroxide, potassium hydroxide, lithium hydroxide, etc.) are preferably used, and potassium hydroxide is particularly preferred. For example, in the case of an aqueous solution of potassium hydroxide, the concentration of the electrolytic solution is 20% by mass or more, more preferably 30% by mass or more, and 40% by mass or less, more preferably 38% by mass or less. Desirably, by adjusting the concentration of the aqueous solution to such a value, an electrolytic solution having excellent conductivity can be obtained.

  In addition to the above-described components, various known additives may be added to the electrolytic solution as necessary within a range not impairing the effects of the present invention. For example, zinc oxide may be added to prevent corrosion (oxidation) of zinc-based particles used for the negative electrode of a silver oxide battery.

<Separator>
The separator in the battery of the present invention is not particularly limited. For example, non-woven fabric mainly composed of vinylon and rayon, vinylon / rayon nonwoven fabric (vinylon / rayon mixed paper), polyamide nonwoven fabric, polyolefin / rayon nonwoven fabric, vinylon paper, vinylon linter Pulp paper, vinylon mercerized pulp paper, or the like can be used. A hydrophilic microporous polyolefin film (microporous polyethylene film, microporous polypropylene film, etc.), cellophane film, and liquid absorbing layer (electrolyte holding layer) such as vinylon / rayon mixed paper were stacked. It is good also as a separator.

  Since the flat silver oxide battery of the present invention has good load characteristics and stable voltage during discharge, an electronic device that requires discharge under heavy load by taking advantage of such characteristics It can be used for various uses to which a conventionally known silver oxide battery is applied, such as a power source use (for example, a capsule endoscope camera).

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples are not intended to limit the present invention, and all modifications made without departing from the spirit of the preceding and following descriptions are included in the technical scope of the present invention.

Example 1
As a positive electrode active material, a mixture containing 70% by mass of primary silver oxide (Ag ₂ O) and 30% by mass of silver-nickel composite oxide (Ag _1.05 Ni _0.95 O ₂ ) is pressure-molded. Then, this compact was pulverized and sieved to prepare a mixture of primary silver oxide and silver-nickel composite oxide in the form of granules having an average particle size of 150 μm and a bulk density of 2.0 g / cm ³ . For the positive electrode, 2 parts by mass of scaly graphite as a conductive additive was added to the granulation mixture with respect to 100 parts by mass of the granulation mixture (positive electrode active material) and mixed to obtain a positive electrode mixture. This positive electrode mixture was pressure-molded into a pellet shape having a packing density of 6 g / cm ³ , a diameter of 8.9 mm, and a height of 0.4 mm to produce a positive electrode molded body, and a portion of the alkaline electrolyte was added thereto. Was impregnated.

  As the negative electrode, 36 mg of zinc particles having a ratio of particles capable of passing through a 200 mesh sieve was 95% by mass.

  As the alkaline electrolyte, a 36% by mass potassium hydroxide aqueous solution in which 5% by mass of zinc oxide was dissolved was used. Moreover, the exterior can was produced using SUS430. Furthermore, the sealing plate was produced using a copper-stainless steel (SUS304) -nickel clad plate. In addition, “YG9132” from Yuasa Membrane System Co., Ltd. was used as the separator. This separator is formed by laminating a cellophane film having a thickness of 20 μm and a graft film having a thickness of 30 μm. The graft film has a structure in which a polyethylene main chain is graft copolymerized with acrylic acid. It is composed of a polymer. Further, a vinylon-rayon mixed paper having a thickness of 200 μm was used as the electrolytic solution holding layer. The separator and the electrolyte solution holding layer were used by punching into a circle having a diameter of 9.3 mm.

  Using the above positive electrode, negative electrode, alkaline electrolyte, outer can, sealing plate, separator and electrolyte holding layer, and further using an annular gasket made of nylon 66, the structure shown in FIG. 2 has a diameter of 9.5 mm and a thickness of A 1.6 mm coin-shaped silver oxide battery was produced. In FIG. 2, the electrolyte solution holding layer is not shown, but in the battery of Example 1, the electrolyte solution holding layer was disposed on the upper surface side (the negative electrode 5 side) of the separator 6.

Example 2
The positive electrode active material was changed to a mixture containing 90% by mass of primary silver oxide (Ag ₂ O) and 10% by mass of silver-nickel composite oxide (Ag _1.05 Ni _0.95 O ₂ ). Produced a coin-type silver oxide battery in the same manner as in Example 1.

Example 3
The positive electrode active material was changed to a mixture containing 50% by mass of primary silver oxide (Ag ₂ O) and 50% by mass of silver-nickel composite oxide (Ag _1.05 Ni _0.95 O ₂ ). Produced a coin-type silver oxide battery in the same manner as in Example 1.

Comparative Example 1
A coin-type silver oxide battery was produced in the same manner as in Example 1 except that the positive electrode active material used was pressure-molded with silver oxide alone.

  For each battery of Examples 1 to 3 and Comparative Example 1, the following load characteristic evaluation was performed. For each battery of Examples 1 to 3 and Comparative Example 1, continuous discharge was performed at 20 ° C. with a discharge current of 10 mA and a final voltage of 1.2 V, and the closed circuit voltage and discharge capacity after 5 seconds from the start of discharge were measured. did. These results are shown in Table 1.

  As can be seen from Table 1, the silver oxide batteries of Examples 1 to 3 have a higher voltage 5 seconds after the start of discharge than the battery of Comparative Example 1, and the voltage drop at the beginning of discharge is suppressed. The discharge capacity is large and the load characteristics are excellent even when discharging at 10 mA with a relatively large load.

It is a side view which shows typically an example of the flat type silver oxide battery of this invention. It is a schematic diagram which shows an example of the principal part cross section of the flat silver oxide battery of FIG. It is a schematic diagram which shows the other example of the principal part cross section of the flat silver oxide battery of FIG. It is a side view which shows typically the other example of the flat silver oxide battery of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b, 10 Flat shape silver oxide battery 2 Outer can 3 Sealing plate 4 Positive electrode molded object 5 Negative electrode 6 Separator 7 Resin gasket

Claims (7)

A flat silver oxide battery comprising a positive electrode, a negative electrode containing zinc particles or zinc alloy particles, a separator, and an electrolytic solution housed in a battery container composed of an outer can, a sealing plate, and a resin gasket,
The positive electrode contains silver oxide and a silver-nickel composite oxide,
A flat silver oxide battery characterized in that among the zinc particles or zinc alloy particles contained in the negative electrode, the particles capable of passing through a 200 mesh sieve are 10% by mass or more.   2. The flat silver oxide battery according to claim 1, wherein among the zinc particles or zinc alloy particles contained in the negative electrode, 30% by mass or more of particles that can pass through a 200-mesh sieve are provided.   3. The flat silver oxide battery according to claim 1, wherein among the zinc particles or zinc alloy particles contained in the negative electrode, the particles capable of passing through a 200 mesh sieve are 50% by mass or more.   The flat silver oxide battery according to any one of claims 1 to 3, wherein among the zinc particles or zinc alloy particles contained in the negative electrode, the particles capable of passing through a 330 mesh sieve are 10% by mass or more.   The flat silver oxide battery according to any one of claims 1 to 4, wherein among the zinc particles or zinc alloy particles contained in the negative electrode, 30 mass% or more of the particles can pass through a mesh of 330 mesh. The flat silver oxide battery according to claim 1, wherein the silver-nickel composite oxide is represented by a general formula Ag _X Ni _Y O ₂ , and X / Y is greater than 1 and 1.9 or less.   The flat silver oxide battery according to any one of claims 1 to 6, wherein the positive electrode does not contain a manganese-containing oxide.

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