JPH11167933A - Sealed alkaline zinc storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alkaline zinc storage battery with less self discharging and moreover with less capacity drop during short cycles. SOLUTION: A sealed alkaline zinc storage battery has a positive electrode, using manganese dioxide or nickel oxyhydroxide as the positive active material and a gelled negative electrode prepared by dispersing a zinc alloy of zinc and at least one element selected from the group comprising indium, bismuth, calcium, aluminum, tin, and gallium, having an atomic ratio of 100:0.05 to 100:2.0, in an alkaline electrolyte. The gelled negative electrode contains 5-40 wt.% zinc oxide based on the weight of the zinc alloy, 0.05-5 atomic percent rare-earth element and/or rare-earth element compound; based on the weight of zinc oxide and zinc in the zinc alloy, and 75 vol.% or more manganese dioxide or nickel oxyhydroxide, zinc alloy, and rareearth element and/or rare-earth element compound based on the total volume of a battery can are filled in the battery case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge-starting sealed alkaline zinc storage battery, and more particularly, to a discharge-starting sealed alkaline zinc storage battery in which self-discharge is small and the battery capacity is not greatly reduced in a short cycle. The present invention relates to an improvement of a negative electrode active material for the purpose of doing so. Here, the discharge-started battery is a battery that can be discharged for the first time without being charged.

[0002]

2. Description of the Related Art When zinc metal is used as a negative electrode active material of an alkaline zinc battery,
During storage, there is a problem that zinc reacts with the alkaline electrolyte to corrode. For this reason, in a conventional practical battery, zinc corrosion during storage (self-discharge; Zn + 2H ₂ O → Zn ⁺² +
In order to suppress 2OH ⁻ + H ₂ ), zinc calomel obtained by adding mercury having a high hydrogen overvoltage to zinc by several% is used as a negative electrode active material.

However, in recent years, there has been a demand for mercury-free negative electrode active materials in order to reduce the pollution of alkaline zinc batteries, and various proposals have been made to meet this demand.

For example, a low-corrosive zinc alloy containing at least one element selected from the group consisting of indium, lead, bismuth, calcium, aluminum and lithium is used as a negative electrode active material, and an aromatic amine (Sulfanilic acid, etc.), an inorganic inhibitor (yttrium oxide or gallium oxide or a hydrate thereof), and an organic inhibitor (fluorinated surfactant) have been proposed to be added (Japanese Patent Laid-Open No. Hei 5-205). 24289
No. 5).

According to this method, corrosion of zinc, that is, self-discharge can be suppressed despite the fact that the mercury content is 0 (zero).

However, as a result of studies by the present inventors, the above zinc alloy has no problem when it is used for a dry battery, but when it is used for a storage battery that repeats charging and discharging, the use of the active material of the negative electrode in a short cycle is reduced. Rate, and as a result,
It has been found that the battery capacity originally regulated by the positive electrode capacity decreases before being regulated by the negative electrode capacity.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a sealed alkaline zinc storage battery having a small self-discharge and a discharge start in which the battery capacity is not greatly reduced in a short cycle.

[0008]

A sealed alkaline zinc storage battery according to the present invention (hereinafter referred to as "battery of the present invention") is provided.
A positive electrode having manganese dioxide or nickel oxyhydroxide as a positive electrode active material, an atomic ratio of zinc and at least one element selected from the group consisting of indium, bismuth, calcium, aluminum, tin and gallium of 100: 0.0
A sealed alkaline zinc storage battery comprising: a gelled negative electrode obtained by dispersing a 5-100: 2.0 zinc alloy in an alkaline electrolyte; wherein the gelled negative electrode has a zinc oxide to zinc alloy ratio. 5 to 40% by weight, and 0.05 to 5 atomic% of rare earth element and / or rare earth element compound in a ratio of rare earth element to zinc in zinc oxide and zinc alloy.
Containing 75% by volume of manganese dioxide or nickel oxyhydroxide, zinc alloy, zinc oxide and rare earth element and / or rare earth element
It is characterized by being filled as described above.

The battery of the present invention comprises a positive electrode comprising manganese dioxide or nickel oxyhydroxide as a positive electrode active material; zinc; and at least one element selected from the group consisting of indium, bismuth, calcium, aluminum, tin and gallium. And a gelled negative electrode obtained by dispersing a zinc alloy having an atomic ratio of 100: 0.05 to 100: 2.0 in an alkaline electrolyte. If the ratio of the other alloying elements to zinc in the zinc alloy is too small, the hydrogen overvoltage cannot be sufficiently increased, and zinc corrosion, that is, self-discharge cannot be effectively suppressed. On the other hand, when the ratio of the other alloying element to zinc is too large, the charge / discharge reaction of zinc is inhibited by the other alloying element, and the battery capacity is reduced.

The gelled negative electrode of the battery of the present invention contains 5 to 40% by weight of zinc oxide relative to a zinc alloy, and contains a rare earth element or a rare earth element compound in a ratio of zinc oxide and a rare earth element to zinc in the zinc alloy. It contains 0.05 to 5 atomic%. When the ratio of zinc oxide to the zinc alloy is less than 5% by weight, the charge reserve is not sufficiently generated in the negative electrode, so that the reduction of the active material utilization rate due to the deterioration of the zinc alloy with the progress of the charge / discharge cycle is sufficiently reduced. It cannot be suppressed, and the battery capacity decreases in a short cycle. On the other hand, when the ratio of zinc oxide to the zinc alloy exceeds 40% by weight, the filling amount of the zinc alloy as the negative electrode active material decreases, and the battery capacity decreases. On the other hand, when the ratio of the rare earth element to zinc is less than 0.05 atomic%, zinc oxide generated on the surface of the zinc alloy particles at the time of discharge cannot be sufficiently made porous, so that the charge / discharge cycle proceeds. The accompanying decrease in the active material utilization cannot be effectively suppressed. On the other hand, when the ratio of the rare earth element to zinc exceeds 5 atomic%, the filling amount of the zinc alloy and zinc oxide is reduced.
It is not possible to effectively suppress a decrease in the active material utilization rate due to the deterioration of the zinc alloy accompanying the progress of the charge / discharge cycle.

The battery of the present invention is limited to a sealed battery in which the filling rate of manganese dioxide or nickel oxyhydroxide, a zinc alloy, zinc oxide, a rare earth element and / or a rare earth element compound with respect to the internal volume of the battery can is 75% by volume or more. Is
This is because the effect of the present invention is remarkably exhibited in this type of battery filled with a large amount of active material.

Since the battery of the present invention uses a low-corrosive zinc alloy as the negative electrode active material, self-discharge during storage is small. Further, in the battery of the present invention, the zinc alloy and the rare earth element and / or the rare earth element compound are added in predetermined amounts to the zinc alloy, respectively, so that the decrease in the active material utilization rate with the progress of the charge / discharge cycle is small, Battery capacity does not decrease significantly in a short cycle.

[0013]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples, and the present invention may be practiced by appropriately changing the gist of the invention. Is possible.

(Experiment 1) In this experiment, the batteries A to
U and a conventional battery X (battery disclosed in JP-A-5-242895) were prepared, and each battery was charged and discharged for 30 cycles, and the discharge capacity at the first cycle and the 30th cycle was examined.

(Batteries A to U of the Present Invention) [Preparation of Positive Electrode] 90 g of nickel oxyhydroxide, 10 g of graphite as a conductive agent, and 10 g of a 30% by weight aqueous potassium hydroxide solution were mixed for 30 minutes by a grinder. Then, pressure molding is performed, and the outer diameter is 1.3 cm, the inner diameter is 0.85 cm, and the height is 1.
A 15 cm cylindrical hollow body-shaped positive electrode was produced. In the production of the battery, three cylindrical hollow body-shaped positive electrodes were prepared, and these were stacked in series, and used as a single cylindrical hollow body-shaped positive electrode as a whole.

[Preparation of Negative Electrode] 100 g of zinc and 0.57 g of indium (atomic ratio of zinc to indium of 100: 0.
5) was melted at 500 ° C. to prepare a melt, and the melt was cooled by an atomizing method to prepare a zinc alloy powder having an atomic ratio of zinc to indium of 100: 0.5. 100 g of this zinc alloy powder, 10 g of zinc oxide, 1.13 g of yttrium oxide (Y ₂ O ₃ ), 0.690 g of scandium oxide (Sc ₂ O ₃ ), and lanthanum oxide (La ₂ O)
₃ ) 1.63 g, cerium oxide (CeO ₂ ) 3.12
g, praseodymium oxide (Pr ₆ O ₁₁ ) 1.70 g, neodymium oxide (Nd ₂ O ₃ ) 1.68 g, promethium oxide (Pm ₂ O ₃ ) 1.69 g, samarium oxide (Sm ₂ O)
₃ ) 1.74 g, europium oxide (Eu ₂ O ₃ )
76 g, gadolinium oxide (Gd ₂ O ₃ ) 1.81 g,
1.87 g of terbium oxide (Tb ₄ O ₇ ), 1.87 g of dysprosium oxide (Dy ₂ O ₃ ), 1.89 g of holmium oxide (Ho ₂ O ₃ ), erbium oxide (Er ₂ O)
₃ ) 1.91 g, thulium oxide (Tm ₂ O ₃ ) 1.93
g, ytterbium oxide (Yb ₂ O ₃ ) 1.97 g, ruthenium oxide (Lu ₂ O ₃ ) 1.99 g, yttrium hydroxide (Y (OH) ₃ ) 1.40 g, yttrium fluoride (YF ₃ ) 1.46 g , 2.06 g of yttrium carbonate trihydrate (Y ₂ (CO ₃ ) ₃ .3H ₂ O) or 0.89 g of metal yttrium (Y), and a 40% by weight aqueous solution of potassium hydroxide was added to the resulting mixture. 34 g and 1 g of polyacrylic acid (manufactured by Nippon Junyaku Kogyo Co., Ltd., product code "Junron PW150") as a gelling agent were mixed and stirred, containing 10% by weight of zinc oxide relative to a zinc alloy, containing rare earth elements. Element or rare earth element compound is 1 atomic% in the ratio of rare earth element to zinc in zinc oxide and zinc alloy.
Twenty-one gelled zinc electrodes (negative electrodes) were prepared.

[Preparation of Battery] AA size sealed type having a structure commonly called “inside-out type” (the battery can side is the positive electrode side, and the battery lid side is the negative electrode side) using the above positive electrode and each negative electrode. Alkaline zinc storage batteries (batteries of the present invention) A to U were produced. Here, the inside-out type structure refers to a structure in which a gelled negative electrode is filled in a hollow portion of a cylindrical hollow positive electrode through a cylindrical film separator. In order to control the battery capacity by the positive electrode capacity, the electrochemical theoretical capacity ratio between the positive electrode and the negative electrode is set to 1:
(All of the following batteries had the same capacity ratio.) Further, the total filling amount of nickel oxyhydroxide, zinc alloy, zinc oxide, and rare earth elements and / or rare earth element compounds in the battery can was set to 80% by volume with respect to the internal volume of the battery can. The same filling rate was used).

FIG. 1 is a cross-sectional view of the sealed alkaline zinc storage battery thus produced.
A is a bottomed cylindrical positive electrode can (positive electrode external terminal) 1, a negative electrode lid (negative electrode external terminal) 2, an insulating packing 3, a negative electrode current collector rod 4 made of brass, a cylindrical hollow positive electrode (nickel electrode) 5, It comprises a cylindrical film-shaped separator 6 mainly composed of vinylon, a gelled negative electrode (zinc electrode) 7, and the like.

The positive electrode can 1 accommodates the positive electrode 5 with the outer peripheral surface of the hollow cylindrical body abutting against the inner peripheral surface of the cylindrical portion of the positive electrode can 1. A separator 6 is pressed against the inside, and a gelled negative electrode 7 is provided inside the separator 6.
Is filled. In the center of the circular cross section of the negative electrode 7, a negative electrode current collector rod 4 whose one end is supported by an insulating packing 3 that electrically insulates the positive electrode can 1 from the negative electrode lid 2 is inserted. The opening of the positive electrode can 1 is closed by a negative electrode lid 2. The battery is hermetically sealed by inserting an insulating packing 3 into the opening of the positive electrode can 1, placing the negative electrode cover 2 thereon, and then crimping the open end of the positive electrode can inside.

(Conventional battery X) 3 wt% was added to 49 g of a 40 wt% aqueous potassium hydroxide solution containing 3 wt% of zinc oxide.
After mixing and gelating 1 g of sodium acrylate and a 1% by weight aqueous solution of carboxymethylcellulose, a surfactant (perfluorosulfonic acid) was added to 0.0% with stirring.
5 g was added, and the mixture was aged for 2 hours to ripen to prepare a gel electrolyte. Next, 50 parts by weight of a zinc alloy containing 0.05% by weight of indium and 0.005 parts by weight of sulfanilic acid were mixed with 100 parts by weight of the gel electrolyte to prepare a gelled negative electrode. A conventional battery X was manufactured in the same manner as the methods for manufacturing the batteries A to U of the present invention except that the gelled negative electrode was used.

<Charge / Discharge Cycle Test> Thirty cycles of charge / discharge were performed for each of 10 batteries, after connecting to a 3.9Ω resistor and discharging to 0.9 V, and then charging the battery at 150 mA for 10 hours as one cycle. 1st cycle and 30
The discharge capacity at the cycle was examined. Table 1 shows the results. The discharge capacity in Table 1 is an average of the discharge capacities of 10 batteries, and is an index with the discharge capacity in the first cycle of battery A being 100.

[0022]

[Table 1]

According to Table 1, the batteries A to U of the present invention have a larger discharge capacity in the first cycle than the conventional battery X,
It can be seen that the decrease in the discharge capacity at the 0th cycle is small.

(Experiment 2) In this experiment, the ratio (atomic%) of yttrium to zinc in zinc oxide and zinc alloy was measured.
And the relationship between discharge capacity, charge / discharge cycle characteristics and self-discharge resistance characteristics were examined.

The ratio of yttrium to zinc in the zinc oxide and the zinc alloy (the ratio of yttrium oxide in terms of yttrium element) is changed to 0 atomic% (yttrium oxide: no addition) and 0.01 atomic% instead of 1 atomic%. % (Addition of 0.0113 g of yttrium oxide), 0.05 atomic% (addition of 0.0564 g of yttrium oxide), 0.1 atomic%
(0.113 g of yttrium oxide added), 0.5 atomic% (0.564 g of yttrium oxide added), 5 atomic%
Battery A was prepared in the same manner as the battery A of the present invention, except that the content was changed to 7 atomic% (added 5.64 g of yttrium oxide) or 10 atomic% (added 11.29 g of yttrium oxide). Then, batteries a to h were prepared, and charge and discharge under the same conditions as above were performed for 10 batteries for 3 batteries.
Zero cycles were performed, and discharge capacities at the first cycle and the 30th cycle were examined. Separately prepared batteries must be stored at 45 ° C
Was left in the atmosphere for 14 days, decomposed in water, the generated hydrogen gas was collected, and the amount of hydrogen gas generated by self-discharge (cm ³ ) was determined. Table 2 shows the results. The discharge capacity in Table 2 is an average of the discharge capacities of 10 batteries, and is an index with the discharge capacity in the first cycle of battery A being 100.

[0026]

[Table 2]

According to Table 2, in order to obtain a battery having a large discharge capacity at the first cycle and a small decrease in the discharge capacity at the 30th cycle, the ratio of yttrium to zinc in zinc oxide and the zinc alloy must be set at 0. It can be seen that the content needs to be set to 0.05 to 5 atomic%. With respect to other rare earth element compounds, it was confirmed that the ratio of the rare earth element to zinc in the zinc oxide and the zinc alloy had to be 0.05 to 5 atomic%. In addition, since the amount of hydrogen gas generated in all the batteries is the same, it can be seen that the ratio of yttrium to zinc is independent of the self-discharge resistance.

(Experiment 3) In this experiment, the relationship between the atomic ratio of zinc and indium in the zinc alloy and the discharge capacity, charge / discharge cycle characteristics and self-discharge resistance was examined.

In the preparation of the zinc alloy powder, zinc 100
g, 0 g, 0.012 g, 0.
057 g, 0.12 g, 1.15 g, 1.72 g, 2.
Except that the amount was 30 g, 2.87 g, or 3.44 g, the atomic ratio between zinc and indium was 100: 0, 100: 0.0 in the same manner as in the method for producing the zinc alloy powder in Experiment 1.
1, 100: 0.05, 100: 0.1, 100: 1,
100: 1.5, 100: 2, 100: 2.5 and 10
Nine kinds of zinc alloy powders of 0: 3 were produced. Then, the sealed alkaline zinc storage battery was manufactured in the same manner as the method of manufacturing the battery A of the present invention except that each of these zinc alloy powders was used instead of the zinc alloy powder having an atomic ratio of zinc and indium of 100: 0.5. j to r were prepared.

In the preparation of the zinc alloy powder, 2.09 g of bismuth, 0.40 g of calcium, 0.27 g of aluminum, 1.19 g of tin were used instead of 0.57 g of indium.
g or gallium, except that 0.70 g was used, in the same manner as in the method of preparing the zinc alloy powder in Experiment 1, five kinds of zinc alloy powders having an atomic ratio of zinc and other alloying elements of 100: 1 were prepared. . Then, the atomic ratio of zinc to indium is 10
The sealed alkaline zinc storage batteries u to y were produced in the same manner as the production method of the battery A of the present invention except that each of these zinc alloy powders was used instead of the zinc alloy powder of 0: 0.5.

Further, 100 g of zinc and 1.1 of indium were used.
5 g was heated to 180 ° C. in a nitrogen atmosphere and mixed to prepare a zinc alloy powder having a zinc particle surface coated with indium. Next, a sealed alkaline zinc storage battery z was prepared in the same manner as in the method of producing Battery A of the present invention except that this zinc alloy powder was used instead of the zinc alloy powder having an atomic ratio of zinc and indium of 100: 0.5. Was prepared.

Next, the same charge / discharge cycle test was performed for each battery, and the discharge capacity at the first cycle and the 30th cycle of each battery was determined. After each battery prepared separately was left in an atmosphere of 45 ° C. for 14 days, it was decomposed in water, the generated hydrogen gas was collected, and the amount of hydrogen gas generated by self-discharge (cm ³ ) was determined. Was. Table 3 shows the results. Table 3 also shows the results of the battery A of the present invention and the conventional battery X manufactured in Experiment 1. The discharge capacity in Table 3 is an average of the discharge capacities of 10 batteries for each battery.
It is an index when the discharge capacity at the cycle is 100.

[0033]

[Table 3]

As can be seen from Table 3, in order to obtain a battery having a small self-discharge and a large discharge capacity at the first and 30th cycles, the atomic ratio of zinc to indium in the zinc alloy must be 1
It is understood that the ratio needs to be set to 00: 0.05 to 100: 2.0. For bismuth, calcium, aluminum, tin, and gallium, it was confirmed that the atomic ratio of zinc and their elements needed to be 100: 0.05 to 100: 2.0. Also, the first cycle of the battery z and the third cycle
Since the discharge capacity at the 0th cycle and the amount of generated hydrogen gas are the same as those of the battery n, a zinc alloy powder obtained by coating the surface of zinc particles with indium or the like may be used as the zinc alloy powder. You can see that.

(Experiment 4) In this experiment, the relationship between the ratio (% by weight) of zinc oxide to the zinc alloy and the discharge capacity and charge / discharge cycle characteristics was examined.

The amount of zinc oxide mixed with 100 g of zinc alloy powder was changed to 0 g, 2 g, 5 g, 20 g,
Batteries aa to ah were produced in the same manner as the production method of Battery A of the present invention except that the amount was 30 g, 40 g, 50 g, or 60 g.

The same charge / discharge cycle test as that performed in Experiment 1 was performed on each battery, and the discharge capacity at the first cycle and the 30th cycle of each battery was determined. Table 4 shows the results. The discharge capacity in Table 4 is an index with the discharge capacity in the first cycle of the battery A being 100.

[0038]

[Table 4]

According to Table 4, in order to obtain a battery having a large discharge capacity in the first cycle and a small decrease in the discharge capacity in the 30th cycle, the ratio of zinc oxide to zinc alloy is set to 5 to 40% by weight. It turns out that it is necessary.

[0040]

According to the present invention, there is provided a sealed alkaline zinc storage battery in which self-discharge is small and the battery capacity is not greatly reduced in a short cycle.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an alkaline zinc storage battery (battery of the present invention) manufactured in an example.

[Explanation of symbols]

 BA Alkaline zinc storage battery 1 Positive electrode can 2 Negative electrode lid 3 Insulating packing 4 Negative current collector rod 5 Positive electrode (Nickel electrode) 6 Separator 7 Negative electrode (Zinc electrode)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shin Fujitani 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Koji Nishio 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd.

Claims (2)

[Claims] An atomic ratio of a positive electrode comprising manganese dioxide or nickel oxyhydroxide as a positive electrode active material, zinc, and at least one element selected from the group consisting of indium, bismuth, calcium, aluminum, tin and gallium. 1
A gelled negative electrode obtained by dispersing a zinc alloy of 00: 0.05 to 100: 2.0 in an alkaline electrolyte, wherein the gelled negative electrode is made of zinc oxide. 5 to 40% by weight relative to the alloy, and 0.1 to 0.5 parts by weight of the rare earth element and / or the rare earth compound in the zinc oxide and zinc alloy in the zinc alloy.
0.5 to 5 atomic%, and 75% by volume or more of manganese dioxide or nickel oxyhydroxide, zinc alloy, zinc oxide, a rare earth element and / or a rare earth element compound with respect to the internal volume of the battery can. A sealed alkaline zinc battery. 2. The sealed alkaline zinc storage battery according to claim 1, wherein said rare earth element compound is an oxide, a hydroxide, a carbonate or a fluoride.