JP2000251925A - Sealed alkaline zinc storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase oxygen overvoltage of a positive electrode and enhance high temperature charging characteristics and charging-discharging cycle characteristics by including manganese in a specified amount in γ type nickel oxy hydroxide in the form of a solid solution, and containing a specified amount of lithium ions in an alkaline electrolyte. SOLUTION: γ type nickel oxy hydroxide (γ-NiOOH) in which 5-50 atomic percent manganese is contained in the form of a solid solution based on the total amount of nickel and manganese is used in a positive electrode active material, and an alkaline electrolyte preferably contains 0.05-0.5 wt.% lithium ions. A sealed alkaline zinc storage battery A1 in which a power generating element body occupies 75% of more of a battery can inner volume consists of a cylindrical battery can with bottom (a positive electrode outer terminal) 1; a battery cover (a negative electrode outer terminal) 2; an insulating gasket 3; a cylindrical positive electrode (a nickel electrode); a cylindrical separator film 6 mainly made of vinylon; and a gel-like negative electrode (a zinc electrode).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a positive electrode using gamma-type nickel oxyhydroxide as an active material, a negative electrode using zinc as an active material, an alkaline electrolyte containing potassium hydroxide, a separator, and a negative electrode assembly. The present invention relates to a sealed alkaline zinc storage battery in which a power generating element composed of an electric body occupies 75% or more of the internal volume of a battery can. The present invention relates to an improvement in γ-type nickel oxyhydroxide and an alkaline electrolyte for the purpose of providing. Here, the discharge-started battery refers to a battery that can be discharged for the first time without being charged in advance.

[0002]

2. Description of the Related Art
In sealed alkaline zinc batteries (primary and secondary batteries), generation of hydrogen gas on the negative electrode side during storage (Zn + 4OH)
_{^{- ⇒Zn (OH) 4 2- +}} 2e -; 2H 2 O + 2e - ⇒H
_In order to suppress ₂ + 2OH ⁻ ), an aqueous potassium hydroxide solution in which zinc oxide is dissolved in a saturated amount (saturation amount at room temperature: 6.5% by weight) is used as an alkaline electrolyte.
In particular, by using an aqueous solution of potassium hydroxide having a zinc concentration of 3% by weight or less as an alkaline electrolyte, not only generation of hydrogen gas during storage but also generation of hydrogen gas after discharge can be suppressed. Has recently been reported (see Japanese Patent Application Laid-Open No. 10-40926).

[0003] However, the addition of zinc oxide to an aqueous potassium hydroxide solution improves the characteristics of the negative electrode, but does not improve the characteristics of the positive electrode. Then, the above alkaline electrolyte is used in a secondary battery (sealed alkaline zinc storage battery).
When used at 40 ° C or higher,
There was a problem that the oxygen overvoltage of the positive electrode was reduced, and oxygen gas was generated by electrolysis of water (4OH ⁻ ⇒O ₂ + 2H ₂ O + 4e ⁻ ) on the positive electrode side during charging.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a sealed alkaline zinc storage battery having good high-temperature charge characteristics and charge / discharge cycle characteristics due to a large oxygen overvoltage of the positive electrode. I do.

[0005]

SUMMARY OF THE INVENTION A sealed alkaline zinc storage battery (battery of the present invention) according to the present invention comprises a positive electrode using γ-type nickel oxyhydroxide as an active material, a negative electrode using zinc as an active material, and a hydroxide. A sealed alkaline zinc storage battery in which a power generating element body comprising a potassium-containing alkaline electrolyte, a separator, and a negative electrode current collector occupies 75% or more of the internal volume of the battery can. , Manganese is 5 to 50 based on the total amount of nickel and manganese.
Atomic% solid solution, and the alkaline electrolyte contains 0.05 to 0.5% by weight of lithium ions.

[0006] The alkaline electrolyte of the present invention contains 0.05 to 0.5% by weight of lithium ions. Lithium ions increase the oxygen overvoltage of the positive electrode. Examples of the lithium ion raw material to be added to the alkaline electrolyte include lithium hydroxide and lithium carbonate. The reason why the lithium ion content of the alkaline electrolyte is restricted to 0.05 to 0.5% by weight is that if the content is less than 0.05% by weight, the oxygen overvoltage of the positive electrode cannot be sufficiently increased. A sealed alkaline zinc storage battery having good high-temperature charging characteristics cannot be obtained. On the other hand, when the lithium ion content of the alkaline electrolyte exceeds 0.5% by weight, the ionic conductivity of the alkaline electrolyte decreases. This is because the discharge capacity decreases.

It is preferable to add sodium hydroxide to the alkaline electrolyte. Sodium hydroxide increases the oxygen overpotential of the positive electrode. However, when the alkaline electrolyte contains more than 5% by weight of sodium hydroxide, the ionic conductivity of the alkaline electrolyte decreases, and the battery capacity decreases.
Further, zinc oxide may be added to the alkaline electrolyte.
Zinc oxide generates hydrogen gas at the negative electrode (self-discharge)
To suppress the rise in the internal pressure of the battery or the leakage of the alkaline electrolyte. The preferred zinc oxide content of the alkaline electrolyte is from 2.0 to 6.5% by weight.

The alkaline electrolyte preferably has a potassium hydroxide concentration of 35 to 45% by weight. When the concentration of potassium hydroxide is less than 35% by weight, zinc is passivated at the time of discharge and the discharge capacity decreases. On the other hand, when the concentration of potassium hydroxide exceeds 45% by weight, the solubility of zinc increases and dendrites are formed. Easy to generate.

The positive electrode active material of the present invention is γ-type nickel oxyhydroxide (γ-NiOOH) in which manganese forms a solid solution of 5 to 50 atomic% based on the total amount of nickel and manganese. The solid solution of manganese increases the oxygen overvoltage of the positive electrode. The reason why the manganese solid solution rate is regulated to 5 to 50 atomic% is that when the manganese solid solution rate is less than 5 atomic%, the oxygen overvoltage of the positive electrode cannot be sufficiently increased, so that the high-temperature charging characteristics are good. When the sealed alkaline zinc storage battery cannot be obtained, but the manganese solid solution rate exceeds 50 atomic%, the filling amount of the γ-type nickel oxyhydroxide, which is the positive electrode active material, decreases, and the battery capacity decreases. It is because it decreases. The γ-type nickel oxyhydroxide in which manganese is dissolved can be obtained by oxidizing nickel hydroxide in which manganese is dissolved with an oxidizing agent such as sodium hypochlorite. Nickel hydroxide in which manganese is dissolved is prepared by adding an alkali to an aqueous solution containing a manganese salt and a nickel salt to adjust the pH to 9 to 12, and then mixing for a predetermined time (alkali coprecipitation method). can do.

As the positive electrode active material of the present invention, γ-type nickel oxyhydroxide in which at least one element selected from the group consisting of zinc, cobalt, bismuth, aluminum and a rare earth element is used as a solid solution in addition to manganese is used. May be.
By further dissolving these elements, the oxygen overvoltage of the positive electrode can be further increased.

[0011]

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 may be appropriately modified within the scope of the gist of the present invention. Is possible.

(Experiment 1) A battery of the present invention and a comparative battery were manufactured, and the battery characteristics of each battery were examined.

(Example 1) [Preparation of alkaline electrolyte] 441 g of potassium hydroxide (purity: 85% by weight), 25 g of sodium hydroxide, 12 g of lithium hydroxide monohydrate and 30 g of zinc oxide were mixed with water. 4
Dissolved in 92 g of potassium hydroxide, 37.5% by weight,
An alkaline electrolyte containing 2.5% by weight of sodium hydroxide, 3% by weight of zinc oxide, and 0.2% by weight of lithium ion was prepared.

[Preparation of Negative Electrode] Zinc alloy powder (particle size: 20 to 200 mesh) composed of 99.85% by weight of zinc, 0.10% by weight of indium and 0.05% by weight of bismuth 6
5 g, zinc oxide 13 g, and polyacrylic acid as a thickener (manufactured by Nippon Pure Chemical Co., Ltd., product code "Junron PW15
0 ") 1 g and the above-mentioned alkaline electrolyte solution 34 g were mixed to prepare a negative electrode containing gelled zinc as an active material.

[Preparation of Positive Electrode] 100 ml of a 0.1 mol / l aqueous solution of nickel sulfate and 2.6 ml of manganese sulfate were used.
100 ml of a 7 × 10 ⁻² mol / l aqueous solution and 100 ml of a 5% by weight aqueous ammonia solution are simultaneously poured into water in a water tank, and a 20% by weight aqueous sodium hydroxide solution is dropped with stirring, and the pH of the solution is measured with a pH meter. Was adjusted to 11 ± 0.3, the liquid in the water tank was maintained at 35 ° C., and mixed for 1 hour. The precipitate formed in the water tank was filtered off, washed with water, and then at room temperature (about 25 ° C.). Vacuum drying was performed to obtain nickel hydroxide in which manganese was dissolved. The manganese solid solubility was determined by atomic absorption spectroscopy to be 20 atomic%.

Then, 500 ml of a 10 mol / l aqueous solution of sodium hydroxide and 10% by weight as an oxidizing agent
1600 ml of an aqueous solution of sodium hypochlorite was stirred and mixed, heated and maintained at 60 ° C. to prepare an oxidized solution,
100 g of the above-mentioned nickel hydroxide in which manganese was solid-dissolved was added to this oxidation treatment liquid, and the mixture was stirred and mixed for 1 hour, filtered, washed with water, and dried at 60 ° C. A solid solution γ-type nickel oxyhydroxide was obtained.
The manganese solid solution rate of this γ-type nickel oxyhydroxide was determined by atomic absorption spectroscopy. As a result, it was 20 atom%, as in the case of manganese solid solution nickel hydroxide before oxidation treatment.

Next, 90 g of the above-mentioned γ-type nickel oxyhydroxide in which manganese was dissolved, 5 g of graphite powder, and 5 g of a 30% by weight aqueous solution of potassium hydroxide were mixed with a grinder to obtain 3 g.
The mixture was mixed for 0 minutes and molded under pressure to produce a cylindrical molded body having an outer diameter of 13.3 mm, an inner diameter of 9 mm, and a height of 13.7 mm. In the production of the battery, three cylindrical molded bodies were joined in series and used as one positive electrode.

[Production of Sealed Alkaline Zinc Storage Battery] Using the above positive electrode and negative electrode, a so-called “inside-out type” is used.
AA-size sealed alkaline zinc storage battery A1 (battery of the present invention) having a structure called “AA size” was produced. Here, the inside-out type battery refers to a battery having a structure in which a negative electrode is disposed inside a cylindrical positive electrode via a separator, and in this type of battery, a battery can has a positive electrode side, and a battery lid has a negative electrode. Be on the side. 1.64 g of the above alkaline electrolyte was injected into the separator. The weight of the positive electrode was 5.8 g so that the battery capacity was regulated by the positive electrode capacity.
(Theoretical capacity: 1500 mAh), and the weight of the negative electrode was 5.6 g.
(Theoretical capacity: 3000 mAh), the capacity ratio between the positive electrode and the negative electrode was set to 1: 2. In addition, the volume inside the battery can of the power generating element body including the positive electrode, the negative electrode, the alkaline electrolyte, the separator, and the negative electrode current collector rod (the volume of the inner part of the insulating packing)
Was set to 80% by volume. In all of the following batteries, the capacity ratio between the positive electrode and the negative electrode was set to 1: 2, and the volume ratio of the power generating element to the internal volume of the battery can was set to 80%.

FIG. 1 is a cross-sectional view schematically showing a sealed alkaline zinc storage battery thus produced. The illustrated sealed alkaline zinc storage battery A1 has a cylindrical battery can (a positive electrode external terminal) 1 with a bottom, and a battery cover. (Negative electrode external terminal) 2, insulating packing 3, negative electrode current collector rod 4 made of brass, cylindrical positive electrode (nickel electrode) 5, cylindrical separator film 6 mainly composed of vinylon, gel negative electrode (zinc electrode) 7 etc.

The positive electrode 5 is housed in the battery can 1 with the outer peripheral surface of the cylinder abutting on the inner peripheral surface of the battery can 1, and the outer peripheral surface is brought into contact with the inner peripheral surface of the positive electrode 5. A cylindrical separator film 6 is pressed against the inside, and the inside of the separator film 6 is filled with a gelled negative electrode 7. At 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 battery can 1 from the battery lid 2 is inserted. The opening of the battery can 1 is closed by a battery cover 2. The battery is hermetically sealed by fitting an insulating packing 3 into the opening of the battery can 1, placing the battery lid 2 thereon, and caulking the opening end of the battery can inward.

(Example 2) Except for using a 5.63 × 10 ⁻³ mol / L aqueous solution of manganese sulfate instead of the 2.67 × 10 ⁻² mol / L aqueous solution of manganese sulfate in the preparation of the positive electrode. In the same manner as in Example 1, a sealed alkaline zinc storage battery A2 (battery of the present invention) was produced. The manganese solid solution ratio of γ-type nickel oxyhydroxide used as the positive electrode active material was 5 atomic%.

(Example 3) Except for using a 1.19 × 10 ^-2 mol / L aqueous solution of manganese sulfate instead of the 2.67 × 10 ^-2 mol / L aqueous solution of manganese sulfate in producing the positive electrode. In the same manner as in Example 1, a sealed alkaline zinc storage battery A3 (battery of the present invention) was produced. The manganese solid solution rate of γ-type nickel oxyhydroxide used as the positive electrode active material was 10 atomic%.

(Example 4) Except for using a 4.58 × 10 ^-2 mol / L aqueous solution of manganese sulfate instead of the 2.67 × 10 ^-2 mol / L aqueous solution of manganese sulfate in the preparation of the positive electrode In the same manner as in Example 1, a sealed alkaline zinc storage battery A4 (battery of the present invention) was produced. The manganese solid solution rate of γ-type nickel oxyhydroxide used as the positive electrode active material was 30 atomic%.

(Example 5) Except for using a 7.13 × 10 ^-2 mol / L aqueous solution of manganese sulfate instead of the 2.67 × 10 ^-2 mol / L aqueous solution of manganese sulfate in producing the positive electrode In the same manner as in Example 1, a sealed alkaline zinc storage battery A5 (battery of the present invention) was produced. The manganese solid solution rate of the γ-type nickel oxyhydroxide used as the positive electrode active material was 40 atomic%.

Example 6 A positive electrode was prepared in the same manner as in Example 1 except that an aqueous solution of manganese sulfate of 0.11 mol / liter was used instead of the aqueous solution of manganese sulfate of 2.67 × 10 ^-2 mol / liter. In the same manner as in the above, a sealed alkaline zinc storage battery A6 (battery of the present invention) was produced. The manganese solid solution ratio of the γ-type nickel oxyhydroxide used as the positive electrode active material was 50 atomic%.

Comparative Example 1 Except for using a 3.31 × 10 ⁻³ mol / L aqueous solution of manganese sulfate instead of the 2.67 × 10 ⁻² mol / L aqueous solution of manganese sulfate in producing a positive electrode. In the same manner as in Example 1, a sealed alkaline zinc storage battery X1 (comparative battery) was produced. The manganese solid solution rate of γ-type nickel oxyhydroxide used as the positive electrode active material was 3 atomic%.

Comparative Example 2 The procedure of Example 1 was repeated, except that a 0.13 mol / L aqueous solution of manganese sulfate was used in place of the 2.67 × 10 ^-2 mol / L aqueous solution of manganese sulfate. In the same manner as in the above, a sealed alkaline zinc storage battery X2 (comparative battery) was produced. The manganese solid solution ratio of the γ-type nickel oxyhydroxide used as the positive electrode active material was 55 atomic%.

Comparative Example 3 A sealed alkaline zinc storage battery was produced in the same manner as in Example 1, except that an aqueous solution in which 3% by weight of zinc oxide and 40% by weight of potassium hydroxide were dissolved in water was used as the alkaline electrolyte. X3 (comparative battery) was produced.

Batteries A1 to A6 of the present invention and Comparative Batteries X1 to X1
For X3, Table 1 shows the concentration of the aqueous manganese sulfate solution used for producing the positive electrode active material, and the manganese solid solubility of γ-type nickel oxyhydroxide used as the positive electrode active material.

[0030]

[Table 1]

[Storage Characteristics of Each Battery] After each battery was stored at 45 ° C. for 30 days, it was decomposed in water, the hydrogen gas generated in the battery was collected, and the amount of hydrogen gas generated during storage ( cm
³ ) Asked. Table 2 shows the results. A battery with a smaller amount of generated hydrogen gas has better storage characteristics.

[The discharge capacity of the first cycle of each battery, 10
Capacity maintenance rate at cycle and number of leaked batteries at cycle 10] 100 mA at 25 ° C. for 10 batteries
After charging to 1 V at 100 mA, charging and discharging at 100 mA to 1.95 V were performed for 10 cycles, and the discharge capacity at the first cycle, the capacity retention rate at the tenth cycle, and the number of leaked batteries at the tenth cycle were examined. Table 2 shows the results. 1 in Table 2
The discharge capacity at the cycle is an index with the discharge capacity of the battery A1 of the present invention being 100. Further, the capacity retention rate at the 10th cycle is 1% of the discharge capacity at the 1st cycle of each battery.
It is the ratio (%) of the discharge capacity at the 0th cycle, and is the average value of the capacity retention rates of the batteries from which the electrolyte did not leak. Further, the numerator of the fraction shown in the column of the number of leaked batteries in Table 2 indicates the number of leaked batteries. The number in parentheses below the battery code in Table 2 indicates the manganese solid solution rate (atomic%).

[High Temperature Charging Characteristics of Each Battery] Each of the above-mentioned batteries (each 10 batteries) having been subjected to 10 charge / discharge cycles was subjected to 45
After charging to 1.95 V at 100 mA at ° C, 25
The battery was discharged at 100 ° C. to 1.0 V at 100 ° C., and the ratio P (%) of the discharge capacity C11 at the eleventh cycle to the discharge capacity C10 at the tenth cycle [(C10 / C11) × 10
0], and the high-temperature charging characteristics of each battery were examined. Table 2 shows the results. The higher the ratio P, the better the high-temperature charging characteristics.

[0034]

[Table 2]

As shown in Table 2, the batteries A1 to A6 of the present invention using γ-type nickel oxyhydroxide having a manganese solid solution rate of 5 to 50 atomic% as the positive electrode active material were subjected to the first and tenth cycles. The discharge capacity was large, and the number of leaked batteries at the 10th cycle was 0 (zero). On the contrary,
In the comparative battery X1 using γ-type nickel oxyhydroxide having a manganese solid solution rate of 3 atomic% as the positive electrode active material, oxygen gas was generated during charging because the oxygen overvoltage of the positive electrode was not sufficiently large. In one of the 10 batteries, liquid leakage occurred. Comparative battery X2 using γ-type nickel oxyhydroxide having a manganese solid solution rate of 55 atomic% as the positive electrode active material had a reduced battery capacity due to a decrease in the filling amount of γ-type nickel oxyhydroxide. From these results,
It is understood that it is necessary to use γ-type nickel oxyhydroxide having a manganese solid solution rate of 5 to 50 atomic%. Comparative battery X3 using an aqueous potassium hydroxide solution to which neither sodium hydroxide nor lithium hydroxide was added as an alkaline electrolyte.
Indicates that oxygen gas is generated at the time of charging because the oxygen overvoltage of the positive electrode is small, and two out of ten batteries in the tenth cycle
Liquid leakage occurred in the individual. The comparative battery Y has a ratio P
Is as small as 80%, the high-temperature charging characteristics were not good.

(Experiment 2) The relationship between the lithium ion concentration of the alkaline electrolyte and the battery characteristics was examined.

In preparing the alkaline electrolyte, the amount of lithium hydroxide monohydrate was adjusted to 1.8 g and 3.0 g, respectively.
g, 6.0 g, 30.2 g and 42.3 g, in the same manner as in the preparation method of the alkaline electrolyte in Example 1, the lithium ion concentration of the alkaline electrolyte was 0.03% by weight, 0.05% by weight, 0.1% by weight,
Five types of alkaline electrolytes were prepared at 0.5% by weight and 0.7% by weight. Next, when the lithium ion concentration is 0.2
Ten sealed alkaline zinc storage batteries B1 to B5 were prepared in the same manner as in Example 1 except that the above-mentioned respective alkaline electrolytes were used instead of the alkali electrolyte of weight%. Do the same charge and discharge cycle test as
Capacity retention rate (%) at the 10th cycle of each battery, number of leaked batteries at the 10th cycle, discharge capacity C10 at the 10th cycle
Ratio P of the discharge capacity C11 at the 11th cycle with respect to
(%) And the amount of generated hydrogen gas (cm ³ ) during storage. Table 4 shows the results. Table 4 also shows the results of the battery A1 of the present invention. The number in parentheses in the column of the capacity retention ratio at the 10th cycle is the ratio of the discharge capacity at the 10th cycle of each battery to the discharge capacity at the 1st cycle of the battery A1 of the present invention.

[0038]

[Table 3]

[0039]

[Table 4]

As shown in Table 4, it can be seen that the batteries A1 and B2 to B4 using the alkaline electrolyte having a lithium ion concentration of 0.05 to 0.5% by weight have good leakage resistance and high-temperature charging characteristics. On the other hand, in the battery B1 in which the lithium ion concentration of the alkaline electrolyte was as low as 0.03% by weight, the oxygen overvoltage of the positive electrode could not be sufficiently increased, so that oxygen gas was generated at the time of charging, and 10 cycles. Liquid leakage occurred in one of the ten batteries in the eye. The battery B1 did not have good high-temperature charging characteristics, as can be seen from the fact that the ratio P was as small as 82%. In the battery B5 in which the lithium ion concentration of the alkaline electrolyte was as high as 0.7% by weight, the lithium ion concentration was too high and the ionic conductivity was lowered, so that the battery capacity was reduced. These results show that it is necessary to use an alkaline electrolyte having a lithium ion concentration of 0.05 to 0.5% by weight.

(Experiment 3) The relationship between the potassium hydroxide concentration of the alkaline electrolyte and the battery characteristics was examined.

In the preparation of the alkaline electrolyte, the same procedure as in Example 1 was repeated except that potassium hydroxide, lithium hydroxide, zinc oxide and water were used as shown in Table 5, respectively. Were manufactured, and the same charge / discharge cycle test as that performed in Experiment 1 was performed, and the capacity maintenance ratio (%) of each battery at the 10th cycle, the number of leaked batteries at the 10th cycle, and the number of batteries at the 10th cycle Ratio P (%) of discharge capacity C11 at the 11th cycle to discharge capacity C10
The amount of hydrogen gas generated during storage (cm ³ ) was examined. Table 6 shows the results. Table 6 also shows the results of the battery A1 of the present invention. The capacity retention ratio in Table 6 is a ratio of the discharge capacity at the tenth cycle to the discharge capacity at the first cycle of each battery.

[0043]

[Table 5]

[0044]

[Table 6]

As shown in Table 6, it is understood that the batteries A1 and C2 to C6 having a potassium hydroxide concentration of 35 to 45% by weight have good charge / discharge cycle characteristics, and excellent liquid leakage resistance and high-temperature charge characteristics. . On the other hand, in the battery C1, the capacity maintenance ratio at the tenth cycle is low because zinc of the negative electrode was passivated. Battery C7 has a low capacity retention ratio at the tenth cycle due to dendrite short-circuiting of the negative electrode zinc. From these results, potassium hydroxide concentration of 35
It can be seen that it is preferable to use an alkaline electrolyte of up to 45% by weight.

(Experiment 4) The relationship between the concentration of sodium hydroxide and the battery characteristics when sodium hydroxide was added to the alkaline electrolyte was examined.

In the preparation of the alkaline electrolyte, the sealed alkaline zinc was prepared in the same manner as in Example 1 except that potassium hydroxide, sodium hydroxide, lithium hydroxide, zinc oxide and water were used in the amounts shown in Table 7. Ten storage batteries D1 to D4 were manufactured, and the same charge / discharge cycle test as that performed in Experiment 1 was performed. The capacity maintenance ratio (%) of each battery at the tenth cycle, the number of leaked batteries at the tenth cycle, Discharge capacity C at eleventh cycle with respect to discharge capacity C10 at tenth cycle
11 and the amount of hydrogen gas generated during storage (c)
m ³ ) was determined. Table 8 shows the results. Table 8 also shows the results of the battery A1 of the present invention. The capacity retention rate in Table 8 is
This is the ratio of the discharge capacity at the tenth cycle to the discharge capacity at the first cycle of each battery.

[0048]

[Table 7]

[0049]

[Table 8]

As shown in Table 8, batteries A1 and D2 to D4 containing sodium hydroxide in the alkaline electrolyte were used.
It can be seen that the ratio P was large and the high-temperature charging characteristics were good because the oxygen overvoltage of the positive electrode was increased compared to the battery D1 in which sodium hydroxide was not contained in the alkaline electrolyte. However, a battery D4 having a sodium hydroxide concentration of 7% by weight was used.
Has a very low capacity retention ratio at the tenth cycle because the ionic conductivity of the alkaline electrolyte is not as good as that of batteries A1, D2, and D3 having a sodium hydroxide concentration of 5% by weight or less. These results indicate that the concentration of sodium hydroxide when adding sodium hydroxide to the alkaline electrolyte is preferably 5% by weight or less.

(Experiment 5) The relationship between the zinc oxide concentration and the battery characteristics when zinc oxide was added to the alkaline electrolyte was examined.

In the preparation of the alkaline electrolyte, a sealed alkaline zinc oxide was prepared in the same manner as in Example 1 except that potassium hydroxide, sodium hydroxide, lithium hydroxide, zinc oxide and water were used in the amounts shown in Table 9. Ten storage batteries E1 to E4 were manufactured, and the same charge / discharge cycle test as that of Experiment 1 was performed. The capacity maintenance ratio (%) of each battery at the tenth cycle, the number of leaked batteries at the tenth cycle, and ten cycles Discharge capacity C at 11th cycle with respect to discharge capacity C10 at eye
11 and the amount of hydrogen gas generated during storage (c)
m ³ ) was determined. Table 10 shows the results. Table 10 also shows the results of the battery A1 of the present invention. The capacity retention ratio in Table 10 is a ratio of the discharge capacity at the tenth cycle to the discharge capacity at the first cycle of each battery.

[0053]

[Table 9]

[0054]

[Table 10]

Table 10 shows that the batteries E2, A, E3, and E4 in which the concentration of zinc oxide in the alkaline electrolyte was 2 to 6.5% by weight were excellent in various characteristics. The reason why the number of leaked batteries in the battery E1 is large is that a large amount of hydrogen gas is generated in the negative electrode because the amount of zinc oxide added is small.

[0056]

According to the present invention, there is provided a sealed alkaline zinc storage battery having excellent high-temperature charge characteristics, liquid leakage resistance and charge / discharge cycle characteristics.

[Brief description of the drawings]

FIG. 1 is a sectional view of a sealed alkaline zinc storage battery manufactured in an example.

[Description of Signs] A1 sealed alkaline zinc storage battery 1 battery can 2 battery lid 3 insulating packing 4 negative electrode current collector rod 5 positive electrode (nickel electrode) 6 separator film 7 negative electrode (zinc electrode)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mamoru Kimoto 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Yasuhiko Ito 2-chome Keihanhondori, Moriguchi-shi, Osaka 5-5 Sanyo Electric Co., Ltd. (72) Inventor Koji Nishio 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. 5H003 AA04 BB04 BB14 BD00 BD04 5H016 EE01 EE05 HH00 HH01 5H028 AA06 AA07 EE01 EE05 FF03 FF04 HH00 HH01 HH02

Claims (5)

[Claims] 1. A power generation system comprising: a positive electrode using gamma-type nickel oxyhydroxide as an active material; a negative electrode using zinc as an active material; an alkaline electrolyte containing potassium hydroxide; a separator; and a negative electrode current collector. In a sealed alkaline zinc storage battery in which the element body occupies 75% or more of the internal volume of the battery can, 5 to 50 atomic% of manganese forms a solid solution with the γ-type nickel oxyhydroxide based on the total amount of nickel and manganese. And the alkaline electrolyte has a lithium ion content of 0.05%.
A sealed alkaline zinc storage battery characterized by containing 0.5% by weight. 2. The sealed alkaline zinc storage battery according to claim 1, wherein said alkaline electrolyte contains sodium hydroxide in an amount not exceeding 5% by weight. 3. The method according to claim 2, wherein the alkaline electrolyte contains zinc oxide of 2.0%.
The sealed alkaline zinc storage battery according to claim 1, wherein the content of the alkaline zinc storage battery is in the range of about 6.5% by weight. 4. The sealed alkaline zinc storage battery according to claim 1, wherein the alkaline electrolyte has a potassium hydroxide concentration of 35 to 45% by weight. 5. The method according to claim 1, wherein at least one element selected from the group consisting of zinc, cobalt, bismuth, aluminum and rare earth elements is further dissolved in said γ-type nickel oxyhydroxide. Sealed alkaline zinc storage battery.