JP2011216218A - Alkaline dry battery - Google Patents

Abstract

An object of the present invention is to provide an alkaline battery capable of preventing the battery from leaking by suppressing an increase in battery internal pressure even when an unused alkaline battery is accidentally charged by a charger.
In an alkaline battery, a negative electrode includes zinc alloy powder and a gel alkaline electrolyte. The gel-like alkaline electrolyte contains 0.00002 M parts by weight (where M is the molecular weight of the quaternary ammonium salt) of quaternary ammonium salt with respect to 100 parts by weight of zinc alloy powder. The alkaline electrolyte and the alkaline electrolyte in the gel alkaline electrolyte each contain 0.3 mol / l or more of a zinc compound.
[Selection] Figure 2

Description

  The present invention relates to an alkaline dry battery (hereinafter sometimes referred to as “battery”), and more particularly, to an alkaline dry battery having improved leakage resistance when charged accidentally.

  Alkaline batteries using manganese dioxide for the positive electrode, zinc for the negative electrode, and an alkaline aqueous solution for the electrolyte are widely used because they are versatile and inexpensive. Zinc used for the negative electrode active material of an alkaline battery has characteristics such as a large theoretical discharge capacity per mass of 820 mAh / g, low toxicity, low environmental load, and low cost. As the negative electrode active material of the alkaline dry battery, it is desirable to use amorphous zinc powder obtained by a gas atomizing method or the like.

  When the zinc powder is corroded in the alkaline electrolyte, hydrogen gas is generated and the internal pressure of the battery increases. When the internal pressure of the battery rises to the operating pressure of the safety valve, the safety valve opens and gas is released out of the battery. At this time, not only the gas but also the alkaline electrolyte is released from the opened safety valve, and as a result, the battery may leak.

  On the other hand, in the old days, an anticorrosion method for increasing the hydrogen generation overvoltage of zinc by adding mercury to the negative electrode to amalgamate the surface of the zinc powder has been performed. However, the social needs for low pollution increased, and from about 1980 to 1990, the mercury-free alkaline batteries were advanced. For example, the following techniques have been proposed as anticorrosion techniques that replace mercury addition.

  In order to suppress the generation of hydrogen gas during storage, a method of adding a cationic organic substance to a negative electrode or an alkaline electrolyte has been proposed (see Patent Document 1). According to this proposal, since generation of hydrogen gas on the negative electrode surface can be suppressed, the leakage resistance of the alkaline dry battery can be improved.

  In addition, for the purpose of improving storage stability during high-temperature storage, a method has been proposed in which the concentration of potassium hydroxide in the alkaline electrolyte is a certain level (see Patent Document 2).

  Furthermore, a method for defining the amount of zinc oxide in the battery has been proposed for the purpose of preventing leakage when one of the four AA alkaline batteries is loaded in the opposite direction (Patent Document 3). reference). According to this proposal, a predetermined amount of zinc oxide is mixed in the battery in advance to cause a reduction reaction of zinc oxide prior to the hydrogen gas generation reaction in the negative electrode in the initial stage of reverse loading, thereby generating hydrogen gas generation. It can be avoided.

Japanese Patent Publication No. 6-65040 JP 2007-115701 A JP 2006-156158 A

  Conventionally, when a plurality of alkaline batteries are used in series, one of the alkaline batteries is erroneously loaded in the opposite direction, and as a result, the alkaline battery may be charged. Furthermore, in recent years, with the rapid spread of AA-size or AAA-type nickel metal hydride secondary batteries, alkaline batteries are erroneously loaded into these chargers, and as a result, the batteries are charged. The cases leading to are becoming apparent.

  In an alkaline battery, even during normal storage, some hydrogen gas is generated due to the corrosion of zinc powder by the alkaline electrolyte as described above. However, under conditions where the alkaline battery is over-appropriated, such as when the alkaline battery is reversely connected or when the alkaline battery is charged by a charger, the amount of hydrogen gas generated becomes extremely large and the alkaline battery leaks. The possibility of reaching a liquid increases. In order to suppress this leakage, it is desirable to suppress an increase in battery internal pressure by reducing the amount of hydrogen gas generated by the charging reaction.

  In Patent Documents 1 and 2 shown above, the effect of suppressing the generation of hydrogen gas during storage or storage at a high temperature is recognized, but it is difficult to sufficiently suppress the generation of hydrogen gas during charging.

  The technology described in Patent Document 3 relates to the prevention of leakage when an alkaline battery is accidentally charged in the opposite direction. Therefore, in this technology, the effect of preventing leakage at the time of reverse loading into a light load device is achieved. Is allowed. However, with this technology, it is not possible to obtain the effect of preventing leakage caused by charging with a relatively large load such as charging of an alkaline battery by a charger (hereinafter, this charging is referred to as “high load charging”). difficult. Therefore, even if this technique is used, it is difficult to suppress rapid generation of hydrogen gas during high-load charging.

  As described above, in these conventional techniques, it is difficult to suppress the intense generation of gas during high-load charging, and there is room for improvement in measures against liquid leakage when an alkaline dry battery is accidentally charged with a charger.

  In order to solve the above problems, in the alkaline dry battery according to the present invention, the alkaline electrolyte is held at least in the separator. The negative electrode contains zinc alloy powder and a gel alkaline electrolyte. The gel alkaline electrolyte contains a quaternary ammonium salt in an amount of 0.00002 M parts by weight (where M is the molecular weight of the quaternary ammonium salt, the same applies hereinafter) with respect to 100 parts by weight of the zinc alloy powder. . The alkaline electrolyte and the alkaline electrolyte in the gel alkaline electrolyte contain 0.3 mol / l or more of a zinc compound.

  Even when the alkaline dry battery according to the present invention is charged with a high load, the time for generating hydrogen gas from the negative electrode can be shortened, and the amount of generated gas can be minimized. . Thereby, since the raise of the internal pressure of a battery can be suppressed, it can prevent that a battery reaches liquid leakage.

  When the alkaline battery according to the present invention is an AA alkaline battery, the alkaline battery according to the present invention can be defined as follows. When constant current charging is performed at 250 mA in a 20 ± 2 ° C. environment, T2−T1 ≦ 10 (min). Here, T1 is the time (minutes) required from the start of charging until the battery voltage rises and reaches 2.2V. T2 is the time (minutes) required from the start of charging until the battery voltage drops to 2.1 V after passing through the hydrogen gas generation stage.

  In the case where the alkaline dry battery according to the present invention is an AAA alkaline battery, the alkaline dry battery according to the present invention can be defined as follows. When constant current charging is performed at 100 mA in a 20 ± 2 ° C. environment, T2−T1 ≦ 10 (min). T1 and T2 are as described above.

  In the present invention, even when the alkaline dry battery is charged with a high load, the amount of gas generated in the battery can be suppressed, so that leakage due to an increase in the battery internal pressure can be suppressed.

(A) to (c) are battery voltage behavior, behavior of gas generation, behavior of negative electrode potential, behavior of positive electrode potential when an unused alkaline dry battery is charged at a charging rate of 250 mA in an environment of 20 ± 2 ° C. It is a graph which shows a behavior. It is a half sectional view of an alkaline battery concerning one embodiment of the present invention. 2 is a table summarizing the results of Example 1. 10 is a table summarizing the results of Example 2. 10 is a table summarizing the results of Example 3. It is the table | surface which put together the result of Example 4. FIG. 10 is a table summarizing the results of Example 5. 10 is a table summarizing the results of Example 6.

  Before describing the embodiments of the present invention, the background to the completion of the present invention will be described.

  In order to devise appropriate measures to prevent leakage due to high load charging, the inventors of the present application investigated the voltage behavior of unused alkaline batteries during high load charging, and the mechanism of gas generation (mechanism) ) Was considered.

  When the unused alkaline battery was charged, the results shown in FIGS. 1A to 1C were obtained. FIG. 1A shows the behavior of the battery voltage (L11 in the figure) and the behavior of the gas generation amount (L12 in the figure), and FIG. 1B shows the behavior of the negative electrode potential. FIG. 1 (c) shows the behavior of the positive electrode potential. Here, each behavior of the negative electrode potential and the positive electrode potential is determined by opening a hole in a part of the positive electrode case (battery case) of the battery and establishing a liquid junction with the mercury / mercury oxide reference electrode outside the battery via the salt bridge. The measured vertical axis represents the potential with respect to the mercury / mercury oxide electrode on each vertical axis of FIG. 1 (b) and FIG. 1 (c).

  As shown in FIGS. 1A to 1C, the potential behavior of the positive electrode and the negative electrode of the battery during high load charging can be classified into three regions I to III. In region I, the negative electrode potential gradually decreases and the positive electrode potential gradually increases. Thereafter, the negative electrode potential drops rapidly and shifts to region II. In region II, the negative electrode potential is stable, and the positive electrode potential rises gently as in region I. Then, the increase in the positive electrode potential stops and the region III is transferred. In region III, the negative electrode potential rises to the same potential as in region I and then stabilizes. On the other hand, the positive electrode potential gradually falls.

  Regarding the behavior of the gas generation amount, in the region I, the generation of gas is not confirmed. When moving to region II, the generation of gas is confirmed, and the amount thereof increases with time. Thereafter, when moving to region III, the increase in the amount of gas generation becomes very gradual, and is finally hardly confirmed.

  Based on the behavior of the negative electrode potential, the positive electrode potential, and the amount of gas generated as described above, the reactions at the negative electrode and the positive electrode in each region were considered as follows.

  In region I, it is considered that the oxidation reaction of manganese dioxide represented by the formula (1) occurs at the positive electrode, and the reduction reaction of the zinc complex ion represented by the formula (2) occurs at the negative electrode.

Positive electrode: MnO _2-x + 2xOH ⁻ → MnO ₂ + xH ₂ O + 2xe ⁻ (1)
Negative electrode: Zn (OH) ₄ ²⁻ + 2e ⁻ → Zn + 4OH ⁻ (2)
When the zinc complex ion (Zn (OH) ₄ ²⁻ ) present in the electrolyte (generic name for alkaline electrolyte and gel alkaline electrolyte, the same applies hereinafter) is completely consumed, the negative electrode potential drops sharply. The hydrogen generation potential is reached. Then, the reaction shown in the formula (3) starts and enters the region II.

  In the region II, it is considered that the oxidation reaction of manganese dioxide continues in the positive electrode from the region I, and in the negative electrode, the hydrogen gas generation reaction (hereinafter simply referred to as “hydrogen gas generation reaction”) represented by the formula (3). ) Seems to have happened. As described above, since hydrogen gas is generated in the negative electrode, the amount of gas generated increases with the passage of time, and thus the internal pressure of the battery increases.

Positive electrode: MnO _2-x + 2xOH ⁻ → MnO ₂ + xH ₂ O + 2xe ⁻ (1)
Negative electrode: 2H ₂ O + 2e ⁻ → H ₂ ↑ + 2OH ⁻ (3)
The oxidation of manganese dioxide at the positive electrode is almost completed, and the positive electrode potential reaches the oxygen generation potential. Then, at the positive electrode, the reaction shown in the formula (4) starts and enters the region III.

  In region III, an oxygen gas generation reaction represented by the formula (4) occurs at the positive electrode. By the way, in the region III, the amount of gas generated has hardly increased. From this, in the negative electrode, it is considered that the oxygen gas consumption reaction (hereinafter simply referred to as “oxygen gas consumption reaction”) represented by the formula (5) takes precedence over the hydrogen gas generation reaction. That is, in region III, the hydrogen gas generation reaction at the negative electrode is suppressed, and the oxygen generated at the positive electrode is reduced and consumed at the negative electrode, so that an increase in the amount of gas generation is suppressed.

Positive electrode: 4OH ⁻ → O ₂ + 2H ₂ O + 4e ⁻ (4)
Negative electrode: 2H ₂ O + O ₂ + 4e ⁻ → 4OH ⁻ (5)
Based on the above considerations, the inventors of the present application will change from the hydrogen gas generation reaction to the oxygen gas consumption reaction at the negative electrode when the amount of hydrogen gas generation in the region II decreases or when the region II shifts to the region III. It was considered that if the transition was made promptly, the increase in the internal pressure of the battery at the time of high load charge could be prevented, and thus the liquid leakage at the time of high load charge could be prevented.

  The inventors of the present application believe that it is desirable to realize both the reduction in the amount of hydrogen gas generated in region II and the rapid transition to the oxygen gas consumption reaction at the negative electrode during the transition to region III. ing. The reason is as follows. This is because if the amount of hydrogen gas generated in the region II cannot be reduced, the increase in the battery internal pressure in the region II cannot be suppressed, and therefore liquid leakage during high load charging may not be prevented. Further, if the negative electrode cannot be promptly shifted to the oxygen gas consumption reaction at the time of transition to region III, the hydrogen gas generation reaction proceeds at the negative electrode and the oxygen gas generation reaction proceeds at the positive electrode in region III. To do. For this reason, an increase in the amount of gas generated in the region III is caused, so that it may not be possible to prevent liquid leakage during high-load charging.

  Embodiments of the present invention are shown below. In addition, this invention is not limited to embodiment shown below.

  FIG. 2 is a half sectional view of the alkaline dry battery according to the present embodiment. As shown in FIG. 2, a positive electrode 2 and a negative electrode 3 are accommodated in a bottomed cylindrical battery case 1 via a separator 4, and an alkaline electrolyte is injected. The opening of the battery case 1 is sealed with a negative electrode terminal plate 7 connected to each of the gasket 5 and the negative electrode current collector 6, and the outer surface of the battery case 1 is covered with an exterior label 8.

  In the negative electrode 3 in this embodiment, zinc alloy powder (negative electrode active material) is dispersed in a gel alkaline electrolyte. The zinc alloy powder contains mercury (such as aluminum, indium, or bismuth) that is free of mercury, cadmium, lead, or all of them, and that suppresses corrosion of zinc by the electrolytic solution. The zinc alloy powder may contain at least one metal of, for example, aluminum of 10 ppm to 50 ppm, bismuth of 50 ppm to 500 ppm, and indium of 200 ppm to 1000 ppm.

  The alkaline dry battery according to the present embodiment further includes the following configuration.

  The gel alkaline electrolyte in the present embodiment contains 0.00002 M parts by weight or more of quaternary ammonium salt with respect to 100 parts by weight of zinc alloy powder. As a result, when the oxygen gas generation reaction represented by the formula (4) is started at the positive electrode 2 during high-load charging (hereinafter, simply referred to as “when oxygen gas is generated at the positive electrode 2”), the negative electrode 3 Rapid transition from hydrogen gas generation reaction to oxygen gas consumption reaction. There are two possible reasons for this.

  The first reason is that the ammonium cation ionized from the quaternary ammonium salt is adsorbed on the surface of the zinc alloy powder, so that water molecules can be prevented from approaching the surface of the zinc alloy powder. From the measurement using a zeta electrometer, etc., it has been confirmed that the surface of the zinc alloy powder in the gel alkaline electrolyte is negatively charged. The quaternary ammonium salt is considered to be adsorbed on the surface of the zinc alloy powder because it becomes a cation in the gel alkaline electrolyte. Thereby, the hydrogen overvoltage at the surface of the zinc alloy powder increases. Therefore, compared with the case where the ammonium cation is not adsorbed on the surface of the zinc alloy powder, the hydrogen gas generation reaction is less likely to occur. Therefore, when oxygen gas is generated at the positive electrode 2, the negative electrode 3 quickly shifts from the hydrogen gas generation reaction to the oxygen gas consumption reaction.

  The second reason is that the zinc particles precipitated in the gel alkaline electrolyte to which the quaternary ammonium salt is added are precipitated in the gel alkaline electrolyte to which the quaternary ammonium salt is not added. It is because it is finer than that. Thereby, when the zinc electrodeposition reaction shown by Formula (2) occurs, the surface area of zinc increases. Here, the negative electrode reactions shown in the formulas (2), (3), and (5) all occur on the surface of zinc. Therefore, when oxygen gas is generated at the positive electrode 2, the larger the surface area of zinc, the easier the oxygen generated at the positive electrode 2 diffuses in the electrolyte as dissolved oxygen and reaches the surface of zinc on the negative electrode side. Therefore, in the negative electrode 3, it is easy to shift from the hydrogen gas generation reaction to the oxygen gas consumption reaction.

  For the above two reasons, if the gel alkaline electrolyte in the present embodiment contains 0.00002 M parts by weight or more of the quaternary ammonium salt with respect to 100 parts by weight of the zinc alloy powder, oxygen gas is generated at the positive electrode 2. At the same time, the negative electrode 3 quickly shifts from the hydrogen gas generation reaction to the oxygen gas consumption reaction. Thereby, it can be prevented that hydrogen gas is generated in the negative electrode 3 after oxygen gas is generated in the positive electrode 2. In addition, since the oxygen generated by the equation (4) can be consumed by the equation (5), the amount of oxygen gas remaining in the battery case 1 without being consumed by the negative electrode 3 can be reduced.

  The quaternary ammonium salt is desirably contained in the gel alkaline electrolyte at 0.00010 M parts by weight or less with respect to 100 parts by weight of the zinc alloy powder. Although the detailed mechanism is unknown, the present inventors have confirmed the tendency that the higher the concentration of the quaternary ammonium salt in the gel alkaline electrolyte, the more the amount of gas generated during normal storage. Therefore, the concentration of the quaternary ammonium salt in the gel alkaline electrolyte is desirably 0.00010 M parts by weight or less with respect to 100 parts by weight of the zinc alloy powder.

  The material of this quaternary ammonium salt is not particularly limited. However, the quaternary ammonium salt in this embodiment has 2 or more and 3 or less methyl groups and a linear alkyl group having 2 or more carbon atoms (hereinafter simply referred to as “linear alkyl group”). It is desirable that The reason can be considered as follows. If the quaternary ammonium salt has 2 or more and 3 or less methyl groups, the adsorption effect of the ammonium cation on the surface of the zinc alloy powder can be further enhanced. Moreover, if the quaternary ammonium salt has a linear alkyl group, the effect of inhibiting the access of water molecules to the surface of the zinc alloy powder can be further enhanced.

  Moreover, the alkaline electrolyte in the present embodiment and the alkaline electrolyte in the gel alkaline electrolyte contain 0.3 mol / l or more of a zinc compound (for example, zinc oxide). As a result, the amount of hydrogen gas generated in region II during high load charging can be reduced. The reason can be considered as follows.

  When a zinc compound is added to the alkaline electrolyte, zinc complex ions present in the alkaline electrolyte increase. Moreover, when a zinc compound is added to the gel alkaline electrolyte, the zinc complex ions present in the gel alkaline electrolyte increase. Thereby, it takes time to complete the reduction reaction of the zinc complex ion represented by the formula (2). That is, the region I can be extended for a long time. Here, since the transition time from the region II to the region III is when the potential of the positive electrode 2 reaches the oxygen generation potential, it is irrelevant to the concentration of the zinc compound in the alkaline electrolyte, and the gel alkaline electrolyte It is also independent of the concentration of the zinc compound in the alkaline electrolyte. Thus, when the zinc compound is added to the alkaline electrolyte and the gel alkaline electrolyte, the start time of the region III does not change in spite of the longer period of the region I, so the period of the region II is shortened. In region II, the amount of hydrogen gas generated increases with the lapse of time (L12 in FIG. 1 (a)). Therefore, the amount of hydrogen gas generated in region II can be reduced by shortening the period of region II. it can.

  In addition, if the alkaline electrolyte and the alkaline electrolyte in the gel alkaline electrolyte contain 0.3 mol / l or more of zinc compound, hydrogen gas is generated in the negative electrode 3 when oxygen gas is generated in the positive electrode 2. Immediate transition from the generation reaction to the oxygen gas consumption reaction. The reason can be considered as follows.

  Since zinc complex ions in the alkaline electrolyte and the gel alkaline electrolyte increase, the amount of zinc deposited by the reaction shown in the formula (2) increases, and the surface area of zinc may increase accordingly. Thereby, when oxygen gas is generated at the positive electrode 2, oxygen generated at the positive electrode 2 diffuses in the electrolyte as dissolved oxygen and easily reaches the zinc surface on the negative electrode 3 side. Immediate transition from the generation reaction to the oxygen gas consumption reaction.

  If the concentration of the zinc compound in the alkaline electrolyte and the alkaline electrolyte in the gel alkaline electrolyte exceeds 0.8 mol / l, there may be a problem such as a decrease in discharge performance. Therefore, it is desirable that the alkaline electrolyte and the alkaline electrolyte in the gel alkaline electrolyte contain 0.8 mol / l or less of the zinc compound.

  Usually, the gel-like alkaline electrolyte is a gelled alkaline electrolyte. Therefore, in the present embodiment, the concentration of the zinc compound in the alkaline electrolyte and the concentration of the zinc compound in the alkaline electrolyte in the gel alkaline electrolyte are substantially the same.

  Moreover, although the zinc oxide is illustrated as a zinc compound in the below-mentioned Example, zinc oxide is only an example of a zinc compound and a zinc compound is not limited to zinc oxide.

  The alkaline dry battery according to this embodiment preferably further has the following configuration.

The BET specific surface area of the zinc alloy powder in this embodiment is preferably 0.040 cm ² / g or more. As a result, during high load charging, oxygen gas generated at the positive electrode 2 diffuses in the electrolyte and easily reaches the surface of the zinc alloy powder. Transition. Therefore, compared with the case where the BET specific surface area of zinc alloy powder is less than 0.040 cm < ² > / g, generation | occurrence | production of the liquid leakage at the time of high load charge can be prevented.

If the BET specific surface area of the zinc alloy powder exceeds 0.045 cm ² / g, it will provide a lot of hydrogen generation fields due to the corrosion of zinc caused by the electrolyte. May cause an increase in the amount generated. Therefore, the BET specific surface area of the zinc alloy powder is more preferably 0.040 cm ² / g or more and 0.045 cm ² / g or less.

  A method for producing a zinc alloy powder having a desired BET specific surface area may be appropriately selected by those skilled in the art. For example, the particle diameter of the zinc alloy powder may be changed, or the ratio of the zinc alloy powder having a predetermined particle diameter may be changed.

  Moreover, it is desirable to use electrolytic manganese dioxide whose average valence of manganese is 3.95 or more as the positive electrode active material. When the average valence of manganese of manganese dioxide is increased, the oxidation reaction of manganese dioxide represented by the formula (1) can be terminated early at the time of high load charging, and therefore the termination time of region II can be advanced. . In the present embodiment, since the period of the region I is long as described above, the period of the region II can be further shortened by advancing the end time of the region II. As a result, it is possible to further reduce the amount of hydrogen gas generated in the region II, thereby further preventing an increase in the internal pressure of the battery during high load charging. Specifically, if the average valence of manganese in manganese dioxide is 3.95 or more, it is considered that the increase in battery internal pressure during high load charging can be suppressed.

  In addition, the alkaline electrolyte in the present embodiment and the alkaline electrolyte in the gel alkaline electrolyte are preferably 34% by weight or more of a potassium hydroxide aqueous solution. The higher the concentration of potassium hydroxide in the alkaline electrolyte and the higher concentration of potassium hydroxide in the alkaline electrolyte in the gel alkaline electrolyte, the higher the pH of each of the alkaline electrolyte and the gel alkaline electrolyte. During high load charging, the oxygen generation potential at the positive electrode 2 decreases. Thereby, the oxidation reaction of manganese dioxide represented by the formula (1) can be terminated early. In the present embodiment, since the period of the region I is long as described above, the period of the region II can be further shortened by advancing the end time of the region II. Therefore, the amount of hydrogen gas generated in region II can be further reduced. However, if the concentration of potassium hydroxide in the alkaline electrolyte and the concentration of potassium hydroxide in the alkaline electrolyte in the gel alkaline electrolyte exceeds 40% by weight, the ionic conductivity may be lowered. It may cause deterioration of pulse discharge characteristics. For these reasons, the alkaline electrolyte and the alkaline electrolyte in the gel alkaline electrolyte are more preferably 34 wt% or more and 40 wt% or less of an aqueous potassium hydroxide solution.

Further, when the alkaline battery according to the present embodiment is an AA alkaline battery, the volume of the air space in the battery case 1 (hereinafter simply referred to as “volume of the air space”) is 0.35 cm ³ or more. It is desirable to be. When the volume of the generated gas is the same, the increase in the internal pressure of the battery when hydrogen gas is generated can be suppressed as the volume of the air space increases. Therefore, as the volume of the air space is larger, the possibility that the battery will leak is further reduced. However, if the volume of the air space exceeds 0.70 cm ³ , the capacity of the alkaline battery may be reduced. Therefore, when the alkaline battery according to the present embodiment is an AA alkaline battery, it is more desirable that the volume of the air space is 0.35 cm ³ or more and 0.70 cm ³ or less.

For the same reason, when the alkaline battery of this embodiment is a AAA alkaline batteries, the volume of the air space desirably is 0.18 cm ³ or more, 0.18 cm ³ or more 0.36 cm ³ More desirable if:

  As a method for measuring the volume of the air space, a known method may be used.

  Although the alkaline dry battery according to the present embodiment has been described with a focus on the battery configuration, the following is a focus on the battery characteristics.

  When the alkaline battery according to this embodiment is an AA alkaline battery, T2−T1 ≦ 10 (min) is satisfied when the battery is charged with a constant current at 250 mA in a 20 ± 2 ° C. environment.

  When the alkaline battery according to this embodiment is a single-size alkaline battery, T2−T1 ≦ 10 (min) is satisfied when the battery is charged with a constant current at 100 mA in an environment of 20 ± 2 ° C.

  Considering that T2−T1 ≧ 30 (minutes) when a known alkaline dry battery is charged with a high load, the alkaline dry battery according to the present embodiment can shorten the period of region II, and from region II to region III. It can be said that the negative electrode 3 quickly shifts from the hydrogen gas generation reaction to the oxygen gas consumption reaction when it shifts to.

  In the following Examples 1 to 6, AA alkaline batteries will be described, but the present invention is not limited to AA alkaline batteries.

<Example 1>
In Example 1, the concentration of the quaternary ammonium salt in the gel alkaline electrolyte was changed, and the concentration of zinc oxide in the alkaline electrolyte in the alkaline electrolyte and the gel alkaline electrolyte was changed. Changed the BET specific surface area of the zinc alloy powder and examined the probability of occurrence of liquid leakage during high-load charging.

-Manufacturing method of alkaline battery-
First, the positive electrode 2 was produced. Electrolytic manganese dioxide and graphite were mixed at a weight ratio of 94: 6 to obtain a mixed powder. After adding 1 part by weight of the alkaline electrolyte to 100 parts by weight of the mixed powder, the mixture was stirred with a mixer to uniformly mix the mixed powder and the alkaline electrolyte, and sized to a fixed particle size. The granular material thus obtained was pressure-molded using a hollow cylindrical mold. This obtained the positive mix pellet.

  Here, HSO-TF manufactured by Tosoh Corporation was used as the electrolytic manganese dioxide, and SP-20 manufactured by Nippon Graphite Industries Co., Ltd. was used as the graphite. As alkaline electrolytes, three types of alkaline electrolytes having different zinc oxide concentrations were prepared. Specifically, zinc oxide was added to a 35 wt% potassium hydroxide aqueous solution so as to be 0.15 mol / l, 0.30 mol / l, and 0.45 mol / l.

  Next, a plurality of positive electrode mixture pellets were inserted into the battery case 1 and pressurized. As a result, the positive electrode material mixture pellets were brought into close contact with the inner surface of the battery case 1.

  A separator 4 wound in a columnar shape was inserted inside the positive electrode mixture pellet. Thereafter, the alkaline electrolyte in this example was injected for the purpose of wetting the separator 4 and the positive electrode mixture pellets. As the separator 4, a vinylon-lyocell composite nonwoven fabric manufactured by Kuraray Co., Ltd. was used.

Subsequently, the negative electrode 3 was produced. First, a zinc alloy powder containing Al: 0.003% by weight, Bi: 0.010% by weight, and In: 0.020% by weight was prepared by a gas atomization method. Next, the produced zinc alloy powder was classified using a sieve. Then, BET specific surface area so as to 0.039cm ² /g,0.040cm ² /g,0.043cm ² / g and 0.046cm ² / g, was prepared zinc alloy powder.

  This zinc alloy powder and a gel alkaline electrolyte were mixed to prepare a gelled negative electrode. As the gel alkaline electrolyte, three or four types of gel alkaline electrolytes having different concentrations of lauryltrimethylammonium chloride (quaternary ammonium salt) were prepared. Specifically, the gel-like alkaline electrolyte is composed of 54 parts by weight of alkaline electrolyte, 0.4 parts by weight of cross-linked polyacrylic acid, and cross-linked polyacrylic in this example with respect to 100 parts by weight of zinc alloy powder. Sodium sulfate 0.7 parts by weight was added, and lauryltrimethylammonium chloride (0 parts by weight), 0.00002 M parts by weight, 0.00010 M parts by weight, and 0.00014 M parts by weight were added. It is a thing. In this example, M is the molecular weight of lauryltrimethylammonium chloride. The gelled negative electrode thus produced was inserted into the separator 4. Thereafter, the battery case 1 was sealed using an assembly sealing body formed by integrating the gasket 5, the negative electrode current collector 6, and the negative electrode terminal plate 7. Thereby, the AA alkaline battery of Example 1 was produced.

  In this example and Examples 2 to 6 described later, the concentration of zinc oxide in the alkaline electrolyte and the concentration of zinc oxide in the alkaline electrolyte in the gel alkaline electrolyte were the same.

-Evaluation method for alkaline batteries-
Five batteries were prepared for each type of alkaline battery. Each battery was connected to a DC power source and charged for 2 hours at a charge rate of 250 mA. After charging, the occurrence rate (%) of liquid leakage was determined by visual confirmation. Hereinafter, this evaluation method is referred to as “leakage test during high load charging”.

-Results and discussion-
The results are shown in FIG. The “lauryltrimethylammonium chloride concentration” in FIG. 3 describes a number (mol) obtained by dividing the value of the parts by weight of lauryltrimethylammonium chloride with respect to 100 parts by weight of the zinc alloy powder by the molecular weight (FIG. 6 and FIG. 6). The same applies to FIG. 8). In addition, “Liquid leakage rate at the time of charging” in FIG. 3 describes the result of the liquid leakage test at the time of high load charging (the same applies to FIGS. 6 and 8).

  For example, no. When focusing on the batteries 1-1 to 1-3, the battery (No. 1) in which the concentration of the zinc compound in the alkaline electrolyte and the concentration of the zinc compound in the alkaline electrolyte in the gel alkaline electrolyte are 0.3 mol / l or more. In the battery of 1-2 to 1-3), the leakage occurrence rate at the time of high-load charging could be lowered as compared with the battery having the concentration of less than 0.3 mol / l (the battery of No. 1-1). This tendency is It was confirmed even in batteries other than the batteries 1-1 to 1-3. The reason is considered as described in the above embodiment.

  Also, for example, No. Focusing on the batteries 1-20, 1-23, 1-26, and 1-29, the amount of lauryltrimethylammonium chloride in the gelled alkaline electrolyte is 0.00002 M parts by weight or more with respect to 100 parts by weight of the zinc alloy powder. If the concentration was less than 0.00002 M parts by weight, the leak rate during high load charge was as high as 80%. This tendency is It was confirmed with batteries other than the batteries 1-20, 1-23, 1-26 and 1-29. The reason is considered as described in the above embodiment.

Furthermore, no. When focusing on the batteries of 1-2, 1-11, 1-23, and 1-32, if the BET specific surface area is 0.040 cm ² / g or more, the leakage rate at the time of high load charging is further reduced. I was able to. This tendency is It was able to confirm also in batteries other than the battery of 1-2, 1-11, 1-23, and 1-32. The reason is considered as described in the above embodiment.

<Example 2>
In Example 2, the manganese valence of manganese dioxide was changed to study further prevention of liquid leakage caused by high load charging.

-Manufacturing method of alkaline battery-
Except for the production method of the positive electrode 2 and the production method of the negative electrode 3, the alkaline dry battery of this example was produced according to the production method of the alkaline dry battery in Example 1 above.

  First, a method for manufacturing the positive electrode 2 will be described.

  Electrolytic manganese dioxide and graphite were mixed at a weight ratio of 94: 6 to obtain a mixed powder. After adding 1 part by weight of the alkaline electrolyte to 100 parts by weight of the mixed powder, the mixed powder and the electrolytic solution were uniformly mixed by stirring with a mixer, and sized to a constant particle size. The granular material thus obtained was pressure-molded using a hollow cylindrical mold. This obtained the positive mix pellet.

  Here, as the electrolytic manganese dioxide, four types of electrolytic manganese dioxide HH-PF, HH-PF oxidation treatment product, HH-TF, and HH-TF oxidation treatment product for alkaline dry batteries manufactured by Tosoh Corporation were used. The oxidized product has been subjected to the following treatment. Electrolytic manganese dioxide is added to a sulfuric acid aqueous solution at 60 ° C. and 10 wt% so that the concentration becomes 100 g / l. After stirring the slurry thus obtained at 60 ° C. for 1 hour, electrolytic manganese dioxide is filtered off, washed with water, neutralized with an aqueous sodium hydroxide solution and washed again with water to obtain electrolytic manganese dioxide having a high manganese valence. .

  The average manganese valence of the above four types of manganese dioxide was determined. The oxidation degree of manganese dioxide (sample) was measured by oxidation-reduction titration using oxalic acid, the amount of manganese was measured by chelate titration using EDTA, and the average valence of manganese was determined. When the average valence of manganese of each manganese dioxide was determined according to this method, the valences of HH-PF, HH-PF oxidation treated product, HH-TF and HH-TF oxidation treated product were 3.93, 3 and 3, respectively. .95, 3.96, 3.98.

  Moreover, as alkaline electrolyte, what added zinc oxide so that it might become 0.4 mol / l in 35 weight% potassium hydroxide aqueous solution was used.

  Next, a method for manufacturing the negative electrode 3 will be described.

The zinc alloy powder produced in Example 1 was prepared such that the BET specific surface area was 0.043 cm ² / g. This zinc alloy powder and a gel alkaline electrolyte were mixed to prepare a gelled negative electrode. The gel-like alkaline electrolyte is 54 parts by weight of alkaline electrolyte, 0.4 parts by weight of crosslinked polyacrylic acid, and 0.7 parts of crosslinked sodium polyacrylate in 100 parts by weight of zinc alloy powder. A part by weight is added, and 0.00006 M part by weight of lauryltrimethylammonium chloride (M is a molecular weight of lauryltrimethylammonium chloride) is further added.

-Evaluation method for alkaline batteries-
Five batteries were prepared for each type of alkaline dry battery, and a leak test during high-load charging and a leak test during storage were performed for each battery. In the leakage test during storage, the rate of occurrence of leakage (%) was obtained by visual confirmation after storage in an environment at 60 ° C. for 30 days.

  Furthermore, the battery charged in the leak test at the time of high load charge was cut open in water, gas in the battery case 1 was collected, and the volume was measured. When the battery internal pressure is calculated from the volume of the air space and the gas collection amount, the battery internal pressure reaches the operating pressure of the safety valve when the gas collection amount is 17 ml. Therefore, when the amount of gas collected is less than 17 ml, it can be considered that there is no risk of leakage. Furthermore, if the amount of gas collected is less than 13.5 ml, the internal pressure of the battery is 80% or less with respect to the operating pressure of the safety valve.

-Results and discussion-
The results are shown in FIG. In FIG. 4, “(a) Leakage rate during charging” describes the result of the leak test during high load charging, and “(b) Leakage rate during storage” The results of the leakage test during storage are described (the same applies to FIGS. 5 and 7).

  Both (a) the rate of leakage during charging and (b) the rate of leakage during storage were 0%. Furthermore, when the average valence of manganese was 3.95 or more, the amount of collected gas could be suppressed to less than 13.5 ml. The reason is considered as described in the above embodiment.

<Example 3>
In Example 3, the concentration of potassium hydroxide in the alkaline electrolyte and the concentration of potassium hydroxide in the alkaline electrolyte in the gel alkaline electrolyte were changed to examine further prevention of liquid leakage due to high load charging. did.

-Manufacturing method of alkaline battery-
The alkaline dry battery of this example was manufactured according to the alkaline dry battery manufacturing method of Example 1 above, except for the alkaline electrolyte manufacturing method and the negative electrode 3 manufacturing method.

  As the alkaline electrolyte, six types of alkaline electrolytes having different potassium hydroxide concentrations were used. Specifically, aqueous solutions containing 32 wt%, 34 wt%, 36 wt%, 38 wt%, 40 wt%, and 42 wt% potassium hydroxide were prepared. Each alkaline electrolyte contained 0.4 mol / l of zinc oxide.

  Next, a method for manufacturing the negative electrode 3 will be described.

The zinc alloy powder produced in Example 1 was prepared so that the BET specific surface area was 0.043 cm ² / g. This zinc alloy powder and a gel alkaline electrolyte were mixed to prepare a gelled negative electrode. The gel-like alkaline electrolyte is 54 parts by weight of alkaline electrolyte, 0.4 parts by weight of crosslinked polyacrylic acid, and 0.7 parts of crosslinked sodium polyacrylate in 100 parts by weight of zinc alloy powder. A part by weight is added, and 0.00006 M part by weight of lauryltrimethylammonium chloride (M is a molecular weight of lauryltrimethylammonium chloride) is further added.

-Evaluation method for alkaline batteries-
Five batteries were prepared for each type of alkaline battery. In the same manner as in Example 2, each battery was subjected to a leak test during high load charge and a leak test during storage, and after the leak test during high load charge was completed, The volume of gas present in was measured. Moreover, the following high load pulse discharge test was done with respect to each battery, and the average value was calculated | required.

  In the high-load pulse discharge test in this example, a cycle of discharging at 1.5 W for 2 seconds in an atmosphere of 20 ° C. and then discharging at 0.65 W for 28 seconds is defined as one cycle, and this is continuously performed per hour. It is to repeat the cycle. That is, the high-load pulse discharge test in this example is intermittent discharge in which discharge is performed for 5 minutes per hour and rested for 55 minutes. The number of pulses until the closed circuit voltage reached 1.05 V was examined.

-Results and discussion-
The results are shown in FIG.

  Both (a) the rate of leakage during charging and (b) the rate of leakage during storage were 0%. Furthermore, when the concentration of potassium hydroxide in the electrolytic solution was 34% by weight or more, the amount of collected gas could be suppressed to less than 13.5 ml. The reason is considered as described in the above embodiment.

  In the high-load pulse discharge test, the higher the potassium hydroxide concentration, the lower the number of pulses, that is, the discharge performance of the alkaline battery decreased.

  From these facts, when the concentration of potassium hydroxide in the alkaline electrolyte and the concentration of potassium hydroxide in the alkaline electrolyte in the gel alkaline electrolyte are 34 wt% or more and 40 wt% or less, the discharge performance is maintained. Furthermore, it was possible to further prevent the occurrence of liquid leakage during high load charging.

<Example 4>
In Example 4, suppression of hydrogen gas generation during storage was examined.

-Evaluation method for alkaline batteries-
AA alkaline batteries (No. 1-1 to 1-18 and No. 1-31 to 1-39) produced in Example 1 and a BET specific surface area of 0.045 cm ² / g. Five batteries (Nos. 4-1 to 4-9) prepared by the same method as in Example 1 above using the zinc alloy powder prepared as described above were prepared, respectively, in a 60 ° C. environment. And stored for 30 days, the occurrence rate (%) of liquid leakage was determined by visual confirmation. Furthermore, these batteries were dissected in water to collect the gas in the battery case 1, and the volume was measured.

-Results and discussion-
The results are shown in FIG.

  No leakage occurred in all batteries.

The amount of gas collected after storage was larger as the BET specific surface area of the zinc alloy powder was larger and as the concentration of lauryltrimethylammonium chloride in the gel alkaline electrolyte was higher. In particular, when the BET specific surface area was 0.046 cm ² / g, the amount of collected gas was greatly increased as compared with the case where the BET specific surface area was 0.045 cm ² / g. Further, if lauryltrimethylammonium chloride in the gel alkaline electrolyte is 0.00014 M parts by weight with respect to 100 parts by weight of the zinc alloy powder, the ammonium salt is 0.00010 M parts by weight with respect to 100 parts by weight of the zinc alloy powder. Compared with the case, the amount of collected gas was greatly increased. From these facts, it can be confirmed that the BET specific surface area of the zinc alloy powder is preferably 0.045 cm ² / g or less, and the gel-like alkaline electrolyte contains lauryltrimethylammonium chloride in 100 parts by weight of the zinc alloy powder. On the other hand, it was confirmed that it was desirable to have 0.00010M parts by weight or less.

<Example 5>
In Example 5, the material of the quaternary ammonium salt was changed, and further prevention of liquid leakage due to high load charging was studied.

-Manufacturing method of alkaline battery-
Except for the production method of the negative electrode 3, the alkaline dry battery of this example was produced according to the production method of the alkaline dry battery in Example 1 above. In addition, the alkaline electrolyte in a present Example is 35 weight% potassium hydroxide aqueous solution, and contains 0.4 mol / l zinc oxide.

A method for producing the negative electrode 3 will be described. The zinc alloy powder produced in Example 1 was prepared so that the BET specific surface area was 0.043 cm ² / g. This zinc alloy powder and a gel alkaline electrolyte were mixed to prepare a gelled negative electrode. The gel-like alkaline electrolyte is 54 parts by weight of alkaline electrolyte, 0.4 parts by weight of crosslinked polyacrylic acid, and 0.7 parts of crosslinked sodium polyacrylate in 100 parts by weight of zinc alloy powder. Part by weight was mixed, and 0.00006 M part by weight of quaternary ammonium salt (M is the molecular weight of each quaternary ammonium salt) was further added. Quaternary ammonium salts include seven types of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, diethyldimethylammonium hydroxide, decyltrimethylammonium chloride, lauryltrimethylammonium chloride and tetradecyltrimethylammonium chloride. Using.

-Evaluation method for alkaline batteries-
Using the same method as the evaluation method in Example 2, the alkaline dry battery in this example was evaluated.

-Results and discussion-
The results are shown in FIG.

  In any battery to which any quaternary ammonium salt was added, (a) the rate of leakage during charging and (b) the rate of leakage during storage was 0%. Further, when a quaternary ammonium salt in which 2 or more and 3 or less methyl groups and a linear alkyl group are bonded to a nitrogen atom is used as a quaternary ammonium salt (Nos. 5-4 to 5-7) In the case of (battery), the amount of gas collected could be suppressed to less than 13.5 ml. The reason is considered as described in the above embodiment.

Although details are omitted, when the volume of the air space is 0.35 cm ³ or more, the internal pressure of the battery can be reduced by 15% or more even if the gas collection amount is the same as the value shown in FIG. Therefore, it was confirmed that in the AA alkaline battery, the volume of the air space is desirably 0.35 cm ³ or more. In addition, in the AAA alkaline battery, it can be said that the volume of the air space is desirably 0.18 cm ³ or more for the same reason.

<Example 6>
In Example 6, the voltage behavior when the alkaline battery in Example 1 was charged was examined.

-Charging method for alkaline batteries-
The alkaline dry battery (the battery of No. 1-1 to 1-39) in Example 1 was charged with a constant current of 250 mA in a 20 ± 2 ° C. environment, and the battery voltage was monitored. Then, T1 (time from the start of charging until the battery voltage rises until the value reaches 2.2 V (minutes)), and T2 (from the start of charging through the generation stage of hydrogen gas, the battery voltage is 2.1 V). Time (min) until the time of decrease was measured.

-Results and discussion-
The results are shown in FIG.

  Batteries (No. 1-11, 1-12, 1-14, 1-15, 1-17, 1- 1) in which the occurrence rate of liquid leakage was 0% in the liquid leakage test during high load charging in Example 1 18, 1-23, 1-24, 1-26, 1-27, 1-29, 1-30, 1-32, 1-33, 1-35, 1-36, 1-38, and 1-39 Battery), T2-T1 was 10 minutes or less.

  On the other hand, the batteries (No. 1-1 to 1-10, 1-13, 1-16, 1-19 to 1-22, 1- 25, 1-28, 1-31, 1-34, and 1-37), T2-T1 exceeded 10 minutes.

  For these reasons, the AA alkaline battery in which no leakage occurred in Example 1 described above satisfies T2-T1 ≦ 10 (min) during constant current charging at 250 mA in an environment of 20 ± 2 ° C. It can also be said that.

  As described above, according to the present invention, even when an unused alkaline dry battery is charged by mistake, the amount of hydrogen gas generated can be reduced and the increase in battery internal pressure can be suppressed. Therefore, the present invention is effective for obtaining a highly reliable alkaline battery that is difficult to leak.

DESCRIPTION OF SYMBOLS 1 Battery case 2 Positive electrode 3 Negative electrode 4 Separator 5 Gasket 6 Negative electrode current collector 7 Negative electrode terminal board 8 Exterior label

Claims (9)

An alkaline dry battery comprising a positive electrode, a negative electrode, a separator, and at least an alkaline electrolyte retained in the separator,
The negative electrode includes a zinc alloy powder that is a negative electrode active material, and a gel alkaline electrolyte,
The gel alkaline electrolyte contains a quaternary ammonium salt in an amount of 0.00002 M parts by weight (M is the molecular weight of the quaternary ammonium salt) or more with respect to 100 parts by weight of the zinc alloy powder.
The alkaline electrolyte and the alkaline electrolyte in the gel alkaline electrolyte are alkaline batteries each containing a zinc compound in an amount of 0.3 mol / l or more. The alkaline dry battery according to claim 1, wherein the zinc alloy powder has a BET specific surface area of 0.040 cm ² / g or more. The positive electrode has electrolytic manganese dioxide as an active material,
The alkaline dry battery according to claim 1 or 2, wherein an average valence of manganese of the electrolytic manganese dioxide is 3.95 or more.   The alkaline electrolyte solution and the alkaline electrolyte solution in the gel alkaline electrolyte solution are 34 wt% or more and 40 wt% or less of an aqueous potassium hydroxide solution, respectively. Alkaline battery.   5. The alkaline dry battery according to claim 1, wherein the gel alkaline electrolyte contains a quaternary ammonium salt of 0.00010 M parts by weight or less with respect to 100 parts by weight of the zinc alloy powder. The quaternary ammonium salt is
A nitrogen atom,
2 or more and 3 or less methyl groups bonded to the nitrogen atom;
The alkaline dry battery according to any one of claims 1 to 5, comprising a linear alkyl group bonded to the nitrogen atom and having 2 or more carbon atoms. The alkaline dry battery according to claim 2, wherein the zinc alloy powder has a BET specific surface area of 0.045 cm ² / g or less. AA alkaline batteries
The positive electrode, the negative electrode, the separator and the alkaline electrolyte are housed in a battery case,
The alkaline dry battery according to any one of claims 1 to 7, wherein the volume of the air space of the battery case is 0.35 cm ³ or more. It is a AAA alkaline battery,
The positive electrode, the negative electrode, the separator and the alkaline electrolyte are housed in a battery case,
The alkaline dry battery according to any one of claims 1 to 7, wherein a volume of an air space of the battery case is 0.18 cm ³ or more.

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