JP2006185848A - Alkaline dry cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alkaline dry cell excellent in strong load discharge characteristics and with reliability enhanced by restraining gas generation. <P>SOLUTION: Of the alkaline dry cell 10 filled with a ring-shaped cathode mixture 21 containing manganese dioxide and nickel oxyhydroxide as a cathode active material in a cathode can 11, a content of the nickel oxyhydroxide contained in the cathode mixture 21 is to be zero or selectively small at an end part of the opening side of the cathode can 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an alkaline battery using manganese dioxide and nickel oxyhydroxide as a positive electrode active material.

  In alkaline manganese batteries such as LR, a circular positive electrode (positive electrode mixture, positive electrode core) is loaded in a bottomed cylindrical positive electrode can, a cylindrical separator is placed inside the positive electrode, and a gel is placed inside the separator. A negative electrode (negative electrode gel) is filled, and the opening of the positive electrode can is sealed with a negative electrode terminal plate and a gasket. As the positive electrode, one containing manganese dioxide as a positive electrode active material has been used.

  On the other hand, in recent years, the load (power consumption) of a device using a battery (battery-utilizing device) has increased, and a battery having excellent heavy load discharge characteristics has been demanded. Recently, battery-powered devices with a built-in voltage stabilizing function such as a DC-DC inverter have increased. However, in such devices, the absolute power generation capacity is more than the electromotive force characteristics (voltage characteristics) of the battery. Quantity is preferred.

Then, the alkaline dry battery which improved the heavy load discharge characteristic by mixing nickel oxyhydroxide in a positive electrode mixture came to be provided (for example, refer patent document 1).
JP2003-234107A

  However, alkaline dry batteries in which nickel oxyhydroxide is mixed in the positive electrode mixture have excellent high-load discharge characteristics, but compared to conventional alkaline batteries that use only manganese dioxide as the positive electrode active material, Therefore, the present inventors have made it clear that there is a problem that gas is easily generated. This gas generation causes battery leakage and greatly impairs battery reliability.

  Here, according to what the present inventors have learned, in an alkaline dry battery using nickel oxyhydroxide as a positive electrode active material, the nickel oxyhydroxide contained in the positive electrode mixture becomes a negative electrode (negative electrode gel) for some reason. It has been found that mixing causes gas generation.

  Further, it has been found that the gas generation is likely to occur when a part of the positive electrode mixture loaded in the positive electrode can moves to the negative electrode side. The positive electrode mixture and the negative electrode are separated by a separator. For example, part of the positive electrode mixture may be mixed into the negative electrode as powder or dust due to vibration during the manufacturing process or line conveyance. It is done. Even if the contamination is very slight, depending on the storage conditions, it may cause gas generation to the extent that leakage occurs.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an alkaline dry battery that has excellent heavy load discharge characteristics and is less likely to generate gas and has improved reliability.

  Other objects and configurations of the present invention will become apparent from the description of the present specification and the accompanying drawings.

The present invention provides the following means.
(1) An annular positive electrode containing manganese dioxide and nickel oxyhydroxide as a positive electrode active material is loaded into a bottomed cylindrical positive electrode can, and a cylindrical separator is disposed inside the positive electrode. In an alkaline battery filled with a gelled negative electrode and the opening of the positive electrode can sealed with a negative electrode terminal plate and a gasket, the content of nickel oxyhydroxide contained in the positive electrode is the opening side of the positive electrode can. An alkaline battery characterized in that it is zero or selectively small at the end.

In the above means (1), the following means are particularly suitable as an embodiment.
(2) In the above means (1), the positive electrode is composed of a plurality of annular positive cores loaded in a stacked manner in the positive electrode can, and the positive electrode core contains nickel oxyhydroxide positioned at the end of the positive electrode can An alkaline battery characterized in that the amount is less than zero or other positive electrode cores.

(3) In any one of the above means (1) or (2), the positive electrode is composed of a plurality of annular positive cores loaded in a stacked manner in a positive electrode can, and the positive core oxywater located at both ends of the stacked layers An alkaline dry battery characterized in that the content of nickel oxide is less than that of a positive electrode core at zero or other positions.

(4) In any one of the above means (1) to (3), the content of nickel oxyhydroxide contained in the positive electrode core is 30% or less at the end on the opening side of the positive electrode can. Alkaline battery. An alkaline dry battery characterized in that nickel oxyhydroxide contains cobalt and zinc.

(5) The alkaline dry battery according to any one of the above means (1) to (4), wherein the nickel oxyhydroxide contains cobalt and zinc.

  By the above means, it is possible to reliably prevent gas generation due to mixing of nickel oxyhydroxide in the positive electrode mixture into the negative electrode, thereby improving the high load discharge characteristics and making gas generation difficult. An alkaline dry battery with improved reliability can be provided.

  Operations / effects other than those described above will be apparent from the description of the present specification and the accompanying drawings.

  FIG. 1 shows an embodiment of an alkaline battery according to the present invention. In the alkaline dry battery 10 shown in the figure, an annular positive electrode mixture 21 is loaded in a bottomed cylindrical metal positive electrode can 11, and a cylindrical separator 22 is disposed inside the positive electrode mixture 21. Is filled with a gelled negative electrode (negative electrode gel) 23 and the opening of the positive electrode can 11 is sealed with a negative electrode terminal plate 25 and a gasket 26. The negative electrode current collector 24 protruding from the negative electrode terminal plate 25 is penetrated into the negative electrode 23.

  The positive electrode can 11 is a bottomed cylindrical container using a nickel-plated steel plate and serves as a positive electrode current collector and a positive electrode terminal. The positive electrode mixture 21 is stacked and formed by three positive electrode cores 21A, 21B, and 21B.

  The positive electrode cores 21A, 21B, and 21B include a first positive electrode core 21A that includes only manganese dioxide as a positive electrode active material and does not include nickel oxyhydroxide, and includes nickel oxyhydroxide as a positive electrode active material. The second positive electrode core 21B containing cobalt and zinc but not containing manganese dioxide is used. A first positive electrode core 21A is disposed at the end portion of the positive electrode can 11 at the opening side, and a second positive electrode core 21B is disposed at the middle portion and the bottom side of the positive electrode can 11. Yes.

  By including nickel oxyhydroxide as the active material of the positive electrode mixture 21, the alkaline dry battery 10 can have better load discharge characteristics than the alkaline dry battery using only manganese dioxide as the active material.

  In addition, in the manufacturing process of the alkaline battery 10, a part of the positive electrode core 21 </ b> A located at the opening side end of the positive electrode can 11, in particular, the surface portion may move to the negative electrode 23 side in the form of powder or dust. Although it is conceivable, since the positive electrode core 21A does not contain nickel oxyhydroxide, it is possible to effectively prevent gas generation due to the mixing of nickel oxyhydroxide into the negative electrode 23.

  As a result, it is possible to manufacture a highly reliable alkaline dry battery that has excellent heavy load discharge characteristics and hardly generates gas. This gas generation prevention effect can also be obtained by reducing the content of nickel oxyhydroxide at the opening side end of the positive electrode can 11.

  FIG. 2 shows another embodiment of the present invention. When a plurality of positive electrode cores are stacked in the positive electrode can 11, as shown in (a) of the figure, first positive electrode cores 21A are arranged at both ends of the stacked layers, and the second positive electrode cores are arranged in the middle. 21B may be arranged. Further, as shown in FIG. 5B, two first positive electrode cores 21A are stacked on the side close to the opening of the positive electrode can 11, and the second positive electrode core 21B is disposed on the bottom side of the positive electrode can 11. May be arranged.

  FIG. 3 shows yet another embodiment of the present invention. When the positive electrode mixture 21 is composed of a four-layer positive electrode core, the first positive electrode core 21A and the second positive electrode core 21B are effectively arranged as shown in (a) to (d) of FIG. is there.

[Example 1]
The following two types of positive electrode cores A and B were prepared, and eight types of cylindrical alkaline batteries (Nos. 1 to 8) were prepared by combining these two types of stacking orders.

Positive electrode core A: 90% by weight of manganese dioxide, 5% by weight of graphite as a conductive agent, 0.2% by weight of binder, and 4.8% by weight of 40% KOH aqueous solution were mixed. This was rolled with a roller compactor to form a sheet, which was then crushed and sieved. This was molded into a core shape using a mold.
Positive electrode core B: 90% by weight of nickel oxyhydroxide containing cobalt and zinc, 5% by weight of graphite as a conductive agent, 0.2% by weight of binder, and 4.8% by weight of 40% KOH aqueous solution were mixed. This was molded into a core shape in the same manner as the mixture A.

A positive electrode mixture in which three of the above two types of positive electrode cores A and / or B are stacked in a positive electrode can is formed, and eight types of alkaline dry batteries (No. ~ 8) were produced.

  Each of the eight types of batteries (Nos. 1 to 8) produced was tested in a high temperature and high humidity atmosphere at 60 ° C. and 90% (RH). In this test, the reliability of each battery (No. 1 to 8) was evaluated based on the number of batteries that had leaked up to the 40th day of storage.

  As a result, as shown in Table 1, in the batteries (Nos. 1 to 4) in which the positive electrode core B containing nickel oxyhydroxide is arranged on the opening side of the positive electrode can, liquid leakage occurred with high probability. In the battery (Nos. 5 to 8) in which the positive electrode core A not containing nickel oxyhydroxide is disposed on the opening side of the positive electrode can, it was found that there was no leakage during the storage test and the reliability was high.

[Example 2]
The following three types of positive electrode cores A, B, and C were prepared, and seven types of cylindrical alkaline batteries were produced by combining these three types.
Positive electrode core A: produced in the same manner as the positive electrode core A of Example 1.
Positive electrode core B: produced in the same manner as the positive electrode core B of Example 1.
Positive electrode core C: 45% by weight of nickel oxyhydroxide containing cobalt and zinc, 45% by weight of manganese dioxide, 5% by weight of graphite as a conductive agent, 0.2% by weight of binder, 4.8% by weight of 40% KOH aqueous solution % Was mixed. In the same manner as the positive electrodes A and B, this was rolled with a roller compactor to form a sheet, and then crushed and sieved. This was molded into a core shape using a mold.

A positive electrode mixture in which four positive electrode cores A and / or B or C are stacked in a positive electrode can is formed, and seven types of alkaline dry batteries (No. 1) are combined as shown in Table 2 depending on the combination of the stacking order. ~ 7) were produced.

  Each of the prepared seven types of batteries (Nos. 1 to 7) was subjected to a storage test for 40 days under a high temperature and high humidity condition of 60 ° C. and 90% RH. When the reliability of each battery (No. 1 to 7) was evaluated by the number of batteries that had leaked up to the 40th day of storage, as shown in Table 2, the oxyhydroxide was formed on the opening side of the positive electrode can. In all of the batteries (Nos. 1 to 4) in which the positive electrode core B containing nickel was disposed, liquid leakage occurred with a high probability, but the positive electrode core A not containing nickel oxyhydroxide was arranged on the opening side of the positive electrode can. In the batteries (Nos. 5 to 7), it was found that there was no leakage during the storage test and the reliability was high.

[Example 3]
As shown in Table 3, alkaline dry batteries with different proportions of nickel oxyhydroxide contained in the positive electrode core located on the opening side of the positive electrode can were prepared, and the temperature was kept at 60 ° C. and 90% RH for 40 days. A storage test was conducted. For other positive electrode cores not located on the opening side of the positive electrode can, the positive electrode core B of Examples 1 and 2 was used.

  As shown in Table 3, it can be seen that as the proportion of nickel oxyhydroxide in the positive electrode core located on the opening side of the positive electrode can increases, the number of liquid leaks during the storage test increases. However, when the proportion of nickel oxyhydroxide was 30% or less, no battery leaked during the storage test. From this, the proportion of nickel oxyhydroxide in the positive electrode core located on the opening side of the positive electrode can does not have to be zero, but is preferably 30% or less.

  As described above, the present invention has been described based on the typical embodiments. However, the present invention can have various modes other than those described above. For example, a mode in which the content of nickel oxyhydroxide is changed in the positive electrode core and the side where the content becomes zero or less is positioned on the opening side of the positive electrode can is also possible.

  It is possible to provide an alkaline dry battery that has excellent heavy load discharge characteristics and is less likely to generate gas and has improved reliability.

It is sectional drawing which shows one Embodiment of the alkaline dry battery which concerns on this invention. It is sectional drawing which shows another embodiment of the alkaline dry battery which concerns on this invention. It is sectional drawing which shows another embodiment of the alkaline dry battery which concerns on this invention.

Explanation of symbols

10 Alkaline battery 11 Positive electrode can 21 Positive electrode (positive electrode mixture, positive electrode core)
22 Separator 23 Gelled negative electrode (negative electrode gel)
24 Negative Current Collector 25 Negative Terminal Plate 26 Gasket 21A Positive Core 21B Positive Core

Claims (5)

  An annular positive electrode containing manganese dioxide and nickel oxyhydroxide as a positive electrode active material is loaded into a bottomed cylindrical positive electrode can, a cylindrical separator is disposed inside the positive electrode, and a gelled negative electrode is disposed inside the separator. In the alkaline dry battery in which the opening of the positive electrode can is sealed using a negative electrode terminal plate and a gasket, the content of nickel oxyhydroxide contained in the positive electrode is at the opening side end of the positive electrode can. Alkaline batteries characterized by zero or selectively low.   In Claim 1, the positive electrode is composed of a plurality of annular positive cores loaded in a stack in the positive electrode can, and the content of nickel oxyhydroxide in the positive electrode core located at the opening side end of the positive electrode can is zero or An alkaline battery characterized in that it has fewer than the positive electrode cores at other positions.   3. The positive electrode according to claim 1, wherein the positive electrode is composed of a plurality of annular positive electrode cores stacked in a positive electrode can, and the nickel oxyhydroxide content of the positive electrode cores located at both ends of the stack is zero. Alternatively, the alkaline battery is characterized in that it is less than the positive electrode cores at other positions.   4. The alkaline dry battery according to claim 1, wherein the content of nickel oxyhydroxide contained in the positive electrode core is 30% or less at an end portion on the opening side of the positive electrode can. 5. 5. The alkaline dry battery according to claim 1, wherein the nickel oxyhydroxide contains cobalt and zinc.

Images