JP2008282669A - Flat alkaline primary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive flat alkaline primary battery having large battery capacity and superior heat resistance. <P>SOLUTION: In the alkaline primary battery 1 wherein an opening 3a of a negative electrode can 3 is fitted in an opening 2a of a positive electrode can 2 and a separator 6 is arranged at an airtight space formed by sealing the positive electrode can 2 and negative electrode can 3 via a gasket 4 and a positive electrode mixing agent 5 in which nickel oxyhydroxide is a main component is arranged at a positive electrode side and a negative electrode mixing agent 7 in which zinc alloy powder is a main component is arranged at a negative electrode side and an alkaline electrolyte is filled up in the airtight space, the nickel oxyhydroxide of the positive electrode mixing agent 5 has a half width of 0.3 to 0.7 deg./2θ on a (001) plane at a powder X-ray diffraction pattern, and has a half width of 4.0 to 10.0 deg./2θ on a (101) plane. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a flat alkaline primary battery.

  A so-called button-shaped or coin-shaped flat alkaline primary battery is used as a power source for small electronic devices such as electronic wrist watches and portable electronic computers. The flat alkaline primary battery includes a battery in which the positive electrode active material is made of manganese dioxide and a battery made of silver oxide. These batteries are already widely used.

  A battery using silver oxide for the positive electrode is superior to a battery using manganese dioxide for the positive electrode in that the volume energy density is high. In addition, when silver oxide is used as the positive electrode active material and zinc is used as the negative electrode active material, the battery voltage becomes almost constant around 1.56 volts, so that a small electronic device having a final voltage of 1.2 volts or more. It is suitable as a power source for

  However, although silver oxide has high performance as a positive electrode mixture for batteries, it is expensive because silver, which is a noble metal, is the main component, and the price constantly fluctuates depending on the silver market, so it can reduce and stabilize production costs. It is a material that is difficult to use in planning.

  On the other hand, manganese dioxide has a price per mass that is about 1/200 of silver oxide, and is cheaper than silver oxide. However, when manganese dioxide is used as the positive electrode active material, there is a problem that the driving time of the device becomes extremely short compared to the case where other batteries are used due to the voltage drop caused by the discharge of manganese dioxide.

In order to improve the performance of the battery, it has been studied to add various additives to the positive electrode active material (for example, see Patent Document 1). Moreover, the alkaline battery which uses nickel oxyhydroxide as a positive electrode active material and improves battery voltage is manufactured (for example, refer patent document 2 and patent document 3).
JP 2003-234107 A (2nd to 3rd pages, FIG. 1) JP 2004-6092 A (2nd to 3rd pages, FIG. 1) Japanese Patent Laying-Open No. 2005-19349 (pages 2 to 4 and FIG. 1)

  However, the alkaline battery using nickel oxyhydroxide has a theoretical electric capacity per unit mass of nickel oxyhydroxide of 292 mAh / g, which is smaller than the theoretical electric capacity of manganese dioxide of 308 mAh / g (per manganese value). Therefore, it is difficult to improve the capacity. In addition, since nickel oxyhydroxide has lower thermal stability than silver oxide or manganese dioxide as a characteristic of the material itself, there is also a problem that heat resistance as a battery is lowered.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a flat alkaline primary battery that is inexpensive, has a large battery capacity, and is excellent in heat resistance.

In order to solve the above problems, the invention according to claim 1 is characterized in that the opening of the negative electrode can is fitted into the opening of the positive electrode can, and the positive electrode can and the negative electrode can are sealed through a gasket. A separator is disposed in the formed sealed space, a positive electrode mixture mainly composed of nickel oxyhydroxide is disposed on the positive electrode side with the separator interposed therebetween, and a negative electrode compound mainly composed of zinc alloy powder is disposed on the negative electrode side. A flat alkaline primary battery in which an agent is arranged and the sealed space is filled with an alkaline electrolyte, and the nickel oxyhydroxide of the positive electrode mixture has a half width of the surface in the powder X-ray diffraction pattern of 0.3 to 0 .7 deg. / 2θ, and the half width of the surface is 4.0 to 10.0 deg. The point is that it is / 2θ.

  The invention according to claim 2 is the flat alkaline primary battery according to claim 1, wherein the peak intensity attributed to the nickel oxyhydroxide surface of the positive electrode mixture is at least 5 times the peak intensity attributed to the surface. The gist is that it is 7 times or less.

  According to the first aspect of the present invention, the positive electrode active material of the flat alkaline primary battery is mainly composed of nickel oxyhydroxide, and the half width of the (001) plane in the X-ray diffraction pattern of the nickel oxyhydroxide powder is 0.3 deg. / 2θ or more, 0.7 deg. / 2θ or less, and the half width of the (101) plane is 4.0 deg. / 2θ or more, 10.0 deg. / 2θ or less. For this reason, since the filling amount can be increased by increasing the particle size of the nickel oxyhydroxide powder, the discharge capacity can be improved. Therefore, an inexpensive and highly reliable flat alkaline primary battery can be provided without using an expensive material for the positive electrode active material.

  According to the invention described in claim 2, the peak intensity attributed to the (001) plane of nickel oxyhydroxide as the negative electrode mixture is not less than 5 times and not more than 7 times the peak intensity attributed to the (101) plane. is there. For this reason, a flat alkaline primary battery having a high discharge capacity and excellent heat resistance can be provided.

Hereinafter, an embodiment embodying the present invention will be described.
FIG. 1 shows a cross-sectional view of a flat (button-shaped) alkaline primary battery 1. The flat alkaline primary battery 1 includes a bottomed cylindrical positive electrode can 2 and a covered cylindrical negative electrode can 3. The positive electrode can 2 has a structure in which nickel plating is applied to a copper plate, and also serves as a positive electrode terminal. On the other hand, the negative electrode can 3 is formed by pressing a clad material composed of three layers of an outer surface layer, a metal layer, and a current collector layer. The outer surface layer is made of nickel, and the metal layer is made of stainless steel (SUS). The current collector layer is made of copper.

The negative electrode can 3 has its circular opening 3a folded back. An annular gasket 4 made of nylon or the like is attached to the opening 3a.
The positive electrode can 2 is connected to the negative electrode can 3 by fitting the negative electrode can 3 fitted with the gasket 4 from the opening 2a side and caulking the opening 2a. By connecting the positive electrode can 2 and the negative electrode can 3 in this manner, a sealed space is formed between the positive electrode can 2 and the negative electrode can 3.

  In this sealed space, a positive electrode mixture 5, a separator 6, and a negative electrode mixture 7 are accommodated. The positive electrode mixture 5 and the negative electrode mixture 7 are respectively accommodated on the positive electrode can 2 side and the negative electrode can 3 side with the separator 6 interposed therebetween. The separator 6 is formed by punching a sheet having a two-layer structure of a microporous membrane 6a and a nonwoven fabric 6b into a circular shape. The sealed space is filled with an alkaline electrolyte.

  The positive electrode mixture 5 is made of nickel oxyhydroxide as a positive electrode active material, graphite as a conductive agent, sodium polyacrylate as a binder, and 40% potassium hydroxide as an electrolytic solution. It is formed as a lock.

FIG. 2 shows a typical example of a powder X-ray diffraction pattern of a nickel oxyhydroxide powder when measured with a powder X-ray diffractometer using CuKα rays as a radiation source. 2θ = 17.5-20.0 °
A peak on the (001) plane is observed in the vicinity, and a peak on the (101) plane is observed in the vicinity of 2θ = 33.8 to 44.7 °. The half width of this (001) plane peak is 0.3 deg. / 2θ or more and 0.7 deg. / 2θ or less is preferable. That is, the half width is 0.7 deg. By setting it to / 2θ or less, the particle diameter of the nickel oxyhydroxide is increased, and the filling amount into the battery can be increased, so that the discharge capacity can be increased. Further, the half width is 0.3 deg. It is industrially difficult to produce nickel oxyhydroxide less than / 2θ.

  Further, the full width at half maximum of the (101) plane in the powder X-ray diffraction pattern of the nickel oxyhydroxide powder is 4.0 deg. / 2θ or more, 10.0 deg. It is preferable to set it to / 2θ or less. That is, although the mechanism is not clear, the half width is set to 4.0 deg. When it is set to / 2θ or more, the binding property between the nickel oxyhydroxide powders improves due to the appropriate decrease in crystallinity and structural distortion. For this reason, since the binder compounding ratio in the positive electrode mixture can be reduced, the flat alkaline primary battery 1 having excellent discharge capacity can be provided. Also, the half width is 10.0 deg. When it is set to / 2θ or less, the particle diameter of nickel oxyhydroxide is increased, and the amount of filling into the battery can be increased. Therefore, the discharge capacity of the flat alkaline primary battery 1 can be increased.

  Moreover, it is preferable that the peak intensity attributed to the (001) plane of nickel oxyhydroxide is 5 to 7 times the peak intensity attributed to the (101) plane. When the peak intensity of the (001) plane is 5 times or more than the peak intensity of the (101) plane, the crystallinity of the (001) plane increases, so that the heat resistance of the nickel oxyhydroxide itself is improved and the heat resistance is excellent. A flat alkaline primary battery can be produced. In addition, it is difficult to manufacture industrially so that the peak intensity of the (001) plane exceeds 7 times the peak intensity of the (101) plane.

  In the negative electrode mixture 7, a zinc alloy powder can be used as the negative electrode active material, an aqueous sodium hydroxide solution can be used as the alkaline electrolyte, and carboxymethyl cellulose, zinc oxide, or the like can be used as a thickener for the electrolytic solution.

Next, Examples 1 to 7 and Comparative Examples 1 and 2 in which the powder X-ray pattern of nickel oxyhydroxide constituting the positive electrode mixture 5 was changed were produced and verified. Each Example and each Comparative Example will be described according to Table 1.
Example 1
The battery structure of the flat alkaline primary battery 1 is the structure shown in FIG. The negative electrode can 3 is formed by pressing the clad material having a thickness of 0.18 mm having a nickel outer surface layer, a metal layer made of SUS, and a current collector layer made of copper. did.

  The positive electrode mixture 5 is prepared by mixing graphite as a conductive agent, nickel oxyhydroxide as a positive electrode active material, sodium polyacrylate as a binder and an electrolytic solution with a blender, and pelletizing with a tableting machine. Molded into.

  The full width at half maximum of the (001) plane in the powder X-ray diffraction pattern of nickel oxyhydroxide is 0.5 deg. / 2θ, the half width of the (101) plane is 7 deg. The peak intensity attributed to the (001) plane was 6 times the peak intensity attributed to the (101) plane.

  Next, the positive electrode mixture 5 was inserted into the positive electrode can 2, and an alkaline electrolyte containing potassium hydroxide was injected to cause the positive electrode mixture 5 to absorb the alkaline electrolyte. Further, the separator 6 having the microporous membrane 6a and the nonwoven fabric 6b was loaded on the positive electrode mixture 5. Further, an alkaline electrolyte containing potassium hydroxide was dropped onto the separator 6 to impregnate the separator 6 with the alkaline electrolyte.

In the negative electrode mixture 7, a zinc alloy powder was used as the negative electrode active material, an aqueous sodium hydroxide solution was used as the alkaline electrolyte, carboxymethyl cellulose and zinc oxide were used as the thickener of the electrolytic solution, and these were mixed to form a gel-like mixture. . Further, this mixture was molded into a pellet to form a negative electrode mixture 7 and placed on the separator 6. And after attaching gasket 4 to opening 3a of negative electrode can 3 beforehand, negative electrode can 3 was covered on positive electrode can 2. Further, the negative electrode can 3 and the positive electrode can 2 were sealed by caulking to produce a flat alkaline primary battery 1.
(Example 2)
Example 2 has the same configuration as that of Example 1, but the half width of the (001) plane in the powder X-ray diffraction pattern of nickel oxyhydroxide is 0.3 deg. / 2θ.
(Example 3)
Example 3 has the same configuration as that of Example 1, but the half width of the (001) plane in the powder X-ray diffraction pattern of nickel oxyhydroxide is 0.7 deg. / 2θ.
Example 4
Example 4 has the same configuration as that of Example 1, but the full width at half maximum of the (101) plane in the powder X-ray diffraction pattern of nickel oxyhydroxide is 4.0 deg. / 2θ.
(Example 5)
Example 5 has the same configuration as that of Example 1, but the half-value width of the (101) plane in the powder X-ray diffraction pattern of nickel oxyhydroxide is 10.0 deg. / 2θ.
(Example 6)
Example 6 has the same configuration as that of Example 1, but the peak intensity attributed to the (001) plane of the powder X-ray diffraction pattern of nickel oxyhydroxide is five times the peak intensity attributed to the (101) plane. It was.
(Example 7)
Example 7 has the same configuration as Example 1, but the peak intensity attributed to the (001) plane in the powder X-ray diffraction pattern of nickel oxyhydroxide is 7 times the peak intensity attributed to the (101) plane. It was.
(Example 8)
Example 8 has the same configuration as that of Example 1, but the half width of the (001) plane in the powder X-ray diffraction pattern of nickel oxyhydroxide is 0.8 deg. / 2θ.
Example 9
Example 9 has the same configuration as that of Example 1, but the full width at half maximum of the (101) plane in the powder X-ray diffraction pattern of nickel oxyhydroxide is 3.0 deg. / 2θ.
(Example 10)
Example 10 has the same configuration as that of Example 1, but the half width of the (101) plane in the powder X-ray diffraction pattern of nickel oxyhydroxide is 11.0 deg. / 2θ.
(Example 11)
Example 11 has the same configuration as that of Example 1, but the peak intensity attributed to the (001) plane of the X-ray diffraction pattern of the nickel oxyhydroxide powder is four times the peak intensity attributed to the (101) plane. It was.
(Comparative Example 1)
Comparative Example 1 has the same configuration as that of Example 1, but the half width of the (001) plane in the powder X-ray diffraction pattern of nickel oxyhydroxide is 0.8 deg. / 2θ, and the half width of the (101) plane is 3 deg. / 2θ. The peak intensity attributed to the (001) plane was set to four times the peak intensity ratio attributed to the (101) plane.
(Comparative Example 2)
Comparative Example 2 has the same configuration as that of Example 1, but the half width of the (001) plane in the powder X-ray diffraction pattern of nickel oxyhydroxide is 0.8 deg. / 2θ, and the half width of the (101) plane is 11.0 deg. / 2θ. The peak intensity attributed to the (001) plane was set to four times the peak intensity attributed to the (101) plane.

Then, 110 flat alkaline primary batteries 1 of Examples 1 to 11 and Comparative Examples 1 and 2 described above were produced, respectively, and the following verification was performed.
Specifically, 10 batteries out of 110 are stored in a harsh environment of temperature 60 ° C. and humidity dry, and the presence or absence of swelling in the height direction (thickness direction) of the flat alkaline primary battery 100 after 100 days Investigated about. The evaluation results are shown in Table 1. Moreover, 100 batteries out of 110 were subjected to constant resistance discharge at 30 kΩ, and the discharge capacity (mAh) when the final voltage was 1.2 V were measured and shown in Table 1.

表１より、実施例１〜３と実施例８とを比較した場合、オキシ水酸化ニッケルの粉末Ｘ線回折パターンにおける（００１）面の半値幅を０．３〜０．７ｄｅｇ．／２θとすることで、放電容量に優れる扁平形アルカリ一次電池１を作製できたことがわかる。

From Table 1, when Examples 1-3 are compared with Example 8, the half-value width of the (001) plane in the powder X-ray diffraction pattern of nickel oxyhydroxide is 0.3-0.7 deg. It turns out that the flat alkaline primary battery 1 excellent in discharge capacity could be produced by setting to / 2θ.

  Moreover, when Example 1 and Examples 4-5 are compared with Examples 9-10, the half value width of the (101) plane in the powder X-ray diffraction pattern of nickel oxyhydroxide is 4.0 to 10.0 deg. . It turns out that the flat alkaline primary battery 1 excellent in discharge capacity could be produced by setting to / 2θ.

  Furthermore, when Example 1 and Examples 6-7 are compared with Example 11, the peak intensity attributed to the (001) plane of nickel oxyhydroxide is five times the peak intensity attributed to the (101) plane. It turns out that the flat alkaline primary battery 1 excellent in heat resistance was able to be manufactured by setting it as 7 times or less above.

Moreover, when Examples 1-7 are compared with Comparative Examples 1-2, the half-value width of the (001) plane is 0.3-0.7 deg. / 2θ, the full width at half maximum of the (101) plane is 4.0 to 10.0 deg. The flat alkaline primary battery 1 having excellent discharge capacity and excellent heat resistance could be produced by setting the peak intensity of / 2θ and the (001) plane to 5 to 7 times the peak intensity of the (101) plane. I understand. In addition, although the battery produced in Example 11 was confirmed to have a swelling of several tens of millimeters, the swollen height was slightly smaller than the hundreds of millimeters of swelling produced in the batteries of Comparative Examples 1 and 2. there were.

According to the above embodiment, the following effects can be obtained.
(1) In the said embodiment, the positive electrode active material of the flat alkaline primary battery 1 was comprised from nickel oxyhydroxide. Further, the half width of the (001) plane in the X-ray diffraction pattern of this nickel oxyhydroxide powder was 0.3 deg. / 2θ or more, 0.7 deg. / 2θ or less, and the half width of the (101) plane is 4.0 deg. / 2θ or more, 10.0 deg. / 2θ or less. Furthermore, the peak intensity attributed to the (001) plane of nickel oxyhydroxide was set to be 5 to 7 times the peak intensity attributed to the (101) plane. For this reason, since the filling amount can be increased by increasing the particle size of the nickel oxyhydroxide powder, the discharge capacity can be improved. In addition, by utilizing appropriate crystallinity reduction and distortion on the crystal structure, the binding property between the powders is increased, and the binder compounding ratio in the positive electrode mixture 5 is reduced. Since the nickel filling amount can be increased, the discharge capacity can be further improved. Thereby, the flat alkaline primary battery 1 suitable for a small electronic device having a relatively high end voltage can be produced without using expensive silver oxide as the positive electrode active material.

  (2) In the above embodiment, the peak intensity attributed to the (001) plane of nickel oxyhydroxide is further set to 5 times or more and 7 times or less of the peak intensity attributed to the (101) plane. For this reason, a flat alkaline primary battery excellent in heat resistance can be produced.

Sectional drawing of the flat alkaline primary battery of this embodiment. The powder X-ray-diffraction figure of nickel oxyhydroxide powder.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Flat alkaline primary battery, 2 ... Positive electrode can, 3 ... Negative electrode can, 2a, 3a ... Opening, 4 ... Gasket, 5 ... Positive electrode mixture, 6 ... Separator, 7 ... Negative electrode mixture.

Claims (2)

Fit the opening of the negative electrode can into the opening of the positive electrode can, place the separator in a sealed space formed by sealing the positive electrode can and the negative electrode can through a gasket, and sandwich the separator, A flat alkaline primary in which a positive electrode mixture mainly composed of nickel oxyhydroxide is arranged on the positive electrode side, a negative electrode mixture mainly composed of zinc alloy powder is arranged on the negative electrode side, and the sealed space is filled with an alkaline electrolyte. A battery,
The nickel oxyhydroxide of the positive electrode mixture has a half-width of (001) plane in a powder X-ray diffraction pattern of 0.3 to 0.7 deg. / 2θ and the half width of the (101) plane is 4.0 to 10.0 deg. A flat alkaline primary battery characterized by being / 2θ. The flat alkaline primary battery according to claim 1,
The flat alkaline primary battery, wherein the peak intensity attributed to the (001) plane of the nickel oxyhydroxide of the positive electrode mixture is 5 to 7 times the peak intensity attributed to the (101) plane.

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