JP2011181373A - Alkaline battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alkaline battery having a superior discharge characteristics. <P>SOLUTION: In the alkaline battery wherein a positive electrode 2 and a negative electrode 3 are housed in a battery case 1 via a separator 4, the positive electrode 2 includes electrolytic manganese dioxide and graphite. An electrical potential of the electrolytic manganese dioxide is set within a range of 290-340 mV to a reference electrode of mercury oxide (Hg/HgO), a filling density of the manganese dioxide in the positive electrode 2 is set within a range of 2.45-2.75 g/cm<SP>3</SP>, and the electrolytic manganese dioxide and the graphite are formed at a mass ratio of 92-96.5:8-3.5. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an alkaline battery, and more particularly to a positive electrode.

  Conventionally, for the purpose of improving the discharge performance of alkaline batteries, studies have been made to increase the battery voltage during discharge by using electrolytic manganese dioxide having a high potential to relatively increase the discharge duration. (See Patent Document 1).

  In addition, in the filling of manganese dioxide which is an active material of the positive electrode, studies on higher packing density have been made for the purpose of improving discharge performance. (See Patent Document 2).

  Moreover, the positive electrode is comprised by adding graphite powder for the purpose of improving electroconductivity with respect to these manganese dioxides.

JP 2004-137129 A Japanese Patent No. 3462877

  Today, the upper limit of the open circuit voltage of alkaline dry batteries often used for flashlights and toys is set to 1.65 V according to JIS standards and IEC standards. Many of the devices that use alkaline batteries as a power source are designed based on this rating.

  However, in the case where the high potential electrolytic manganese dioxide according to Patent Document 1 described above is used, the open circuit voltage of the alkaline dry battery exceeds 1.65V. . For example, in the case of a flashlight, the bean bulb filament may burn out, and in the case of a toy, abnormal heat generation may occur.

  Moreover, when using manganese dioxide with the high packing density which concerns on the patent document 2 mentioned above, there existed a possibility of increasing the damage to an apparatus.

  Furthermore, when a plurality of batteries are used in series, these problems are promoted, and there is room for improvement in terms of practicality.

  Then, this invention solves the said problem, and also aims at providing the alkaline battery which has the discharge characteristic superior to the past.

To achieve the above object, the present invention provides an alkaline battery in which a positive electrode and a negative electrode are housed in a battery case through a separator, the positive electrode includes electrolytic manganese dioxide and graphite, and oxidizes the potential of the electrolytic manganese dioxide. The mercury (Hg / HgO) reference electrode is in the range of 290 to 340 mV, and the manganese dioxide packing density of the positive electrode is in the range of 2.45 to 2.75 g / cm ³ .
The mass ratio between the electrolytic manganese dioxide and the graphite is 92 to 96.5: 8 to 3.5.

  By using high potential electrolytic manganese dioxide having a range of 290 to 340 mV with respect to a reference electrode of mercury oxide (Hg / HgO), the open circuit voltage of the battery can be increased.

Next, the packing density of manganese dioxide in the positive electrode is set to 2.45 to 2.75 g / cm ^3, and the internal resistance in the initial stage of discharge is increased by lowering the adhesion between the positive electrode and the battery case and between the particles constituting the positive electrode. The open circuit voltage is high, but the closed circuit voltage can be lowered. As a result, damage to the device can be reduced.

  However, in this state, the state in which the closed circuit voltage decreases continues until the end of discharge, and the operation time of the device is shortened. On the other hand, electrolytic manganese dioxide and graphite are preliminarily configured at a mass ratio in the range of 92 to 96.5: 8 to 3.5, and within the range of the packing density of manganese dioxide of the positive electrode, Due to the expansion, the adhesion between the positive electrode at the end of discharge and the battery case and between the particles constituting the positive electrode can be improved. In addition, it is possible to keep the closed circuit voltage high by suppressing an increase in internal resistance, and it is possible to extend the discharge duration.

  The expansion of the positive electrode during discharge is known to be significant in the height direction of the battery (between the terminals of both electrodes), but the graphite having lubricity and releasability in the positive electrode with a relatively low packing density. The presence of a certain amount of powder is considered to cause the positive electrode to expand three-dimensionally.

  In other words, it is possible to reduce the closed circuit voltage at the beginning of the discharge to alleviate damage to the device, and to suppress the decrease of the closed circuit voltage at the end of the discharge, thereby improving the discharge performance.

The half cross-sectional front view of the AA alkaline battery as one embodiment of the present invention Discharge duration until the closed-circuit voltage reaches 0.9 V and closed-circuit voltage at that time in a cycle in which the discharge of 4 minutes per hour is performed for 8 hours with 3.3Ω resistance of the batteries 3, 8, and 10 for 16 hours. Relationship diagram (A) Explanatory drawing in which electrolytic manganese dioxide grains and graphite grains are close-packed on the assumption that each has a uniform spherical shape, (b) An enlarged view of the main part

According to the present invention, in an alkaline battery in which a positive electrode and a negative electrode are housed in a battery case via a separator, the positive electrode includes electrolytic manganese dioxide and graphite, and the potential of the electrolytic manganese dioxide is expressed as mercury oxide (Hg / HgO). ) In the range of 290 to 340 mV, the manganese dioxide packing density of the positive electrode is in the range of 2.45 to 2.75 g / cm ³ , and the mass ratio of the electrolytic manganese dioxide to the graphite is 92 to By configuring in the range of 96.5: 8 to 3.5, it is possible to reduce the closed circuit voltage at the initial stage of the discharge to alleviate damage to the device, and to suppress the decrease of the closed circuit voltage at the end of the discharge to improve the discharge performance. This is an effect.

  Furthermore, by setting the potential of the electrolytic manganese dioxide within a range of 300 to 340 mV with respect to a mercury oxide (Hg / HgO) reference electrode, for example, when the battery is used in a miniature light bulb, it can be illuminated more brightly. .

  In addition, by making the average particle diameter of the electrolytic manganese dioxide 6.5 times or more than the average particle diameter of the graphite, the three-dimensional expansion of the positive electrode is promoted, and the discharge performance can be further improved.

  In addition, “manganese dioxide” having a predetermined packing density in the positive electrode in the present invention is manganese dioxide that functions as an active material filled in the positive electrode, and excludes other moisture and impurities. The packing density of manganese dioxide can be measured by the following method. First, regarding the measurement of the volume of the positive electrode, the inside of the battery is photographed with an X-ray fluoroscopic camera, and the positive electrode volume is calculated by measuring the outer diameter, inner diameter, and height of the positive electrode. Next, regarding the mass of manganese dioxide in the positive electrode, the battery was disassembled, the positive electrode 2 was completely taken out, sufficiently dissolved in acid, and the aqueous solution obtained by filtering the insoluble matter was analyzed by ICP emission spectrometry (high frequency inductively coupled plasma emission spectrometry). ) To check the manganese content contained in the solution. Next, the amount of manganese is converted into the amount of manganese dioxide, and the mass of manganese dioxide contained in the positive electrode of the battery is determined. By calculating the volume of the positive electrode and the mass of manganese dioxide filled in the positive electrode by this method, the manganese dioxide filling density in the positive electrode can be obtained.

  In addition, after constructing the battery, it is necessary to perform the above-described measurement after the alkaline electrolyte has spread throughout the battery. For example, the measurement may be performed after the battery is configured and stored at room temperature for 3 days, and the volume change of the positive electrode thereafter is slight and can be ignored.

  Further, the potential of electrolytic manganese dioxide with respect to the reference electrode of mercury oxide (Hg / HgO) can be measured by the following method. First, 20 g of electrolytic manganese dioxide is weighed using an upper pan balance and put into a 50 ml centrifuge tube. Next, 20 ml of 40 mass% potassium hydroxide aqueous solution is poured into the centrifuge tube, shaken lightly, sealed in the centrifuge tube, and stored at 20 ° C. for 24 hours. Next, a platinum electrode with a diameter of 0.5 mm is inserted so as to be in close contact with the solid part at the bottom of the centrifuge tube, and the tip of the mercury oxide (Hg / HgO) reference electrode is immersed in the supernatant of the centrifuge tube. The potential of electrolytic manganese dioxide with respect to the mercury oxide (Hg / HgO) reference electrode is measured by connecting the platinum electrode to the pole side and connecting the mercury oxide (Hg / HgO) reference electrode to the negative pole side and reading the voltage. be able to.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a half sectional front view of an AA alkaline battery (LR6) as an embodiment of the present invention.

  A hollow cylindrical positive electrode 2 is accommodated in a bottomed cylindrical battery case 1 that also serves as a positive electrode terminal and a positive electrode current collector. A negative electrode 3 is disposed in a hollow portion of the positive electrode 2 with a bottomed cylindrical separator 4 interposed therebetween. The opening of the battery case 1 accommodates the power generation elements such as the positive electrode 2 and the negative electrode 3, and then integrates the negative electrode terminal plate 7 electrically connected to the nail-type negative electrode current collector 6 and the resin sealing body 5. It is sealed by the assembly sealing body 9. The outer surface of the battery case 1 is covered with an exterior label 8.

  The electrolytic manganese dioxide constituting the positive electrode 2 preferably has an average particle size of 30 to 50 μm. By setting the average particle size of electrolytic manganese dioxide to 50 μm or less, the surface area of electrolytic manganese dioxide in the positive electrode can be increased, and the discharge performance can be improved. On the other hand, if the average particle size of electrolytic manganese dioxide is 30 μm or less, the positive electrode is difficult to be pressure-molded and productivity is deteriorated, which is not preferable. Therefore, it is preferable that an average particle diameter shall be 30-50 micrometers.

  The amount of Na in the positive electrode manganese dioxide is preferably 0.06% or less. Na in the electrolytic manganese dioxide inhibits the chemical reaction of the battery, and therefore suppresses the three-dimensional expansion of the positive electrode 2 during discharge. By reducing Na in the electrolytic manganese dioxide as much as possible, the chemical reaction of the battery can be promoted, the three-dimensional expansion of the positive electrode 2 can be further promoted, and the discharge performance can be improved. The graphite constituting the positive electrode 2 preferably has an average particle size of 6 to 10 μm. By setting the average particle size of graphite to 10 μm or less, the surface area of graphite in the positive electrode 2 can be increased, the conductivity of the positive electrode 2 can be improved, and the discharge performance can be improved. Further, if the average particle diameter of graphite is 6 μm or less, it is difficult to press-mold the positive electrode and productivity is deteriorated, which is not preferable. Therefore, the average particle size is preferably 6 to 10 μm. As the graphite having an average particle diameter of 6 to 10 μm, for example, graphite of SP-20M grade manufactured by Nippon Graphite Co., Ltd. may be used.

  In addition, the alkaline battery of the present invention may have an open circuit voltage of 1.65 V or higher when the battery is stored at room temperature (within a range of about 15 to 25 ° C.) for 1 week. Furthermore, it may be 1.67 or more.

  Examples of the present invention will be described in detail below, but the present invention is not limited to the examples shown below.

First, the problem of the present invention will be described with reference to Table 1 while describing a battery production method and an evaluation method. From the above-mentioned Patent Document 2, when a battery filled with manganese dioxide at a higher density of 2.90 g / cm ³ is prepared, good discharge performance is shown, but damage to the device becomes too large, The life may be shortened.

  Electrolytic manganese dioxide powder having a predetermined potential shown in Table 1 (hereinafter referred to as EMD potential in the table), graphite powder having an average particle size of 9 μm, 39% by mass of potassium hydroxide as an alkaline electrolyte, and An aqueous solution containing 2% by mass of zinc oxide and titanium oxyhydroxide powder were prepared.

  The total of the mass of the electrolytic manganese dioxide powder and the graphite powder of the positive electrode is 100%, and the mass ratio of the graphite powder is 2.5% shown in Table 1 (hereinafter referred to as the graphite mass ratio in the positive electrode in the table). In addition, with the total mass of the electrolytic manganese dioxide powder and the graphite powder being 100%, 1.5% of the alkaline electrolyte and 0.2% of titanium oxyhydroxide are added and sufficiently stirred. Compressed and molded into flakes. Next, the flaky positive electrode was pulverized into granules, classified by a sieve, and 10-100 mesh was pressed into a hollow cylinder to obtain a pellet-shaped positive electrode 2.

  In the gelling agent, polyacrylic acid powder as a thickening agent and cross-linked branched sodium polyacrylate powder as a water-absorbing polymer are used in combination, and the alkaline electrolyte and non-glazed zinc alloy powder are reduced to 0. The negative electrode 3 was obtained by mixing at a mass ratio of .26: 0.54: 35.2: 64.0. The zinc alloy powder used contained 0.025% by mass indium, 0.005% by mass bismuth, and 0.006% by mass aluminum, and had a volume average particle diameter of 130 μm.

  The resin sealing body 5 was obtained by injection molding 6,12 nylon into a predetermined size and shape.

  The external terminal plate 7 was obtained by pressing a nickel-plated steel plate having a thickness of 0.5 mm into a predetermined size and shape.

  The negative electrode current collector 6 was pressed using a brass wire rod so that the entire length was 37.0 mm and the diameter of the body portion was φ1.15, and the surface was plated with tin.

  For these, first, the negative electrode current collector 6 was electrically welded to the external terminal plate 7 and then press-fitted into the central through hole of the resin sealant 5 to produce an assembly sealant 9.

An AA alkaline battery having the structure shown in FIG. 1 was produced according to the following procedure. Two of the predetermined positive electrodes 2 obtained as described above were inserted into the battery case 1, and the positive electrode 2 was pressed with a pressurizing jig to be brought into close contact with the inner wall of the battery case 1. A bottomed cylindrical separator 4 was disposed in the center of the positive electrode 2 in close contact with the inner wall of the battery case 1. 1.55 g of an aqueous solution containing 33% by mass of potassium hydroxide and 2% by mass of zinc oxide was injected into the separator 4 as an alkaline electrolyte. After a predetermined time had passed, 6.2 g of the negative electrode 3 obtained above was filled in the separator 4. In addition, the separator 4 used the nonwoven fabric which mixed and mixed mainly the polyvinyl alcohol fiber and the rayon fiber. After the opening end of the battery case 1 is sealed with the assembly sealing body 9, the outer surface of the battery case 1 is covered with the exterior label 8, and the manganese dioxide density in the positive electrode 2 when stored as a battery (refer to the following table) in medium, expressed as Seikyokuchu MnO ₂ density) was obtained battery becomes 2.90 g / cm ³ bulk density shown in Table 1.

  Next, Table 1 shows the discharge performance, open circuit voltage, closed circuit voltage, and miniature bulb test results of these batteries.

  Here, the discharge performance is the discharge duration (minutes) until the closed circuit voltage reaches 0.9 V in a cycle in which discharge is performed for 4 minutes per hour for 8 hours with a resistance of 3.3Ω and pauses for 16 hours. .

  The open circuit voltage is a value measured after the battery was produced and stored at room temperature for 1 week. Note that the open circuit voltage of a general alkaline battery including the battery of the present invention decreases with time. For example, in the case of AA type, it is in the range of 0.002 to 0.005 per year, in the case of AA type, it is in the range of 0.004 to 0.01 per year, and in the case of AA type, it is one year. In the range of 0.01 to 0.015 per unit, if it is a single type, it tends to descend linearly in the range of 0.015 to 0.025 per year.

  The closed circuit voltage is the battery voltage after 1 second after applying a load of 3.3Ω after storing the battery at room temperature for 1 week after it was manufactured.

  In addition, the miniature light bulb test is to prepare 20 miniature light bulbs with a rating of 1.5V and 0.3A, and turn them on using one battery prepared for each, until the battery voltage drops and the miniature bulb turns off. In the meantime, it is a test to confirm how many of the 20 miniature light bulbs cut the filament.

  Table 1 shows the number of filament bulbs cut.

  As shown in Table 1, the discharge performance improves as the potential of electrolytic manganese dioxide increases. However, when a battery is produced with the positive manganese dioxide density using electrolytic manganese dioxide having a potential of 290 mV or higher, Damage is remarkable.

  Here, it was considered that the damage to the device was due to the closed circuit voltage being too high, and in order to reduce the closed circuit voltage, studies were made to reduce the packing density of manganese dioxide in the positive electrode 2. A battery similar to the battery 3 was prepared except that the packing density of manganese dioxide in the positive electrode 2 was changed as shown in Table 2, and the discharge performance, the open circuit voltage, the closed circuit voltage, and the result of the miniature light bulb test were shown for each battery. It was shown in 2.

As shown in Table 2, by setting the packing density of manganese dioxide of the positive electrode 2 to 2.45 to 2.75 g / cm ³ , the damage to the device is actually reduced from the result of the miniature light bulb test. I understand.

  This is because the adhesion between the positive electrode 2 and the battery case 1 and between the particles constituting the positive electrode 2 is reduced, and the open circuit voltage is high but the closed circuit voltage can be reduced by increasing the internal resistance in the initial stage of discharge. Inferred.

When the packing density of manganese dioxide in the positive electrode 2 is 2.90 / cm ³ or more, the close circuit voltage is high because the adhesion between the positive electrode 2 and the battery case 1 and between the particles constituting the positive electrode 2 is maintained. Therefore, as can be seen from the miniature light bulb test, the damage to the device increases, which is not preferable.

When the packing density of manganese dioxide of the positive electrode 2 is 2.30 g / cm ³ or less, the internal resistance is excessively increased and the discharge performance is extremely lowered, which is not preferable.

  However, in this state, the state of low adhesion continues between the positive electrode 2 and the battery case 1 and between the particles constituting the positive electrode 2 until the end of discharge, and the internal resistance remains high. Absent.

  On the other hand, the positive electrode 2 during discharge is known to have a significant expansion in the height direction of the battery (between the terminals of both electrodes). It is considered that the presence of the graphite powder having lubricity and releasability causes the positive electrode 2 to expand three-dimensionally. With this configuration, within the range of the packing density of manganese dioxide of the positive electrode 2 described above. It was considered that the adhesion between the positive electrode 2 at the end of discharge and the battery case 1 and between the particles constituting the positive electrode 2 can be improved by the expansion of the positive electrode 2 after discharge. Then, it was thought that the increase in internal resistance can be suppressed and the closed circuit voltage can be kept high, and the discharge duration can be extended.

  That is, it was considered that the circuit voltage was lowered at the initial stage of discharge to reduce the damage to the device, and the discharge performance was improved by suppressing the decrease of the circuit voltage at the end of the discharge.

  Therefore, a battery similar to the battery 6 was prepared except that the mass ratio of graphite in the positive electrode 2 was changed as shown in Table 3, and the discharge performance, open circuit voltage, closed circuit voltage, and miniature bulb test results for each battery. Are shown in Table 3.

  As shown in Table 3, when the graphite mass ratio of the positive electrode 2 was 3.5% to 8.0%, the discharge performance could be improved while the damage to the device was reduced.

Since the battery was manufactured with the packing density of manganese dioxide of the positive electrode 2 in the range of 2.45 to 2.75 g / cm ³ , damage to the equipment could be reduced.

  Further, the improvement in discharge performance is due to the expansion of the positive electrode 2 during discharge. The expansion of the positive electrode 2 during discharge is known to be conspicuous in the height direction of the battery (between the terminals of both electrodes). However, in the positive electrode 2 having a relatively low packing density, a certain amount of lubricity or separation is expected. It is considered that the positive electrode 2 is expanded three-dimensionally by the presence of the graphite powder having moldability. This three-dimensional expansion can improve the adhesion between the positive electrode 2 at the end of discharge and the battery case 1 and between the particles constituting the positive electrode 2. In addition, it is possible to keep the closed circuit voltage high by suppressing the increase in internal resistance at the end of discharge, and to improve the discharge duration.

  When the graphite mass ratio in the positive electrode 2 is 2.5% or less, since the mass ratio of graphite is too small, expansion during discharge is not three-dimensional, and expansion in the height direction of the battery becomes remarkable. Therefore, the adhesion between the positive electrode 2 and the battery case 1 and between the particles constituting the positive electrode 2 is not improved at the end of discharge, the increase in internal resistance cannot be suppressed, and the discharge performance is remarkably lowered.

  Further, when the graphite mass ratio of the positive electrode 2 is 10.0% or more, as can be seen from the miniature light bulb test, the closed circuit voltage at the initial stage of discharge becomes high due to the conductivity of the graphite in the positive electrode 2, and the device This is not preferable because the damage to the arm becomes large.

  Fig. 2 shows a cycle in which discharge is performed for 4 minutes per hour with 3.3Ω resistance of batteries 3, 8, and 10 for 8 hours, and the discharge duration until the closed-circuit voltage reaches 0.9 V and at that time Indicates the closed circuit voltage.

  From FIG. 2, it is possible to lower the closed circuit voltage at the initial stage of discharge by lowering the packing density of manganese dioxide in the positive electrode 2 and to increase the graphite mass ratio of the positive electrode 2 to increase the positive electrode 2 and the battery as the discharge proceeds. It can be seen that the adhesion between the cases 1 and between the particles constituting the positive electrode 2 is improved, and the discharge performance is improved.

As shown in Table 4, by producing a battery with a manganese dioxide filling density in the positive electrode 2 in the range of 2.45 to 2.75 g / cm ³ , the closed circuit voltage is lowered and damage to the equipment is reduced. In addition, by setting the graphite mass ratio of the positive electrode 2 to 3.5 to 8.0%, the positive electrode 2 is expanded three-dimensionally during discharge, and the positive electrode 2 and the battery case 1 at the end of discharge are formed as well as the positive electrode 2. The adhesion between the particles can be improved, and the increase in internal resistance can be suppressed at the end of discharge to keep the closed circuit voltage high, so that the discharge performance can be improved.

  When high-potential manganese dioxide is used by appropriately combining the manganese dioxide packing density in the positive electrode 2 and the graphite mass ratio of the positive electrode 2 to values within a range in which each can exert an effect (the open circuit voltage is reduced by configuring the battery). Even in the case of exceeding 1.65 V, it was possible to produce a battery that can reduce damage to the device, which has been a problem in the past, and can exhibit good discharge performance.

  Conventionally, studies have been made to increase the electrode density in order to improve the discharge performance of the battery, but surprisingly, the present invention suppresses the reactivity at the initial stage of the discharge even if the electrode density is decreased, and discharges. By improving the terminal reactivity, it was possible to extend the battery life.

  Moreover, when the brightness of the miniature light bulb was compared with respect to the batteries 21, 27, 36, and 37, compared to the battery 21, the batteries 27, 36, and 37 were able to cause the miniature light bulb to emit light brighter. Therefore, the potential of electrolytic manganese dioxide is preferably 300 to 340 mV. More preferably, it may be in the range of 320 to 340 mV.

Here, in FIG. 3A, it is assumed that the electrolytic manganese dioxide particles (hereinafter referred to as EMD particles) and the graphite particles are spherical, the EMD particles are closely packed, and the gaps are filled with graphite particles. A positive electrode model is shown, and FIG. 3B shows an enlarged view of the main part. Thus, it was thought that the three-dimensional expansion of the positive electrode 2 can be further promoted when the EMD grains are closely packed. In order for the graphite particles (mean particle size B) to be arranged in the gap when the EMD particles (mean particle size A) are closely packed, the radius B / 2 of the graphite particles is A√ from FIG. What is necessary is just to become smaller than 3 / 3-A / 2. Therefore, B / 2 <A√3 / 3−A / 2
When EMD is satisfied, EMD grains are closely packed. When the above formula is arranged, the following formula is obtained.

A> (3 / (2√3-3)) B
That is, it is preferable that the EMD particle size is 6.5 times or more of the graphite particle size.

  Therefore, for the purpose of further promoting the expansion of the positive electrode at the end of discharge, a battery similar to the battery 36 was produced except that the EMD average particle diameter and the graphite average particle diameter of the positive electrode 2 were changed as shown in Table 5, Table 5 shows the results of discharge performance, open circuit voltage, closed circuit voltage, and miniature bulb test.

  As shown in Table 5, better discharge performance was exhibited when the EMD average particle size was 6.5 times or more the graphite average particle size. This is because the three-dimensional expansion was further promoted when the EMD average particle size in the positive electrode 2 was 6.5 times or more the graphite average particle size.

  The alkaline battery of the present invention has excellent discharge characteristics and can be suitably used for any device using a dry battery as a power source.

DESCRIPTION OF SYMBOLS 1 Battery case 2 Positive electrode 3 Negative electrode 4 Separator 5 Resin sealing body 6 Negative electrode collector 7 Negative electrode terminal board 8 Exterior label 9 Assembly sealing body

Claims (5)

An alkaline battery in which a positive electrode and a negative electrode are housed in a battery case via a separator,
The positive electrode includes electrolytic manganese dioxide and graphite, and the potential of the electrolytic manganese dioxide is in a range of 290 to 340 mV with respect to a mercury oxide (Hg / HgO) reference electrode, and the packing density of the electrolytic manganese dioxide of the positive electrode is 2. An alkaline battery having a range of 45 to 2.75 g / cm ³ and comprising the electrolytic manganese dioxide and the graphite in a mass ratio of 92 to 96.5: 8 to 3.5. 2. The alkaline battery according to claim 1, wherein the electrolytic manganese dioxide has a potential of 300 to 340 mV with respect to a mercury oxide (Hg / HgO) reference electrode. 2. The alkaline battery according to claim 1, wherein an average particle diameter of the electrolytic manganese dioxide is 6.5 times or more of an average particle diameter of the graphite. The alkaline battery according to any one of claims 1 to 3, wherein an open circuit voltage when the battery is stored and stored for 1 week at room temperature is 1.65V or more. The alkaline battery according to any one of claims 1 to 3, wherein an open circuit voltage when the battery is stored and stored for 1 week at room temperature is 1.67 V or more.

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