JP2018116777A - Alkaline battery and manufacturing method of alkaline battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alkaline battery which has excellent high-temperature storage performance and long-term storage performance.SOLUTION: An inside-out type alkaline battery 1a is formed by arranging a positive electrode mixture 3 molded in an annular shape while including a cathode active material in a cylindrical battery can 2 with a bottom which also plays a role as a cathode electrode. The battery can has a plated layer 23 formed by a nickel cobalt alloy on a front surface of the inner surface. The positive electrode mixture includes a manganese dioxide of which an alkali base potential is equal to 270 mV or more and 290 mV or less as a cathode active material, and includes a conducting assistant made of graphite at a rate of 4 wt.% or more and 6 wt.% or less to the cathode active material.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an alkaline battery and a method for producing an alkaline battery.

  In an alkaline battery, an alkaline power generation element composed of a positive electrode mixture, a separator, and a negative electrode mixture is housed in a bottomed cylindrical metal battery can, and the opening of the battery can uses a resin sealing gasket And has a hermetically sealed structure. FIG. 1 shows the structure of the LR6 type alkaline battery 1. FIG. 1A is a vertical cross-sectional view when the extending direction of the cylindrical shaft 100 is set to the vertical direction or the vertical direction, and FIG. 1B is an enlarged view inside a circle 101 in FIG. The alkaline battery 1 has a so-called inside-out structure, a bottomed cylindrical metal battery can 2, a positive electrode mixture 3 molded into a ring shape (hereinafter also referred to as a ring core shape) similar to a ring core, A bottomed cylindrical separator 4 disposed inside the positive electrode mixture 3, a negative electrode gel 5 containing a zinc alloy and filled inside the separator 4, and a negative electrode current collector 6 inserted into the negative electrode gel 5 , Negative electrode terminal plate 7, sealing gasket 8 and the like. In this structure, the positive electrode mixture 3, the separator 4, and the negative electrode gel 5 form the power generation element of the alkaline battery 1 in the presence of the electrolytic solution.

  Here, when the vertical direction is defined with the bottom side of the battery can 2 as a lower side, the battery can 2 also serves as a battery case and functions as a positive electrode current collector by directly contacting the positive electrode mixture 3. A positive electrode terminal 9 is formed on the bottom surface of the battery can 2. The dish-like negative electrode terminal plate 7 is dish-shaped with a flange-like edge, and is caulked through a sealing gasket 8 at the opening of the battery can 2 with the bottom face up so that the dish is turned down.

  The rod-shaped negative electrode current collector 6 inserted into the negative electrode gel 5 is fixed upright by welding its upper end to the lower surface 7d of the dish-shaped negative electrode terminal plate 7. The sealing gasket 8 includes a disk-shaped partition wall portion 81 that partitions the inside of the battery can 2 up and down, a side wall portion 82 that stands upward on the outer peripheral edge of the partition wall portion 81, and a hollow cylinder formed at the center of the partition wall portion 81. This is an integrally molded product made of resin having a boss portion 83 in the form of a resin. The negative electrode current collector 6 is inserted into the hollow hole of the boss portion 83 of the sealing gasket 8, and when assembling the alkaline battery 1, the negative electrode terminal plate 7, the negative electrode current collector 6 and the sealing gasket 8 are combined in advance as a sealing body. Keep it. And while a sealing body is inserted in the opening end side of the battery can 2 in which the electric power generation element was accommodated, the diameter of the opening of the battery can 2 is reduced inward. As a result, the side wall 82 of the sealing gasket 8 is sandwiched between the opening edge of the battery can 2 and the flange-shaped edge of the negative electrode terminal plate 7, and the battery can 2 is sealed in a sealed state.

  In the partition wall portion 81 of the sealing gasket 8, a groove-like thin portion concentric with the boss portion 83 is formed in a region facing the negative electrode gel 5, and this thin portion is a pressure inside the battery can 2. When the gas rises abnormally, it breaks prior to other parts of the sealing gasket 8 and finally the gas that caused the internal pressure is released to the atmosphere through the vent hole 71 provided in the negative electrode terminal plate 7. It functions as an explosion-proof safety mechanism.

  By the way, since the inner surface of the battery can 2 is exposed to a strong alkaline electrolyte, the battery can 2 is made of nickel having a thickness of about 1.0 to 2.0 μm as shown in an enlarged view in FIG. (Ni) It consists of the steel plate 21 in which the plating layer 22 was formed, and the Ni plating layer 22 is arrange | positioned at the inner surface side of the battery can 2 at least. As a result, iron constituting the steel plate 21 is prevented from being corroded by the strong alkaline electrolyte.

  In Patent Document 1 below, by forming a coating containing cobalt (Co) in the form of a metal or a compound on the inner surface side of the positive electrode can, the contact resistance between the electrode can and the positive electrode mixture can be increased for a long time. A technique for maintaining a low state is described. Patent Document 2 below describes a battery can of an alkaline battery in which a nickel cobalt (Ni—Co) alloy plating layer is formed on the inner surface side of the battery can. And the following nonpatent literature 1 describes the preparation procedure of an alkaline battery.

Japanese Patent Publication No. 7-70320 JP 2012-48958 A

FDK Co., Ltd., “Until Fujitsu Alkaline Batteries are Made”, [online], [Search on December 13, 2016], Internet <URL: http://www.fdk.co.jp/denchi_club/denchi_story/arukari. htm>

  As described above, in the inside-out type alkaline battery, the inner surface of the battery can 2 is plated with Ni. However, in an alkaline battery using a battery can whose inner surface is plated with Ni, if it is stored in a high temperature environment such as 60 ° C. that is close to the upper limit temperature of use, Ni is oxidized and the conductivity is lowered, and the discharge performance is deteriorated. There's a problem. Therefore, it is conceivable to provide a plating layer made of an alloy containing Co that does not decrease in conductivity even when oxidized. In the battery can described in Patent Document 2, Ni—Co is formed on the surface layer of the steel plate on which Ni plating is applied. A plating layer made of an alloy is further provided to optimize the thickness of the plating layer and the ratio of Co in the Ni—Co alloy.

  By the way, in recent years, general-purpose batteries such as alkaline batteries have been used for storage as well as emergency foods as power sources for flashlights, radios, and other electrical appliances and electronic devices. It has become. However, unlike emergency food, batteries cannot be consumed immediately and replaced with new stockpiles even when the expiry date is near. That is, when the expiration date of the battery approaches, the battery used in the electric appliances and electronic devices used in daily life is not always consumed conveniently. Therefore, alkaline batteries have been required to have long-term storage performance that can be used as a power source for each device even after being stored for a longer period (for example, 10 years) than an emergency meal with a storage period of about 5 years.

  Therefore, the present inventor examined the long-term storage performance of an alkaline battery using a battery can having a Ni—Co plating layer on the inner surface layer excellent in storage characteristics under a high temperature environment (hereinafter also referred to as high temperature storage performance). As a result, when stored for an extremely long period of time, it was found that Co in the plating layer was gradually eluted into the electrolyte, and the eluted Co ions reacted with zinc in the negative electrode to generate hydrogen gas. The hydrogen gas generated in the battery can increases the pressure in the battery can and may lead to leakage in some cases. And the leaked alkaline battery cannot be used as a power source of an electronic device or an electric appliance, as a matter of course.

  Then, this invention aims at providing the alkaline battery excellent in high temperature storage performance and long-term storage performance, and its manufacturing method.

In order to achieve the above object, the present invention provides an inside-out type in which a positive electrode mixture formed in an annular shape containing a positive electrode active material is disposed in a bottomed cylindrical battery can also serving as a positive electrode current collector. An alkaline battery,
The battery can has a plating layer made of a nickel-cobalt alloy on the inner surface.
The positive electrode mixture contains manganese dioxide having an alkali base potential of 270 mV or more and 290 mV or less as a positive electrode active material, and a conductive additive made of graphite is 4 wt% or more and 6 wt% or less with respect to the positive electrode active material. Is included in the proportion of
The alkaline battery is characterized by this. It is more preferable that the graphite is expanded graphite.

The present invention also includes a method for producing an alkaline battery, and the method for producing the alkaline battery comprises:
A manufacturing method of an inside-out type alkaline battery in which a positive electrode mixture formed into a ring including a positive electrode active material is disposed in a bottomed cylindrical battery can also serving as a positive electrode current collector,
In the bottomed cylindrical battery can that also serves as the positive electrode current collector, the annular positive electrode mixture and the negative electrode gel disposed through the separator inside the positive electrode mixture together with the alkaline electrolyte While storing the rod-shaped negative electrode current collector connected to the lower surface of the disk-shaped negative electrode terminal plate, the battery can be opened through a sealing gasket while being inserted into the negative electrode gel in an upright direction. An assembly step of assembling the alkaline battery by sealing with the negative electrode terminal plate, and an aging step of leaving the alkaline battery after assembly at a predetermined temperature higher than room temperature for a predetermined time,
In the assembly step, a battery can in which a plating layer made of a nickel cobalt alloy is formed on the inner surface layer, manganese dioxide having an alkali base potential of 270 mV to 290 mV as a positive electrode active material, and a conductive additive made of graphite Using a positive electrode mixture contained in a proportion of 4 wt% or more and 6 wt% or less with respect to the positive electrode active material,
In the aging step, the cobalt in the nickel cobalt alloy in the battery can is oxidized.
It is set as the manufacturing method of the alkaline battery characterized by the above-mentioned.

  According to the alkaline battery of the present invention, long-term storage performance can be improved while having excellent high-temperature storage performance. Moreover, according to the method for producing an alkaline battery of the present invention, the long-term storage performance of the alkaline battery can be further improved.

It is a figure which shows the structure of a general alkaline battery. It is a figure which shows the structure of the alkaline battery which concerns on the Example of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that in the drawings used for the following description, the same or similar parts may be denoted by the same reference numerals and redundant description may be omitted. In some drawings, reference numerals may be assigned to parts that are not required in other drawings if unnecessary.

=== Technical thought in the embodiment of the present invention ===
As described above, in an alkaline battery using a battery can in which a Ni plating layer is formed on the inner surface layer, Ni is oxidized and the conductivity of the battery can is reduced when stored in a high temperature environment. In an alkaline battery using a battery can in which a plating layer made of a Ni—Co alloy (hereinafter also referred to as a Ni—Co plating layer) is formed on the inner surface layer, the conductivity is reduced even if the inner surface of the battery can is oxidized. do not do. However, even an alkaline battery using a battery can having a Ni—Co plating layer may leak when stored for an extremely long period of time, such as 10 years or longer.

  Therefore, as a result of intensive studies to improve the long-term storage performance of an alkaline battery using a battery can having a Ni—Co plating layer formed on the inner surface layer, the present inventor has found that manganese dioxide in the positive electrode mixture There is a correlation between the potential with respect to the alkaline electrolyte (hereinafter also referred to as alkali-based potential) and the amount of graphite added to the discharge performance after storage in a high-temperature environment (hereinafter referred to as high-temperature storage performance) and long-term storage performance. I found out that there was. The present invention has been made based on such knowledge.

=== Embodiment of the Invention ===
FIG. 2 shows the structure of an alkaline battery 1a according to an example of the present invention. 2A is a longitudinal sectional view of the alkaline battery 1a, and FIG. 2B is an enlarged view of a circle 102 in FIG. The basic structure of the alkaline battery 1a is the same as that of the general alkaline battery 1 shown in FIG. 1, but in the alkaline battery 1a of the present embodiment, the Ni—Co plating layer is formed on the surface layer of the inner surface of the battery can 2a. 2B, as shown in FIG. 2B, the metal material constituting the battery can 2a is made of a steel plate 21 on which the Ni plating layer 22 is formed as a base material, and Ni is formed on the surface layer of the base material. -Co plating layer 23 is formed. A Ni plating layer 22 and a Ni—Co plating layer 23 are formed at least on the inner surface side of the battery can 2a.

  Further, in the alkaline battery 1a of this example, the alkali base potential of manganese dioxide in the positive electrode mixture 3 and the amount of graphite added as a conductive additive in the positive electrode mixture 3 are optimized. Thereby, the alkaline battery 1a of the present embodiment has excellent high-temperature storage performance and long-term storage performance.

== Sample ===
In order to evaluate the high-temperature storage performance and long-term storage performance of the alkaline battery 1a of this example, various alkaline batteries 1a having different preparation conditions for the positive electrode mixture 3 were prepared as samples. Further, as shown in FIG. 1, an alkaline battery 1 including a battery can 2 made of a steel plate 21 having only a Ni plating layer 22 formed on the surface layer was also prepared as a sample. The battery can (2, 2a) is basically a sample in which a Ni plating layer 22 having a thickness of about 1.5 μm is formed using a steel plate 21 having a thickness of about 0.15 mm as a base material. Accordingly, a Ni—Co plating layer 23 having a thickness of about 0.2 μm is formed on the surface of the Ni plating layer 22.

  Depending on the sample, the positive electrode mixture 3 is an alkaline base potential of electrolytic manganese dioxide (hereinafter also referred to as EMD) which is a positive electrode active material, the kind of graphite added to the positive electrode mixture and the conductive auxiliary agent, and the addition of the conductive auxiliary agent I changed the amount. The alkali base potential in each sample was adjusted by reducing EMD having an initial alkali base potential of 290 mV in solutions having different pHs.

=== Reliability test ===
In order to evaluate the high-temperature storage performance and long-term storage performance of various samples with different configurations of the battery can (2, 2a) and the preparation conditions of the positive electrode mixture 3, the discharge performance when each sample is stored in a high-temperature environment A test was conducted to examine the stability of the liquid and the presence or absence of leakage when stored at room temperature for a long time. Here, 10 individuals were prepared for each sample, and a high temperature storage test was performed in which all individuals were stored at a temperature of 60 ° C. for 2 months. Similarly, 10 individuals were prepared for each sample, and a long-term storage test was performed in which all individuals were stored at a temperature of 80 ° C. for 4 months.

  For the high temperature storage test, the change in discharge performance before and after the test was examined. Specifically, each sample was discharged for 2 seconds at a power consumption of 1.5 W and then discharged for 28 seconds at a power consumption of 650 mW as one cycle, and 10 cycles (5 minutes) continuously for 1 hour. After discharging, the test was paused for 55 minutes, and a pulse discharge test was repeated in which the operation of discharging again 10 cycles in the next 1 hour was repeated. The number of cycles to reach a final voltage of 1.05 V was measured. Moreover, the long-term storage test which preserve | saves a sample for 4 months at 80 degreeC is equivalent to preserve | saving for 13 years at normal temperature, and confirms the presence or absence of liquid leakage visually about each sample after a long-term storage test, and belongs to each sample Among the 10 individuals, the number of individuals in which leakage occurred was counted.

  Table 1 below shows the preparation conditions of each sample and the results of the high-temperature storage test and long-term storage test for each sample.

表１において、サンプル１〜５は、図１に示したアルカリ電池１のように、Ｎｉ−Ｃｏメッキ層２３がない電池缶２を用いたサンプルであり、他のサンプル６〜２２は、図２に示した、Ｎｉメッキ層２２の表層にＮｉ−Ｃｏメッキ層２３が内面に形成された電池缶２ａを用いている。またサンプル１〜１５とサンプル１６〜２２では、導電助剤に用いる黒鉛の種類が異なっており、サンプル１〜１５は導電助剤として一般的に使用されている粒径１５μｍ程度の人工黒鉛を用いており、サンプル１６〜２２はアスペクト比が大きく長径が４０μｍ程度まで伸張された膨張黒鉛を用いている。

In Table 1, samples 1 to 5 are samples using the battery can 2 without the Ni—Co plating layer 23 like the alkaline battery 1 shown in FIG. 1, and the other samples 6 to 22 are those shown in FIG. The battery can 2a having the Ni-Co plating layer 23 formed on the inner surface as the surface layer of the Ni plating layer 22 is used. Samples 1 to 15 and Samples 16 to 22 are different in the type of graphite used for the conductive assistant, and Samples 1 to 15 use artificial graphite having a particle size of about 15 μm, which is generally used as a conductive assistant. Samples 16 to 22 use expanded graphite having a large aspect ratio and a major axis extended to about 40 μm.

  “Annealing” in the table means that the steel plate material used for the battery can (2, 2a), that is, the steel plate 21 on which the plating layers (22, 23) are formed is heat-treated at a predetermined temperature and time (for example, 650). The battery can (2, 2a) is usually made using a steel sheet material that has been annealed. Here, except for samples 21 and 22, battery cans (2, 2a) made of a steel plate material that was all annealed were used.

  From Table 1, first, in Samples 1 to 5 using the battery can 2 having only the Ni plating layer 22 on the inner surface, the discharge in the initial state increases as the alkaline base potential of the EMD (“EMD potential” in the table) increases. The performance was excellent. However, the discharge performance after the high-temperature storage test was about 10 to 20% of the initial discharge performance, and it was found that the discharge performance was greatly deteriorated. On the other hand, in Samples 6 to 22 using the battery can 2a having the Ni—Co plating layer 23 on the inner surface, the discharge characteristics of 50% or more were maintained at least before and after the high temperature storage test. And from the samples 6 to 10 having the same kind and added amount of graphite but different only in the alkali base potential, if the alkali base potential is 270 mV or more and 290 mV or less, the discharge performance is 80% or more of the initial state even after the high temperature storage test. I knew it would be maintained. However, in Samples 9 and 10 having an alkali base potential of 260 mV or less, the discharge performance after the high-temperature storage test was 66% and 54%, respectively, before the test. In other samples 6 to 8, the discharge performance after the test was 80% or more with respect to the initial state, so samples 9 and 10 using an EMD with an alkali base potential of 260 mV or less as the positive electrode mixture were relatively It was found that the high-temperature storage performance was inferior. Samples 9 and 10 were individuals in which leakage occurred after a long-term storage test. As described above, the alkaline battery 1a of the present example uses the battery can 2a having the Ni—Co plating layer formed on the inner surface layer, and the alkaline base potential of the EMD contained in the positive electrode mixture 3 as the positive electrode active material is 270 mV. The condition is that it is 290 mV or less.

  Next, samples 11 to 15 have an alkali base potential of 280 mV, and artificial graphite is used as a conductive additive. And the addition amount of the artificial graphite is different. In addition, the addition amount of artificial graphite is a mass ratio with respect to EMD. In Samples 11 to 15, in Sample 15 in which the amount of artificial graphite added was 3 wt%, the discharge performance after the high-temperature storage test was 50% or less than that before the test. In addition, in Samples 11 and 12 having an addition amount of 8 wt% or more, there was an individual in which leakage occurred after a long-term storage test. From the above, it is desirable that the amount of graphite used as a conductive aid is 4 wt% or more and 6 wt% or less. And from the results of the high-temperature storage test and the long-term storage test in Samples 1 to 16, the alkaline battery 1a according to the example of the present invention has a battery can 2a having a Ni—Co plating layer on the inner surface layer and an alkaline base potential. EMD of 270 mV or more and 290 mV or less is used as a positive electrode active material, and a positive electrode mixture 3 in which graphite serving as a conductive auxiliary agent is added at a ratio of 4 wt% to 6 wt% with respect to the positive electrode active material; Become. And according to the alkaline battery 1a of a present Example, the discharge characteristic is maintained before and after high temperature storage, and even if it preserve | saves for a very long period, a leak does not generate | occur | produce, but it has the outstanding high temperature storage performance and long term storage performance.

  In addition, in Samples 16 to 20 in which expanded conductive graphite was used instead of artificial graphite as a conductive auxiliary agent for Samples 11 to 15, in Sample 20 in which the amount of expanded graphite serving as a conductive auxiliary agent was 3 wt%, after the high-temperature storage test The discharge performance was 59% compared to before the test. On the other hand, samples 16 to 19 in which the amount of expanded graphite added was 4 wt% maintained discharge performance of 87% to 94%. However, in Samples 16 and 17 to which 8 wt% or more of expanded graphite was added, there were individuals in which leakage occurred after a long-term storage test. Therefore, even if the graphite is expanded graphite, the optimum addition amount is not less than 4 wt% and not more than 6 wt%. When comparing sample 13 and sample 18 and sample 14 and sample 19 that differ only in the type of graphite, samples 18 and 19 in which graphite is expanded graphite are in an initial state compared to samples 13 and 14 using artificial graphite. The discharge performance after the high-temperature storage test was excellent. Therefore, the alkaline battery 1a of the present embodiment is more preferable if the conductive additive contained in the positive electrode mixture 3 is expanded graphite. Samples 21 and 22 use a battery can 2a made of a steel plate material that has not been annealed. The conditions for producing the positive electrode mixture 3 are the same as those of the samples 18 and 19, respectively. And although samples 18 and 19 using battery cans 2a made of annealed steel plate materials had better discharge characteristics after the initial stage and after the high temperature storage test, they had a discharge performance of 80% or more before and after the high temperature storage test. It was maintained, and no liquid leakage due to a long-term storage test occurred. That is, in the alkaline battery 1a of the present embodiment, the battery can 2a made of a steel plate material that has not been annealed may be used as long as the Ni—Co plating layer is formed on the inner surface.

  Here, considering the reason why Samples 6 to 8, 13, 14, 18, 19, 21, and 22 showed excellent high-temperature storage performance and long-term storage performance, first, regarding long-term storage performance, the alkaline base potential of EMD Therefore, it can be considered that Co is more easily oxidized, thereby promoting the oxidation of Co and making it difficult to elute Co and thus exhibiting excellent high-temperature storage performance. In addition, these samples are optimized for the addition of graphite, which has water repellency and low affinity with alkaline electrolytes, so that Co oxidation is not hindered and discharge is performed before and after the high-temperature storage test. It can be considered that the performance is maintained.

=== About Manufacturing Method of Alkaline Battery ===
From the test results shown in Table 1, while using the battery can 2a made of the steel plate 21 having the Ni-Co plating layer 23 formed on the inner surface, the EMD has an alkali base potential of 270 mV to 290 mV, and graphite. The alkaline battery 1a using the positive electrode mixture 3 to which 4 wt% or more and 6 wt% or less of EMD is added has excellent high-temperature storage performance and long-term storage performance. And there is a possibility that the long-term storage performance can be further improved by promoting the oxidation of Co. Therefore, by performing an aging treatment for performing heat treatment on the assembled alkaline battery 1a, the oxidation of Co in the Ni—Co plating layer 23 formed on the inner surface of the battery can 2a is further promoted, and long-term storage performance is achieved. Tried to further improve.

  Here, the alkaline battery 1a produced on the same conditions as the samples 7 and 18 in Table 1 and the alkaline battery 1a which performed the aging process which preserve | saves the said samples 7 and 18 at the temperature of 45 degreeC for 24 hours were produced as a sample. . In addition, for each sample, ten individuals were prepared for each of the high-temperature storage test and the long-term storage test. And the high-temperature storage performance and long-term storage performance with and without aging treatment were investigated. Since the prepared sample is expected to have excellent long-term storage performance like Samples 7 and 18, if no leakage occurs after the test, the sample after the test is submerged in water. The gas in the battery can was collected by water displacement, and the amount of the gas was measured.

  Table 2 below shows the effect of the aging treatment.

表２において、サンプル２３と２４は、それぞれ表１におけるサンプル７とサンプル１８と同じ条件で作製されたアルカリ電池１ａである。そして、サンプル２３および２４と同じ条件で作製されたアルカリ電池１ａに対してエージング処理を行ったアルカリ電池１ａがサンプル２５および２６である。表２に示したように、高温貯蔵性能は、初期特性においてはエージング処理によって１．５％程度低下し、試験後では、１％程度の低下であった。したがって、エージング処理の有無に依らず、高温貯蔵性能はほとんど影響を受けないと言える。一方、長期保存試験については、いずれのサンプルでも試験後に漏液が発生した個体はなかった。しかし、長期保存試験後のガス発生量は、エージング処理を施すことで、ガスの発生量が３０％〜３５％程度減少することが分かった。すなわち、エージング処理によって長期保存性能をさらに向上させることが確認できた。

In Table 2, samples 23 and 24 are alkaline batteries 1a produced under the same conditions as Sample 7 and Sample 18 in Table 1, respectively. Samples 25 and 26 are alkaline batteries 1a obtained by performing an aging treatment on alkaline batteries 1a manufactured under the same conditions as those of samples 23 and 24. As shown in Table 2, the high-temperature storage performance was reduced by about 1.5% by the aging treatment in the initial characteristics, and was reduced by about 1% after the test. Therefore, it can be said that the high-temperature storage performance is hardly affected regardless of the presence or absence of the aging treatment. On the other hand, in the long-term storage test, none of the samples had any leakage after the test. However, the amount of gas generated after the long-term storage test was found to be reduced by about 30% to 35% by performing aging treatment. That is, it was confirmed that the long-term storage performance was further improved by the aging treatment.

  As for the aging treatment, the higher the temperature and the longer the time, the more the Co oxidation of the Ni—Co plating layer in the battery can is promoted. However, on the other hand, the high-temperature storage performance may be deteriorated. Therefore, what is necessary is just to set the temperature and time in an aging process suitably according to the target high-temperature storage performance.

1,1a alkaline battery, 2,2a battery can, 3 positive electrode mixture, 4 separator,
5 Negative gel, 6 Negative current collector, 7 Negative terminal plate, 8 Sealing gasket,
9 positive terminal, 21 steel plate, 22 Ni plating layer, 23 Ni-Co plating layer

Claims (3)

An inside-out type alkaline battery in which a positive electrode mixture formed in an annular shape containing a positive electrode active material is disposed in a bottomed cylindrical battery can also serving as a positive electrode current collector,
The battery can has a plating layer made of a nickel-cobalt alloy on the inner surface.
The positive electrode mixture contains manganese dioxide having an alkali base potential of 270 mV or more and 290 mV or less as a positive electrode active material, and a conductive additive made of graphite is 4 wt% or more and 6 wt% or less with respect to the positive electrode active material. Included in percentage,
An alkaline battery characterized by that.   2. The alkaline battery according to claim 1, wherein the graphite is expanded graphite. A manufacturing method of an inside-out type alkaline battery in which a positive electrode mixture formed into a ring including a positive electrode active material is disposed in a bottomed cylindrical battery can also serving as a positive electrode current collector,
In the bottomed cylindrical battery can that also serves as the positive electrode current collector, the annular positive electrode mixture and the negative electrode gel disposed through the separator inside the positive electrode mixture together with the alkaline electrolyte While storing the rod-shaped negative electrode current collector connected to the lower surface of the disk-shaped negative electrode terminal plate, the battery can be opened through a sealing gasket while being inserted into the negative electrode gel in an upright direction. An assembly step of assembling the alkaline battery by sealing with the negative electrode terminal plate, and an aging step of leaving the alkaline battery after assembly at a predetermined temperature higher than room temperature for a predetermined time,
In the assembly step, a battery can in which a plating layer made of a nickel cobalt alloy is formed on the inner surface layer, manganese dioxide having an alkali base potential of 270 mV to 290 mV as a positive electrode active material, and a conductive additive made of graphite Using a positive electrode mixture contained in a proportion of 4 wt% or more and 6 wt% or less with respect to the positive electrode active material,
In the aging step, the cobalt in the nickel cobalt alloy in the battery can is oxidized.
The manufacturing method of the alkaline battery characterized by the above-mentioned.

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