JP6876442B2 - Alkaline battery, manufacturing method of alkaline battery - Google Patents

Description

The present invention relates to alkaline batteries and methods for manufacturing alkaline batteries.

Alkaline batteries contain an alkaline power generation element consisting of a positive electrode mixture, a separator, and a negative electrode mixture in a bottomed cylindrical metal battery can, and the opening of the battery can uses a resin sealing gasket. It has a structure that is airtightly sealed. FIG. 1 shows the structure of the LR6 type alkaline battery 1. FIG. 1 (A) is a vertical cross-sectional view when the extension direction of the cylindrical shaft 100 is the vertical or vertical direction, and FIG. 1 (B) is an enlarged view of the inside of the circle 101 in FIG. 1 (A). The alkaline battery 1 has a so-called inside-out type structure, and is a bottomed tubular metal battery can 2, a positive electrode mixture 3 molded into an annular shape (hereinafter, also referred to as a ring core shape) similar to a ring core. A bottomed cylindrical separator 4 arranged 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 in 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, assuming that the bottom side of the battery can 2 is set downward to define the vertical direction, 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-shaped negative electrode terminal plate 7 has a dish-shaped edge with a flange-shaped edge, and is crimped to the opening of the battery can 2 via a sealing gasket 8 with the bottom surface facing up as if the dish was turned down.

The rod-shaped negative electrode current collector 6 inserted into the negative electrode gel 5 is erected and fixed by welding the upper end thereof to the lower surface 7d of the dish-shaped negative electrode terminal plate 7. The sealing gasket 8 includes a disk-shaped partition wall 81 that divides the inside of the battery can 2 into upper and lower parts, a side wall portion 82 that stands upward on the outer peripheral edge of the partition wall portion 81, and a hollow cylinder formed in the center of the partition wall portion 81. It is a resin integrally molded product having a shaped boss portion 83. The negative electrode current collector 6 is inserted into the hollow hole of the boss portion 83 of the sealing gasket 8, and when the alkaline battery 1 is assembled, the negative electrode terminal plate 7, the negative electrode current collecting 6 and the sealing gasket 8 are integrally combined as a sealing body in advance. Keep it. Then, the sealing body is inserted into the opening end side of the battery can 2 in which the power generation element is housed, and the opening of the battery can 2 is reduced in diameter inward. As a result, the side wall portion 82 of the sealing gasket 8 is sandwiched between the opening edge portion 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-shaped thin-walled portion forming a concentric circle with the boss portion 83 is formed in the region facing the negative electrode gel 5, and this thin-walled portion is the pressure inside the battery can 2. Breaks ahead of other parts of the sealing gasket 8 when it rises abnormally, and finally the gas that caused the internal pressure is released to the atmosphere through the ventilation holes 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 strongly alkaline electrolytic solution, the battery can 2 is made of nickel having a thickness of about 1.0 to 2.0 μm as shown in an enlarged manner in FIG. 1 (B). It is made of a steel plate 21 on which the (Ni) plating layer 22 is formed, and the Ni plating layer 22 is arranged at least on the inner surface side of the battery can 2. This prevents the iron constituting the steel sheet 21 from being corroded by the strongly alkaline electrolytic solution.

In Patent Document 1 below, the contact resistance between the electrode can and the positive electrode mixture is long-term by forming a coating containing cobalt (Co) in the form of a metal or compound on the inner surface side of the positive electrode can. It describes techniques for keeping it low. Further, 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. The following Non-Patent Document 1 describes a procedure for manufacturing an alkaline battery.

Special Fair 7-70320 Gazette Japanese Unexamined Patent Publication No. 2012-48958

FDK Corporation, "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 Ni-plated. However, in an alkaline battery that uses a battery can with Ni plating on the inner surface, if it is stored in a high temperature environment such as 60 ° C, which is close to the upper limit temperature of use, Ni will oxidize and the conductivity will decrease, and the discharge performance will deteriorate. There's a problem. Therefore, it is conceivable to provide a plating layer made of an alloy containing Co whose conductivity does not decrease even if it is oxidized. In the battery can described in Patent Document 2, Ni-Co is provided on the surface layer of a Ni-plated steel plate. A plating layer made of an alloy is further provided, and the thickness of the plating layer and the ratio of Co in the Ni—Co alloy are optimized.

By the way, in recent years, general-purpose batteries such as alkaline batteries have been used as power supplies for electric appliances and electronic devices such as flashlights and radios in the event of a disaster, as well as for emergency food. It has become. However, unlike emergency food, batteries cannot be consumed immediately and replaced with new stockpiles even when the expiration date is approaching. That is, when the battery expiration date is approaching, the batteries used in electric appliances and electronic devices used in daily life are not always conveniently consumed. Therefore, alkaline batteries are 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 food having a storage period of about 5 years.

Therefore, the present inventor has investigated the long-term storage performance of an alkaline battery using a battery can having a Ni-Co plating layer on the inner surface layer, which has excellent storage characteristics in a high temperature environment (hereinafter, also referred to as high temperature storage performance). As a result, it was found that when stored for an extremely long period of time, Co in the plating layer was gradually eluted in the electrolytic solution, 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 in some cases, it may lead to liquid leakage. As a matter of course, the leaked alkaline battery cannot be used as a power source for electronic devices and electric appliances.

Therefore, an object of the present invention is to provide an alkaline battery having excellent high-temperature storage performance and long-term storage performance, and a method for producing the same.

The present invention for achieving the above object is an inside-out type in which a positive electrode mixture containing a positive electrode active material and molded in a ring shape is arranged in a bottomed cylindrical battery can that also serves as a positive electrode current collector. Alkaline battery
The battery can has a plating layer made of a nickel-cobalt alloy formed on the inner surface layer of the battery can.
The positive electrode mixture contains manganese dioxide having a base potential with respect to alkali of 270 mV or more and 290 mV or less as a positive electrode active material, and a conductive auxiliary agent made of graphite is 4 wt% or more and 6 wt% or less with respect to the positive electrode active material. Included in the proportion of
It is an alkaline battery characterized by this. And it is more preferable that the graphite is expanded graphite.

The present invention also includes a method for manufacturing an alkaline battery, and the method for manufacturing the alkaline battery is described as follows.
A method for manufacturing an inside-out type alkaline battery in which a positive electrode mixture containing a positive electrode active material and formed in a ring shape is arranged in a bottomed cylindrical battery can that also serves as a positive electrode current collector.
In a bottomed cylindrical battery can that also serves as a positive electrode current collector and opens upward, the annular positive electrode mixture and a negative electrode gel arranged inside the positive electrode mixture via a separator are placed together with an alkaline electrolyte. While accommodating the battery can, the opening of the battery can is opened through the sealing gasket while the rod-shaped negative electrode collector connected to the lower surface of the disk-shaped negative electrode terminal plate is inserted into the negative electrode gel in a vertically vertical direction. Including an assembly step of assembling the alkaline battery by sealing with the negative electrode terminal plate and an aging step of leaving the assembled alkaline battery 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 or more and 290 mV or less is used as a positive electrode active material, and a conductive auxiliary agent made of graphite is used. 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.
This is a method for manufacturing alkaline batteries.

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

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 Example of this invention.

Examples of the present invention will be described below with reference to the accompanying drawings. In the drawings used in the following description, the same or similar parts may be designated by the same reference numerals and duplicate description may be omitted. A coded part in one drawing may not be coded in another drawing if it is not necessary.

=== Technical idea in the embodiment of the present invention ===
As described above, in an alkaline battery using a battery can in which a Ni-plated layer is formed on the inner surface layer, Ni is oxidized and the conductivity of the battery can is lowered 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 lowered even if the inner surface of the battery can is oxidized. do not. However, even an alkaline battery using a battery can on which a Ni—Co plating layer is formed may leak liquid if stored for an extremely long period of time such as 10 years or more.

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

=== Examples of the present invention ===
FIG. 2 shows the structure of the alkaline battery 1a according to the embodiment of the present invention. FIG. 2A is a vertical cross-sectional view of the alkaline battery 1a, and FIG. 2B is an enlarged view of the inside of the circle 102 in FIG. 2A. 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 this embodiment, a Ni—Co plated layer is formed on the inner surface of the battery can 2a. 23 is formed, and as shown in FIG. 2B, the metal material constituting the battery can 2a uses the steel plate 21 on which the Ni plating layer 22 is formed as a base material, and Ni on the surface layer of the base material. The −Co plating layer 23 is formed. A Ni plating layer 22 and a Ni—Co plating layer 23 are formed on the inner surface side of the battery can 2a at least.

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

== Sample ===
In order to evaluate the high-temperature storage performance and the 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 provided with a battery can 2 made of a steel plate 21 having only a Ni-plated layer 22 formed on the surface layer was also produced as a sample. The battery can (2, 2a) is basically a sample in which a steel plate 21 having a thickness of about 0.15 mm is used as a base material and a Ni plating layer 22 having a thickness of, for example, about 1.5 μm is formed. Therefore, a Ni—Co plating layer 23 having a thickness of about 0.2 μm is formed on the surface layer of the Ni plating layer 22.

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

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

For the high temperature storage test, changes in discharge performance before and after the test were investigated. Specifically, one cycle is a discharge operation in which each sample is discharged at a power consumption of 1.5 W for 2 seconds and then discharged at a power consumption of 650 mW for 28 seconds, and 10 cycles (5 minutes) are continuously performed for 1 hour. A pulse discharge test was conducted in which the battery was discharged, paused for 55 minutes, and then discharged again for 10 cycles in the next 1 hour. Then, the number of cycles until the final voltage of 1.05 V was reached was measured. A long-term storage test in which samples are stored at 80 ° C. for 4 months is equivalent to storage at room temperature for 13 years. After the long-term storage test, each sample is visually checked for leakage and belongs to each sample. The number of individuals in which leakage occurred was counted among the 10 individuals.

Table 1 below shows the preparation conditions for 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 the samples shown in FIG. The battery can 2a in which the Ni—Co plating layer 23 is formed on the inner surface of the Ni plating layer 22 shown in the above is used. Further, the types of graphite used as the conductive auxiliary agent are different between Samples 1 to 15 and Samples 16 to 22, and Samples 1 to 15 use artificial graphite having a particle size of about 15 μm, which is generally used as the conductive auxiliary agent. Samples 16 to 22 use expanded graphite having a large aspect ratio and a major axis extending to about 40 μm.

Further, "annealing" in the table means that the steel plate material used for the battery cans (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 cans (2, 2a) are usually made of an annealed steel plate material. Here, except for the samples 21 and 22, a battery can (2, 2a) made of an annealed steel plate material was used.

From Table 1, first, in the samples 1 to 5 using the battery can 2 having only the Ni plating layer 22 on the inner surface, the larger the alkali base potential of EMD (“EMD potential” in the table), the more the discharge in the initial state. 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 significantly deteriorated. On the other hand, in the samples 6 to 22 using the battery can 2a having the Ni—Co plating layer 23 on the inner surface layer, the discharge characteristics of at least 50% or more were maintained before and after the high temperature storage test. Then, from samples 6 to 10 in which the type and amount of graphite added but only the alkali base potential is different, if the alkali base potential is 270 mV or more and 290 mV or less, the discharge performance of 80% or more of the initial state can be obtained even after the high temperature storage test. Turned out to keep. 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, as compared with those before the test. In the other samples 6 to 8, the discharge performance after the test was 80% or more with respect to the initial state. Therefore, the samples 9 and 10 in which the EMD having an alkali base potential of 260 mV or less was used as the positive electrode mixture were relatively relative. It was found that the high temperature storage performance was inferior. In addition, in Samples 9 and 10, there were individuals in which liquid leakage occurred after the long-term storage test. Based on the above, the alkaline battery 1a of the present embodiment uses a battery can 2a having a Ni—Co plated layer formed on the inner surface layer, and the alkali base potential of EMD contained in the positive electrode mixture 3 as the positive electrode active material is 270 mV. The condition is that the voltage is 290 mV or less.

Next, in the samples 11 to 15, the alkali base potential is set to 280 mV, and artificial graphite is used as the conductive auxiliary agent. And the amount of artificial graphite added is different. The amount of artificial graphite added is a mass ratio to EMD. In Samples 11 to 15, the discharge performance after the high temperature storage test was 50% or less as compared with that before the test in Sample 15 in which the amount of artificial graphite added was 3 wt%. In addition, in the samples 11 and 12 in which the addition amount was 8 wt% or more, there were individuals in which liquid leakage occurred after the long-term storage test. From the above, it is desirable that the amount of graphite added as a conductive auxiliary agent is 4 wt% or more and 6 wt% or less. Based on 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 embodiment of the present invention has a battery can 2a having a Ni—Co graphite 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 as a conductive auxiliary agent is added at a ratio of 4 wt% or more and 6 wt% or more to the positive electrode active material is provided. Become. According to the alkaline battery 1a of the present embodiment, the discharge characteristics are maintained before and after high-temperature storage, no liquid leakage occurs even after storage for an extremely long period of time, and excellent high-temperature storage performance and long-term storage performance are provided.

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

Here, considering the reason why the samples 6 to 8, 13, 14, 18, 19, 21, and 22 showed excellent high-temperature storage performance and long-term storage performance, first, regarding the long-term storage performance, the alkali-based potential of EMD. It can be considered that the high temperature storage performance was exhibited because Co was more easily oxidized, thereby promoting the oxidation of Co and making it difficult for Co to elute. Further, in these samples, the amount of graphite added, which has water repellency and low affinity with the alkaline electrolyte, is optimized, so that the oxidation of Co is not inhibited and the discharge is performed before and after the high temperature storage test. It can be considered that the performance is maintained.

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

Here, an alkaline battery 1a prepared under the same conditions as the samples 7 and 18 in Table 1 and an alkaline battery 1a subjected to an aging treatment in which the samples 7 and 18 were stored at a temperature of 45 ° C. for 24 hours were prepared as samples. .. In addition, for each sample, 10 individuals to be subjected to each of the high temperature storage test and the long-term storage test were prepared. Then, the high-temperature storage performance and long-term storage performance with and without aging treatment were investigated. Since the prepared samples are expected to have excellent long-term storage performance similar to samples 7 and 18, if no liquid leakage occurs after the test, the sample after the test is placed in water. The gas in the battery can was collected by water replacement and the amount of the gas was measured.

Table 2 below shows the effects 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 Samples 7 and 18 in Table 1, respectively. Samples 25 and 26 are alkaline batteries 1a obtained by aging the alkaline batteries 1a produced under the same conditions as the samples 23 and 24. As shown in Table 2, the high temperature storage performance was reduced by about 1.5% due to 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 leaked after the test. However, it was found that the amount of gas generated after the long-term storage test was reduced by about 30% to 35% by performing the aging treatment. That is, it was confirmed that the long-term storage performance was further improved by the aging treatment.

Regarding the aging treatment, the higher the temperature and the longer the time, the more the oxidation of Co in the Ni—Co plating layer in the battery can is promoted. However, on the other hand, the high temperature storage performance may deteriorate. Therefore, the temperature and time in the aging treatment may be appropriately set according to the target high temperature storage performance.

1,1a alkaline battery, 2,2a battery can, 3 positive electrode mixture, 4 separator,
5 Negative electrode gel, 6 Negative electrode current collector, 7 Negative electrode terminal plate, 8 Seal gasket,
9 Positive electrode 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 containing a positive electrode active material and molded in a ring shape is arranged in a bottomed cylindrical battery can that also serves as a positive electrode current collector.
The battery can has a plating layer made of a nickel-cobalt alloy formed on the inner surface layer of the battery can.
The positive electrode mixture contains manganese dioxide having an alkali base potential of 270 mV or more and 290 mV or less as the positive electrode active material, and the conductive auxiliary agent made of graphite is 4 wt% or more and 6 wt% or less with respect to the positive electrode active material. Included in proportion,
Alkaline battery that is characterized by that. The alkaline battery according to claim 1, wherein the graphite is expanded graphite. A method for manufacturing an inside-out type alkaline battery in which a positive electrode mixture containing a positive electrode active material and formed in a ring shape is arranged in a bottomed cylindrical battery can that also serves as a positive electrode current collector.
In a bottomed cylindrical battery can that also serves as a positive electrode current collector and opens upward, the annular positive electrode mixture and a negative electrode gel arranged inside the positive electrode mixture via a separator are placed together with an alkaline electrolyte. While accommodating the battery can, the opening of the battery can is opened through the sealing gasket while the rod-shaped negative electrode collector connected to the lower surface of the disk-shaped negative electrode terminal plate is inserted into the negative electrode gel in a vertically vertical direction. Including an assembly step of assembling the alkaline battery by sealing with the negative electrode terminal plate and an aging step of leaving the assembled alkaline battery 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 or more and 290 mV or less is used as a positive electrode active material, and a conductive auxiliary agent made of graphite is used. 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.
A method for manufacturing an alkaline battery.

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