JP2001345080A - Ni-plated steel sheet for alkaline manganese battery positive electrode can, method for producing the same, and positive electrode can using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Ni-plated steel sheet for a positive electrode can having a surface serving as an inner surface of a can that provides good battery characteristics in an alkaline manganese battery, a method for producing the same, and a positive electrode can using the same. SOLUTION: The adhered amount on the surface to be the inner surface of the can is 1 as Ni.
拡 散 9 g / m ² of Fe—Ni diffusion layer.
A Ni-plated steel sheet having many crack-like depressions on the surface of the i-diffusion layer. This Ni-plated steel sheet is formed by subjecting one side of the steel sheet to Ni plating of 1 to 9 g / m ² and then performing a heat treatment to form an Fe—Ni diffusion layer having a number of depressions on cracks on the surface. Can be manufactured. The Ni-plated steel sheet having such a surface retains its crack-shaped dents even after press working, or is partially stretched and expanded, so that a positive electrode can having a high potential of battery characteristics can be obtained. The surface serving as the outer surface of the positive electrode can has an N of 12 g / m ² or more.
It is desirable that a portion of this Ni has an Fe-Ni diffusion layer in order to impart good corrosion resistance to the outer surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Ni-plated steel sheet material used for a positive electrode can of an alkaline manganese battery and a method for producing the same, and further relates to a positive electrode can formed using the Ni-plated steel sheet. The present invention relates to a plated steel sheet material capable of improving heavy load discharge characteristics and corrosion resistance of a battery, a method for producing the same, and a positive electrode can formed using the same.

[0002]

2. Description of the Related Art In general, in an alkaline manganese battery, a Ni-plated steel plate is used as a material for a container (positive electrode can) which is filled with a positive electrode material, a negative electrode material, an electrolytic solution, etc. and also serves as a positive electrode terminal. Is done. Conventionally, Ni plating has been performed by so-called barrel plating after processing into a can. However, since the adhesion of Ni plating to the inner surface of the can is insufficient and there is a problem of instability in quality, a pre-plated steel plate is used for the can. The method of processing into the mainstream has become mainstream.

[0003] In the case of a pre-plated steel sheet, the Ni plating layer is hard and has poor spreadability, so that there is a problem that press workability is inferior, and that the plating is peeled off during processing and the corrosion resistance is likely to deteriorate. As a method of solving this problem, a heat treatment is performed after Ni plating to form an Fe—Ni diffusion layer at the interface between the plating and the base iron, thereby improving the adhesion. At the same time, Ni is recrystallized and softened to form a plated layer. A method for improving the spreadability is known, and the press workability and the corrosion resistance are greatly improved.

[0004] However, it is known that such a steel sheet having good press workability and corrosion resistance is inferior in heavy load discharge characteristics of a battery, particularly, characteristics after storage.
It is a major technical problem to provide a steel sheet that achieves both corrosion resistance and battery characteristics.

Regarding the heavy-load discharge characteristics of the above-mentioned battery,
This is one of the most important characteristics for an alkaline manganese battery because the use of heavy loads has increased in recent years mainly in AV equipment. Nevertheless, the effect of the steel plate for positive electrode cans on the heavy load discharge characteristics has not been sufficiently clarified, and there are only a few prior arts described below for steel plates that can improve the characteristics. .

In JP-A-5-21044, as a material for DI drawing, it is effective to apply hard plating that causes cracks in the Ni plating layer during processing. The resulting cracks in the plating layer are caused by the positive electrode material (including conductive paint mainly composed of carbon applied to the inner surface of the battery can. Hereinafter, the expression “positive electrode material” in this specification includes the conductive paint). It is said that the contact area is increased, and the battery characteristics are also improved. As the hard plating, Ni plating containing an organic additive or Fe-
Various examples are given, such as those plated with a Ni diffusion layer.

JP-A-7-122246, JP-A-7-122246
In JP-A-300695 and WO95 / 11527, a very hard Ni—Sn alloy plating layer (for example, Ni ₃ Sn, Ni ₃ S) is formed on the outermost surface of the surface corresponding to the inner surface of the positive electrode can.
It is disclosed that by forming n ₂ , Ni ₃ Sn _4, etc.), a crack is formed in the plating layer during press working to ensure contact with the positive electrode material.

In Japanese Patent Application Laid-Open No. Hei 8-138636, a steel plate is double-plated with Sn and Ni in this order.
Furthermore, by bringing the plating layer alloyed by heat treatment to the inner surface of the positive electrode can, cracks occur on the surface due to the difference in elongation between the upper plating layer mainly composed of Ni and the lower plating layer containing Sn during press working, It is disclosed that this increases the contact area with the positive electrode material and improves battery characteristics.

In Japanese Patent Application Laid-Open No. 9-306439, a Ni alloy plating having a different plating hardness is applied so that the hardness of the surface to be the inner surface of the can is increased, and the roughness of the inner surface of the can is reduced during press working. It is disclosed to increase the adhesion to improve the adhesion to the cathode material. As a method of giving a difference in hardness by alloy plating, it is exemplified that the type and amount of an alloy metal with Ni and the amount of an organic additive are made different.

[0010] JP-A-10-172521 and JP-A-10-152522 disclose that a surface serving as an inner surface of a positive electrode can is plated with Ni-Co alloy or Ni-Co alloy plating through Ni plating. Have been. N
It is stated that since the i-Co alloy plating is very hard, very fine cracks are generated at the time of press working, very fine irregularities are formed, contact with the positive electrode material is improved, and performance can be improved.

In Japanese Patent Application Laid-Open No. 11-102671, Japanese Patent Application Laid-Open No. H11-102671 discloses a method in which Ni-plating
It is disclosed to apply Ag alloy plating or Ni-Cr alloy plating. Ni-Ag alloy plating, Ni-Cr
It is said that since the alloy plating is very hard, very fine cracks are generated at the time of press working, very fine irregularities are formed, contact with the positive electrode material is improved, and performance can be improved.

In Japanese Patent Application Laid-Open Nos. 11-329377 and 11-329378, Ni-Fe and Ni-Fe alloys are used for the purpose of further improving the battery performance by improving the alkali resistance, which is a weak point of the Ni-Sn-based alloy plating. The use of Bi alloy plating and Ni-In alloy plating is disclosed.

[0013]

A consistent idea for improving the battery characteristics by using a steel sheet material in the prior art is to form minute irregularities on the inner surface of the can by press working. As the steel plate, a steel plate which has been subjected to hard plating such that a crack occurs in a plating layer during press working is mainly employed.

However, the idea of forming a crack in the plating layer during such press working has the following problems. (1) The cracking condition of the plating layer varies due to the variation in the press working conditions, and it is difficult to obtain stable battery characteristics. (2) Those employing hard plating are likely to lead to deterioration of pressability and corrosion resistance due to peeling of plating. for example,
Even when the base of hard plating is subjected to ordinary Ni plating or the like, the plating cracking or peeling of the upper layer easily spreads to the lower layer and cannot be a complete solution. In addition, the use of multi-layer plating leads to an increase in material cost. (3) The use of alloy plating as a means for obtaining hard plating causes an increase in material cost.

Accordingly, the present invention provides a Ni-plated steel sheet material for a positive electrode can having a surface that becomes an inner surface of the can that provides good battery characteristics in an alkaline manganese battery, a method of manufacturing the same, and a Ni plating. The object of the present invention is to provide an alkaline manganese battery positive electrode can using a steel plate material.

Further, the present invention provides a Ni-plated steel sheet material for use in a positive electrode can of an alkaline manganese battery, which has good corrosion resistance on the outer surface of the can and is advantageous in terms of manufacturing cost, a method for producing the same, and a Ni-plated steel sheet material. The object of the present invention is to provide a positive electrode can of an alkaline manganese battery.

[0017]

According to the present invention, the surface condition of the inner surface of the positive electrode can, which maintains the contact area with the positive electrode material and contributes to the improvement of battery characteristics, is not formed at the time of press working, but is originally formed on the material surface. It is intended to be provided and to prevent it from being lost during press working.

That is, the Ni-plated steel sheet for an alkaline manganese battery positive electrode can of the present invention has an adhesion amount of N
It is characterized by having an Fe—Ni diffusion layer of 1 to 9 g / m ² as i, and having many crack-shaped depressions on the surface of the Fe—Ni diffusion layer.

The method according to the present invention for producing the above-mentioned Ni-plated steel sheet comprises the steps of: 1 to 9 g / m ^{2 on} one side of the steel sheet;
After applying Ni plating, a heat treatment is performed to form an Fe—Ni diffusion layer having a large number of depressions on cracks on the surface.

The Ni-plated steel sheet having such a surface retains its crack-shaped dents even after press working, or is partially stretched and expanded, so that a positive electrode can having a high potential of battery characteristics can be obtained. can get.

Further, the above-mentioned Ni-plated steel according to the present invention
The surface of the plate that becomes the outer surface of the can is 12 g / m ^TwoWith above Ni
Then, a part of this Ni forms a Fe—Ni diffusion layer.
It is desirable. The surface that will become the outer surface of the Ni-plated steel can
To provide good corrosion resistance by
Can be.

The method according to the present invention for producing a Ni-plated steel sheet having such a can outer surface and the above-described can inner surface has the following effects.
It is characterized in that an Fe—Ni diffusion layer is formed by applying a heat treatment after applying Ni plating of 12 g / m ² or more to the other surface of m ² and the other surface. According to this method, a Ni-plated steel sheet having predetermined inner and outer surfaces can be manufactured by one Ni plating and one heat treatment, which is advantageous in terms of manufacturing cost.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the structure of a surface corresponding to the inner surface of a positive electrode can of an alkaline manganese battery according to the present invention will be described. On the surface to be the inner surface, the adhesion amount is 1 to 9 g as Ni.
/ M ² It is necessary to have a Fe-Ni diffusion layer and to have many crack-like dents on the surface. It is presumed that in this state, the adhesion between the inner surface layer of the can and the cathode material after the cathode can has been enhanced, and the battery characteristics are improved.

Here, the crack-shaped dent means a pit that is observed as a diagonal diagonal with a long side of about 1 μm and a short side of 1 μm or less when the surface of the plated steel sheet is observed by SEM. An actual example is shown in FIGS. For these, the inner surface of the sample of the Ni-plated steel sheet manufactured in Example 2 described later was subjected to SEM (acceleration voltage 15 kV,
(Magnification 1000 times and 5000 times). In addition, as an example, although not having the crack-like dents and having inferior battery characteristics, the outer surface (Ni adhesion amount: 18 g / m ² ) of the Ni-plated steel sheet sample similarly manufactured in Example 2 described later was used. The results of SEM observation are shown in FIGS.

Next, the structure of the outer surface of the positive electrode can of the alkaline manganese battery according to the present invention will be described. The outer surface has Ni of 12 g / m ² or more, and a part of this Ni is an Fe—Ni diffusion layer. Is formed, which improves the corrosion resistance of the positive electrode terminal portion which is subjected to particularly severe processing.

The conditions for producing the Ni-plated steel sheet having the crack-like depressions will be described below for each step.

<Plated Steel Sheet> The coated steel sheet is not particularly limited as long as it can be plated with Ni. Considering that the steel sheet is provided for processing for a battery case, the extremely low carbon steel is made of Ti or Nb. Etc. alone or in combination,
Low-carbon Al-killed steel, B-added low-carbon steel and the like are preferable. In addition, even an unrecrystallized steel sheet after cold rolling, a steel sheet after recrystallization annealing or a steel sheet after temper rolling can be used, but in the present invention, a heat diffusion treatment is required after Ni plating. From the economic viewpoint, it is preferable to simultaneously perform recrystallization annealing of the base steel sheet during the thermal diffusion treatment. From this viewpoint, the most advantageous embodiment in the present invention uses an unrecrystallized steel sheet after cold rolling as the base steel sheet.

<Plating Pretreatment> There is no limitation as long as it is a pretreatment for applying Ni plating, and ordinary processing such as degreasing and pickling, which has been conventionally used, may be performed.

<Ni Plating> Ni plating differs between the inner surface and the outer surface. First, the Ni plating on the inner surface will be described. It is necessary to perform a matte Ni plating with an adhesion amount of 1 to 9 g / m ² as Ni. It is difficult to form. In addition, if it is less than the lower limit, the battery performance is likely to deteriorate due to the reaction due to the alkaline solution which is the battery electrolyte.Furthermore, rust occurs when the press oil is degreased and left for a while after being processed into a positive electrode can. The problem that it is easy to do. On the other hand, if the upper limit is exceeded, the surface layer tends to be smoothed when processed into a positive electrode can, and the battery performance tends to deteriorate.

As for the outer surface, Ni was 12 g / m ^2.
It is desirable to perform Ni plating with an adhesion amount of. If the Ni adhesion amount is less than this, corrosion resistance is insufficient and product performance as a battery is undesirably deteriorated. Although there is no particular upper limit, it is up to about 50 g / m ² from an economic viewpoint.

The inner surface and the outer surface are most preferably economically manufactured by a single plating process using the same plating bath to make the respective amounts of adhesion by giving a difference in the amount of current applied to each surface. It is of course possible to plate separately in different plating baths. The type of the plating bath is not particularly limited, and a watt bath, a sulfamic acid bath, a chloride bath, a sulfuric acid bath, or the like is used, and a watt bath is preferable in consideration of workability. In the present invention, instead of pure Ni plating, inevitable impurities, for example, Fe-containing plating may be used. In particular, when Ni plating is performed in a low-pH sulfuric acid bath, the Fe ion concentration in the plating bath increases, Fe on Ni plating layer
Is eutectoid, but there is no problem as long as the above-mentioned adhesion amount is secured as Ni. Further, it is not preferable to add a gloss additive to the plating bath because S, C, etc., which are eutectoid in the plating layer under the influence of the gloss additive, are likely to have an adverse effect in the subsequent heat diffusion treatment step. It is desirable not to use not only the gloss additive but also an organic additive called a leveling agent or a pinhole inhibitor.

<Thermal Diffusion Treatment> A heat treatment is performed in an atmosphere of an inert gas or a reducing gas to form a Fe—Ni diffusion layer. At this time, from the viewpoint of battery performance, it is indispensable for the inner surface that Fe diffuses to the surface layer and the plated Ni exists as a Fe—Ni diffusion layer. During the heat treatment, the stress contained during the plating is released, and the recrystallization, and further, the alloying with Fe proceeds, the surface shape changes, and a crack-like dent is formed.

On the other hand, it is preferable that Fe does not diffuse to the surface layer on the outer surface and Ni remains on the surface layer via the Fe-Ni diffusion layer.

The difference in the diffusion state between the inner surface and the outer surface as described above can be achieved by adjusting the amount of Ni plating to an appropriate value on the inner surface and the outer surface as described above and adjusting the temperature and time of the heat treatment. It is possible. Specifically, the heat treatment conditions are about 650 ° C. to 820 ° C. and 10 to 1
It is desirable to perform the process for about 20 seconds, and it is necessary to set the time condition to an appropriate time depending on the amount of Ni attached. Whether the state of surface diffusion after heat treatment is appropriate is determined by surface analysis such as GDS (glow discharge spectroscopy), ESCA, and AES.
It can be confirmed whether or not e is diffused to the surface layer.

When an unrecrystallized steel sheet is used as the base steel sheet, the thermal diffusion treatment and the recrystallization annealing of the steel sheet can be performed simultaneously by setting the heat treatment here to a temperature higher than the recrystallization temperature of the steel sheet. .

<Temperature Rolling> Although not necessarily required, the outer surface is often seen by the battery consumer, so that a glossy appearance is often required. In such a case, a roll having a surface roughness RA of about 0.07 μm or less is used for the outer surface, and rolling is performed so that the elongation is about 1 to 3%. At this time, as described above, 12 g /
has m ² or more Ni, a part of the Ni may form an Fe-Ni diffusion layer, if the state of the surface layer is left Ni, good gloss appearance gloss of 700 or more by rolling Easy to get.

[0037]

The present invention will be described in detail with reference to the following examples. [Examples 1 to 5] Nb and Ti-added ultra-low carbon steel (unrecrystallized steel plate) having a thickness of 0.3 mm was used as a base plate, and Ni plating was performed after degreasing and pickling. The degreasing condition was caustic soda 5
0 g / L (liter), at a bath temperature of 60 ° C., anodizing (20 A / dm ² ) × 5 seconds and cathodic processing (20 A / dm ² )
/ Dm ² ) × 5 seconds. The pickling condition is sulfuric acid 50g /
L, immersed at room temperature for 10 seconds.

As the Ni plating bath, the following watt bath without additives was used, and plating was performed on both sides at a current density of 50 A / dm ^{2 in} a vertical circulation cell. Nickel sulfate: 350 g / L Nickel chloride: 70 g / L Boric acid: 45 g / L pH: 4.2

The amount of Ni plating was determined according to Examples 1 to 3 in Table 1.
As shown in FIG. 5, Ni plating with a different thickness was applied to each of the inner surface and the outer surface. After the Ni plating, a heat diffusion treatment at 790 ° C. × 20 seconds was performed in a nitrogen atmosphere. Further, the surface roughness was adjusted by temper rolling to give a glossy appearance.

When GDS analysis was performed after the above treatment, the inner surface was found to have a Fe-Ni diffusion layer in which Fe was diffused to the outermost layer in all of Examples 1 to 5. Regarding the surface to be the outer surface, in Examples 1 to 5, the Fe—Ni diffusion layer was only the interface with the ground iron and the outermost layer was Ni plating.

[Comparative Examples 1 to 4] In the same manner as in the example, Ni plating was applied to the inner surface and the outer surface, respectively, with the adhesion amounts shown in Table 1, and then heat diffusion treatment was performed. . However, in Comparative Example 1, a recrystallized and annealed steel sheet was used as an original sheet, and no heat diffusion treatment was performed after Ni plating.

With respect to the Ni-plated steel sheet samples prepared in Examples 1 to 5 and Comparative Examples 1 to 4, the inner surface condition was observed by the following method, and the inner surface performance and the outer surface performance were evaluated. The results are shown in Table 1.

<Inner Surface Condition> The inner surface was observed by SEM (acceleration voltage: 15 KV, magnification: 5,000). <Inner surface performance evaluation method> Battery characteristics after storage: A normal LR14 type alkaline manganese battery was manufactured using a positive electrode can obtained by pressing a steel plate sample, and after storage at 60 ° C for 20 days, the following battery characteristics were measured. The internal resistance was measured at 20 ° C. with an AC impedance of 1 kHz. The short-circuit current was measured at 20 ° C. with a no-load ammeter. Regarding the discharge characteristics, a continuous discharge of 1 A was performed at 20 ° C., and the discharge time was measured with 0.9 V as the end point voltage. Corrosion resistance (primary rust prevention): After degreasing the positive electrode can obtained by pressing a steel plate sample, sealing the end face with beeswax, and then heating at 60 ° C × 90.
It was left for 3 days in a% RH atmosphere. Thereafter, the inner surface was finely observed with a loupe (magnification: 10 times) to observe the occurrence of rust. No rust was indicated by “〇”, and rust was indicated by “×”.

<Outer surface performance evaluation method> Corrosion resistance: After degreasing the positive electrode can formed by pressing a steel plate sample, sealing the end face with beeswax, spraying salt water (JIS-Z-2371) with the positive electrode convex terminal outer surface facing upward. Conforms to the test machine. After performing the test for 3 hours, the sample was taken out, washed with water and dried, and the occurrence of red rust was observed. No rust was indicated by “〇”, and rust was indicated by “×”.

[0045]

[Table 1]

[0046]

As can be seen from the above detailed description, it is clear that a predetermined amount of Ni is deposited on the inner surface of the can.
The Ni-plated steel sheet for an alkaline manganese battery positive electrode can of the present invention having a Ni diffusion layer and having many crack-shaped depressions can provide good battery characteristics and corrosion resistance.

Further, by providing a predetermined amount of Ni adhesion on the surface to be the outer surface of the can and forming an Fe—Ni diffusion layer on a part of the Ni, it is possible to provide good corrosion resistance to the outer surface of the can.

[Brief description of the drawings]

FIG. 1 is a SEM photograph (1000 × magnification) of the surface of a Ni-plated steel sheet having a crack-like dent according to the present invention.

FIG. 2 is an SEM photograph (5000-fold magnification) of the surface of a Ni-plated steel sheet having a crack-like dent according to the present invention.

FIG. 3 is an SEM photograph (magnification: 1000 ×) of the surface of a Ni-plated steel sheet having no crack-like dents.

FIG. 4 is an SEM photograph (magnification: 5,000) of the surface of a Ni-plated steel sheet having no crack-like dents.

FIG. 5 shows the S of the inner surface of the Ni-plated steel sheet of Example 1.
EM photograph (magnification 5000 times).

FIG. 6 shows the S of the inner surface of the Ni-plated steel sheet of Example 3.
EM photograph (magnification 5000 times).

FIG. 7 shows S of the inner surface of the Ni-plated steel sheet of Comparative Example 1.
EM photograph (magnification 5000 times).

FIG. 8 shows S of the inner surface of the Ni-plated steel sheet of Comparative Example 2.
EM photograph (magnification 5000 times).

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Teruaki Yamada 1-Fuji-cho, Hirohata-ku, Himeji-shi, Hyogo Nippon Steel Corporation Hirohata Works (72) Inventor Tomohiro Mino Fuji-cho, Hirohata-ku, Himeji-shi, Hyogo 1 Nippon Steel Corporation Hirohata Works (72) Inventor Tokuhisa Watanabe 5-36-11 Shimbashi, Minato-ku, Tokyo Inside Fuji Electric Chemical Co., Ltd. (72) Inventor Kiyohide Tsutsui 5 Shimbashi, Minato-ku, Tokyo No.36-11, Fuji Electric Chemical Co., Ltd. (72) Inventor Hirohiko Ota 5-36-11, Shimbashi, Minato-ku, Tokyo F-term within Fuji Electric Chemical Co., Ltd. 4K024 AA03 AB01 AB06 BA03 BB09 BB21 BC01 DB01 DB07 GA04 GA16 5H011 AA03 CC06 DD00 DD03 DD09 DD10 DD18 FF02 GG02 KK00 5H024 AA03 AA14 BB01 BB05 CC02 CC06 CC07 CC08 CC14 CC19 DD02 EE01 HH00 HH15

Claims (7)

[Claims] 1. The amount of adhesion to the inner surface of the can is 1 as Ni.
拡 散 9 g / m ² of Fe—Ni diffusion layer.
A Ni-plated steel sheet for an alkaline manganese battery positive electrode can, characterized in that the surface of the i-diffusion layer has many crack-shaped depressions. 2. The method according to claim 1, wherein the outer surface of the can has Ni of 12 g / m ² or more, and a part of the Ni forms an Fe—Ni diffusion layer. Ni-plated steel plate for alkaline manganese battery positive electrode cans. 3. A steel sheet, wherein one side of the steel sheet has 1-9 g / m ² of Ni.
2. The Ni-plated steel sheet for an alkaline manganese battery positive electrode can according to claim 1, wherein a heat treatment is performed after plating to form an Fe-Ni diffusion layer having a large number of depressions on cracks on the surface. Method. 4. A method of forming an Fe—Ni diffusion layer by subjecting one side of a steel sheet to Ni plating of 1 to 9 g / m ² and the other side of 12 g / m ² or more, followed by heat treatment. The method for producing a Ni-plated steel sheet for a positive electrode can of an alkaline manganese battery according to claim 2. 5. The positive electrode can for an alkaline manganese battery according to claim 3, wherein the Ni plating is performed using a plating bath composed of nickel sulfate, nickel chloride, boric acid, and unavoidable impurities. Manufacturing method of Ni-plated steel sheet. 6. The surface roughness is adjusted by rolling after the heat treatment.
5. The method for producing a Ni-plated steel sheet for a positive electrode can of an alkaline manganese battery according to item 4. 7. An alkaline manganese battery positive electrode can obtained by deep drawing the Ni-plated steel sheet according to claim 1 or 2.