JP2002060899A - Steel plate for forming battery can, battery can, manufacturing method of battery can and battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the battery performance by increasing the surface roughness of an inner surface of a battery can in the axial direction of the can. SOLUTION: A steel plate for forming the bottomed cylindrical battery can by pressing contains coarse grains of the grain size of >=30 μm, the volumetric ratio of the coarse grains is >=5%, and the mean grain size is <=150 μm. A layer consisting mainly of coarse grains with mean grain size of 30 μm to 150 μm is provided on at least one surface layer part of the steel plate, and portions other than the layer consists of grains of the grain size of <30 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel sheet for forming a battery can, a method for manufacturing a battery can using the steel sheet for forming a battery can, a battery can manufactured by the method, and a battery provided with the battery can. Particularly, a rough surface is provided on the inner surface of the battery can to increase the holding power of the filling material.

[0002]

2. Description of the Related Art Conventionally, as a method for manufacturing a battery can having a bottomed cylindrical shape, a steel plate having a plating layer on its surface is formed, or a steel plate is formed into a battery can and then plated (so-called galvanization). There are times when you do. As a processing method of forming the above-mentioned steel plate or plated steel plate into a battery can having a cylindrical shape with a bottom, a so-called transfer process (multi-stage drawing and ironing process) combining multi-stage drawing, multi-stage drawing and ironing, DI (draw)
Various pressing methods are used, such as drawing and ironing, stretch draw, or a combination of stretch draw and ironing.

[0003]

The inner surface of the battery can formed by the above-described processing increases the smoothness due to the processing and reduces the contact area with the active material filled in the battery can, thereby improving the battery performance. Is difficult. Specifically, primary batteries have a problem that the holding power of the positive electrode active material filled in the battery can is weak.Also, the inner surface of the battery can is usually coated with carbon powder. The powder tends to fall off to the bottom, thus reducing the contact area between the active material and the carbon powder. In a secondary battery, the electrode plate is spirally wound and filled into the battery can. If the outer peripheral surface of the electrode plate is not parallel to the inner peripheral surface of the can, the inner peripheral surface of the can that is a smooth surface is There is a problem that the contact area with the plate is reduced and the electrode plate cannot be stably held.

To solve the above problem, Japanese Patent Laid-Open No. 60-18 / 1990
No. 0058 discloses a method for manufacturing a battery can in which a longitudinal groove parallel to the axis is drawn using a punch having a circumferential surface on a peripheral surface to form a vertical groove in the inner surface of the battery can in the axial direction of the can. Also, the applicant of the present application has previously disclosed in Japanese Patent No. 280257 a battery in which a surface serving as an inner surface of a battery can is formed of a hard plating layer and a large number of wedges are formed in vertical and horizontal oblique directions during drawing.

However, since the carbon powder applied to the inner surface of the battery can easily falls off in the axial direction of the can when filling the contents, the carbon powder described in Japanese Patent Application Laid-Open No. 60-180058 has a vertical surface in the axial direction of the can. The method of providing the groove hardly contributes to the enhancement of the holding power of the carbon powder and does not contribute to the holding of the contents filled in the battery can, so that the effect of improving the battery performance is very small. Patent No. 281025
The technology described in No. 7 achieves an improvement in the holding power of the carbon powder and an increase in the contact area, and is effective in improving the battery performance.
The demand for improved battery performance is increasing year by year, and further improvement is desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has an excellent carbon powder holding force and an increased contact area with a filling content when formed into a battery can. It is an object of the present invention to provide a battery can-forming steel sheet, a battery can, a method for manufacturing a battery can, and a battery which can significantly improve performance.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have made intensive studies and as a result, have coarse grains of a specific size, thereby suppressing the smoothing of the inner surface of the can by processing. It has been found that it is possible to impart appropriate roughness to improve battery performance.

[0008] Based on the above results, the present invention firstly comprises coarse crystal grains having a particle size of 30 µm or more, wherein the volume fraction of the coarse crystal grains is 5% or more, and The present invention provides a steel sheet for forming a battery can, wherein the average crystal grain size of the crystal grains is 150 μm or less.

Conventionally, it is a conventional theory that the crystal grain size of a steel sheet for forming a battery can is desirably uniform and fine, and a steel sheet having an average grain size of several μm to about 20 μm is generally used. When the crystal grains are coarse, the strength of the steel sheet is reduced, and non-uniform deformation occurs at the time of forming the battery can, so-called "skin roughness" is caused, the workability is deteriorated and the can is easily broken. However, according to the research results of the present inventor, by having an appropriate amount of coarse crystal grains larger than the crystal grains of the conventional steel sheet, sufficient workability is maintained and can body breakage is suppressed, and the processed can It has been found that the inner surface roughness can be increased, and the holding power of the carbon powder and the active material can be enhanced.

In order to obtain this effect, it is necessary to contain crystal grains having a particle size of 30 μm or more in a volume ratio of 5% or more as described above. On the other hand, in order to secure the minimum strength and workability necessary for forming the battery can, the average crystal grain size is 150 μm.
It is desirable that: Average grain size is 150μm
If it exceeds, it may be broken at the time of forming the battery can, which is not preferable. From a similar viewpoint, the upper limit of the individual crystal grain size is 2
It is preferably not more than 00 μm. Average grain size is 1
When the thickness is 50 μm or less, the fracture during the formation of the battery can is suppressed, and the effect of increasing the inner surface roughness is 100% for the volume fraction of coarse grains of 30 μm or more, that is, even for a steel sheet composed of only coarse grains. Thus, the upper limit of the volume fraction of coarse crystal grains is not particularly defined.

[0011] Secondly, the present invention has a second feature that at least one surface layer has a layer mainly composed of coarse crystal grains, and the average grain size of the crystal grains constituting the layer is 30 μm or more and 150 μm or less. Is not less than 5% and not more than 40% of the total plate thickness, and the average grain size of the crystal grains constituting the portion other than the layer is 30%.
The present invention provides a battery can-forming steel sheet having a thickness of less than μm.

That is, it is more preferable that the coarse crystal grains exist in a layered form on the surface layer of the material for forming a battery can.
This layered portion is mainly composed of coarse crystal grains,
There is no problem even if crystal grains smaller than 0 μm are included. Specifically, the average crystal grain size in the layer portion is 30 μm or more and 15 μm or more.
The range may be 0 μm or less. A layer mainly composed of coarse crystal grains (hereinafter, abbreviated as a coarse crystal grain layer) is present in a layered form, and a portion other than the layer is composed of crystal grains having a size of less than 30 μm. Without damage, when forming the battery can, if the coarse crystal grain layer is the inner surface of the can,
It is possible to suppress smoothing over the entire inner surface and provide an appropriate roughness.

It is necessary that the thickness of the coarse crystal grain layer is at least 5% of the total thickness. The thickness of the coarse crystal grain layer refers to the thickness of the layered portion existing on the surface layer on one side of the steel sheet. That is, when the layers are provided on the surface layer portions on both sides of the steel sheet, the thickness of each layer is required to be 5% or more of the total sheet thickness, and the total thickness of the layers on both surfaces is required to be 10% or more.

When the thickness of the coarse crystal grain layer is less than 5% of the total plate thickness, the contribution to the increase in roughness after processing as a battery can is very small, and the battery performance is not improved.
More preferably, it is 10% or more. In order to ensure excellent workability, the upper limit of the thickness of the layer is preferably 40% or less. More preferably, it is 30% or less.

The steel sheet for battery can formation according to the first and second aspects of the present invention may be formed into a battery can by press working, followed by plating to form a battery can. Alternatively, the battery can may be formed by pre-plating the steel sheet for forming a battery can to form a plated steel sheet and then pressing. When the plated steel sheet is pressed, the steel sheet having a coarse crystal grain layer on the surface layer is processed such that the surface having the coarse crystal grain layer is at least the inner surface of the can.

The pressing method is not particularly limited, and the so-called transfer processing (multi-step drawing and ironing) combining the above-described multi-step drawing, multi-step drawing and ironing, DI
(Drawing and ironing) Any processing method such as drawing and ironing, stretch draw, or processing combining stretch draw and ironing can be adopted.

When pre-plating is performed, a plating layer is provided on at least one surface of the steel sheet for forming a battery can according to the first invention. In the steel sheet for forming a battery can according to the second aspect, a plating layer is provided on at least a surface of the coarse crystal grain layer.

The plating layer provided by post-plating after processing the steel sheet for forming a battery can is composed of Ni alone, Ni, Mn, Co,
It is composed of two or more alloys of Sn, Se, B, P, Si, Fe, Zn, In, and Bi, and has a plating thickness of 0.1.
It is preferably from 5 μm to 10 μm. If necessary, it is preferable to provide plating layers having different thicknesses on the inner surface side and the outer surface side of the can.

In the case where the steel plate for forming a battery can is pre-plated before processing the battery can, at least one surface of the steel plate for forming a battery can has a thickness of 0.5 to 10 μm, Ni alone or
Ni, Mn, Co, Sn, Se, B, P, Si, Fe,
It is preferable to form a plating layer made of two or more alloys of Zn, In, and Bi. If necessary, a plating layer having a different thickness may be provided on the inner surface side and the outer surface side of the can. When the plating layer is formed only on one surface, the surface is processed to be the inner surface of the can. When a steel sheet having a coarse crystal grain layer as a surface layer is used, plating is performed on at least the surface having the layer, and the plating surface is processed so as to be the inner surface of the can.

A battery can formed by pressing a steel plate for forming a battery can and then performing post-plating, and a battery can formed by pressing a plated steel plate for forming a battery can that has been pre-plated are both coarse and large. By setting the grain size and volume ratio of the crystal grains and the thickness of the coarse crystal grain layer in the above-described appropriate ranges, the average roughness (Ra) in the axial direction of the inner surface of the can after processing can be made 7 μm or more. As described above, by causing the rough surface due to the presence of the coarse crystal grains on the inner surface of the battery can, it is possible to increase the holding power of the carbon powder and the filled active material. In particular, it is important that the roughness in the axial direction of the can be large in order to hold the carbon powder that easily falls off when filling the contents.
When the average roughness (Ra) in the axial direction is 7 μm or more, the carbon powder can be prevented from falling off. From this point, it is more preferable that the average roughness in the axial direction is 10 μm or more. On the other hand, when the outer surface of the battery can is not provided with the coarse crystal grain layer, the outer surface of the battery can maintains smoothness and can obtain a beautiful appearance. In order to further increase the roughness of the inner surface of the battery can, the surface of the steel plate for forming the battery can or the plated steel sheet for forming the battery can, which is on the inner surface side of the battery can, may be subjected to unevenness in advance. A plating layer that generates cracks during can formation may be provided.

Further, the battery manufactured using the battery can has excellent performance because the carbon powder is kept healthy and the contact area between the active material and the inner surface of the can is large.
It can contribute to battery performance improvement. As the above batteries, primary batteries are alkaline dry batteries, lithium primary batteries, air batteries,
Examples of the secondary battery include a Ni-Ca battery, a Ni-MH battery, and a lithium ion battery.

[0022]

Embodiments of the present invention will be described below. FIG. 1 shows an example of an optical microscope image of a cross section in the rolling direction of the steel sheet for forming a battery can of the first embodiment. The battery can-forming steel sheet 10 is made of low-carbon steel and includes coarse crystal grains 11 having a particle size of 30 μm or more. In the steel sheet 10, the coarse crystal grains 11 and relatively fine crystal grains (hereinafter, referred to as fine crystal grains) 21 having a size of less than about 30 μm are unevenly distributed over the entire steel sheet 10, and the volume ratio of the coarse crystal grains 11 is 5%. % Or more. The average crystal grain size of the entire crystal grains (including the coarse crystal grains 11 and the fine crystal grains) of the steel sheet is 150 μm or less.

FIG. 2 shows an example of an optical microscope image of a cross section in the rolling direction of the steel sheet for forming a battery can of the second embodiment. This battery can-forming steel sheet is made of low-carbon steel as in the first embodiment. The difference from the first embodiment is that a layer (referred to as a coarse crystal grain layer) 20 mainly composed of coarse crystal grains 11 provided on the surface layer portion of the steel sheet 10 ′ and a layer (fine crystal grains) 22).

The coarse crystal grain layer 20 is provided on both the front and back surfaces of the steel plate 10 ′, and is formed on the coarse crystal grain layer 20 a formed on the inner surface when the battery can is formed, and on the outer surface. It consists of a coarse crystal grain layer 20b. Although FIG. 2 has a coarse crystal grain layer on both surfaces of the steel sheet, a mode in which only the coarse crystal grain layer 20a is provided only on the inner surface when the battery can is formed may be used.

The coarse crystal grain layer 20 (20a, 20b)
Has an average crystal grain size of 30 μm or more and 150 or more.
μm or less. In addition, each coarse crystal grain layer 20a,
The thickness t2 of Ob is 5% or more and 40% of the total thickness t1, respectively.
It is as follows. The fine crystals 21 have an average particle size of 30.
It is composed of crystal grains of less than μm.

FIG. 3A shows a plated steel sheet 3 according to the third embodiment.
FIG. 2 is a schematic view of the first embodiment, in which a plating layer 31 is provided on one surface of the steel sheet 10 of the first embodiment, and the plating layer 31 is set to an inner surface side when a battery can is formed. FIG. 3B is a modification of the third embodiment, and is made of a plated steel plate 30 ′ in which plated layers 31 and 32 are provided on both surfaces of the steel plate 10 of the first embodiment. The plating layer 31 on the inner side and the plating layer 32 on the outer side when forming the battery can have different types of plating. In the present embodiment, the plating layer 31 is a nickel plating layer, the plating layer 32 is a bright nickel plating layer, and the plating layer 3
The thickness of each of the first and the second 32 is 0.5 μm to 10 μm.

FIG. 4A shows a plated steel sheet 4 according to the fourth embodiment.
FIG. 2 is a schematic diagram of a steel sheet 10 ′ of the second embodiment, in which a plating layer 31 ′ is provided on the surface of a coarse crystal grain layer 20a on one surface, and the plating layer 31 ′ is formed on the inner surface side when a battery can is formed. And FIG. 4B is a modification of the fourth embodiment, in which the coarse crystal grain layers 2 on both surfaces of the steel plate 10 ′ of the second embodiment are shown.
A plating steel plate 40 'provided with plating layers 31' and 32 'on the surfaces of 0a and 20b. The plating layer 31' on the inner surface side and the plating layer 32 'on the outer surface side when the battery can is formed change the type of plating. ing. In this embodiment, the plating layer 3
1 ′ is a nickel plating layer, the plating layer 32 ′ is a bright nickel plating layer, and the thickness of the plating layers 31 ′ and 32 ′ is 0.5 μm to 10 μm.

The type of plating is not limited to nickel plating, but may be Ni alone, Ni, Mn, Co, Sn, or Ni.
It may be formed from two or more alloys of Se, B, P, Si, Fe, Zn, In, and Bi.

As shown in FIG. 5, the battery can-forming materials 10, 10 'of the first and second embodiments are drawn and ironed by D1 to obtain a bottomed cylindrical can having a bottom wall 35a and a peripheral wall 35b. It is processed as 35.

In addition to the above-mentioned DI drawing and ironing processing, multi-drawing processing, so-called transfer processing (multi-step drawing and ironing processing) which combines multi-step drawing and ironing processing, stretch draw processing, or stretch draw and ironing processing is used. Any processing method, such as a processing combining the above, may be selected.

In the steel plates 10, 10 'of the first and second embodiments, since the coarse crystal grains 11 are present on the surface of the steel plate, the inner wall 35b of the peripheral wall 35b of the cylindrical can 35 after processing is formed.
-1 and the surface roughness of both surfaces of the outer surface side 35b-2 are increased. Since the deformation of the steel sheet often starts at the grain boundary,
Due to the presence of the coarse crystal grains 11 of μm or more, deformation during drawing becomes non-uniform, and as a result, irregularities are generated on the surface. When the method including the ironing step is selected as the pressing method, the unevenness of the peripheral wall surface generated before the ironing step changes. Although the change in the surface irregularities of the inner peripheral surface 35b-1 is relatively small, the irregularities of the outer peripheral surface 35b-2 are reduced by the pressing tool, so that the appearance tends to be high in glossiness.

After the first and second steel plates 10 and 10 'are processed as described above, post-plating (glass plating) is performed on the cylindrical can 35, and the inner surface 35b-1, outer surface 35b-2, and bottom wall 35a of the peripheral wall of the cylindrical can 35 are formed. The battery can 50 shown in FIG. 6 is manufactured by providing the plating layers 38 on the inner and outer surfaces of the battery can. The plating type is Ni alone or Ni, Mn, Co, Sn, Se,
B, P, Si, Fe, Zn, In, Bi are formed from two or more alloys, and the plating thickness is 0.5 μm to 10 μm.
And

As described above, when the cylindrical can 35 is subjected to post-plating to form the battery can 50, a plating layer having a substantially uniform thickness is formed on the uneven surface of the inner surface 35a of the can. The unevenness is almost the same as before plating.
The average surface roughness (Ra) of the inner can in the axial direction is 0 μm or more.

The plated steel sheet 3 according to the third and fourth embodiments
The method of forming a battery can using 0 (30 ') and 40 (40') is the same as in the first and second embodiments described above, and press working is performed by an appropriately selected method. Since these already have a plating layer before the press working, a battery can 50 similar to that of FIG. 6 is obtained after the working. The average surface roughness (Ra) of the inner surface of the battery can 50 in the axial direction of the can is 7 μm or more.

The battery can 50 formed by pressing the steel sheet for forming a battery can shown in the first to fourth embodiments has an appropriate surface roughness on the inner surface, so that the carbon powder applied to the inner surface of the battery can is 60 and a filling active material (not shown). In particular, it is important that the surface roughness in the axial direction of the can is large for holding carbon powder which is likely to fall off during filling of the contents. Since the average roughness (Ra) in the axial direction is 7 μm or more, the carbon powder is dropped. It can be stably held without any. Furthermore, a battery manufactured using the battery can has excellent performance because it can strongly hold carbon powder and has a large contact area between the active material and the inner surface of the can.

[0036]

EXAMPLES Low-carbon steel used for general battery can applications was melted and then subjected to hot rolling, pickling and cold rolling. Next, after recrystallization annealing at a temperature equal to or higher than the recrystallization temperature and equal to or lower than the transformation point, temper rolling and annealing are performed under the conditions shown in Table 1 below, and both surfaces of the obtained steel plate are subjected to Ni plating with a thickness of 3 μm. hand,
The steel sheets for forming battery cans of Examples 3 and 7 of the third embodiment, Examples 1, 2, 4 to 6 of the fourth embodiment, and Comparative Examples 1 to 3 were produced.

[0037]

[Table 1]

With respect to the test material obtained in the above manner, the section in the rolling direction was observed with a microscope for each of the examples and comparative examples in five visual fields, and the volume ratio of coarse particles of 30 μm or more was measured for each visual field. The average of the visual field was determined.

For Examples 3 and 7, the average crystal grain size was measured and found to be 150 μm or less. Also,
In Examples 1, 2, 4 to 6 in which a layer mainly composed of coarse crystal grains and having an average particle size of 30 μm or more and 150 μm or less exists in the surface layer portion, the thickness of the layer was measured at any five points, and The average value of the ratio to the thickness was determined. Further, these steel plates were subjected to DI processing to form a battery can, and the average roughness (Ra) in the axial direction of the can at the center of the inner surface of the can in the longitudinal direction of the can was measured. R
The measurement of a was performed using a laser roughness measuring device. Table 2 shows the measurement results of the coarse particle volume ratio and the inner surface Ra of the can. Table 2
Medium and coarse crystal grains refer to crystal grains having a particle size of 30 μm or more.

[0040]

[Table 2]

As shown in Table 2, in Examples 1 to 7, the volume ratio of coarse crystal grains having a particle size of 30 μm or more was 5% or more, specifically 11.4% (Example 5) to 93. 4% (Example 3). In Examples 1, 2, 4 to 7, coarse crystal grain layers which could be clearly distinguished from other parts were present in both surface layer portions of the steel sheet, and the average grain size of the layers was 30 μm or more and 150 μm or less. In Examples 3 and 7, the entire sheet thickness was 30 μm in particle size.
The above coarse crystal grains were distributed, and there was no clearly distinguished layer mainly composed of coarse crystal grains. Also,
The thickness ratio of the layer mainly composed of the coarse crystal grains to the total plate thickness is 5% or more and 40% or less in Examples 1, 2, 4 to 7, and specifically 12.9% (Example 5). It was 25.8% (Example 4). On the other hand, Comparative Examples 1 to 3 have a particle size of 3
The volume ratio of crystal grains of 0 μm or more was less than 5%, and the ratio of the thickness of the layer mainly composed of coarse crystal grains to the total plate thickness was less than 5%. Examples 1 to 7 and Comparative Examples 1 to 3 were DI
The average surface roughness (R
In a), Comparative Examples were less than 7 μm, whereas Examples 1 to 7 were 7 μm or more.

[Evaluation Test] A dry battery was prepared by filling the battery cans of Examples 1 to 7 and the battery cans of Comparative Examples 1 to 3 with active materials, and were continuously discharged at 1.5 A. The properties were evaluated. Table 3 shows the results. In Table 3, the discharge time of Comparative Example 1 was set to 100, and the discharge times of other Examples and Comparative Examples were indicated by indexes.

[0043]

[Table 3]

As shown in Table 3, it was confirmed that Examples 1 to 7 in which the average roughness of the inner surface of the can in the axial direction of the can was 7 μm or more had better discharge characteristics than Comparative Examples 1 to 3.

[0045]

As is apparent from the above description, the steel plate for forming a battery can and the plated steel plate for forming a battery can of the present invention are provided with coarse crystal grains as crystal grains of the steel sheet.
Due to the presence of the coarse crystal grains, the inner surface of the battery can becomes rough when the battery can is formed, so that the holding power of the carbon powder can be increased and the contact area with the active material can be increased.

That is, when the battery can is used for a primary battery, carbon powder is applied to the inner surface of the can. At this time, in the battery can according to the present invention, since the inner surface of the can has a larger surface roughness in the axial direction than before, the holding power of the carbon powder is increased, and peeling or falling off in the content filling step can be prevented. Furthermore, when the battery can is filled with an active material serving as a positive electrode mixture, the battery can according to the present invention has a large inner surface roughness and a larger contact area with the active material than before, so that the resistance of the battery body is reduced. Battery performance. In a secondary battery, even when the outer peripheral surface of the spiral electrode plate housed in the battery can is not parallel to the inner peripheral surface of the battery can, the surface area of the inner surface of the battery can is large. As in the case of the primary battery, the resistance of the battery body decreases, and the battery performance can be improved. As described above, since the surface roughness of the inner surface of the battery can is increased, the battery performance can be improved in any of the primary battery and the secondary battery.

[Brief description of the drawings]

FIG. 1 is a copy of a cross-sectional photograph in the rolling direction of a steel sheet for forming a battery can according to the first embodiment of the present invention.

FIG. 2 is a copy of a cross-sectional photograph in the rolling direction of a steel sheet for forming a battery can according to a second embodiment of the present invention.

FIG. 3A is a schematic sectional view of a plated steel sheet for forming a battery can according to a third embodiment, and FIG. 3B is a schematic sectional view of a modification.

FIG. 4A is a schematic sectional view of a plated steel sheet for forming a battery can according to a fourth embodiment, and FIG. 4B is a schematic sectional view of a modification.

FIG. 5 is a schematic view showing the shape of a steel sheet in an intermediate step of forming a battery can by DI processing.

FIG. 6 is an enlarged cross-sectional view of a main part of a battery manufactured using the bottomed cylindrical battery can of the present invention.

[Explanation of symbols]

 10, 10 'Steel plate for forming battery can 11 Coarse crystal grain 20 Coarse crystal grain layer 21 Fine crystal grain 22 Fine crystal grain layer 35 Bottomed cylindrical can 38 Plating layer 50 Battery can 60 Carbon powder

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[Procedure amendment]

[Submission date] August 25, 2000 (2008.2
5)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Reiko Sugihara 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Susumu Sato 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Sun F-term in Honko Tube Co., Ltd. (Reference) 5H011 AA03 AA04 CC06 DD10 DD18 KK01

Claims (10)

[Claims] 1. The method according to claim 1, wherein the coarse crystal grains have a grain size of 30 μm or more, and the volume fraction of the large crystal grains is 5% or more, and the average crystal grain size of all the crystal grains including the large crystal grains is 150 μm or less. A steel plate for forming a battery can. 2. At least one surface layer has a layer mainly composed of coarse crystal grains, the average grain size of the crystal grains constituting the layer is 30 μm or more and 150 μm or less, and the thickness of this layer is A steel sheet for battery can formation, wherein the steel sheet has a thickness of 5% or more and 40% or less and an average grain size of crystal grains constituting a portion other than the layer is less than 30 μm. 3. The steel sheet for forming a battery can according to claim 1, wherein the steel sheet has a plating layer on at least one surface. 4. The steel sheet for forming a battery can according to claim 2, wherein a plating layer is provided on at least a surface having a layer mainly composed of the coarse crystal grains. 5. A method for producing a battery can, wherein the steel sheet for battery can formation according to claim 1 is pressed to form a cylindrical battery can with a bottom, and then plated. 6. When forming the bottomed cylindrical battery can by pressing the battery can-forming steel sheet according to claim 2, at least the inner surface has a surface having a layer mainly composed of coarse crystal grains, A method for manufacturing a battery can that is plated after the battery can is formed. 7. A battery can having a bottomed cylindrical shape by pressing the steel plate for battery can formation according to claim 3 to produce a battery can having a bottomed cylindrical shape. Method. 8. The battery can-forming steel sheet according to claim 4, which is pressed to form a bottomed cylindrical battery can, wherein at least an inner surface side has a layer mainly composed of coarse crystal grains. A method for manufacturing a battery can as a surface. 9. A battery can obtained by the manufacturing method according to claim 5, wherein the inner surface of the battery can has an average roughness (Ra) in the axial direction of the can of 7 μm or more. A battery can, characterized in that: 10. A battery formed using the battery can according to claim 9.