KR102323071B1 - Metal plate for battery container and method for manufacturing the metal plate for battery container - Google Patents

Abstract

Provided are a metal plate for a battery container and a method for manufacturing the metal plate for a battery container, which can suppress cracking of a base material or peeling of a resin even when a deep drawing process with a small R of the corner is performed using a rolled metal plate. The metal plate for a battery container of the present invention is used as a battery container and is a metal plate made of iron or iron alloy, wherein the metal plate has a thickness of 10 to 100 μm, the tensile strength of the metal plate is 300 to 700 MPa, and the elongation of the metal plate is 5 to 35%, and the ratio of the crystal grain size in the planar direction to the thickness direction of the metal plate is 0.8 to 8.

Description

Metal plate for battery container and method for manufacturing the metal plate for battery container

The present invention relates to a metal plate suitable as a battery container for a lithium ion secondary battery and the like, and a method for manufacturing the metal plate for the battery container.

In recent years, miniaturization of electronic devices has been remarkable, and portable electronic devices such as mobile phones and portable information terminals have been widely used. Such portable electronic devices are equipped with rechargeable batteries as their power sources.

In addition, secondary batteries are not limited to being mounted on the portable electronic devices described above, but are also gradually being mounted on vehicles such as hybrid vehicles and electric vehicles in preparation for the exhaustion of gasoline and environmental problems.

In the secondary battery mounted on the portable electronic device or vehicle described above, a lithium ion secondary battery (hereinafter also referred to as “LiB”) is attracting attention as a high-performance battery having a high output and a long lifespan.

There are various types of lithium ion secondary batteries according to their use, and the battery containers accommodating the non-aqueous electrolyte, the positive electrode active material, the negative electrode active material, and the like also take various forms such as cylindrical or prismatic. Among them, Patent Document 1 discloses a technique for accommodating an electrode or the like in a pouch using a laminate metal plate in which a thin metal plate is coated with a resin. Moreover, according to this patent document 1, the effect of using as a core material of iron or iron alloy metal foil is mentioned.

Further, in Patent Document 2 and Patent Document 3, Ni and Fe are contained on the surface of the rolled metal plate by performing rolling and heat treatment after performing Ni plating on the rolled metal plate using a rolled metal plate having a thickness of 200 µm or less. A technique for forming a diffusion alloy layer is disclosed. In order to improve the corrosion resistance with respect to electrolyte solution etc., although polyolefin resin may be formed on a rolled metal plate, according to this patent document 2, by using the said diffusion alloy layer, the effect of improving the adhesiveness of a rolled metal plate and a polyolefin resin is mentioned.

Patent Document 1: Japanese Patent Laid-Open No. 2001-202932 Patent Document 2: International Publication No. 2016/013572 Patent Document 3: International Publication No. 2016/013575

The secondary battery that can be mounted on the vehicle or electronic device described above is required to have a high capacity in addition to having a high output. Here, in the case where it is only necessary to increase the capacity, it may be sufficient to accommodate the electrode active material corresponding to a relatively large container. However, especially in a secondary battery mounted on a vehicle, since an increase in the weight of the battery itself leads to deterioration of fuel efficiency, it is necessary to suppress the increase in weight as much as possible even in order to realize a high capacity.

As a method of realizing a high capacity while avoiding an increase in weight as much as possible, it is conceivable that deep drawing processing is performed under more stringent conditions to increase the internal capacity of the battery container. In particular, by reducing R of the corner (corner) in the battery container and matching the size of the battery container with the plate-shaped electrode stacking several sheets therein, it becomes possible to increase the battery capacity. However, the prior art including the above-mentioned Patent Documents 1 to 3 cannot be said to be suitable for such deep drawing processing, and there is a large room for improvement. In particular, it has been found that cracks in the base material and peeling of the resin become remarkable when the corners (corners) in the battery container are subjected to deep drawing under severe conditions.

The present invention aims to solve the above problems as an example, and for example, even when deep drawing processing with a small R of the corner is performed using a rolled metal plate, cracking of the substrate or peeling of the resin can be suppressed. An object of the present invention is to provide a metal plate for a battery container and a method for manufacturing the metal plate for a battery container.

The metal plate for a battery container of the present invention for solving the above problems is (1) a metal plate made of iron or an iron alloy used as a battery container, the thickness of the metal plate being 10 to 100 μm, and the tensile strength of the metal plate is 300 to 700 MPa, the elongation of the metal plate is 5 to 35%, and the ratio of the crystal grain size in the planar direction to the thickness direction of the metal plate is 0.8 to 8.

Moreover, in the metal plate for battery containers of said (1), it is preferable to have a surface treatment layer containing Cr or Ni in (2) the said metal plate.

Moreover, in the metal plate for battery containers of said (1) or (2), it is preferable that (3) the said metal plate is coat|covered with the thermoplastic resin.

Moreover, in the metal plate for battery containers of said (3), it is preferable that (4) said thermoplastic resin contains a polyolefin resin or polyester resin.

Moreover, in the metal plate for battery containers of said (4), it is preferable that (5) the said polyolefin resin or polyester-type resin coat|covers both surfaces of the said metal plate.

In addition, in the metal plate for battery containers of (5), (6) the polyolefin-based resin covering one side of the metal plate is a polypropylene resin, and the polyester-based resin covering the other side of the metal plate is It is preferable that it is a polyethylene terephthalate resin.

Moreover, in the metal plate for battery containers of said (6), it is preferable that the said polyester resin (7) is non-oriented.

Moreover, in the metal plate for battery containers in any one of said (3)-(7) WHEREIN: (8) It is preferable that the thickness of the said thermoplastic resin is 10-50 micrometers.

In addition, in order to solve the above problems, the method for manufacturing a metal plate for a battery container of the present invention is a method for manufacturing a metal plate for a battery container made of a metal plate of iron or iron alloy, the metal plate is cold-rolled to reduce the thickness of 10 a first step of ˜100 μm, and a second step of annealing the metal plate after the first step, wherein the tensile strength of the metal plate is 300 to 700 MPa, the elongation of the metal plate is 5 to 35%, and It is characterized in that the metal plate is softened so that the ratio of the crystal grain size in the planar direction and the thickness direction of the metal plate is 0.8 to 8.

Further, in the above-described method for manufacturing a metal plate for a battery container, it is preferable to have a third step of forming a surface treatment layer on the metal plate after the first step, before or after the second step.

According to the present invention, it is possible to suppress cracking of the substrate or peeling of the resin even when a deep drawing process with a small R of the corner is performed using a rolled metal plate.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the metal plate for battery containers which concerns on embodiment.
2 is a flowchart illustrating a method for manufacturing a metal plate for a battery container according to an embodiment.
3 is a material No. photographed under a microscope. It is a cross-sectional picture at A.
4 is a view showing an outline of a battery container molded using the metal plate for battery container according to the embodiment.
5 is a material No. photographed under a microscope. It is a cross-sectional photograph at E.

Hereinafter, the metal plate 1 for battery containers of this embodiment is demonstrated using FIG. In addition, in FIG. 1, for convenience, the thickness direction of the metal plate 1 for battery containers is made into a Z direction, and the rolling direction of the metal plate 1 for battery containers is further demonstrated as X direction. However, defining these directions does not reduce the scope of the present invention.

<Metal plate for battery container>

The metal plate 1 for battery containers according to the present embodiment is made of iron or an iron alloy. As the iron alloy, various steel plates applicable as a base material for a battery container can be exemplified, for example, low-carbon aluminum killed steel (a carbon content of 0.01 to 0.15% by weight), a pole having a carbon content of 0.003% by weight or less Non-aging ultra-low carbon steel, etc. made by adding Ti and Nb in addition to low-carbon steel or ultra-low-carbon steel shall also be included.

Moreover, the thickness of the metal plate 1 for battery containers which concerns on this embodiment is 10-100 micrometers, More preferably, it is 15-60 micrometers. When the thickness is less than 10 µm, the quality tends to be unstable, such as pinholes occurring in the cold rolling process or the difference in the gradient of the plate thickness becoming unstable. Moreover, there exists a possibility that a crack may generate|occur|produce in a shaping|molding process and the effect made into the objective of this application may not be acquired. On the other hand, it is because the effect of weight reduction is not acquired when thickness exceeds 100 micrometers.

Here, an example of the component composition in the case where the metal plate 1 for battery containers is an iron alloy is as follows.

(C: 0.0001 to 0.1 wt%)

C is an element which raises the intensity|strength of the metal plate 1 for battery containers. When the content of C is excessive, the strength increases too much and the rollability decreases, so the upper limit of the C content is set to 0.1%. On the other hand, the lower limit of the C content is not particularly limited, but considering the cost, the lower limit of the C content is 0.0001% by weight. Moreover, content of C becomes like this. More preferably, it is 0.001 to 0.01 weight%.

(Si: 0.001 to 0.5 wt%)

Si is an element which raises the intensity|strength of the metal plate 1 for battery containers. If the content of Si is excessive, the strength increases too much and the rollability decreases, so the upper limit of the Si content is set to 0.5% by weight. On the other hand, the lower limit of the Si content is not particularly limited, but considering the cost, the lower limit of the Si content is 0.001% by weight. Moreover, content of Si becomes like this. More preferably, it is 0.001 to 0.02 weight%.

(Mn: 0.01 to 1.0 wt%)

It is an element which raises the intensity|strength of the metal plate 1 for Mn battery containers. When the content of Mn is excessive, the strength increases too much and the rollability decreases, so the upper limit of the Mn content is set to 1.0% by weight. On the other hand, the lower limit of the Mn content is not particularly limited, but considering the cost, the lower limit of the Mn content is 0.01 wt%. Further, the content of Mn is more preferably 0.01 to 0.5% by weight.

(P: 0.001 to 0.05 wt%)

P is an element which raises the intensity|strength of the metal plate 1 for battery containers. When the content of P becomes excessive, the strength increases too much and the rollability decreases, so the upper limit of the content of P is set to 0.05% by weight. On the other hand, the lower limit of the P content is not particularly limited, but considering the cost, the lower limit of the P content is 0.001 wt%. Moreover, content of P becomes like this. More preferably, it is 0.001 to 0.02 weight%.

(S: 0.0001~0.02 wt%)

S is an element which reduces the corrosion resistance of the metal plate 1 for battery containers. Therefore, it is so preferable that the content of S is small. In particular, when the S content exceeds 0.02 wt%, the corrosion resistance deteriorates significantly, so the upper limit of the S content is set to 0.02 wt%. On the other hand, the lower limit of the S content is not particularly limited, but considering the cost, the lower limit of the S content is 0.0001 wt%. Moreover, content of S becomes like this. More preferably, it is 0.001 to 0.01 weight%.

(Al: 0.0005 to 0.20 wt%)

Al is added as a deoxidation element of the metal plate 1 for battery containers, for example. In order to obtain the effect by deoxidation, it is preferable that the content of Al be 0.0005 wt% or more. However, since rollability will fall when Al content becomes excessive, the upper limit of Al content is made into 0.20 weight%. On the other hand, the lower limit of the Al content is not particularly limited, but considering the cost, the lower limit of the Al content is 0.0005 wt%. Further, the content of Al is more preferably 0.001 to 0.10%.

(N: 0.0001 to 0.0040 wt%)

N is an element which reduces the workability of the metal plate 1 for battery containers. Therefore, it is so preferable that there is little content of N. In particular, when the content of N exceeds 0.0040% by weight, the decrease in workability becomes remarkable, so the upper limit of the content of N is set to 0.0040% by weight. On the other hand, the lower limit of the N content is not particularly limited, but in consideration of cost, the lower limit of the N content is set to 0.0001 wt%. Moreover, content of N becomes like this. More preferably, it is 0.001 to 0.0040 weight%.

(Remainder: Fe and unavoidable impurities)

Among the remainder of the metal plate 1 for battery container, the main element is Fe, and other impurities are unavoidably mixed during manufacture.

As other additional components, Ti, Nb, B, Cu, Ni, Sn, Cr, etc. may be contained. In particular, Ti and Nb fix C and N in the metal plate 1 for battery container as carbides and nitrides, and have an effect of improving the workability of the metal plate 1 for battery container, Ti: 0.01 to 0.8 wt%, Nb : You may contain 1 type or 2 types in the range of 0.005-0.05 weight%. Moreover, the metal plate 1 for battery containers which concerns on this embodiment is more preferable than the steel plate whose Cr is 10.5% or less.

Moreover, the metal plate 1 for battery containers which concerns on this embodiment is annealed after cold rolling, and has the following characteristics. In addition, the temperature and time required for the annealing of this embodiment are 2-9 hours, More preferably, 2-6 hours when carrying out at 450 degreeC - 650 degreeC (more preferably 500-600 degreeC). In addition, when performing annealing at 700 ~ 800 ℃, the required time is 20 ~ 120 seconds.

(tensile strength)

The tensile strength of the metal plate 1 for battery containers according to the present embodiment is 300 to 700 MPa. When the tensile strength is less than 300 MPa, when it is used as a battery container, when it is deformed by an external force, cracks and holes are generated, and thus, there is a problem that leakage of the electrolyte solution or the like occurs. Moreover, it is because workability will become insufficient when tensile strength exceeds 700 MPa. Moreover, the tensile strength of the metal plate 1 for battery containers becomes like this. More preferably, it is 350-650 MPa. When workability is required more, More preferably, it is 350-450 MPa.

In addition, the tensile strength of the metal plate 1 for battery containers was implemented according to "Metal material tensile test method" described in Z2241 of JIS standard.

(elongation)

The elongation of the metal plate 1 for battery containers which concerns on this embodiment is 5-35 %. This is because when the elongation of the metal plate 1 for battery container is less than 5%, the workability becomes insufficient at the corner (corner) portion, and there is a possibility that cracks may occur during processing. This is because, when the elongation is 36% or more, high temperature and long time are required as annealing conditions for producing such characteristics, and productivity deteriorates. Moreover, the elongation of the metal plate for battery containers becomes like this. More preferably, it is 5 to 20 %. In particular, when the thickness of the metal plate 1 for battery containers is thin, 5 to 15 % is preferable, More preferably, it is 7 to 12 %.

In addition, the elongation of the metal plate 1 for battery containers was performed according to "20: Elongation at break (%) A measurement formula (7)" of "Method for tensile test of metal materials" described in Z2241 of JIS standard.

(Ratio of crystal grain size)

The ratio (planar direction/thickness direction) of the crystal grain size in the planar direction (rolling direction) and the thickness direction of the metal plate 1 for battery containers which concerns on this embodiment is 0.8-8. In addition, the "crystal grain size" in this embodiment is an average value of the crystal grain sizes existing per unit area (for example, 1 micrometer phi 1 micrometer). Although there is no restriction|limiting in particular in the method of measuring this average grain size, For example, after taking a cross-sectional photograph of a metal plate with a scanning electron microscope (SEM), it can measure according to JIS G0551 (Annex B or C). To obtain the ratio in the planar direction (rolling direction) and the thickness direction, the crystal grain size is obtained based on each of the test line along the planar direction and the test line along the thickness direction, and the ratio is calculated. Further, in each of the plurality of grains to be measured, the ratio of the crystal grain sizes described above may be calculated by comparing the longest length value in the rolling direction with the longest length value in the thickness direction.

It is difficult in a general manufacturing method to make the ratio of the above-mentioned crystal grain size of the metal plate 1 for battery container to be less than 0.8. Moreover, when the ratio of the above-mentioned crystal grain size exceeds 8, cracks are likely to occur during processing. Moreover, ratio of said crystal grain size of the metal plate 1 for battery containers becomes like this. More preferably, it is 0.8-5. When more workability is requested|required, ratio of the said crystal grain size of the metal plate 1 for battery containers is 0.8-4 more suitably.

<Surface treatment layer>

The surface treatment layer 2 may be formed on the metal plate 1 for battery containers according to the present embodiment. As this surface treatment layer 2, Cr plating or Ni plating is mentioned, for example, in order to improve adhesiveness with resin formed thereon, It is good also as a single layer or these multiple layers, and corrosion resistance on these or instead of these. Treatment layer for improvement (e.g., Ni-Co plating layer, Zn plating or Zn-based plating layer such as Zn-Ni, Zn-Co plating, Sn plating treatment layer, dispersion plating treatment between these plating and the underlying metal) layer, a chemical conversion layer for forming an oxide film, a silane coupling agent-treated layer, etc.) may be formed. In addition, the surface treatment layer of this embodiment may be formed after the metal plate 1 for battery containers is annealed after cold rolling, for example, It is also formed before annealing after the metal plate 1 for battery containers is cold-rolled. possible. In addition, although the surface treatment layer 2 is formed on both surfaces of the metal plate 1 for battery containers in FIG. 1, the aspect in which the surface treatment layer 2 is formed in at least one side may be sufficient.

In addition, when performing Ni plating on the metal plate 1 for battery containers, after electrolytic degreasing and pickling of the cold-rolled metal plate by a normal method, for example, the Ni plating bath shown below can be used as an example. have. As the Ni plating bath, a nickel sulfate bath called a watt bath is mainly used, but a sulfamic acid bath, a boron fluoride bath, a chloride bath or the like may be used.

(Composition of Ni plating bath, and conditions)

Nickel sulfate: 200-350 g/l

Nickel Chloride: 20~60g/l

Boric acid: 10-50 g/l

pH: 1.5-5.0

Bath temperature: 40~70℃

Current Density: 1-40 A/dm ²

In addition, the surface treatment layer 2 formed on the metal plate 1 for battery container may be formed at least on the surface used as the inner surface of the container in the metal plate 1 for battery container, but may be formed on both the outer and inner surfaces of the container. do. In addition, nickel plating as the surface treatment layer 2 formed on the metal plate 1 for battery container is formed using not only pure Ni, but also an alloy containing Ni such as a Ni-Co alloy or an Fe-Ni alloy. also be

Moreover, the thickness of the nickel plating of this embodiment becomes like this. Preferably it is 0.1-5 micrometers. About this lower limit, More preferably, it is 0.3 micrometer, More preferably, it is 0.5 micrometer. On the other hand, about an upper limit, More preferably, it is 3 micrometers, More preferably, it is 1 micrometer.

Moreover, when heat-processing after forming nickel plating as the surface treatment layer 2 on the metal plate 1 for battery containers, an Fe-Ni diffusion layer is formed. From the viewpoint of improving workability, the Fe-Ni diffusion layer preferably has a thickness of 0.2 µm or more, and further preferably has a thickness of 0.5 µm or more.

In addition, when performing Cr plating on the metal plate 1 for battery containers, the cold rolled metal plate is electrolytically degreased and pickled by a conventional method, and then, for example, the Cr plating bath shown below can be used as an example. have. In this case, as for the thickness of Cr plating as the surface treatment layer 2, 0.05-1.0 micrometer is suitable.

(Composition of Cr plating bath, and conditions)

CrO ₃ : 30~200g/l

NaF: 5-10 g/l

Bath temperature: 35~65℃

Current density: 5-50A/dm ²

<Thermoplastic resin>

At least one side of the metal plate 1 for battery container according to the present embodiment may be coated with the thermoplastic resin 3 . The thickness of such a thermoplastic resin 3 is 10-50 micrometers, More preferably, it is 10-30 micrometers.

In addition, as the thermoplastic resin 3 of this embodiment, polyolefin resin, polyester resin, or polyamide resin can be illustrated. And it is preferable that this polyolefin resin, polyester resin, or polyamide resin coat|covers both surfaces of the metal plate 1 for battery containers. In this case, it is preferable that one side (the inner surface side of the battery cylinder) of the metal plate 1 for a battery container is coat|covered with polypropylene resin. On the other hand, it is preferable that the other side (outer surface side of a battery cylinder) of the metal plate 1 for battery containers is coat|covered with a polyester resin, especially polyethylene terephthalate. Moreover, as a polyester resin, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, etc. other than polyethylene terephthalate can be used, for example. Moreover, you may use modified resins, such as a urethane modified polyester resin, an acrylic modified polyester resin, and an epoxy modified polyester resin.

In addition, the thickness of the resin covering one side (for example, the inner surface side of the battery container) of the battery container metal plate 1, and the thickness of the resin covering the other surface (for example, the outer surface side of the battery container), What is necessary is just to adjust suitably within the said thickness range according to the corrosion resistance and workability requested|required, and the thickness of both surfaces may be same or different.

Moreover, when using a polyester resin, it is preferable that this polyester resin is non-oriented.

In addition, the other side (outer surface side of the battery barrel) of the metal plate 1 for battery container is not limited to the above-mentioned polyester resin (polyethylene terephthalate), Polypropylene resin on both surfaces of the metal plate 1 for battery container may be covered. Alternatively, both surfaces of the metal plate 1 for battery containers may be coated with a polyester resin.

Moreover, the form which coat|covers the metal plate 1 for battery containers via a well-known adhesive agent may be sufficient as the thermoplastic resin 3 . Moreover, as a well-known adhesive agent, inorganic adhesives, such as an acid-modified polyolefin resin, an epoxy resin, an acrylic resin, a urethane resin, a silicone resin, a polyisobutylene resin, a fluororesin, or water glass, etc. can be used, for example.

The thermoplastic resin 3 may be laminated on the metal plate 1 for battery container after forming a film, and the thermoplastic resin melted by heating is extruded into a film shape by a slit of the extrusion width of an extrusion molding machine, and directly What is based on the extrusion lamination|stacking method laminated|stacked on the metal plate 1 may be sufficient. When laminating after forming the said film, it does not restrict|limit especially as said film, For example, an unstretched film may be sufficient, a uniaxially stretched film, or a biaxially stretched film may be sufficient.

<Method for manufacturing metal plate for battery container>

Next, the manufacturing method of the metal plate for battery containers of this embodiment is demonstrated, referring FIG.

First, a metal plate made of iron or an iron alloy is prepared, and cold rolling is performed by putting the metal plate into a rolling mill for performing press working (step 1). For this reason, the metal plate 1 for battery containers by which the thickness of 10-100 micrometers was cold-rolled is formed. This cold rolling may be performed in multiple steps as needed, and you may heat-process in between.

Next, the metal plate 1 for battery containers is annealed (step 2). At this time, the temperature of the metal plate 1 for battery containers in an annealing process is 450 degreeC - 650 degreeC, More preferably, it is 500-600 degreeC. Moreover, the required time in this annealing process is 2 to 9 hours, More preferably, it is 2 to 6 hours. In addition, when performing an annealing process at 700-800 degreeC, although it can also carry out for 20 to 120 second, it is preferable to carry out in the former temperature range from a viewpoint of workability improvement.

After step 2, the surface treatment (plating treatment) is preferably applied to the metal plate 1 for a battery container to form a surface treatment layer 2 on the metal plate 1 for a battery container (step 3). At this time, a Ni plating layer is formed as the surface treatment layer 2 on the metal plate 1 for battery containers, for example.

Moreover, as thickness of the surface treatment layer 2 formed in step 3, if it is a Ni plating layer, it is 0.1-5 micrometers, and if it is a Cr plating layer, 0.05-1.0 micrometer is suitable, for example. Note that the annealing in step 2 may be performed after the surface treatment layer 2 is formed. Moreover, after performing the annealing of step 2 and forming the surface treatment layer 2, you may further perform heat processing for the purpose of improving the workability of a Ni plating layer, for example. As the heat treatment conditions after Ni plating, it is possible to carry out under the same conditions as the annealing conditions described in step 2.

Moreover, when the rolling process of step 1 is performed after a plating process, a crack may arise on the surface of a Ni plating film, and adhesiveness and corrosion resistance may fall, and it is unpreferable.

In addition, the metal plate 1 for battery containers after going through steps 2 and 3 has a tensile strength of 300 to 700 MPa, an elongation of 5 to 35%, and the planar direction (rolling direction) and thickness of the metal plate 1 for battery containers. It has a characteristic that the ratio of grain size in the direction is 0.8 to 8.

Next, with respect to the metal plate 1 for battery container on which the surface treatment layer 2 is formed in step 4, the above-described thermoplastic resin 3 is coated with a thickness of about 10 to 50 µm (resin coating treatment). Conduct. More specifically, a polypropylene resin is formed on one side of the metal plate for a battery container (1), which is the inner side of the container, and a polyethylene terephthalate resin or a polypropylene resin is formed on the other side that becomes the outer surface of the container. . As the formation method of resin, as mentioned above, film lamination|stacking may be sufficient, and the method by extrusion lamination|stacking may be sufficient. In addition, the temperature of the metal plate 1 for battery containers at the time of coat|covering this thermoplastic resin 3 is adjusted to 200-280 degreeC.

And in step 5, a deep drawing process is performed and the metal plate 1 for battery containers is shape|molded into the container shape as shown in FIG. More specifically, the container shape of the present embodiment has rectangular concave portions having a depth D in which corner portions having a radius of curvature R are formed at the four corners so as to accommodate a rectangular electrode plate. In addition, in the container of FIG. 4, although R of the four corners becomes the same, it is good also considering the R of these four corners respectively as a different value.

In addition, although the battery container is sealed after accommodating an electrode plate and battery elements, such as electrolyte solution, the metal plate 1 for battery containers of this embodiment is applicable also as a lid member of the battery container used for sealing. The lid member which is a structural member of such a battery container may form the same accommodation space as the battery container body shown in FIG. 4, and may use it as a flat plate. Moreover, when sealing a battery container, it is preferable to heat-seal with the above-mentioned lid member at the peripheral flange part of the battery container main body which has the drawing-processed accommodating part. In this case, it is preferable that the coating resin of the surface where the battery container main body and the lid member face each other may be comprised so that resin of the same type may face each other, such as polypropylene resin or polyester resin. In addition, said sealing method is an example, It is not limited to this, For example, you may use a well-known adhesive agent.

Since the battery container obtained in this embodiment is formed by using the battery container metal plate 1 of this embodiment described above, the adhesion between the nickel-plated metal plate or the chromium-plated metal plate and the resin is high, and, nevertheless, it is excellent in mass production processability. . Therefore, it can use suitably as a battery container of various primary batteries, such as an alkaline battery, a nickel-hydrogen battery, a nickel-cadmium battery, and a lithium ion battery, or a secondary battery.

Example

Next, an Example is given and this invention is demonstrated more concretely. First, material No. used in Examples or Comparative Examples to be described later. A-Material No. The manufacturing conditions of the metal plate 1 for battery containers of F are described in the following Table 1.

Material No. write Plated Annealing conditions
(℃, h) tensile strength
(MPa) Elongation (%) Ratio of grain size in plane direction and thickness direction type of equipment thickness
(μm) type of plating thickness
(μm) A cold rolled steel 25 Ni plating One 600℃, 3h 390 10 1.2 B Cr plating 0.1 C Ni plating One 550℃, 3h 390 11 3 D 450℃, 3h 630 5.5 5 E not done 780 3 10 F aluminum does not exist 60 5 -

<Material No. A>

Material No. As A, first, as a base material, a low-carbon aluminum killed steel cold-rolled sheet (25 µm in thickness) having the chemical composition shown below was prepared.

C: 0.04% by weight, Mn: 0.32% by weight, Si: 0.01% by weight, P: 0.012% by weight, S: 0.014% by weight, balance: Fe and unavoidable impurities

Next, the prepared base material was subjected to electrolytic degreasing and acid washing by immersion in sulfuric acid, and then Ni plating was performed under the following conditions to form a surface treatment (Ni plating) layer 2 having a thickness of 1.0 µm. In addition, Ni plating conditions were carried out as follows.

(Nickel plating conditions)

Bath composition: nickel sulfate, nickel chloride, boric acid, pit inhibitor

pH: 4.0-4.6

Bath temperature: 60°C

Current density: 25-30 A/dm ²

The metal plate 1 for battery containers which has the following characteristics was obtained by performing annealing at 600 degreeC for 3 hours with respect to the base material with a Ni plating layer.

· Tensile strength: 390 MPa

· Elongation: 10%

· Ratio of grain size in planar (rolling) direction and thickness direction: 1.2

In addition, as shown in Figs. 3 and 5, the crystal grain size was obtained by taking a cross-sectional photograph of the metal plate 1 for battery container with a scanning electron microscope (SEM), and then according to JIS G0551 (Annex C), in the planar direction and It measured about each thickness direction.

Material No. As for B to E, material No. Using the same substrate as A, and changing the plating conditions and heat treatment conditions as follows, Material No. B to E were prepared respectively.

<Material No. B>

Material No. In B, material No. Instead of the nickel plating layer of A, a Cr plating layer as the surface treatment layer 2 having a thickness of 0.1 µm was formed under the following conditions.

(Chrome plating condition)

Chrome plating bath: CrO ₃ : 100 g/l, NaF: 5 g/l

bath temperature: 40°C;

Current density: 50 A/dm ²

After that, material No. In the same manner as in A, annealing was performed at a temperature of 600°C for 3 hours to obtain a metal plate for battery containers (1) having the following characteristics.

·Tensile strength: 390 MPa

・Elongation rate: 10%

·Ratio of grain size in plane (rolling) direction and thickness direction: 1.2

<Material No. C>

Material No. In C, except that the annealing condition was set to 3 hours at a temperature of 550°C, the material No. It carried out similarly to A, and the metal plate 1 for battery containers which has the following characteristics was obtained.

·Tensile strength: 390 MPa

・Elongation rate: 11%

·Ratio of grain size in plane (rolling) direction and thickness direction: 3

<Material No. D>

Material No. In D, material No. except that the annealing condition was set to 3 hours at a temperature of 450°C. It carried out similarly to A, and the metal plate 1 for battery containers which has the following characteristics was obtained.

·Tensile strength: 630MPa

· Elongation: 5.5%

·Ratio of grain size in plane (rolling) direction and thickness direction: 5

<Material No. E>

Material No. In E, material No. except that annealing was not performed. It carried out similarly to A, and the metal plate 1 for battery containers which has the following characteristics was obtained.

·Tensile strength: 780MPa

・Elongation rate: 3%

·Ratio of grain size in plane (rolling) direction and thickness direction: 10

<Material No. F>

Material No. In F, a pure aluminum plate (JIS H4000 alloy No. A1050, O material) having a thickness of 25 μm having the following composition is used as a metal plate 1 for battery containers without forming a surface treatment layer and without annealing. did.

This material No. The characteristics of F are as follows. In addition, material No. Regarding F, the crystal grain size was not measured.

·Tensile strength: 60MPa

· Elongation: 5%

Next, the material No. obtained in this way. A-Material No. With respect to the metal plate for battery container 1 using F, a polypropylene resin is formed on one side of the metal plate for battery container 1 that is the inner side of the container, and polyethylene terephthalate resin is formed on the other side that becomes the outer surface of the container. each formed. In addition, the lamination|stacking temperature (temperature of the metal plate 1 for battery containers) at this time was 260 degreeC.

(Processed into battery containers)

As for the metal plate 1 for battery container in which the thermoplastic resin 3 is formed on both sides as described above, as shown in FIG. 4 , the external dimensions are vertical H = 70 mm Х width W = 70 mm, at the four corners of the battery container. The radius of curvature R of 12.5, 15, 20, and 25 mm was respectively processed. At this time, the depth D was drawn in the range of 4-17 mm, and the battery container was formed.

In addition, when processing into a battery container, when the depth of drawing process is D and the radius of curvature is R, it was found that the D/R value becomes important. More specifically, the larger the D/R value, the more difficult the processing becomes, but it becomes possible to form a battery container with a larger capacity. Based on this knowledge, the value of D/R becomes like this. Preferably it is 0.4 or more, More preferably, it is 0.9 or more. For this reason, the capacity|capacitance as a battery container can be enlarged.

(Evaluation method after processing)

The evaluation after processing was evaluated by visually observing cracks in the base material and floats and cracks in the thermoplastic resin at the four corners of the battery container.

In addition, evaluation was performed on the following reference|standard (The other Example and comparative example mentioned later are also the same).

[Evaluation standard]

3 points|pieces: As a result of visual judgment, the crack of a base material and the float/crack of a thermoplastic resin were not recognized.

2 points|pieces: As a result of visual judgment, although it can use practically, a crack and a float were confirmed in part.

1 point|piece: As a result of visual judgment, the crack of a base material and the float/crack of a thermoplastic resin were confirmed to the extent that it cannot be used practically.

material specification Drawing processing conditions Machining result Material No. Inner side resin / Outer surface side resin Thickness (㎛) Depth (mm) R12.5 R15 R20 R25 Example One A PP/PET 30/12 11 3 3 3 3 2 PP/PET 30/12 15 3 3 3 3 3 PP/PET 30/12 17 3 3 3 3 4 PP/PET 30/30 17 3 3 3 3 5 PP/PET 30/30 17 3 3 3 3 6 B PP/PET 30/12 17 3 3 3 3 7 C PP/PET 30/12 11 3 3 3 3 8 D PP/PET 30/12 5 3 3 3 3 9 PP/PET 30/12 6 2 3 3 3 10 PP/PET 30/12 7 2 2 3 3 11 PP/PET 30/12 11 2 2 2 2 comparative example One E PP/PET 30/12 4 One One 3 3 2 PP/PET 30/12 5 One One 3 3 3 PP/PET 30/12 6 One One One One 4 PP/stretched PET 30/19 5 One One 2 2 5 F PP/PET 30/12 4 One One 3 3 6 PP/PET 30/12 5 One One 3 3 7 PP/PET 30/12 6 One One One One

<Example 1>

Material No. shown in Table 1 as the metal plate 1 for battery containers. A was used. In addition, a polypropylene resin is formed to a thickness of 30 μm on one side of the metal plate 1 for a battery container, which is the inner side of the container, and a polyethylene terephthalate resin is formed with a thickness of 12 μm on the other side that becomes the outer surface of the container. each formed. In addition, the lamination|stacking temperature (temperature of the metal plate 1 for battery containers) at this time was 260 degreeC.

And the depth at the time of a drawing process was 11 mm, and it processed into the battery container.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Example 1.

<Example 2>

It implemented similarly to Example 1 except having made the depth at the time of a drawing process 15 mm.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Example 2.

<Example 3>

It implemented similarly to Example 1 except having made the depth at the time of a drawing process 17 mm.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Example 3.

<Example 4>

It implemented similarly to Example 1 except having made the thickness of the polyethylene terephthalate resin formed in the outer surface side of a battery container 30 micrometers, and having made the depth at the time of a drawing process 17 mm.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Example 4.

<Example 5>

Except that the thickness of the polypropylene resin formed on the inner surface side of the battery container is 20 µm, the thickness of the polyethylene terephthalate resin formed on the outer surface side of the battery container is 30 µm, and the depth at the time of drawing is 17 mm, It implemented similarly to Example 1.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Example 5.

<Example 6>

Material No. shown in Table 1 as a metal plate for battery containers. Using B, it implemented similarly to Example 1 except having made the depth at the time of a drawing process 17 mm.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Example 6.

<Example 7>

Material No. shown in Table 1 as a metal plate for battery containers. Except having used C, it implemented similarly to Example 1.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Example 7.

<Example 8>

Material No. shown in Table 1 as a metal plate for battery containers. Using D, it implemented similarly to Example 1 except having made the depth at the time of a drawing process 5 mm.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Example 8.

<Example 9>

It implemented similarly to Example 8 except having made the depth at the time of a drawing process 6 mm.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Example 9.

<Example 10>

It implemented similarly to Example 8 except having made the depth at the time of a drawing process 7 mm.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Example 10.

<Example 11>

It implemented similarly to Example 8 except having set it as the depth of 11 mm at the time of a drawing process.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Example 11.

<Comparative Example 1>

Material No. shown in Table 1 as a metal plate for battery containers. Using E, it implemented similarly to Example 1 except having made the depth at the time of a drawing process 4 mm.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Comparative Example 1.

<Comparative Example 2>

It implemented similarly to the comparative example 1 except having made the depth at the time of a drawing process 5 mm.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Comparative Example 2.

<Comparative Example 3>

It implemented similarly to the comparative example 1 except having made the depth at the time of a drawing process 6 mm.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Comparative Example 3.

<Comparative Example 4>

It implemented similarly to Comparative Example 1 except that the resin formed on the outer surface side of a battery container was 19 micrometers-thick stretched polyethylene terephthalate resin, and having made the depth at the time of a drawing process 5 mm.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Comparative Example 4.

<Comparative Example 5>

Material No. shown in Table 1 as a metal plate for battery containers. Except having used F, it implemented similarly to Comparative Example 1.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Comparative Example 5.

<Comparative Example 6>

It implemented similarly to the comparative example 5 except having made the depth at the time of a drawing process 5 mm.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Comparative Example 6.

<Comparative Example 7>

It implemented similarly to the comparative example 5 except having made the depth at the time of a drawing process 6 mm.

Table 2 shows the evaluation of material specifications, drawing processing conditions, and processing results in Comparative Example 7.

As shown in Table 2, in Examples 1-11, favorable processing results were obtained at the four corners of the battery cylinder. This means that a space for accommodating power generation elements (electrode plate spacers, electrolytes, etc.) in the battery container can be secured as much as possible while ensuring corrosion resistance to the electrolyte and adhesion between the resin and the substrate.

On the other hand, in Comparative Examples 1-7, in particular, the smaller the radius of curvature, the worse the processing results, and it was found that the properties were not sufficient for practical use.

In addition, the present inventors paid attention to the relationship between the depth D of the drawing process and the radius of curvature R at the four corners of the battery barrel, and the ratio of these (ratio of the depth D of the drawing process to the radius of curvature R (D/R)) was considered about D/R can indicate the degree of processing, and the larger the depth D, and the smaller the R, that is, the larger the D/R, the more difficult the processing. And when the radius of curvature R was changed (R12.5, R15, R20 and R25), these ratios (D/R) were put together in Table 3 shown below.

Moreover, the ratio (D/R) of the total thickness (micrometer) of the metal plate for battery containers used in Examples 1-11 and Comparative Examples 1-7, and the ratio (D/R) of the depth of drawing process and the radius of curvature R (total plate thickness/drawing) The ratio of the machining depth D and the radius of curvature R) is also summarized in Table 3.

Based on this Table 3, it can be said that the present invention has the following characteristics.

(a) At the same plate thickness, under the conditions stipulated in Examples, even if the ratio (D/R) of the depth D of the drawing process to the radius of curvature R (D/R) is 0.4 or more, machining is possible, and in Examples 3 to 6, at least A D/R of 1.4 has been proven to be possible. This suggests that, for example, in the case of a container shape in which the radius of curvature R of the corner of the battery container is 5 mm, the depth D of the drawing process can be molded to about 7 mm. On the other hand, under the conditions stipulated in the comparative example, the ratio (D/R) of the depth of the drawing process to the radius of curvature R (D/R) is limited to 0.3.

(b) In relation between the total plate thickness, the depth of the drawing process, and the ratio (D/R) of the radius of curvature R, it has been demonstrated that machining can be performed at least 0.05 or more under the conditions stipulated in the examples. On the other hand, if it is not 0.28 or more under the conditions prescribed|regulated by the comparative example, processing will become difficult.

As described above, the metal plate for a battery container and the method for manufacturing the same of the present invention can exhibit good characteristics even when deep drawing processing with a small radius of curvature R of the corner is performed using a rolled metal plate, and using a battery It can be applied to a wide range of industries.

1: Metal plate for battery container
2: surface treatment layer
3: Thermoplastic resin

Claims (10)

A metal plate made of iron or iron alloy used as a battery container, comprising:
In the metal plate, C is 0.0001 to 0.1 wt%, Si is 0.001 to 0.5 wt%, Mn is 0.01 to 1.0 wt%, P is 0.001 to 0.05 wt%, S is 0.0001 to 0.02 wt%, Al is 0.0005 to 0.20 wt% % and N contain from 0.0001 to 0.0040% by weight of the component,
The thickness of the metal plate is 10 ~ 100㎛,
The tensile strength of the metal plate is 300 to 700 MPa,
The elongation of the metal plate is 5 to 35%, and
A metal plate for a battery container, characterized in that the ratio of the crystal grain size in the plane direction and the thickness direction of the metal plate is 0.8 to 8 when measured in the cross section of the metal plate. According to claim 1,
A metal plate for a battery container, characterized in that it has a surface treatment layer containing Cr or Ni on the metal plate. 3. The method of claim 1 or 2,
The metal plate is a metal plate for a battery container, characterized in that it is coated with a thermoplastic resin. 4. The method of claim 3,
The thermoplastic resin is a metal plate for a battery container, characterized in that it comprises a polyolefin-based resin or a polyester resin. 5. The method of claim 4,
The said polyolefin resin or polyester resin coat|covers both surfaces of the said metal plate, The metal plate for battery containers characterized by the above-mentioned. 6. The method of claim 5,
The polyolefin-based resin covering one side of the metal plate is a polypropylene resin,
A metal plate for a battery container, characterized in that the polyester resin covering the other side of the metal plate is polyethylene terephthalate. 7. The method of claim 6,
The polyester resin is a metal plate for a battery container, characterized in that the non-oriented. 4. The method of claim 3,
The thickness of the thermoplastic resin is a metal plate for a battery container, characterized in that 10 ~ 50㎛. A method for manufacturing a metal plate for a battery container made of a metal plate of iron or iron alloy, the method comprising:
In the metal plate, C is 0.0001 to 0.1 wt%, Si is 0.001 to 0.5 wt%, Mn is 0.01 to 1.0 wt%, P is 0.001 to 0.05 wt%, S is 0.0001 to 0.02 wt%, Al is 0.0005 to 0.20 wt% % and N contain from 0.0001 to 0.0040% by weight of the component,
A first step of cold-rolling the metal plate to a thickness of 10 to 100 μm;
After the first process, there is a second process of annealing the metal plate,
The tensile strength of the metal plate is 300 to 700 MPa, the elongation of the metal plate is 5 to 35%, and the ratio of the crystal grain size in the planar direction and the thickness direction of the metal plate is 0.8 to 8 when measured from the cross section of the metal plate A method of manufacturing a metal plate for a battery container, characterized in that softening the metal plate. 10. The method of claim 9,
After the first process, before or after the second process, a third process of forming a surface treatment layer on the metal plate is included.

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