JP2012104452A - Positive electrode can for alkaline battery, method for manufacturing the same, and alkaline battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a positive electrode can for an alkaline battery securely preventing the alkaline battery from leaking.SOLUTION: The positive electrode can 11 for an alkaline battery 10 is a cylindrical pressed component having an opening 16, a trunk 17, and a bottom 18. The trunk 17 is supplied with a positive electrode mixture 12 under pressure, and the opening 16 is equipped with a sealing gasket 23. The positive electrode can 11 is manufactured by pressing so that the surface roughness of the portion of a steel sheet before pressing to form the inner surface of the positive electrode can 11 is greater than the surface roughness of the inner surface of the positive electrode can 11 after pressing. The surface roughness Ra of the steel sheet before pressing is 1.5 to 3.0 μm, and the surface roughness Ra of the inner surface of the positive electrode can 11 after pressing is 1.0 to 2.5 μm.

Description

  The present invention relates to a method for producing a positive electrode can for an alkaline battery in which a bottomed cylindrical positive electrode can is manufactured by pressing a steel plate, a positive electrode can for an alkaline battery, and an alkaline battery configured using the positive electrode can. .

  Generally, an alkaline battery includes a bottomed cylindrical positive electrode can, a ring-shaped positive electrode mixture housed in the positive electrode can, a gel-like negative electrode mixture disposed in the center of the positive electrode can, and a positive electrode mixture. And a gelled negative electrode mixture, and a bottomed cylindrical separator, and a current collector attached to the opening of the positive electrode can. The current collector includes a negative terminal plate, a sealing plate, and a sealing gasket. Moreover, the positive electrode can of an alkaline battery is produced by press-molding a nickel-plated steel sheet into a bottomed cylindrical shape. The positive electrode mixture is prepared by adjusting the positive electrode mixture powder mainly composed of manganese dioxide or nickel oxyhydroxide and then press-molding it into a cylindrical shape, and is press-fitted inside the positive electrode can.

  In the conventional alkaline battery, the inner surface of the positive electrode can is roughened during press processing, the adhesion between the positive electrode can and the positive electrode mixture is improved, and the discharge performance is improved. Patent Document 1 discloses manufacturing a positive electrode can for an alkaline battery using a surface-treated steel sheet having a surface roughness Ra of 0.8 μm to 2 μm.

JP-A-11-111243

  By the way, when the surface roughness of the inner surface is increased when pressing the positive electrode can, the nickel plating on the surface may be broken, and the underlying iron may be partially exposed. In this case, during long-term storage, the iron base of the positive electrode can is corroded by the alkaline electrolyte, and gas is generated in the battery. As the gas is generated, the internal pressure of the battery rises and the safety valve provided in the sealing gasket is operated, which may cause liquid leakage.

  This invention is made | formed in view of said subject, The objective is to provide the manufacturing method of the positive electrode can for alkaline batteries which can prevent the leakage of an alkaline battery reliably. Another object of the present invention is to provide a positive electrode can for alkaline batteries and an alkaline battery that are excellent in leakage resistance and have high reliability.

  Means [1] to [5] for solving the above problems are listed below.

  [1] A method for producing a bottomed cylindrical positive electrode can for an alkaline battery by pressing a steel plate, wherein the surface roughness of the portion that becomes the inner surface of the positive electrode can in the steel plate before press processing is after the press processing A method for producing a positive electrode can for alkaline batteries, wherein the press working is performed so as to be larger than the surface roughness of the inner surface of the positive electrode can.

  According to the invention described in Means 1, when forming the positive electrode can by press working, the inner surface of the positive electrode can is smoothed by a multistage drawing of a steel plate having a relatively large surface roughness. If it does in this way, exposure of an iron base will decrease and it will become difficult to corrode a positive electrode can to alkaline electrolyte. As a result, when the battery is stored for a long time, the gas generated in the battery can be suppressed, and the leakage resistance performance of the positive electrode can is improved.

  [2] A method for producing a positive electrode can for an alkaline battery, characterized in that in the means 1, the surface roughness Ra of the steel sheet before press working is 1.5 μm or more and 3.0 μm or less.

  According to the invention described in Means 2, by making the surface roughness Ra of the steel sheet 1.5 μm or more and 3.0 μm or less, a positive electrode can having a surface roughness excellent in leakage resistance performance after press working can be produced. it can.

  [3] A method for producing a positive electrode can for an alkaline battery, characterized in that, in the means 1 or 2, the surface roughness Ra of the inner surface of the positive electrode can after press working is 1.0 μm or more and 2.5 μm or less.

  According to the invention described in the means 3, by adjusting the surface roughness Ra of the inner surface of the positive electrode can after the press working to 1.0 μm or more and 2.5 μm or less, the exposure of the iron base is reduced, and the gas generated in the battery It can be surely reduced.

  [4] A positive electrode can for an alkaline battery manufactured using the manufacturing method according to any one of means 1 to 3.

  According to the invention described in the means 4, the leakage resistance performance of the positive electrode can can be improved.

  [5] An alkaline battery configured using the positive electrode can according to means 4.

  According to the invention described in means 5, the leakage resistance performance of the alkaline battery can be improved.

  As described above in detail, according to the inventions described in the means 1 to 3, it is possible to provide a method for producing a positive electrode can for an alkaline battery that can reliably prevent leakage of the alkaline battery. In addition, according to the invention described in the means 4, it is possible to provide a positive electrode can for an alkaline battery that has excellent liquid leakage resistance and high reliability. Furthermore, according to the invention described in the means 5, it is possible to provide an alkaline battery that is excellent in leakage resistance and highly reliable.

Sectional drawing which shows the alkaline battery of one Embodiment.

  Hereinafter, an embodiment in which the present invention is embodied in an alkaline battery will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of an alkaline battery 10 in the present embodiment. In addition, the alkaline battery 10 of the present embodiment is an LR6 type (AA) battery.

  As shown in FIG. 1, the alkaline battery 10 includes a bottomed cylindrical positive electrode can 11, a ring-shaped positive electrode mixture 12, a bottomed cylindrical separator 13, a gelled negative electrode mixture 14, The electric body 15 is provided. In the alkaline battery 10, the positive electrode mixture 12 is fitted along the inner surface of the positive electrode can 11, and a separator 13 is inserted inside the positive electrode mixture 12. The gelled negative electrode mixture 14 is disposed in the hollow portion of the separator 13 that is the central portion of the positive electrode can 11.

  The positive electrode can 11 is a press-processed product made of a nickel-plated steel plate, and is press-formed into a bottomed cylindrical shape having an opening 16, a body portion 17, and a bottom portion 18. The positive electrode mixture 12 is pressed into the body portion 17 of the positive electrode can 11, and the current collector 15 is attached to the opening 16. Further, a positive electrode terminal 19 protrudes from the center of the bottom 18 of the positive electrode can 11.

  The separator 13 is produced by winding separator base paper such as vinylon / rayon non-woven fabric or polyolefin / rayon non-woven fabric in a cylindrical shape and heat-sealing the overlapping portions. The gelled negative electrode mixture 14 is produced by mixing water, zinc oxide and potassium hydroxide and dissolving them, and mixing a gelling agent such as polyacrylic acid and zinc powder.

  The current collector 15 includes a negative electrode terminal plate 21, a negative electrode current collector 22, and a sealing gasket 23. Near the opening 16 of the positive electrode can 11, a bead portion 24 for mounting the current collector 15 is formed. The positive electrode can 11 is sealed by curling and drawing the opening 16 of the positive electrode can 11 with the current collector 15 placed on the bead portion 24.

  The current collector 15 has a negative electrode current collector 22 formed in the shape of a rod using brass and resistance-welded to the negative electrode terminal plate 21 at the proximal end thereof, and a sealing gasket 23 is fitted to the neck of the negative electrode current collector 22. It is formed by wearing. The tip side of the negative electrode current collector 22 is inserted into the gelled negative electrode mixture 14. The negative electrode terminal plate 21 is produced by press-molding a nickel-plated steel plate like the positive electrode can 11, and seals the opening 16 of the positive electrode can 11 through a sealing gasket 23.

  The sealing gasket 23 is a resin molded product that is injection-molded using a resin material. Polypropylene resin is suitable as a material for forming the sealing gasket 23, and polyamide resin such as 6,12 nylon resin, 6,10 nylon resin, and 6,6 nylon resin may be used.

  The sealing gasket 23 of the present embodiment includes a boss portion 31 through which the negative electrode current collector 22 is inserted, a can contact portion 32 that is fixed in contact with the inner peripheral surface of the positive electrode can 11, and a contact between the boss portion 31 and the can. And a disk-shaped portion 33 provided so as to extend in the radial direction from the outer peripheral surface of the boss portion 31 in order to connect the portion 32. In addition, an annular thin portion 34 that functions as a safety valve is provided at a connection portion between the boss portion 31 and the disk-shaped portion 33 in the sealing gasket 23. In the alkaline battery 10, when the internal pressure increases due to the generation of gas, the annular thin portion 34 of the sealing gasket 23 is broken by the pressure increase to release the gas to the outside.

  Next, the manufacturing method of the positive electrode can 11 will be described in detail.

  First, a steel plate having a thickness of 0.25 mm and having a surface roughness Ra of 1.5 μm or more and 3.0 μm or less on the surface serving as the inner surface of the positive electrode can 11 is prepared. And the nickel plating is given with respect to the surface of the steel plate, and the nickel plating steel plate which has a nickel plating layer of thickness about 1 micrometer-2 micrometers is produced. Thereafter, by performing deep drawing (multi-stage drawing) step by step using a nickel-plated steel plate, the bottomed cylindrical positive electrode can 11 having a thickness of the opening 16 and the body portion 17 of 0.2 mm is pressed. Mold. In this Embodiment, the inner surface of the trunk | drum 17 is formed more smoothly than the steel plate before a process so that surface roughness Ra may be in the range of 1 micrometer-2.5 micrometers by multistage drawing. Further, the surface roughness Ra of the outer surface of the positive electrode terminal 19 protruding from the bottom 18 is 1.5 μm or more and 3.0 μm or less, which is the same roughness as the surface roughness Ra of the steel plate before processing. That is, the surface roughness of the outer surface of the positive electrode terminal 19 is larger than that of the inner surface of the body portion 17.

Further, a conductive paint is applied to the inner surface of the body portion 17 of the positive electrode can 11 so that the contact resistance with the positive electrode mixture 12 is kept low. In the positive electrode can 11, a sealing agent 25 is applied to the inner surface of the opening 16 to which the sealing gasket 23 is attached. In the present embodiment, a sealing agent containing asphalt and polybutene is used as the sealing agent 25. As described above, the sealing agent 25 is interposed between the opening 16 of the positive electrode can 11 and the sealing gasket 23, so that the adhesion is increased, and the electrolyte creeps between the positive electrode creep (the positive electrode can 11 and the sealing gasket 23. Leakage due to phenomenon is prevented.
[Example]

In this example, 13 types of LR6 type (AA) alkaline battery 10 samples prepared by the above manufacturing method were prepared, and the tests shown in Table 1 were performed on these samples. The test results are shown in Table 2.

  Specifically, in the evaluation test of the discharge performance, after the alkaline battery 10 was stored at 60 ° C. for 20 days, the discharge was repeated in a discharge mode of 1000 mA for 10 seconds per minute and 1 hour per day, and the final voltage was The performance up to 0.9 V (the number of cycles in the discharge mode) was confirmed. The test criterion is “◯” when a discharge of 360 cycles or more is performed, “Δ” when a discharge of 300 cycles or more and less than 360 cycles is performed, and “×” for a discharge of less than 300 cycles. "

  Further, in the evaluation test for leakage resistance, each alkaline battery 10 is stored at a temperature of 60 ° C. and a humidity of 90%. The test criterion is “◯” when there is no leakage due to safety valve operation after 100 days of testing, “Δ” when there is leakage during the test period of 80 days or more and less than 100 days, 80 If there is a leak in less than a day, it is marked as “x”.

  As shown in Table 2, in Samples 1 to 7, the surface roughness Ra of the steel plate before press working was changed in the range of 1.0 μm to 4.0, and the can body portion after press working (of the positive electrode can 11). The surface roughness Ra of the inner surface of the trunk portion 17) is changed in the range of 0.5 μm to 3 μm. Further, in Samples 1 to 7, the surface roughness of the steel plate is larger than the surface roughness of the can barrel portion 17.

  In Samples 8 to 13, the surface roughness Ra of the steel plate and the surface roughness Ra of the inner surface of the can body portion 17 are changed in the range of 0.5 μm to 4.0. In Samples 8 and 10 to 13, the surface roughness of the steel plate is equal to the surface roughness of the can barrel portion 17, and in Sample 9, the surface roughness of the steel plate is smaller than the surface roughness of the can barrel portion 17. It has become.

  In the case where the surface of the can body portion 17 is not made smoother than the surface of the steel plate as in Samples 8 to 13, the leakage resistance performance is deteriorated. On the other hand, it was confirmed that when the inner surface of the can body portion 17 is made smoother than the surface of the steel plate as in samples 1 to 7, the leakage resistance performance is improved.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) In the alkaline battery 10 of the present embodiment, when the positive electrode can 11 is formed by pressing, a steel plate having a relatively large surface roughness is ironed to smooth the inner surface of the positive electrode can 11. If it does in this way, exposure of an iron substrate will decrease and it will become difficult to corrode the positive electrode can 11 with respect to alkaline electrolyte. In the prior art, since the inner surface of the positive electrode can 11 is roughened by pressing, it is necessary to form a thick nickel plating layer (for example, with a thickness of 3 μm or more) on the surface of the steel sheet in order to improve corrosion resistance. On the other hand, if the inner surface of the positive electrode can 11 is made smooth as in the present embodiment, the corrosion resistance can be improved without increasing the thickness of the nickel plating layer. As a result, when the alkaline battery 10 is stored for a long time, the gas generated in the battery can be suppressed, and the liquid leakage resistance of the positive electrode can 11 is improved. Moreover, since the nickel plating layer of the nickel-plated steel sheet can be thinned to about 1 μm to 2 μm, the manufacturing cost of the positive electrode can 11 can be suppressed.

  (2) In the alkaline battery 10 of the present embodiment, the surface roughness Ra of the steel sheet before processing is 1.5 μm or more and 3.0 μm or less, and the surface roughness Ra of the inner surface of the positive electrode can 11 is 1.0 μm after press working. This is 2.5 μm or less (Samples 2 to 6). If it does in this way, discharge performance and leak-proof performance can fully be secured, and the alkaline battery 10 with high reliability can be manufactured.

  (3) In the alkaline battery 10 of the present embodiment, the surface roughness of the outer surface of the positive electrode terminal 19 protruding from the bottom 18 of the positive electrode can 11 is larger than the surface roughness of the inner surface of the positive electrode can 11. By roughening the outer surface of the positive electrode terminal 19 in this way, the contact area between the positive electrode terminal 19 and the external device is increased, and the discharge performance of the alkaline battery 10 can be sufficiently ensured.

  In addition, you may change embodiment of this invention as follows.

  In the above embodiment, the positive electrode can 11 is formed using a nickel-plated steel sheet, but a steel sheet in which a Fe—Ni diffusion layer is formed at the interface between the underlying iron and the plated layer by heat-treating the nickel-plated steel sheet. The positive electrode can 11 may be formed using If it does in this way, the corrosion resistance of the positive electrode can 11 can be improved more.

  In the above embodiment, the alkaline battery 10 of the LR6 type (AA type) is embodied, but other than the LR20 type (AAA type), LR14 type (AA type 2), LR03 type (AAA type), etc. It may be embodied in the battery.

  Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the embodiments described above are listed below.

  (1) In any one of the means 1 to 3, the positive electrode after processing rather than the surface of the steel plate before processing by performing press processing after nickel plating on the steel plate before press processing A method for producing a positive electrode can for an alkaline battery, characterized in that the inner surface of the can is smoothed.

  (2) The alkaline battery according to (5), wherein the surface roughness of the outer surface of the positive electrode terminal projecting from the bottom of the positive electrode can is larger than the surface roughness of the inner surface of the positive electrode can.

DESCRIPTION OF SYMBOLS 10 ... Alkaline battery 11 ... Positive electrode can 12 ... Positive electrode mixture

Claims (5)

A method of manufacturing a bottomed cylindrical alkaline battery positive electrode can by pressing a steel plate,
Alkaline battery characterized by performing pressing so that the surface roughness of the inner surface of the positive electrode can in the steel plate before press processing is larger than the surface roughness of the inner surface of the positive electrode can after pressing. For manufacturing positive electrode cans.   2. The method for producing a positive electrode can for an alkaline battery according to claim 1, wherein a surface roughness Ra of the steel plate before press working is 1.5 μm or more and 3.0 μm or less.   3. The method for producing a positive electrode can for an alkaline battery according to claim 1, wherein the surface roughness Ra of the inner surface of the positive electrode can after press working is 1.0 μm or more and 2.5 μm or less.   The positive electrode can for alkaline batteries manufactured using the manufacturing method of any one of Claims 1 thru | or 3.   The alkaline battery comprised using the positive electrode can of Claim 4.

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