JP2007335205A - Steel sheet for forming battery can with superior leakage resistance and heavy-load discharge performance, its manufacturing method, battery can, and alkaline dry cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel sheet for forming a battery can equipped with both superior leakage resistance and heavy-load discharge performance (discharge performance after long term storage), its manufacturing method, a battery can, and an alkaline dry cell. <P>SOLUTION: This steel sheet includes: an Fe-Ni alloy plated layer or an Fe-Ni diffusion alloy layer 2 with an Fe concentration of an outermost surface layer which is a surface to be a can inner face set within the range of 10 atom% or more and 70 atom% or less; a recrystallized Ni layer 3 having a thickness of 0.2 μm or more formed therebelow; and an Fe-Ni diffusion alloy layer 4 further formed therebelow. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a steel plate for forming a battery can formed by pressing a thin steel plate plated with nickel or a nickel-iron alloy and having excellent leakage resistance and heavy load discharge performance, a manufacturing method thereof, a battery can and an alkaline battery. In particular, the present invention relates to an alkaline battery in which a strong alkaline solution having a high pH is used as a positive electrode active substance.

  As a typical example of a battery in which a strong alkaline solution having a high pH is used as the electrolytic solution, an alkaline manganese dry battery can be given. In general, a battery can is used in an alkaline battery as a container for filling a content that also serves as a positive electrode terminal. As a method of manufacturing the battery can, there are a case where a steel plate (so-called pre-plated steel plate) having a plating layer on the surface is formed and a case where post-plating (so-called glass plating) is performed after the steel plate is formed into a battery can. In the plating, mainly Ni having good alkali corrosion resistance is used. The method of plating a battery can after forming has low production efficiency and poor uniformity of the amount of plating, and in recent years, a method of forming a steel plate having a plating layer on the surface in advance has become the mainstream.

  An alkaline battery has a phenomenon in which hydrogen gas is generated in the battery as the deterioration with time progresses, and the internal pressure increases. If the internal pressure becomes too high, the gasket installed in the battery breaks and leaks, which may adversely affect electronic equipment. In recent years, when battery performance has been further improved and a longer battery life has been pursued, if this leakage resistance performance is comparable to that of conventional products, leakage can be prevented even though the battery can be used. It is thought that it will cause a situation to occur. Therefore, there has been a problem that a substantial battery life must be secured safely by greatly improving the liquid leakage resistance.

  It is important that the inner surface side of the battery can has excellent alkali corrosion resistance, the outer surface side has a beautiful luster, and excellent corrosion resistance. In addition, since the battery can serves as a positive electrode terminal as well as a container, it is important from the viewpoint of discharge performance to stably exhibit a low electric resistance.

  In order to improve the discharge performance, many investigations have been made on the filling contents, but the influence of the state of the battery can, especially the inner surface of the battery can, on the discharge performance is not clear enough. It is.

  For example, in Patent Document 1, the contact area with the conductive coating applied to the inner surface of the can body is increased by performing hard plating that causes cracking in the Ni plating layer during can body processing, and the discharge performance is improved. It is going to be improved. By forming Ni or Ni alloy plating on the surface that becomes the inner surface of the can, further heat treating them to form a diffusion alloy layer, or providing two or more plating layers or alloy layers having different hardnesses, Other conventional techniques for improving the discharge performance by sometimes causing cracks in the plating or alloy layer and increasing the contact area with the conductive paint include Patent Document 2, Patent Document 3, Patent Document 4, Patent Document 5, Techniques described in Patent Literature 6, Patent Literature 7, Patent Literature 8, Patent Literature 9, and the like are disclosed.

  As other methods for improving the battery performance, Patent Document 10, Patent Document 11 and the like are disclosed as methods for improving the discharge performance by appropriately alloying the outermost layer on the surface that becomes the inner surface of the can or by providing an alloy plating layer. The technique described in (1) is mentioned.

  However, especially with the recent development of portable electronic devices, dry batteries have high heavy-load discharge performance (discharge performance after long-term storage), that is, they can be repeatedly discharged with a large current and have a longer battery life. Is required. Conventionally, the heavy load discharge performance of a battery is generally evaluated by a continuous discharge test at a constant resistance (for example, 2Ω, 10Ω, 75Ω, etc.) or by measuring the internal resistance of the battery. However, in view of recent battery usage, it is necessary to re-evaluate the battery life by conducting a more stringent test than before. This is because even in the conventional test, even if the evaluation is equivalent, the discharge test under the heavy load condition does not always show the same level of performance, and the performance difference may be clearly manifested.

  In the conventional technology, not only the influence of the surface state of the can body on the improvement of the heavy load discharge performance is unclear, but also the leakage resistance performance, which is particularly important as the heavy load discharge performance is improved, has been studied. The current situation is not.

  An alkaline battery such as LR6 (AA) accommodates a power generating element containing an alkaline electrolyte in a bottomed cylindrical metal positive electrode can, and the opening of the positive electrode can has a metal negative terminal plate and a resin sealing gasket. It is configured with an air-tight mouth. The power generation element is formed of a positive electrode mixture formed and solidified in a tubular shape, a cylindrical separator impregnated with an alkaline electrolyte, and a gelled negative electrode mixture. The positive electrode mixture uses a metal oxide such as manganese dioxide as the positive electrode active substance, and the negative electrode mixture uses zinc as the negative electrode active substance. Electricity is generated by the discharge reaction of these two types of active substances.

  The positive electrode mixture is fitted and inserted into the positive electrode can in a press-fit state, and is accommodated in a state of being in direct contact with the positive electrode can. Thereby, a positive electrode can can serve as a positive electrode collector and a positive electrode terminal. The negative electrode terminal plate has a dish shape (or hat shape), and rod-shaped metal negative electrode electrons are erected on the inner side surface thereof, that is, the battery side surface by spot welding or the like. The current collector is penetrated into the negative electrode mixture. The gasket is formed by molding an electrically insulating resin in a substantially disk shape, and is interposed between the positive electrode can and the negative electrode terminal plate, and seals the air inside the positive electrode can.

  The positive electrode can is formed by pressing a thin steel plate mainly composed of iron. Iron is a material most suitable for the base of the positive electrode can in terms of strength and cost, and has a general property of being passivated by alkali. For this reason, in an alkaline battery using an alkaline solution as an electrolytic solution, iron is used as a main material of the positive electrode can.

  On the other hand, since the positive electrode can also serve as a positive electrode current collector and a positive electrode terminal, nickel or a nickel-iron alloy is used as described in Patent Document 12 in order to ensure stable and good conductivity and electrical contact on the surface. Plating is applied.

  Manganese dioxide used as a positive electrode active substance is a metal oxide having strong oxidizing power. This oxide causes corrosion of the steel plate substrate of the positive electrode can. Therefore, in the positive electrode can described in Patent Document 12, in order to prevent the corrosion, a nickel plating layer is formed on the steel plate before press working, and the iron exposure ratio in the outermost surface portion of the plating layer is regulated to 30% or less. is doing.

Iron, which is the main component of the steel sheet substrate, hardly corrodes even when it comes into contact with the alkaline electrolyte in the passivated region against strong alkali. However, in the vicinity where nickel which is a noble metal than iron, manganese dioxide (metal oxide) and oxygen (air) which are oxidants are present, the dissolution of iron becomes intense. When this dissolved iron ion reacts with the negative electrode active substance (zinc), gas is generated. Therefore, it is said that the iron ratio should be reduced if the leakage resistance is to be improved.
Japanese Patent Laid-Open No. 5-21044 JP-A-7-122246 Japanese Patent Laid-Open No. 7-300695 WO95 / 11527 Publication JP-A-8-138636 JP-A-8-138636 JP-A-10-172521 JP-A-10-172521 JP-A-11-102671 JP 2002-208382 A JP 2003-328158 A JP-A-6-2104

  As described above, in the conventional techniques described in Patent Documents 1 to 11, since the leakage resistance performance and the heavy load discharge performance (discharge performance after long-term storage) have not been studied, the leakage resistance performance and the heavy load discharge performance. It is unclear whether or not you are satisfied enough.

  According to the study by the present inventors, in a special use situation of a positive electrode can that also serves as a positive electrode current collector and a positive electrode terminal while containing a power generation element of an alkaline dry battery, leakage resistance performance that is a problem peculiar to the alkaline dry battery and In the case of aiming to improve heavy load discharge performance (discharge performance after long-term storage), it has been found that the prior art of Patent Document 12 is not necessarily effective in achieving the above object.

  The present invention was made in view of the problems peculiar to the alkaline dry battery as described above, and its purpose is a battery having a high level of leakage resistance and heavy load discharge performance (discharge performance after long-term storage). It is providing the steel plate for can formation, its manufacturing method, a battery can, and an alkaline dry battery.

  The present invention made to solve the above problems will be described below.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that it is effective to provide a recrystallized Ni layer on the surface that becomes the inner surface of the can in order to improve the leakage resistance performance. . Here, the “recrystallized Ni layer” refers to a soft Ni layer recrystallized by annealing the Ni plating layer. Since mutual diffusion occurs at the interface between the Ni plating layer and the steel plate during this annealing, an Fe—Ni diffusion alloy layer is formed on the steel plate side.

  The reason why the leakage resistance performance is improved by this method is not necessarily clear, but is estimated as follows.

  The present inventors have found that as the amount of Fe elution from the can increases, the amount of gas generated in the battery increases, and the leakage resistance is inferior because the leakage occurs in a short period of time. The cause of Fe elution from the can body is that the surface treatment layer such as the Ni plating layer and the alloy plating layer provided mainly on the inner surface of the can is cracked or peeled off during processing, and the steel plate surface is locally in the solution. It is thought to occur by touching. Moreover, when it has the alloy plating layer and diffusion alloy layer which contain Fe in the outermost layer of the surface used as a can inner surface, it is necessary to consider Fe elution from alloy plating or an alloy layer. By providing a soft recrystallized Ni layer on the inner surface of the can, it was possible to improve the followability of the surface treatment layer during processing and to suppress the occurrence of cracks, and to suppress Fe elution from the steel sheet, which is the main factor. As a result, the liquid leakage resistance is considered to have improved. Furthermore, the Fe—Ni diffusion alloy layer generated in the annealing process for obtaining the recrystallized Ni layer strengthened the adhesion between the steel sheet and the surface treatment layer to prevent peeling, and the hard diffusion alloy layer was cracked. It was thought that the hindrance to the progress to the steel plate also contributed to the improvement of the liquid leakage resistance.

  However, by providing a recrystallized Ni layer on the inner surface of the can, the leak-proof performance is significantly improved, but on the other hand, the problem is that the heavy load discharge performance is greatly deteriorated with time and the battery life is shortened. became. Therefore, the present inventors conducted extensive research on a method for improving heavy load discharge performance while maintaining a remarkable improvement effect of leakage resistance performance, and as a result, the outermost layer on the surface that becomes the inner surface of the can It was found that a method of providing an Fe—Ni alloy plating layer or an Fe—Ni diffusion alloy layer having an Fe concentration of 10 to 70% is effective.

  Therefore, as a result of further researches on the constituent requirements for satisfying both of these performances and manufacturing efficiently at low cost, the present inventors have completed the present invention.

  (1) The steel sheet for forming a battery can according to the present invention includes an Fe—Ni alloy plating layer or an Fe—Ni diffusion alloy layer in which the outermost layer Fe concentration on the surface that becomes the inner surface of the can is in the range of 10 atomic% to 70 atomic%. And a recrystallized Ni layer having a thickness of 0.2 μm or more formed in the lower layer, and a Fe—Ni diffusion alloy layer formed in the lower layer, leakage resistance performance and heavy load discharge performance Excellent. As shown in FIG. 3, when the thickness of the recrystallized Ni layer is in the range of 0.2 μm or more, the leakage resistance performance of the steel sheet becomes excellent. Moreover, as shown in FIG. 4, when the outermost layer Fe concentration is in the range of 10 atomic% to 70 atomic%, the heavy load discharge performance of the steel sheet becomes excellent.

  (2) The steel sheet for forming a battery can according to the present invention includes an Fe—Ni alloy plating layer or an Fe—Ni diffusion alloy layer in which the outermost layer Fe concentration on the surface serving as the inner surface of the can is in the range of 15 atomic% to 30 atomic%. And a recrystallized Ni layer having a thickness of 0.2 μm or more formed in the lower layer, and a Fe—Ni diffusion alloy layer formed in the lower layer, leakage resistance performance and heavy load discharge performance Excellent. As shown in FIG. 4, when the outermost layer Fe concentration is in the range of 10 atomic% to 70 atomic%, the heavy load discharge performance of the steel sheet is excellent. In particular, in the range where the outermost layer Fe concentration is 15 atomic% or more and 30 atomic% or less, the heavy load discharge performance of the steel sheet is further improved.

  (3) In the method for producing a steel plate for forming a battery can according to the present invention, a surface that becomes the inner surface of the can is subjected to Ni plating with a thickness of 0.3 μm or more, and then the Fe concentration is 15 atomic% or more 85 on the Ni plating layer. Fe-Ni alloy plating with a thickness of 0.1 μm or more and 0.5 μm or less at an atomic% or less is performed, followed by annealing and temper rolling, and the outermost layer Fe concentration is in the range of 10 atomic% or more and 70 atomic% or less. A Fe—Ni diffusion alloy layer and a recrystallized Ni layer having a thickness of 0.2 μm or more are formed under the Fe—Ni diffusion alloy layer. As shown in FIG. 3, when the thickness of the recrystallized Ni layer is in the range of 0.2 μm or more, the leakage resistance performance of the steel sheet becomes excellent. Moreover, as shown in FIG. 4, when the outermost layer Fe concentration is in the range of 10 atomic% to 70 atomic%, the heavy load discharge performance of the steel sheet becomes excellent.

  (4) In the method for producing a steel sheet for forming a battery can according to the present invention, a surface that becomes the inner surface of the can is subjected to Ni plating with a thickness of 0.3 μm or more, and then the thickness of 0.1 μm or more is set on the Ni plating layer. Fe plating of 4 μm or less is applied, followed by annealing and temper rolling, and an Fe—Ni diffusion alloy layer having an outermost layer Fe concentration in the range of 10 atomic% to 70 atomic%, and a thickness of 0. A recrystallized Ni layer of 2 μm or more is formed.

  (5) The method for producing a steel plate for forming a battery can according to the present invention is such that after the Ni plating having a thickness of 0.3 μm or more is applied to the surface to be the inner surface of the can, the recrystallized Ni layer having a thickness of 0.2 μm or more is annealed. Further, Fe-Ni alloy plating with a Fe concentration of 10% to 70% and a thickness of 0.1 μm to 0.5 μm is applied to the surface that becomes the inner surface of the can, and then subjected to temper rolling. To do.

  When forming the outermost layer composed of the Fe—Ni diffusion alloy layer, annealing is performed after the Fe—Ni alloy plating or the Fe plating is laminated on the Ni plating layer. When forming the outermost layer made of the Fe—Ni alloy plating layer, the Fe—Ni alloy plating layer is laminated on the recrystallized Ni layer after annealing.

  (6) The battery can of the present invention is formed by deep drawing and ironing the steel sheet for forming the battery can according to either (1) or (2), and is excellent in leakage resistance performance and heavy load discharge performance.

  The recrystallized Ni layer serving as the intermediate layer needs to be obtained by annealing after forming the Ni plating layer. When the Ni plating layer is annealed, the Ni plating layer itself is softened by recrystallization to improve leakage resistance performance, and an Fe-Ni diffusion alloy layer is formed between the Ni plating layer and the steel plate as a base material. Helps improve leakage resistance performance. When forming the Ni plating layer, it is desirable to use a matte Ni plating layer. The matte Ni plating layer has a smaller hardness in the state of plating as compared to the glossy Ni plating layer obtained by plating by adding a brightening material to the plating bath, and is easily softened by annealing. It is suitable for obtaining a soft recrystallized Ni layer. Furthermore, by forming a Fe—Ni alloy plating layer or a Fe—Ni diffusion alloy layer on the softened and recrystallized Ni plating layer and using this as the outermost layer, it is possible to improve heavy load discharge performance, High performance and heavy load discharge performance can be achieved.

  The steel plate used as a base material is not particularly limited as long as it is a steel plate having deep drawing workability and excellent ironing workability, but it is generally a low carbon aluminum killed steel plate or extremely low carbon steel plate used for battery cans. Is preferably used.

  (7) The alkaline dry battery of the present invention is made of a metal mainly composed of iron, and has a tubular shape having a metal oxide as a positive electrode active substance in a bottomed cylindrical positive electrode can also serving as a positive electrode current collector and a positive electrode terminal. The positive electrode mixture is inserted in a press-fitted state, and a power generation element is formed by filling the inside of the positive electrode mixture with a separator impregnated with an alkaline electrolyte and the negative electrode mixture, and the opening of the positive electrode can In an alkaline battery that is hermetically sealed using a negative electrode terminal plate and a resin sealing gasket, the positive electrode can is formed by processing the steel plate for forming a battery can according to either (1) or (2). It is characterized by that.

  (8) In the alkaline dry battery described in (7) above, manganese dioxide is used as the positive electrode active substance.

  ADVANTAGE OF THE INVENTION According to this invention, the steel plate for battery can formation which has liquid-proof performance and heavy load discharge performance (discharge performance after long-term storage) at a high level, its manufacturing method, a battery can, and an alkaline dry battery are provided.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings and tables.

  First, the structural requirements in the present invention will be described. As shown in FIG. 1, the outermost layer 4 on the inner surface of the can has an Fe—Ni alloy plating layer having an outermost layer Fe concentration of 10 to 70% in order to suppress deterioration of heavy load discharge performance when liquid leakage resistance is improved. Alternatively, an Fe—Ni diffusion alloy layer is necessary. The Fe concentration of the outermost layer 4 can be defined as Fe / (Fe + Ni) [atomic%] from the strength of Fe and Ni on the surface layer by Auger spectroscopic analysis. Further, the thickness of the alloy layer, the Ni layer, and the like can be obtained from a depth direction analysis by glow discharge spectroscopy (GDS) or a line analysis by EDS of a cross section of the steel sheet for forming a battery can. The difference between the diffusion alloy layer and the alloy plating layer is obtained at the same time by these analyses, and the one in which the concentration of Fe and Ni continuously changes is the diffusion alloy layer, and the one in which the step changes is an alloy. It is a plating layer.

  If the outermost layer Fe concentration is 10 atomic% or less, the effect of improving heavy load discharge performance cannot be obtained. Although the role of the alloy plating layer or diffusion alloy layer on the heavy load discharge performance improvement effect is not necessarily clear, the hydroxylation reaction of the surface layer is different from other ranges in the appropriate range where the outermost layer Fe concentration is 10 atomic% or more, and the heavy load It is thought that the increase in can surface resistance during discharge was suppressed. On the other hand, when an alloy plating layer or a diffusion alloy layer having an outermost layer Fe concentration exceeding 70 atomic% is formed, it becomes difficult to control the Fe concentration in the plating step, and the manufacturing efficiency is remarkably reduced. Is desirable. A more preferable range of the outermost layer Fe concentration is 15 to 30 atomic%, and in this range, both the leakage resistance performance and the heavy load discharge performance are particularly excellent.

  The thickness of the alloy plating layer or diffusion alloy layer constituting the outermost layer 4 is preferably 0.1 μm or more and 1.0 μm or less. If the thickness is less than 0.1 μm, it is difficult to uniformly coat, so that deterioration of heavy load discharge performance cannot be suppressed. On the other hand, when the thickness exceeds 1.0 μm, not only the production efficiency is reduced and the cost is increased, but also when the outermost layer Fe concentration of the alloy plating layer or the diffusion alloy layer is 70% or less, the layer directly touches the inner solution. This is inconvenient because the amount of Fe present increases and the amount of Fe elution increases, which adversely affects leakage resistance. In particular, when good leakage resistance is required, the thickness is more preferably 0.5 μm or less.

  It is necessary to provide a recrystallized Ni layer 3 below the outermost layer 4 made of the Fe—Ni alloy plating layer or the Fe—Ni diffusion alloy layer for the purpose of improving leakage resistance. In the process of forming, the Fe—Ni diffusion alloy layer 2 can be further provided in the lower layer. Since the Fe—Ni alloy plating layer or the Fe—Ni diffusion alloy layer that is the outermost layer 4 is relatively hard, cracks are likely to occur during can body processing. When this crack reaches the steel plate 1 (base material), the leakage resistance performance deteriorates. Therefore, by providing the recrystallized Ni layer 3 below the outermost layer 4, it is most important to improve the spreadability and suppress the generation of cracks.

  In order to obtain these effects, the thickness of the recrystallized Ni layer 3 is desirably 0.2 μm or more, and more preferably 0.5 μm or more. On the other hand, if the recrystallized Ni layer 3 becomes too thick, not only is it uneconomical, but also the outermost Fe—Ni alloy plating layer or the diffusion alloy layer 4 is peeled off during processing, and the heavy load discharge performance deteriorates. The thickness of the recrystallized Ni layer 3 is preferably 2.5 μm or less.

  Further, by providing the Fe—Ni diffusion alloy layer 2 under the recrystallized Ni layer 3, the adhesion between the steel plate 1 (base material) and the surface treatment layer is strengthened to prevent the surface treatment layer from peeling off and hard. Since the alloy layer 2 can also suppress the progress of cracks generated in the outermost layer 4 to the steel plate 1 side, an effect of promoting the effect of improving the leakage resistance performance can be obtained. The thickness of the Fe—Ni alloy layer 2 on the steel plate 1 (base material) side is preferably 0.2 μm or more. On the other hand, if the Fe—Ni diffusion alloy layer 2 is too thick, the Ni layer 3 and the alloy layer 4 are peeled off and the leakage resistance is deteriorated. Therefore, the thickness of the Fe—Ni diffusion alloy layer 2 is 1.5 μm or less. It is preferable to do this.

  Such a battery can forming steel plate 5 is subjected to Ni plating on the inner surface of the base steel plate 1 and subsequently subjected to Fe-Ni alloy plating or Fe plating, and then annealed and temper rolled. After performing Ni plating, it anneals, and after giving Fe-Ni alloy plating, it is obtained by temper rolling.

  As a steel plate as a base material, that is, a plating base plate, a low carbon aluminum killed cold rolled steel plate, a non-aging ultra low carbon steel plate to which Nb, Ti, B or the like is added alone or in combination are preferably used. Desirably, the steel sheet has low anisotropy of the Rankford value, high cleanliness and few inclusions, and good Ni plating adhesion. The anisotropy of the Rankford value (so-called Δr) is preferably 0.2 or less in absolute value. In order to reduce inclusions, the oxygen content in the steel is desirably 0.010% by weight or less, and more preferably 0.005% by weight or less. In order to ensure the uniformity of Ni plating and suppress the occurrence of unevenness and streak-like surface defects, Mn is 1.0% or less, Si is 0.1% or less, Ti is 0.05% or less, Cr is used. It is desirable that the content be 0.1% or less.

  The production method of the steel plate is not particularly problematic if it is produced according to a conventional method, and is a normal cold-rolled steel plate that has been subjected to continuous casting after component adjustment and subjected to hot rolling, pickling, cold rolling, annealing, temper rolling, or A steel sheet is used that is cold-rolled and omits annealing and temper rolling.

  Ni plating is applied to the surface which becomes the can inner surface of such a steel plate. The plating bath can be produced without any problem using either a known watt bath or a sulfamic acid bath. Subsequently, when performing Fe—Ni alloy plating, a necessary amount of iron ions may be added to these known Ni plating baths. When performing Fe plating, for example, a known ferrous sulfate-based plating solution or ferrous chloride-based plating solution may be used.

  Annealing is performed after plating to obtain a diffusion alloy layer and softening by recrystallization of the Ni plating layer. When a cold-rolled steel plate is used as a plating original plate, it can also serve as recrystallization annealing of the steel plate. The annealing method may be either batch annealing or continuous annealing, but in batch annealing, it is difficult to uniformly control the outermost layer Fe concentration and diffusion alloy layer thickness of the surface that becomes the inner surface of the can over the entire length in the coil. More preferably, continuous annealing is performed. After annealing, temper rolling is performed to temper the steel plate as a base material and adjust the roughness of the plating surface. Further, after forming the Ni plating layer, recrystallization softening may be performed by annealing, and then Fe-Ni alloy plating may be performed, followed by temper rolling.

  In addition, what is necessary is just to select suitably the structure of the plating layer formed in the surface used as a can outer surface in consideration of the beauty of appearance and corrosion resistance. For example, a bright plating layer obtained by adding a bright material to a plating bath and plating, various Ni alloy plating layers, and the like are suitable. The plating layer may be formed before annealing to obtain a recrystallized Ni layer or alloy layer on the surface that will be the inner surface of the can, or may be formed after annealing. An appropriate method for manufacturing efficiency should be selected as appropriate.

  FIG. 2 is an internal perspective sectional view showing an embodiment of an alkaline battery using the present invention. The alkaline dry battery 10 is a sealed cylindrical alkaline battery having a model number standard such as LR6 (AA type dry battery), and has a bottomed cylindrical metal positive electrode can 11 serving as a positive electrode current collector and a positive electrode terminal, alkaline electrolysis. The power generation element 20 includes a liquid, a dish-shaped (or hat-shaped) metal negative electrode terminal plate 31, a rod-shaped metal negative electrode current collector 25, an electrically insulating resin sealing gasket 35, and the like.

  The power generation element 20 includes a positive electrode mixture 21 using manganese dioxide, which is a metal oxide as a positive electrode active substance, a separator 22 impregnated with an alkaline electrolyte, and a negative electrode mixture 23 using gelled zinc as a negative electrode active substance. And formed. The positive electrode mixture 21 is formed into a tubular shape and is inserted into the positive electrode can 11 in a press-fit state. A cylindrical separator 22 is disposed inside the positive electrode mixture 21, and a gelled negative electrode mixture 23 is filled inside the separator 22. And electric power generation is performed by the discharge reaction of these two types (manganese dioxide and zinc) of the electric power generating substance.

  The positive electrode mixture 21 is housed in a state of being in direct contact with the positive electrode can 11 by being inserted into the positive electrode can 11 in a press-fitted state. Thereby, the positive electrode can 11 also serves as a positive electrode current collector and a positive electrode terminal. The negative electrode terminal plate 31 is dish-shaped (or hat-shaped), and a rod-shaped metal current collector 25 is erected on the inner side surface thereof, that is, the battery side surface by spot welding or the like. The current collector 25 is inserted into the negative electrode mixture 23.

  The gasket 35 is obtained by molding an electrically insulating resin such as nylon or polypropylene into a substantially disk shape, and is interposed between the positive electrode can 11 and the negative electrode terminal plate 31 in a pressurized state, and the inside of the positive electrode can 11 is formed. Seal. The opening of the positive electrode can 11 is bent (curled) inward. By this bending process, the peripheral portion of the gasket 35 is sandwiched between the positive electrode can 11 and the negative electrode terminal plate 31, and the inside of the positive electrode can 11 is hermetically sealed. Reference numeral 15 denotes a film-like exterior material on which decorative printing such as a label is applied. Reference numeral 39 is an insulating washer made of resin, and is interposed between the inwardly bent end of the positive electrode can 11 and the negative electrode terminal plate 31.

  The positive electrode can 11 is obtained by pressing (deep drawing) the steel plate (1) or (2) described in the problem solving means. This steel sheet has a Fe—Ni alloy plating layer or a Fe—Ni diffusion alloy layer formed on the surface portion. In this case, the Fe—Ni alloy plating layer or the Fe—Ni diffusion alloy layer is formed at least in a portion that becomes the inner surface portion of the battery. And the Fe density | concentration in the positive electrode can inner surface part 111 at least from the said opening part to the part which contact | connects the positive mix 21 is 10-70 atomic% in the stage which accommodates the said electric power generation element 20, More preferably, 15-30 atoms It is specified to be in the range of%.

  In the present invention, the Fe concentration is specified in the range of 10 to 70 atomic%, more preferably 15 to 30 atomic%, based on the above-described findings. This is because it is specifically effective in securing both the discharge performance at a high level. In this case, the Fe concentration range (10 to 70 atomic%, more preferably 15 to 30 atomic%) is defined at least in the inner surface portion from the opening of the positive electrode can 11 to the portion in contact with the positive electrode mixture 21. In addition, significant effects can be obtained in leakage resistance and discharge performance. The inner surface portion is a location where nickel, which is a noble metal than iron, manganese dioxide (metal oxide), which is an oxidizing agent, and oxygen (air) are both present, and the Fe concentration at this location is within the above range ( 10 to 70 atomic%, more preferably 15 to 30 atomic%), iron oxidation can be suppressed so that both the leakage resistance and the discharge performance after long-term storage can be secured at a high level.

  The present invention will be further described in the following examples.

  The following experiments were conducted using the ultra-low carbon steel plate and the low-carbon A1 killed steel plate after the cold rolling and annealing as they were cold-rolled with a thickness of 0.25 mm as the plating base plate. Table 1 shows the chemical composition of the steel plate.

The plating original plate was subjected to pretreatment of alkali degreasing, water washing, sulfuric acid washing and water washing by a conventional method, and then plated. The combination of plating types on the inner surface side is only for matte Ni plating, with Fe-Ni alloy plating on the upper layer of matte Ni plating, or with Fe plating on the upper layer of matte Ni plating Three types were used. As a method of Fe plating is a ferrous ammonium bath sulfate 250~360g / L, pH = 2.8~5.0, the current density at a bath temperature of 24 ° C. was 2A / dm ^2. All the surfaces on the outer surface side were subjected to bright Ni plating with a thickness of 1.5 μm. Thereafter, annealing was performed in a reducing atmosphere in the range of 600 ° C. to 820 ° C. for 30 seconds to 300 seconds to recrystallize and soften the matte Ni plating layer. In this case, annealing may be performed in a non-oxidizing atmosphere. Further, a portion of the inner surface provided with only the matte Ni plating layer was subjected to Fe—Ni alloy plating after annealing. After temper rolling these steel sheets, battery cans were prepared.

  In addition, for comparison, an ultra-low carbon steel sheet after cold rolling, annealing, and temper rolling is used as a plating base plate, matte Ni plating is applied to the inner surface, and bright Ni plating is applied to the outer surface. A general Ni-plated steel sheet not subjected to annealing and temper rolling, or only a Fe—Ni alloy plating layer not provided with a recrystallized Ni layer was also produced to produce a battery can.

  As a method for forming the battery can, a method combining deep drawing and ironing can be selected as appropriate. After forming the squeezing cup, DI molding that performs ironing, after forming the squeezing cup, after drawing and bending and bending back, stretching draw by adding ironing if necessary, after several stages of drawing It may be processed by any method such as multi-stage drawing with ironing.

  In this example, an LR-6 (AA) type battery can (positive electrode can) 11 shown in FIG. 2 was formed by multistage drawing using the battery can forming steel plate 5 shown in FIG. Using these battery cans 11, alkaline manganese dry batteries were produced, and each of leakage resistance performance and heavy load discharge performance was evaluated.

  Table 2 shows the details of the surface-treated layer structure of the surface on the inner surface side of the surface-treated steel sheet before forming the battery can 11. The thickness of each layer was determined by performing cross-sectional polishing of the surface-treated steel sheet and observing it with an SEM, and performing an EDS thickness direction line analysis with EDS. The Fe concentration of the outermost layer was determined by Auger spectroscopic analysis, after sputtering for 30 seconds with Ar in order to eliminate the influence of adsorbed elements, the strength of Fe and Ni on the surface layer was measured, and Fe / (Fe + Ni) [atomic%] As sought.

  Liquid leakage resistance performance is maintained at 90 ° C for the manufactured alkaline manganese battery, checked for liquid leakage every 24 hours, measured for the number of days that liquid leakage occurred until leakage occurred, and the measurement days were leaked. It investigated using the evaluation method made into a liquid lifetime. The liquid leakage life of Comparative Example 1, which is a general Ni-plated steel sheet, is assumed to be 100% (reference value), and the results of calculating the respective liquid leakage lifetimes are also shown in Table 2 as leakage resistance performance. In the table, leakage resistance performance of 150% or more, that is, 1.5 times or more of Comparative Example 1 and markedly improved is indicated by double circles, and those of 100% or more and less than 150% are indicated by circles.

  The heavy load discharge performance (discharge performance after long-term storage) is not an evaluation method with a constant resistance that has been generally used in the past, but an alkaline manganese dry battery at After keeping the temperature constant for a day, a 1500 mA continuous discharge test was performed, the time until the voltage became 0.9 V or less was measured, and the measurement time was used as an evaluation method. This method is more heavily loaded than the conventional discharge test method. The discharge life of Comparative Example 1, which is a general Ni-plated steel sheet, is assumed to be 100%, and the results of calculating the respective discharge life are also shown in Table 2 as heavy load discharge performance. In the table, heavy load discharge performance is 100% or more and less than 115% and the same or better than Comparative Example 1 is indicated by a circle, and 115% or more and improved by 15% or more than Comparative Example 1 is indicated by a double circle. displayed.

  In addition, as a comprehensive evaluation, those having leakage resistance performance of 150% or more and discharge performance of 100% or more and less than 115%, or those having leakage resistance performance of 100% or more and less than 150% and heavy load discharge performance of 115% or more are round. Displayed with a double circle to indicate that the leakage resistance performance is 150% or more and the heavy load discharge performance is 115% or more, and either the leakage resistance performance or the heavy load discharge performance is less than 100% Was displayed.

  FIG. 3 shows the result of examining the relationship between the thickness (μm) of the recrystallized Ni layer on the inner surface side and the leakage resistance performance (%). The results of examining the relationship with the load discharge performance (%) are shown in FIG.

  As is apparent from FIG. 3, the leakage-proof performance is improved by providing a recrystallized Ni layer having a thickness of 0.2 μm or more, and is particularly improved by setting the thickness of the recrystallized Ni layer to 0.5 μm or more. Can be made. Further, as apparent from FIG. 4, when the outermost layer Fe concentration is in the range of 10 to 70%, the heavy load discharge characteristics equal to or higher than those of Comparative Example 1 which is a general Ni-plated steel sheet are maintained, and leakage resistance is maintained. Liquid performance can be improved.

  In particular, as is apparent from FIG. 4, when the outermost layer Fe concentration is in the range of 15 to 30%, the heavy load discharge characteristics can be improved by 15% or more, and the leakage resistance can be improved.

As a result of the above evaluation, Examples 1 to 12 and Comparative Examples 2, 5, and 6 in which the recrystallized Ni layer was formed were excellent in liquid leakage resistance. In particular, Examples 2 to 5 had leakage resistance performance of 150% or more and heavy load discharge performance of 115% or more, and both characteristics were particularly excellent. On the other hand, Comparative Example 2 having no Fe—Ni alloy plating layer or diffusion alloy layer in the outermost layer was significantly inferior in heavy load discharge performance. Further, Comparative Example 5 in which the outermost layer Fe concentration was less than 10% and Comparative Example 6 in which the thickness of the recrystallized Ni layer exceeded 2.5 μm were inferior in heavy load discharge performance. Further, Comparative Examples 3 and 4 in which the recrystallized Ni layer was not provided had poor leakage resistance performance.

  The steel sheet for forming a battery can of the present invention is used for a battery can such as an alkaline manganese battery filled with a strong alkaline solution having a high pH as an electrolyte.

The schematic sectional drawing which shows typically the site | part used as the can inner surface side of the steel plate for battery can formation. The schematic sectional drawing which shows an alkaline dry battery. The characteristic line figure which shows the relationship between outermost layer Fe density | concentration of a can inner surface, and leak-proof performance. The characteristic diagram which shows the relationship between the outermost layer Fe density | concentration of a can inner surface, and heavy load discharge performance.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Steel plate 2 ... Fe-Ni diffusion alloy layer 3 ... Recrystallized Ni layer 4 ... Fe-Ni alloy plating layer or Fe-Ni diffusion alloy layer (outermost layer)
5 ... Steel plate for battery can formation (surface on the inner surface of the can)
10 ... Alkaline battery 11 ... Battery can (positive electrode can)
DESCRIPTION OF SYMBOLS 15 ... Exterior material 21 ... Positive electrode mixture 22 ... Separator 23 ... Negative electrode mixture 25 ... Negative electrode current collector 31 ... Negative electrode terminal board 35 ... Gasket 39 ... Insulating washer

Claims (8)

 Fe-Ni alloy plating layer or Fe-Ni diffusion alloy layer in which the outermost layer Fe concentration on the surface that becomes the inner surface of the can is in the range of 10 atomic% to 70 atomic%, and a thickness of 0.2 μm or more formed in the lower layer A steel sheet for forming a battery can having excellent leakage resistance and heavy load discharge performance, comprising: a recrystallized Ni layer; and a Fe—Ni diffusion alloy layer formed thereunder.  Fe-Ni alloy plating layer or Fe-Ni diffusion alloy layer in which the outermost layer Fe concentration on the surface which becomes the inner surface of the can is in the range of 15 atomic% or more and 30 atomic% or less, and a thickness of 0.2 μm or more formed in the lower layer A steel sheet for forming a battery can having excellent leakage resistance and heavy load discharge performance, comprising: a recrystallized Ni layer; and a Fe—Ni diffusion alloy layer formed thereunder.  The inner surface of the can is Ni-plated with a thickness of 0.3 μm or more, and then the Fe concentration is 15 atomic% to 85 atomic% on the Ni plating layer and the thickness is 0.1 μm to 1.0 μm. -Ni alloy plating is performed, and then annealing and temper rolling are performed, and the Fe-Ni diffusion alloy layer having an outermost layer Fe concentration in the range of 10 atomic% to 70 atomic% and a thickness of 0.2 μm below the Fe-Ni diffusion alloy layer A method for producing a steel plate for forming a battery can excellent in leakage resistance and heavy load discharge performance, characterized by forming the above recrystallized Ni layer.  Ni plating with a thickness of 0.3 μm or more is applied to the inner surface of the can, then Fe plating with a thickness of 0.1 μm to 0.4 μm is applied on the Ni plating layer, and then annealing and temper rolling are performed. An Fe—Ni diffusion alloy layer having an outermost layer Fe concentration in the range of 10 atomic% to 70 atomic% and a recrystallized Ni layer having a thickness of 0.2 μm or more under the Fe—Ni diffusion alloy layer, A method for producing a steel plate for forming a battery can having excellent leakage resistance and heavy load discharge performance.   After Ni plating having a thickness of 0.3 μm or more is applied to the surface that becomes the inner surface of the can, a recrystallized Ni layer having a thickness of 0.2 μm or more is formed by annealing, and the Fe concentration is 10% on the surface that becomes the inner surface of the can Featuring an Fe-Ni alloy plating with a thickness of 0.1 μm or more and 0.5 μm or less at 70% or less, followed by temper rolling, forming a battery can excellent in leakage resistance and heavy load discharge performance Steel plate manufacturing method.   A battery can excellent in leakage resistance and heavy load discharge performance, wherein the battery can forming steel sheet according to claim 1 is deep-drawn and ironed.  A tubular positive electrode mixture having a metal oxide as a positive electrode active material is inserted in a press-fit state into a bottomed cylindrical positive electrode can made of a metal mainly composed of iron and also serving as a positive electrode current collector and a positive electrode terminal. In addition, a power generation element is formed by filling the inside of the positive electrode mixture with a separator impregnated with an alkaline electrolyte and a negative electrode mixture, and the opening of the positive electrode can uses a negative electrode terminal plate and a resin sealing gasket. An alkaline battery, wherein the positive electrode can is formed by processing the steel sheet for forming a battery can according to claim 1. 8. The alkaline dry battery according to claim 7, wherein manganese dioxide is used as the positive electrode active substance.

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