Title of Invention

"A MANUFACTURING METHOD OF THE PLATED STEEL SHEET FOR BATTERY CONTAINERS"

Abstract

[object] The object of the present invention is to provide a plated steel sheet for battery containers that enables a battery to have excellent short-circuit current and electricity discharge characteristic, which are important characteristics of a battery performance, to provide a manufacturing method therefor, and to provide a battery container produced from the above-mentioned plated steel sheet, and a battery employing the above-mentioned battery container. [Means of Solution] A steel sheet is degreased and pickled, or a steel sheet is plated with nickel, which is further heat treated and temper rolled, and subsequently is subjected to either anodic treatment, or cathodic treatment after anodic treatment, or cathodic treatment after anodic treatment in acid solution so as to provide minute ruggedness on the nickel plating surface layer of the plated steel sheet.

Full Text

The present invention relates to a manufacturing method of a plated steel sheet for battery containers. This invention also relates to a plated steel sheet for battery containers in which alkaline solutions are filled, a manufacturing method therefor, and a battery container employing the above-mentioned plated steel sheet and a battery employing the above-mentioned battery ontainer. More specifically, this invention relates to a plated steel sheet suitable for battery containers such as used for alkali-manganese cells or nickel-cadmium batteries which are required to undergo a severe forming such as Drawing and Ironing (hereinafter referred to as DI forming), or Drawing and Stretching (hereinafter referred to as DS forming) . This invention relates to also a manufacturing method of the above-mentioned plated steel sheet, and a battery container employing this plated steel sheet and a battery employing this battery container. [ Prior technology ] In recent years, there has been used containers for batteries such as alkali-manganese cells and nickel-cadmium batteries in which strong alkaline solutions are filled. These containers are manufactured by the methods in which deep drawing is applied to form a cold rolled steel sheet into a battery container body, which is then barrel-plated with nickel, or deep drawing is applied to a nickel plated steel sheet to form a battery container body. The main reason for using the nickel plated steel sheet as a material for such battery containers is that nickel has an excellent corrosion-resistance against strong- alkali electrolyte solution because the above-mentioned batteries chiefly use strong-alkali potassium hydroxide as the electrolyte solution. The second reason is that nickel has a steady contact resistance, which is important when the battery is connected to the external terminal. Further, nickel is suitable for spot welding which is one of the battery manufacturing processes when the components are welded to be assembled into a battery. Recently, the nickel barrel-plating method in which deep drawing is applied to form a cold rolled steel strip into a battery container body, which is then barrel-plated with nickel, has been replaced with the other method in which a nickel plated steel sheet is "" eep drawn to form a battery container body. Because it is difficult to attain a uniform plating thickness, especially the thickness of the nickel plating layer applied to the inside surface of the battery container, thus hardly providing high quality products constantly. In the most recent application of the nickel-plated steel sheet, after plated with nickel, the steel sheet undergoes a thermal diffusion treatment in order to further improve the corrosion resistance. As for the relationship between the performance of alkali-manganese cell and the positive electrode, the features of the inside surface of the positive electrode case supposedly correlate with the performance of alkali-manganese cell. To be precise, the lower the contact resistance between a positive electrode case and a positive electrode mixture of an alkali-manganese cell, the higher performance the cell has. (the positive electrode mixture consisting of manganese dioxide as positive electrode active material, graphite as conductive agent, and potassium hydroxide as electrolyte.) In the case of alkali-manganese cells, the positive electrode mixture and the positive electrode case are in contact with each other, wherein the positive electrode case serves not only as a container for battery but also as a conductor which transfers electrons. Therefore, when the contact resistance between the positive electrode mixture and the inside surface of the positive electrode case is large, the internal resistance of the cell increases to thereby reduce its operation voltage, or reduce its electrical discharge duration, which could deteriorate the battery performance strikingly. So, with a view to decreasing the contact resistance between positive electrode mixture and positive electrode case, various methods have been proposed: method of increasing surface roughness of the inside surface of the positive electrode case; method of providing grooves vertically on the positive electrode case; or method of spreading the inside surface of the positive electrode case with a conductive paint or a conductive agent prepared from graphite plus binder. On the other hand, in view of increasing a battery capacity while reducing material cost at the same time by making thinner the body wall of battery container, DI forming method has been applied for producing battery containers (Japanese Patent Publication Hei 7-99686), instead of multi-step deep drawing method. According to DI forming method, a battery container can be provided with a thinner body wall than the bottom portion so that it can be charged with more positive and negative electrode materials, thus increasing the battery capacity. Additionally, this method allows the battery container to have improved pressure resisting strength because of its thicker bottom portion. From the similar viewpoint as above, a manufacturing method in which DS forming is applied after deep drawing for obtaining a battery case has been developed recently. However, the manufacturing method using DI forming or DS forming involves a disadvantage of deficiency of the adhesion between the inside surface of the battery container and the positive electrode mixture in an alkali-manganese cell or a nickel-cadmium battery, since, according to these methods, the inside surface of the battery conyainer is finished much smoother compared to the multi-step deep drawing method. Especially today, alkali-manganese cells or nickel-cadmium batteries having improved adhesion between battery container or positive electrode case and positive electrode mixture are demanded. For the cells of new type are required to be not only suitable for long time use but also have a long lifetime, and be excellent in poly addition electrical discharge. [ Problem to be solved by the Invention ] As described above, whichever method may be selected from the methods of multi-step deep drawing, DI forming, and DS forming, to manufacture a container of alkaline-manganese cell or nickel-cadmium battery, the cell or the battery needs to have a long lifetime and an excellent property in the poly addition electrical discharge. However, the alkali-manganese cell or the nickel-cadmium battery that uses the battery-container material obtained by the conventional methods has not been always satisfying the above requirement. Therefore, it is an object of the present invention to provide a plated steel sheet for battery containers having a sufficient short-circuit current property and an excellent electrical discharge characteristic, which are important essence for the battery performance, by improving the contact condition between the battery container as the positive electrode case and the positive electrode mixture. It is also the object of the present invention to provide a manufacturing method for the plated steel sheet for battery containers, and a battery container employing the above-mentioned plated steel sheet and a battery employing the above-mentioned battery container. [Means for solving the Problem] The present invention includes a plated steel sheet for battery containers which has a nickel plating surface layer that is subjected to an electrolytic treatment in an acid solution to be surface-roughened. The present invention also includes a plated steel sheet for battery containers which has a nickel plating surface layer and/or a nickel-iron alloy surface layer that is formed by applying the above mentioned nickel plating surface layer to a heat treatment and is subsequently subjected to an electrolytic treatment in an acid solution to be surface-roughened. These plated steel sheets are characterized in that one nickel plating layer applied to one side of the steel sheet has a thickness of 0.5-5 µ m and the other nickel plating layer applied to the other side of the steel sheet has a thickness of not more than 5 µ m. According to the present invention there is provided a manufacturing method of a plated steel sheet for battery containers characterized in that: degreasing or degreasing plus pickling the steel sheet; thereafter plating the steel sheet with nickel; and subsequently applying to the nickel plated steel sheet either an anodic treatment, or an anodic treatment after cathodic treatment, or a cathodic treatment after anodic treatment, in the acid solution of 1-10 percent density by weight. solution of 1-10 percent density by weight. The present invention furthermore includes a manufacturing method of the plated steel sheet for battery containers, which is characterized by the steps of: degreasing or degreasing plus pickling the steel sheet; thereafter plating the steel sheet with nickel; subsequently heat treating the nickel plated steel sheet in a non-oxidation atmosphere; applying temper rolling to the heat treated nickel-plated steel sheet; and applying to the same either an anodic treatment, or an anodic treatment after cathodic treatment, or a cathodic treatment after anodic treatment in the acid solution of 1-10 percent density by weight. These manufacturing methods are characterized in that the above-mentioned electrolysis treatment in the acid solution is either an anodic treatment, or an anodic treatment after cathodic treatment, or a cathodic treatment after anodic treatment in sulfuric acid solution or in hydrochloric acid solution or in the mixed solution of the sulfuric acid solution and the hydrochloric acid solution, and characterized in that the acid solution is sulfuric acid solution or hydrochloric acid solution or the mixed solution thereof. The present invention still further includes a battery container produced by forming the above-mentioned plated steel sheet for battery containers into a cylindrical body having a bottom portion, which is characterized in that the above-mentioned battery container has its inside surface spread with graphite. The present invention furthermore includes a battery employing the above-mentioned battery container which is packed with a negative electrode rod, a positive electrode mixture, and a negative electrode gel. [ Embodiment of the invention ] Various studies have been made to improve the battery performance of alkali-manganese cell or nickel-cadmium battery. As a result, it was found that an alkali-manganese cell or a nickel-cadmium battery employing a battery container produced from a steel sheet as a base, which was first degreased, or degreased plus pickled, then plated with a nickel layer, and subjected to a heat-treatment in a non-oxidation atmosphere and subsequently temper rolling, and thereafter went through an electrolysis process, has excellent battery performance. The reason has not yet been explained enough why the alkali-manganese cell or the nickel-cadmium battery employing the nickel-plated steel sheet according to this invention, which was nickel-plated and went through the heat treatment, temper rolling, and electrolysis process in the acid solution, has a decreased internal resistance so that the battery performance can be improved. However, when the surface of the nickel plated steel sheet obtained as mentioned above was observed by the use of an atomic force microscope, minute etched-like ruggedness caused by the electrolysis process in the acid solution was seen. Therefore, it may be safely considered that the positive electrode mixture penetrates into the fine concave portions o increase the adhesion with the positive electrode case and increase the contacting areas so that the contact resistance is decreased. Besides, the electrolysis process in the acid solution could have hardly effect on the improvement of battery performance if the nickel-plated steel sheet were only immersed in the acid solution or only subjected to the cathodic treatment in the electrolysis process. But additional treatments of either anodic treatment, or anodic treatment after cathodic treatment, or cathodic treatment after anodic treatment are essential to improve the battery performance. The reason is that the minute ruggedness is not enough formed by the etching through the immersion process in the acid solution or through the cathodic treatment in the acid solution alone but through the anodic treatment either. This was turned out by the observation through the atomic force microscope. The plated steel sheet for battery container of this invention is described more in detail below according to the manufacturing steps thereof. [Steel sheet] First, as a base sheet for the plated metal sheet of this invention, a cold-rolled steel sheet or a cold-rolled steel strip prepared from a low carbon aluminum killed steel commonly used and a non-ageing hyper low carbon steel having niobium or titanium or the like added thereto is used. Usually, the cold-rolled steel strip that has been subjected to cold rolling, electrolytic cleaning, annealing, and temper rolling is used as the base sheet. However, when the plated steel sheet has a nickel-iron alloy layer formed by another heat treatment, that is, re-annealing after nickel-plating, the plated steel sheet needs to undergo another temper rolling. Or it is also possible to use as the base sheet a cold-rolled steel strip having been subjected to cold rolling and thereafter electrolytic cleaning. In his case, through one time annealing process after the nickel-plating the recrystallization annealing of the steel base sheet and the thermal diffusion treatment of the nickel-plated layer simultaneously take place, and subsequently the plated steel sheet undergoes temper rolling. [Nickel-plating] The cold-rolled steel strip prepared through the above mentioned steps, that is, the steps of: cold rolling; electrolytic cleaning; annealing; and temper rolling, undergoes degreasing, rinsing arid pickling in known manner, and thereafter plated with a nickel layer. Or, the cold-rolled steel strip having been cold rolled and electrolytically cleaned is directly plated with nickel. As a nickel plating bath, either of known Watts bath, sulfamine bath, and chloride bath can be applied. Nickel plating includes no-bright plating, semi-gloss plating, and bright plating. However, for the nickel-plating bath mentioned above, the semi-gloss plating bath and the bright plating bath containing brightening agent can also be applied. Both sides or one side of the above-mentioned cold-rolled steel strip are plated with nickel in the above-mentioned nickel plating bath. It is desirable to apply a nickel-plating layer with a thickness of 0.5-5 M m to the side of the steel strip to be the inside surface of the battery container and more desirably 1.0-2.5 µ m thick. With a nickel-plating layer of less than 0.5 µ- m thick, the plated steel sheet has deteriorated corrosion resistance against the strong-alkali solution filling the battery container and the more steel desolves from the steel base sheet, thus unfavorably reducing the battery performance. On the other hand, with a nickel-plating layer exceeding 5 µm thick, the plated steel sheet no longer contributes to the improvement of the battery performance but also unsuitable for Continuous production thereof and further economically unfavorable. On the other hand, the side of the steel strip to be the outside surface of the battery container may be enough plated with a nickel layer of at most 5 µ m thick, or in some extreme cases, even nickel-plating itself is dispensable. This is because the features of the outside surface of a battery container does not affect its battery performance in any way, and in addition, the outside surface may be provided with an organic resin layer by coating or the like, so the outside of the battery container is required to have not so much corrosion resistance as required for the inside surface of the container. However, a nickel-plating layer of about 0.2-2.5 Ui m thick my be preferably formed from the viewpoint of rust prevention and adhesion to the organic resin coating that is spread over the outside surface. The upper limit of the thickness of nickel plating layer is 5 U m considering its efficient continuous-productivity and cost. LHeat Treatment] In the manufacturing process of the plated steel sheet for battery containers of this invention, the heat treatment after nickel plating is not always necessary. However, it is desirable from the viewpoint of corrosion resistance and workability of the outside surface of the battery container to apply the heat treatment. Through the heat treatment, a double layer consisting of a lower nickel-iron alloy layer and an upper softened nickel layer can be formed between the nickel layer and the base steel sheet, or the entire nickel plating layer can be made into a nickel-iron alloy layer, thus changing the hard and fragile nickel layer into a double layer consisting of a lower nickel-iron alloy layer and an upper nickel layer or into a single layer of nickel-iron alloy having toughness. Namely, through the heat treatment or the annealing after rolling, the steel is recrystallized and softened, and at the same time its fibrous structure having plating istortion is crystallized so as to improve the corrosion resistance of its processed portion. For this purpose, the plated steel sheet needs to be heat treated at 450°C or more, for example, desirably through a heat treatment at 450-650 °C for 4-15 hours by box annealing method or a heat .treatment at 600-850°C for about 0.5-3 minutes by continuous annealing method. [Temper Rolling] When the plated steel sheet is heat treated after the nickel plating as mentioned above, it is indispensable to apply temper rolling thereto. For, there occurs yield elongation at the base steel sheet subjected to the heat treatment, which causes cracks and stretcher strains of some mil meters wide at the bottom portion of a battery container when the plated steel sheet is deep drawn into the battery container body. Temper rolling is means for inhibiting these defects. Usually light reduction rolling with elongation rate of 1-2% is conducted using a work roll bright-finished by whetstone grinding or a work roll dully finished by shot blasting. Thus, the above-mentioned yield elongation can be dissolved at the same time to make a finish of the surface of the plated steel sheet. [Acid Solution] The electrolytic treatment in an acid solution, which is the characteristic process of the manufacturing method of the plated steel sheet for battery containers of this invention, is applied to a nickel plated steel sheet or to a steel sheet which has been nickel plated, heat treated, and temper rolled sequentially in order. As the acid solution, in addition to sulphuric acid solution, hydrochloric acid solution and a mixed solution containing these acids, inorganic acid solution such as phosphoric or nitric acid solution, and organic acid solution such as acetic acid solution may be used. However, totally considered from the views of ching-liability of the nickel plating surface, disposal of the waste fluid, and cost, it is desirable to use sulphuric acid solution, hydrochloric acid solution or mixed solution containing these acids. The density of the acid solution is desirably 1-10 percent by weight, and the temperature thereof is desirably between ordinary temperature and around 50 °C . When the acid density of the solution is less than 1%, the nickel plating surface is remarkably less etched by the electrolytic treatment even if the temperature of the acid solution is raised. This is undesirable because it takes a long time to obtain a desired nickel plating surface provided with minute ruggedness. This is disadvantageous for continuous production thereof. On the other hand, when the acid density exceeds 10 percent by weight, the nickel plating surface is etched too much to be provided with minute ruggedness even with the temperature of the acid solution kept low. It is also undesirable from the point of economy because the more amount of the acid solution will be taken out together with the nickel plated steel strip running during the continuous production. Further in this case, keeping the temperature of the acid solution below ordinary temperature needs some cooling means, which is also economically undesirable. In addition, with the acid solution having a temperature lower than ordinary temperature, etching-liability of the nickel plating surface is unfavorably decreased. On the other hand, when the temperature of the acid solution is raised to 50 °C or more, the nickel plating surface is etched too much to be provided with minute ruggedness. In addition, it is undesirable because the higher temperature of the acid solution could corrode manufacturing apparatus. From these viewpoints, it is desirable to conduct the electrolytic treatment with the acid solution having a density of 3-7 percent by weight and the temperature of the acid solution kept at between ordinary temperature and 40 °C . [Electrolytic Treatment] Next, as the method of the electrolytic treatment, either conductor roll energizing method or grid-grid method may be applied, and the nickel plated steel sheet is required to be anodized, cathodized and again anodized in acid solution, or anodized and thereafter further cathodized. In any case, it is essential that the nickel plated steel sheet serves as the anode. The quantity of electricity for anodizing is desirably 10-200 coulombs/dm 2 and more desirably 30-100 coulombs/dm 2 . When the quantity of the electricity for anodizing is less than 10 coulombs/dm 2 , the surface of the nickel plated steel sheet cannot be provided with desired minute ruggedness. On the other hand, when the quantity of the electricity for anodizing exceeds 200 coulombs/dm 2 , it is undesirable because the nickel plating surface is etched too much and the corrosion resistance might be deteriorated. In the above-mentioned electrolytic treatment, the quantity of electricity for the cathodic process may be not limited. This is because the nickel plating surface is hardly etched through a cathodic process. The conductor roll may be preferably a roll made of hastelloy, considering the corrosion by acid solution, and the electrode as cathode or anode may be preferably formed of lead, binary alloy consisting of lead-tin, ternary alloy consisting of lead-tin-silver, and titanium plated with platinum from the similar viewpoint. After subjected to the electrolytic treatment as mentioned above, the plated steel sheet is rinsed and dried to be made a plated steel, sheet: for battery containers of this invention. Another preferable method is that in order to efficiently and uniformly etch the nickel plating surface, an electrolytic treatment may be conducted in alkaline solution such as containing caustic soda and sodium carbonate prior to the above-mentioned electrolytic treatment so as to mprove the wettability of the nickel plated steel sheet by acid solution. [Embodiment] This invention is explained more concretely below by showing examples and comparative examples . Cold rolled and annealed low carbon aluminum killed steel sheets each having a thickness of 0.25 mm and 0.40 mm were used as base steel sheets to be plated with nickel. The chemical compositions of these base steel sheet are as follows. C: 0.04% (% means percentage by weight, the same for the followings) , Mn: 0.18%, Si: 0.01%, P: 0.013%, S: 0.008%, Al: 0.056%, N: 0.0032%. The above mentioned steel sheets were subjected to alkali electrolytic degreasing (current density for cathodizing and anodizing processes were each 5A/dm 2 and electrolysis duration were each 10 seconds.) in a manner that they went through anodic electrolysis and subsequently through cathodic electrolysis in the alkaline solution having a bath temperature at 80 °C and having a density of 35 g/1 caustic soda. The thus treated steel sheets were rinsed and subsequently pickled under the condition of: density of 50g/l sulfuric acid; bath temperature at 30°C; and dipping duration of 10 seconds, and again rinsed to be plated with nickel under the following conditions . (l)The conditions of nickel plating Bath composition: Nickel sulfate 350 g/1 Nickel chloride 40 g/1 Boric acid 40 g/1 Lauryl acid soda 0.5 g/1 pH : 4 . 1 ~ 4 . 6 Bath temperature: 55 ± 2 °C Current density: lOA/dm 2 mode: nickel pellets (A titanium basket filled with nickel pellets was enveloped by a polypropylene bag) Both sides of the steel sheet were plated with a mat-finished nickel layer under the above-mentioned conditions. The thickness of the nickel plating layer was adjusted by varying the duration of electrolysis. A part of each sample of the obtained nickel plated steel sheets was heat treated in a non-oxidation atmosphere with 6.5% of hydrogen, the remainder being nitrogen, and dew point of -55 °C for varied soaking period of time at varied soaking temperatures. Subsequently, the sample was temper rolled with the elongation rate of 1.0% using a bright finish work roll, and then electrolytically treated in acid solution. The other part of each sample of the obtained nickel plated steel sheets was not heat treated nor temper rolled but electrolytically treated in acid solution. Thickness of the nickel plating layers on both sides of the steel sheet, whether heat treatment was conducted or not, soaking temperature and soaking period of time for heat treatment, whether acid solution was used or not, and the conditions of acid solution for each process are all shown in Table 1. [Manufacturing of Battery Container] The nickel plated steel sheet obtained in the manners described above was formed into a battery container using the following forming methods. (1) Deep drawing method The nickel plated steel sheet of 0.25 mm thickness was blanked out and formed into a cylindrical container body for battery of 49.5 mm in height and 13.8 mm in outside diameter by deep drawing comprised of 10 steps. .2) DI forming method The nickel plated steel sheet of 0.4 mm thickness was punched out into a blank of 41 nun in diameter to be formed into a cup of 20.5 mm in diameter. Subsequently, it: was formed into a cylindrical container body for battery of 13.8 mm in outside diameter, 0.2 mm in wall thickness and 56 mm in height by redrawing and 3-step-ironing using DI forming machine. Further the upper part of the container body was trimmed to obtain a LR6 type battery container of 49. 3 mm in height. (3,1 DS forming method The nickel plated steel sheet of 0.25 mm thickness was punched out into a blank of 58 mm in diameter to be formed into a container body for LR6 type battery of 13.8 mm in outside diameter and 49.3 mm in height by 4-step-drawing and stretching. In the case of applying graphite to the inside surface of the obtained battery container, 20 weight part of graphite powder (average size diameter: 3-10 µ m) and 20 weight part of thermosetting epoxy resin were diluted with methyl ketone and spread over the inside surface of the battery container using air spray. After that, it was dried by heating at 150°C for 10 minutes. The condition of the air spray was selected such that the amount of the graphite coating was to be 8 mg/case after dried. The forming methods for forming each example of the nickel plated steal sheets into a battery container and whether graphite was applied to the inside surface of the battery container or not are also shown in Table 1. Table 1 (Table Removed) [Manufacturing of Battery] An alkaline manganese cell was produced by the following method using each of the battery containers obtained by the methods (l) , (2) , arid (3) explained above. First, manganese dioxide and graphite at the weight ratio of 10:1 were mixed with potassium hydroxide (8 moles) to prepare a positive electrode mixture. Then, the positive electrode mixture was pressed in a mold to prepare a positive electrode pellet in a doughnut-shape having a fixed size, and it was inserted in and pressed to the inside of the obtained battery container. Next, a neck-in forming was made at a fixed position under the edge of the open end of the battery container so as to fix a negative electrode plate, to which a negative electrode electricity collecting rod is spot-welded, to the battery container. Subsequently, a separator made of vinylon unwoven cloth was inserted therein along the inner periphery of the pellet pressed to the battery container. Then, a negative electrode gel consisting of potassium hydrate that was prepared by saturating zinc grain and zinc oxide was inserted in the battery container. After that, a gasket was fixed to the negative electrode plate as an insulator, which was inserted in the battery container and calked to produce an alkali-manganese cell. [Evaluation of Battery Performance] The performance of the thus obtained alkali-manganese cells were evaluated after they were left for four weeks under the condition of temperature at 60 °C and humidity of 95 % RH. The battery performance was determined based on two items: internal resistance (m Q) by alternating current impedance (frequency : 1 kHz) ; and short-circuit current (A) at 1m Q load. Both the internal resistance and the short-circuit current were measured under the condition of temperature Table 1 shows the evaluation results of the battery performance of the obtained batteries together with the manufacturing conditions of the nickel plated steel sheet for battery container. In Table 1, polarity of the electrolytic process in acid solution is represented as shown below. A: Electrolytic treatment using the nickel plated steel sheet as anode; C→A: Electrolytic treatment using the nickel plated steel sheet as cathode, and subsequently as anode; A → C: Electrolytic treatment using the nickel plated steel sheet as anode, and subsequently as cathode. CD represents the current density during electrolytic treatment, and time means the duration of each treatment. The following is the findings obtained from the results shown in Table 1. (1) The examples have each smaller internal resistance and larger short-circuit current than the comparative examples, which clearly shows that they have excellent battery performance. (2) The comparative examples, one of which was immersed in acid solution (comparative example 4) , another of which was subjected to cathodic treatment in acid solution (comparative example 7) , and the other of which were subjected to anodic treatment in acid solution under the condition other than the specified condition (comparative examples 2 and 3) , as well as comparative example 1 which was not subjected to the electrolytic treatment in acid solution, have larger internal resistance and smaller short-circuit current than each of the examples, which shows that these comparative examples have inferior attery performance. (3) The battery performance of example 5 and example 10 each having graphite coated inside surface is superior to those of the other examples and comparative examples, which shows that application of graphite coating to the inside surface of the battery container provides remarkably improved battery performance. Table 2 (Table Removed) [Effect of the Invention ] The plated steel sheet for battery container of this invention is suitable for a continuously productive material for a battery container which contributes to more excellent performance of the battery in comparison with those produced from the prior art surface treated steel sheet for battery containers, by simple means. Thus, the plated steel sheet of this invention is extremely valuable in the industrial field. In addition, when the plated steel sheet for battery container is formed into a cylindrical body having a bottom portion and the thus formed cylindrical container has the inside surface thereof spread with graphite, improved performance of the battery can be provided. Further according to this invention, when the above-mentioned battery container is packed with a negative electrode rod, a positive electrode mixture, a negative electrode gel, and others, a most excellent battery or cell can be provided. The alkali-manganese cell or the nickel-cadmium battery employing the battery container obtained by forming the plated steel sheet for battery container of this invention have small internal resistance and large short-circuit current, thus exhibiting enhanced battery performance. WE CLAIM: - 1. A manufacturing method of a plated steel sheet for battery containers characterized in that: degreasing or degreasing plus pickling the steel sheet; thereafter plating the steel sheet with nickel; and subsequently applying to the nickel plated steel sheet either an anodic treatment, or an anodic treatment after cathodic treatment, or a cathodic treatment after anodic treatment, in the acid solution of 1-10 percent density by weight. 2, A manufacturing method as claimed in claim 1, wherein: the nickel plated steel sheet is heat treated in a non-oxidation atmosphere; temper rolling is applied to the heat treated nickel-plated steel sheet. 3, The manufacturing method as claimed in claims 1 or 2, wherein the above-mentioned electrolysis treatments in the acid solution are conducted in sulphuric acid solution or in hydrochloric acid solution. 4. A manufacturing method of a plated steel sheet for battery containers substantially as hereinbefore described with reference to the foregoing examples.

Documents:

2929-DEL-1997-Abstract.pdf

2929-DEL-1997-Claims.pdf

2929-del-1997-complete specification (granted).pdf

2929-del-1997-correspondence-others.pdf

2929-del-1997-correspondence-po.pdf

2929-DEL-1997-Description (Complete).pdf

2929-DEL-1997-Form-1.pdf

2929-del-1997-form-13.pdf

2929-del-1997-form-19.pdf

2929-DEL-1997-Form-2.pdf

2929-DEL-1997-Form-3.pdf

2929-DEL-1997-Form-4.pdf

2929-del-1997-pa.pdf

2929-del-1997-petition-137.pdf

2929-del-1997-petition-138.pdf