JP2004127567A - Current collector component for battery, and battery using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a current collector component for batteries, having proper current collection properties and a battery, especially the current collector component for batteries having high capacity and improved current collection properties and the battery. <P>SOLUTION: The current collection component for batteries comprises a plating nonwoven cloth that forms pores only on the surface, includes a surface porous plating fiber, having a plated surface on the surface, and is made of a plating fiber having a plated layer on the surface. The total surface area of fiber per unit volume in the plated non-woven cloth is preferably 500 cm<SP>2</SP>/cm<SP>3</SP>or larger. In the battery, the current collector component for batteries is used. <P>COPYRIGHT: (C)2004,JPO

Description

【００９４】
この表１の電池理論容量の結果から明らかなように、本発明の表面多孔メッキ繊維を含む集電材は高容量化が可能で、しかも集電性能に優れるものであった。また、４．０Ｃ利用率の結果から明らかなように、本発明の集電材はハイレート放電での集電性能に優れるものであった。
【００９５】
【発明の効果】
本発明の集電材は集電性に優れている。また、高容量の電池を製造できるものである。
【００９６】
本発明の電池は集電性能に優れ、高容量の電池であることができる。
【図面の簡単な説明】
【図１】（ａ）　本発明の表面多孔メッキ繊維の断面映像模式図
（ｂ）　本発明の別の表面多孔メッキ繊維の断面映像模式図
（ｃ）　本発明の表面多孔メッキ繊維の繊維軸方向における断面映像模式図
（ｄ）　本発明の別の表面多孔メッキ繊維の繊維軸方向における断面映像模式図
【図２】本発明のアルカリ二次電池の一部を切り欠いた斜視図
【図３】集電体が渦巻き円状に巻回された図２のＡ−Ａ線断面図
【図４】集電体が渦巻き角状に巻回された図３に対応する断面図
【図５】集電体が蛇腹状に屈曲積層された図３に対応する断面図
【符号の説明】
１０　表面多孔メッキ繊維
１１　細孔
１２　繊維表面
１３　開孔部
１０１　電池
１０２　正極
１０２ａ　ニッケル片
１０３　負極
１０４　セパレータ
１０４ａ　第１セパレータ
１０４ｂ　第２セパレータ
１０６　発電体
１０７　電池ケース
１０７ａ　缶底
１０７ｂ　くびれ部
１０８　封入板
１０８ａ　突起
１０９ａ　ロア絶縁体
１０９ｂ　アッパ絶縁体[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a current collector for a battery and a battery using the same.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, batteries, particularly alkaline secondary batteries, are highly reliable and can be reduced in size and weight, and thus are often used as power sources for various devices from portable devices to large-scale industrial equipment. In this alkaline secondary battery, in most cases, a nickel hydroxide electrode is used as a positive electrode. The nickel hydroxide electrode has a structure in which a positive electrode active material for causing a battery reaction is supported on a current collecting material sharing a current collecting function. As a current collecting material in that case, a sintered nickel plate obtained by sintering nickel powder, a punched nickel plate, and the like have been widely used. The capacity of the battery is determined by the amount of the active material to be filled in the gaps of the nickel plate, and the amount of the active material is determined by the porosity of the nickel plate, so that the porosity of the nickel plate is made as large as possible. It is desirable.
[0003]
However, the sintered nickel plate has a punched nickel plate as a base material, and the base material has a low porosity of 75 to 80% and a low nickel content in a nitrate solution. It was necessary to repeat the filling cycle of impregnation and neutralization several times or more, and as the filling cycle was repeated, the penetration of the nitrate solution into the inside of the nickel plate became worse, so it was difficult to fill the active material with high density. . Therefore, recently, with the demand for smaller and higher capacity batteries, a three-dimensional network structure that has a large porosity and can increase the packing density of the active material in order to increase the packing density of the active material of the current collector. A current collector made of a body is employed.
[0004]
As a current collector having a three-dimensional network structure, for example, a “nickel-plated nonwoven fabric electrode made of fibers and subjected to a hydroentanglement process on a web and then subjected to electroless nickel plating” has been proposed (Japanese Patent Laid-Open No. 5-290838). ).
[0005]
[Patent Document 1]
JP-A-5-29038
[0006]
[Problems to be solved by the invention]
However, the nickel-plated nonwoven fabric electrode disclosed in the above publication has a poor current collecting property, so that the utilization rate of the active material is low and high-rate discharge cannot be performed. In particular, when the thickness is increased to increase the capacity, the current collecting property is poor.
[0007]
The present invention has been made in order to solve the above-described problems, and has an object to provide a battery current collector and a battery having excellent current collecting properties, and in particular, to provide a battery current collector and a battery having a high capacity and excellent current collecting properties. And
[0008]
[Means for Solving the Problems]
The invention according to claim 1 is directed to a plated non-woven fabric comprising only plated fibers having a plated layer on the surface, including surface porous plated fibers having pores formed only on the surface and having a plated layer on the surface. A current collector for a battery, comprising: Porous surface-coated fibers having pores formed only on the surface and having a plating layer on the surface have not only a large surface area but also excellent adhesion to the active material. A current collector for a battery containing fibers (hereinafter sometimes simply referred to as “current collector”) is excellent in current collection. In addition, since the surface porous plated fiber has excellent current collecting properties, the amount of fibers constituting the current collecting material can be reduced, and the porosity of the current collecting material can be increased. Since the amount can be increased, a high-capacity battery can be manufactured. In addition, the conventional fiber having voids on the surface as disclosed in Japanese Patent Application Laid-Open No. 5-290838 is not a fiber having pores formed only on the surface, but also having pores formed inside. Although the surface area is large, sufficient current collecting performance cannot be obtained due to low adhesion of the active material to the fibers.
[0009]
The invention according to claim 2 is characterized in that the shape of the opening of the pore is substantially circular or substantially polygonal, and the average diameter of the opening is 0.5 to 15 μm. Item 1. A current collector for a battery according to item 1. " When the pores have such a shape and size, the adhesion between the active material and the surface porous plating fibers is particularly excellent, and as a result, the current collection is excellent, and a high-capacity battery is more easily manufactured. .
[0010]
The invention according to claim 3 is “the current collector for a battery according to claim 1 or 2, wherein the average depth of the pores is 0.1 to 15 μm”. When the pores have such a depth, the adhesiveness between the active material and the surface porous plating fibers is particularly excellent, and as a result, the current collection is excellent and a high-capacity battery is more easily manufactured.
[0011]
The invention according to claim 4 is that the number of the pores is 10,000 μm on the fiber surface. ² The current collector for a battery according to any one of claims 1 to 3, characterized in that the number is 10 to 55000 pieces per battery. The presence of such a large number of pores increases the number of points of adhesion between the active material and the surface porous plating fibers, so that the current collection is excellent and a high-capacity battery is more easily manufactured.
[0012]
The invention according to claim 5 is characterized in that a total fiber surface area per unit volume of the plated nonwoven fabric is 500 cm. ² / Cm ³ The current collector for a battery according to any one of claims 1 to 4, characterized by the above. As described above, since the total surface area of the fibers is large, the number of contact points between the active material and the surface porous plating fibers is increased, so that the current collecting property is excellent and a high-capacity battery is more easily manufactured.
[0013]
The invention according to claim 6 is "a battery using the battery current collector according to any one of claims 1 to 5". As described above, since the battery uses the current collecting material, the battery has excellent current collecting performance and can have a high capacity.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
The current collector of the present invention has pores formed only on the surface, and includes surface porous plating fibers having a plating layer on the surface, and not only has a large surface area, but also has excellent adhesion to the active material. Therefore, it has excellent current collecting properties. In addition, since the surface porous plated fibers have excellent current collecting properties, the amount of fibers constituting the current collecting material can be reduced, the porosity of the current collecting material can be increased, and as a result, the active material filling amount can be increased. Therefore, a high-capacity battery can be manufactured.
[0015]
Such a current collector of the present invention can be manufactured, for example, as follows.
[0016]
First, a non-porous fiber is prepared. The non-porous fiber is a fiber having at least a surface mainly composed of a thermoplastic resin and having no pores on the fiber surface, and is heated (for example, heated at a temperature of 50 ° C. or more, preferably at a temperature of 80 ° C. or more) to the fiber surface. Any fiber may be used as long as the fiber includes a thermoplastic resin that is melted by the method (1).
[0017]
Such non-porous fibers can be obtained, for example, by a synthetic fiber obtained by a melt spinning method, which is a conventional fiber manufacturing method, by a spun bond method, a melt blow method, or a flash spinning method, which is a conventional nonwoven fabric manufacturing method. Fiber or a fiber whose core part is made of a natural fiber or inorganic fiber and whose sheath part is made of a thermoplastic resin can be used.
[0018]
Examples of the synthetic fiber include a synthetic fiber made of a thermoplastic resin (for example, a polyolefin fiber, a polyester fiber, or a polyamide fiber), and the synthetic fiber is made of one type of thermoplastic resin. Or a composite fiber in which two or more different thermoplastic resins are conjugated or mixed. Examples of the latter conjugate fiber include conjugate fibers in which two or more kinds of thermoplastic resins having different melting points are conjugated. For example, copolymer polyester / polyester, copolymer polypropylene / polypropylene, polypropylene / polyamide, polyethylene / polypropylene , A composite fiber made of a combination of resins such as polypropylene / polyester or polyethylene / polyester. In the case of a core-sheath type composite fiber having a high melting point resin in the core and a low melting point resin in the sheath, the surface porous fiber (with a plating layer of the surface porous plating fiber provided without causing fiber shrinkage or thread breakage). Fibers, which are not described below).
[0019]
Further, the non-porous fiber is preferably composed entirely of fiber-forming thermoplastic resin, but such a fiber that the core portion has a decomposition temperature without a melting point, for example, rayon fiber, acetate fiber, A fiber made of a fiber such as a wool fiber or a carbon fiber, and a sheath part made of a thermoplastic resin can also be used. As the non-porous fiber, a fiber whose core portion is made of, for example, an inorganic fiber such as glass fiber, ceramic fiber, or metal fiber, and whose sheath portion is made of a thermoplastic resin can also be used. The sheath component of these fibers can be obtained, for example, by coating with a coating or the like.
[0020]
In the non-porous fiber “at least the surface of which is mainly composed of a thermoplastic resin”, the area occupied by the thermoplastic resin on the fiber surface is 50% or more of the fiber surface area (preferably 60% or more, more preferably 70% or more, particularly Preferably 90% or more, and most preferably 100%).
[0021]
The cross-sectional shape of the non-porous fiber does not need to be circular, and may be non-circular (for example, polygon such as triangle, ellipse, ellipse, T-shaped alphabet, etc.). Further, it may be divided into fibrils by an external force.
[0022]
The average diameter and length of the non-porous fibers are not particularly limited, but the average diameter of the fibers is preferably 1 μm or more, more preferably 30 μm to 55 μm. Here, the “average diameter” of the fiber is, when the cross-sectional shape of the fiber is other than a circle, the diameter of a circle having the same area as the cross-sectional area of the fiber, and the number average by sampling from any 500 or more points of the fiber. Fiber diameter. In the case of commercially available fibers, when the number average fiber diameter is specified in the catalog or specification, the value may be used as the average diameter of the fiber, and the fineness is specified in the catalog or specification. In this case, a value converted from the fineness may be used as the average diameter.
[0023]
Next, solid particles are fixed to the surface of the non-porous fiber as described above to form solid particle fixed fibers.
[0024]
The solid particles have a melting point or a decomposition temperature higher than the melting point of the thermoplastic resin constituting the surface of the non-porous fiber, and are either inorganic or organic as long as the solid particles can be removed after fixing. There can be. As such solid particles, for example, solid particles that dissolve in a solvent (eg, water, an aqueous solution, an acid, an alkaline aqueous solution, etc.) that does not substantially dissolve the thermoplastic resin constituting the surface of the non-porous fiber ( For example, there are water-soluble inorganic substances, metal salts, water-soluble resins, and metals. Such solid particles can be extracted and removed using the solvent. In addition to the extraction and removal, solid particles that can be removed by vibration, ultrasonic cleaning, fiber shrinkage, or processing for improving the releasability of the fiber surface may be used. More specifically, examples thereof include sodium chloride, calcium chloride, calcium carbonate, other various metal salts, water-soluble resin, metal particles, ceramics, zeolite, and other various inorganic substances.
[0025]
The melting point or decomposition temperature of the solid particles is such that the surface of the non-porous fiber is melted or deformed by the heat of the heated solid particles, and the solid particles are fixed to the fiber surface so that the non-porous fiber surface is formed. It is necessary that the melting point of the thermoplastic resin is higher than the melting point of the resin having the lowest melting point.
[0026]
The average particle diameter of the solid particles is not particularly limited, but the average particle diameter of the solid particles is preferably 0.1 to 20 μm so that pores having excellent adhesion with the active material can be formed, More preferably, it is 5 to 15 μm. The average particle diameter of the solid particles refers to the number average particle diameter of the solid particles. The “number average particle size” is obtained by taking an image of a solid particle by enlarging it with a scanning electron microscope or the like, measuring the particle size of any 500 or more solid particles, and dividing the measured value by the measured number. Value. At this time, when the solid particles are not spherical, the diameter of the circumcircle of each solid particle that can be confirmed in the captured image of the solid particle is defined as the particle size of each particle. In the case of commercially available solid particles, if the number average particle diameter is specified in a catalog or specification, that value may be used as the average particle diameter of the solid particles.
[0027]
The solid particles are fixed to the surface of the non-porous fiber to form the solid particle-fixed fiber. As a method of fixing the solid particles, for example, the solid particles as described above are formed on the surface of the non-porous fiber. The solid particles heated at a temperature within the range of maintaining the shape as a solid, up to the melting point of the thermoplastic resin or higher and lower than the melting point or the decomposition temperature of the solid particles, are brought into contact with the non-porous fibers, and the surface of the non-porous fibers is There is a method of fixing by fusion or deformation. Further, a method of fixing the non-porous fiber surface by fusing or deforming the non-porous fiber surface by contacting the solid particles as described above while heating the non-porous fiber surface to a temperature higher than the melting point of the thermoplastic resin. But it's fine. The former method is more preferable because the solid particles are not buried and pores can be reliably formed.
[0028]
The method of contacting the solid particles with the non-porous fibers is not particularly limited as long as the solid particles can be fixed to the non-porous fibers. For example, (1) containing the heated solid particles A method of blowing an airflow onto non-porous fibers; (2) a method of allowing heated solid particles to fall naturally onto non-porous fibers; and (3) shaking a vessel containing heated solid particles and non-porous fibers. (4) dipping the non-porous fibers in the heated solid particles, or (5) exposing the non-porous fibers in the fluidized bed of the heated solid particles.
[0029]
By removing the solid particles of the solid particle-fixed fibers thus formed, surface porous fibers can be obtained.
[0030]
The method for removing the solid particles of the solid particle-fixed fibers is not particularly limited as long as the solid particles of the solid particle-fixed fibers can be removed, and for example, substantially removes the thermoplastic resin constituting the non-porous fiber surface. There is a method in which solid particles that are dissolved in a solvent that does not dissolve are removed using the solvent. For example, a water-soluble inorganic substance, a metal salt, a water-soluble resin, a metal, or the like can be used as the solid particles, and the solid particles can be removed using, for example, water, an aqueous solution, an acid, or an alkaline aqueous solution as a solvent. In particular, a method of using a metal salt or a water-soluble resin as the solid particles and removing the solid particles with water is preferable because the production cost is less burdened. Examples of such a metal salt include sodium chloride, calcium chloride, ammonium chloride, sodium hydrogen carbonate, potassium hydrogen carbonate, and the like. Examples of such a water-soluble resin include polyvinyl alcohol, polyethylene glycol, and polyacrylic acid.
[0031]
Other methods for removing the solid particles of the solid particle fixed fibers include, for example, a method of vibrating the solid particle fixed fibers to separate the solid particles, a method of ultrasonically cleaning the solid particle fixed fibers to separate the solid particles, or a method of removing the solid particles. A method of extending or shrinking the fibers of the particle-fixing fibers to exfoliate the solid particles can be used.
[0032]
When surface porous fibers are produced by such a production method, pores can be formed only on the fiber surface while maintaining various properties such as fiber strength inherent of the non-porous fibers. In addition, since pores can be formed in accordance with the shape and size of the solid particles, the use of solid particles having a shape and size corresponding to the shape and size of the active material used for the electrode improves adhesion to the active material. Excellent surface porous fibers can be produced.
[0033]
Next, a nonwoven fabric is formed using the surface porous fibers thus obtained. The nonwoven fabric may be formed using not only the surface porous fiber but also a fiber having pores other than the surface or a non-porous fiber having no pore at all other than the surface porous fiber.
[0034]
As a method for producing this nonwoven fabric, first, a fiber web is formed by a dry method such as a card method or an air lay method, or a wet method. In particular, since the fiber web obtained by the wet method has a small variation in the basis weight and thickness, a uniform current collector can be obtained. As a result, an electrode having a uniform thickness can be formed by using the current collector, and an electrode group having excellent adhesion can be formed by winding the electrode, so that a battery having excellent charge / discharge characteristics can be obtained. Can be.
[0035]
Next, the fibrous web may be used as it is as a nonwoven fabric, but it is preferable to perform a entanglement treatment or a heat treatment to increase the strength characteristics to form a nonwoven fabric. As the confounding process, for example, a hydroentanglement process or a confounding process using a needle punch can be adopted. When the confounding treatment is performed, the fibers are entangled with each other, the number of contact points between the fibers is increased, the strength characteristics are improved, and the porosity can be adjusted to an appropriate value.
[0036]
The heat treatment can enhance the overall strength characteristics by fusing the contact points of the fiber web constituent fibers with each other. It is necessary to appropriately adjust the temperature of the heat treatment so as not to block the pores of the surface porous fiber. This heat treatment temperature can be appropriately determined experimentally.
[0037]
Either of the entanglement treatment and the heat treatment may be performed, but it is preferable to perform the heat treatment after the entanglement treatment because the strength characteristics of the obtained nonwoven fabric can be significantly improved.
[0038]
Next, the nonwoven fabric may be subjected to a plating treatment to form a plated nonwoven fabric containing surface porous plating fibers, that is, a current collector. It is preferable to improve the conductivity and the adhesion to the metal plating formed on the fiber surface by improving the permeability and firmly binding the metal ions.
[0039]
Examples of such a hydrophilic treatment include a sulfonation treatment, a fluorine gas treatment, a graft polymerization of a vinyl monomer, a surfactant treatment, and a treatment for imparting a hydrophilic resin. In particular, a sulfonation treatment, a fluorine gas treatment, or a graft treatment with a vinyl monomer is preferable because the plating film hardly falls off for a long period of time and the surface resistance hardly increases.
[0040]
More specifically, the sulfonation treatment can be performed by immersing the nonwoven fabric in a solution such as fuming sulfuric acid, sulfuric acid, sulfur trioxide, chlorosulfuric acid, or sulfuryl chloride. Among these, sulfonation treatment with fuming sulfuric acid is preferred because it has high reactivity and can be relatively easily sulfonated.
[0041]
In the fluorine gas treatment, for example, a mixture of a fluorine gas diluted with an inert gas (eg, a nitrogen gas, an argon gas, or the like) and at least one gas selected from an oxygen gas, a carbon dioxide gas, a sulfur dioxide gas, and the like is used. It can be carried out by contacting the gas with the nonwoven fabric. In addition, the method of preliminarily adhering the sulfur dioxide gas to the nonwoven fabric and then bringing it into contact with the fluorine gas is an efficient and permanent hydrophilization treatment method.
[0042]
The graft treatment of the vinyl monomer impregnates the nonwoven fabric with at least one kind of graft polymerization liquid selected from acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, vinylpyridine, or styrene, and irradiates ultraviolet rays. Processing can be mentioned. Among these, acrylic acid is preferred because it does not cause the plating film to fall off or increase in surface resistance for a long time.
Next, a plating process is performed on the nonwoven fabric or the nonwoven fabric subjected to the hydrophilization treatment to form a plated layer on the surface of the surface porous fiber to form the surface porous plated fiber, and at the same time to manufacture a plated nonwoven fabric, that is, a current collector. it can.
[0043]
Although this plating method is not particularly limited, nickel plating is preferably performed by an electroless plating method. If necessary, it is preferable to further form an electrolytic plating film by an electrolytic plating method on the electroless plating film formed by the electroless plating method.
[0044]
More specifically, the “electroless plating method” includes a catalyst application step and an electroless plating step. The catalyst application step includes a method of treating with a stannous chloride aqueous hydrochloric acid solution and then catalyzing with a palladium chloride aqueous hydrochloric acid solution, and a method of immobilizing only a hydrochloric acid solution of barium chloride containing an amino group of a curing agent. However, the former method is preferable because the plating film has excellent uniformity in film thickness.
[0045]
The electroless plating step is generally a method of reducing nickel with a reducing agent in an aqueous solution containing a nickel salt such as nickel nitrate, nickel chloride, and nickel sulfate.If necessary, a complexing agent, a pH adjuster, A buffer, a stabilizer and the like are added. In particular, in order to obtain a nickel film having high purity, it is preferable to use a hydrazine derivative such as hydrazine hydrate, hydrazine sulfate, or hydrazine oxide as a reducing agent.
[0046]
The “electrolytic plating method” is performed using a plating bath. As a plating bath, a Watt bath, a chloride bath, and a sulfamic acid bath can be used. Additives such as a pH buffer and an interfacial buffer may be used in these baths. An electroless plated non-woven fabric is connected to the cathode in this bath, the nickel counter electrode is connected to the anode, and then a direct current or pulsed intermittent current is applied to further form an electrolytic plated layer on the electroless plated layer. be able to.
[0047]
For example, the surface porous plating fiber of the present invention produced in this manner has pores formed only on the surface, and has a plating layer formed on the surface. The surface porous plating fiber of the present invention will be described with reference to FIGS. 1A and 1B, which are schematic cross-sectional images of the surface porous plating fiber. Is formed. Here, “only the surface of the fiber” means that substantially only pores visible from the surface (for example, visible in an image of the surface of the fiber taken with a scanning electron microscope) are formed on the surface of the surface porous plated fiber. Means that it is. As is clear from FIGS. 1 (a) and 1 (b), when the pores are observed from the fiber surface side, the deepest portion of the pores 11 in the thickness direction of the fibers is opened. It can be confirmed from the department. From another perspective, the pores are shaped such that the fiber surface is depressed or a part of the fiber surface is hollowed out. For example, when a particulate material that can be extracted with a certain solvent is mixed into a fiber-forming thermoplastic resin and spun from the fiber, the particulate material is extracted and removed to form a plating layer. However, since the deepest part of the pores in the thickness direction of the fiber cannot be observed from the fiber surface, it does not correspond to the surface porous plated fiber of the invention. Although such a fiber has a large surface area, it has insufficient adhesion to an active material, and it is difficult to obtain sufficient current collecting performance.
[0048]
The shape of the pores of the surface porous plated fiber of the present invention does not deviate from the concept of the pores (as deviating from the concept of the pores, for example, streak, line, band, mountain range, groove, or There is no particular limitation, and a semi-spherical shape is preferable. The term “semi-spherical” includes a shape that is a substantially semi-spherical, substantially semi-elliptical, or semi-polyhedral, and further has irregularities on a surface forming the substantially semi-spherical, substantially semi-elliptical, or semi-polyhedral. Including shape. Further, 10% to 90%, preferably 30% to 70%, of the volume of the solid particles used in the above-described production method is fixed to the surface of the non-porous fiber, and the solid particles are removed from the surface of the non-porous fiber. And the shape of depressions or pores as formed when the
[0049]
The shape of the opening on the fiber surface of the pores of the surface porous plating fiber of the present invention is preferably substantially circular or substantially polygonal. When the pores have such a shape, the pores have excellent adhesion to the active material, and as a result, have excellent current collecting properties, so that a high-capacity battery is more easily manufactured. Here, the opening 13 refers to a contour formed by the opening of the pores 11 formed on the surface 12 of the surface porous plating fiber as shown in FIGS. 1 (a) and 1 (b).
[0050]
The average diameter of the opening is preferably 0.5 to 15 μm, more preferably 1 to 15 μm, and even more preferably 5 to 15 μm. When the average diameter of the opening is 0.5 to 15 μm, the adhesion to the active material is further increased. Here, the "average diameter of the aperture" means that the diameter of the circumcircle of the aperture, which can be confirmed in an image of the fiber by photographing the side of the fiber by enlarging it with a scanning electron microscope or the like, Means the number-average opening diameter obtained by sampling from 500 or more locations.
[0051]
In addition, the major axis of the opening is preferably 5 times or less the minor axis, more preferably 3 times or less, and more preferably 2 times or less so that the active material has excellent adhesion. More preferred. The “major axis of the opening” refers to the longest straight line connecting any two points on the contour of the opening in the pores appearing on the image of the fiber side surface by a scanning electron microscope or the like. Refers to the length, "the minor axis of the aperture" is the length of the longest straight line of any straight line connecting two points where the straight line orthogonal to the major axis of the aperture and the contour of the aperture intersect Point to. When there are three or more points where the outline of the opening intersects with one straight line perpendicular to the major axis of the opening, the straight line connecting any two of these points The longest straight line is a straight line connecting the two points. The comparison value between the major axis and the minor axis of the opening is a number average comparison value obtained by sampling from arbitrary 500 or more pores.
[0052]
The depth of the pores is not particularly limited as long as the pores are formed only on the surface of the fiber, but the average depth of the pores is excellent so that the adhesiveness with the active material is excellent. Is preferably from 0.1 to 15 μm, more preferably from 3 to 10 μm, even more preferably from 5 to 10 μm. Here, the “average depth of pores” refers to the depth of the deepest portion of each pore that can be confirmed by taking an image of the cross-section of the surface porous plating fiber by enlarging it with a laser microscope or the like, and checking the image of the surface porous plating fiber. As for the length, it refers to the number average pore depth obtained by sampling from arbitrary 500 or more pores in the fiber cross section. Here, “the depth of the deepest part of the pore” refers to a line perpendicular to the straight line 12 representing the fiber surface appearing on the image of the fiber cross section, as shown in FIGS. 1 (a) and 1 (b). In this case, the length of the longest straight line among the straight lines connecting the intersection of the perpendicular and the inner wall of the pore and the intersection of the perpendicular and the straight line 12 representing the fiber surface (FIGS. 1 (a) and 1 (b)). Length of b).
[0053]
In the pores that appear on the image of the fiber cross section in the fiber axis direction by a scanning electron microscope or the like, the length of the pores is 0.6 to less than the opening width so that the adhesion to the active material is excellent. It is preferably three times, more preferably 0.7 to 2 times. As shown in FIGS. 1 (c) and 1 (d), the “length of the pores” means both ends points (A and B in FIGS. 1 (c) and 1 (d)) representing the contour of the opening. Refers to half the length of the path from one point to the other point along the line representing the inner wall of the pore, and the `` opening width '' is the width of both ends representing the contour of the opening. It indicates the length of a straight line connecting the points (a in FIGS. 1C and 1D). The comparison value between the opening length and the opening width is a number average comparison value obtained by sampling from arbitrary 500 or more pores.
[0054]
The number of the pores is 10,000 μm on the fiber surface. ² The number is preferably 10 to 55,000, more preferably 10 to 1,000, and even more preferably 50 to 1,000. The number of the pores is 10,000 μm on the fiber surface. ² When the number is 10 or more per unit, the number of contact portions with the active material can be increased, so that a current collector is excellent and a high-capacity battery is more easily manufactured. In addition, the surface of the fiber is 10,000 μm ² When the number of pores is 55,000 or less, the shape and size of the pores can be uniform, and the adhesion to the active material is excellent.
[0055]
The plated nonwoven fabric of the present invention contains the above-mentioned surface porous plated fibers, but the amount is not particularly limited. However, the total fiber surface area per unit volume of the plated nonwoven fabric is 500 cm. ² / Cm ³ As described above, it is preferable to include surface porous plating fibers. When the total fiber surface area per unit volume is large, there are many contact points between the active material and the fibers (particularly, surface porous plating fibers). That's why. The larger the total fiber surface area per unit volume is, the more excellent the effect is. ² / Cm ³ More preferably.
[0056]
The "total fiber surface area per unit volume" refers to a value obtained as follows.
(1) Specific surface area A (m ² / G).
(2) Based on the specific surface area A, the surface area Su per unit weight is calculated.
Su = A × W
Here, Su is the surface area (m ² / M ² ), A is the specific surface area (m ² / G) and W is the basis weight (g / m ² ).
(3) Based on the surface area Su per unit weight, the total fiber surface area Sv per unit volume is calculated.
Sv = Su / t
Here, Sv is the total fiber surface area per unit volume (cm ² / Cm ³ ), Su is the surface area per unit weight (cm ² / Cm ² ) And t indicate the thickness (cm) of the plated nonwoven fabric, respectively.
[0057]
The plated nonwoven fabric constituting the current collector of the present invention is composed of only plated fibers having a plated layer on the surface, including the surface porous plated fibers as described above. As plating fibers other than surface porous plating fibers, for example, fibers having pores other than the surface and having a plating layer on the surface, fibers having no pores at all and having a plating layer on the surface, etc. Can be included.
[0058]
The plated fibers that make up the plated non-woven fabric do not need to have a plating layer on the entire fiber surface, but the surface without the plating layer should not be exposed so that the current collecting property is excellent. preferable. For example, even if there is no plating layer on the surface of the contact point between the plated fibers that make up the plated nonwoven fabric, the surface of the contact is not exposed, so that the current collection performance of the plated nonwoven fabric (current collector) is hardly affected. Do not give. As described above, the plating fiber having no plating layer on the surface of the contact is likely to be formed when plating is performed after forming the nonwoven fabric.
[0059]
The porosity of the plated nonwoven fabric of the present invention is preferably 70% or more. This “porosity” refers to the percentage of pores with respect to the volume of the entire plated nonwoven fabric. When the porosity is 70% or more, the packing density of the active material synthesis paste can be increased, and as a result, the performance as a current collector for an electrode of a high capacity battery can be improved. On the other hand, if the porosity is too high, a significant decrease in strength is caused, so the porosity is preferably 80 to 98%.
[0060]
Preferably, the plated nonwoven fabric has a plurality of fine pores penetrating from one surface to the other surface. This is because, when a plurality of pores are scattered in the plated nonwoven fabric, these pores are also filled with the active material, and the filling amount of the active material is increased, so that the capacity of the battery can be increased. Such pores can be formed by punching, punching, or heat or laser processing, etc., formed by punching a non-woven fabric before plating, and locally dissolving or disappearing.
[0061]
The above is a method of manufacturing a plated nonwoven fabric, that is, a current collector, in which a nonwoven fabric is formed from nonporous fibers, and then a nonwoven fabric is formed, and in some cases, a hydrophilic treatment and a plating treatment are sequentially performed. The electric material is not limited to this manufacturing method. For example, (1) formation of surface porous fiber from non-porous fiber-hydrophilization treatment-formation of nonwoven fabric-plating treatment, and (2) formation of non-porous fiber to surface porous fiber Formation-hydrophilic treatment-plating treatment-formation of non-woven fabric, (3) formation of non-woven fabric using non-porous fiber-formation of surface porous fiber from non-porous fiber-hydrophilic treatment-plating treatment, (4) non-porous Of nonwoven fabric using porous fiber-hydrophilic treatment-formation of surface porous fiber from nonporous fiber-plating treatment, (5) formation of nonwoven fabric using nonporous fiber-hydrophilic treatment-plating treatment-nonporous Porous fiber to porous fiber (6) Hydrophilization treatment of non-porous fiber-formation of surface porous fiber from non-porous fiber-formation of nonwoven fabric-plating treatment, (7) hydrophilization treatment of non-porous fiber-from non-porous fiber Formation of surface porous fiber-plating treatment-formation of nonwoven fabric; (8) hydrophilic treatment of nonporous fiber-formation of nonwoven fabric-formation of surface porous fiber from nonporous fiber-plating treatment; (9) nonporous fiber (10) Hydrophilization treatment of non-porous fiber-plating treatment-formation of surface porous fiber from non-porous fiber-non-woven fabric (11) hydrophilic treatment of non-porous fibers-plating treatment-formation of nonwoven fabric-formation of surface porous fibers from non-porous fibers. Among these, the method of plating after forming the surface porous fiber from the non-porous fiber as in (1) to (4) or (6) to (8), the surface of the surface porous fiber Since the pores and the plating layer are firmly adhered to each other by the anchor effect, the peeling of the plating layer from the surface porous plating fiber can be suppressed, and a battery having low internal resistance can be manufactured. is there.
[0062]
Next, an alkaline secondary battery will be described with reference to FIGS. 2 and 3 as an example of a battery using the current collector according to the present invention.
[0063]
As shown in FIG. 2, the battery 101 is an alkaline secondary battery using a current collector made of a plated nonwoven fabric containing surface porous plated fibers, and includes a band-shaped positive electrode 102 and a band-shaped negative electrode 103 made of the current collector. A first separator 104a is interposed between the positive electrode 102 and the negative electrode 103, and a roll-shaped power generator 106 in which a second separator 104b is interposed is provided inside the positive electrode 102 (FIG. 2). The battery 101 includes a conductive battery case 107 that houses a power generator 106 and also serves as a negative electrode, and an enclosing plate 108 that seals the battery case 107 and also serves as a positive electrode.
[0064]
In the positive electrode 102, the above-described current collector 10 is formed in a belt shape, and a portion where a terminal is to be attached is crushed. Then, a positive electrode paste containing a positive electrode active material is filled in the voids of the entire current collector, and then dried and rolled. It is made by spot welding a nickel piece 102a as a current collecting external terminal to the crushed portion. In addition, the negative electrode 103 is formed in a strip shape with the above-described current collector, and after crushing a place where a terminal is to be attached, a gap of the entire current collector is filled with a negative electrode paste containing a negative electrode active material, and then dried and rolled. Then, a nickel piece (not shown) as a current collecting external terminal is spot-welded to the crushed portion. On the other hand, the separator 104 is formed in a strip shape from a porous sheet, and has a first separator 104a interposed between the positive electrode 102 and the negative electrode 103, and a second separator 104b laminated on the inner surface of the positive electrode 102. The first and second separators 104a and 104b are configured to prevent a short circuit between the positive electrode 102 and the negative electrode 103 and to hold the electrolyte.
[0065]
The conductive battery case 107 is formed in a cylindrical shape having a can bottom 107a, and the enclosing plate 108 is configured to close the opening at the upper end of the battery case 107. The battery case 107 is configured to be able to accommodate the power generator 106 such that the negative electrode 103 contacts the inner peripheral surface. Further, a projection 108a that forms a positive electrode terminal of the battery is formed at the center of the enclosing plate 108. In addition, a lower insulator 109a is interposed between the can bottom 107a and the power generator 106. The power generator 106 is inserted into the battery case 107 in which the lower insulator 109a is inserted, and an upper insulator 109b is disposed at the upper end of the power generator 106.
[0066]
A slit through which a nickel piece spot-welded to the negative electrode 103 can be inserted is formed in the lower insulator 109a, and a slit through which the nickel piece 102a spot-welded to the positive electrode 102 can be inserted is formed in the upper insulator 109b. The nickel piece spot-welded to the negative electrode 103 penetrates a slit formed in the lower insulator 109a and protrudes toward the can bottom 107a, and the nickel piece 102a spot-welded to the positive electrode 102 is a slit formed in the upper insulator 109b. And projecting toward the sealing plate 108 side. The nickel piece protruding from the slit of the lower insulator 109a is connected to the can bottom 107a, and the nickel piece 102a protruding from the slit of the upper insulator 109b is connected to the enclosing plate.
[0067]
With the upper insulator 109b inserted into the battery case 107, a ring-shaped constriction 107b is formed in the upper portion near the opening of the battery case 107, and then the electrolyte is injected. After that, the enclosing plate 108 to which the nickel piece 102a of the positive electrode 102 is connected is placed in the constricted portion 107b via a ring-shaped insulating packing 111. After that, the upper end edge of the battery case 107 is turned over, and the outer peripheral edge of the enclosing plate 108 is covered with the insulating packing 111 so that the encapsulating plate 108 is electrically insulated from the battery case 107, and the battery case is sealed by the enclosing plate 108. You.
[0068]
In the battery 101 configured as described above, the second separator 104b, the positive electrode 102, the first separator 104a, and the negative electrode 103 are sequentially stacked. In this stacked state, the power generator 106 is manufactured by winding the negative electrode 103 into a roll so that the negative electrode 103 is on the outside, but the current collector including the surface porous plating fiber is a conventional mesh made of nickel. Since the current collector is relatively flexible as compared to a skeleton current collector, the positive electrode 102 and the negative electrode 103 using the current collector are also relatively flexible, and are relatively easy to be wound into a roll. The battery 101 itself can be easily assembled.
[0069]
In addition, since the current collector containing the surface porous plating fibers has excellent current collecting properties, the amount of fibers constituting the current collector can be reduced, and the porosity of the current collector can be increased. Since the filling amount can be increased, a high-capacity battery can be manufactured.
[0070]
In the above-described embodiment, the battery in which the power generator 106 wound in a roll shape is inserted into the cylindrical battery case 107 has been described. However, the battery case may be a rectangular tube. May be formed by winding a positive electrode 102 and a negative electrode 103 in a spiral angle as shown in FIG. 4 or by bending and laminating them in a bellows shape as shown in FIG.
[0071]
Hereinafter, examples of the current collector of the present invention will be described, but the present invention is not limited to the following examples.
[0072]
【Example】
(Example 1)
A core-sheath composite fiber having a core component of polypropylene, a sheath component of high-density polyethylene (melting point: 135 ° C.), a fineness of 11 dtex (fiber diameter: 39 μm) and a fiber length of 5 mm (the sheath component covers the entire fiber surface) The fiber web was formed by a wet papermaking method using a slurry in which 100% by weight of the occupied cross section was circular. This fiber web was heat-treated with a drier set at a temperature of 135 ° C. to fuse the sheath component of the core-sheath composite fiber, and the basis weight was 120 g / cm. ² To produce a nonwoven fabric having a thickness of 1.5 mm.
[0073]
Next, this nonwoven fabric is subjected to sulfonation treatment by immersing it in fuming sulfuric acid at a temperature of 80 ° C. ^-3 Was produced.
[0074]
Next, sodium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was pulverized with a pulverizer to obtain sodium chloride fine particles having an average primary particle diameter of 8.0 μm.
[0075]
Next, 100 g of the sodium chloride fine particles were placed in a petri dish having a diameter of 15 cm, heated in a dryer set at a temperature of 140 ° C. for 30 minutes or more with the lid covered, and immediately after the petri dish was taken out from the dryer, the above sulfonated nonwoven fabric ( (10 cm square) was placed in a Petri dish, and the Petri dish was immediately vibrated for 30 seconds to fix sodium chloride fine particles on the entire sulfonated nonwoven fabric, thereby producing a sodium chloride fine particle-fixed sulfonated nonwoven fabric. Thereafter, the sodium chloride fine particles were removed by washing the sodium chloride fine particle-fixed sulfonated nonwoven fabric with water to produce a sulfonated nonwoven fabric composed of surface porous fibers having pores formed only on the surface.
[0076]
Next, the sulfonated nonwoven fabric composed of surface porous fibers was charged into a beaker into which the refining agent had been injected, and the sulfonated nonwoven fabric was stirred with a stirrer so that the refining agent was permeated, and then the sulfonated nonwoven fabric was washed with water.
[0077]
Next, the sulfonated nonwoven fabric is put into a beaker into which an aqueous solution containing 10 g / L of stannous chloride and 20 mL / L of hydrochloric acid has been injected, and the sulfonated nonwoven fabric is stirred by a stirrer so that the aqueous solution permeates. The nonwoven fabric was washed with water. Thereafter, the sulfonated nonwoven fabric is put into a beaker into which an aqueous solution containing 1 g / L of palladium chloride and 20 mL / L of hydrochloric acid has been injected, and the sulfonated nonwoven fabric is stirred by a stirrer so that the aqueous solution permeates the sulfonated nonwoven fabric. Was catalyzed.
[0078]
Then, after washing the catalyzed sulfonated nonwoven fabric with water, an electroless nickel plating solution having various concentrations of nickel sulfate 18 g / L, sodium citrate 10 g / L, hydrated hydrazine 50 mL / L, and 25% ammonia water 100 mL / L. Was poured into a beaker, and the catalyzed sulfonated nonwoven fabric was stirred for 1 hour with a stirrer so as to allow the plating solution to pass therethrough while heating to a temperature of 80 ° C., thereby performing electroless plating.
[0079]
Thereafter, the sulfonated nonwoven fabric that has undergone the plating step is taken out, washed with water, and further dried. ² , Thickness: 1.5 mm, porosity: 91%, total fiber surface area per unit volume of plated nonwoven fabric: 600 cm ² / Cm ³ , Semi-spherical shape, shape of aperture: substantially polygonal, average diameter of aperture: 5.0 μm, major axis of aperture / minor axis of aperture = 1.2, average depth of pore: 3.0 μm, pore length: 1.4 times the opening width, number of pores: 500 / 10,000 μm ² ) Got. The plating ratio (R) is a value obtained by the following equation.
R = {(Wa−Wb) / Wa} × 100
Here, R means the plating ratio (%), and Wa is the weight after plating, that is, the basis weight of the current collector (g / m2). ² ), And Wb is the weight before plating, that is, the basis weight (g / m2) of the sulfonated nonwoven fabric composed of surface porous fibers. ² ).
[0080]
(Comparative Example 1)
The sulfonated nonwoven fabric produced in the same manner as in Example 1 was subjected to plating treatment without subjecting the core-sheath type composite fiber to surface porosity treatment, and the plating ratio was 50%, that is, a current collector (basis weight: 240 g). / M ² , Thickness: 1.5 mm, porosity: 90%, total fiber surface area per unit volume of plated nonwoven fabric: 400 cm ² / Cm ³ ) Got.
[0081]
(Example 2)
A sulfonated nonwoven fabric made of surface porous fibers was produced in exactly the same manner as in Example 1 except that the vibration time in the petri dish was set to 5 seconds.
[0082]
Next, the sulfonated nonwoven fabric made of the surface porous fiber was subjected to plating treatment in exactly the same manner as in Example 1, and the plated nonwoven fabric having a plating ratio of 50%, that is, a current collector (basis weight: 240 g / m2) ² , Thickness: 1.5 mm, porosity: 91%, total fiber surface area per unit volume of plated nonwoven fabric: 500 cm ² / Cm ³ , Semi-spherical shape, shape of aperture: substantially polygonal, average diameter of aperture: 5.0 μm, major axis of aperture / minor axis of aperture = 1.2, average depth of pore: 3.0 μm, pore length: 1.4 times the opening width, number of pores: 400 / 10,000 μm ² ) Got.
[0083]
(Comparative Example 2)
A core-sheath type composite fiber having a core component of polypropylene, a sheath component of high-density polyethylene (melting point: 135 ° C.), a fineness of 6.6 dtex (fiber diameter: 30 μm) and a fiber length of 5 mm (sheath the entire fiber surface) A fiber web was formed by a wet papermaking method using a slurry in which 100% by weight of the components occupied (cross-sectional shape: circular) was dispersed. This fiber web was heat-treated with a dryer set at a temperature of 135 ° C. to fuse the sheath component of the core-sheath type composite fiber to give a basis weight of 120 g / cm. ² To produce a non-woven fabric having a thickness of 1 mm.
[0084]
Next, this nonwoven fabric is subjected to sulfonation treatment by immersing it in fuming sulfuric acid at a temperature of 80 ° C. ^-3 Was produced.
[0085]
Next, this sulfonated nonwoven fabric was plated in the same manner as in Example 1 without performing the surface-poration treatment of the core-sheath type conjugate fiber, and the plated nonwoven fabric having a plating ratio of 50%, that is, a current collector (basis weight: 240 g / m ² , Thickness: 1 mm, porosity: 83%, total fiber surface area per unit volume of plated nonwoven fabric: 600 cm ² / Cm ³ ) Got.
[0086]
(Comparative Example 3)
After spinning the fiber by mixing the solid particles, a whole porous fiber (fineness: 11 dtex, fiber length: 5 mm) having fine pores on the fiber surface and inside was prepared by extracting and removing the solid particle.
[0087]
Next, a core-in-sheath type composite fiber (fineness: 2.2 dtex, fiber length: 10 mm), 20 mass, in which the whole porous fiber 80 mass%, the core component is made of polypropylene, and the sheath component is made of high-density polyethylene (melting point: 135 ° C.). % Was dispersed to form a fiber web by a wet papermaking method. This fiber web was heat-treated with a drier set at a temperature of 135 ° C. to fuse the sheath component of the core-sheath composite fiber, and the basis weight was 120 g / cm. ² To produce a non-woven fabric having a thickness of 1.2 mm.
[0088]
Next, this nonwoven fabric was subjected to a sulfonation treatment and a plating treatment in the same manner as in Example 1, and the plating ratio was 50%, that is, a current collector (basis weight: 240 g / m2). ² , Thickness: 1.2 mm, porosity: 85%, total fiber surface area per unit volume of plated nonwoven fabric: 500 cm ² / Cm ³ , Sponge-like, shape of aperture: substantially circular, average diameter of aperture: 1 μm, major axis of aperture / minor axis of aperture = 1.1, average depth of pore: more than 15 μm, fine Pore length: more than 3 times the opening width, number of pores: 8000/10000 μm ² ) Got.
[0089]
(Peeling test)
After sticking an adhesive tape (Nitto 31B, manufactured by Nitto Denko Corporation) to each current collector, pressing strongly with a finger, pulling one end of the adhesive tape, separating the adhesive tape from the current collector, and removing nickel from the current collector. The presence or absence of peeling of the plating was observed. The results were as shown in Table 1.
[0090]
(Measurement of utilization rate)
An AA (AA) type battery (theoretical capacity of the batteries of Examples 1 to 3 and Comparative Example 1 was 1200 mAh, using the current collectors of Examples and Comparative Examples for the positive electrode and foamed nickel for the negative electrode, respectively. The theoretical capacity of the battery of Example 2 was 950 mAh, and the theoretical capacity of the battery of Comparative Example 3 was 1000 mAh).
[0091]
Next, the battery was activated by charging and discharging at a temperature of 20 ° C. and 0.1 C (120 mAh), respectively, and further charged and discharged at 0.1 C for 5 cycles. The rate was calculated.
[0092]
Next, charging and discharging were performed for 5 cycles at a test current of 4.0 C (4800 mAh), and the 4.0 C utilization was calculated from the average of the discharge capacity for 5 cycles. The utilization rate (U, unit:%) was calculated by the following equation.
U = (C ₅ / Ct) × 100
Here, U represents the utilization rate (%), and C ₅ Represents the average (mAh) of the discharge capacity of 5 cycles, and Ct represents the theoretical capacity (mAh).
[0093]
[Table 1]

[0094]
As is clear from the results of the theoretical capacity of the battery shown in Table 1, the current collector containing the surface perforated plating fiber of the present invention was able to increase the capacity and was excellent in current collection performance. Further, as is apparent from the results of the 4.0C utilization rate, the current collector of the present invention was excellent in current collection performance in high-rate discharge.
[0095]
【The invention's effect】
The current collecting material of the present invention has excellent current collecting properties. Also, a high-capacity battery can be manufactured.
[0096]
The battery of the present invention is excellent in current collection performance and can be a high capacity battery.
[Brief description of the drawings]
FIG. 1A is a schematic cross-sectional image of a surface porous plating fiber of the present invention.
(B) Cross-sectional image pattern diagram of another surface porous plating fiber of the present invention
(C) A schematic cross-sectional image of the surface porous plated fiber of the present invention in the fiber axis direction.
(D) Cross-sectional image schematic diagram of another surface porous plated fiber of the present invention in the fiber axis direction
FIG. 2 is a partially cutaway perspective view of the alkaline secondary battery of the present invention.
FIG. 3 is a sectional view taken along line AA of FIG. 2 in which a current collector is wound in a spiral circle.
FIG. 4 is a sectional view corresponding to FIG. 3 in which a current collector is wound in a spiral angle;
FIG. 5 is a cross-sectional view corresponding to FIG. 3 in which current collectors are bent and stacked in a bellows shape;
[Explanation of symbols]
10 Surface porous plating fiber
11 pores
12 Fiber surface
13 Opening
101 Battery
102 positive electrode
102a Nickel piece
103 Negative electrode
104 separator
104a first separator
104b second separator
106 generator
107 Battery case
107a Can bottom
107b Constriction
108 sealing plate
108a protrusion
109a Lower insulator
109b Upper insulator

Claims (6)

For a battery, characterized in that it is formed of a plated non-woven fabric that is formed only of plated fibers having a plated layer on the surface, and has pores formed only on the surface and includes surface porous plated fibers having a plated layer on the surface. Current collector. 2. The current collector for a battery according to claim 1, wherein the shape of the opening of the pore is substantially circular or substantially polygonal, and the average diameter of the opening is 0.5 to 15 [mu] m. The current collector for a battery according to claim 1, wherein an average depth of the pores is 0.1 to 15 μm. 4. The current collector for a battery according to claim 1, wherein the number of the pores is 10 to 55000 per 10,000 μm ^{2 of the} fiber surface. 5. It said fibers the total surface area per unit volume of the plating nonwoven, characterized in that it is 500 cm 2 ^/ cm ³ or more, battery current collector according to any one of claims 1 to 4. A battery using the battery current collector according to claim 1.

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