JP4903959B2 - Battery current collector and battery using the same - Google Patents

Description

この表１において、めっき断面積が２０μｍ²〜１３０μｍ²である集電材を実施例１〜４とし、この範囲を外れるめっき断面積の集電材を比較例１〜４として示した。これらの集電材について、電池試験を行った。測定方法は、次の通りである。
【００５２】
まず、表１中、活物質の充填密度（ｇ／ｃｍ³）は、活物質である水酸化ニッケル（Ｎｉ（ＯＨ）₂）を充填した後の集電材重量Ｗ１（ｇ）を測定し、この重量から活物質充填前の重量Ｗ（ｇ）を引き、活物質充填量（Ｗ１−Ｗ）を計算する。次に、活物質を充填した後の集電材の厚みＴ（ｃｍ）及び面積Ａ（ｃｍ²）を測定する。これらの測定結果から、活物質の充填密度は、充填密度（ｇ／ｃｍ³）＝（Ｗ１−Ｗ）／（Ａ×Ｔ）として求めた。
【００５３】
また、不織布の繊維比重（ポリプロピレン／ポリエチレン）（ｇ／ｃｍ³）は０．９４であり、ニッケル金属の比重（ｇ／ｃｍ³）は８．９であった。これらの値から、めっき後の繊維比重（ＳＧ）（ｇ／ｃｍ³）は、（集電材重量（ｇ））／｛（ニッケル重量÷８．９）＋（不織布重量÷０．９４）｝から求めた。
【００５４】
次に、表１中、集電材の空隙率（％）は、集電材の厚みｔ（μｍ）、目付Ｗ（ｇ／ｍ²）から、空隙率（％）＝｛１−Ｗ／（ｔ×ＳＧ）｝×１００により求めた。また、利用率（％）は、次のようにして測定した。すなわち、正極に実施例及び比較例の集電材を使用し、負極に発泡ニッケルを使用して、ＡＡ（単３）型電池（容量１２００ｍＡｈ）を作製し、２０℃、０．１Ｃ充放電で電池を活性化させた。試験電流を変化させて、５サイクルずつ充放電を行った。各試験レート０．１Ｃ〜３Ｃについての試験電流は、０．１Ｃについて０．１×１２００（ｍＡｈ）、１Ｃについて１×１２００（ｍＡｈ）、２Ｃについて２×１２００（ｍＡｈ）、３Ｃについて３×１２００（ｍＡｈ）である。利用率（％）は、利用率（％）＝｛放電容量（５回の測定の平均値）÷１２００｝×１００により求めた。めっき比率（％）は、めっき比率（％）＝｛ニッケル重量（ｇ）÷集電材重量Ｗ（ｇ）｝×１００により求めた。
【００５５】
表１から明らかなように、めっき断面積が１３０μｍ²を超えると、めっき後の繊維が太くなり、空隙率が下がるため、活物質の充填量が不十分となる。また、めっき断面積が２０μｍ²未満であると、めっき量が少なく表面抵抗が高いため、ハイレート充放電で充分な容量が得られないことが判った。これに対して、めっき不織布繊維表面のめっき断面積が２０μｍ²〜１３０μｍ²の範囲であると、めっき膜の表面抵抗が低く、活物質を充分に充填でき、電池を高容量化することができ、かつハイレート充放電が可能な電池が得られることが判った。
【００５６】
【発明の効果】
以上述べたように、請求項１の発明によれば、めっき不織布繊維表面のめっき断面積が２０μｍ²〜１３０μｍ²であるので、めっき膜の表面抵抗が低く、活物質を充分に充填でき、電池を高容量化することができ、かつハイレート充放電が可能な電池を製造できるという効果を奏する。
【００５７】
請求項２の発明によれば、不織布が親水化処理されているので、不織布の繊維のめっき膜との密着度が上昇し、めっき膜の表面抵抗が低下するため、ハイレート充放電が可能となるという効果を奏する。
【００５８】
請求項３の発明によれば、不織布の構成繊維として、繊度が１．５ｄｔｅｘ以上の繊維を含んでいるので、空隙率が増大して活物質の充填量を増加できると共に、めっき量を調節して容易に所定のめっき断面積が得られるという効果を奏する。
【００５９】
請求項４の発明によれば、電池が請求項１〜３のいずれか１項に記載された集電材を用いるので、高容量化され、かつハイレート充放電が可能な電池が得られるという効果を奏する。
【図面の簡単な説明】
【図１】不織布とめっき膜を含む本発明の集電材の局部拡大図である。
【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である。
【図３】集電体が渦巻き円状に巻回された図２のＡ−Ａ線断面図である。
【図４】集電体が渦巻き角状に巻回された図３に対応する断面図である。
【図５】集電体が蛇腹状に屈曲積層された図３に対応する断面図である。
【符号の説明】
１０…集電材、１１…不織布、１１ａ…接触点、１２…めっき膜、１２ａ…無電解めっき膜、１２ｂ…電解めっき膜、１０１…アルカリ二次電池、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、１０８…突起、１０９ａ…ロア絶縁体、１０９ｂ…アッパ絶縁体。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a battery current collector and a battery using the same, and more particularly to a battery current collector obtained by plating a non-woven fabric with a predetermined plating cross-sectional area and a battery using the same.
[0002]
[Prior art]
Conventionally, batteries, particularly alkaline secondary batteries, are highly reliable and can be reduced in size and weight, and thus are frequently used as power sources for various devices ranging from portable devices to large industrial facilities. In most of the alkaline secondary batteries, a nickel hydroxide electrode is used as the 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 collector that shares a current collecting function. As the current collector in that case, a sintered nickel plate or a punched nickel plate obtained by sintering nickel powder has been widely used. The capacity of the battery is determined by the amount of the active material to be filled in the voids of the nickel plate, and the filling 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 uses a punched nickel plate as a base material, and this base material has a low porosity of 75 to 80% and has a low nickel content in the nitrate solution. It is necessary to repeat the impregnation and neutralization filling cycles several times or more, and as the filling cycle is repeated, the penetration of the nitrate solution into the nickel plate deteriorates, so that it is difficult to fill the active material with high density. Therefore, in recent years, in order to increase the packing density of the active material of the current collector in response to the demand for smaller and higher capacity batteries, the three-dimensional can increase the porosity and hence the packing density of the active material. A current collector made of a net-like structure is used.
[0004]
As a current collector of this three-dimensional network structure, for example, as described in JP-A-8-329956, a predetermined amount of nickel plating is applied to a non-woven fabric made of organic fibers, and the non-woven fabric is thermally decomposed and removed. There is known a current collector made of a three-dimensional network structure in which only the surface of the nonwoven fabric can exhibit conductivity.
[0005]
A current collector for an alkaline secondary battery including a nonwoven fabric and a nickel plating film formed on the surface of the nonwoven fabric is also known.
[0006]
[Problems to be solved by the invention]
However, the non-woven fabric made from the organic fibers used in the current collector disclosed in JP-A-8-329956 has a large amount of nickel plating applied to the surface, so that the porosity is low and the pore diameter is small. Therefore, there is a problem that it is difficult to sufficiently fill the battery active material and it is difficult to increase the capacity of the battery.
[0007]
In addition, current collectors in which a nickel plating film is formed on the surface of a conventional nonwoven fabric have a problem in that surface resistance is high and high-rate charge / discharge is difficult.
[0008]
The present invention has been made in order to solve such a conventional problem, and uses a current collector capable of increasing the capacity of the battery and manufacturing a battery capable of high-rate charge / discharge and the same. An object is to provide a battery.
[0009]
[Means for Solving the Problems]
The invention according to claim 1 of the present invention is a battery current collector comprising a non-woven fabric and a plating film formed on the surface of the non-woven fabric, wherein the plating cross-sectional area of the plated non-woven fiber surface on which the plating film is formed But 40 μm ² ~ 120 μm ² A battery current collector.
[0010]
The invention according to claim 2 is characterized in that the nonwoven fabric is hydrophilized.
[0011]
The invention according to claim 3 is characterized in that the constituent fibers of the nonwoven fabric include fibers having a fineness of 1.5 dtex or more.
[0012]
The invention according to claim 4 is a battery characterized by using the current collector described in any one of claims 1 to 3.
[0013]
According to invention of Claim 1, the plating cross-sectional area of the plating nonwoven fabric fiber surface is 40 μm ² ~ 120 μm ² Therefore, the surface resistance of the plating film is low, the active material can be sufficiently filled, the battery can be increased in capacity, and a battery capable of high rate charge / discharge can be manufactured.
[0014]
According to the invention of claim 2, since the non-woven fabric is hydrophilized, the degree of adhesion of the non-woven fabric fibers to the plating film is increased and the surface resistance of the plating film is decreased, so that high-rate charge / discharge is possible. .
[0015]
According to the invention of claim 3, since the non-woven fabric includes fibers having a fineness of 1.5 dtex or more, the porosity can be increased to increase the filling amount of the active material, and the plating amount can be adjusted. Thus, a predetermined plating cross-sectional area can be easily obtained.
[0016]
According to the invention of claim 4, since the battery uses the current collector described in any one of claims 1 to 3, a battery having a high capacity and capable of high-rate charge / discharge is obtained.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0018]
As shown in FIG. 1, the current collector 10 of the present invention has a nonwoven fabric 11 and a plating film 12 formed on the surface of the nonwoven fabric 11. Moreover, the plating cross-sectional area of the surface of the plating nonwoven fabric on which the plating film 12 is formed is 20 μm. ² ~ 130μm ² Range. The current collector according to the present invention can be used for various primary batteries and secondary batteries, for example, alkaline batteries and lithium batteries, and an alkaline secondary battery will be described as an example of a desirable battery.
[0019]
First, the nonwoven fabric 11 is comprised by any one or both of a polyolefin-type fiber or a polyamide resin-type fiber. Examples of the resin component of the polyolefin-based fiber include polyethylene, polypropylene, polymethylpentene, ethylene-propylene copolymer, ethylene-butene-propylene copolymer, or ethylene-vinyl alcohol copolymer. Polyolefin fibers include those resins. It is preferable to include one or more components. Examples of the resin component of the polyamide resin fiber include nylon 6, nylon 66, nylon 12, or a copolymer of nylon 6 and nylon 12, and the polyamide resin fiber includes one or more of these resin components. It is preferable to include.
[0020]
The nonwoven fabric 11 composed of one or both of polyolefin fibers and polyamide resin fibers is used because of the fact that polyolefin fibers and polyamide resin fibers themselves are already used as battery separators. This is because polyolefin fibers and polyamide resin fibers do not dissolve even when contacted with a 35% by weight aqueous KOH solution, so there is no change in physical properties, excellent alkali resistance, and they can be purchased at a very low price and are highly versatile. .
[0021]
In the case of polyolefin fibers, a polyethylene resin or polypropylene resin excellent in alkali resistance and acid resistance is particularly preferable. Polyolefin fibers may be polypropylene resin alone, polyethylene resin alone, or a combination of these resins. In particular, a core-sheath type composite fiber in which the periphery of polypropylene (core) is covered with polyethylene (sheath) is preferable because it can satisfy both alkali resistance and strength characteristics at the same time. Although FIG. 1 shows polyolefin fibers or polyamide fibers, the present invention is not limited thereto.
[0022]
Although it does not specifically limit as a fiber which comprises this nonwoven fabric 11, It is preferable to use the fiber which has a crimp. When the nonwoven fabric 11 includes fibers having crimps, the nonwoven fabric 11 becomes bulky, so that the void volume is increased and a large amount of active material can be filled, resulting in a high capacity battery. Moreover, since the average pore diameter is increased, the active material can be easily filled. The number of the crimped fibers is preferably 3 / inch or more, and more preferably 5 / inch or more. Further, in order to maintain an appropriate porosity, it is preferable that the fibers having the crimps are mixed in the nonwoven fabric in an amount of 5% by weight or more, more preferably 20% by weight or more. More preferably, they are mixed in a ratio of not less than% by weight. This crimped fiber may be mechanically imparted with crimping, or may be a fiber that causes crimping by heat. Examples of the fibers that are crimped by heat include side-by-side fibers made of two kinds of resins having different shrinkage temperatures, and eccentric core-sheath fibers.
[0023]
The nonwoven fabric 11 can be produced by (1) the card method or air-lay method, or (2) the dry method such as the melt blow method or spunbond method for continuously forming the sheet from the spinning state, or (3) the fiber is water. After a fiber web is formed by a wet method or the like that is dispersed in a paper and then papered, the fibers can be appropriately bonded together. In particular, a nonwoven fabric produced from a fiber web obtained by a wet method has a smaller variation in basis weight and thickness than a nonwoven fabric produced from a fiber web obtained by a dry method, so that a uniform current collector can be obtained. it can. For this reason, when this current collector is used, an electrode having a uniform thickness is formed. When the electrode is wound, a pole group having excellent adhesion can be formed, and as a result, a battery having excellent charge / discharge characteristics can be obtained.
[0024]
Examples of the fiber web bonding method include a method of improving strength characteristics by performing an entanglement treatment or a heat treatment. As the entanglement process, for example, a water entanglement process that shocks a very fine high-pressure water jet, an entanglement process using a needle punch, or the like can be employed. When the entanglement treatment is performed on the fiber web, the fibers are entangled with each other, the number of contact points 11a between the fibers is increased, the strength characteristics thereof are improved, and the porosity can be adjusted to an appropriate value. The heat treatment is performed to enhance the overall strength characteristics by locally fusing the fibers at the contact points 11a of each other. However, if heat treatment is performed at a temperature equal to or higher than the thermal decomposition temperature of the fiber, the fiber is thermally decomposed and disappears. Therefore, it is necessary to set the treatment temperature to be lower than the thermal decomposition temperature of the fiber.
[0025]
The temperature of the heat treatment is set within a temperature range that is lower than the thermal decomposition temperature of the fiber and 30 ° C. higher than the melting point from the temperature at which the fiber is softened. Therefore, the strength of the obtained non-woven fabric is low, and buckling or the like starts to occur when the active material synthetic paste is filled. On the other hand, if the temperature is too high, melting of the fibers proceeds and the porosity decreases, which also reduces the packing density of the active material synthetic paste. For this reason, when the above-described core-sheath type composite fiber in which the periphery of polypropylene is covered with polyethylene is used as the fiber, the temperature of the heat treatment is preferably 110 to 140 ° C. Although the entanglement treatment and the heat treatment may be performed independently, it is preferable to perform the heat treatment after the entanglement treatment because the strength characteristics of the obtained nonwoven fabric are remarkably improved.
[0026]
The nonwoven fabric 11 preferably has a porosity of 70% or more. The porosity in this case refers to the percentage of pores with respect to the entire volume of the nonwoven fabric. When the porosity is less than 70%, the strength characteristics of the obtained nonwoven fabric 11 are improved, but the packing density of the active material synthetic paste is lowered, and as a result, the performance as the current collector 10 for electrodes of a high capacity battery is reduced. Because it becomes like this. On the other hand, if the porosity is too high, a significant decrease in strength is caused. Therefore, the porosity is preferably set to 80 to 98%.
[0027]
The current collector 10 uses a nonwoven fabric 11 composed of one or both of the above-described polyolefin fibers or polyamide resin fibers. Preferably, the nonwoven fabric 11 may be hydrophilized, thereby increasing the adhesion between the fibers of the nonwoven fabric and the plating film and reducing the surface resistance of the plating film, thereby enabling high-rate charge / discharge. The hydrophilic treatment is performed by sulfonation treatment, fluorine gas treatment or vinyl monomer graft treatment, surfactant treatment, hydrophilic resin application treatment and discharge treatment. The current collector 10 is made by plating the non-woven fabric 11 that has been hydrophilized.
[0028]
In general, polyolefin-based materials such as polypropylene and polyamide-based materials have poor affinity with the plating solution and have poor adhesion between the fiber surface and the plating film. On the other hand, the hydrophilic treatment improves the affinity of the plating solution with the fiber surface and binds strongly to nickel ions, improving conductivity and improving the adhesion with the metal plating formed on the fiber surface. Is planned.
[0029]
Examples of the hydrophilization treatment include sulfonation treatment, fluorine gas treatment, vinyl monomer graft polymerization, surfactant treatment, discharge treatment or hydrophilic resin application treatment. In particular, sulfonation treatment, fluorine gas treatment, or vinyl monomer grafting treatment is preferable in the absence of dropout of the plating film and increase in surface resistance in an aqueous solution of 20 to 35 wt% KOH, which is an electrolytic solution used in batteries. .
[0030]
Although it does not specifically limit as a sulfonation process, For example, there exists a process by immersion in fuming sulfuric acid, a sulfuric acid, sulfur trioxide, a chlorosulfuric acid, or a sulfuryl chloride. Among these, sulfonation treatment with fuming sulfuric acid is preferable because it has high reactivity and can be easily sulfonated. The fluorine gas treatment is not particularly limited, but is selected from, for example, fluorine gas diluted with an inert gas (for example, nitrogen gas, argon gas, etc.), oxygen gas, carbon dioxide gas, and sulfur dioxide gas. A treatment by contact with a mixed gas with at least one kind of gas can be mentioned. In addition, after making sulfur dioxide gas adhere beforehand to a nonwoven fabric, the method of making it contact with fluorine gas is a more efficient and permanent hydrophilization method. The grafting treatment of the vinyl monomer is not particularly limited. For example, at least one graft polymerization solution selected from acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, vinyl pyridine, or styrene is used. A treatment of impregnating a nonwoven fabric and irradiating with ultraviolet rays can be given. Among these, acrylic acid is preferable because it does not drop off the plating film or increase the surface resistance in a KOH aqueous solution that is an electrolytic solution for a long time.
[0031]
The hydrophilized nonwoven fabric thus obtained is subjected to a plating treatment. The plating treatment is preferably an electroless plating method. If necessary, an electrolytic plating film 12b is further formed on the electroless plating film 12a formed by the electroless plating method, and the surface of the nonwoven fabric 11 is formed. Is coated with a plating film 12. The metal to be plated is typically nickel, but various metals such as copper, gold, and aluminum can be used depending on the battery to be used.
[0032]
In the present invention, the plating cross-sectional area of the surface of the plating nonwoven fabric on which the plating film 12 is formed is 20 μm. ² ~ 130μm ² It is desirable to be in the range. Plating cross section is 20μm ² If it is less than 30 μm, the surface resistance of the plating film 12 becomes high and high-rate charge / discharge becomes difficult. ² More preferably, 40 μm ² The above is more preferable. Also, the plating cross section is 130μm ² Exceeding the thickness, the fiber becomes thick, the porosity decreases, the amount of active material filling decreases, and it becomes difficult to increase the capacity of the battery. ² More preferably, it is 110 μm ² More preferably, it is as follows.
[0033]
In order to obtain such a plating cross-sectional area, it is desirable that the fibers constituting the nonwoven fabric that is the basis of the plated nonwoven fabric include fibers having a fineness of 1.5 dtex or more. More desirably, the fiber contains 2.5 dtex or more, and most preferably contains 4 dtex or more. The upper limit is not particularly limited, but fibers having a fineness of about 30 dtex are suitable. By using such a comparatively thick fiber, the space | interval of adjacent fibers becomes large, the porosity can increase and the filling amount of an active material can be increased. Moreover, a desired plating cross-sectional area can be easily obtained. Such relatively thick fibers are preferably contained in the nonwoven fabric in an amount of 10 mass% or more, more preferably 20 mass% or more.
[0034]
Here, the electroless plating method is specifically divided into a catalyst imparting step and an electroless plating step. The catalyst-imparting 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 with a hydrochloric acid solution of palladium chloride containing an amino group of a curing agent. However, the former method is preferable because it is most excellent in the uniformity of the plating film thickness. The electroless plating process is a method of reducing nickel with a reducing agent in an aqueous solution generally containing nickel salts such as nickel nitrate, nickel chloride, nickel sulfate and the like. , Buffers, stabilizers and the like are added. In particular, in order to obtain a highly pure nickel film, a method using a hydrazine derivative such as hydrated hydrazine, hydrazine sulfate, or hydrazine oxide as a reducing agent is preferable. The properties of the non-woven fabric when electroless plating is performed using a cheese dyeing machine in the state of continuous plating from a catalyst application tank to a plating tank while winding up a continuous length, or in the state of winding in a roll shape. For example, a method of forcibly circulating the liquid and plating may be used. In the treatment in the state of being wound in a roll shape, only the catalyst application step or the electroless plating step may be performed, or both steps may be performed in the state of being wound in a roll shape.
[0035]
If necessary, an electrolytic plating film 12b is further formed. The electrolytic plating method is performed using a plating bath. Known plating baths include watt baths, chloride baths, and sulfamic acid baths. In some cases, additives such as a pH buffer and an interface buffer may be used. The electroless plated film 12b is formed on the electroless plated film 12a by connecting a non-woven fabric electrolessly plated in the bath to the cathode and a nickel counter electrode to the anode and applying a direct current or pulse intermittent current. .
[0036]
Since the current collector made in this way uses a nonwoven fabric 11 composed of either or both of polyolefin fibers and polyamide resin fibers that have been used as battery separators, it is relatively reliable. High nature. Further, since this nonwoven fabric 11 is subjected to a hydrophilic treatment (particularly sulfonation treatment, fluorine gas treatment or vinyl monomer graft treatment), the affinity of the nonwoven fabric with the plating solution is improved, and this hydrophilic treated nonwoven fabric is nickel-plated. Since it processes, the nonwoven fabric 11 will couple | bond with a nickel ion firmly. As a result, the current collector 10 with improved conductivity and improved adhesion between the metal plating formed on the fiber surface can be obtained.
[0037]
The nonwoven fabric is preferably interspersed with a plurality of pores penetrating from one surface to the other surface. If a plurality of pores are interspersed in the nonwoven fabric, the active material is also filled into these pores, so that the amount of active material filling increases and the capacity of batteries, particularly alkaline secondary batteries, is increased. Can do. The formation of the non-woven fabric with pores is preferably formed by so-called punching which forms a plurality of pores by punching, but may be formed by locally dissolving or eliminating the non-woven fabric by heat, laser processing, or the like. .
[0038]
Next, as an example of a battery using the current collector according to the present invention, an alkaline secondary battery will be described with reference to the drawings.
[0039]
As shown in FIG. 2, the battery 101 is an alkaline secondary battery using a current collector obtained by applying nickel plating to a nonwoven fabric subjected to a hydrophilic treatment (for example, sulfonation treatment, fluorine gas treatment, or vinyl monomer graft treatment), A strip-like positive electrode 102 and a strip-like negative electrode 103 made of the current collector are provided. 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 inside the positive electrode 102 is provided (FIG. 2). The battery 101 includes a conductive battery case 107 that houses the power generator 106 and also serves as a negative electrode, and an encapsulating plate 108 that seals the case 107 and also serves as a positive electrode.
[0040]
The positive electrode 102 is formed by forming the above-described current collector into a strip shape, crushing a portion to which a terminal is attached, filling a gap in the entire current collector with a positive electrode paste containing a positive electrode active material, and then drying and rolling. And it is made by spot welding the nickel piece 102a as an external terminal for current collection in the crushed location. Further, the negative electrode 103 is formed by forming the above-described current collector into a strip shape, crushing a portion to which a terminal is attached, filling a gap portion of the entire current collector with a negative electrode paste containing a negative electrode active material, and then drying and rolling. And it is made by spot-welding a nickel piece (not shown) as a current collecting external terminal to the crushed portion. On the other hand, the separator 104 is formed in a band shape by a porous sheet, and includes a first separator 104 a interposed between the positive electrode 102 and the negative electrode 103, and a second separator 104 b stacked 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 hold the electrolyte.
[0041]
The conductive battery case 107 is formed in a cylindrical shape having a can bottom 107 a, and the enclosing plate 108 is configured to close the opening at the upper end of the battery case 107. The battery case 107b is configured to accommodate the power generator 106 so that the negative electrode 103 is in contact with the inner peripheral surface thereof. In addition, a protrusion 108a that forms the positive terminal of the battery is formed at the center of the encapsulating plate 108. Further, a lower insulator 109a is interposed between the can bottom 107a and the power generator 106. The power generator 106 is inserted into a battery case 107 in which a lower insulator 109 a is inserted, and an upper insulator 109 b is disposed at the upper end of the power generator 106.
[0042]
The lower insulator 109 a is formed with a slit through which the nickel piece spot welded to the negative electrode 103 can be inserted, and the upper insulator 109 b is formed with a slit through which the nickel piece 102 a spot welded to the positive electrode 102 can be inserted. The nickel piece spot-welded to the negative electrode 103 is inserted through the 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 formed in the slit formed in the upper insulator 109b. And is configured to protrude to 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 sealing plate 108.
[0043]
In a state where the upper insulator 109b is inserted into the battery case 107, a sealing plate 108 in which a ring-shaped constricted portion 107b is formed in the upper portion near the opening of the battery case 107 and then the nickel piece 102a of the positive electrode 102 is connected thereto. Is disposed in the constricted portion 107b via a ring-shaped insulating packing 111. Thereafter, the upper edge of the battery case 107 is folded back and the outer peripheral edge of the encapsulating plate 108 is covered with the insulating packing 111, whereby the encapsulating plate 108 is electrically insulated from the battery case 107, and the battery case is sealed by the encapsulating plate 108. The
[0044]
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 stacked in this order. In the state of being laminated in this manner, the power generator 106 is manufactured by winding it in a roll shape so that the negative electrode 103 is on the outer side. Compared to the current collector made of a network skeleton made of nickel, it is relatively flexible, so the positive electrode 102 and the negative electrode 103 using this current collector are also relatively flexible, and it is compared with winding in a roll shape. The battery 101 itself can be easily assembled.
[0045]
In addition, the current collector made of nickel-plated hydrophilized non-woven fabric has high nickel plating adhesion, so the plating film quality will not change or be partially lost even after repeated battery assembly and charge / discharge. . For this reason, the battery using this current collector can improve the high-rate discharge characteristics and capacity compared to the conventional battery.
[0046]
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, 4 may be one in which the positive electrode 102 and the negative electrode 103 are wound in a spiral shape as shown in FIG.
[0047]
【Example】
Next, examples of the present invention will be described in detail together with comparative examples.
[0048]
Examples 1-4, Comparative Examples 1-4
A fiber web is formed by a conventional wet papermaking method using a slurry in which 100% by weight of a core-sheath type composite fiber having a fineness of 6.6 dtex and a fiber length of 5 mm, the core component of which is made of polypropylene and the sheath component of high-density polyethylene. did. The fiber web is heat-treated with a dryer set at 135 ° C., and the sheath component of the core-sheath type composite fiber is fused to have a basis weight of 100 g / m. ² A non-woven fabric with a thickness of 0.8 mm was made. The porosity of this nonwoven fabric was 86%.
[0049]
The nonwoven fabric was immersed in a fuming sulfuric acid solution at 80 ° C. to perform sulfonation treatment, and the obtained hydrophilic treatment nonwoven fabric was subjected to nickel plating treatment. In this nickel plating treatment, a hydrophilic treatment nonwoven fabric is wound around a carrier of a dyeing machine, a refining agent is circulated and washed with water, and then an aqueous solution containing 10 g / liter of stannous chloride and 20 ml / liter of hydrochloric acid is circulated and washed with water. Thereafter, an aqueous solution containing 1 g / liter of palladium chloride and 20 ml / liter of hydrochloric acid was circulated for catalysis.
[0050]
Thereafter, the plate is further washed with water, and electroless nickel plating solutions having various concentrations are added to nickel sulfate 18 g / liter, sodium citrate 109 / liter, hydrated hydrazine 50 ml / liter, and 25% aqueous ammonia 100 ml / liter. The nickel plating weight with respect to the total weight of the electric material was a liquid amount containing nickel in the amount shown in Table 1 below, and was heated to 80 ° C. and circulated. After circulating for 1 hour, the plating solution became almost transparent, the circulation was stopped, the nonwoven fabric was taken out, washed with water and dried to obtain a current collector.
[0051]
[Table 1]

In Table 1, the plating cross-sectional area is 20 μm ² ~ 130μm ² The current collectors of Example 1 to 4 are shown as Comparative Examples 1 to 4 and the current collectors of plating cross-sectional areas outside this range are shown as Comparative Examples 1 to 4. A battery test was performed on these current collectors. The measuring method is as follows.
[0052]
First, in Table 1, the packing density of active material (g / cm ^Three ) Is an active material, nickel hydroxide (Ni (OH)) ₂ ) Is collected, and the weight W (g) before filling the active material is subtracted from this weight to calculate the active material filling amount (W1-W). Next, the thickness T (cm) and area A (cm) of the current collector after being filled with the active material ² ). From these measurement results, the packing density of the active material was determined as the packing density (g / cm ^Three ) = (W1-W) / (A × T).
[0053]
In addition, the specific gravity of the nonwoven fabric (polypropylene / polyethylene) (g / cm ^Three ) Is 0.94 and the specific gravity of nickel metal (g / cm ^Three ) Was 8.9. From these values, the fiber specific gravity after plating (SG) (g / cm ^Three ) Was obtained from (current collector weight (g)) / {(nickel weight ÷ 8.9) + (nonwoven fabric weight ÷ 0.94)}.
[0054]
Next, in Table 1, the porosity (%) of the current collector is the thickness t (μm) of the current collector and the basis weight W (g / m). ² ), Porosity (%) = {1−W / (t × SG)} × 100. The utilization rate (%) was measured as follows. That is, an AA (AA) type battery (capacity 1200 mAh) was prepared using the current collectors of Examples and Comparative Examples for the positive electrode and nickel foam for the negative electrode, and the battery was charged and discharged at 20 ° C. and 0.1 C. Was activated. The test current was changed, and charging / discharging was performed every 5 cycles. The test current for each test rate 0.1C-3C was 0.1 × 1200 (mAh) for 0.1C, 1 × 1200 (mAh) for 1C, 2 × 1200 (mAh) for 2C, 3 × 1200 for 3C. (MAh). The utilization rate (%) was determined by the utilization rate (%) = {discharge capacity (average value of five measurements) ÷ 1200} × 100. The plating ratio (%) was determined by plating ratio (%) = {nickel weight (g) ÷ current collector weight W (g)} × 100.
[0055]
As is clear from Table 1, the plating cross-sectional area is 130 μm. ² If it exceeds 1, the fiber after plating becomes thick and the porosity decreases, so that the filling amount of the active material becomes insufficient. Also, the plating cross section is 20μm ² It was found that when the amount was less than 1, the plating amount was small and the surface resistance was high, so that a sufficient capacity could not be obtained by high-rate charge / discharge. In contrast, the plating cross-sectional area of the plated nonwoven fabric surface is 20 μm ² ~ 130μm ² In this range, it was found that the surface resistance of the plating film is low, the active material can be sufficiently filled, the battery can be increased in capacity, and a battery capable of high rate charge / discharge can be obtained.
[0056]
【Effect of the invention】
As described above, according to the invention of claim 1, the plating cross-sectional area of the plated nonwoven fiber surface is 20 μm. ² ~ 130μm ² Therefore, the surface resistance of the plating film is low, the active material can be sufficiently filled, the capacity of the battery can be increased, and a battery capable of high rate charge / discharge can be produced.
[0057]
According to the invention of claim 2, since the non-woven fabric is hydrophilized, the degree of adhesion of the non-woven fabric fibers to the plating film is increased and the surface resistance of the plating film is decreased, so that high-rate charge / discharge is possible. There is an effect.
[0058]
According to the invention of claim 3, since the non-woven fabric includes fibers having a fineness of 1.5 dtex or more, the porosity can be increased to increase the filling amount of the active material, and the plating amount can be adjusted. As a result, it is possible to easily obtain a predetermined plating cross-sectional area.
[0059]
According to the invention of claim 4, since the battery uses the current collector described in any one of claims 1 to 3, it is possible to obtain a battery having a high capacity and capable of high rate charge / discharge. Play.
[Brief description of the drawings]
FIG. 1 is a local enlarged view of a current collector of the present invention including a nonwoven fabric and a plating film.
FIG. 2 is a perspective view in which a part of the alkaline secondary battery of the present invention is cut away.
3 is a cross-sectional view taken along line AA of FIG. 2 in which a current collector is wound in a spiral shape.
4 is a cross-sectional view corresponding to FIG. 3 in which a current collector is wound into a spiral angle.
5 is a cross-sectional view corresponding to FIG. 3 in which the current collector is bent and stacked in a bellows shape.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Current collector, 11 ... Nonwoven fabric, 11a ... Contact point, 12 ... Plating film, 12a ... Electroless plating film, 12b ... Electrolytic plating film, 101 ... Alkaline secondary battery, 102 ... Positive electrode, 102a ... Nickel piece, 103 ... Negative electrode 104 ... Separator 104a ... First separator 104b ... Second separator 106 ... Power generator 107 ... Battery case 107a ... Can bottom, 108 ... Protrusion 109a ... Lower insulator 109b ... Upper insulator

Claims (4)

Non-woven fabric,
A battery current collector comprising a plating film formed on the surface of the nonwoven fabric,
A current collector for a battery, wherein a plating cross-sectional area of the surface of the plated nonwoven fabric on which the plating film is formed is 40 μm ² to 120 μm ² .   The current collector for a battery according to claim 1, wherein the nonwoven fabric is subjected to a hydrophilic treatment.   The battery current collector according to claim 1, wherein the non-woven fabric includes fibers having a fineness of 1.5 dtex or more.   A battery using the current collector according to claim 1.

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