JP2004146179A - Lead acid storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long lifetime lead acid storage battery to suppress disconnection of a knot part of a grille shape object and reduction of the lead acid storage battery capacity thereby caused, which occur in the lead acid storage battery using an expanded meshes of a net as the grille shape object by a rotary expanding method superior in productivity. <P>SOLUTION: A plurality of strips of intermittent slits are formed in parallel in a sheet constituted of lead or lead alloy, and threads parts formed between the slits are made to protrude in the vertical direction against the sheet face, and in the lead acid battery provided with the expanded grille shape object formed by developing and extending this sheet in the width direction, and in the knot part and the threads part of the meshes of the net constituting the expanded grille shape object, the tensile strength in the width direction of the sheet of the knot part is made to be the tensile strength or more in the longitudinal direction of the threads part. <P>COPYRIGHT: (C)2004,JPO

Description

【００２８】
表１に示した各電池についてＪＩＳ−Ｄ５３０１に規定された軽負荷寿命試験を放電時間を４分から１分に変更し７５℃気相雰囲気下で行った。その結果を表１に示した。表１に示した結果、従来例による電池１、４、７および１０は本発明例による電池に比較して短寿命であった。これらの従来例の電池を分解調査を行ったところ、正極格子の結節部での断線が発生していた。特にこの現象は電槽内壁と直接接触する正極板の存在する電池４、１０において顕著であった。
【００２９】
一方、電槽内壁に直接接触する構成であっても本発明の構成による電池５、６、１１および１２は極めて優れた寿命特性を有していた。
【００３０】
【発明の効果】
以上、説明してきたように、本発明の構成によれば、生産性に優れたロータリーエキスパンド格子体を用いた鉛蓄電池の特に正極格子の結節部において従来顕著に発生していた断線を抑制し、これによる容量低下を抑制するとともに、長寿命の鉛蓄電池を生産性よく安価に提供できることから、工業上、極めて有用である。
【図面の簡単な説明】
【図１】円盤状カッターを示す図
【図２】カッターロール対を示す図
【図３】凸状加工刃によってシート上に形成されたスリットを示す図
【図４】凸状加工刃を示す図
【図５】カッターロール対の断面を示す図
【図６】シート上に形成されたスリットを示す図
【図７】千鳥状スリットを形成したシートの断面を示す図
【図８】エキスパンド網目を示す図
【図９】本発明の鉛蓄電池の格子体を示す図
【図１０】本発明の鉛蓄電池の格子体の製造工程を示す図
【符号の説明】
１　　　　凸状加工刃
２　　　　円盤状カッター
３、３´　　　カッターロール
４　　　　　　シート
５　　　　　　スリット
６　　　　　　断続部
７　　　　　　平坦部
８　　　　　　薄肉部
９　　　　　　逃げ部
１０　　　　　反対面
１１　　　　　千鳥状スリット
１２　　　　　線条部
１３　　　　　エキスパンド網目
１４　　　　　結節部
１５　　　　　格子体
１６　　　　　結節部
１７　　　　　線条部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a lead storage battery used for an automobile or the like.
[0002]
[Prior art]
BACKGROUND ART In recent years, a grid body of a lead storage battery has been used from a casting method to an expanding method for the purpose of improving productivity. In the expanding method, generally, a slit is formed in a lead-calcium alloy sheet, and the slit is developed to form a mesh.
[0003]
Among the expanding methods, the reciprocating method has been generally used. In this reciprocating expansion method, a slit is formed in the lead alloy sheet by intermittently feeding the lead alloy sheet into a reciprocating mold, and the strand that is sandwiched between the slits at the tip of the mold becomes a sheet. In the width direction to form a mesh.
[0004]
For this reason, in order to improve the production speed of the mesh, it is necessary to increase the number of blades of the mold or to increase the press speed. However, in such a method, there is a problem that the weight of the mold is increased, a press machine with a larger output is required, and the equipment becomes larger and the running cost is increased. Therefore, as a means for further improving the productivity, a rotary expanding method as described in Patent Document 1 is being adopted. In this method, a sheet is passed between a pair of cutter rolls 3 and 3 'in which a disc-shaped cutter 2 having a convex processing blade 1 as shown in FIG. 1 is formed at intervals as shown in FIG. To form a staggered slit in the sheet. According to this method, the production speed can be relatively easily increased by increasing the rotation speed of the cutter roll.
[0005]
The pair of cutter rolls 3 and 3 ′ are arranged such that the convex processing blades 1 face each other, and the sheet 4 is sheared by the overlapping of the convex processing blades 1, and the intermittent slit 5 as shown in FIG. A plurality of strips are formed in parallel according to the number of disk-shaped cutters 2. Flat portions 7 are formed between the convex processing blades 1, and the flat portions 7 correspond to the intermittent portions 6. In order to develop the expanded mesh by expanding the slits 5, it is necessary to alternately cut the intermittent portions 6 between the slits 5 so that the slits 5 are staggered.
[0006]
In the rotary expanding method described in Patent Document 1, in order to cut the intermittent portion 6 alternately, as shown in FIG. 4, a thin portion 8 is alternately provided in a thickness direction on a flat portion 7 between the convex processing blades 1. Then, in the cutter roll pairs 3 and 3 'shown in FIG. 2, the flat portions 7 are arranged so as to overlap each other. FIG. 5 is a cross-sectional view showing a state in which the cutter roll pairs 3 and 3 ′ are arranged so as to overlap with each other. A portion where the thin portions 8 face each other forms a relief portion 9, and an intermittent portion corresponding to the relief portion 9. 8 is not cut. On the other hand, a portion where the opposite surfaces 10 of the thin portion 8 overlap each other forms a shear portion, and the intermittent portion 6 corresponding to the shear portion is cut. In this way, the intermittent portions 6 are alternately cut to form a staggered slit in the sheet.
[0007]
In this way, the staggered slits 11 are formed on the sheet 4 as shown in FIG. When the AA ′ cross section of the sheet 4 is viewed, as shown in FIG. 7, the linear portion 12 surrounded by the staggered slits 11 has an arc shape in the vertical direction according to the tip shape of the convex processing blade 1. It protrudes.
[0008]
Thereafter, the expanded mesh 13 as shown in FIG. 8 is formed by expanding the sheet 4 in the width direction. This expanded mesh is composed of the striated portions 12 and the knots 13 connecting the striated portions 12 to each other. The node 13 corresponds to the intermittent portion 6 remaining without being cut.
[0009]
In such a rotary expanding system, an expanded network can be formed at a relatively high speed. However, as shown in FIG. 5, the knot portion 14 is deformed when the intermittent portion 6 is sheared, and the stress is concentrated. Further, as shown in FIG. 7, since the linear portions 12 protrude in an arc shape in the vertical direction of the surface of the sheet 4 and then are developed in the sheet width direction, the linear portions 12 are twisted. This twist causes stress to be applied to the striated portion 12 itself, but the stress also concentrates on the knot portion 14 which is a fulcrum of the striated portion 12.
[0010]
When such an expanded mesh is used as a grid of a lead-acid battery, the nodal portion 14 where the stress during the expanding process is concentrated is corroded, or is broken by the tensile force due to the expansion of the positive electrode active material, and the life is shortened relatively early. There was a problem of reaching.
[0011]
Such a phenomenon that the node 14 of the grid is corroded is caused by the number of the negative electrode plates in the electrode plate group constituting the unit cell in the automotive lead-acid battery or the battery which is frequently used particularly in a high temperature environment. Is remarkable in a storage battery having the same number of positive electrode plates or one less than the number of positive electrode plates. In the case of such an electrode plate group configuration, one or both of the two electrode plates (hereinafter, referred to as end plates) located at both ends of the electrode plate group are positive electrode plates.
[0012]
Such an end plate is a positive electrode plate, and the configuration in which the positive electrode end plate is in direct contact with the inner wall of the battery case, that is, the negative electrode plate is stored in a bag-shaped separator, or is not a bag-shaped separator, but a leaf-shaped separator It has been found that, in the case of using a positive electrode plate, the probability that the volume of the positive electrode end plate expands due to corrosion and the nodal portion breaks to lower the battery capacity is larger than that of the other positive electrode plates that are not end plates.
[0013]
In the case of the positive electrode plate sandwiched between the negative electrode plates, both sides of the positive electrode plate are relatively uniformly pressed by the compression force in the thickness direction of the positive electrode plate due to expansion of the positive electrode active material and the negative electrode active material. When the end plate is a positive electrode plate, it is presumed that since both surfaces of the electrode plate are not evenly sandwiched, disconnection of the nodal portion occurs and the battery capacity tends to decrease.
[0014]
[Patent Document 1]
JP-A-3-204126
[Problems to be solved by the invention]
The present invention suppresses disconnection of the grid body and a decrease in battery capacity due to disconnection of the grid body generated in the lead storage battery using the expanded mesh by the rotary expand system having excellent productivity as described above, and has a long life. It is intended to provide a lead storage battery.
[0016]
[Means for Solving the Problems]
In order to solve the above-described problems, a plurality of intermittent slits are formed in a sheet made of lead or a lead alloy according to the present invention in parallel, and the linear portions formed between the slits are vertically moved with respect to the sheet surface. A lead-acid battery provided with an expanded lattice body formed by projecting the sheet in the direction and expanding and expanding the sheet in the width direction, and in a knot portion and a striated portion of the mesh forming the expand lattice body, the sheet width direction of the knot portion Is a lead storage battery characterized in that the tensile strength of the lead-acid battery is equal to or higher than the tensile strength in the length direction of the striated portion.
[0017]
The invention according to claim 2 of the present invention is directed to a lead-acid battery according to claim 1, wherein the number of negative electrodes is equal to or less than the number of positive electrodes.
[0018]
Further, the invention according to claim 3 of the present invention relates to the lead storage battery according to claim 1 or 2, further comprising a positive electrode plate which is in direct contact with the inner wall of the battery case.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
The configuration of the lead storage battery according to the embodiment of the present invention will be described.
[0020]
The grid body used in the lead storage battery according to the present invention is formed by a rotary expanding method, and thus has a twist in the linear portion as shown in FIG. Although various methods have been described as a method for producing a lattice body by the rotary expanding method, the lattice body can be produced by a method as shown in Patent Document 1 exemplified in the related art. The expanded mesh by the rotary expanding method has a plurality of slits intermittently formed in a sheet serving as a lattice material in parallel, and the slit intermittent portions are alternately cut, and the linear portions located between the slits are formed into an arc shape in the vertical direction. After being protruded, an expanded mesh obtained by expanding the sheet in the width direction, that is, a direction substantially orthogonal to the slit is used as at least the positive electrode grid.
[0021]
In the present invention, as shown in FIG. 9, the tensile strength in the sheet width direction (W direction in FIG. 9) of the knot portion 16 constituting the lattice body 15 is Tn, and the length direction of the striated portion of the striated portion 17 ( Ts ≦ Tn, where Ts is the tensile strength in the direction (L direction in FIG. 9). Various methods can be adopted to obtain such a configuration. For example, this can be achieved by increasing the length of the intermittent portion 6 shown in FIG. As another method, the volume of the escape portion 9 is increased by making the thin portion 8 thinner, and the stress applied to the knot portion 16 is reduced. As still another method, in the overlapping of the cutter roll pair shown in FIG. 5, the overlapping amount (C dimension in FIG. 5) of the flat portions 7 is set to 0 or the flat portions 7 facing each other as shown in FIG. By separating only a minimal amount of about 0.1 to 0.3 mm, the deformation of the node 16 can be suppressed to a minimum. In particular, when the flat portions 17 are separated from each other, the intermittent portion 6 is not completely cut, but is easily cut by the spreading process in the sheet width direction, and the sheet is spread.
[0022]
The lead storage battery of the present invention can be obtained by using the grid body 15 thus obtained at least as a positive grid body, and thereafter configuring the lead storage battery by a conventional method. As the sheet material, conventionally used calcium necessary to secure a sheet strength of about 0.03 to 0.10% by mass and a favorable effect on sheet corrosion resistance of about 0.20 to 2.00% by mass are required. A rolled sheet which is a Pb-Ca-Sn alloy containing tin enough to secure the rolling structure and has a rolled structure suitable for expanding by rolling can be used.
[0023]
In the lead storage battery of the present invention obtained in this way, the disconnection of the nodal portion 16 which has conventionally occurred remarkably in the rotary expanded grid can be suppressed, and a lead storage battery having stable life characteristics can be obtained.
[0024]
Such a configuration of the present invention is preferably applied to a lead storage battery in which the number of negative electrodes constituting the electrode group is equal to or less than the number of positive electrodes. In a lead-acid battery having such an electrode configuration, one or both of the end plates serve as positive plates, and both surfaces of the positive plate serving as an end plate are not pressed by the negative plates. As a result, the volume expansion due to corrosion of the positive electrode plate becomes an end plate and becomes significantly larger than that of the positive electrode plate, and the nodes of the lattice body are easily disconnected, and the frequency of the battery capacity is extremely rapidly reduced. By applying the configuration of the present invention to a lead storage battery having a simple electrode plate configuration, the effects of the present invention can be more remarkably obtained.
[0025]
In addition, in the case where one of the end plates of the electrode plate group is a positive electrode plate, particularly in a lead-acid battery in which the positive electrode plate is in direct contact with the inner wall of the battery case, the inner wall of the battery case is smooth. The disconnection of the knot is further promoted by further increasing the volume expansion of the extreme plate. Therefore, it is preferable to apply the configuration of the present invention to a lead storage battery in which the positive electrode plate is in direct contact with the inner wall of the battery case. Such a configuration corresponds to a configuration in which only the negative electrode plate is housed in a bag-shaped separator, or a configuration in which a leaf-shaped separator is used instead of a bag-shaped separator.
[0026]
【Example】
Rolled sheet having a total thickness of 1.0 mm, made of a Pb-0.07% by mass Ca-1.60% by mass Sn alloy, and having a Pb-7% by mass Sb-5% by mass Sn alloy layer formed on its surface with a thickness of 10 μm. Was prepared, and a positive electrode grid body was prepared by the rotary expanding method described in the embodiment of the invention. Note that, by changing the amount of superposition of the flat portion 7 of the disc-shaped cutter used for the expanding process, the knot portion 16 constituting the lattice body 15 shown in FIG. 9 in the sheet width direction (W direction in FIG. 9). The tensile strength was Tn, and the tensile strength in the length direction of the striated portion 17 (L direction in FIG. 9) was prepared by changing Ts variously. Using these positive electrode grids, a 55D23 type lead-acid battery defined by JIS-D5301 was created with the configuration shown in Table 1. As the separator, a bag-shaped separator made of microporous polyethylene was used, and either the positive electrode plate or the negative electrode plate was housed in the bag-shaped separator.
[0027]
[Table 1]

[0028]
For each battery shown in Table 1, a light load life test specified in JIS-D5301 was performed in a gas phase atmosphere at 75 ° C. with the discharge time changed from 4 minutes to 1 minute. The results are shown in Table 1. As shown in Table 1, the batteries 1, 4, 7, and 10 according to the conventional example had a shorter life than the battery according to the example of the present invention. When these conventional batteries were disassembled and examined, disconnection occurred at the nodal portion of the positive electrode grid. In particular, this phenomenon was remarkable in the batteries 4 and 10 in which the positive electrode plate was in direct contact with the inner wall of the container.
[0029]
On the other hand, the batteries 5, 6, 11 and 12 according to the configuration of the present invention had extremely excellent life characteristics even when they were configured to directly contact the inner wall of the battery case.
[0030]
【The invention's effect】
As described above, according to the configuration of the present invention, a lead storage battery using a rotary expanded grid body having excellent productivity suppresses a disconnection that has been conventionally remarkably generated particularly at a node of a positive grid, This is extremely useful industrially because it can suppress a decrease in capacity due to this and can provide a long-life lead-acid battery with good productivity at low cost.
[Brief description of the drawings]
FIG. 1 shows a disk-shaped cutter. FIG. 2 shows a pair of cutter rolls. FIG. 3 shows a slit formed on a sheet by a convex processing blade. FIG. 4 shows a convex processing blade. FIG. 5 is a view showing a cross section of a pair of cutter rolls. FIG. 6 is a view showing a slit formed on a sheet. FIG. 7 is a view showing a cross section of a sheet having a staggered slit. FIG. 8 is a view showing an expanded mesh. FIG. 9 is a view showing a grid of a lead storage battery of the present invention. FIG. 10 is a view showing a manufacturing process of a grid of a lead storage battery of the present invention.
DESCRIPTION OF SYMBOLS 1 Convex processing blade 2 Disc-shaped cutter 3, 3 ′ Cutter roll 4 Sheet 5 Slit 6 Intermittent part 7 Flat part 8 Thin part 9 Escape part 10 Opposite surface 11 Staggered slit 12 Line part 13 Expanded mesh 14 Knot part 15 Grid Body 16 Knot 17 Striated

Claims (3)

A plurality of slits intermittently formed in a sheet made of lead or a lead alloy are formed in parallel with each other, and the linear portions formed between the slits are projected vertically with respect to the sheet surface, and the sheet is made to extend in the width direction. A lead-acid battery provided with an expanded lattice formed by expanding and expanding, wherein at a knot portion and a striated portion of a mesh forming the expanded lattice member, the tensile strength of the knot portion in the sheet width direction is set to the linear value. A lead-acid battery characterized by having a tensile strength in the longitudinal direction of the portion or more. 2. The lead-acid battery according to claim 1, wherein the number of the negative plates is equal to or less than the number of the positive plates. The lead-acid battery according to claim 1, further comprising a positive electrode plate that directly contacts an inner wall of the battery case.

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