JP4686810B2 - Lead acid battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lead-acid battery, particularly a lattice body.
[0002]
[Prior art]
In recent years, in order to improve the productivity of lead-acid battery grids, the expansion method that continuously expands lead or lead alloys into a thin sheet material by rolling or the like has been produced continuously by the casting method. Widely used because it can.
[0003]
In this expanding method, the die blade is reciprocated to form a plurality of intermittent parallel slits on the sheet in a staggered manner, and the line portions surrounded by the adjacent slits are expanded and elongated in the sheet thickness direction to form a mesh. The reciprocating expanding method for forming the part and the rotary expanding method as described in JP-A-3-204126 are roughly divided.
[0004]
In the reciprocating expansion method, it is difficult to increase the speed of reciprocating motion due to the inertia of the die blade because it is necessary to reciprocate the heavy die blade. On the other hand, unlike the reciprocating expand method, the rotary expand method described above forms slits with a rotating processing blade, so there is less need to consider the inertia of the processing blade, and the rotational speed of the processing blade is increased compared to the reciprocating expand method. This has the advantage that the production speed can be easily improved.
[0005]
Although the rotary expand method is excellent in productivity as described above, for example, according to the method described in Japanese Patent Laid-Open No. 3-204126, the lattice bone is once stretched up and down from the sheet surface in the process of forming. After being stretched, the sheet is stretched in two different directions in order to be stretched in the sheet width direction. In such a case, the lattice bone is subjected to twisting. Such twisting significantly reduces the strength of the grid and the oxidation resistance when used for the positive electrode.
[0006]
In particular, in recent lead-acid batteries, the lead alloy sheet needs to be thinned for the purpose of reducing the weight, and the above-mentioned strength of the lattice body and the degree of reduction in oxidation resistance have a great influence on the life reduction, further increasing the life of the battery. There was a problem of significant reduction.
[0007]
[Problems to be solved by the invention]
An object of the present invention is to improve battery life in a lead storage battery including a lattice body by the rotary expanding method as described above.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention forms a plurality of parallel slits intermittently along the longitudinal direction of the lead alloy sheet, and is adjacent to each other in parallel at intervals. A lead-acid battery comprising a positive electrode lattice body having a mesh part formed by extending and extending the lead alloy sheet in the width direction while causing the linear part formed by the slit to protrude vertically from the surface of the lead alloy sheet , The dimension in the slit formation direction of the knot portion of the mesh portion is A, the projection length in the slit formation direction of the line portion of the mesh portion is B , and the projection length of the knot portion in the width direction of the lead alloy sheet When A is C , the ratio A / B is 0.2 ≦ A / B ≦ 0.7 , and the ratio A / C is 1.5 ≦ A / C ≦ 4.5 .
[0009]
The invention according to claim 2 is such that the ratio A / B is 0.3 ≦ A / B ≦ 0.55.
[0011]
In the invention according to claim 3 , the lead alloy sheet has a thickness of 0.4 mm to 1.2 mm.
[0012]
In the invention according to claim 4 , the lead alloy sheet is a lead-calcium-tin alloy having a calcium content of 0.04 to 0.09% by mass and a tin content of 0.1 to 2.0% by mass. The strength is 78 N / mm ² or less.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1 and FIG. 2, the rolled lead alloy sheet 1 passes between a pair of cutter rolls 2-2 in which disk cutters 2 each having a processing blade 2-1 formed on the circumference are laminated in the thickness direction. An intermittent slit is formed, and the linear portion 3 surrounded by the intermittent slit is protruded from the surface of the rolled alloy sheet 1 in a convex or arc shape in the vertical direction, and every other nodule portion 4 is cut to form a non-nodule portion. 5 is formed. At this time, the non-nodule portions 5 and the nodule portions 4 are alternately formed.
[0014]
The disk-shaped cutter 2 is laminated as shown in FIG. 1 to form a cutter roll 2-2. On the circumference of the disk-shaped cutter 2, a processing blade 2-1 and a flat portion 2-3 are formed. The processing blade 2-1 forms an intermittent slit in the rolled lead alloy sheet 1 and causes the linear portion 3 to protrude in a convex or arc shape in the vertical direction with respect to the surface of the rolled lead alloy sheet 1. Further, a relief portion 2-4 is formed corresponding to the flat portion 2-3 as shown in FIG. The escape portions 2-4 are formed as thin portions alternately in the thickness direction of the disk-shaped cutter 2. Since the escape portions 2-4 are alternately formed in the thickness direction of the disc-like cutter 2, when the disc-like cutter 2 is paired as shown in FIG. 1, the portions where the escape portions 2-4 face each other A non-facing part is formed. In the portion where the escape portions 2-4 face each other, a space is formed between the escape portions 2-4, and the lead rolled sheet 1 corresponding to this portion is not cut, and as a result, the knot portion 4 is formed. In the portion where the escape portions 2-4 do not face each other, the lead rolled sheet 1 is cut by the flat portion 2-3 to form the non-nodal portion 5.
[0015]
Next, the expanded lead mesh sheet 6 shown in FIG. 4 is formed by extending the lead rolled sheet 1 in the width direction (W direction in FIGS. 2 and 4).
[0016]
FIG. 5 is an explanatory diagram showing the correspondence between the expanded mesh portion 6 and the disc-like cutter 2.
[0017]
The lattice body used for the lead storage battery of the present invention includes an expanded mesh portion 6 as a lattice as shown in FIG. Here, in the present invention, the length dimension of the knot part 4 in the slit forming direction is A, the projected length of the linear part 3 in the slit forming direction is B, and the projected length of the knot part 4 in the lead rolled sheet width direction is C. 0.2 ≦ a / B ≦ 0.7 is and 1.5 ≦ a / C ≦ 4.5 when, in which preferably a 0.3 ≦ a / B ≦ 0.5 5 . In order to obtain the expanded mesh portion 6 having such a dimension relationship, as shown in FIG. 5, the circumferential length of the flat portion 2-3 having the dimension a and the circumferential length of the machining blade 2-1 having the size b and the clearance portion 2-4 are obtained. Since twice the thickness dimension c ′ corresponds to the A dimension, the B dimension, and the C dimension, respectively, the expanded mesh portion for the grid body used in the lead storage battery of the present invention is obtained by using the disk-shaped cutter 2 that satisfies the dimensional relationship described above. Can be configured.
[0018]
By setting it as such a structure, the twist of the filament part 3 can be suppressed to the minimum. In the configuration in the numerical range other than the present invention, the twist of the wire portion 3 and the knot portion 4 is large, and the cross-sectional area of the wire portion 3 is 3/4 or less, which is not preferable because it is distorted and the electric resistance increases.
[0019]
After that, the expanded mesh portion 6 obtained here is filled with an active material paste according to a conventional method, and then cut into a single electrode plate, and after aging and drying, becomes an unformed electrode plate. Using this electrode plate as a positive electrode plate, the conventional separator and negative electrode plate can be combined to obtain the lead storage battery of the present invention by a conventional assembling method and chemical charging method.
[0020]
Here, by using a rolled lead alloy sheet 1 having a tensile strength of 78 N / mm ² or less, it is possible to prevent minute cracks that are generated when the filament 3 is twisted.
[0021]
The rolled lead alloy sheet having such tensile strength is a lead-calcium-tin alloy having a calcium content of 0.04 mass% to 0.09 mass% and a tin content of 0.1 mass% to 2.0 mass%. And the thickness is preferably at least 1.2 mm. Moreover, regarding this thickness, in order to suppress the deformation | transformation of the filament part 3 in a subsequent paste filling process, it is necessary to set it as 0.4 mm or more.
[0022]
【Example】
According to the embodiment of the invention described above, an expanded grid for a positive electrode was produced, and a lead storage battery for automobiles according to the present invention example of 12V55Ah was produced using this grid. However, regarding the expanded lattice body, a comparative example expanded lattice body having a dimensional relationship according to the embodiment of the invention and a comparative example having dimensions other than this dimensional relationship is produced, and this lattice body is used as a positive electrode lattice body for comparison of 12V55Ah. An automotive lead-acid battery by example was prepared.
[0023]
The rolled lead alloy sheet used had a composition of Pb-0.06 mass% Ca-1.4 mass% Sn and a thickness of 0.8 mm. Further, in order to make the mesh pitch of the lattices the same, the ratios A / B and A / C were changed while keeping A + B = 2.34 mm constant.
[0024]
A life test was conducted on the lead storage batteries according to the present invention examples and comparative examples. As the life test, a light load life test defined in JIS-D5301 was performed in a gas phase atmosphere at 75 ° C. The result is shown in FIG.
[0025]
From the results shown in FIG. 6, it can be seen that the life cycle number can be increased by setting the ratio A / B to be not less than 0.2 and not more than 0.7. It can also be seen that if the ratio A / B is 0.3 or more and 0.55 or less, the number of life cycles can be stably increased. Moreover, such an arrangement it can be seen that to obtain effect if 4.5 or less A / C is 1.5 or more.
[0026]
The batteries after the end of the life test were disassembled and examined, and in particular, the state of the positive electrode grid was observed. As a result, when A / B <0.2, the nodule portion was severely corroded, and the line portion and the line portion were cut at the position of the nodule portion. When A / B> 0.7, the corrosion at the striated portion proceeded more significantly than at the nodule portion, and was cut in the middle of the striated portion. In particular, when A / B is 0.3 or more and 0.55 or less, the corrosion progresses, but the corrosion of the wire portion and the nodule is relatively small and progresses evenly. It is thought that the lifetime could be increased.
[0027]
In this way, by particularly limiting the ratio A / B to a certain numerical range, it is possible to suppress corrosion occurring at the line portion and the nodule portion and to promote the corrosion of both in a balanced manner, and a part of the lattice network is corroded and cut. It is possible to suppress a sudden decrease in life due to the above.
[0028]
The effect can also be obtained by using a rolled lead alloy sheet in which a surface layer of a lead-antimony alloy or a lead-tin alloy is formed on the surface of the lead sheet by pressure bonding or coating.
[0029]
【The invention's effect】
As described above, according to the configuration of the present invention, the life of the positive electrode grid body, which has been conventionally generated in the lead storage battery using the rotary expanded grid body, is suppressed, and the productivity of the lead storage battery having excellent life characteristics is impaired. Therefore, the present invention is extremely useful industrially.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a disk-shaped cutter roll. FIG. 2 is an explanatory view of a main part showing a lattice body used in the lead storage battery of the present invention. FIG. 3 is an explanatory view showing a manufacturing process of the lattice body used in the lead storage battery of the present invention. FIG. 4 is a plan view showing an expanded mesh part. FIG. 5 is an explanatory diagram showing a relationship between the expanded mesh part and a machining blade. FIG. 6 is a diagram showing life characteristics of lead storage batteries of the present invention and a comparative example. Explanation of]
DESCRIPTION OF SYMBOLS 1 Rolled lead alloy sheet 2 Disc shaped cutter 2-1 Processing blade 2-2 Cutter roll 2-3 Flat part 2-4 Escape part 3 Line part 4 Knot part 5 Non-knot part 6 Expanded mesh part

Claims (4)

A plurality of slits parallel to each other are intermittently formed along the longitudinal direction of the lead alloy sheet, and the linear portions formed by the slits adjacent to each other in parallel are projected vertically from the surface of the lead alloy sheet. , Comprising a positive grid having a mesh part formed by extending and extending the lead alloy sheet in the width direction, the dimension of the slit forming direction of the knot part of the mesh part is A, and the line part of the mesh part The ratio A / B is 0.2 ≦ A / B ≦ 0.7 , the ratio A / when the projected length in the slit forming direction is B and the projected length in the width direction of the lead alloy sheet of the nodule portion is C. A lead-acid battery, wherein C is set to 1.5 ≦ A / C ≦ 4.5 .   2. The lead acid battery according to claim 1, wherein the ratio A / B is set to 0.3 ≦ A / B ≦ 0.55. Lead-acid battery according to any one of claims 1 to 2, wherein the thickness of the lead alloy sheet is 0.4Mm～1.2Mm. The lead alloy sheet is a lead-calcium-tin alloy having a calcium content of 0.04 to 0.09 mass% and a tin content of 0.1 to 2.0 mass%, and has a tensile strength of 78 N / mm ² or less. The lead acid battery according to any one of claims 1 to 3 .

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