JPH0513084A - Manufacture of lead sheet for lead-acid battery grid - Google Patents

Abstract

PURPOSE:To provide a highly reliable method for manufacturing a lead sheet, ensuring a high bonding force at the process where the continuous cast body of lead alloy (slab) and various types of alloy foils (allay ribbons) are rolled and compacted to each other. CONSTITUTION:At the manufacture process of an expanded grid sheet where an arbitrary lead alloy foil is superposed on the continuous cast body of lead allay (slab), and rolled and compacted in many steps to form an arbitrary alloy layer on a sheet surface, a temperature difference between the slab and lead alloy ribbon is kept within 150 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a lead sheet for a grid of a lead storage battery.

[0002]

2. Description of the Related Art Recently, a continuous cast body of a thick lead alloy (hereinafter referred to as a slab) is rolled as a grid for a lead storage battery by a multi-stage roller to form a sheet, which is reticulated by a mechanical reticulation method generally called expand. As a body, many methods of using this for the lattice have been adopted.

In particular, in response to the recent demand for maintenance-free operation, this method has been positively adopted for lead-calcium alloys. At this time, as an alloy different from the slab at the stage of manufacturing a sheet as a means of compensating for its drawbacks while making use of the advantages of various alloys, for example, a tin-based alloy is used for recoverability after over-discharge, durability and high durability in deep discharge. For durability against temperature, a technique is disclosed in which a thin ribbon of an antimony alloy (hereinafter referred to as an alloy ribbon) is superposed on a slab and a different alloy layer is provided on the surface of the sheet and, consequently, a part of the surface of the lattice. It was

However, the electronics of vehicles has become more and more active, and due to the influence of overcrowding in the engine compartment, the reliability of repeated deep discharge and high temperature has been further required.

Along with this tendency, the addition ratio of calcium in the calcium alloy of the base material is increased to increase the tensile strength, and the addition ratio of tin and antimony on the surface also tends to be increased.

Along with this, a kind of short-life phenomenon that has hitherto not been noticed is occurring. Upon detailed investigation of this cause, it was discovered that there was a problem in the manufacturing stage of the lead sheet.

That is, there is a variation in the bonding state of the alloy ribbon which should have been rolled and integrated, and peeling may occur during the expanding process or during use of the electrode plate, causing a problem in the adhesion between the active material and the lattice. It turned out to be a result.

[0008]

That is, a slab is a reliable condition that various kinds of alloys can be surely adapted at the stage of rolling and crimping an alloy ribbon of a dissimilar alloy together with the slab to obtain an excellent joining force. Finding out became an important issue.

[0009]

According to the present invention, in order to solve the above-mentioned problems, in the step of superposing an alloy ribbon on a slab and press-rolling, the temperature difference between the slab and the alloy ribbon is rolled at 150 ° C or less. Disclosed is a method of manufacturing a lead sheet for a grid of a lead storage battery, the method including steps.

[0010]

By limiting the temperature difference between the slab and the alloy ribbon as described above, the bondability between the ribbon and the slab on the surface of the sheet after pressure-bonding rolling is significantly improved. The exact principle of this effect has not been clarified, but seems to be closely related to the ductility of the lead alloy. Lead alloys, regardless of whether they are antimony-based, tin-based, or calcium-based, show a relatively small extensibility from around room temperature to around 70 ° C., and they tend to slightly increase as the temperature rises. If the temperature is exceeded, the creep phenomenon will rapidly increase, the ductility will become much larger than in the region described above, and the difference in absolute value will increase depending on the type and composition of the alloy.

Therefore, for example, when the surface temperature of a freshly cast slab is high, the smaller the temperature difference from the ribbon, the better the bondability. Further, when applying a ribbon having a temperature close to the normal temperature range, the bondability is improved by lowering the temperature of the slab and limiting the temperature difference with the ribbon. The maximum temperature difference is 1 considering productivity.
It must be within 50 ° C.

Other factors such as the rolling rate and the pressure are arbitrary on an industrial level. In this way, by limiting the temperature difference and making the malleability close to each other, slippage of the joint surface can be prevented and the peeling phenomenon can be suppressed. In order to exert this effect, the first rolling stage in multi-stage rolling is the most important. If the slab and ribbon are joined well at this stage, the desired quality can be easily obtained without the meandering of the surface foil layer. For that purpose, the ribbon should be in contact with the slab that is not cast for as long as possible or run side by side to eliminate the difference between the ribbon temperature and the slab temperature, or cool the slab to reduce the temperature difference.
It is better to enter the first rolling stage. For the cooling of the slab, we tried methods such as heat exchange and direct application of cooling oil, but the former has a large-scale device and the latter has a risk of impurities remaining between the slab and the ribbon. In this respect, the method of simply cooling with water is advantageous because it has a large cooling effect by evaporation heat and does not leave a residue.

Although the effects of the present invention as described above are recognized in a wide range of alloy system combinations, the calcium addition amount of 0.1% by weight or more for slabs of calcium-based alloys and the tin addition amount of ribbons are 0. An amount of 0.5% by weight or more and an antimony of 1% by weight or more show a remarkable effect in the low temperature region where the spreadability is remarkably reduced.

[0014]

EXAMPLES The features and effects of the present invention will be described below with reference to examples. FIG. 1 is an example of a lead alloy sheet manufacturing apparatus for carrying out the present invention. Slab 1 cast from casting machine 3
Is temperature-controlled by cooling water 5 and ribbons 4, 4 '
Are infrared heaters 7 and 7'and cooling water jets 8 and 8 '
The temperature is set to the desired temperature. Reference numerals 9 and 9'indicate drainage ports. The temperature-controlled slab 1 and ribbons 4 and 4'are simultaneously rolled by a rolling mill 2 to produce a lead sheet 10 having a constant thickness.

Using the above apparatus, the amount of calcium added to the slab is 0.02% to 0.3% by weight, the amount of tin added to the ribbon is 0.5% to 10% by weight, and the amount of antimony added. The lead sheet was manufactured by changing the addition amount from 1% by weight to 10% by weight. In the first rolling stage, the temperature of the slab was 20 ° C to 220 ° C, and the temperature difference between the slab and the ribbon was 0 ° C to a maximum of 200 ° C.

The lead sheet evaluation method is normal if the trial-produced lead sheet is cut by 1 m to make 100 samples, and the ribbon on the surface of the sample does not peel off and the ribbon does not peel off even if the sample is folded. Then, the defect rate was investigated.

FIG. 2 is a diagram showing the defective rate of the sheet due to the temperature difference between the slab and the ribbon. The vertical axis shows the defect rate, and the horizontal axis shows the temperature difference between the slab and the ribbon. As a typical example, the amount of calcium added to the slab was 0.15% by weight, the amount of tin added to the ribbon was 5.0% by weight, and the amount of antimony added to the ribbon was 5.0% by weight. The temperature of each slab is A2
0 ℃, B80 ℃, C120 ℃, D150 ℃, E190
℃ and F220 ℃. As is clear from FIG. 2, when the temperature difference between the slab and the ribbon is 150 ° C. or lower and the surface temperature of the slab is 20 ° C. or higher and 190 ° C. or lower, a lead sheet which is expected to have a low defect rate can be obtained.

However, considering productivity such as temperature control of the slab and ribbon, the slab temperature is 20 ° C. or higher and 120
It is more desirable that the temperature difference is 100 ° C. or less and the temperature difference is 100 ° C. or less.

FIG. 3 shows the percent defective of the sheet for each temperature difference with respect to the amount of calcium contained in the slab, and FIGS. 4 and 5 show the percent defective of the sheet for each temperature difference with respect to the amount of tin and antimony contained in the ribbon. This is a typical example. In each figure, the vertical axis shows the defect rate and the horizontal axis shows the temperature difference between the slab and the ribbon. G, H and I contain 0.05% by weight, 0.15% by weight and 0.25% by weight of calcium contained in the slab, and J, K and L show 3% by weight of tin contained in the ribbon. The amount of antimony contained in the ribbon is 5% by weight, 7% by weight, and the amount of antimony contained in the ribbon is 3% by weight, 5% by weight, and 7% by weight. The temperature of all the slabs was 80 ° C. From these results, the amount of calcium added to the slab was 0.1% by weight.
As described above, in the ribbon, the tin addition amount is 0.5% by weight or more,
For antimony, 1% by weight or more restricts the temperature difference between the slab and the ribbon even in the region where the ductility significantly decreases, and reduces the difference in the absolute value of the ductility between the slab and the ribbon, which causes peeling of the ribbon. The expected lead sheet can now be manufactured.

[0020]

As described above, according to the present invention, even if the composition of the calcium-based alloy slab is difficult to be rolled, the present method can efficiently produce a lead sheet with little variation in quality and its industrial value is great. Can be said.

[Brief description of drawings]

FIG. 1 is a diagram showing a manufacturing process of a lead alloy sheet according to the present invention.

FIG. 2 is a diagram showing a defective rate of a sheet due to a temperature difference between a slab and a ribbon.

FIG. 3 is a diagram showing the defective rate of the sheet for each temperature difference when the amount of calcium contained in the slab is changed.

FIG. 4 is a diagram showing a defective rate of a sheet for each temperature difference when the amount of tin contained in the ribbon is changed.

FIG. 5 is a diagram showing a defective rate of a sheet for each temperature difference when the amount of antimony contained in the ribbon is changed.

[Explanation of symbols]

1 slab 2 rolling mill 3 slab casting machine 4,4 'alloy ribbon Cooling water jet for 5 slabs Cooling water drain for 6 slabs 7,7 'infrared heater Cooling water jet for 8,8 'ribbon 9,9 'Ribbon cooling water drain 10 Lead alloy sheet

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naoto Hoshihara             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Hiroshi Yasuda             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd.

Claims (7)

[Claims] 1. An expanded grid for forming an arbitrary alloy layer on a surface by superposing a ribbon-shaped arbitrary lead alloy foil (alloy ribbon) on a continuously cast lead alloy body (slab) and press-rolling in multiple stages. A method of manufacturing a lead sheet for a grid of a lead storage battery, comprising a step of rolling at a temperature difference between the slab and the alloy ribbon of 150 ° C. or less in a sheet manufacturing process. 2. The method for manufacturing a lead sheet for a grid of a lead storage battery according to claim 1, wherein the temperature difference of the slab is controlled in the first rolling step. 3. The surface temperature of the slab in the first rolling stage is 20.
3. The method for producing a lead sheet for a grid of a lead storage battery according to claim 1, wherein the temperature is not lower than 190 ° C. and not higher than 190 ° C. 4. 4. The lead sheet for a grid of a lead storage battery according to claim 1, wherein at least one surface of the slab or the alloy ribbon is water-cooled to control the temperature difference before the crimping step. Manufacturing method. 5. The slab is a calcium alloy containing 0.1% by weight or more of calcium.
5. A method for manufacturing a lead sheet for a grid of a lead storage battery according to any one of 1 to 4. 6. The method for producing a lead sheet for a grid of a lead storage battery according to claim 1, wherein the alloy ribbon contains tin in an amount of 0.5% by weight or more. 7. The method for manufacturing a lead sheet for a grid of a lead storage battery according to claim 1, wherein the alloy ribbon contains 1% by weight or more of antimony.