JPS58169772A - Plate for lead storage battery - Google Patents

Abstract

PURPOSE:To eliminate the early attenuation of capacity even with a tight weight and in a repetition of deep charge and discharge, by overlapping a pure lead or lead alloy layer comprising no antimony and a lead alloy layer comprising antimony each other alternately, while having an active material maintained on a base body made up so as to comprise no antimony on its topper surface. CONSTITUTION:Either part of a pure lead sheet 1 comprising no antimony and a lead alloy sheet 2 comprising 2.5% of antimony are alternately overlapped to each other into five layers in total which are put together so as to cause the pure lead sheet 1 to be placed on a topper of the five layers, and a positive plate is produced with a base body obtained in a process of expanding the sheet. A single cell is made up of the the following process that four positive plates and five negative plates whose each size is almost identical to each of the former are alternately overlapped one after the other.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in plates for lead-acid batteries, particularly lightweight and maintenance-free lead-acid batteries.

In recent years, lead-acid batteries have become maintenance-free, and instead of the conventional lead alloys that contain autimony, lead-acid batteries that use lead alloys that do not substantially contain antimony, such as calcium alloys and strontium alloys, are now available as base plates for their electrode plates. It is being actively developed.

On the other hand, in order to reduce the weight of lead-acid batteries, the manufacture of base bodies, which had previously relied on casting methods, is shifting to manufacturing by mechanical processing such as expansion processing of lead alloy sheets, and gravity casting It has now become possible to manufacture extremely lightweight substrates that were previously impossible.

However, maintenance-free lead-acid batteries that use a substrate obtained by machining a lead alloy sheet that does not substantially contain antimony lose their capacity quickly after repeated deep charging and discharging. If it is too large, it has the disadvantage that no discharge is possible. The cause of this is that there is an electrically inert resistive coating (mainly composed of lead sulfate) on the interface between the anode active material and the base made of a lead alloy that does not substantially contain antimony, which is the current collector of the anode plate. It is said that this is due to the formation of

Therefore, Japanese Patent Application No. 56-26461, Japanese Patent Application No. 56-4
No. 5058 etc., the surface area of the substrate is increased by blasting the surface of the expanded substrate,
Measures have been proposed, such as delaying the time it takes for the substrate surface to be coated with a resistive film generated by deep charging and discharging.

However, this mechanical means is not suitable as a fundamental solution, and it cannot be said to be a very preferable means considering the increase in manufacturing costs.

An object of the present invention is to provide an electrode plate for a lead-acid battery that is lightweight, has maintenance-free characteristics, and does not lose its capacity early even after repeated deep charging and discharging.

In order to achieve the above object, the present invention alternately stacks pure lead or lead alloy layers that do not contain antimony and lead alloy layers that contain antimony, and the outermost surface is made of pure lead that does not contain substantially antimony. Alternatively, an active material is held on a base comprising a lead alloy layer.

The reason for adopting this configuration is that the presence of a pure lead or lead alloy layer that does not substantially contain antimony on the outermost surface of the substrate prevents the elution of antimony from the antimony-containing lead alloy layer into the electrolyte. This is because antimony suppresses precipitation on the cathode plate, and at the interface between the substrate and the active material, antimony improves the adhesion between the two and prevents the formation of an electrically inactive resistance layer.

Examples of the present invention will be described below.

In this example, as shown in FIG. A lead alloy sheet with a thickness of 1.2 wm was used, in which a total of five layers were bonded so that the pure lead sheet 1 was on the outermost surface. Using a substrate obtained by expanding the sheet, an anode plate having a size of 125 m x 105 m and a thickness of 1.5 sm was manufactured according to a conventional method. Four anode plates and five cathode plates of approximately the same size were stacked alternately with separators in between to form a single cell, and dilute sulfuric acid with a specific gravity of 1.28 was injected as an electrolyte.

For comparison, a conventional maintenance-free calcium alloy (0.07 ca-0.7 Sn-0.02
1AA! A unit cell was constructed in the same manner as in the example except that an anode plate was manufactured using a substrate obtained by expanding the remaining Pb) sheet.

The results of the charge/discharge cycle test for the above two types of single cells are shown in FIG. 2. In the test, discharging at 20A1h and charging at 5A5h were repeated, and the discharge duration until the terminal voltage reached 1.75V during 20A discharge was measured.

As is clear from FIG. 2, the unit cell of the example (curve a)
Compared to the conventional product (curve b), the discharge capacity decreases less due to repeated charging and discharging, and the discharge capacity is larger. It can also be seen that the cell life of the example cell can be more than twice as long as that of the conventional product.

That is, as can be seen from the enlarged view shown in FIG. 3, the base of the anode plate in the present invention has an antimony-containing lead alloy layer 2' formed between pure lead layers 1' in the expanded cross section. Therefore, it is thought that even when deep charging and discharging were repeated, there was no early capacity decay because the adhesion between the antimony-containing lead alloy layer and the active material was good.

In addition, to ensure maintenance-free characteristics, the cell of the example and the conventional product were continuously charged at a constant voltage of z5V at 25°C for 500 hours.As is clear from Fig. 4, the cell of the example ( There was almost no difference between curve C) and the conventional product (curve d). Is this about it? It was found that by forming a pure lead layer containing substantially no antimony on the outermost surface of the substrate, the elution of metallic antimony can be suppressed to an almost negligible extent, and the present invention has sufficient maintenance-free characteristics. I can say that.

In the above example, pure lead containing substantially no antimony was used. However, lead alloys containing substantially no antimony, such as calcium alloys, strontium alloys, and sodium alloys, may be used. A material that can be formed may be appropriately selected and used. In addition, although an example using D with an antimony content of 2517) was shown as a lead alloy containing antimony, the same effect as in the example can be obtained by using an appropriate amount. Is possible.

As described above, the present invention is extremely superior in that it has a particularly large effect of improving the life of a maintenance-free lead-acid battery during relatively deep repeated charging and discharging, and also has sufficient maintenance-free performance.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a lead alloy sheet used for manufacturing the substrate of an anode plate in one embodiment of the present invention, Fig. 2 is a curve diagram showing the results of a charge-discharge cycle test of a lead-acid battery, and Fig. 3 is a cross-sectional view of a lead alloy sheet used for manufacturing the substrate of an anode plate in an embodiment of the present invention. 4th enlarged perspective view of the main part of the base of the anode plate in one embodiment
The figure is a curve diagram showing current changes during constant voltage overcharging of a lead-acid battery.

Claims (1)

[Claims] An active material is applied to a substrate in which pure lead or lead alloy layers containing substantially no antimony and lead alloy layers containing antimony are alternately stacked to form a pure lead or lead alloy layer containing substantially no antimony on the outermost surface. Pole plates for lead-acid batteries that hold.