JPS6191874A - Collection body for lead storage battery - Google Patents

Abstract

PURPOSE:To improve the capacity recovery of a collection body after it is left at stand under the overdischarge and discharge conditions by forming the collection body that contains a specific amount of thin near the surface of a lead antimony group alloy grating. CONSTITUTION:A collection body that contains tin near the surface of a lead antimony group alloy grating is formed by adding the lead-tin alloy that contains tin by 8wt% to the lead-antimony alloy that contains antimony by 1.2wt%. As a result, the interfacial characteristics between the collection body and lead paste are improved and the capacity recovery of the collection body can be improved after it is left to stand under the overdischarge and discharge conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improvements in current collectors for lead-acid batteries.

Conventional Structure and Problems Paste-type electrode plates are generally used as the electrode plates of lead-acid batteries. This paste-type electrode plate is made by applying a lead paste containing sulfuric acid and water as main components to a current collector made of lead or a lead alloy using lead powder.

The adhesion between the current collector and the lead paste and the oxidation form at the interface have a large effect on the characteristics of the lead-acid battery. In particular, it is said that the life characteristics of lead-acid batteries are significantly reduced when over-discharged, and the reason for this is precisely due to the interface between the current collector and lead paste. Over-discharge characteristics, which have traditionally been considered a drawback of lead-acid batteries, are desired, and in particular, capacity recovery after being left in a discharged or over-discharged state for a long period of time is desired.

A conventionally commonly used current collector is a cast grid of lead-antimony alloy. Antimony was added in an amount of 4 to 6% by weight mainly to increase the mechanical strength of the current collector. However, on the other hand, antimony has a low water-based overvoltage, which causes self-discharge and liquid loss. Therefore, in order to improve the maintenance-free state, the amount of antimony added was increased from 2.6 to 31. It is now used at a reduced level of 3.0% by weight. If the amount is reduced further than this, the castability deteriorates, which is not practical.

Therefore, in order to further achieve maintenance-free operation, a lead-lucium-tin alloy has been put into practical use as a new lattice alloy that does not contain antimony.

It has been found that in a battery using this lead-calcium-tin alloy as a current collector, capacity recovery after overdischarge can be improved by adjusting the ratio of the active material and #L acid as the electrolyte. However, the capacity recovery property after being left to discharge was not improved.

Thus, for example, at a current of 6 hours, the terminal voltage is 1o,
The phenomenon seems to be different between discharging and leaving the cell discharged to tsV (in the case of e-cells) and overdischarging and leaving the cell in a completely discharged state at an even lower current. It is necessary to improve both characteristics and to obtain maintenance-free performance equivalent to that of lead-calcium-tin alloys in order to further expand lead-acid batteries.

OBJECTS OF THE INVENTION It is an object of the present invention to improve the above-mentioned conventional drawbacks, improve the capacity recovery of lead-acid batteries after being left over-discharged and discharged, and maintain maintenance-free characteristics.

Structure of the Invention In order to achieve the above objects, the current collector for lead-acid batteries of the present invention has the following features:
It is characterized by containing 5% by weight or more of tin near the surface of the lead-antimony alloy lattice.

The antimony content here should be less than 2.0% by weight. Even without antimony, the capacity recovery after over-discharging and discharging for the above purpose will be improved, but the strength of the electrode plates will be significantly reduced. It is preferable to add antimony in an amount of .5 to 1.6N.

Also, if the amount of antimony is less than 2.0]j amount coefficient,
Maintenance-free characteristics are almost the same as those of a lead-calcium-tin alloy current collector, but the cast iron 57\.

The features become poor and it becomes difficult to cast a lattice shape with fine ribs, so if a sheet obtained by rolling a cast plate is extended and made into a lattice shape, this major manufacturing problem will be eliminated.

With the above configuration, maintenance-free characteristics can be obtained from lead-free.
It is equivalent to a lucium-tin alloy, and can significantly improve capacity recovery after overdischarging or being left in a discharged state for a long period of time.

DESCRIPTION OF EMBODIMENTS Next, the features and effects of the configuration of the present invention will be explained by way of embodiments.

A lead-antimony alloy containing 1.2% by weight of antimony (hereinafter referred to as Pb-1,2Sb) was melted into a casting mold with a length of 1 m, a width of 10 cm, and a thickness of 1-0.9 cm.
A lead-tin alloy containing 8% by weight of molten tin (hereinafter referred to as Pb-88n) was added to give a total thickness of 1c1n.
Lead alloy plate A was made as follows.

Next, a Pb-1,2Sb alloy and a Pb-88n alloy are poured into the mold to form a lead alloy plate B, respectively.

I made C.

6.- These three types of cast lead alloy plates A, B, and C were rolled into sheets with a thickness of %1.011 Im, and then subjected to exband processing to form a grid-like current collector. Lead paste was applied to this current collector to create positive and negative polar plates, and three 12V batteries A, B, and C were created for each current collector.

Using the battery prototyped as described above, the following three types of tests were carried out. After one charge, the battery was left at 4 OC for one month. Next, this battery was heated to -15C'300A 6. The battery was discharged to Ov and the remaining capacity was examined. 10.5V at 05 hour rate current
After discharging to 40℃, the battery was left for 3 months at 40C. After discharging at a rate of 5 hours in the same manner as in 3.2, a 10W lamp was connected and left for one week. Then I left it at 40C' for 3 months. Next, after completing a few tests, the battery was charged at 14.8V for 6 hours and discharged at -16C at 300A.

The figure shows the duration of -16C3oOA discharge.

As is clear from the figure, the remaining capacity (symbol 0
) is battery A using the current collector of the present invention and pb-1,2sb.
It is equivalent to battery B using a current collector containing C.
It is about twice as good as P b -8S n. Although the values of A and B were not mentioned in the examples, they are the same as the lead-calcium-tin alloy currently used in maintenance-free batteries, and are the same as the lead-calcium-tin alloy used in conventional batteries (approximately 26 (seconds).

In addition, battery A using the current collector of the present invention and battery B using a Pb-1,2sb alloy are excellent in terms of capacity recovery (symbol Δ) after being left to discharge in No. 2. However, in terms of capacity recovery after over-discharging in No. 3 (indicated by symbol), Battery A using the current collector of the present invention and Battery C using P b -8S n alloy are superior.

As mentioned above, Pb-1,2Sb alloy or pb-8S
Although there are advantages and disadvantages in the characteristics of charging, leaving, discharging, and over-discharging, it can be seen that when the current collector of the present invention is used, all of the characteristics are excellent.

In addition, although the example shows the case of 8% by weight of tin, it was found that a great effect can be obtained if it is 5% by weight or more. However, if it exceeds 30% by weight, the mechanical strength of the current collector becomes brittle, so in practical terms, it is preferably 5 to 30% by weight. In addition, a layer containing tin may be included in the entire layer, but since the material cost of tin is about 20 times more expensive than that of lead, it is better to have a smaller amount from an industrial perspective. It has been found that a layer of approximately 10 μm thick on one side is effective.

Although it is possible to make the layer thinner than this depending on the tin concentration, it becomes difficult to form such a thin layer using an inexpensive method. The present invention does not restrict this tin layer. Furthermore, the method of forming the tin layer has been effective by thermal welding, plasma melting, etc., and there is no restriction on the method of forming the tin layer.

On the other hand, the amount of antimony is preferably 2.0 weight coefficient or less in view of self-discharge characteristics. Particularly when considering the strength of the current collector, 0.5 to 1.6% by weight is light and heavy for automotive lead-acid batteries.

Effects of the Invention As described above, by using the current collector of the present invention, a maintenance-free lead-acid battery with excellent overdischarge characteristics can be obtained.

[Brief explanation of the drawing]

9. Figure 9 is a characteristic diagram showing the remaining capacity of a lead-acid battery according to an example of the present invention after being left uncharged, and the capacity recovery property after being left undischarged and after being left undischarged. Name of agent: Patent attorney Toshio Nakao and 1 other person (4 Akebono - deceased)

Claims (3)

[Claims] (1) Add 5% tin near the surface of the lead-antimony alloy lattice.
A current collector for a lead-acid battery, characterized in that the current collector contains at least % by weight. (2) The antimony content of the lead-antimony alloy is 2
．． The current collector for a lead-acid battery according to claim 1, which has a content of 0% by weight or less. (3) The current collector for a lead-acid battery according to claim 1, wherein the lattice is made of a rolled sheet of lead-antimony alloy subjected to exband processing.