JPH0322359A - Electrode plate for lead-acid battery - Google Patents

Abstract

PURPOSE:To improve a deep charge cycle life and obtain a long life by making the antimony quantity contained in a thin layer on the side with a lattice lug section larger than that contained in the thin layer on the side with no lug section when a meshy body is divided into two in the height direction by a lattice. CONSTITUTION:An alloy thin layer containing antimony is formed on the surface of a lead alloy sheet, it is expand-machined to form a lattice. When the lattice is divided into two in the height direction of the lattice, the antimony quantity contained in the APQD thin layer on the side with a lug section is made larger than that contained in the PBCQ thin layer on the side with no lug section. When antimony exists on the lattice surface, the lattice surface is reformed, the binding force between the lattice and an active material is improved, part of antimony is eluted into the active material to reform the active material, thus the frequently utilized portion APQD is preponderantly and effectively reformed. The deep charge cycle life is sharply improved and a stable life can be obtained without almost reducing the maintenance-free property.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to improvements in electrode plates for lead-acid batteries, and in particular provides a battery that is both maintenance-free and has a long life under deep discharge.

Conventional technology In recent years, there has been a strong social demand for maintenance-free properties in lead-acid batteries, so generally alloys containing no antimony or containing only a very small amount of antimony are used for the lattice. , so-called maintenance-free batteries are often used. However, while suppressing the amount of antimony improves maintenance-free properties, it tends to reduce the cycle life in deep discharge. As a means of solving this problem, a technique has been proposed in which a thin layer of an alloy containing antimony is applied to the surface of the lattice. In particular, a method in which a thin layer of another anddimon-containing alloy is integrated onto a matrix lattice alloy sheet by rolling and then expanded is an excellent method in that the surface of the lattice can be easily modified.

By sacrificing some maintenance-free properties using the above method, it has become possible to significantly improve the cycle life in deep discharge.

Problems to be Solved by the Invention However, when a large number of batteries were tested, it became clear that there was some variation in the number of deep discharge cycles. A more detailed analysis shows that
It has become clear that the number of lifetimes varies depending on where in the height direction of the electrode plate the thin layer containing antimony is applied.

Antimony applied to the lattice surface degrades liquid reduction characteristics and self-discharge characteristics, and especially when the thin layer containing antimony is not surrounded by the active material and comes into direct contact with the electrolyte, the above-mentioned maintenance-free Characteristics are significantly degraded. In addition, when obtaining a lead sheet by rolling, if antimony is contained in the trimming waste, industrially the base material will contain a trace amount of antimony. It is desirable that no thin layer containing . For the above two reasons, it is effective to apply the thin layer containing antimony not to the entire surface of the expanded part, but only to the central part of the network. Industrially, since the antimony-containing thin layer meanderes during rolling, the width of the antimony-containing thin layer must be smaller than the design value compared to the width developed during expansion.

It has been revealed that variations in the position of the antimony thin layer in the lattice caused by the meandering of the antimony-containing thin layer affect the cycle life in deep discharge.

The present invention aims to minimize variations in cycle life during deep discharge, which is significantly improved by applying a thin layer containing undimon to the lattice surface as described above, and to provide a battery that always has a long life.

Means for Solving the Problems The present invention provides a structure in which a thin layer of an alloy containing antimony is formed on the surface of a lead alloy sheet and an expanded grid is used, and when the grid is divided into two in the height direction of the grid,
The present invention proposes an electrode plate for a lead-acid battery, characterized in that the antimony content contained in the thin layer on the side with the ears is greater than the antimony content on the side without the ears.

The presence of antimony on the lattice surface not only modifies the lattice surface and improves the bonding strength between the lattice and the active material, but also has the effect of elution of some antimony into the active material and modifying the active material. There is. Here, the reason why the deep discharge cycle life is improved by making the antimony content on the side where the ear part of the present invention is arranged higher than the antimony content on the side where the ear part is not arranged is that the part near the ear part This is because the utilization rate of the active material in the area is higher than the utilization rate of the active material in the distant area.

Therefore, it is effective to focus on modifying frequently used parts. However, it is important to add antimony even in areas away from the ears where the utilization rate of the active material is not very high, and as shown in the example below, the antimony content on the side where the ears are not placed is too low. If so, the effect of modification in that area cannot be expected, and as a result, the life of the entire electrode plate will be shortened.

In FIG. 1, the midpoints of AB and DC of plate ABCD are designated P and Q, respectively. Here, the antimony content contained in the rectangular APQD on the side where the ears are arranged is determined by XI. If the antimony content contained in the rectangular PBCQ on the side where no ears are arranged is X2, the present invention satisfies the requirement that 0.7≦X2/
It is proposed to apply a thin layer containing antimony so as to satisfy the condition of XI≦1.0.

Furthermore, the antimony content contained in the thin layer on the surface of the lattice must be 0.4% or less based on the weight of the lattice, and if it exceeds this, the liquid reduction properties will be significantly reduced.

Example The details of the present invention will be explained using examples.

First, we prepared various plates with different values of X 2 / The content of antimony was unified at 0.1% of the grid weight.These batteries were discharged at 25A for 1 hour,
．． A cycle life test was conducted using one cycle as a unit of charging at 8 V (maximum current 25 A) for 5 hours. The battery was discharged at 300 A every 25 cycles, and the number of cycles until the voltage reached 7.2 V at the 30th second was measured. At the same time, the rate of liquid reduction during the life test was investigated.

In FIG. 2, the horizontal axis represents X2/XI, and the vertical axis represents the life cycle index, and the relationship between the two was investigated. Also, in Figure 3, the horizontal axis is
2/XI, the liquid reduction rate index was plotted on the vertical axis, and the relationship between the two was investigated.

As is clear from Figure 2, the maximum number of life cycles is shown when the value of X2/XI is between 0.7 and 1.0, and when X2/XI is less than 0.7 and greater than 1.0. It can be seen that the number of life cycles is low in the range.

We disassembled batteries that had reached the end of their service life and examined the state of softening of the active material, and found that batteries with X2/X+ values of 0.7 or more and 1.0 or less had uniformly softened electrode sheet metal. For X2
/XI = 0.5 battery has intensive softening only at the top of the electrode plate, conversely, X2/XI = 0.5 battery has not softened much at the top, but softening is concentrated at the bottom. Ta. As can be seen from Figure 3, the liquid reduction rate during the life test was
/X It is almost constant regardless of the value of +,
As long as the thin layer containing antimony is surrounded by the active material, it can be determined that the liquid reduction characteristics are the same regardless of the position where the thin layer containing antimony is applied.

On the other hand, we tested how the life in deep discharge and liquid reduction characteristics change depending on the antimony content contained in the thin layer. The results are shown in Figures 4 and 5, respectively. Fourth
As can be seen from the figure, if some amount of antimony is present, the deep discharge life is significantly improved, and no significant change is observed depending on the amount of antimony. However, as shown in Figure 5, the antimony content is 0.
．． If it exceeds 4%, the liquid reduction properties will be significantly reduced. Therefore, the content of antimony contained in the thin layer is preferably 0.4% or less based on the lattice weight.

Effects of the Invention As described above, the present invention is highly effective in providing a battery that significantly improves deep discharge cycle life and has a stable life without substantially reducing maintenance-free property.

[Brief explanation of drawings]

Figure 1 shows the expanded lower grid using the technology of the present invention, and Figures 2 and 3 show the relationship between the value of X 2 / X 1 and the cycle life index and liquid reduction rate index in deep discharge. Figures 4 and 5 are diagrams showing the relationship between the antimony content contained in the thin layer and the cycle life index and liquid reduction rate index in deep discharge with respect to the lattice weight. Points P and Q are the midpoints of sides AB and DC, respectively, and X1...
...Sb contained in the rectangle APQD in Figure 1
l, X2...The amount of sb contained in the rectangle PBCQ in Figure l. Figure 4 5b sld book (Shun No. 5 @I slD book education l!!! (A no.

Claims (3)

[Claims] (1) An expanded lattice with a thin layer of alloy containing antimony on the surface of the alloy sheet is used, and the thin layer containing antimony is present within 90% of the height in the height direction of the mesh. When the grid is divided into two in the height direction of the grid structure, the antimony content contained in the thin layer on the side with the grid ears is the same as that in the thin layer on the side without ears. An electrode plate for a lead-acid battery, characterized in that the antimony content contained therein is greater than or equal to the amount of antimony contained therein. (2) The antimony content contained in the thin layer on the side without ears is 70% or more and less than 100% of the antimony content contained in the thin layer on the side with ears. An electrode plate for a lead-acid battery according to claim 1. (3) The electrode plate for a lead-acid battery according to claim 1 or 2, wherein the total amount of antimony contained in the thin layer is 0.4% by weight or less based on the weight of the lattice. .