JPS5887757A - Paste type lead-acid battery - Google Patents

Abstract

PURPOSE:To obtain a paste type fluid electrolyte lead-acid battery having good discharge performance and excellent life by bringing a cathode plate into contact with a fine glass mat having a plurality of notches. CONSTITUTION:A fine glass mat 3 obtained by installing a notch 6 is brought into close contact with irregularities of the surfaces of a cathode plate 1, and holding ability of a cathode active mass is increased. This suppresses softening of the cathode active mass. Because the length of a notch is larger more than one order than the diameter of a through hole and loading is decreased, life is improved. The notch is arbitrarily applied in any direction such as vertically, horizontally, and obliquely. Also the length of the notch can be combined variably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paste-type lead-acid battery, and in particular, it is an object of the present invention to provide a paste-type lead-acid battery with even better life performance.

Recently, a glass mat mainly composed of glass fibers with a fiber diameter of 1 μm or less (hereinafter referred to as a fine glass mat) has been used, and most of the amount of electrolyte required for a battery is contained within an electrode group consisting of the fine glass mat and anode and cathode plates. A small-sized sealed paste type lead-acid battery has been proposed, and its effectiveness in preventing the cathode active material from falling off of the fine glass mat has been recognized. Some attempts have also been made to use the fine glass mats in paste type lead-acid batteries having a normal flowing electrolyte with a large amount of flowing electrolyte not retained within the electrode group.

The fine glass mat is extremely effective in preventing the anode active material from falling off, but since it is a very dense mat, it is very difficult to prevent the flowing electrolyte from dispersing between the anode and cathode plates, especially from outside the electrode group. However, it has the disadvantage of significantly reducing the capacity performance of the battery.

As one of the methods to eliminate this drawback,
As shown in No. 3150, a glass mat used as a conventional storage battery mat (hereinafter referred to as ordinary glass mat) mainly consists of glass fibers with a fiber diameter of 10 to 60 μ between a fine glass mat and a cathode plate. intervene,
The idea was to improve the diffusion of the flowing electrolyte. Indeed, in this case, when the thickness of the anode and cathode plates is thin and the discharge current density is low, a discharge capacity equivalent to that of a conventional paste-type lead-acid battery using a glass mat can be obtained. However, if the positive and negative electrode plates of the battery are thick or the discharge current density is high, then the capacity performance will be considerably lower than that of conventional paste type lead-acid batteries that normally use glass mats. There is.

As a method to eliminate this drawback, it has been proposed to provide through holes in the fine glass mat. However, this method has a problem in that when the through holes are large, the effect of preventing the anode active material from falling off is greatly reduced. . On the other hand, when the through-holes are small, the fine glass mat is compressed during handling such as battery assembly, making the through-holes smaller and less effective in reducing capacity performance.Furthermore, the anode active material softens when the battery is charged and discharged. There was a problem in that the through-holes were clogged, and the effect of providing the through-holes was quickly reduced. That is, the method of forming through holes in a fine glass mat has the disadvantage that it is very difficult to control the diameter of the through holes.

The present invention provides a paste-type lead-acid battery with good capacity performance, which does not have the drawbacks of the method of forming through holes as described above, and which retains the effect of preventing the cathode active material from falling off of the fine glass mat. The feature is that a fine glass mat with multiple cut lines instead of holes is brought into contact with the anode plate.

The present invention will be explained below with reference to drawings showing embodiments thereof and experiments that led to the present invention. FIG. 1 is a schematic side sectional view of one embodiment of a paste type lead battery of the present invention, in which 1 is an anode plate, 2 is a positive electrode plate;
is a cathode plate, 6 is a fine glass mat, 4 is a normal glass mat, and 5 is a microporous synthetic rubber plate. FIG. 2 is a schematic front view of the fine glass mat filter shown in FIG. 1, in which score lines 6 are formed. In the case used in the experiment, the cut line 6 was made using a cutter knife. Note that 7 is an electrolytic solution and 8 is a battery container.

Figure 5 shows a battery A according to the present invention using a fine glass mat with a score line of 5 m per anode plate and a total length of 10 m per anode plate, and a cell A according to the present invention. 0.6 instead
The apparent area of the fine glass mat with four through holes is 0.2
0.7 for cell B not according to the invention using a fine glass mat applied at 5% and cell C not according to the invention using only a regular glass mat instead of the fine glass mat.
This is a change in discharge duration in 1 hour rate capacity discharge during a charge/discharge cycle life test of 5C discharge and 125% charge of discharge.

As is clear from FIG. 6, there is almost no difference in the initial capacity of batteries A@B-C. However, in terms of lifespan (life is considered to be when the discharge duration is less than 40 minutes), batteries A and B, both of which use fine glass mats, are more than twice as long as battery C. On the other hand, when comparing Battery A and Battery B, both of which use fine glass mats, Battery B's capacity rapidly decreases to approximately 65% of its initial capacity at the initial 100 cycles, then levels off, and its life span reaches approximately 530 cycles. It became.・
On the other hand, Battery A maintains its initial capacity up to about 400 cycles and has a lifespan of about 600 cycles, indicating that it is superior to Battery B.The reasons for the difference between Battery A and Battery B are as follows. It can be thought of as follows. That is, in battery B provided with through-holes, the through-holes become clogged early due to the softened anode active material, and the diffusion effect of the electrolyte decreases, resulting in a decrease in capacity. Furthermore, battery B having through-holes will be charged and discharged under a high-density electrolytic solution due to clogging, which will shorten the life of the anode plate. On the other hand, in battery A with score lines, the fine glass mat has better adhesion to the irregularities on the anode plate surface and improves retention of the anode active material. It is thought that the life transition is improved because the softening of the anode active material is suppressed, and the length of each score line is more than an order of magnitude larger than the diameter of the through hole, making it less likely to become clogged.

Next, FIG. 4 shows the relationship between the total length of the score line and the initial capacity. In Figure 4, the total length ratio of the score line is the length of the total length of the score line converted per 1 d of anode plate, and the 1-hour rate capacity ratio is the test battery to the initial capacity of battery C. It is expressed as the ratio of the initial capacity of In addition, the length of each cut line for the test batteries was 3 m, 10 m, 50 m, and 60 m, respectively.
- A battery was used which was the same as battery A except for binding. In addition, a battery using a battery with a length of 5 mm per cut line is used, and a battery using a battery D110sII is a battery E1 and O.
-s battery was used (the battery is battery F', and the ' battery using 6Qm battery is battery G).

The following can be seen from Figure 4. That is, when the total length ratio of the score lines is 4fi or less, it can be seen that the longer the length of each score line, that is, the smaller the number of score lines, the worse the capacity. However, when the total length ratio of the score lines becomes 6 or more, the difference in length per score line disappears. Further, when the length of one score line is equal to or less than IL]m, a capacity equivalent to that of battery C can be obtained when the total length ratio of the score line is 4.

In another experiment, a score line with a cut line of 1Q+a+ or more and a cut line total length ratio of 2 to 5 points was made from outside the anode plate contact surface to the anode plate contact surface. By,
The diffusion of electrolyte outside the pole group is improved, and the capacity is on average about 10
% improved.

Note that various embodiments are possible in carrying out the present invention. For example, the direction of the score line can be any direction such as vertical, horizontal, diagonal, etc., and the length of each score line can also be combined in various ways. Furthermore, it is also possible to laminate a fine glass mat with score lines and an ordinary glass mat, a resin synthetic comb, or a synthetic microporous plate, and then abut the ordinary glass mat or microporous plate on the cathode plate side. However, the proportion of the fine glass mat in the gap between the negative and anode plates is preferably 10 to 70%.

As mentioned in 1, the present invention is a paste type storage battery, in which a fine glass mat mainly made of glass fibers with a fiber diameter of 1 μm or less and having multiple cut lines is brought into contact with the anode plate, thereby improving the discharge characteristics. The present invention provides a paste-type lead-acid battery having a fluid electrolyte with good performance and long life performance.
It has great industrial value, especially when applied to paste-type lead-acid batteries for electric vehicles such as electric vehicles and forklifts.

[Brief explanation of drawings]

FIG. 1 is a schematic side sectional view showing one embodiment of the present invention. FIG. 2 is a schematic front view of a fine glass mat with score lines. FIG. 6 is a graph showing the results of a charge/discharge cycle life test of a battery according to the present invention and a battery not according to the present invention. FIG. 4 is a graph showing the relationship between the 1-hour rate capacity ratio and the total length ratio of the score line of the battery according to the present invention. 113. Anode plate 2...Cathode plate 6...Fine glass mat 4...Normal glass mat 5...Microporous plate 6...Score line 7...Electrolyte solution
8...Electricity detection applicant Yuasa Battery Co., Ltd. Figure 1 Figure 2 Figure 3 100200300400500600 Number of charge/discharge cycles (~)

Claims (1)

[Scope of Claims] 1) A paste-type lead-acid battery characterized in that a fine glass mat mainly made of glass fiber with a fiber diameter of 1 μm or less and having a plurality of score lines is brought into contact with an anode plate. 2) The paste type lead-acid battery according to claim 1, characterized in that the total length of the cut lines made on the fine glass mat is 6 lines or more per anode plate. 3) The length of each cut line is 10- or more, and the cut line is made from outside the electrode plate contact surface to the electrode plate contact surface. Paste type lead-acid batteries described in . 4) A product of a fine glass mat and another separator is interposed between the anode and cathode plates 1, and the proportion of the fine glass mat in the gap between the anode and cathode plates is 10 to 70%. Paste type lead 4'@ike according to claim 1.