JPS60170158A - Separator for lead storage cell - Google Patents

Abstract

PURPOSE:To improve performance and assembing workability of cells by hardening the periphery of a glass mat made of glass fiber of a specific diameter with an acid-resisting synthetic resin. CONSTITUTION:The periphery of a glass mat made of glass fibers of 0.5-2mum in thread diameter is hardened with an acid-resisting synthetic resin. For example, two glass mats each of 1.5mm. thickness constituted of glass fibers of 0.5-2mum in thread diameter are put one over the other and the side faces are hardened with polypropylene resin to form a separator 3. As the cynthetic resin, instead of the polypropylene, polyethylene and polychlorovinyl having acid- resisting property can be used. In other constitution, a method of hardening the portion of thermosetting varnish adhesive such as epoxy resin protruded from between the plates can be used. The shape of the hardened portion B should be bounded to the area that does not contact the plates and the thickness is adjusted to be the same as the dimention between the plates by press rolling.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improvements in lead-acid batteries, particularly separators for sealed lead-acid batteries that absorb oxygen gas at the negative electrode.

2. Description of the Related Art Structures of Conventional Examples and Their Problems This type of sealed lead-acid battery is desired to have a large capacity as a backup power source and an emergency power source for computers, and the demand for this type of sealed lead acid battery is increasing. As shown in FIG. 1, this battery consists of a positive electrode plate 1 a negative electrode plate 2. Separator 3. Safety valve 4. It consists of a container 6 consisting of an electrolyte and a lid, and an electrolyte is held in positive and negative electrode plates and a separator.

The absorption method for the generated oxygen gas is a cycle in which the 02 gas generated from the positive electrode during charging is absorbed by the change in Pb-+Pt)0 at the negative electrode plate, and the negative electrode begins to discharge, suppressing the generation of H2 gas. This is a configuration that minimizes consumption of electrolyte.

The separator used for this purpose must have a water content of 80% or more for battery performance, and generally a glass mat made of glass fiber with a wire diameter of 0.5 to 2 microns is used.

The water content indicates the proportion of the amount of retained liquid contained in the volume of the glass mant, and indicates the water content when a pressure of 20 KP/6 m2 is applied to the glass mat. The shape of the separator is larger than the size of the electrode plates to prevent short circuits at the sides, bottom, and top.

When a battery with the above configuration was repeatedly charged and discharged, the central part of the electrode plate deteriorated significantly, with the positive electrode plate showing softening of the active material and lattice corrosion, and the negative electrode plate showing deterioration due to oxidation. Figure 2 shows the results of examining the electrolyte concentration (specific gravity) in the separator at the final stage of charging, and Figure B shows the results at the time of complete discharge. During charging, the specific gravity of the upper part of the electrode plate is lower than that of the lower part.

On the other hand, during discharge, the specific gravity at the center of the electrode plate becomes very low.
It can be seen that the electrolyte concentration is non-uniform between the center and the periphery. It can be said that these causes accelerate the deterioration of battery performance. The reason why such a concentration distribution occurs is that the electrode plate area becomes wider due to the large capacity, and that the partial water content of the separator differs. Since the separator in contact with the electrode plate is under a certain pressure, the water content in this part is 80 to 95%, but the peripheral area E that is not in contact with the electrode plate is
Since there is no pressure, the water content is about 120%.

For this reason, a concentration distribution occurs due to the electrolytic solution supplied from the peripheral portion during charging and discharging.

Separators made of glass mats are made by laminating fibers with a wire diameter of 0.5 to 2 microns, but with current technology, the variation in thickness increases when the thickness exceeds 2.01 m, so this Large-capacity batteries like these use several separators stacked on top of each other. However, this caused a significant decrease in workability.

OBJECTS OF THE INVENTION It is an object of the present invention to solve the problems of the prior art and to improve battery performance and workability.

Structure of the Invention The separator for lead-acid batteries of the present invention is characterized in that the periphery of a glass mat made of glass fibers having a diameter of 0.5 to 2 microns is hardened with an acid-resistant synthetic resin. With such a configuration, the distribution of the electrolyte concentration can be made smaller than before, thereby improving battery performance and workability.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 is a plan view and a side view of a separator 3 for a storage battery. This separator is formed by combining two glass mats with a thickness of 1.5 and 1.5 and made of glass fibers with a wire diameter of 0.5 to 2 microns, and hardening the sides with polypropylene resin. To manufacture this separator, two large glass mats are put together, molten polypropylene is poured on top of the mat, cooled and solidified through press rollers, fixed, and then cut. As the synthetic resin for bonding, in addition to polypropylene, acid-resistant materials such as polyethylene and polyvinyl chloride can be used. The portion protruding from the electrode plate may be solidified with a thermosetting resin adhesive such as epoxy resin. The shape of the assimilation part B is such that it does not touch the electrode plates, and its thickness is adjusted using a press roller to be the same as the dimension between the electrode plates.

4A and 4B show another embodiment of the invention. A person's left and right sides and lower part are fixed, and B's left and right sides, lower part, and upper part are all fixed. For B, a trowel is also a good method due to its characteristics, but
It has the disadvantage of reducing workability.

Furthermore, it is also possible to stack two or more glass mats.

Using the separator of the example shown in FIG. 3, a 100 Ah battery was fabricated and evaluated at a 10 hour rate. The electrode plate used has a width of 1
41 x height 138 x thickness: positive electrode 3.1ff, negative electrode 2.
It was set as O#11. Also, the separator is width 160 x height 14
4 x thickness 3.0 mm, and the electrode plate group configuration was 7 positive electrodes and 8 negative electrodes. As a result, the concentration distribution of the electrolyte during charging and discharging is smaller than before, and the trickle charge life test using this battery was also improved by 10 to 20% over conventional B, as shown in Figure 5. The test conditions were 2.3V trickle charging, o, 1C (10 people) discharge every 6 months at an ambient temperature of 25°C.

The batteries that reached the end of their lifespans had deteriorated overall, and there was no difference in the degree of deterioration in the center like in conventional batteries.

Furthermore, in terms of work, mechanization is now possible because separators can be handled more easily by fixing the periphery, compared to the conventional method of wrapping two or more plates on top of each other.

Effects of the Invention As described above, according to the present invention, it is possible to put into practical use a lead-acid battery whose battery performance and workability are improved by solidifying the peripheral portion of the separator with an acid-resistant synthetic resin.

[Brief explanation of the drawing]

Figure 1 is a schematic sectional view showing the configuration of a conventional lead-acid battery, Figures 2A and B are diagrams showing the electrolyte concentration in the separator during charging and discharging, and Figure 3AB is a diagram showing the electrolyte concentration in the separator during charging and discharging. FIG. 4A is a plan view and a side view showing a separator for a lead-acid battery according to an embodiment of the present invention. A plan view of a separator in another embodiment of Bid et al., and FIG. 5 is a life characteristic diagram. 1... Positive electrode plate, 2... Negative electrode plate, 3...
・Separator, B... Solidified area around the separator. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4 Figure 5 Time (pieces)

Claims (1)

[Claims] A separator for a lead-acid battery, characterized in that the periphery of a glass mat made of glass fibers with a wire diameter of 0.6 to 2 microns is hardened with a 4-acid synthetic resin.