JPS5987765A - Electrode for lead-acid battery - Google Patents

Abstract

PURPOSE:To increase life of a lead electrode by making zirconyl phosphate and sodium pyrophosphate contain in an electrode active material and suppressing transfer of lead ion to the outside of the active material by lead ion absorbing ability of zirconyl phosphate. CONSTITUTION:180cc of water, 5wt% of zirconyl phosphate powder to lead powder, and 3wt% of sodium pyrophosphate to lead powder are added to 1kg of lead powder. They are kneaded, then 100cc of sulfuric acid having a specific gravity of 1.40 is added and again they are kneaded to make a paste. The paste is spreaded on the lead alloy grid to form an electrode for a lead-acid battery. By strong absorbing ability of zirconyl phosphate to lead ion, lead ion dissolved during charge-discharge is absorbed near the original place. Therefore, transfer of lead ion to bulk or other place of a plate is suppressed. Thereby, generation of fine crystals is suppressed and life of electrode is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to improvements in electrodes for lead-acid batteries.
In particular, by including zirconyl phosphate in the electrode active material, the life span can be effectively improved.

Conventional configurations and their problems Basically, manufacturing methods similar to the paste method, clad method, and Tudor method are mainly used for electrodes for lead-acid batteries. There are some things. Regardless of the manufacturing method, despite its rich history, there are still some problems that remain unsolved.

One of these is the phenomenon of fineness of the positive electrode active material during charge/discharge cycles, and the resulting softening and shedding of the active material layer. This phenomenon occurs not only in the paste type but also in the clad type surrounded by a porous body of resin or glass, as the bonding force between active material particles weakens due to miniaturization.
Capacity and voltage characteristics deteriorate. Particles that have lost their binding strength fall off and float through the protective body, causing accumulation at the bottom and causing a bottom short circuit, or contacting the negative electrode and being reduced, resulting in accumulation in the form of dendrites. , creating a risk of short circuits at various locations.

At the current technological stage, the presence of antimony is
Although it is said to be effective in suppressing antimony, it cannot be essentially prevented, and even more so, it cannot be avoided in lead-acid batteries, where there is a trend to eliminate antimony from maintenance-free batteries. I don't get it. In other words, in order to improve life characteristics, it is essentially necessary to suppress crystal refinement.

As mentioned above, in order to improve the life characteristics, it is essentially necessary to prevent crystal refinement. One way to solve this problem is to use Pb2''- dissolution and precipitation during charge removal.
Ideally, the bO2 crystals are deposited at the same position where the Pb○2 crystals were before discharge. However, in the current situation where this is difficult, it is effective to at least prevent the dissolved lead ions from leaving the structure and allow them to return to the position before discharging during charging and harm crystal growth. Due to this action, when PbO2 is redeposited,
It is thought that it is possible to prevent miniaturization.

Purpose of the Invention In view of the above, the present invention provides a suitable active material. By adding .

Structure of the Invention The present invention is characterized in that zirconyl phosphate is added to the electrode active material.

Zirconyl on phosphorus has the property of adsorbing many metal ions, and exhibits particularly strong non-phase adsorption power for lead ions. The present invention makes use of this property of zirconyl phosphate to adsorb lead ions that are once dissolved during charging and discharging into the vicinity of the position where they originally existed. However, lead ions are inhibited from migrating offshore or to other positions on the electrode plate, resulting in the effect of inhibiting miniaturization.

If sodium pyrophosphate is included together with this zirconyl phosphate, the above-mentioned effect will be exhibited even more effectively. That is, birophosphoric acid no-da has the property of a metal sequestering agent in that it surrounds metal ions to form a metal complex, producing even greater effects.

Description of Examples To 1 kg of lead powder, 18 cc' of water and 1 g of zirconyl oxide powder were added to the lead powder in 5 parts and 1 part, and after preliminary kneading,
Electrode A was prepared by kneading 100 cc of sulfuric acid with a specific gravity of 1.40 and applying it to a lead alloy grid. Separately, 1 kg of lead powder and 18 kg of water.
0CC, 5 weight ft of zirconyl phosphate powder to lead powder
% and then added 3% by weight of sodium pyrophosphate powder to the lead powder, and after preliminary kneading, sulfur (with a specific gravity of 1.4o) was added.
Electrode B was prepared by kneading glloocx, , and coating it on a lead alloy grid (7).Also, as a comparative example, lead powder 1"9
After pre-kneading K with 180cc of water for 1ft, 100cc of sulfuric acid having a specific gravity of 1.40 was kneaded, and electrode C was prepared by applying the mixture to a lead alloy grid.

Using these electrodes, a battery with a 10 hour rate capacity of about 50 Ah was prepared and subjected to a charge/discharge cycle test.

The charge/discharge cycle test was conducted at a current of 15A, at a depth of 10
The battery was repeatedly discharged at 0 and then charged at 6A for 8 hours. the#
The Wf results are shown in the figure.

As seen in the figure, the ratio 11I9° product C to which the present invention is not applied deteriorates the earliest under the two severe conditions, and A to which zirconyl phosphate is added is overwhelmingly inferior to C. It has a long lifespan, plus zirconyl phosphate.

It can be seen that the lifespan is longer than that of BN and A to which sodium pyrophosphate was added at the same time. Also, regarding the electric ratio characteristics, A,
B did not decrease compared to C.

Effects of the Invention As described above, the present invention provides an electrode for lead-acid batteries that significantly extends the life of the battery without causing a reduction in the discharge characteristics of the battery. It will also contribute to the expansion of lead-acid batteries into applications that require long life, such as electric vehicles and forklifts.

Eight Show comparison.

Claims (2)

[Claims] (1) An electrode for a lead-acid battery, characterized in that the electrode active material contains zirconyl phosphate. (2) An electrode for a lead-acid battery, characterized in that the electrode active material contains zirconyl phosphate and sodium pyrophosphate.