JPS63213264A - Lead storage battery - Google Patents

Abstract

PURPOSE:To improve the overdischarge leaving property by using and incorporating a Pb-Ca family alloy plate and a Pb-Sn family alloy plate to make an electrode base body, and containing an alkaline metal ion, an alkaline earth ion, or a phosphoric acid ion in the electrolyte. CONSTITUTION:On a Pb-0.06 wt.%, Ca-0.3 wt.% Sn alloy plate, a Pb-2.5 wt.% Sn alloy sheet of 0.5 mm thick is laminated and rolled to press the Pb-Sn plate to the Pb-Ca-Sn plate. And an electrode base body of 3 mm thick is produced in a punching, filled with a paste, and aged and dried to make a positive electrode. On the other hand, since the density of sulfric acid of the electrolyte is remarkably reduced and the conductivity of the solution is also remarkably reduced when the battery is overdischarged, the conductivity of not only the grid but also of the electrolyte must be maintained to improve the overdischarge leaving property. As an additive to the electrolyte, in consideration of the influence to the other properties (cycle life, capacity, and the like) of the battery primarily, an alkaline metal ion or an alkaline earth metal ion is preferable. In such a composition, the overdischarge leaving property can be improve remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a method for depositing Sn on the surface of an electrode substrate without using a conventional casting method.
The purpose of this is to improve charge recovery even after a lead-acid battery has been left unused for a long period of time or over-discharged by having it present in the electrolyte. Generally speaking, if a lead-acid battery is left unused for a long period of time or left in an over-discharged state, it becomes unable to be recharged. Conventionally, in order to prevent this situation from occurring, improvements have been made to the lattice alloy of lead-acid batteries.1 For example, reducing the sb content of the electrode substrate to reduce self-discharge;
Pb-C containing no Sb to prevent liquid loss
A-based alloys are also used. Moreover, since it is a material, the grid is coated with a conductor, or the active material is added with a conductor.

Furthermore, when using Pb-Ca alloys, cast lattices are generally used, but the vortex flow is poorer than that of pb-sb alloys, and the strength after casting is inferior to that of pb-sb alloys. It is conceivable to use a rolled sheet with an expanded band process.Problems to be solved by the inventionEven if the grid is coated with a conductor in order to improve the charge recovery after over-discharging, the conductor will not become a conductor. Due to weak bonding with the lattice body or active material, it may be removed from the lattice, or
The conductor itself has poor acid resistance and oxidation resistance, so it has not been put into practical use. In this case, it has been put into practical use to add Sn to the Pb-0o alloy to improve castability and overdischarge characteristics, but Sn is more expensive than Pb. Therefore, the amount added is limited, and the amount limits the performance, making it difficult to use industrially.Furthermore, in actual use of lead-acid batteries, they are not always used fully charged, and in extreme cases. In some cases, the battery is left in a state where there is almost no dilute sulfuric acid.Under such conditions, no matter how much Pb-Ca-Sn alloy is used, charging becomes impossible.

The present invention provides a lead-acid battery that solves all of the above problems.

Means for Solving the Problems The present invention discloses the use of Pb to increase the Sn content on the surface of the lattice compared to conventional lattices (casting, sheet extract).
-0o alloy plate and Pb-Sn alloy plate are first integrated into a plate piece, which is used as a material and the 111 electrode base of a lead-acid battery. This is a lead-acid battery in which similar ions or phosphate ions are present.

If a lead-acid battery is left uncharged for a long period of time, it will become unrechargeable due to self-discharge, and if it is left uncharged after deep discharge, it will also become unrechargeable.

The reason for this is that the internal resistance of the positive electrode plate increases significantly, and the factors causing this increase are probably as follows. When a lead-acid battery is over-discharged, the specific gravity of the electrolyte decreases, and it is even lower near the base inside the electrode plate than at the surface. In this case, the solubility of Pb in the electrode substrate increases, and Pb
When b”? is generated, pbo, which is an active material near the positive electrode substrate,
t becomes unstable as the pH increases, forming a local cell reaction, PbO, +Pb+2H* SO, -1-2P b
S 04 +2 H* 0 Toh tteP b S
Generates O4. At the same time Pb5O, JtP)
, comes to cover the substrate interface. Furthermore, when H,804 is consumed in the above local battery reaction, the positive electrode potential decreases to -400 to -200 mV (VS, HP
/ H, S' t 80-) e light t m" and P
b (Electrode base) The order is ζ so that the local battery reactions of +5O247, Pb5O, +2e- occur synergistically (E*
--370m V vs HS'/HP*8C
a).

A high resistance film is formed by the growth of p b so and the generation of PbOx, which ultimately leads to the inability to charge. Therefore, these high-resistance films form and re/+%-φ goo y
++&11 sheet 4blJ5ma111-1-1111-If-・pbot (active material) or other compound that makes it conductive should be present. It has been previously pointed out that Sn is effective against such overdischarge, and the present inventors
The first step is to add Sn to the Pb-0o alloy as a t-pole alloy element.
It was featured in This effect is not clear, or CaSn or PbxO in the pb matrix.
An intermetallic compound called aySnz is generated, and when the electrode base is anodically oxidized, it is dispersed in the oxide film and maintains conductivity, or sn is oxidized and becomes Sho or S.
It becomes a compound like nO, which has semiconducting properties (n
We believe that having a type semiconductor) will improve charging performance. On the other hand, when the battery is over-discharged, the concentration of sulfuric acid, which is the electrolytic solution, decreases significantly, and as a result, the conductivity of the solution also decreases significantly. Therefore, the overdischarge characteristics are not limited to the lattice (
, it is necessary to maintain the conductivity of the electrolyte. Therefore, as an additive, we first considered the effect on other performance of the battery (life, capacity, etc.), and added 4.
1 Furthermore, during charging, an oxidation reaction occurs on the positive electrode side, electrons flow to the load side, and in the electrolyte, H+ and S07 carry charge from the negative electrode. However, after overdischarging, the pH is 7.
Since they are close to each other, H and 0 increase, and both 5OZ- and H decrease. Therefore, a 5Or-salt cation is required as a charge carrier. Therefore, Table 1 shows the ionic conductivity of various sulfates.
etc.) and alkaline earth metal ions (MP'", Oa"+, etc.) are good. Furthermore, as additives, these substances are inexpensive and easy to obtain industrially.

Chapter 1 Table Example An example of the present invention is shown below.

Pb-0.06 weight 4Ca-0.3 weight JlISrz7)
A Pb-2,5 weight 4Sn alloy sheet with a thickness of 0.5 m was superimposed on the alloy plate and rolled, and the Pb-Sn plate was transformed into a Pb-Ca sheet.
- Pressure-bond to the Sn plate. Then, the thickness is 3f by punching method.
An electrode base of i was prepared, filled with paste, aged and dried to obtain a positive electrode plate.

Chemical conversion was performed and a lead acid battery was assembled to produce a 4V-4Ah battery. In addition, the electrolyte contains Na=SO.

M7SO, H, and PO were each adjusted to a predetermined concentration (0.1 mol/)) and injected into the battery. The lead-acid battery produced in this way was discharged at 1.7Ω for 24 hours, and
2.45 after being left at 5°C. From Table 2, when comparing batteries NcL1 to 7 and M8 to 14, the recovery performance of the rolled plate punched grid is superior to that of the cast product. . This is determined by the Sn content on the surface of the electrode substrate or the 1% of the cast product.
．． This is thought to be because the score is 5 or higher. Also, Nl18~
9.1O111, which is not one of the 14, has an even better charge recovery effect because of the presence of alkali metal ions, alkaline earth metal ions, and phosphate ions.

As a result, not only the effect of Sn in the i&substrate but also the presence of the electrolyte additive is effective. Furthermore, N1112.13. with all combinations of these additives added.
The effect of No. 14 is even greater than that of No. 9.10.11. As a result of the above, considering the improvement of overdischarge characteristics during actual use, Pb-Ca
- It is difficult to use rolled sheets of Sn and Pb-Sn alone,
By coexisting an electrode base with an increased Sn content on the surface of this electrode base and alkali metal ions, alkaline earth metal ions, and phosphate ions, they exert a synergistic effect, and the charge recovery performance is improved without any practical hindrance. I realized that I should make it into something that doesn't exist.

Effects of the Invention As described above, the present invention significantly improves the overdischarge characteristics of lead-acid batteries, and has enormous industrial value.

Claims (1)

[Claims] A Pb-Ca alloy plate and a Pb-Sn alloy plate are integrated to form a plate piece, which is used as a constituent material for an electrode base, and an alkali metal ion or alkaline earth metal ion or phosphorus is added to the electrolyte. A lead-acid battery characterized by the presence of acid ions.