JPH03102764A - Positive electrode plate for lead-acid battery - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to improvements in positive electrode plates for lead-acid batteries. Conventional technology and its problems Paste-type electrode plates for lead-acid batteries are produced by kneading lead powder with dilute FiX acid to form a paste, filling a grid with this paste, and then performing aging, drying, and chemical conversion processes. ing. In the drying process, the electrode plate obtained through such a process is
When the paste is used in a battery, cracks occur due to shrinkage of the paste, and the active material is likely to fall off from the electrode plate due to expansion and contraction of the active material due to repeated charging and discharging. Therefore, in order to prevent a decrease in the mechanical strength of the electrode plate active material during the manufacturing process and during battery use, or the lifespan of the lead-acid battery, it has been proposed to mix various types of fibers as reinforcing materials during the paste and kneading process. ．． Conventionally proposed reinforcing fibers include those that have electrical conductivity and those that do not.

Electrically conductive MIltf, such as carbon@fiber, works effectively during the electrode plate manufacturing process, chemical formation process, and the initial stage of the charge/discharge cycle, but it gradually loses its function as it oxidizes and decomposes during the charge/discharge cycle. It cannot be said that it is sufficiently effective in extending the discharge cycle. Fibers that do not have electrical conductivity, such as glass fibers, are effective in preventing the active material from falling off during the charge/discharge cycle life, but do not contribute to improving chargeability during formation. On the other hand, due to the increasing demand for maintenance-free (MP) batteries in recent years, so-called MF batteries, which do not use antimony (Sl)) in lead-acid battery grids, have been commercialized.MP batteries mainly contain lead (Pb). Monocalcium《α
> type alloy is used, and the amount of liquid loss during battery use is smaller than that of conventional PB-SB type alloys. However, the positive electrode plate using pb-at alloy,
During charging and discharging, especially when deep discharge is involved, performance may deteriorate early. This is said to be due to the formation of a highly resistive film, a so-called barrier, at the bulk material interface of the positive electrode lattice. Means for Solving the Problems The present invention uses a lattice made of a pb-Ca alloy as a positive electrode plate for a lead-acid battery, and a glass fiber whose surface is covered with a pb-sb alloy is added to the active material. By using a Pb-Ca alloy as a positive electrode grid, it not only improves the mechanical strength of the positive electrode active material during battery manufacturing, the chemical formability during chemical formation, and the strength of the positive electrode active material during battery use. It also prevents the formation of barriers when used and improves the life performance of MP batteries. EXAMPLES The present invention will be explained below using examples. First, in the process of extruding the molten glass fiber to a thickness of 13 μm in diameter, the molten Pb-3%Sb-0.25% alloy (hereinafter all percentages are by weight) is extruded into the fiber just before the glass fiber hardens. The coverage of the Pb-Sb alloy (ratio of the glass fiber surface covered with the alloy) was 60%. A PB-0.1% Ca-0.5% alloy was used for the grid, and during paste kneading, glass fibers with a length of 3 cm were added to the weight of the positive electrode active material at a ratio of 0, 0.01, 0.1,
0.2, 0.3% (equivalent to Noku Batteries A to E), and for comparison, Pb-3%Sb-0.2 was added to the positive electrode grid.
A total of 6 types of positive electrode plates were made using a 5% n alloy (equivalent to battery F), and a battery with a nominal capacity of 35 A b was made by using a negative electrode plate and a separator made in the usual manner. did.

Regarding these six types of batteries, the pbo. The content, 511R capacity immediately after chemical formation, and the number of life cycles in a life test according to JIS D 5301, which is a deep charge-discharge cycle, were investigated. The results are shown in Table I. Furthermore, in order to investigate the MF characteristics, after the initial capacity test, the battery was charged for 28 days at a battery temperature of 40°C and a charging voltage of 2.4V, and the amount of liquid lost was investigated. The results are shown in Table 2. The lifespan under deep charge/discharge cycles in Table 1 was also significantly improved, and almost the same lifespan performance as the battery (F) using a Pb-Sb alloy for the positive electrode grid was obtained. This is due to the fact that the endo-) type alloy attached to the glass fiber surface acts effectively during charge/discharge cycles.
It is presumed that a similar state would occur if a Pb-Sb-based valley metal was used for the positive electrode lattice.

From Table 2 and Table 1, it can be seen that in the batteries (B to E) using the positive electrode plate according to the present invention to which internal glass fiber was added, the pbo.
As is clear from the content, the chemical formability has improved considerably, but also, despite the use of Pb-Ca alloy in the positive electrode lattice, as shown in Table 2, the glass fiber with h A positive electrode plate with addition of 0.2% has almost the same level of liquid loss as one without addition, and has almost the same MP characteristics, but when 0.3% is added, the amount of liquid loss is slightly larger. MP characteristics deteriorated. The reason for this is [Glass fiber with 'b? It is thought that the amount of a eluted from the ■-a alloy adhering to the surface increased slightly, resulting in a slight increase in the amount of liquid loss. The coverage rate of the pb-sb alloy on the glass fiber surface is determined by the method of spraying the pb-sb alloy on the glass fiber surface.
It is difficult to achieve a coating rate of 80% or more due to the manufacturing method, and if it is less than 30%, the effect of the -3 alloy coating will be reduced, so the coating rate should be 30~30%.
It is appropriate to set it to 80%.

In addition, the diameter of the glass fiber with ■ is 5 to 20 μm from the viewpoint of ease of molding and fiber strength, and the length is 1 to 5 μm from the viewpoint of ease of cutting and dispersibility during paste kneading.
A range of mm is appropriate. Effects of the Invention As detailed above, batteries using a Pb-Ca alloy as the positive electrode grid and a positive electrode plate to which glass fibers whose surface is covered with a Pb-SB alloy have only chemical properties. In addition, the life performance is improved, and the MF characteristics are also superior, so the effects are very large.

Claims (1)

[Claims] 1. Using a lattice made of Pb-Ca alloy, the surface is coated with Pb
- A positive electrode plate for a lead-acid battery, characterized in that glass fiber covered with an Sb-based alloy is added to an active material.