JPH02262255A - Lead-acid battery - Google Patents

Abstract

PURPOSE:To prevent the corrosion and break of an anode material by constituting one or all of an anode grating, a plate group connection part and a polar column with lead or lead alloy having the specific content of antimony and iron respectively. CONSTITUTION:In an anode absorption type lead acid battery having one or all of an anode grating including a plate lug part, a plate group connection part and a polar column made of lead or lead alloy, the content of antimony as impurities in the aforesaid material is kept at 20ppm or less and the content of iron also at 20ppm. According to the aforesaid construction, the concerned material is hardly subjected to corrosion and be comes free from a break, even in a severe oxygen atmosphere during the use of an anode absorption type lead acid battery.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of Application The present invention uses a cathode to absorb oxygen gas generated from an anode during charging. This paper relates to the improvement of so-called cathode absorption lead-acid batteries.

Conventional technology In cathode absorption type lead-acid batteries, metal lead, which is the cathode active material, absorbs oxygen gas generated during charging or self-discharging, which prevents the internal pressure of the battery from increasing due to gas generation.
It has the function of suppressing the decrease in electrolyte. In selecting alloys for the grid, plate group joints, and pole columns to achieve this function, the following points should be considered: - Hydrogen overvoltage is high, and water decomposition in the electrolyte may occur when the battery is charged.

-Added elements do not move to the cathode and cause self-discharge.

The alloy composition is determined with this in mind.

In this way, cathode absorption type lead-acid batteries have little loss of electrolyte during use, eliminating the need for troublesome water replenishment work and allowing storage batteries to be sealed. Furthermore, by sealing the battery, harmful gases are no longer emitted outside the battery during use, making it easier to use the battery indoors.

Problems to be Solved by the Invention However, during use of a conventional cathode absorption type lead-acid battery, especially in a situation where it is constantly being charged such as in standby use, the cathode pole, cathode grid body, cathode grid ears, Alternatively, there was a phenomenon in which rapid corrosion progressed at the joints of the cathode plate groups, causing some of the above members to break. During use, a cathode absorption lead-acid battery is always filled with oxygen gas generated from the anode. Therefore, not only the cathode active material that has the function of absorbing oxygen gas, but also the cathode grid, cathode plate group joints, and pole columns are constantly exposed to oxygen.
It is assumed that this causes corrosion and breakage of the cathode member. Based on this assumption, various studies have been conducted, but no clear cause has been identified.

A detailed analysis of a conventional cathode absorption lead-acid battery in which corrosion of the cathode material progressed during standby use, leading to the material breaking, revealed that one part of the battery had suffered corrosion. It was found that antimony and iron, which were not intentionally added, were found to be present in higher amounts than in areas where they were not added. Furthermore, as the amount of antimony and iron increases, the amount of corrosion increases at an accelerated pace, and controlling the amount of antimony and iron, which was previously considered to be a very small amount with no particular effect, is the key to preventing corrosion of cathode members. It turned out to be important.

Means for Solving the Problems Therefore, the present invention applies a cathode absorption type, does not add antimony and zinc to the battery system, and removes the cathode grid body including the electrode plate ears, the electrode plate group joints, and the pole pillars. In a lead-acid battery in which any or all of these are made of lead or a lead alloy, the antimony content of the above members i 201) P! 1 or less, and the iron content 'i is 20 ppm or less.

The amount of antimony contained as an impurity in the working cathode grid, electrode plate group joints, and pole pillars is suppressed to 20 ppm or less.

Moreover, by reducing the total iron content to 20 ppm or less.

Even in the harsh oxygen atmosphere during use of cathode absorption lead-acid batteries, the relevant components are less susceptible to corrosion and will not break. Therefore, the reliability of the cathode absorption type lead-acid battery can be significantly improved.

Example The present invention will be explained in detail below.

Figure 1 shows the configuration of a cathode absorption lead-acid battery. In the figure, 1 is the cathode plate group joint, 2 is the cathode grid, 3 is the electrode tab, 4 is the cathode pole, 6 is the anode plate, and 6 is the separator.〇To clarify the effects of the present invention , cathode plate group joint part 1
The amount of antimony and the amount of iron contained in 150 ppm,
60ppm, 30pp! II, 20ppm%6p
The time required for this part to break due to corrosion was measured instead of pm. A cathode absorption lead acid battery with a voltage of 12 V and a capacity of 24 μh was used in the test, and changes in the storage battery capacity were measured every month while charging at a constant voltage of 13.8 V. Note that the ambient temperature was 40°C.

The above results are shown in FIGS. 2 and 3.

Figure 2 is a diagram showing the capacity transition of some storage batteries in the above test, and Figure 3 shows the period until the storage battery capacity suddenly decreased in the above test, and the change in capacity at the cathode plate group junction. It is a figure showing the relationship with the amount of antimony contained. As can be seen from Figure 3, when the amount of antimony was 150 ppm, the capacity decreased in one month regardless of the amount of iron. Further, although there was a slight difference depending on the amount of iron, when the amount of antimony was 30 ppm, the capacity decreased within 1 to 3 months. When these storage batteries were disassembled and all causes of capacity reduction were investigated, it was discovered that the joints of the cathode plates in each storage battery were corroded and fractured.

However, in the region where the amount of antimony is 6 to 20 m)pm, as the amount of iron decreases, the period until the capacity decreases becomes longer.
) XI showed a decline in capacity after 18 months.

As a result of disassembling storage batteries with an antimony content of s ppm and 20 ppm and investigating the cause of their capacity decline, it was found that the iron content was 30 to 20 ppm.
In all of the 150 ppm storage batteries, corrosion and breakage were observed at the joints of the cathode plate groups.

However, in the storage batteries with iron content of 6 ppm and 20 ppm, the cause of the decrease in capacity was a short circuit caused by the anode, and no corrosion breakage of the cathode member was observed.

Effects of the Invention As described above, the cathode absorption type lead-acid battery according to the present invention does not contain antimony exceeding 20 ppm in the cathode grid, electrode plate group joints, and pole columns, and does not contain iron exceeding 20 ppm. Therefore, the above-mentioned members do not corrode or break during use of the storage battery, and the amount of electrolyte and self-discharge, which are the most important functions for a cathode absorption type storage battery, is also small. Therefore, it has the effect of significantly improving the reliability of the cathode absorption type lead-acid battery.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of a cathode absorption lead-acid battery according to an embodiment of the present invention, and FIG. 2 is a change in battery capacity during a continuous charging test in a 40°C atmosphere conducted to demonstrate the effects of the present invention. Figure 3 shows the relationship between the amount of antimony and iron contained in the cathode plate group assembly and the period until the storage battery capacity suddenly decreases in the same continuous charging test in a 40℃ atmosphere. It is a diagram. DESCRIPTION OF SYMBOLS 1... Plate group joint part, 2... Cathode grid body, 3... Pole plate lug, 4... Pole column, 6...
... Anode plate, 6 ... Separator. Name of agent: Patent attorney Shigetaka Awano and 1 other person1-
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Claims (1)

[Claims] A lead-acid battery characterized in that any or all of the cathode lattice, the electrode plate group joints, and the poles are made of lead or a lead alloy with an antimony content of 20 ppm or less and an iron content of 20 ppm or less.