JPH0249355A - Manufacture of sealed lead-acid battery - Google Patents

Abstract

PURPOSE:To keep the utilization of a positive active material at a high level and to retard the early deterioration of cycle life by mixing a specified amount of red lead oxide with paste for a positive plate, and applying a specified value of pressure to a plate group. CONSTITUTION:A positive grid is coated with paste prepared by mixing 20-40wt.% red lead oxide with lead powder comprising lead and lead oxide. A plate group is accommodated in a container, and an electrolyte is poured therein, then pressure is applied so that a load of 35-55kg/dm<2> or less is applied to plates and separators. By adding red lead oxide to the positive active material, the utilization of the active material is kept at a high level. Conversion of the active material powder into its finer powder is prevented by increasing compression ratio of the separator. Early deterioration of cycle life is therefore retarded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a sealed lead acid battery.

Conventional technology Conventionally, in lead-acid batteries, it has been possible to improve the utilization rate of the positive electrode active material by adding red lead to the positive electrode active material, and an increase in initial capacity as shown in Figure 3 has been observed. Ta. A has no red lead added, C and D have 40wt red lead.
FIG. 3 is a diagram showing the relationship between the discharge time and the terminal voltage at 25'C, 0.25CA for a battery containing 0.0% of the oxidation rate.

Problems to be Solved by the Invention Regarding lead-acid batteries using a positive electrode plate containing red lead, with conventional group pressure, the cycle life decreases prematurely as shown in C in Figure 2 due to the miniaturization of the positive electrode active material. There was a problem in that it caused

Batteries A, C, and D are charged at a constant voltage of 7.35V/Ma.
Charging for 6 hours at x 0.4CA, and discharging at 25℃
．． 25CA15.25Vend.

The purpose of the present invention is to solve the above-mentioned problems, and to provide a sealed lead-acid battery that can suppress early deterioration of cycle life while maintaining the improvement in utilization rate by adding red lead to the positive electrode active material. This is what we are trying to provide.

Means for Solving the Problems In order to achieve the above objects, the present invention uses a base containing 20 to 40 wt% of lead mixed in lead powder made of lead and lead oxide as a paste to be applied to the positive electrode grid. After installing the electrode plate group including this positive electrode plate in a battery case and pouring electrolyte (dilute sulfuric acid) into the electrode plate and separator, 35 g/
The method for producing a sealed lead-acid battery was such that a group pressure of 55 Kg/d or less was applied above 55 Kg/d.

Function In the present invention, as described above, a group pressure is applied so that a load of 35 to 55 Kg/drn is applied to the electrode plate group and separator in the battery case. By increasing the compression ratio of the separator, it is possible to prevent the fineness of the positive electrode active material from becoming fine while maintaining the improvement in the ratio, thereby suppressing an early decrease in the cycle life.

Example 6 In a V6.5Ah (20HR) type sealed lead-acid battery, A, B, C, D, E, F as shown in Table 1
Six types of sealed lead-acid batteries were prototyped and cycle life tests were conducted. In addition, for the three types of sealed lead acid batteries A and C1D, after carrying out a capacity test at 0.25CA,
A cycle life test was conducted. Lifespan is 50% of initial capacity
I took the time when it became below. The thickness of the positive electrode plate and negative electrode plate is the same for all batteries, and the positive electrode plate thickness is 3.25 mm.
, the negative electrode plate thickness is 1.89 mm, and 1j of the battery case width is 27.
It is 4mm. The separator used was a stack of two glass fiber separators with a fiber diameter of 0.7 μm and a fabric weight of m I 55 g/rrH”.As for the negative electrode plate, one with the same specifications was used.

Table 1 In Table 1, the separator thickness in the dry state is 20 g/
dm'' thickness when pressurized, and the load applied to the separator represents the load applied to the separator containing electrolyte (dilute sulfuric acid) after being assembled as a battery.

The initial capacity test of each battery is shown in FIG. 3, and the results of the cycle life test are shown in FIGS. 1 and 2.

From FIG. 2, it can be seen that the battery according to the example of the present invention has a large capacity and excellent cycle life characteristics.

From Figure 1, the same effect can be obtained if a load of 35 kg/drn or more is applied to the separator containing sulfuric acid in the battery, but due to the battery assembly process, the upper limit is 55 g/drn. ″ or less.

Effects of the Invention As described above, according to the present invention, 20 to 40 wL% of red lead is mixed into the paste of the positive electrode plate, and the group pressure applied to the electrode plate group is reduced to 35%.
~55 Kg/dm'', it was possible to maintain an improvement in the utilization rate of the positive electrode active material, and at the same time, it was possible to suppress an early decrease in the cycle life due to the miniaturization of the positive electrode active material.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between the load applied to the separator in the battery and cycle life, Figure 2 is a diagram showing the relationship between the number of cycles and discharge duration, Figure 3 is a diagram showing the results of the initial capacity test, and Figure 4 is a diagram showing the relationship between the number of cycles and discharge duration. FIG. 3 is a diagram showing the relationship between load and the thickness of the separator used in this experiment.

Claims (1)

[Claims] (1) As the paste to be applied to the positive electrode grid, use a paste containing 20 to 40 wt% of red lead mixed into lead powder made of lead and lead oxide.
After injecting dilute sulfuric acid), heat the electrode plate and separator to 35K.
A method for manufacturing a sealed lead-acid battery, characterized by applying a group pressure such that a load of 55 kg/dm^2 or more is applied to the battery.