JPS5882471A - Sealed lead storage battery - Google Patents

Abstract

PURPOSE:To improve remarkably overcharge durability with no damage of cycle durability by a methd wherein glycerine is made to be contained when compunding paste to fill a grid therewith or the glycerine is stuck to the grid surface to be further filled with ordinary paste. CONSTITUTION:In the illustration, curves A1-A7 correspond to the glycerine contents of the positive pole paste in a battery, 1, 3, 5, 10, 30, 50, 100g/kg. From said illustration it can be seen that in the case of the battery, wherein a mat of glass fiber is used, overcharge durability can be improved when glycerine is contained in the positive plate. Especially the effect is bigger in the battery, wherein glycerine is contained in the positive pole paste, than in the battery, wherein glycerine is stuck to the grid suface, whereby the most desirable contents thereof are known to be 3-50g/kg from the illustration.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sealed lead-acid battery of a limited electrolyte volume type, which uses liquid-impregnated materials made of glass fiber or synthetic resin, and in which only these materials and the electrode plates are impregnated with electrolyte. The purpose is to improve overcharge life.

In lead-acid batteries, the electrolyte sulfuric acid is directly involved in the charging and discharging reactions of the battery, so the amount of electrolyte is a very important factor in sealed lead-acid batteries used in portable power sources. Conventionally, in sealed batteries used for this type of application, methods have been adopted, such as making the electrolyte into a gel form to make it non-fluid, or impregnating it with a mat with good liquid absorption properties. Batteries using the former gel electrolyte are generally effective in overcharging characteristics, while liquid-containing batteries using mats are effective in cycle life characteristics.

The present invention improves the overcharge life characteristics of a liquid-containing battery with excellent cycle life characteristics, and is characterized by containing glycerin in the electrode plate.・As a result of various studies on ways to improve the overcharge life characteristics of liquid-containing type batteries, the inventors of the present invention found that they included glycerin during paste kneading and filled the lattice with it, or attached glycerin to the surface of the lattice. , by filling it with regular paste, etc.
It has been found that batteries manufactured by containing glycerin in the positive electrode can significantly improve overcharge life without impairing cycle life.

The present invention will be explained below with reference to Examples.

Glycerin was added to a positive electrode paste for lead-acid batteries prepared using a conventional recipe, and the mixture was kneaded. That is, lead powder and lead oxide powder are mixed and kneaded with water and sulfuric acid, and 5 parts of lead powder and lead oxide powder (hereinafter this mixture will be referred to as lead powder) are mixed with 1 part glycerin to 9 parts glycerin. 3,5°10.30,50.1001
9 were added and kneaded continuously. At this time, when the amount of glycerin increases, the fluidity of the paste improves, especially when the amount of glycerin increases.
When it reaches y/Kg, it becomes almost slurry-like, and in this state, workability I becomes poor. These pastes are filled into a positive electrode grid using the usual method, dried, aged, and chemically formed to form an electrode plate.
A normal negative electrode plate is used as the counter electrode, a glass fiber liquid-impregnated mat is placed between the plates, and after inserting it into the battery case, an appropriate amount of sulfuric acid with a weight of 1.30 is added and the sealed battery is immersed horizontally. However, before the glycerin dried, a normal paste was filled, and a battery was manufactured in the same manner as Battery A. The concentration of the glycerin solution was determined by the volume ratio of 0 parts, 30 parts, 50 parts, and 80 parts of water to 100 parts of glycerin. Battery C is a paste containing 10f/Kg of glycerin.

A grid immersed in a solution consisting of 100 parts of glycerin and 30 parts of water was filled and then manufactured using a conventional method.

For comparison, a battery using a glass fiber mat without glycerin in the positive electrode was compared with a battery using a gel electrolyte made from a mixture of D1 sulfuric acid and silica.゜□ A battery containing 30 F//Ky is designated as E.

These batteries have a configuration of 2 positive plates and 3 negative plates and have a capacity of 10
The hourly discharge capacity is approximately 3.0 Ah.

Repeat charging and discharging for these batteries for 3 cycles,
The discharge capacity of the cycle was taken as the initial capacity, and the following evaluations were made.

The battery was charged in an atmosphere of 20'C with a constant voltage of 0.3A for 14 consecutive days, and then discharged to check the discharge capacity.

This is 1 cycle (1 cycle, the discharge capacity is 50% of the initial capacity)
The life of the battery was defined as the time when the battery reached 1, and the overcharge life was evaluated.

Examples of the results are shown in Figures 1 and 2. In the figure, song 1fsA
1 to A7 correspond to 9 for the glycerin content of the positive electrode paste in battery A of 1.3, 5, 10, 30, 50° 100 f/, and curves B1 to B4 correspond to 9 for the glycerin content of the positive electrode paste in battery B. O parts of water to 100 parts,
The characteristics of batteries corresponding to 30 parts, 50 parts, and 80 parts are shown.

Songs IIJC and D show the characteristics of batteries C and D, and curves E1.
E2 shows the characteristics of a battery in which the glycerin content in the positive electrode paste in battery E is 5.30 fl/Kg. It can be seen that the overcharge life of the batteries can be improved.

In particular, when it is contained in the positive electrode paste, the effect on the battery adhered to the grid surface is greater, and the amount of glycerin g4. It is. Furthermore, it can be seen that adhesion of glycerin to the lattice and addition of glycerin to the active material are particularly effective.

Note that the initial capacity of the A7 battery is small, and the effect of adding glycerin is not significant in gel type batteries.

The details of the cause of this difference between gel-type and liquid-containing batteries are unknown, but it is possible that there is a difference in the expansion of the electrode plates and contact with the electrolyte, or the distribution of the electrolyte within the battery. It is conceivable that this may occur.

A similar effect can be obtained when a liquid-impregnated material made of synthetic resin fibers or a liquid-impregnated material mixed with glass fibers and synthetic resin fibers is used instead of the glass fiber mat.

[Brief explanation of the drawing]

FIGS. 1 and 2 show the overcharge life characteristics of batteries using various positive electrodes.

Claims (2)

[Claims] (1) A sealed lead-acid battery, which is a liquid volume limited type lead-acid battery in which a liquid-impregnated material is impregnated with an electrolytic solution, and the positive electrode contains glycerin. (2) The content of 1 glycerin is 3 to 1 lead powder of the positive electrode.
5 oy.