JPH05135757A - Lead-acid battery - Google Patents

Abstract

PURPOSE:To prevent an internal short circuit between electrode plates due to the breakage of a bag-like separator side section and provide a battery having a long life by specifying the width size of an incorporated positive electrode plate and the inner size of a bag-like separator to a proper ratio in the lead-acid battery using a cast lattice made of a lead alloy for the positive electrode plate and incorporating the positive electrode plate in the bag-like separator. CONSTITUTION:The width size of a positive electrode plate against the inner size of a bag-like separator is set to 96% or below.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a lead storage battery, and more particularly to an electrode plate and a separator for protecting the electrode plate.

[0002]

2. Description of the Related Art In recent years, a lead storage battery having a structure in which a separator has a bag shape and contains either a positive electrode plate or a negative electrode plate has been put into practical use. In this type of battery, it is most common to fold the separator into two pieces, cut the electrode plate so that it is slightly larger than the electrode plate contained therein, and join the side parts by some method to form a bag. This technology is more effective in preventing internal short circuits at the bottom and sides than when using a conventional flat separator.

By the way, in the case of using the bag-shaped separator, since the side portions of the separator are joined together, the width dimension of the electrode plate must be made smaller than that in the case of using the flat separator, and the capacity or voltage characteristic of the battery is deteriorated. The problem arises. In order to minimize this decrease, the current situation is that the vicinity of the side of the included electrode plate is also joined to the separator. Specifically, the width dimension of the electrode plate is 9 times the inner dimension of the bag-shaped separator.
It is generally 7% or more and less than 99%.

[0004]

Recently, the environment in which lead-acid batteries are used has become severe. For example, lead-acid batteries for automobiles have been used at high temperatures as the performance of engines has increased. Under these circumstances, a large amount of overcharge current flows even during constant voltage charging, and the corrosion of the positive electrode grid significantly progresses, and at the same time the electrode plate expands.

When a cast grid is used for the positive plate, the plate expands especially in the lateral direction. Here, when the positive electrode plate is enclosed in the bag-shaped separator, and the above-mentioned electrode plate has almost no dimensional allowance in the bag-shaped separator, the positive electrode plate expands to be equal to or larger than the inner size of the separator. As a result, the positive electrode plate may damage the side portion of the bag-shaped separator and may even cause an internal short circuit.

When the lead alloy cast lattice is used for the positive electrode plate, the positive electrode plate expands in the lateral direction regardless of the composition of the lattice alloy.

Conventionally, the ambient temperature of a lead storage battery has not been so high, and such a problem has hardly occurred. However, due to the recent increase in the operating environment, the above point has been highlighted as a new subject.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above problems of a battery having a structure in which a lead alloy casting grid is used for a positive electrode plate and the positive electrode plate is enclosed in a bag-like separator, and a long-life battery is provided. Specifically, the width of the positive electrode plate contained in the bag-shaped separator is 9 times the inner size of the bag-shaped separator.
It should be 6% or less. It is more preferable to set it to 96% to 93% in consideration of the electrode plate capacity.

[0009]

In the present invention, the width dimension of the positive electrode plate 2 shown in FIG.
When the inner dimension of the bag-shaped separator 1 that mechanically seals the left and right ends to form the joint portion 3 is B, the condition of A / B ≦ 0.96 is satisfied.

When a material having no elasticity is used for the bag-shaped separator, the side of the separator is more likely to be damaged than the separator having elasticity due to expansion of the positive electrode plate. The setting with the width dimension is extremely effective.

The present invention is a highly effective technique in which a lead alloy casting grid is used for the positive electrode plate and is enclosed in a bag-like separator. The grid obtained by machining the positive electrode plate by expanding or the like is used. In the case of using, if the negative electrode plate that does not expand due to repeated charging / discharging is used as the counter electrode, there is no problem even if the technique of the present invention is used.

When the technique of the present invention is used as compared with the conventional technique, the battery capacity or the voltage characteristic is slightly lowered, but an internal short circuit due to damage to the side portion of the bag-shaped separator can be prevented. That is, the present invention provides a battery having a long life even if the initial characteristics such as electric capacity are sacrificed.

[0013]

EXAMPLES The effects of the present invention will be described below with reference to examples.

Prepare a positive electrode plate using a lead alloy casting grid,
Each of the positive electrode plates was enclosed in a separator having an inner size. A battery having a 5 hour rate capacity of 48 Ah was prototyped with this configuration, and an overcharge test was performed at a high temperature. Ratio of width dimension of positive electrode plate to inner dimension of bag-shaped separator: A / B is 0.99 respectively
The batteries (Battery 1), 0.98 (Battery 2), 0.97 (Battery 3), 0.96 (Battery 4), and 0.95 (Battery 5) were prepared. It was overcharged at a charging voltage of 2.5 V / cell at 75 ° C. After overcharging for 110 hours, the battery was discharged at 300 A, and it was judged as the life when the voltage became less than 7.2 V at 30 seconds. The result is shown in FIG. Batteries 1, 2 and 3 have a shorter life than batteries 4 and 5
Second-second voltage dropped sharply.

When the battery which had reached the end of its life was disassembled and analyzed, it was found that the separator side of battery 1, battery 2 and battery 3 was damaged, resulting in an internal short circuit. On the other hand, batteries 4 and 5 did not show any damage on the side of the separator, and had reached the end of their lives due to lattice corrosion.

As described above, according to the present invention, it is possible to prevent the internal short circuit due to the breakage of the side portion of the bag-shaped separator.

As the width of the positive electrode plate 2 is made smaller, the side portions of the separator are less damaged, but the amount of active material is also reduced and the capacity is reduced. Therefore, the lower limit of the A / B ratio should be 93%. Is.

[0018]

INDUSTRIAL APPLICABILITY As described above, the present invention is extremely effective in providing a battery having a long life by preventing an internal short circuit due to side damage of the bag-shaped separator.

[Brief description of drawings]

FIG. 1 is a diagram showing a dimensional relationship between a positive electrode plate of the present invention and a bag-shaped separator.

FIG. 2 is a diagram showing the results of an overcharge test of various batteries constructed according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bag-shaped separator 2 Positive electrode plate contained in the bag-shaped separator 3 Joining part for making a bag

Claims (2)

[Claims] 1. A structure in which a positive electrode plate using a lead alloy casting grid is enclosed in a bag-shaped separator, and the width dimension of the positive electrode plate is 96% or less of the inner dimension in the width direction of the bag-shaped separator. Characteristic lead acid battery. 2. The lead storage battery according to claim 1, wherein the separator is made of a material having no elasticity.