JP2001143744A - Lead storage battery - Google Patents

Abstract

(57) [Summary] [Purpose] To fully demonstrate the function of a liquid level sensor until the life of a lead storage battery is reached. The present invention relates to a lead-acid battery provided with a see-through type liquid level specific gravity sensor, wherein a positive electrode grid made of a lead-antimony alloy, a negative electrode grid made of a lead-calcium alloy, and an oil amount of 16% by mass or less. It is characterized by comprising a restricted separator. Alternatively, in the battery, a positive electrode grid made of a lead-calcium alloy, a negative electrode grid made of a lead-calcium alloy, and
It is made of a separator limited to 0% by mass or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead-acid battery for automobiles, which is provided with a transparent type liquid level specific gravity sensor.

[0002]

2. Description of the Related Art A transparent type liquid level specific gravity sensor (hereinafter referred to as a liquid level sensor) used for a lead storage battery for an automobile is generally mounted so as to penetrate an upper wall of a battery lid. As shown in the figure, the lower end is composed of a rod-shaped transparent body 2 having a float 1 which floats and sinks according to a change in the specific gravity of the electrolytic solution.

One of the functions of a liquid level sensor is to detect the state of charge of a battery based on a change in the specific gravity of an electrolytic solution to determine whether charging is possible. Another function is to check the state of reduction of the electrolytic solution due to electrolysis and evaporation due to overcharging, and to control the liquid level within an appropriate range. Usually, two floats 1 are attached, and the density is changed so that when the specific gravity of the electrolytic solution of the criterion requiring charging is reached, the float 1 is separated into a float and a sink. The above two functions are the rod-shaped transparent body 2
This is achieved by displaying the position of the float 1 on the upper surface 5 of the liquid level sensor by reflection of light through the conical portion 3 provided at the lower portion and the inverted conical reflecting portion 4. The above management by the liquid level sensor is performed by the user.

In order to maintain the function of such a liquid level sensor until the life of the battery, the material of the rod-shaped transparent body 2 must have a good light reflectance so that the reflectance does not decrease until the life of the battery. . As such a material, an acrylic resin or an AS resin is used. However, in recent batteries, the use of a separator mainly containing an electrode-packed polyethylene resin containing oil for the separator has been increasing. Since the oil is contained in the separator in a free state, the temperature of the electrolyte may reach a maximum of 80 ° C. or higher in summer when the separator is incorporated in the battery, and gradually dissolves into the battery. Then, it oxidizes and becomes tar-like, drifts in the electrolytic solution, and adheres to the outer periphery of the rod-shaped transparent body 2 of the liquid level sensor. Therefore, the transparency of the rod-shaped transparent body 2 is remarkably deteriorated, and in the worst case, it adheres to the conical portion and the reflecting portion of the rod-shaped transparent body, and the light reflection is interrupted. May cause disability.

[0005] If the function of the liquid level sensor is impaired, firstly, it becomes difficult to grasp the state of charge. Is not performed, and a discharge state equal to or lower than the engine starting performance is obtained, and the engine cannot be started. Secondly, since the level of the liquid level cannot be confirmed, the opportunity for water replenishment is lost, the upper part of the electrode plate is exposed, and the battery performance is reduced by the exposed part of the electrode plate to reach the engine start impossible region. Even if water was replenished and the liquid level was raised to an appropriate position, the performance could not be recovered, and the battery life was shortened.

From another point of view, even if the user looks at the liquid level sensor to observe the liquid level condition of the liquid level sensor, no indication indicating the position of the float appears on the liquid level sensor. Could have assumed that it had become

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a lead level sensor capable of fully exhibiting the function of a liquid level sensor until the end of battery life. It is to provide a storage battery.

[0008]

In order to solve the above-mentioned problems, a first aspect of the present invention is a lead-acid battery provided with a transparent type liquid surface specific gravity sensor, wherein a positive electrode grid made of a lead-antimony alloy and a lead-acid battery are provided. And a separator having an oil content limited to 16% by mass or less.

According to a second aspect of the present invention, there is provided a lead storage battery provided with a transparent type liquid surface specific gravity sensor, wherein a positive electrode grid made of a lead-calcium alloy, a negative electrode grid made of a lead-calcium alloy, and an oil amount of 20 mass % Or less.

The separator is applied to a separator having fine pores formed by using oil or having improved performance, for example, a separator made of polyethylene resin.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below.

A liquid type lead-acid battery for an automobile is mainly composed of a lead-acid battery called a so-called hybrid battery using a lead-antimony alloy for the positive electrode grid and a lead-calcium alloy for the negative electrode grid, and a lead-calcium-tin battery for the positive electrode grid. System alloy,
A lead storage battery called a so-called calcium battery using a lead-calcium alloy for the negative electrode grid is used.

For both lead-acid batteries provided with a liquid level sensor, a comparison test was performed on the amount of oil adhering to the sensor while changing the amount of oil contained in the separator. The results are shown in Tables 1 and 2.

Table 1 shows the amount of oil contained in the separator between the hybrid battery and the calcium battery,
The battery (75D23 type) is charged with a constant current overcharge method (charge current: 4.5 A, charge time: 21 days, ambient temperature: 75)
Table 2 shows the results of observing the amount of oil adhering to the sensor when charged at a constant voltage (14.8 V, charging time: 2 months, ambient temperature: 75). ° C). Observation results are visual.

The separator was made of polyethylene and used in the form of a bag for packaging an electrode plate. Since the oil is used for producing micropores in the process of manufacturing the polyethylene separator, the amount was changed as shown in Tables 1 and 2 by changing the amount removed in the process of manufacturing the separator.

[0016]

[Table 1]

[0017]

[Table 2]

From Tables 1 and 2, it was found that the larger the amount of oil in the separator, the larger the amount of oil adhering to the sensor. It was also confirmed that the oil adhering to the sensor was turned into tar. It was also found that the amount of adhesion was different if the charging method was different due to the difference between the results in Tables 1 and 2. This is considered to be because the constant current value was constant in the constant current overcharge method shown in Table 1 and the electrolyte temperature during the test was substantially constant, and there was no difference between the two batteries. In the constant voltage charging method shown in Table 2, there is a difference in the overcharge current value during the constant voltage charge, and the hybrid battery is larger than the calcium battery. This indicates that the temperature of the electrolyte rises, and that the oil in the separator easily gushes out.

Next, FIG. 2 shows the results of a life test (JIS light load test) of a hybrid battery having an oil amount of 7.1% by mass, 19.7% by mass, and 21.0% by mass. Note that the terminal voltage is 7.2 V and the oil amount is 21.0% by mass is a conventional product.

From the results shown in FIG. 2, it can be seen that even if the oil amount becomes smaller than that of the conventional product, the life performance hardly changes.

From the above results, considering that the battery is charged at a constant voltage during actual use and that the test shown in Table 2 is a result corresponding to a battery life of 4 years or more, in the hybrid battery, It can be said that the oil amount is required to be 16% by mass or less, and to be 20% by mass or less for a calcium battery in order to maintain the function of the liquid level sensor.

The effects of the oil of the polyethylene resin separator include adjusting the softness of the separator, improving the workability of the electrode plate packaging and the like, and improving the oxidation resistance of the separator. However, since it adheres to the liquid level sensor when the battery is used, it is necessary to limit the amount within a range where the above-mentioned effect is not impaired.

[0023]

As described above, according to the present invention, since the amount of oil adhering to the liquid level sensor can be suppressed, the function of the liquid level sensor can be maintained for the life of the battery. That is, the specific gravity and liquid level of the electrolytic solution can be managed by the liquid level sensor for the life of the battery, and the shortage of charge and the shortage of the electrolytic solution can be eliminated, so that the life of the lead storage battery can be improved.

[Brief description of the drawings]

FIG. 1 is a side view in which a part of a liquid level sensor is cut away.

FIG. 2 is a graph showing a life test result of a battery in which an amount of oil in a separator is changed.

Claims (2)

[Claims] 1. A lead-acid battery provided with a transparent type liquid level specific gravity sensor, wherein a positive electrode grid made of a lead-antimony alloy, a negative electrode grid made of a lead-calcium alloy, and an oil amount are limited to 16% by mass or less. A lead-acid battery comprising a separator. 2. A lead-acid battery provided with a see-through liquid level specific gravity sensor, wherein a positive electrode grid made of a lead-calcium alloy, a negative electrode grid made of a lead-calcium alloy, and an oil amount are limited to 20% by mass or less. A lead-acid battery comprising a separator.