JPH0927350A - Sealed lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly hold a voltage setting value in constant voltage charging by forming a depressed part for housing a temperature sensor in a lid of a battery container in a sealed lead-acid battery, and bringing the depressed part into contact with a separator. SOLUTION: In a sealed lead-acid battery, a cylindrical depressed part with a bottom 7 is formed in a portion locating in a third cell from a positive terminal, between an exhausting port 6 and a pole through hole 20 in a lid 5 of a battery container 4. The depressed part 7 has a space capable of housing a temperature sensor 9, the bottom 30 of the depressed part 7 comes in contact with a separator 3, and the temperature sensor 9 is fixed to the inside bottom 40 of the depressed part 7 with an adhesive 10. Since response ability in electrode plate temperature detection is enhanced and electrode temperature is accurately detected, voltage setting value in constant voltage charging is properly held.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed lead-acid battery.

[0002]

2. Description of the Related Art In recent years, a constant current-constant voltage system has been generally used as a charging system for a sealed lead-acid battery used for cycle applications such as electric vehicles and small consumer products.

This method limits the maximum charging current in constant voltage charging. At first, the battery is charged with a substantially constant and comparatively large current, and when the gas generation voltage is reached, the battery is charged with the same voltage until the end. To do.

This method is characterized in that the current at the end of charging is small, so that the amount of electrolytic solution decreases little and the temperature rise of the battery is small.

The set value of the constant voltage is usually considered on the basis of the gas generation voltage. However, since the charging IV characteristic of the battery has temperature dependency, for example, -5 mV per 2 V of the battery with respect to the set value. It is determined by the method of multiplying the temperature coefficient of / ° C. As an example, at 30 ° C., a set value of constant voltage of 2.45 V is multiplied by a temperature coefficient of −5 mV / ° C., and at 50 ° C., 2.
The charger is designed to have a set value of 35V.

On the other hand, since the battery temperature varies depending on the usage method, external environment, etc., a temperature sensor is mounted on the surface of the battery, the set value of the constant voltage is determined according to the temperature detected at the start of charging, and the battery is charged until the end. How to do it, or while charging,
A method of constantly monitoring the battery temperature and changing the setting of the constant voltage value each time is used.

[0007]

However, when the temperature is detected on the surface of the battery, the responsiveness to the temperature change of the electrode plate portion, which is the cause of the fluctuation, is not good, so the set value of the constant voltage deviates from the optimum value. The battery performance may deteriorate due to insufficient charging or overcharging.

On the other hand, the method of mounting the temperature sensor inside the battery so as to be in contact with the electrode plate portion solves the above problem, but has a drawback that it is very difficult to secure the airtightness.

[0009]

SUMMARY OF THE INVENTION Therefore, the present invention has been made to solve the above-mentioned problems, and a recessed portion for disposing a temperature sensor is formed in the battery case or the lid, and the recessed portion is formed. The part is provided so as to contact the electrode plate or the separator.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a sealed lead-acid battery according to the present invention will be described in detail with reference to Examples.

FIG. 1 is a schematic sectional view showing an embodiment of a sealed lead acid battery according to the present invention.

In the figure, 1 is a positive electrode plate, 2 is a negative electrode plate,
3 is a glass separator inserted between the positive electrode plate and the negative electrode plate, 4 is a battery case, 5 is a lid, 6 is an exhaust port, 8 is an exhaust valve mounted above the exhaust port 6, 11 is an exhaust valve cover, 9 is a temperature sensor.

Reference numeral 7 is a recess formed in the lid 5, and in this embodiment, between the exhaust port 6 and the intermediate through hole 20,
It is formed in the part located in the third cell from the positive electrode terminal,
It is formed in a bottomed cylindrical shape. Reference numeral 30 denotes a bottom of the recess 7 inside the battery case, and 40 denotes an inner bottom of the recess 7.

The depression 7 is formed so that the bottom 30 of the depression 7 is in contact with the separator when the lid 5 and the battery case 4 are welded together.

The shape of the depression 7 is sufficient if it has a space for accommodating the temperature sensor 9 and the bottom portion 30 or another portion of the depression 7 is in contact with the separator or the electrode plate. Although it is formed on the lid here, it may be formed on the battery case.

The temperature sensor 9 is fixed by an adhesive 10 so as to come into contact with the inner bottom portion 40 of the depression 7.
The fixing method is not limited to the adhesive, and may be fixed with resin or putty, and any fixing method may be used.

With such a structure, a 12 V sealed lead acid battery for cycle service (3 hour rate rated capacity is 60 Ah)
Was manufactured and a life test was performed. For comparison, a conventional product having a temperature sensor mounted on the top surface of the lid was also tested under the same conditions. (The mounting position of the sensor is the depression 7 according to the present invention.
It is the same position as. ) The life test conditions are as follows: discharge at 20 A for 144 minutes (DOD80
%), A constant current-constant voltage system was used, in which the battery was charged with a constant current of 15 A in the initial stage, and after the battery voltage reached a set value, charging was performed with a constant voltage.

The constant voltage setting value is 1 when the battery temperature is 30 ° C.
Based on 4.7 V, the cell temperature coefficient of −5 mV / ° C. was multiplied to obtain a set value of 14.1 V at 50 ° C. Then, during charging, a method of constantly monitoring the battery temperature and changing the set value of the constant voltage each time was used.

The charging time is 8 hours, and the test is 30 hours.
It was carried out in the gas phase at ℃.

In addition, 20 A discharge (final voltage 9.9 V) and battery weight measurement were carried out every 50 times of the above charge / discharge cycles to determine the 3 hR discharge capacity and the reduction amount (reduction amount) of the electrolytic solution.

The test results are shown in FIG.

From the figure, the product of the present invention has a capacity of about 90% of the rated capacity at the end of 400 cycles, whereas the conventional product reaches 80% of the rated capacity after the completion of 300 cycles, and has a long life. Has been reached.

Comparing the liquid reduction amounts, the liquid reduction amount of the conventional product is about 1.5 times that of the product of the present invention.

The large amount of liquid reduction of the conventional product is that the temperature of the upper surface of the lid is detected to be lower than the temperature of the electrode plate portion during charging, so that the battery is charged at a constant voltage set value higher than the optimum value. This is probably because the amount of electrolysis of water in the electrolytic solution increased.

Further, in the investigation after the end of the life test, it was found that the conventional positive electrode active material was more mud-like than the product of the present invention. This is considered to be deterioration due to the high concentration of the electrolytic solution.

That is, in the sealed lead-acid battery according to the present invention, the recess for placing the temperature sensor is formed in the battery case or the lid, and the recess is provided so as to contact the electrode plate or the separator. Since the temperature sensor can directly sense the temperature of the electrode plate, it does not detect a temperature lower than the actual electrode plate temperature as in the conventional case.

[0027]

In the sealed lead-acid battery of the present invention, the recess for placing the temperature sensor is formed in the battery case or the lid, and the recess is provided so as to contact the electrode plate or the separator. It is characterized by being

As a result, the responsiveness at the time of detecting the electrode plate temperature is excellent and the electrode plate temperature can be accurately sensed, so that the voltage setting value at the time of constant voltage charging can be maintained at an appropriate value.

Therefore, since abnormal liquid reduction does not occur, the life of the battery can be improved.

Further, unlike the method of mounting the temperature sensor inside the battery, complicated work for ensuring airtightness is not required.

The industrial value of the present invention is very great.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a battery according to the present invention.

FIG. 2 is a diagram showing a life test result of a battery according to the present invention and a conventional battery.

[Explanation of symbols]

 1 Positive Plate 2 Negative Plate 3 Glass Separator 4 Battery Case 5 Lid 6 Exhaust Port 7 Cavity 8 Exhaust Valve 9 Temperature Sensor 10 Adhesive 11 Exhaust Valve Cover 20 Pole Through Hole

Claims (1)

[Claims] 1. A sealed lead acid battery, characterized in that a recess for arranging a temperature sensor is formed in a battery case or a lid, and the recess is provided so as to come into contact with an electrode plate or a separator. .