JPH041465B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvement of lead-acid batteries, and its purpose is to improve the electrolyte concentration inside the battery, which occurs in lead-acid batteries used in a charging method that does not generate sufficient gas. The aim is to extend the life of lead-acid batteries and improve charging efficiency by eliminating unevenness.

In general, lead-acid batteries for cycle service are charged using a voltage control method because the amount of electricity discharged varies from day to day and the amount of electricity to be charged is not fixed.

In this case, if the set voltage is too high, the amount of overcharged electricity will increase, energy loss will increase, and at the same time, battery deterioration will be accelerated. On the other hand, if the set voltage is too low, the battery will not generate enough gas and the electrolyte will not be stirred, resulting in a low electrolyte concentration at the top of the battery and a high concentration at the bottom. Such non-uniform electrolytic solution concentration, so-called electrolytic solution stratification, also reduces charging efficiency and leads to a reduction in discharge capacity. Furthermore, if charging and discharging are repeated under such conditions, the stratification of the electrolyte will increase,
This will cause early capacity reduction of the battery.

In addition, the amount of battery charge is significantly affected by the ambient temperature at which it is used, and even if the voltage allows proper charging in the temperature range of 20 to 40 degrees Celsius, the amount of gas generated decreases when used in cold regions or in winter. As a result, stratification of the electrolyte occurs, leading to a decrease in battery capacity.

A known method for preventing stratification of the electrolyte without significantly overcharging the battery is to stir the electrolyte by blowing air in from the outside. However, this method requires (1) an air blower to the battery; (2) All batteries must be connected with air pipes. (3) There are drawbacks such as the need for energy to operate the blower device.

The present invention utilizes the increase in internal pressure of the battery due to a small amount of gas generated within the battery, and is characterized by attaching to the lead-acid battery a device that efficiently stirs the electrolyte using this small amount of gas.

Hereinafter, the present invention will be specifically explained using the drawings. FIG. 1 shows the structure of an embodiment of a lead-acid battery equipped with an electrolyte stirring device according to the present invention, in which 1 is a battery case, 2 is a group of electrode plates, and 3 is an electrolyte. 4 is a cylindrical container constituting a liquid stirring device, which has four openings, namely, a liquid inlet 5, a liquid outlet 6, a gas inlet 7,
It has a gas outlet 8 , and a convex portion 9 is provided above the gas inlet 7 . The liquid inlet 5 is disposed in the electrolyte, preferably near the bottom of the battery. The liquid outlet 6 is located above the electrolytic solution, or near it if it is above the electrolytic solution surface. The gas inlet 7 is located above the liquid outlet 6 on the electrolyte level. The gas outlet 8 is arranged at the upper part of the cylindrical container 4 and above the gas inlet 7.

In this embodiment, the gas outlet 8 is placed outside the battery case 1, but it may be placed inside the battery. However, the gas outlet 8 is open to the atmosphere outside the battery, and a piston 11 is placed above it.
It is sufficient if there is a space equal to the thickness of . Two pistons, an upper piston 11 and a lower piston 12, connected by an axial rod 10 are installed in this cylindrical container 4. Piston 11 at the top of the shaft rod 10
can move from the top of the gas inlet 7 to the top of the gas outlet 8. The piston 12 at the bottom of the shaft 10 has a liquid inflow valve 13, and the piston 12
It opens only when the electrolyte in the lower part of the piston 12 flows into the upper part of the piston 12. This lower piston 12 is located within the cylindrical container 4 from the liquid inlet 5 to the liquid outlet 6, and is attached to the shaft rod 10 so that it can move within the vertical distance that the upper piston 11 can move. The length is longer than the distance from the upper part of the gas outlet 8 to the lower part of the liquid outlet 6 and shorter than the distance from the convex part 9 to the liquid inlet 5. These pistons are constructed so that there is no leakage between them and the inner wall of the container 4, and can move smoothly.

Next, the operating principle of this embodiment of the present invention will be explained. It is now assumed that the internal pressure of the battery is atmospheric pressure and the piston 11 inside the cylindrical container 4 is in contact with the upper part of the convex portion 9. At this time, the electrolytic solution level inside the cylindrical container 4 is at the same height as the electrolytic solution level outside the cylindrical container 4. During charging, the internal pressure of the battery gradually increases due to the generated gas, and the gas inlet 7 provided in the container 4
Battery internal pressure is applied to the lower part of the piston 11 inside.
Since the gas outlet 8 provided at the top of the container 4 is open to the atmosphere at the top of the piston 11,
This means that atmospheric pressure is applied. The piston 11 moves up inside the container 4 as the internal pressure of the battery increases. At this time, the piston 12 at the bottom of the shaft 10 connected by the shaft 10 moves up in conjunction with the piston 11.
At this time, the electrolyte in the container 4 is lifted by the piston 12 and flows out from the liquid outlet 6 to the upper part of the electrolyte. When the battery internal pressure further increases and the piston 11 rises to the upper part of the gas outlet 8, gas flows out from the gas outlet 8 into the atmosphere, and the electric escape internal pressure decreases.
When the internal pressure of the battery decreases, the piston 11 lowers inside the container 4 due to its own weight and comes into contact with the protrusion 9 and stops. At this time, the lower piston 12 opens the liquid inflow valve 13 and lowers the inside of the container 4 while allowing the electrolyte at the lower part of the piston 12 to flow into the upper part of the piston 12.
1 comes into contact with the convex portion 9 and stops at the same time. In this way, the electrolyte in the lower part of the battery is transported to the upper part of the battery.
Furthermore, the internal pressure of the battery increases due to charging, and the series of operations described above are repeated. By repeating this operation, the highly concentrated electrolyte at the bottom of the battery is efficiently transported to the top of the battery, and stratification of the electrolyte is eliminated.

Next, one embodiment of the present invention will be described in detail. capacity
330Ah (8hR) approximately 50cm high lead-acid battery for electric cars,
Attach the electrolyte stirring device shown in Figure 1 (Battery symbol A), set the environmental temperature to 5°C, perform a charge/discharge cycle of fully discharging at 8hR current, and charging at a constant voltage of 2.40V for 5 hours. I did it. For comparison, a conventional battery without a liquid stirring device (symbol B) was used, and a plastic pipe was inserted into the battery and air was pumped in from the outside at a rate of 400 cc/min using a compressor to stir the liquid during charging. A similar charge/discharge cycle was performed on the battery (symbol C). The charge amount of these batteries during the cycle was within the range of 103 to 105% of the previous discharge amount. FIG. 2 shows the changes in the specific gravity of the electrolyte at the top of the battery before discharge (after charging) and the discharge time of these batteries during the charge/discharge cycle.

Conventional battery B without a liquid stirring device
The electrolyte gradually became stratified, and the specific gravity of the electrolyte at the top of the battery decreased to 1.11 at the 25th cycle. The discharge time also became shorter as the stratification of the electrolyte increased, and at the 25th cycle, the capacity was about 1/3 of the initial capacity. In contrast, in lead-acid battery A equipped with the liquid stirring device according to the present invention, even after repeated charging and discharging 50 times, the electrolyte specific gravity at the top of the battery decreased by about 0.01, and the capacity decreased by 2 to 3%. .

This value was almost the same as when the liquid was stirred by supplying air from outside.

As detailed above, according to the present invention, by simply installing a simple liquid stirring device, the electrolyte can be efficiently stirred by a small amount of gas generated from the lead-acid battery, thereby reducing the concentration of the electrolyte in the battery. It is possible to prevent a decrease in capacity due to uniformity, so-called stratification. Furthermore, the present invention does not require an external blower device or energy to operate it, and also eliminates the need for piping for blowing air to each battery, which has great industrial value.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view showing the structure of an embodiment of a lead-acid battery equipped with an electrolyte stirring device according to the present invention, and Fig. 2 shows the electrolytic specific gravity and discharge time of the inventive product and the conventional product during charge/discharge cycles. It is a characteristic diagram showing the transition. 1... Battery container, 2... Plate group, 3... Electrolyte, 4
... Cylindrical container, 5... Liquid inlet, 6... Liquid outlet, 7... Gas inlet, 8... Gas outlet, 9...
...Protrusion, 10... Axis rod, 11... Piston, 12
...Piston, 13...Liquid inflow valve.

Claims (1)

[Claims] 1. Liquid inlet near the bottom of the battery, liquid outlet near the electrolyte surface, gas inlet in the battery above the electrolyte surface,
It has a cylindrical container with a gas outlet opening to the atmosphere at the top, and a shaft rod connecting two pistons vertically, with the upper piston moving from the top of the gas inlet to the top of the gas outlet. The lower piston has a valve that allows the electrolyte to pass only from the bottom to the top of the lower piston, and is movable from the upper part of the liquid inlet to the lower part of the liquid outlet, and has a cylindrical shape. A lead-acid battery equipped with an electrolyte stirring device characterized in that a container is arranged between a group of electrode plates and an inner wall of a battery case.