JPH076621Y2 - Sealed storage battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an improvement of an exhaust valve of a sealed storage battery.

Conventional technology and its problems In a general sealed storage battery, oxygen gas generated from the positive electrode at the end of charging is chemically or electrochemically reacted with the negative electrode active material to be absorbed and sealed.

A storage battery using a metal cylindrical can can be designed by increasing the internal pressure of the battery due to gas generation to 10 to 20 atm. However, in a prismatic battery using a plastic battery case, the internal pressure must be designed low because the battery container is likely to swell. Generally, this design pressure is less than 1 atm and around 0.5 atm. The exhaust valve prevents the expansion of the battery case by activating the exhaust valve and discharging the gas to the outside when the design pressure for operating the exhaust valve is reached without catching up with the oxygen gas. The exhaust valve not only discharges gas, but also serves to prevent air from entering the storage battery from the outside. Therefore, various studies have been made on the structure or shape of the exhaust valve. Conventional exhaust valves have drawbacks such as large variations in operating pressure, resulting in swelling of the battery case, or shortening of battery life due to intrusion of air from the outside into the battery.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems,
It is an object of the present invention to provide a sealed storage battery that has a small variation in the exhaust valve operating pressure and operates stably so that the battery case does not swell and has a long life.

Structure of the Invention In order to achieve the above object, a sealed storage battery is provided with an exhaust valve having an M-shaped cross-section with an upper central portion previously recessed.

Embodiment Hereinafter, details of the present invention will be described with reference to an embodiment.

FIG. 1 is an enlarged cross-sectional view of an essential part of an exhaust valve attached to a sealed storage battery showing an embodiment of the present invention, and FIG. 2 is a view showing a conventional exhaust valve attached.

Here, 1 is an exhaust valve, 2 is a holding plate, 3 is an exhaust hole portion, and 4 is a plastic lid.

The exhaust valve 1 used in the present invention is made of a rubber-like elastic body such as neoprene rubber or isoprene rubber, has a hollow central portion on the upper surface, and its cross section is M-shaped as shown in FIG. The exhaust valve 1 is attached to the exhaust hole 3 of the storage battery.
The outer diameter of the exhaust hole portion 3 and the inner diameter of the tubular portion of the exhaust valve 1 have the same dimension. Next, the holding plate 2 holds the exhaust valve 1 against the upper end surface of the exhaust hole 3.

Ten cells of the conventional sealed storage battery using the sealed storage battery of the present invention and the conventional exhaust valve with a flat upper part (Fig. 2) were prototyped, and the operating pressure of the rubber valve was measured. Immediately after trial production of the battery and after storage at a temperature of 60 ° C. for 20 days, the valve opening pressure at which the exhaust valve operates due to an increase in internal pressure and the equilibrium pressure after that were measured. Both the exhaust valve used in the present invention and the conventional exhaust valve are made of the same neoprene rubber, and have the same thickness and size.

The results of the comparative test are shown in Table 1.

From the results shown in Table 1, the battery of the present invention has a valve opening pressure and an equilibrium pressure that are similar to each other and has a small variation. On the other hand, the conventional product has a large difference between the valve opening pressure and the equilibrium pressure, and the variation is also large.

Therefore, the battery swelling does not occur and the battery life is not shortened by the invasion of air from the outside into the battery.

The advantage of the exhaust valve used in the present invention is that the M-shaped top is pushed up by the rise of the internal pressure, and the outer periphery of the upper end is pushed outward, thereby creating a gap at the peripheral edge of the upper end of the exhaust hole, Is easily released, and the valve opening pressure and the equilibrium pressure are approximate values.

In particular, after storage, in the conventional product, the exhaust valve closely adheres to the exhaust hole and the valve opening pressure becomes very high, but in the present invention, the valve opening pressure is kept low by expanding the outer circumference of the upper end.

Effect of the Invention As described above, the present invention has a small variation in the exhaust valve operating pressure and can operate stably, so that it is possible to provide a sealed storage battery that does not swell and has a long life. The target value is great.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of an essential part of an exhaust valve attached to a sealed storage battery showing an embodiment of the present invention, and FIG. 2 is a view showing a conventional exhaust valve attached. 1 ... Exhaust valve, 2 ... Holding plate 3 ... Exhaust hole, 4 ... Lid

Claims (1)

[Scope of utility model registration request] 1. A sealed type storage battery, characterized in that an exhaust valve having an M-shaped cross-section with a central recessed upper surface is attached to an exhaust hole of a lid.