JPS59186251A - Enclosed type lead storage battery - Google Patents

Abstract

PURPOSE:To provide an enclosed type lead storage battery with an safety valve being always stable in its opening and shutting performance throughout its operating period, by disposing a porous member impregnated with oil at the periphery or lower part of a rubber valve for always supplying the oil to the rubber valve for preventing a change in the operating pressure of the rubber valve. CONSTITUTION:A porous member 2 impregnated with oil is disposed on the interior, exterior or at the lower part of the safety valve 1 in contact therewith. The porous member, for example, is disposed on the periphery of the rubber valve 1 (A) or at the lower part of the rubber valve 1 (B); in another arrangement, the porous member 2 impregnated with oil is disposed at the lower part of the rubber valve 1 and a threshold 4 is provided surrounding the porous member for preventing the oil from flowing out (C) or the porous member 2 is enclosed between the rubber valve 1 and the valve seat 3 so that the oil is prevented from evaporating (D).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to extending the life of a safety valve for a sealed lead-acid battery.

Sealed lead-acid batteries include those that utilize a catalyst plug and those that use a cathode absorption type that uses a negative electrode to absorb oxygen generated during charging, and the present invention particularly relates to the latter.

This type of battery has the following characteristics: it does not require water replenishment during use, it does not leak, it can be used in any position (up, down, left or right), and there is no need to charge it evenly from time to time. Therefore, users do not need to pay special attention to or maintain batteries, so they have recently come to be used in a variety of fields. For example, Portaple VT
Its uses are wide-ranging, including TVs, emergency power sources, and portable power sources.

As mentioned above, the battery is sealed by absorbing oxygen generated during charging at the negative electrode. Therefore, the pressure inside the battery is reduced by a pressure corresponding to the oxygen partial pressure. In addition, in this battery, the purpose is to prevent oxygen from the atmosphere from entering the battery, and to release the pressure to the outside when an abnormality occurs and the internal pressure of the battery becomes extremely high. A safety valve is provided. In such batteries, a rubber material is usually used for the safety valve. Therefore, the battery is constructed on the premise that a safety valve (hereinafter referred to as a rubber valve) using a rubber material opens at a predetermined pressure and closes at a predetermined pressure. Therefore, if the rubber valve deteriorates, it will have a decisive negative effect on the battery. For example, if a rubber valve adheres to the valve seat on which it is fitted, the valve opening pressure will increase and the battery will swell, and if the valve closing pressure decreases, oxygen from the atmosphere will enter the battery. This will cause the battery capacity to decrease.

The present invention provides a sealed lead-acid battery equipped with a safety valve that suppresses changes in the operating pressure of the rubber valve as described above and maintains stable opening and closing pressure throughout the period of use. The gist of this method is to arrange a porous body impregnated with oil around or below the rubber valve, thereby constantly replenishing the rubber valve with oil.

Hereinafter, the present invention will be specifically explained using the drawings.

Figure 1 shows an example of the arrangement of a porous body impregnated with oil around a rubber valve according to the present invention. (B) is an example in which a porous body 2 impregnated with oil is placed at the bottom of a rubber valve 1, and (C) is an example in which a porous body 2 impregnated with oil is placed at the bottom of a rubber valve 1, and An example in which a weir 4 is provided around the valve to prevent oil from flowing out, and (D) is a porous body impregnated with oil between the rubber valve 1 and the valve seat 3 to prevent oil from evaporating. This is an example in which the porous body 2 that impregnates and retains oil can be made of any porous body having open cells.Polyethylene foam, polypropylene foam, polyurethane foam,
Various materials such as alumina sintered body or copper sintered body can be used.

Next, as shown in FIG.
An H-12V sealed lead-acid battery and a conventional sealed lead-acid battery with the same capacity without a porous body impregnated with oil were made, and when used with 2.25 V/cell float charging. Figure 2 shows the change over time during the test period as a percentage of the initial capacity. The battery according to the invention is 1
The capacity tended to decrease after 0 years, but this was because the lead alloy lattice on the positive electrode plate of the battery had become frayed due to corrosion and no longer functioned as an electrode plate, and the operating pressure of the rubber valve was still normal. there were. The operating pressure of this rubber valve was normal because the oil impregnated and held in the porous body was gradually replenished into the fine pores of the rubber material, protecting the rubber material from oxidative deterioration caused by oxygen in the atmosphere. The deterioration of the rubber material is prevented, or the presence of a thin layer of oil on the surface of the rubber material prevents the sulfuric acid mist generated during charging from attacking the rubber material, thereby preventing the deterioration of the rubber material. This is thought to be due to the following. In contrast, conventional batteries lose their capacity significantly after about three to four years. This was because the rubber valve had deteriorated and no longer had the ability to close properly, allowing oxygen from the atmosphere to enter the battery, causing the negative electrode to turn into lead sulfate and reducing its capacity.

In this way, the stabilization of the rubber valve is closely related to the longevity of the battery, and no matter how high-quality the battery's positive and negative electrode plates are, if the rubber valve is defective, the problem will occur. The capacity of the battery decreases immediately.

As described above, the present invention extends the life of a sealed lead-acid battery and stabilizes it, which is its industrial value.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a main part showing an embodiment of the safety valve part of a sealed lead-acid battery according to the present invention, and Fig. 2 is a characteristic diagram showing changes in capacity over time of a sealed lead-acid battery according to the present invention and a conventional battery of this type. be. 1...Rubber valve, 2...Porous body impregnated with oil, 3...Valve seat

Claims (1)

[Claims] A sealed lead-acid battery characterized by having a porous body impregnated with oil placed in contact with the inside, outside, or bottom of a safety valve.