JPS61188852A - Enclosed lead storage battery - Google Patents

Abstract

PURPOSE:To prevent deformation or breakdown of battery by providing an exhaust value to be opened with positive inner pressure lower then 0.5kg/cm<2> and a pinhole or porous material section where the oxygen permeating rate under oxygen partial differential pressure of 0.2kg/cm<2> is lower than 0.02cc/h per 1 Ah. CONSTITUTION:An exhaust valve 1 is made of porous material having gas permeability to perform suction into the battery through said value 1. While exhaustion under overcharge is performed through the tubular section 3 of cover 2 and the exhaust valve 1. the exhaust valve 1 is constructed to be opened when the inner pressure of battery is lower than the positive pressure by 0.5kg/cm<2> while to have the oxygen permeation rate lower than 0.02cc/h per nominal capacity or 1 Ah under the oxygen partial differential pressure of 0.2kg/cm<2>. Consequently, deformation or breakdown of battery is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an improvement in a sealed lead-acid battery using a plastic container.

U Problems to be solved by conventional technology/inventionJ Conventionally,
This type of battery has an exhaust valve 8 with a lid 9 as shown in FIG.
The exhaust valve 8 is attached to a cylindrical portion 10 provided in the exhaust valve 8, and a holding plate 11 prevents the exhaust valve 8 from floating up. This exhaust valve 8 is made of an elastic material, and in order to prevent the battery from being damaged if the battery is overcharged, the internal pressure of the battery should be 0.0 at normal gauge pressure.
It has the function of opening and exhausting when the positive pressure reaches 1 to 0.5 to 9/cni (hereinafter expressed in gauge pressure). However, these conventional exhaust valves cut off oxygen from entering from the outside, and are designed to maintain complete airtightness when the battery becomes under negative pressure. Therefore, when the battery is left unused, the oxygen gas inside the battery is absorbed by the negative electrode, creating a negative pressure.
In particular, if the battery is left full of oxygen, the negative pressure will be close to 1Kq/-, which will cause a large strain on the battery case, deforming the battery case and spoiling its aesthetic appearance. Furthermore, under usage conditions in which charging and leaving the battery are repeated, the internal pressure of the battery fluctuates greatly, so the battery may be damaged due to creep fatigue of the battery case material. Deformation and damage to the battery can be suppressed by making the walls of the battery sufficiently thick, but this is impractical as it increases manufacturing costs and reduces battery energy density.

[Means for Solving the Problems] The present invention solves the above-mentioned drawbacks, uses an accounting plastic container, and provides a closed type container with less deformation and damage.
A7 batteries are provided. That is, in the present invention, a pinhole or a porous body is provided in the battery to slowly draw in outside air, thereby preventing the battery from reaching an excessive 9 pressure. Such pinholes and porous bodies oxidize the electrodes that do not absorb oxygen from outside the battery, reducing the capacity of the battery when left unused. For this reason, for example, in order to suppress the capacity drop to 20% or less after leaving it for three months, it is necessary to
, 2 Kl/c+J's l! F1 inside and outside the battery caused by II partial pressure! The oxygen permeation rate in a pinhole or porous body at a wood partial pressure difference of 0.2 and +1/'aJ is set to a nominal capacity of 1A.
It is necessary to reduce the amount to 0.02 cc per hour or less. Therefore, in the present invention, the pinhole or porous body has a 0.2K
The oxygen permeation rate at the oxygen partial pressure difference of v/a+i is the nominal capacity 1
Reduce it to 0.02 cc/h or less per Ah.

In this way, type 11 lead-acid batteries equipped with pinholes or porous bodies that have an oxygen permeation rate of 0.02 cc/h or less per 1 Ah of nominal capacity do not significantly impair storage performance compared to conventional products. Moreover, it is extremely effective in preventing deformation and damage to the battery due to negative pressure.

[Example] Hereinafter, the sealed lead acid battery of the present invention will be explained with reference to the drawings.

FIG. 1 is a vertical cross-sectional view of a main part of an embodiment of a sealed lead-acid battery according to the present invention, and numeral 1 indicates an exhaust valve made of a gas-permeable porous material. Air is taken into the battery through the exhaust valve 1, while air during overcharging is mainly taken through the contact portion between the cylindrical portion 3 of the lid 2 and the exhaust valve 1. In addition, the exhaust valve 1 is used for positive pressure when the internal pressure of the battery is 0.
．． 5 to 9/cnf or less, and in addition, an oxygen partial pressure difference of 0.2 to 9/- to the nominal capacity ff11
It is configured to have an oxygen permeation rate of 0.02 cc/h or less per Ah. 4 is a holding plate that prevents the exhaust valve 1 from floating up, 5 is a battery case, 6 is an element, and 7 is a terminal.

Next, a sealed lead-acid battery with a nominal capacity of 140Ah and a voltage of 12V and a container wall thickness of 3mm is placed at an equal pressure inside and outside the battery, with Pm
When the cable partial pressure difference is 0.2 q/ad, 0.2 cc/
The length of a simulated battery that was left in a fully charged state for 3 hours was attached with an exhaust valve made of a porous material having an oxygen permeation rate of 0.005 cc/h per nominal volume ff11Ah. Deformation dimension in horizontal direction and 20hR
The following table shows a comparison of the tIi capacitance with a conventional battery of this type equipped with a conventional exhaust valve that is airtight under negative pressure.

As is clear from the above table, the sealed lead-acid battery equipped with the gas-permeable exhaust valve according to the present invention has a capacity of 1'
F! It can be seen that the battery deformation seen in conventional products can be prevented without causing too much deterioration.

In addition, the oxygen permeation rate of the porous material at an oxygen partial pressure difference of 9/cr+l between 0 and 2 is 0.005 cc/per nominal volume ff11Ah.
Even if it is less than 0.005 cc/h, the deformation amount of the battery will be slightly larger than the above test result, but the same effect as the above test result can be obtained.
Between 0.02 cc/h, the battery hardly deforms, and the capacity decrease gradually increases;
If this value is exceeded, the capacity will decrease significantly if left unused for a long time.
It was confirmed through experiments that there was a problem in practical use.

In addition, in the above example, an exhaust valve made of a porous material was used, but the exhaust valve was left as is, and in addition, the W1 cable permeation rate at an oxygen partial pressure difference of 0.2 Kg/crA was 0.02cc/h per nominal capacity ff1lAh
Similar effects can be obtained even if the following porous body portion is provided on the lid or the like. In addition, instead of making the exhaust valve with a porous material, the oxygen permeation rate at an oxygen partial pressure difference of 0.2 K9/- is 0.02 cc/per nominal displacement 1△h.
Similar effects can be obtained even if a pinhole with a diameter of h or less is provided, and even if the pinhole is provided in a portion other than the exhaust valve.

In addition, in the present invention, the opening pressure of the exhaust valve is set to 0.5Kq/- or less to prevent deformation and damage due to excessive negative pressure, as well as to prevent excessive positive pressure during battery overcharging. This is to prevent deformation or damage due to pressure.

[51 Benefits] As mentioned above, the sealed lead-acid battery of the present invention has pinholes and porous bodies that allow gas to pass through, so the battery will not be left under negative pressure for a long period of time, and the battery will It has advantages such as being able to prevent deformation and damage.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part of an embodiment of a sealed lead-acid battery according to the present invention, and FIG. 2 is a vertical cross-sectional view showing the structure of an exhaust valve section of a conventional sealed lead-acid battery of this type. 1... Exhaust valve made of porous material, 2... Lid, 3...
... Cylindrical part, 4... Holding plate, 5... Battery case, 6...
Element, 7...Terminal 2 Diagram

Claims (2)

[Claims] (1) With an exhaust valve that opens when the battery internal pressure is less than 0.5Kg/cm^2 in gauge pressure, 0.2Kg/cm^
A sealed lead-acid battery having a pinhole or porous body portion having an oxygen permeation rate of 0.02 cc/h or less per 1 Ah of nominal capacity at an oxygen partial pressure difference of 2. (2) The exhaust valve has a pinhole with an oxygen permeation rate of 0.02 cc/h or less per 1 Ah of nominal capacity at an oxygen partial pressure difference of 0.2 Kg/cm^2, or is made of a porous material with a similar function. A sealed lead-acid battery according to claim (1) comprising: