JPS60253150A - Sealed-type lead storage battery - Google Patents

Abstract

PURPOSE:To make a smaller sized storage battery and to reduce the material cost, by forming a V-shaped folding line as well as by making a relief valve consisting of two parallel synthetic resin films or sheets facing to each other without a gap between them, project upwards. CONSTITUTION:An unwelded part consisting of two parallel polyethylene films or sheets 5 facing to each other without a gap is formed as a relief valve 6 in the central part of the battery. It is formed into a slender strip and projected upwards. After the edges of the battery on the right and left sides of the valve are welded, the relief valve is folded at its root by 180 deg. into a V-shape. The relief valve 6 does not restore its original posture, but is bent by 5-10 deg.. In this position, the inner sheet 10 does not contract enough around the folding line 8, but pushes the outer sheet 11 and comes in tight contact with the outer sheet 11. When the valve 6 is open, as it is pushed from the inside by the pressure of the gas, the valve turns to the direction reducing the folding angle. On the other hand, when the pressure inside the battery is decreased, the valve restores its position due to the nature of polyethylene and it becomes closed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in the safety valve portion of a sealed lead-acid battery.

Conventional configuration and problems Sealed lead-acid batteries are widely used as small, portable power sources because the glass fiber mat that serves as a separator retains the electrolyte and does not flow, so the electrolyte does not leak outside during charging. It is widespread. Recently, with the aim of reducing the cost of batteries, various proposals have been made to change the battery container from a mesolock type resin case to a bag-like exterior body made of film-like or 7-layer synthetic resin. This sealed battery is generally
Since the structure is such that the negative electrode plate absorbs the oxygen gas generated on the positive electrode plate at the time of nine discharges, the gas does not normally escape to the outside of the battery. However, when photoelectrically generated with a large current, the oxygen gas absorption capacity of the negative electrode plate is also large, and the amount of oxygen gas generated by the positive electrode plate is large. As a result, the internal pressure of the battery increases, and in the worst case, there is a risk of damage. Therefore, safety valves are provided to prevent this, and various proposals have been made regarding bag-like exterior bodies for this purpose. The first quotient is an example, in which a flat electrode group 4 consisting of a positive electrode plate 1, a negative electrode plate 2, and a separator 3 is attached to two film-like or notebook-like synthetic resin bodies 5 that are acid-resistant and heat-weldable. The synthetic resin body around the electrode plate group 4 is thermally welded and electrically connected by leaving some unwelded parts, and the unwelded parts are made to protrude upward in the form of tongues 6. It was bent into a U shape to serve as a safety valve. However, the valve pressure tends to change depending on the size of the radius of curvature H for bending into a U-shape, parts to bend and fix are required, and the protruding length of the tongue piece is long, which increases material costs. There were problems such as the apparent size of the product.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional problems, and aims to reduce the cost of the safety valve part of a sealed storage battery using a film or sheet-like battery and downsize the battery.

Structure of the Invention The present invention involves sandwiching an electrode plate group consisting of a positive electrode plate, a negative electrode plate, and a separator between film-like or sheet-like synthetic resin bodies that are acid-resistant and heat-weldable, and forming a composite material around the electrode plate group. The resin body is electrically welded by heat welding, leaving some unwelded parts, and the unwelded parts are opened when the internal pressure of the battery is higher than the external pressure, and conversely closed when it is lower, sealing the gap. In a sealed lead-acid battery that is made of a safety valve by making two film-like or sheet-like synthetic resin bodies facing each other in parallel with almost no gap, the safety valve part is made to protrude upward, and one part is made into a V-shape, for example, as a safety valve part. It is folded at the base of the paper and then put back together to create a crease. With this configuration, the battery can be made smaller and the material cost can be reduced, and the battery can be provided at low cost.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 2, a flat electrode plate group 4 composed of one positive electrode plate 1, two negative electrode plates 2, and a separator 3 made of a glass mat is made of a 0.1-thickness plate group 4 that is acid-resistant and heat-weldable. +
2 pieces of 11m polyethylene film or sheet 6
Only the bottom and left and right sides of the periphery of the electrode plate group 4 are heated from the outside at 130° C. for 10 seconds using a hot press to weld 9 the polyethylene to each other and try to conduct electricity. Next, an electrolytic solution consisting of a predetermined dilute sulfuric acid is injected from the unwelded upper part. After injecting the liquid, heat press the upper part again under the same conditions as above to seal the pole pillar 7 and at the same time seal the unwelded part where the two films or sorted polyethylene 6 face each other in parallel with almost no gap. One safety valve 6 is formed in the center. This unwelded part opens when the internal pressure of the battery is higher than the external pressure (when pressurized).
The gas generated from the electrode plate group is released through the gap, and conversely, when the pressure is low (when the pressure is reduced), the valve closes, acting like a safety valve to seal the gap. To explain this safety valve portion 6 in detail, the unwelded portion is formed into an elongated tongue shape as shown in FIG. 2, and is made to protrude upward. After welding the left and right ends as described above, the base of the safety valve 6 is shaped into a V shape.
After bending it 80 degrees, return it to its original position. However, in reality, some material failure occurs in the film or sheet polyethylene itself, and it does not return completely, resulting in a folded state at an angle of about 6 to 10 degrees. In this state, the two polyethylene sheets are
As shown in the figure, at crease 8, the inner side 10 cannot be completely shrunk, and the outer side 11
is pressed, that is, the two polyethylene sheets are in close contact with each other. When the valve is open, both the inner side 1 and the outer side 11 are pushed by gas pressure from inside, so the bending angle is directed in the direction where it becomes smaller.Conversely, when the pressure inside the battery decreases, the polyethylene returns to its parent position due to its own force. Two sheets of polyethylene come into close contact (valve closure) as shown in Figure 1. In this phenomenon, the valve opening pressure changes depending on the ratio of welded and unwelded parts. It has been found that, in general, when the area 9' during welding becomes wider than the unwelded area, the area becomes larger, and when it becomes brittle, it becomes smaller. It was also found that regardless of the length of the unwelded portion, if there is a crease, the valve pressure is determined by the crease, so the valve pressure remains constant. In other words, the length of the unwelded portion can be shortened.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) Since the safety valve part can be made smaller, the battery can be made smaller. (2) The amount of film-like or notebook-like synthetic resin material can be reduced, and the cost of cleaning can be reduced.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a sealed lead-acid battery using a conventional bag-like exterior body, Fig. 2 is a perspective view of a sealed lead-acid battery according to an embodiment of the present invention, and Fig. 3 is a sectional view of the essential parts. It is. 1. Positive electrode plate, 2. Negative electrode plate, 3. Separator, 4
...Electrode plate group, 6..Film-like or sorted synthetic resin, 6. Safety valve, 8..Fold line, 9°9'.
...Welded part. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] An electrode plate group consisting of a positive electrode plate, a negative electrode plate, and a separator is sandwiched between film-like or sheet-like synthetic resin bodies that are acid-resistant and heat-weldable, and some of the synthetic resin bodies around the electrode plate group are not welded. At the same time, the unwelded parts are opened when the internal pressure of the battery is higher than the outside pressure, and conversely closed when it is lower than the outside pressure, so that the gap is sealed by sealing the gap. This is a sealed lead-acid battery with a safety valve made of plastic or sheet-like synthetic resins facing each other in parallel with almost no gaps, and the safety valve part is made to protrude upward and is bent at one point into a V-shape to form a crease. A sealed lead-acid battery characterized by: