JPH0557702B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to an improvement in a so-called negative electrode absorption type sealed lead-acid battery in which oxygen gas generated from a positive electrode is absorbed into a negative electrode to seal the battery. Conventional technology and its challenges Recently, with the spread of cordless devices and small UPS, there has been a strong demand for compact, high-performance sealed lead-acid batteries, especially those with excellent high-rate discharge performance. In order to meet these demands, it is most effective to insert as many thin plates as possible into a battery case of a given volume. However, if the electrode plate is made thinner, the volume change of the active material during charging and discharging will have a greater effect, and the active material will fall off early, especially on the positive electrode plate, resulting in a shortened lifespan. It was difficult to put it into practical use. Means for Solving the Problems The present invention eliminates these drawbacks and provides a sealed lead-acid battery that is small and has excellent high-rate discharge performance.
The gist of this is that an element consisting of a positive electrode plate, a negative electrode plate, and a separator is housed in a monoblock battery case with one long side open so that the electrode plates are parallel to that surface, and the cells are connected. At the same time, each open surface was sealed with a heat-weldable flexible sheet, and the sheet surfaces of these two sets of monoblock battery cases were brought together and the periphery was welded or ultrasonically welded, and then both were connected in series. It is about creating a structure. With this structure, the oxygen gas in the air contained in the battery reacts with the lead on the negative electrode plate and is lost, resulting in a reduced pressure inside the battery, which eventually drops to 0.5 atmospheres. Become. Due to the reduced pressure within the cell, the flexible sheet is concave towards the interior of the battery case, resulting in a very large force pressing on the elements lying parallel to the sheet.
This compression improves the adhesion between the separator and the electrode plates, facilitates liquid diffusion, and greatly improves high rate discharge performance. On the other hand, the main cause of the lifespan of lead-acid batteries due to repeated charging and discharging is the softening and falling off of the positive electrode active material, but it is often effective to prevent this falling off and extend the lifespan by applying high pressure to the element. Are known. However, it is structurally complex, and insertion of elements is extremely difficult, making it difficult to put it into practical use. With the method according to the present invention, there is no pressure applied at all initially, but during use the pressure inside the battery is reduced and the sheet presses the element, making it possible to apply effective pressure in a very simple way. can. However, with this structure where one side of the battery container is sealed with a flexible sheet, when charging with a large current, gas is generated and the inside of the battery becomes pressurized and swells, reducing the pressure on the element. However, by aligning the sheet surfaces of a monoblock battery case and heat welding or ultrasonic welding the surrounding area, it is possible to Since the sheet surface does not directly appear on the surface, strength problems are solved, and the sheets do not come into contact with each other.
Therefore, even if gas is generated due to the large charging current and the inside of the battery is pressurized, the sheets do not swell and press against each other, and the pressure on the element does not decrease. By adopting such a structure, a positive electrode plate with a thickness of 1.0 mm had excellent high rate discharge performance, but was not put into practical use due to its short lifespan. EXAMPLES Next, the present invention will be specifically explained with reference to the drawings. FIG. 1 is a perspective view of essential parts showing one embodiment of the present invention, showing one monobloc battery case, where 1 is a battery case with one long side open, 2 is a negative electrode plate, 3 is a separator, and 4 is a positive electrode. 5 is a negative electrode strap, 6 is a positive electrode strap, 7 is a connection plate, 8 is a safety valve, 9 is a positive electrode terminal, 10 is a negative electrode terminal, and 11 is a sheet welded to the long side of the battery case. Figure 2 shows tank 1 and tank 1'
9 shows the positive terminal, 10' the negative terminal of the battery case 1', and 12 the electrical connection between the two battery cases 1 and 1'. It is something to do. With the above structure, as explained in detail, the element is strongly compressed by the sheet, which improves high rate discharge performance and provides long life performance even with thin electrode plates. In addition, the problem of strength when using a sheet and the swelling of the sheet can be prevented, and a battery that is very small, has excellent high rate discharge performance, and has a long life can be obtained. Table 1 and FIG. 3 show an example of performance comparison between the product of the present invention and a soft product. The conventional product has a positive electrode plate of 3.1 mm, a negative electrode plate of 2.0 mm, and a configuration of two positive electrode plates.
In contrast, the product of the present invention has a positive electrode plate of 1.2 mm, a negative electrode plate of 1.0 mm, and a configuration of four positive electrode plates.
There are 5 negative electrode plates. Table 1 shows the energy density of both products at a rate of 1 minute, and the product of the present invention has an improvement of about 1.8 times compared to the conventional product.

[Table] Figure 3 shows the life performance of both products.Despite the positive electrode plate of the present invention being thinner at 1.2 mm, this structure is superior to that of the conventional product with a positive electrode plate of 3.1 mm. It has been shown to be effective. Effects of the Invention As described above, an element is housed in a monoblock battery case with one long side open so that the electrode plate is parallel to that face, and that face is sealed with a sheet by heat welding, and the monoblock battery case is opened. By bringing the sheet surfaces of the two tanks together and thermally welding or ultrasonically welding their peripheries, a compact sealed lead-acid battery with excellent high-rate discharge performance can be obtained, which is of great industrial value.

[Brief explanation of drawings]

FIGS. 1 and 2 are perspective views of essential parts of an embodiment of a sealed lead-acid battery according to the present invention, and FIG. 3 is a diagram showing a comparison of life performance between the product of the present invention and a conventional product. 1, 1'...Battery container, 2...Negative electrode plate, 3...Separator, 4...Positive electrode plate, 11...Sheet.

Claims (1)

[Claims] 1. In a monoblock battery case with one long side open, an element consisting of a positive electrode plate, a negative electrode plate, and a separator is housed so that the electrode plates are parallel to that side, and the cells are connected, and each open side is These two are sealed with a flexible sheet that can be heat welded.
A sealed lead-acid battery characterized by having a structure in which the sheet surfaces of a set of monoblock battery cases are joined together, the periphery is welded or ultrasonically welded, and the two are further connected in series.