JPS6196659A - Separator for sealed lead-acid batteries - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a separator for sealed lead-acid batteries.

Structure of conventional examples and their problems Conventional sealed lead-acid battery separators made of glass fiber as a main component are very difficult to hold electrolyte sufficiently and to quickly diffuse the gas generated from the electrodes. It is common to use thin glass fibers.

Figure 1 shows an example of the configuration of the electrode plate group of a conventional sealed lead-acid battery, where 1 is a separator made of fine glass fiber, and 2 and 3 are positive and negative electrode plates, respectively. .

In the electrode plate group of a conventional sealed lead-acid battery configured as described above, as the number of deep charging and discharging increases, the active material of the positive electrode plate expands, and the sidewalls of the separator expand. It was observed quite frequently that the battery protruded and came into contact with the negative electrode plate, resulting in a short circuit on the side, which caused the life of the battery to be shortened.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a separator for obtaining a sealed lead-acid battery having a long charge/discharge cycle life.

Structure of the Invention In order to achieve the above-mentioned object, the separator for a sealed lead-acid battery of the present invention comprises a felt-like nonwoven fabric mainly made of acid-resistant and highly thermoplastic synthetic resin fibers having a size sufficient to wrap the electrode plate. It is characterized by being folded in two and welding the opposing left and right ends to form a bag shape. Furthermore, the thermoplastic resin fibers account for more than 50 wt% of the whole, and the thickness when pressurized at 20 Ky/dm. Saga, 0.8~3f
It is characterized by being in the range of fll++, and furthermore, the glass fiber with a fiber diameter of 3 μ or less is
It is characterized by containing at a ratio of wt% or less.

Description of examples Next, a specific embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is an example of a group of electrode plates of a sealed lead-acid battery according to the present invention. 4 contains 10 wt% acrylic fibers for strength, 5 wt% acrylic resin as a binder, 70 wt% thin polypropylene fibers as a highly acid-resistant thermoplastic synthetic resin, and the remaining 15 wt% is the fiber diameter. A separator made of felt-like nonwoven fabric, which is glass fiber of 3 μ or less and has a thickness of 1.2 mm when pressurized at 20 Kq/dm, is folded in half into a KU shape large enough to wrap the positive electrode plate 2. It is. Reference numeral 5 denotes a bag-shaped portion formed by ultrasonically welding the opposite left and right end portions.

Voltage 6 ■ Capacity 6.5 Ah using separator A according to the present invention and separator B made of conventional glass fiber
Batteries A and B were manufactured and a cycle life test was conducted.

Figure 3 shows batteries A and B at a voltage of 7.35V at 25°C.
, charged for 6 hours at maximum current 2.6A, current 1.375
This figure shows the results of a cycle life test in which one cycle was a constant resistance discharge equivalent to A until the terminal voltage reached 4.5V. As is clear from Fig. 3, at the 550th cycle, when Battery B manufactured by the conventional method was short-circuited due to protrusion of the active material on the sides and reached the end of its life, Battery A according to the present invention did not experience any capacity deterioration. . Note that if the thermoplastic resin fiber content is 50 wt % or less, ultrasonic welding cannot be performed.

Also, 2oKq/clrn: Thickness when pressurized is 0.8mm
In the case of 3, the electrolyte cannot be held sufficiently, and
If the thickness exceeds 100 mm, the thickness of the electrode plates will decrease significantly when they are separated, and no pressure will be applied to the electrode plate group, resulting in a loss of capacity.

Furthermore, if 10wt% or more of glass fiber with a fiber diameter of 3μ or less is not included, the maximum pore diameter will be too large and there is a high risk that the cathode active material will pass through the separator and short circuit when charging and discharging are repeated. In some cases, welding may be difficult due to the low thermal conductivity of glass. Therefore, the thermoplastic resin fiber is 50 wt% or more, 20 Ky/
d preferably has a thickness of 0.8 to 3N when pressurized and contains glass fibers of 10 wt% or more and 25 wt% or less with a fiber diameter of 3 μm or less.

Effects of the Invention As described above, the present invention folds a felt-like nonwoven fabric mainly made of thermoplastic synthetic resin fibers with high acid resistance into two pieces large enough to wrap around an electrode plate, and then folds the opposite left and right ends together. Because it is welded into a bag-like shape, it prevents short circuits caused by active material protruding, making it possible to supply sealed lead-acid batteries with a longer lifespan than conventional batteries.)

[Brief explanation of drawings]

Figure 1 is a perspective view of the electrode plate group of a conventional sealed lead-acid battery, Figure 2
The figure is a perspective view of a group of electrode plates of a sealed lead-acid battery according to an embodiment of the present invention, and FIG. 3 is a cycle life characteristic diagram of a sealed lead-acid battery according to the present invention and a conventional example. 2...Positive electrode plate, 4...Separator, 5
...Welded part. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (3)

[Claims] (1) A felt-like nonwoven fabric made mainly of highly acid-resistant thermoplastic synthetic resin fibers was folded in half to a size large enough to wrap the electrode plate, and the opposing left and right ends were welded to form a bag. A separator for sealed lead-acid batteries featuring: (2) Thermoplastic resin fiber accounts for 50wt% or more of the total, and the thickness when pressurized at 20Kg/dm^2 is 0.8 to 3mm.
A separator for a sealed lead-acid battery according to claim 1, which falls within the scope of claim 1. (3) 10wt% of the total glass fiber with a fiber diameter of 3μ or less
The separator for a sealed lead-acid battery according to claim 1, which contains the above in an amount of 25 wt% or less.