JPH05325933A - Rolled type sealed alkaline storage battery - Google Patents

Abstract

PURPOSE:To provide a rolled type sealed alkaline storage battery of a long lifetime in which a generation rate of a short circuit at the time of rolling can be sharply reduced and the liquid retaining property of an electrolyte can also be improved. CONSTITUTION:A separator 1 consisting of a woven fabric or a nonwoven fabric, wherein a liquid retaining layer 2 for aiming the liquid retention of a electrolyte and a reinforcement layer 3 for adding mechanical strength are put one over the other in two layers, is used. The woven fabric or nonwoven fabric having two-layer structure is arranged so that the liquid retaining layers 2 are opposite to each other to make the center only in the initial roll-up part of electrode plates, and a positive electrode plate and a negative electrode plate are rolled together to form a rolled type sealed alkaline storage battery.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed alkaline storage battery having a wound structure.

[0002]

2. Description of the Related Art Conventionally, as a separator used in an alkaline storage battery, a woven or non-woven fabric made of fibers such as polyamide synthetic resin, polypropylene, polyvinyl chloride, vinyl chloride / acrylonitrile copolymer and the like has been used. The performance required for the alkaline storage battery separator is (1) leakage to the electrolytic solution, (2) good retention of the electrolytic solution, (3) good ionic conductivity when the electrolytic solution is retained, ( 4) Good gas permeability when holding electrolyte, (5) Chemically and thermally stable to alkaline electrolyte, (6) Electrochemical oxidation-reduction resistance, (7) It is required to have mechanical strength capable of withstanding battery assembly.

In particular, the electrolyte retaining property is most important for a separator of an alkaline storage battery having a closed structure. This is because the electrolytic solution is regulated because it has a closed structure, further migration of the electrolytic solution to the electrode plate occurs with the charge and discharge cycle of the battery, the electrolytic solution in the separator decreases,
This is because there is a problem that liquid dripping will eventually occur.

From the above, the woven or non-woven fabric of polyamide synthetic resin fiber or polyolefin synthetic resin fiber which has been hydrophilized is generally used as the separator. In order to further extend the life of the battery, two or more layers of woven or non-woven fabric composed of ultrafine fibers of polyamide-based synthetic resin or polyolefin-based synthetic resin or modified cross-section fibers in order to increase electrolyte retention Laminated separators have been proposed. For example, in Japanese Patent Laid-Open No. 63-148539, in order to improve the liquid retaining property of an electrolytic solution, a modified cross-section fiber is used, the fiber density is lowered, and the liquid retaining property is further improved. In order to obtain the above, a separator in which two or more layers each having a layer having an increased fiber density are laminated is proposed.

[0005]

However, a wound-type hermetically sealed structure using a separator made of a woven or non-woven fabric having a two-layer structure consisting of a layer intended for retaining an electrolyte and a layer intended for mechanical strength. When an alkaline storage battery was produced, the short-circuit rate was extremely high, and it was difficult to use it in practice.

An object of the present invention is to provide a wound-type sealed alkaline storage battery having a long life, which can greatly reduce the occurrence rate of short circuit at the time of winding and further improve the liquid retaining property of the electrolytic solution. It is in.

[0007]

To explain the constitution of the present invention which achieves the above object, the present invention comprises a liquid-retaining layer for the purpose of retaining an electrolytic solution and a reinforcing layer for adding mechanical strength. In a wound-type sealed alkaline storage battery in which a woven fabric or a non-woven fabric laminated in two layers is used as a separator, and the separator is wound together with an anode plate and a cathode plate, only the winding start portion of the electrode plate has the two A woven or non-woven fabric having a layered structure is arranged and wound so that the liquid retaining layers face each other and become the center.

[0008]

The separator made of woven or non-woven fabric having the two-layer structure of the liquid retaining layer and the reinforcing layer as described above has the liquid retaining layers facing each other only at the winding start portion of the electrode plate. By arranging and winding so that the wound-type sealed alkaline storage battery can be significantly reduced in short-circuit rate and the liquid retaining property of the electrolyte can be improved, the battery life can be improved. It can be greatly improved.

[0009]

EXAMPLE FIG. 1 shows an example of a separator 1 used in a wound type sealed alkaline storage battery of the present invention. As the separator 1, there is used a woven or non-woven fabric in which a liquid retaining layer 2 for retaining an electrolyte and a reinforcing layer 3 for adding mechanical strength are laminated in two layers. In such a separator 1, a woven fabric or a non-woven fabric having a two-layer structure is wound only in the winding start portion of the electrode plate so that the liquid-retaining layers 2 face each other and become the center. It has become.

Next, an example in which the present invention is applied to a nickel-hydrogen battery will be described with reference to FIGS.

As the separator 1, polypropylene synthetic resin fibers having a fiber diameter of 1.2 μm are used, and by defibrating and laminating so that the basis weight is 15 g / m ² , the electrolyte retention rate is 80%.
Liquid retention layer 2 consisting of 0% non-woven fabric layer and fiber diameter 10 μm
Fibers made of the same material are defibrated and laminated with a basis weight of 65 g / m ² ,
Reinforcing layer 3 consisting of a nonwoven fabric layer with a tensile strength of 12 kg / 5 cm width
By stacking two layers of and and heating and pressurizing,
It was formed into a film having a thickness of 0.1 mm, was impregnated with a nonionic surfactant, and was hydrophilized. The liquid retention rate of this separator 1 is 600%, and the tensile strength is 15 kg / 5 cm width. 2 cm from the winding center A of this separator 1 to the left and right
(4 cm in total) was further laminated so that the liquid-retaining layers 2 made of fibers having a fiber diameter of 1.2 μm of the separator 1 were overlapped with each other in the center, and then wound.

This separator 1 and a fiber diameter as a comparative example
80 μm basis weight using 10 μm polypropylene synthetic resin fiber
Using a non-woven fabric separator treated with g / m ² of a surfactant, a nickel anode with nickel hydroxide as the active material and a capacity of 1000 mAh, and a cathode with a capacity of 1500 mAh and an Mm-based hydrogen storage alloy as the active material. After winding so that the outermost periphery becomes the cathode, the obtained electrode group is inserted into a cylindrical battery container, a predetermined amount of 31 wt% potassium hydroxide aqueous solution is injected, and an AA size sealed nickel-hydrogen A battery was produced.

The life test is performed by charging 1 C for 90 minutes and discharging 1 time.
Complete charging / discharging was carried out by discharging at C to a final voltage of 1V.

The high rate discharge test is carried out at a charge of 0.1 C for 900 minutes,
Discharge is 0.2 C, 1 C, 3 C, and final voltage is 1
Discharged to V.

When the occurrence rate of short circuit of the battery after winding was investigated, the battery using the conventional separator was about 0.8%, whereas the battery using the separator of the present invention was 1.
It was almost equal to 0% or less (the occurrence rate of short circuit without the present invention was about 80%).

FIG. 2 shows the life test results of the battery using the conventional separator and the battery using the separator of the present invention. The battery using the conventional separator had a capacity drop due to liquid dripping from over 300 cycles. On the other hand, the battery using the separator of the present invention,
The capacity did not decrease even after 500 cycles.

FIG. 3 shows the results of the high rate discharge test of the battery using the conventional separator and the battery using the separator of the present invention. In contrast to the battery using the conventional separator, the battery using the separator of the present invention has improved characteristics at high rate discharge.

The tensile strength shown here is obtained from the maximum strength when it is broken by a tensile tester, and the electrolytic solution holding amount is 10 minutes after immersing the sample in a 31 wt% potassium hydroxide aqueous solution for 30 minutes. It was determined by dividing the weight after hanging by the weight before the test.

[0019]

As described above, in the wound-type sealed alkaline storage battery according to the present invention, the woven or non-woven fabric having the two-layer structure of the liquid retaining layer and the reinforcing layer is provided only on the winding start portion of the electrode plate. Since the liquid-retaining layers face each other and are wound so as to be centered, the short-circuit rate when producing a wound-type sealed alkaline storage battery is significantly reduced, and the electrolyte solution is It is possible to improve the liquid retaining property of the battery and it is possible to significantly improve the battery life.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an embodiment of a separator used in a wound-type sealed alkaline storage battery according to the present invention.

FIG. 2 is a comparative diagram showing the relationship between the number of times charging and discharging and the discharge capacity of the present invention and a conventional nickel-hydrogen battery.

FIG. 3 is a comparison diagram of high rate discharge characteristics of the present invention and a conventional nickel-hydrogen battery.

[Explanation of symbols]

 1 Separator 2 Liquid retaining layer 3 Reinforcing layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Ishii 2-1, 1-1 Nishishinjuku, Shinjuku-ku, Tokyo Shin-Kindo Electric Co., Ltd.

Claims (1)

[Claims] 1. A woven or non-woven fabric comprising two layers of a liquid-retaining layer intended to retain an electrolyte and a reinforcing layer for adding mechanical strength is used as a separator, and the separator is an anode plate. In a wound-type sealed alkaline storage battery that is wound together with a cathode plate, a woven or non-woven fabric having the two-layer structure only in the winding start portion of the electrode plate, the liquid retaining layers are facing each other. A wound-type sealed alkaline storage battery, wherein the wound-type alkaline storage battery is arranged so as to be centered and wound.