JPH05283056A - Sealed alkaline storage battery - Google Patents

Abstract

PURPOSE:To improve the degree of acceptance of charging at high temperature and provide large discharge capacity by changing a negative electrode lead and a terminal material. CONSTITUTION:A sealed alkaline storage battery is constituted of a negative electrode 2 capable of performing charge and discharge processes, and a positive electrode 3 comprising nickel hydroxide. In addition, at least one of the lead 4 and terminal 5 of the negative electrode 2 for the sealed alkaline storage battery using an alkaline water solution as an electrolyte is made of copper. As copper having good heat conduction is used for the lead 4 of the negative electrode 2 and the terminal 5 as mentioned, heat generated on the negative electrode 2 can be quickly discharged outside the 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, and more particularly to a sealed alkaline storage battery using nickel hydroxide as a positive electrode active material of a large battery having improved charging characteristics.

[0002]

2. Description of the Related Art In recent years, sealed nickel-hydrogen storage batteries, nickel-cadmium storage batteries, and nickel-zinc storage batteries using nickel hydroxide for the positive electrode, hydrogen storage alloy for the negative electrode, and alkaline aqueous solution for the electrolyte have been attracting attention because they can achieve high energy density. ing. For the positive and negative electrode leads and terminals of these batteries,
Nickel, which has good electric conductivity, has been used.

The charging mechanism at the positive electrode of this battery is several (1).
Proceed like. The discharge reaction is the opposite. e ^- is an electron.

[0004]

[Equation 1]

However, during charging, not only the above reaction but also the side reaction shown in the equation (2) occurs.

[0006]

[Equation 2]

Therefore, for the reaction of the number (2) at the positive electrode, in the sealed nickel-metal hydride storage battery, a method of guiding the generated oxygen gas to the negative electrode and making it water as shown in the number (3) is used.

[0008]

[Equation 3]

[0009] The seal is maintained. Here, M represents a hydrogen storage alloy, and MH represents a hydrogen storage alloy that has stored hydrogen.

[0010]

The reaction represented by the number (2) occurs more predominantly as the number (1), which is the charging reaction of the positive electrode, as the temperature increases, and at a high temperature, for example, 45 ° C., the positive electrode is charged. Even if charged with 150% of the capacity, the positive electrode is charged with only 50%.

Since the sealed alkaline storage battery is sealed by utilizing the reaction of the formula (3), the reaction heat of the formula (3) is generated in the battery and the battery temperature rises. In the case of a battery of about 10 Ah, the temperature rise of the battery is relatively small due to the heat radiation effect from the battery case and the nickel terminal when charged for 10 hours. However, in a battery of 25 Ah or more, heat generation starts to become more remarkable than heat radiation. Even with a 10 Ah battery, heat generation is remarkable at high rate charging.

Due to this heat generation, the battery temperature increased, the charge acceptance of the positive electrode decreased, and a sufficient discharge capacity could not be obtained.

An object of the present invention is to provide a sealed alkaline storage battery in which charge acceptance at a high temperature is improved and a large discharge capacity is obtained by changing the material of the negative electrode lead or terminal.

[0014]

To achieve this object, the sealed alkaline storage battery of the present invention comprises a chargeable / dischargeable negative electrode,
At least one of a positive electrode made of nickel hydroxide and a lead and a terminal of a negative electrode of a sealed alkaline storage battery using an alkaline aqueous solution as an electrolyte is made of copper.

[0015]

In the sealed alkaline storage battery, oxygen generated from the positive electrode is returned to water by the reaction of the number (3). The temperature rises due to the heat of reaction at this time. As is clear from the equation (3), the place where the reaction occurs is on the negative electrode. Therefore, heat is also generated on the negative electrode and transmitted to the positive electrode through the electrolytic solution and the separator.
The transferred heat raises the temperature of the positive electrode and further facilitates oxygen generation. The present invention intends to improve the charge acceptability of a battery by releasing the heat generated on the negative electrode to the outside of the battery as quickly as possible and suppressing the temperature rise of the positive electrode to suppress oxygen generation from the positive electrode. Is.

Therefore, by using copper, which has good thermal conductivity, for the lead and terminal of the negative electrode, the heat generated on the negative electrode is promptly released to the outside of the battery.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sealed alkaline storage battery according to an embodiment of the present invention will be described below with reference to the drawings.

Powders in which nickel hydroxide, metallic cobalt and cobalt hydroxide were weighed in a weight ratio of 100: 7: 5 were mixed well, and then 20 g of the mixed powder was added with water to form a paste. This paste was filled into foamed nickel 60 mm wide, 81 mm long, and 3.1 g in weight, and after drying, the thickness was 1.74.
It was compressed to mm to obtain a positive electrode plate. A nickel plate as a lead was spot-welded to the corner of the positive electrode plate. Metallic cobalt contributes to ensuring the discharge reserve, and cobalt hydroxide contributes to improving the charging efficiency at 20 ° C. At this time, the theoretical capacity of one positive electrode plate is 5.05 Ah. This positive electrode plate is used for the test battery.
I used one.

A hydrogen storage alloy was used as the negative electrode. As hydrogen storage alloy, misch metal with 10% lanthanum content (M
used MmNi _3.5 Mn _0.4 Al _0.3 Co _0.75 containing m), and a paste by adding water in the same manner as in the alloy 19.4 g. This paste is filled in foamed nickel 60 mm wide, 81 mm long, and 3.1 g in weight, and dried to a thickness of 1.20.
It was compressed to mm to obtain a negative electrode plate. A copper plate having a width of 20 mm and a thickness of 0.2 mm was spot-welded to a corner of the negative electrode plate. At this time, the theoretical capacity of one negative electrode plate is 5.63 Ah. Six negative plates were used for the test battery.

As shown in FIG. 1, the negative electrode 2 and the positive electrode 3 were arranged in this order with the negative electrode on the outer side through the polypropylene nonwoven fabric separator 1 subjected to the sulfonation treatment. The negative electrode copper lead 4 was spot-welded to the nickel negative electrode terminal 5, and the positive electrode nickel lead was spot-welded to the nickel positive electrode terminal. These electrode plates were placed in a case 6 made of acrylonitrile-styrene resin having a thickness of 3 mm and having a length of 108 mm, a width of 69 mm, and a width of 18 mm. An aqueous solution of potassium hydroxide having a specific gravity of 1.3 was added as an electrolyte in an amount of 54 cc.

A sealing plate 8 made of acrylonitrile-styrene resin attached with a safety valve 7 operating at 2 atm was adhered to the case with epoxy resin. After that, the positive electrode terminal and the negative electrode terminal 5 were pressed and fixed to the sealing plate 8 via an O-ring to form a sealed battery. The battery of this example is designated as A. Further, as an example, B is a battery having substantially the same structure as the above, but using nickel of the same width and thickness for the lead 4 of the negative electrode and a copper terminal for the negative electrode terminal 4. A battery in which the copper negative electrode lead 4 and the negative electrode terminal 5 are used together is designated as C.

As a conventional example, a nickel negative electrode lead 4,
A battery using the negative electrode terminal 5 is designated as D. The batteries A to D have the same positive electrode theoretical fill capacity.

The batteries A to D were stored at 20 ° C. for 3 hours at a rate of 8.
After charging at 45 A for 4.5 hours, a charging / discharging cycle of discharging at a 5-hour rate of 5.06 A until the terminal voltage became 1 V was repeated.

The discharge curve at the 10th cycle is shown in FIG.
The battery of the present invention has a large discharge capacity and good charge acceptance.

[0025]

As is clear from the above description of the embodiments, the sealed alkaline storage battery of the present invention has improved charge acceptance and a large discharge capacity, which is of great industrial significance. ..

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention and a conventional sealed alkaline storage battery.

FIG. 2 is a graph showing discharge characteristics at the 10th cycle.

[Explanation of symbols]

 1 separator 2 negative electrode 3 positive electrode 4 negative electrode lead 5 negative electrode terminal

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Katsunori Komori 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Yoshinori Toyokuchi 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A chargeable / dischargeable negative electrode facing each other via a separator, a positive electrode made of nickel hydroxide, and an electrolyte containing an alkaline aqueous solution as a main component, and at least one of a lead and a terminal of the negative electrode is made of copper. Sealed alkaline storage battery.