JP2976825B2 - Cylindrical sealed alkaline storage battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As well known, storage batteries used as various power sources include a lead storage battery and an alkaline storage battery. A typical system of the alkaline storage battery is a nickel-cadmium storage battery, and a nickel-hydrogen storage battery has been widely used.

[0003] The sealed type is widely used because of its easy handling, and an alkaline storage battery having such a nickel electrode as a positive electrode is formed by spirally winding a strip-shaped positive electrode plate, a negative electrode plate and a separator. The assembled electrode group is housed in a battery can to constitute a battery.

[0004] As a method of manufacturing an electrode, there are a sintering method, a foaming method, a paste method, and the like. A method of applying an active material paste to a porous core material such as a screen, an expanded metal, a punching metal, etc. It is advantageous in terms of price.

[0005] In addition, as a method for taking out terminals, apart from generally using no tab, a positive electrode plate is attached to a sealing lid with a positive electrode lead plate by welding, and a negative electrode is similarly attached to the bottom surface of a battery can by welding a lead plate. Attached. However, as batteries become smaller and smaller, it is difficult to weld the negative electrode lead because an electrode for welding needs to be inserted into the battery.
As proposed in Japanese Patent No. 10353, the outermost peripheral portion of the negative electrode plate was brought into contact with the inner wall of the battery can, so that the battery can was used as a negative electrode external terminal.

[0006]

However, when the battery can is used as a negative electrode terminal by bringing the outermost peripheral surface of such a negative electrode plate into contact with the inner wall of the battery can, in rapid charging and discharging,
The large contact resistance between the negative electrode plate and the battery can is one of the causes of the voltage drop. Therefore, in order to reduce the contact resistance, various measures have been studied with the aim of improving the conductivity of this part, but no sufficient solution has been found such as complicated processes or increased costs. .

An object of the present invention is to solve the above-mentioned problems and to provide a highly reliable battery having a battery can having a negative electrode terminal and having a low internal resistance.

[0008]

In order to achieve the above object, a cylindrical sealed alkaline storage battery according to the present invention comprises a battery can containing a group of electrode plates formed by winding a band-shaped positive electrode plate and a negative electrode plate via a separator. In the cylindrical sealed alkaline storage battery, the negative electrode plate has a burr or a burr of the negative electrode plate generated on a cut surface in a short direction of the negative electrode plate. It is wound so as to face the opposite outside, and is in contact with the battery can at the location of the burr or burr.

Further, in this case, the burr or burr of the negative electrode plate formed on the cut surface in the short direction of the negative electrode plate is directed to the center direction of the electrode plate group at the beginning of winding of the electrode plate group. It is preferably wound.

[0010]

According to the above construction, the contact between the outermost peripheral surface of the negative electrode plate and the inner wall of the battery can is caused not only by the active material layer but also by burr and burr.
That is, the contact resistance between the negative electrode plate and the battery can is reduced since the contact is also performed at the end of the core metal. For this reason, it is possible to provide a cylindrical sealed alkaline storage battery that suppresses a voltage drop during charging and discharging, has excellent current collection efficiency, and has good performance. Furthermore, by winding the burrs and burrs of the negative electrode plate at the beginning of the winding of the electrode group so as to face the center direction of the electrode group, it is possible to reduce defects due to an internal short circuit.

[0011]

Embodiments of the present invention will be described below.

For the positive electrode plate, a foamed metal core having a three-dimensional structure and a porosity of 90 to 95% is immersed in a nickel hydroxide paste prepared by mixing and stirring nickel hydroxide powder with a polyvinyl alcohol (PVA) aqueous solution. In this way, the active material was filled to make the material. The negative electrode plate was prepared by applying a cadmium paste prepared by mixing and stirring 100 parts by weight of cadmium oxide powder with 25 parts by weight of ethylene glycol on a core made of nickel-plated punched steel sheet having a porosity of 50%.

The large-sized positive and negative electrode plates thus prepared were cut into unit electrode plates for batteries. At this time, almost no burrs or burrs were found on the cut surface of the positive electrode plate.

Next, as shown in FIG. 1, the strip-shaped positive electrode plate 1 and the strip-shaped negative electrode plate 2 obtained as described above are spirally wound via a separator 3 made of a non-woven fabric of nylon to prepare an electrode plate group. Then, the burr or burr 4 of the negative electrode plate 2 at the end of winding of the electrode plate group was accommodated in the battery can 5 so as to contact the inner wall of the battery can 5. Then, an electrolyte mainly composed of potassium hydroxide was poured into the battery can 5 and sealed with a sealing plate to obtain an AA-size cylindrical sealed nickel-cadmium storage battery A according to the embodiment of the present invention. In the figure, reference numeral 6 denotes a core material of the negative electrode plate 2.

Next, an electrode plate is manufactured in the same manner as in the storage battery A of the embodiment, and the movable cutting blade 9 is vertically moved from the large-sized negative electrode plate 7 with respect to the fixed cutting blade 8 as shown by an arrow in FIG. Then, the negative electrode plate 2 as a unit electrode plate was cut by alternately cutting the large-sized negative electrode plate 7 from above and below. The burrs or burrs 4 formed on the cut surface of the completed negative electrode plate 2 as a unit electrode plate are turned in opposite directions on the cut surfaces facing each other. Using the electrode plate thus obtained, a battery was produced in the same manner as in the example battery A, and a cylindrical sealed nickel-cadmium battery B according to the example of the present invention was obtained. In addition,
At this time, the direction of the burrs or burrs 4 generated on the cut surface of the negative electrode plate 2 in the short direction is opposite to the center direction of the electrode plate group at the start of winding of the electrode plate group and opposite to the center direction of the electrode group at the end of winding. Each faces the outside.

Next, a negative electrode plate is formed in the same manner as in the above-mentioned storage battery A. When the negative electrode plate is wound through a separator in combination with the positive electrode plate, an electrode plate group is formed without specifying the direction of burrs or burrs. A nickel-cadmium storage battery was manufactured using such an electrode group, and a storage battery C according to a conventional example was obtained.

Each of the storage batteries A and B of the embodiment and the storage battery C of the conventional example were prototyped for 5000 cells each, and the internal resistance and the presence or absence of short-circuit failure were confirmed for all the batteries. Table 1 below shows the average value, standard deviation σ, and short-circuit failure rate of the internal resistance at that time.

[0018]

[Table 1]

The battery was evaluated at a charging current of 600 mA at 20 ° C., a charging time of 1.5 hours, and a discharging current of 120 m.
A, 600mA, 1200mA, 1800mA, 300
A charge / discharge test was performed under the conditions of 0 mA and a discharge end voltage of 1.0 V, respectively. FIG. 3 shows the amount of discharge electricity with respect to each discharge current value at this time.

As is clear from Table 1 and FIG. 3, burrs or burrs formed on the cut surface in the short direction of the negative electrode plate are located at the end of the winding of the electrode group at the outer side opposite to the center direction of the electrode group. By contacting the burrs or burrs at the end of the winding of the negative electrode plate with the inner wall of the battery can, the contact resistance is reduced and good results are obtained in terms of performance. at the same time,
The short-circuit failure rate at the winding end of the electrode group is reduced, and a highly reliable cylindrical sealed battery can be obtained. Further, by defining the direction of the burr or the burr at the winding start portion of the negative electrode plate on the center direction side of the electrode plate group, the short circuit failure rate can be further reduced.

[0021]

As described above, in a cylindrical sealed alkaline storage battery in which a group of electrode plates in which a strip-shaped positive electrode plate and a negative electrode plate are wound via a separator are housed in a battery can, the negative electrode plate is moved in the short direction. The burrs or burrs of the negative electrode plate generated on the cut surface of the above-mentioned electrode plate group are wound so as to face the outside opposite to the center direction of the electrode plate group at the end of winding of the electrode plate group, and the burrs or burrs By contacting the battery with the battery can, it is possible to provide a highly reliable sealed cylindrical alkaline storage battery in which the internal resistance of the battery is reduced, the voltage drop during discharging is suppressed, the short-circuit failure rate is low, and the reliability is high.

[Brief description of the drawings]

FIG. 1 shows a cylindrical sealed nickel alloy according to an embodiment of the present invention.
Cross section of cadmium storage battery

FIG. 2 is a diagram showing a method for manufacturing a negative electrode plate constituting the present invention.

FIG. 3 is a diagram showing a relationship between a discharge current value and a discharge electricity amount.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode plate 2 Negative electrode plate 3 Separator 4 Burr or burr 5 Battery can 6 Core material 7 Large size negative electrode plate 8 Fixed cutting blade 9 Movable cutting blade

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Jun Itami 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. In-company (58) Field surveyed (Int.Cl. ⁶ , DB name) H01M 10 / 04,10 / 28 H01M 4/24-4/26 H01M 6 / 10,6 / 16

Claims (2)

(57) [Claims] 1. A cylindrical sealed alkaline storage battery comprising a group of electrode plates formed by winding a band-shaped positive electrode plate and a negative electrode plate with a separator interposed therebetween in a battery can, wherein the negative electrode plate is formed on a cut surface in a short direction. The burrs or burrs of the negative electrode plate are wound so as to face the outer side opposite to the center direction of the electrode plate group at the end of winding of the electrode group, and the battery can is formed at the burrs or burrs. A cylindrical sealed alkaline storage battery, which is in contact with 2. The negative electrode plate is wound such that burrs or burrs of the negative electrode plate formed on a cut surface in a short direction of the negative electrode plate face a center direction of the electrode plate group at a starting portion of the electrode plate group. The sealed cylindrical alkaline storage battery according to claim 1, wherein