JPH0850916A - Cylindrical sealed cell - Google Patents

Abstract

PURPOSE:To reduce faulty shortcircuiting caused by burrs due to cutting by making a negative plate wider in width than a positive plate, and winding them while both cut sections of the positive plate are being placed at the outsides of the positive plate at all times. CONSTITUTION:A positive plate 1 is formed by cutting a pole plate material which comprises active material filled in a substrate formed out of a foamed metal, into a rectangular sheet 35mm wide and 87mm long. And a negative plate 2 is formed by cutting a pole material composed of a nickel plated punching metal as a core member, which comprises active material composed mainly of cadmium oxide coated over its both sides, into a rectangular sheet 35.5mm wide and 120mm long. The positive and negative plates 1 and 2 are piled up to each other while a separator is being interposed in between, and are winded in a spiral form so as to be formed into a pole plate group. In this case, the cut sections of the negative plate 2 in the longer direction at its upper and lower sides are so set as to be placed at the outsides of the cut sections of the positive plate 1 in the longer direction. Since almost no burr due to cutting is produced out of the foamed metal consisting of the substrate material of the positive plate 1, this constitution thereby permits faulty shortcircuiting to be reduced, through which burrs due to cutting are produced while the separator is being penetrated through.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spiral wound electrode plate group for a cylindrical sealed battery.

[0002]

2. Description of the Related Art In recent years, with the development of cordless equipment, a cylindrical sealed battery has become widespread as a power source thereof. In particular, a sealed nickel-cadmium storage battery is a typical example, and a sealed nickel-hydrogen storage battery and a lithium ion battery have been added.

The electrode plate of these cylindrical sealed type batteries has a method in which a porous material such as expanded metal or punching metal is coated with an active material paste as a core material, and the active material paste is cut into a desired size by a press and used. It is popular because it can be expected to reduce costs.

The electrode plate 2a having a predetermined size, which is manufactured by the method of cutting with the press blade 6, is usually formed as shown in FIG.
Cutting burr 5 of the core material 7 protruding on the cut end faces parallel to each other
However, as shown in FIG. 4 (B), they face in opposite directions. When this electrode plate is wound in a spiral shape, the burr 5 of the core material 7 facing outward is subjected to tensile stress on itself as shown in FIG. , It tends to protrude outward in the vertical direction and penetrates the separator to come into contact with the counter electrode, which often causes a short circuit failure.

[0005]

[Patent Document 1] Japanese Unexamined Patent Publication No. 1-25
As described in Japanese Patent No. 5172, if the positive electrode plate and the negative electrode plate are shifted in the width direction and wound, and only one end face of each of the positive and negative electrode plates is opposed to each other via the separator, the above-described short circuit failure occurs. The probability should be halved. However, in reality, when the positive and negative electrode plates 1 and 2 are displaced in the width direction and wound in a spiral shape, one end face of the positive and negative electrode plates 1 and 2 is guided as shown in FIG. Since it is wound without being regulated by No. 3, there are many winding misalignment defects, and the defect rate cannot be sufficiently reduced. In addition, 4 is a winding core.

It is an object of the present invention to provide a highly reliable cylindrical sealed battery by improving the above problems in spiral winding.

[0007]

In order to achieve this object, according to the present invention, the width of the negative electrode plate among the positive and negative electrode plates in which a separator is placed between them and wound in a spiral shape is set to that of the positive electrode plate. The negative electrode plate is wound so that the cut portion in the longitudinal direction is on the outside of the positive electrode plate on both the upper and lower sides, or one of the positive and negative end faces of the negative electrode plate in the longitudinal direction is wound. And the cutting burr on the side of the negative electrode plate aligned with the end surface of the positive electrode plate is spirally wound so as to face the center direction of the electrode plate group.

[0008]

When a positive electrode plate and a negative electrode plate are arranged with a separator in between and spirally wound, the most serious problem is a short circuit between the electrode plates. The main causes of this are cutting burrs that occur when the positive and negative electrode plates are cut to a specified size, and a burr short circuit that penetrates the separator and conducts to the other pole, and the positive and negative electrode plates are not sufficiently parallel to the longitudinal direction. There is a winding deviation short circuit that occurs when a portion is wound in a state and is not insulated by the separator.

Therefore, if the width of the negative electrode plate is made wider than that of the positive electrode plate, and the end faces in the longitudinal direction of the negative electrode plate are wound so as to be outside the positive electrode plate on both upper and lower sides, the cutting burr of the negative electrode plate is positive. Since it does not face the plate, it is considered that a short circuit due to it does not occur. However, when the electrode plate group is actually wound by this method, as shown in FIG. 1, since the positive electrode plate 1 is not regulated by the guides 3 on both upper and lower end surfaces in the longitudinal direction, winding deviation easily occurs. As a countermeasure against this, as shown in FIG. 2, positive and negative electrode plates 1,
It is effective to prevent winding deviation by aligning one of the upper and lower end faces of 2 in the longitudinal direction and regulating the aligned side by the guide 3, but the problem of burr short circuit at the place where the end faces are aligned again is solved. Occurs.

As described above, in the constant feed type cutting, since the cutting burrs face opposite directions on both end surfaces of the cut electrode plate, as shown in FIG. 5 (B).
If the direction of the cutting burr 5 coincides with the center direction of the wound electrode plate group, the burr is unlikely to project to the outside. It may be configured so that the winding center direction of the electrode plate group matches.

In the electrode plate group thus constructed, the positive electrode lead terminals are arranged on the side where the positive and negative electrode plates are aligned so that the lead terminals of the positive electrode plate do not come into contact with the negative electrode plate. It may be stored toward the opening side of the can that also serves as a terminal.

This structure is extremely effective in a battery using a positive electrode having a foam metal as a substrate, since the burr short-circuit is mostly caused by the negative electrode plate using punching metal.

[0013]

【Example】

(Embodiment 1) Hereinafter, an embodiment of the present invention will be described with reference to a specific example.

A positive electrode plate 1 having a width of 35 mm and a length of 87 mm, in which a substrate made of foam metal is filled with an active material, and iron and Ni.
Width 35.5 mm, length 12 with active material mainly composed of cadmium oxide coated on both sides of plated punching metal
A 0 mm negative electrode plate 2 is prepared. Since the positive electrode plate 1 has a core material made of foam metal, cutting burrs do not occur when the positive electrode plate 1 is cut into a certain size, but the negative electrode plate 2 is cut by a constant size feed as shown in FIG. Cutting burrs 5 are formed on the upper and lower sides (left and right sides) of the end faces in opposite directions.

By using these positive and negative electrode plates 1 and 2, FIG.
As shown in FIG. 4, the longitudinally cut portion of the negative electrode plate 2 is spirally wound so that both the upper and lower sides thereof are outside the longitudinally cut portion of the positive electrode plate 1, and the 4 / 5A type nickel cadmium is wound. A battery electrode group A was constructed.

Next, using the same positive and negative electrode plates, as shown in FIG. 2, one end face (upper side in the figure) of the negative electrode plate and one end face of the positive electrode plate are aligned and aligned. The electrode plate group B is configured such that the protruding direction of the burr protruding from the cut end surface on the aligned side of the negative electrode plate 2 and the central direction of the wound electrode plate group are aligned while the side is regulated by the guide 3. did.

For comparison, the width of the negative electrode plate is 35 mm, which is the same as the width of the positive electrode plate as in the conventional case, and both the upper and lower end faces in the longitudinal direction are spirally wound in alignment with the end face of the positive electrode plate based on the conventional method. Plate group C was constructed.

Table 1 shows the results of inspecting 5,000 short circuit defects due to burrs and winding misalignment defect ratios for each of the three types of electrode plate groups A, B and C thus constructed.

[0019]

[Table 1]

As is clear from (Table 1), it is understood that the electrode plate groups A and B according to the present example are improved in the total defective rate as compared with the electrode plate group C according to the comparative example.

[0021]

As described above, according to the present invention, by using the negative electrode plate having a width wider than that of the positive electrode plate, it is possible to obtain a cylindrical sealed battery having higher reliability than conventional ones.

[Brief description of drawings]

FIG. 1A is a front view showing an example of a wound state of positive and negative electrode plates according to the present invention. FIG.

FIG. 2A is a view showing another example of the positive and negative electrode plates in a wound state according to the present invention. FIG. 2B is a top view of the same.

FIG. 3 is a diagram showing a wound state of positive and negative electrode plates according to a conventional example.

FIG. 4A is a diagram showing a process of cutting an electrode plate by a constant feed method and a plate plate that has been cut. FIG. 4B is an enlarged view of a main part of A.

FIG. 5 (A) A state diagram in which the electrode plate is wound with the cutting burr direction facing outwards. (B) A state diagram in which the electrode plate is wound with the cutting burr direction facing inside.

[Explanation of symbols]

 1 Positive Electrode Plate 2 Negative Electrode Plate 3 Guide 4 Winding Core 5 Cutting Burr 6 Cutting Blade 7 Core Material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norio Suzuki, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A cylindrical sealed battery in which a separator is placed between a positive electrode plate and a negative electrode plate and the whole electrode plate group wound in a spiral shape is housed in a can, and the width of the negative electrode plate is the positive electrode. A cylindrical sealed battery characterized in that it is wider than that of the plate, and that the longitudinal cut portion of the negative electrode plate is located outside both the upper and lower sides of the positive electrode plate in the longitudinal direction. 2. A cylindrical sealed battery in which a separator is disposed between a positive electrode plate and a negative electrode plate and the whole electrode plate group wound in a spiral shape is housed in a can, and the width of the negative electrode plate is the positive electrode. It is made wider than that of the plate, and one of the upper and lower end faces of the cut portion in the longitudinal direction of the negative electrode plate is aligned with one end face in the longitudinal direction of the positive electrode plate, and the burr or burrs of the cut portion of the negative electrode plate are projected. It is wound so that the direction is directed toward the center side of the spiral electrode plate group, and the side where the end faces of the positive and negative electrode plates of the electrode plate group are aligned is stored toward the opening side of the can body. Cylindrical sealed battery.