JPH05135756A - Battery with spiral electrode plate group - Google Patents

Abstract

PURPOSE:To provide a battery capable of satisfactorily preventing a short circuit between electrode plates by improving a separator in the battery stored with an electrode plate group spirally wound with a belt-like positive electrode plate, a negative electrode plate, and the separator into a case. CONSTITUTION:A separator partially deposited with a main separator 3 made of heat-solving synthetic resin fibers and an auxiliary separator 5 shorter than the main separator 3 in length and 0.5-2.0 times heavier than the main separator 3 in weight per unit area is arranged on the outside of the winding start portion of one electrode plate on the inside to constitute an electrode plate group. The increase of the volume of the separator is made the minimum required, and the short circuit of the electrode plate group can be prevented without preventing the increase of the capacity of a battery.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery having a case in which a positive electrode plate, a negative electrode plate and a separator each having a strip shape are spirally wound.

[0002]

2. Description of the Related Art Batteries provided with a spiral electrode plate group are widely known as cylindrical Ni-Cd storage batteries, lithium batteries and the like.

FIG. 5 is a cross-sectional view showing a typical structure of a battery provided with a conventional spiral electrode plate group. In FIG. 5, 1 is a positive electrode plate, 2 is a negative electrode plate, and 3 is a long strip-shaped separator, and the positive electrode plate is wrapped with the separator 3 in a spiral shape. In the battery thus configured, since there is only the separator 3, only the central portion of the separator forming the winding core of the electrode plate group has a double structure.

[0004]

However, since only a long strip-shaped separator is used, burrs are generated at the edge of the tip of the electrode plate and burrs caused by cracks at the small bending radius of the tip of the winding start. Therefore, there is a problem that the separator is broken and a contact short circuit between the positive electrode plate and the negative electrode plate is likely to occur frequently.

Further, with the increase in capacity of batteries, thin separators have been adopted. In this case, the weight per unit weight of the separator is increased or the separator is doubled in order to prevent a short circuit between the electrode plates. But,
This results in poor gas permeability. In addition, there is a problem that the electrolyte distribution becomes non-uniform.

The present invention solves the above-mentioned problems of the prior art by using a main separator for originally separating the electrode plates and a sub-separator having a shorter length than the main separator to the minimum necessary amount. By constructing the plate group, it is an object to favorably prevent a short circuit between the electrode plates.

[0007]

In order to achieve this object, the battery of the present invention is provided with a main separator and a longer length than that at least in a portion having a small bending radius which is a winding start portion of one inner electrode plate. A spiral electrode plate group is configured by arranging a sub separator having a short length, and a separator in which the main separator and the sub separator are partially welded in advance by ultrasonic waves or heat is used.

[0008]

With this structure, it is possible to prevent a short circuit due to burrs generated at the leading edge of the electrode plate or burrs due to cracks in the electrode plate having a small bending radius by the two main and sub separators. Furthermore, instead of making the length of the sub separator the same as the length of the main separator, the sub separator is arranged only in the portion where short circuits between the electrode plates frequently occur,
Further, in order to prevent misalignment, the main separator and the sub-separator are not welded by an adhesive that may react with the active material or the electrolytic solution, but by ultrasonic waves or heat,
By increasing the separator volume to the minimum necessary and keeping the electrode plate volume large, it is possible to increase the capacity of the battery.

[0009]

EXAMPLES Examples of the present invention will be described below.

As shown in FIG. 1, a nickel electrode is used as the strip-shaped positive electrode plate 1, a cadmium electrode is used as the negative electrode plate 2, and nylon 6 non-woven fabric is used as both the main and sub separators, and the nominal capacity is 5
An AA size battery of 00 mAh was constructed. At that time, as shown in FIG. 2, the sub separator 5 having a length of 15 mm was welded to the main separator 3 having a total length of 145 mm at the winding start portion of the electrode plate group.
Shows the number of short-circuit defects between electrode plates per 10,000 electrode plate groups when the weight per unit weight of the sub separator 5 is changed from 0.2 to 3.0 times the weight per unit weight of the main separator 3. .. For comparison, the number of short-circuit defects between the electrode plates when the conventional sub separator is not used is also shown.

[0011]

[Table 1]

As the weight per unit area of the sub separator with respect to the main separator increases, the number of short circuit defects between the electrode plates also decreases. However, when the basis weight is 2.5 or 3.0 times, there is a problem that it is difficult to secure the battery capacity because the separator volume increases. In this case, it is possible to reduce the thickness, but when the thickness is reduced, there is a problem that the reactivity becomes poor.

[0013]

[Table 2]

Therefore, it can be seen from this result that it is effective when the weight per unit area of the sub separator is 0.5 to 2.0 times that of the main separator.

Further, as shown in FIGS. 3 and 4, when the sub-separator 5 is arranged outside the electrode plate located inside the winding end portion of the electrode plate group, the winding start and winding end of the electrode plate group are Similar effects can be obtained even when they are arranged on both sides.

The second embodiment uses nylon 6 for the main separator 3 and nylon 66 for the sub separator 5. When the basis weight of the sub separator 5 was changed to 0.2 to 3.0 times the basis weight of the main separator 3, the same result as that of the first example was obtained.

[0017]

As described above, in the battery provided with the spiral electrode plate group of the present invention, the main separator and the sub-separator, which are heat-soluble synthetic resin fibers, are heat-welded to each other so that the separator is a minimum necessary amount. By providing the battery in a volume, it does not hinder the increase in battery capacity, minimizes the non-uniform distribution of liquid and the deterioration of gas permeability, and prevents burrs from occurring at the tip edge of the electrode plate and bending at the beginning of winding. It is intended to realize an excellent battery capable of preventing a short circuit between electrode plates due to burrs or the like due to cracks generated in a portion having a small radius.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a battery in which a sub separator is arranged at a winding start portion of an electrode plate group.

FIG. 2 is a development view of an electrode plate group in which a sub separator is arranged at a winding start portion of the electrode plate group.

FIG. 3 is a cross-sectional view of a battery in which an auxiliary separator is arranged at the winding end portion of an electrode plate group.

FIG. 4 is a cross-sectional view of a battery in which a sub separator is arranged at the winding start portion and the winding end portion of the electrode plate group.

FIG. 5 is a cross-sectional view of a battery including a conventional spiral electrode plate group.

[Explanation of symbols]

 1 Positive Electrode Plate 2 Negative Electrode Plate 3 Main Separator 4 Case 5 Sub Separator 6 Center of Winding

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Inaba ▲ Yoshi ▼ 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A battery comprising a case in which a group of electrode plates, which are spirally wound strip-shaped positive electrode plates, negative electrode plates and separators, are housed in a case.
At least on the outside of the winding start part of one of the inner electrode plates,
A main separator made of a heat-soluble synthetic resin fiber and a separator in which a sub-separator having a length shorter than this main separator is partially heat-welded are arranged, and the sub-separator is made of the same material as the main separator, A battery comprising a spiral electrode plate group having a basis weight of 0.5 to 2.0 times that of the main separator. 2. The spiral electrode plate group according to claim 1, wherein the main separator and the sub separator are made of different materials of fibers of nylon 6, nylon 66, polypropylene, polyethylene and a mixture of the fibers. With a battery.