JPH039248Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a cylindrical battery having a structure in which positive and negative electrodes are arranged concentrically with a cylindrical separator in between, and particularly relates to a cylindrical separator.

(b) Prior art Non-aqueous electrolyte batteries and alkaline dry batteries are known as batteries with this type of structure, and the cylindrical separator is liquid resistant and has excellent liquid retention properties. Generally, woven or non-woven fabrics made of synthetic resin are used.

By the way, the synthetic resin woven fabric or nonwoven fabric mentioned above is composed of an aggregate of fibers, and this aggregate of fibers has voids or pores between the fibers, and the size of the pores is expressed as the pore diameter. Since these woven or nonwoven fabrics have large pores, one or both of the positive and negative electrode active materials migrate to the opposite electrode through the pores, causing self-discharge, resulting in a disadvantage that the battery capacity decreases. .

In order to eliminate this inconvenience, a separator with a double layer structure consisting of a first layer made of woven or non-woven synthetic resin fabric and a second layer made of a synthetic resin film having micropores is used. It is proposed that.

However, it has been found that even this double-layer separator has the following problems in the battery assembly process.

In other words, when assembling a battery, if a cylindrical unipolar electrode is placed on the inside surface of the battery container and a predetermined amount of electrolyte is injected, and then a double-layered cylindrical separator is assembled, the synthetic resin film will not be electrolyzed. Due to poor liquid permeability, it takes a long time for the electrolytic solution to diffuse through the cylindrical separator from the outer surface of the cylindrical separator to the internal space surrounded by the cylindrical separator, which slows down the battery assembly process. Above, there is a problem.

In addition, in order to improve the diffusivity of the electrolyte, if a separator with a double-layer structure with an opening at its lower end is used, one or both of the positive and negative electrode active materials will migrate to the counter electrode through this opening. As mentioned above, there is a problem that self-discharge occurs.

Furthermore, if the lower end of a double-layered cylindrical separator is simply sealed in order to prevent one or both of the positive and negative electrode active materials from migrating to the counter electrode, the electrolyte may be a synthetic material with poor electrolyte permeability. Since the electrolytic solution must pass through the resin film, the diffusivity of the electrolytic solution is further reduced, which is not preferable in terms of the battery assembly process.

(c) Purpose of the invention The present invention has been devised in view of the above-mentioned problems, and it effectively prevents the migration of the active material of one electrode to the opposite electrode, and prevents the electrolyte from flowing into the cylindrical separator. The purpose is to facilitate the diffusion of the battery and shorten the battery assembly time.

(d) Structure of the invention The cylindrical battery of the invention includes a cylindrical unipolar electrode disposed on the inner surface of a battery container that also serves as a unipolar terminal, and a cylindrical separator interposed in the hollow part of the unipolar electrode. and a terminal member of the other polarity electrically connected to the other polarity electrode. and a second layer made of a synthetic resin film having micropores, and at the lower end of the cylindrical separator, the first layer extends from the second layer to form an extended end. The cylindrical separator is characterized in that the lower end of the cylindrical separator is sealed by the extended end.

(E) Embodiment An embodiment of the present invention will be described below in detail with reference to the drawings, taking a non-aqueous electrolyte battery as an example.

Reference numeral 1 denotes a battery container which also serves as a positive electrode terminal, and a cylindrical manganese dioxide positive electrode 2 is disposed on its inner surface. 3 is a lithium negative electrode, and the positive electrode 2
A cylindrical separator 4 (details will be described later), which is the gist of the present invention, is placed in the hollow part of the separator 4 . Reference numeral 7 denotes a metal lid that closes the opening of the battery container 1. A negative electrode terminal pin 9 is fixed to the central through hole of the metal lid through an insulating material 8, and a lithium negative electrode is attached to the lower surface of the negative electrode terminal pin 9. One end of the lead plate 10 that can be led out from 3 is fixed.

Here, the cylindrical separator 4 has a first layer 5 made of polypropylene nonwoven fabric, as shown in FIG.
and a second layer 6 made of polypropylene film having a width slightly smaller than that of the first layer are stacked, and then rolled into a cylindrical shape, and then the overlapping portion is thermally welded 11 as shown in FIG. Also, this cylindrical separator 4
At the extended end, the first layer 5 is present alone and constitutes a single part 12, which is sealed. As a result, the cylindrical separator 4 is configured to enclose the lithium negative electrode 3.

(f) Effects of the invention According to the invention, there is a cylindrical unipolar electrode arranged on the inner surface of the battery container which also serves as a unipolar terminal, and a cylindrical separator arranged in the hollow part of the unipolar electrode. The cylindrical separator includes a first layer made of a woven or nonwoven fabric made of synthetic resin and a first layer made of a woven or nonwoven fabric made of synthetic resin. the first layer extends from the second layer to form an extended end at the lower end of the cylindrical separator. Since the lower end of the cylindrical separator is sealed by the extended end, there is a single portion of only the first layer that facilitates the diffusion of the electrolyte. Compared to a second layer, such as a synthetic resin film, which makes it difficult for the electrolyte to diffuse, it is difficult to diffuse the electrolyte through the extended end portion of the first layer, which is made of a woven or nonwoven fabric made of synthetic resin. Since the electrolytic solution is easily diffused into the cylindrical separator, the battery assembly process can be shortened.

Furthermore, since the lower end of the cylindrical separator is sealed, this is compared to a conventional cylindrical separator that is made up of only a double-layered cylindrical part without an extended end and that is open at the lower end. As a result, migration of the positive and negative electrode active materials through the openings of the separator can be prevented and self-discharge can be suppressed, so that a decrease in battery capacity can be suppressed.

[Brief explanation of the drawing]

The drawings are all related to the present invention; Fig. 1 is a longitudinal cross-sectional view of the battery of the invention, Fig. 2 is a diagram showing the state in which the first layer and the second layer are laminated to create a cylindrical separator, and Fig. 3 each shows a perspective view of a cylindrical separator. 1...Battery container, 2...Positive electrode, 3...Negative electrode, 4
... Cylindrical separator, 5 ... First layer, 6 ...
Second layer, 7... Metal lid, 8... Insulating material, 9...
Negative terminal pin.

Claims (1)

[Scope of utility model registration request] A cylindrical unipolar electrode placed on the inner surface of the battery container that also serves as a unipolar terminal, an other polarity electrode placed in the hollow part of the unipolar electrode with a cylindrical separator in between, and an electric current connected to the other polarity electrode. The cylindrical separator has a first layer made of a woven or nonwoven fabric made of synthetic resin and a second layer made of a synthetic resin film having micropores. At the lower end of the cylindrical separator, the first layer extends from the second layer to form an extended end, and the extended end forms a double layer of the cylindrical separator. A cylindrical battery characterized in that a lower end of a shaped separator is sealed.