JPH0451420Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Industrial application field This invention uses light metals such as lithium and sodium as negative electrode active materials, and uses perchlorine in an organic solvent such as propylene carbonate, 1.2 dimethoxyethane, and γ-butyrolactone as an electrolyte. The present invention relates to an organic electrolyte battery using a dissolved inorganic salt such as lithium oxide or lithium borofluoride, and particularly relates to a rechargeable secondary battery type organic electrolyte battery.

(b) Conventional technology As organic electrolyte batteries, primary batteries using manganese dioxide or carbon fluoride as positive electrode active materials have already been put into practical use, and in recent years, molybdenum trioxide, vanadium pentoxide, titanium disulfide, etc. Secondary battery systems using such materials as positive electrode active materials are being researched.

Now, a new problem arises in secondary battery systems that does not exist in primary battery systems. One of the important points is that during charging, the negative electrode active material, such as lithium, grows in a dendritic manner on the surface of the negative electrode plate and reaches the positive electrode plate or positive electrode can, thereby removing an internal short circuit, so that the charge/discharge cycle is short.

In order to eliminate such drawbacks, Utility Model No. 58-139672
The publication proposes covering the peripheral edge of the positive electrode plate with an insulating ring. Although this structure suppresses internal short circuits caused by dendritic growth of the negative electrode active material, the ring that covers the periphery of the positive electrode plate is originally intended to prevent the positive electrode plate from collapsing; Compared to this, the insulating ring has weak adhesion to the positive electrode plate, and repeated charging and discharging causes the positive electrode plate to collapse, resulting in a shortened cycle life.

(c) Problems to be solved by the invention The purpose of the invention is to suppress reduction in cycle life caused by dendritic growth of the negative electrode active material or collapse of the positive electrode plate.

(d) Means for Solving the Problems The battery of the present invention is characterized in that the peripheral edge of the positive electrode plate is covered with an insulating ring body having a porous conductor arranged on its inner surface.

(E) Effect Since the peripheral edge of the positive electrode plate is covered with an insulating ring, internal short circuits are suppressed even if the negative electrode active material grows in a dendritic shape, and a porous conductor is provided on the inner surface of the insulating ring. Therefore, the adhesion between the insulating ring body and the positive electrode plate is enhanced through this porous conductor, and collapse of the positive electrode plate is suppressed.

(F) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, numerals 1 and 2 are positive and negative electrode cans constituting a battery container, and are separated by an insulating packing 3. Reference numeral 4 denotes a negative electrode plate made of a rolled lithium plate, which is crimped to a negative electrode current collector 5 fixed to the inner bottom surface of the negative electrode can 2 .

6 is a positive electrode, which contains titanium disulfide as an active material, acetylene black as a conductive agent, and fluororesin powder as a binder in a weight ratio of 80:10:10.
The insulating ring body 7, which is the gist of the present invention, is made by integrally molding a mixture mixed at a ratio of .
The insulating ring body 7 is made of polypropylene, and as shown in FIG. 2, a porous conductor 8 such as a metal net is disposed on the inner surface in contact with the positive electrode 6.
This positive electrode 6 is pressed into contact with a positive electrode current collector 9 fixed to the inner surface of the positive electrode can 1 .

Reference numeral 10 denotes a separator for separating the positive and negative electrode plates, which is made of a polypropylene nonwoven fabric, and is impregnated with an electrolytic solution in which 1 mole of lithium perchlorate is dissolved in a mixed organic solvent of propylene carbonate and 1.2 dimethoxyethane. ing.

Figure 3 shows a battery A of the present invention having the above structure and a conventional battery B using a metal ring instead of an insulating ring.
This is a comparison diagram of cycle characteristics with battery C using an insulating ring body without a porous positive conductor arranged on the inner surface as disclosed in Japanese Utility Model Application Publication No. 58-139672, and the cycle conditions are as follows: When the current is 10mA, the charging end voltage is 4.0V, and when the discharging current is 5mA, the charging end voltage is 4.0V.
It was set to 1.5V.

It can be seen from FIG. 3 that the battery of the present invention has improved cycle characteristics.

Considering the reason for this, the peripheral edge of the positive electrode plate in the battery of the present invention is covered with an insulating ring, so even if the negative electrode active material grows in a dendritic shape, it is prevented from reaching the positive electrode plate, and internal short circuits are prevented. In addition, since a porous conductor is provided on the inner surface of the insulating ring, the adhesion between the insulating ring and the positive electrode plate is increased through this porous conductor, thereby suppressing the collapse of the positive electrode plate. By doing so, deterioration of cycle characteristics can be suppressed.

(g) Effects of the invention As described above, according to the invention, it is possible to obtain an organic electrolyte secondary battery with excellent cycle characteristics, and its practical value is extremely large.

[Brief explanation of drawings]

FIG. 1 is a half-sectional view of the battery of the present invention, FIG. 2 is a perspective view of an insulating ring body having a porous conductor on its inner surface, and FIG. 3 is a comparison diagram of cycle characteristics. DESCRIPTION OF SYMBOLS 1... Positive electrode can, 2... Negative electrode can, 3... Insulating packing, 4... Negative electrode plate, 6... Positive electrode plate, 7... Insulating ring body, 8... Porous conductor, 10... Separator.

Claims (1)

[Scope of utility model registration request] Positive and negative electrode plates are stacked via a separator in a battery container consisting of positive and negative electrode cans separated by insulating packing, and a porous conductor is arranged on the inner surface of the peripheral edge of the positive electrode plate. An organic electrolyte secondary battery characterized by being covered with an insulating ring body.