JPS58135575A - Nonaqueous electrolyte cell - Google Patents

Abstract

PURPOSE:To obtain a cell extremely excellent in a long shelf life by using manganese dioxide with the X value of MnOx of 1.85-1.95 for a lithium-manganese dioxide cell. CONSTITUTION:85%, by weight, of electrolyzed MnOn (gamma) heated in the atmosphere, 10% of graphite as a dielectric material, and 5% of Teflon powder as a binding agent are mixed and molded into a positive electrode 2. Metal lithium is used for a negative electrode 4, and propylene carbonate of nonaqueous solvent and 1, 2 dimethoxyethane are mixed equally, by volume, and are dissolved with one mole of lithium perchlorate to be used as the electrolyte. The positive and negative electrodes are inserted physically and electrically in contact with a positive electrode can 1 made of SUS434 stainless steel and a negative electrode can 3 made of SUS304 stainless steel respectively, and a separator 5 made of polypropylene nonwoven fabric is inserted between both electrodes. Finally, the cell is assembled by fully bending the edge of the positive electrode can 1 inward through a gasket 6 made of polypropylene.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-aqueous electrolyte battery using manganese dioxide as a positive electrode active material, and particularly to the composition of manganese dioxide.

-The manganese dioxide used in this cell is M
They are collectively known by the chemical formula n01,
In reality, the crystal structure of Mn01 and the amount of attached water and bound water vary due to differences in the ore of Mn01, manufacturing methods, and heat treatment conditions for removing water.

It is becoming clear that there are differences in the amount ratio of Mn and 0. Furthermore, it is said that Mn0IKOH groups and excess oxygen may be bonded.

M n O@ having such a difference t has physical, chemical, and vapor chemical properties tsrc, and naturally has a significant influence on batteries combined with lithium. Conventionally, this type of non-aqueous electrolyte battery, unlike alkaline batteries such as Senbatsu batteries, does not leak due to alkaline solution seepage, but when the battery is stored for a long time or at high temperatures. When stored at high temperatures, leakage often occurred. Even when holes and leakage do not occur, the drawbacks are blockage of the battery and a large drop in the low closed-circuit voltage.

These problems are of course related to the sealing properties of the battery, but as a result of experimental studies conducted by the present inventors, the main cause was found to be based on differences in Mn01 itself.6 The present invention is based on these findings. Among the many types of Mn01, which are collectively referred to as Mn01, it was possible to significantly improve the leakage resistance of batteries by using one with a certain stoichiometric composition as an active material.

The details will be explained below using examples.

Example (1) Commercially available electrolytic MnJ (γ)1 was heated at 480°C in the atmosphere.
Heated for 24 hours, weight 85W5, 101i% graphite as a conductive agent, 5s Teflon powder as a binder.
F was mixed and acidified to obtain positive electrode 2.

Metallic lithium is used as the negative electrode 4, and propylene carbonate as a non-aqueous solvent and 1,2 dimethoxyethane are mixed in an equal volume ratio as the electrolyte, and 1 mole of lithium persalt saccharide is dissolved as the electrolyte. , and the positive and negative poles are f3U, respectively.
Positive electrode can 1.8US50 made of fj4s4 stainless steel
It was inserted into an electrode can 5 made of 4 stainless steel in physical electrical contact with it, with a separator 5 made of a KH volvn birene nonwoven fabric interposed between the electrodes. Finally, the battery is connected to the positive electrode can 1 via a gasket 6 made of polypropylene.
It was assembled by bending the ends inward. Their structures are as shown in FIG. Note that the battery size in this case is an outer diameter of 20 mm and a total thickness of 6 mm.

Example (2) Using the same lot of commercially available electrolytic Mn01 (γ) as in Example (1) heated in the atmosphere at 450°C for 24 hours, a battery was made in the same manner as in Example (1). Assembled.

Example (5) Using commercially available electrolytic UNO SNOW D) from the same lot as Example (1) heated in the atmosphere at 380°C for 24 hours, a battery was made in the same manner as Example (1). Assembled.

Example (4) Commercially available electrolytic Mn01 (γ) of the same lot as Example (1) was heat-treated in the atmosphere at 580°C for 24 hours, and then added to propylene carbonate, a non-aqueous solvent, used as the electrolyte. After soaking at 70°C for 8 hours, and then vacuum drying, assemble the battery in the same manner as in Example (1).

Next, powder 1- (stiff powder is hereinafter referred to as ABOD) obtained by heat treatment of actual bar examples (1) to (4) and immersion treatment in a non-aqueous solvent after heat treatment, and the total Mn content. Mn0xI:r)X
When ll was investigated, the results shown in Table 1 were obtained. These treatments were actually repeated three times, so their average values and maximum and minimum values are shown.

Table 1 Next, 10 liters of each of these ponds were stored in high humidity, and the amount of S* resistant 2W pond flakes and changes over time in the low-temperature closed circuit voltage were examined. Specifically, it was stored at 60°C and 95% RH for up to 120 days, and the leakage rate, W,
The amount of water leakage and the closed circuit voltage after 5 seconds with a 500Ω load at -10°C were established. These results are shown in Table 2. The battery blockage amount and low temperature closing voltage in the table are 100
This is the average value for 5 batteries.

In addition, among these percentage characteristics, the low-temperature closed circuit voltage value, which changes particularly after storage, is shown as a graph in Figure 412, and the symbols a, b, and cH in the graph, respectively, and xll of UNIX are calculated from the results in Table 91. , the ranges are categorized and organized from the lowest X value.

As is clear from these results, the actual M of MnO snow
It can be seen that the 1% storage property is significantly affected by the ratio of n and O. The reason for this is not clear, but another experiment showed that the larger the X value, the more Mn01t'i becomes chemically active, and tends to decompose propylene carbonate used in the electrolyte and generate carbon dioxide gas. It has been found.

As a result, it is thought that due to the high activity, the closed circuit voltage is high at the beginning of battery manufacture, or that gas is generated in the lightning pond due to the above phenomenon at high temperatures or after long-term storage, causing battery blockage and leakage. It will be done.

On the other hand, as shown in the examples, when Mn01(γ) is heat-treated at high temperature or immersed in propylene carbonate at high temperature, phase change of ijMnol occurs in the former case, and in the latter case, , the unstable oxygen on Mn0g, excess * elements, and oH groups react with propylene carbonate and are removed, so the X value decreases, the activity 11H decreases, and the closed circuit voltage of the battery initially decreases slightly. Although the temperature is low, the above-mentioned phenomenon is unlikely to occur at high temperatures or after long-term storage, so it is considered to be stable.

As described above in detail, the present invention provides a suitable value for the amount ratio of Mn and O, that is, an X value of MnOx of 1.85 to 1.
By using 1 nganese dioxide, which is 95, in a lithium '-manganese dioxide battery, it has become possible to provide an excellent secondary battery after long-term storage.
Its industrial value is extremely large.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of a pond according to an embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view of a pond according to an embodiment of the present invention. It is a graph showing the relationship. 1°''゛Positive can 2...Positive electrode 5...Negative electrode can 4...Negative electrode 5...Separator 6...Gasket Applicant Toji-Elli Co., Ltd. Tamasha Figure 1 Figure 7

Claims (1)

[Claims] A positive electrode made of manganese dioxide as a living material, a negative electrode made of lithium, and a gold salt of lithium used as an electrolyte. In a non-aqueous electrolyte battery consisting of a dissolved electrolyte, the manganese dioxide has an oxygen content of 18% relative to the manganese IK.
Non-aqueous electrolyte batteries with a ratio of 5 to 1,950 were used.