JP2000036302A - Organic electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electrolyte battery equipped with an enhanced low-temp. discharge characteristic. SOLUTION: An organic electrolyte battery has a bundle of spiral electrodes 4 formed by winding a sheet-form positive electrode plate 1 and a sheet-form negative electrode plate 2 with a separator 3 interposed, wherein the positive electrode plate 1 consists of a positive electrode working substance, electroconduction agent, and a binder while the negative electrode plate 2 consists of alkali metal or its alloy. As positive electrode working substance, two sorts of manganese dioxide are used; one is electrolytic manganese dioxide A which is subjected to a heat treatment in the temp. range 380-460 deg.C and whose specific surface area ranges 40-80 m2/g and the other is electrolytic manganese dioxide B which is subjected to a heat treatment in the temp. range 350-430 deg.C and whose specific surface area ranges 15-20 m2/g. Use of the type A manganese dioxide enhances the low-temp. discharge characteristics while the type B manganese dioxide maintains the discharge characteristics a1 room temp., and good balance between the room temp. and low temp. is obtained by making the mix proportion so that the content of the type A ranges 10-40 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an organic electrolyte battery,
In particular, the present invention relates to a lithium battery, and more particularly, to an organic electrolyte battery in which a positive electrode material is improved to improve its low-temperature discharge characteristics.

[0002]

2. Description of the Related Art An organic electrolyte battery, particularly a lithium battery, having a positive electrode using manganese dioxide as an active substance and a negative electrode using an alkali metal or an alloy thereof as an active substance has a high energy density. It has been put to practical use as a power source for many electronic devices. This organic electrolyte battery is currently used for applications such as cameras, but as multi-functionality of electronic devices such as cameras progresses, batteries as power sources also have well-balanced discharge characteristics over a wide temperature range, especially There is a demand for higher discharge characteristics at low temperatures.

[0003]

SUMMARY OF THE INVENTION Under the circumstances described above, a conductive agent which has been mixed with manganese dioxide of the positive electrode,
Alternatively, a low-viscosity electrolytic solution, a high-conductivity electrolytic solution, and the like have been studied. However, even in these methods, the low-temperature discharge characteristics were not particularly satisfactory.

[0004] The present invention has been made in view of the above problems, and has as its object to improve the low-temperature discharge characteristics of an organic electrolyte battery by improving the positive electrode active substance.

[0005]

In order to achieve the above object, the present invention provides a sheet-like positive electrode plate comprising a positive electrode active substance, a conductive agent and a binder, and a sheet-like negative electrode plate comprising an alkali metal or an alloy thereof. In an organic electrolyte battery having a spiral electrode group wound around a separator,
As the positive electrode active substance, electrolytic manganese dioxide A having a specific surface area of 40 to 80 m ² / g by heat treatment at a temperature of 380 to 460 ° C. and a specific surface area of 15 to 20 m ² / g at a temperature of 350 to 430 ° C. g of electrolytic manganese dioxide B and two types of manganese dioxide, wherein the ratio of electrolytic manganese dioxide A is in the range of 10 to 40 wt%.

In the present invention, a mixture of two kinds of manganese dioxides having different heat treatment temperatures and specific surface areas at a fixed ratio is used as a positive electrode active substance. By using manganese dioxide having a large specific surface area, the positive electrode mixture is activated, and the discharge characteristics at low temperatures are improved. However, on the other hand, the discharge characteristics at room temperature are deteriorated. Therefore, a mixture of manganese dioxide having a small specific surface area is used to prevent the deterioration of the discharge characteristics at room temperature. When the above mixing ratio, that is, the ratio of the electrolytic manganese dioxide A to the total amount of the electrolytic manganese dioxide A and the electrolytic manganese dioxide B is in the range of 10 to 40 wt%, it is possible to prevent the discharge characteristics from dropping at room temperature while maintaining the low temperature. Discharge characteristics can be improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a main configuration of an organic electrolyte battery CR123A according to one embodiment of the present invention. (Preparation of sample manganese dioxide) 1) Electrolytic manganese dioxide A Electrolytic manganese dioxide having an average particle size of 7 μm, a bulk density of 0.55 g / cm ³ , and a specific surface area of 126 m ² / g by a BET method was subjected to ammonia neutralization at a temperature of 460 ° C. It was prepared by heating for 8 hours. The specific surface area by the BET method after the heat treatment is 43.
m ² / g.

2) Electrolytic manganese dioxide B Average particle size 25 μm, bulk density 1.52 g / cm ³ , BET
An electrolytic manganese dioxide having a specific surface area of 44 m ² / g by an ammonia neutralization treatment was prepared by heating at 370 ° C. for 8 hours. The specific surface area by the BET method after the heat treatment is 17
m ² / g.

(Example 1) In FIG. 1, a sheet-like positive electrode plate 1 was prepared as follows. That is,
90 parts by weight of a mixture of the above electrolytic manganese dioxide A and the above electrolytic manganese dioxide B in a weight ratio of 3: 7 (mixing ratio of manganese dioxide A 30 wt%) as a positive electrode active substance, and 5 parts of graphite powder as a conductive agent. Parts by weight and 5 parts by weight (as a solid content) of an aqueous dispersion of polytetrafluoroethylene (PTFE) as a binder were kneaded to prepare a positive electrode mixture, and this positive electrode mixture was applied to a stainless expanded metal. Thereafter, the sheet-shaped positive electrode plate 1 was dried and rolled, cut into a predetermined shape, and dried again. Also, a lithium aluminum alloy foil as a negative electrode active material is cut into a predetermined size to form a sheet-shaped negative electrode plate 2, and a part of the negative electrode current collector plate 7 made of an L-shaped nickel-plated steel plate
It was crimped to a part of.

Next, the sheet-like positive electrode plate 1 and the sheet-like negative electrode plate 2 are spirally wound through a separator 3 made of a microporous film made of polypropylene.
Electrode group 4 was obtained. An end portion of the negative electrode current collector plate 7 protruding from the lower surface of the electrode group 4 is bent inward in an end surface of the electrode group 4 via an insulating plate 8 made of resin, and this is opened into an opening of an outer can 5 serving also as a negative electrode terminal. It was inserted into the outer can from the end, and resistance welding was performed on the inner bottom surface of the outer can 5 and the end of the negative electrode current collector plate 7 at the portion 9 in the figure.

After the electrode group 4 is housed in the outer can 5 as described above, lithium trifluorometasulfonate (LiCF ₃ SO _{3) is} added to a mixed solvent of propylene carbonate and 1,2-dimethoxyethane at a mixing ratio of 3: 7. ) Is 0.5mo
1 / l of the dissolved organic electrolyte is injected in a predetermined amount, and the positive electrode lead 6 protruding from the upper surface of the electrode group 4 is resistance-welded to the bottom surface of the sealing body 10. And the positive electrode terminal 11 was fixed by caulking to assemble the organic electrolyte battery CR123A.

(Example 2) The above-mentioned electrolytic manganese dioxide A and electrolytic manganese dioxide B were used as positive electrode active substances in a ratio of 1: 9.
And the mixing ratio of manganese dioxide A is 10w.
An organic electrolyte battery having the same configuration as in Example 1 was prepared, except that the battery was changed to t%.

(Example 3) The above-mentioned electrolytic manganese dioxide A and electrolytic manganese dioxide B were 4: 6
And the mixing ratio of manganese dioxide A is 40w.
An organic electrolyte battery having the same configuration as in Example 1 was prepared, except that the battery was used in an amount of t%.

Comparative Example 1 The above-mentioned electrolytic manganese dioxide A and electrolytic manganese dioxide B were used in a ratio of 5: 5
The mixing ratio of manganese dioxide A is 50 w
An organic electrolyte battery having the same configuration as that of Example 1 was prepared, except that the battery was changed to t%, and Comparative Example 1 was obtained.

(Comparative Example 2) The above-mentioned electrolytic manganese dioxide A and electrolytic manganese dioxide B were used as positive electrode active substances in a concentration of 0.1%.
An organic electrolyte battery having the same configuration as that of Example 1 was prepared except that a mixture of manganese dioxide A was mixed at a weight ratio of 5: 9.5 to 5 wt% to obtain Comparative Example 2. .

Comparative Example 3 An organic electrolyte battery having the same structure as in Example 1 was prepared except that electrolytic manganese dioxide A was not used as the positive electrode active substance and only electrolytic manganese dioxide B was used. Comparative Example 3 was obtained.

(Evaluation) For each battery prepared above,
The low-temperature discharge characteristics and continuous discharge characteristics were evaluated, and the results are shown in Table 1.

1) The low-temperature discharge characteristics were as follows: 20 batteries were subjected to 1200 mA intermittent discharge (discharge in which a constant current of 1200 mA was passed for 3 seconds and paused for 7 seconds) in an atmosphere at a temperature of -20.degree. The electric capacity up to 5 V was obtained, expressed as a ratio (%) when the value of Comparative Example 3 was set to 100, and the average value was shown in Table 1.

2) Continuous discharge characteristics are as follows: 20 batteries were subjected to 100Ω continuous discharge in an atmosphere at a temperature of 20 ° C.
The electric capacity up to the end voltage of 2.0 V was obtained, expressed as a ratio (%) when the value of Comparative Example 3 was set to 100, and the average value was shown in Table 1.

[0020]

[Table 1]

As can be seen from Table 1, by mixing electrolytic manganese dioxide having a large specific surface area such as electrolytic manganese dioxide A, the positive electrode mixture is activated, and the discharge characteristics at -20 ° C. According to the mixing ratio 10w
In the case of t% (Example 2), an improvement in characteristics exceeding 10% was observed, and in the case of a mixing ratio of 50 wt% (Comparative Example 1), 5%.
0% improvement in characteristics was obtained. But on the other hand,
As for the discharge characteristics at 20 ° C., the results with the mixing ratio of 50 wt% (Comparative Example 1) were the lowest. This is because, by increasing the mixing ratio of the manganese dioxide A, the density at the time of manufacturing the positive electrode plate decreases, the mass as the positive electrode mixture decreases, and the discharge capacity decreases. Mixing ratio 5wt%
In (Comparative Example 2), the discharge characteristics at −20 ° C. were improved by only 3%, and the effect of mixing the electrolytic manganese dioxide A was not obtained. Value.

From the above results, when two types of electrolytic manganese dioxide, electrolytic manganese dioxide A and electrolytic manganese dioxide B, are used and the mixing ratio of electrolytic manganese dioxide A is in the range of 10 to 40 wt%, It can be seen that the discharge characteristics at −20 ° C. can be improved without significantly lowering the discharge characteristics at 20 ° C. When the mixing ratio of the electrolytic manganese dioxide A is lower than 10 wt%, -20
When the mixing ratio of the electrolytic manganese dioxide A exceeds 40 wt%, the discharge characteristics at 20 ° C. are significantly reduced.

In addition to the above, manganese dioxide A has an average particle size of 7 μm, a bulk density of 0.55 g / cm ³ , and a BE.
The electrolytic manganese dioxide of the ammonia neutralization treatment having a specific surface area of 126 m ² / g by the T method is heat-treated at 380 ° C. and 420 ° C. for 8 hours, and the specific surface area by the BET method after the heat treatment is 76 m ² / g and 60 m ² / g. Was prepared as manganese dioxide B, having an average particle size of 25 μm and a bulk density of 1.
52 g / cm ³ , BET specific surface area 44 m ² / g
Manganese dioxide for ammonia neutralization at a temperature of 35
BE after heat treatment at 0 ° C and 430 ° C for 8 hours
Specific surface area by T method of 20 m ² / g and 15 m ² / g
Was prepared. Then, each manganese dioxide A and each manganese dioxide B are mixed at a mixing ratio of manganese dioxide A of 10
組 み 合 わ せ 40 wt% and mix and mix each
The organic electrolyte battery CR was obtained in the same manner as in the example.
123A was assembled and evaluated. As a result, excellent evaluation was obtained in the same manner as in the above example.

[0024]

As described above, the organic electrolyte battery of the present invention can be applied in a wide temperature range because it improves the discharge characteristics at low temperatures and does not lower the discharge characteristics at room temperature.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of a main part of an organic electrolyte battery according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sheet-shaped positive electrode plate, 2 ... Sheet-shaped negative electrode plate, 3 ... Separator, 4 ... Electrode group, 5 ... Outer can, 6 ... Positive electrode lead, 7 ...
Negative electrode current collecting rod, 8: insulating plate, 9: resistance welded part, 10: sealing body, 11: positive electrode terminal.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Fujita, Inventor Koji Fujita 3-4-10, Minamishinagawa, Shinagawa-ku, Tokyo Inside Toshiba Battery Corporation (72) Eiji Otomo 3-4-1, Minamishinagawa, Shinagawa-ku, Tokyo No. Toshiba Battery Co., Ltd. F term (reference) 5H003 AA01 AA02 BA01 BB04 BD01 BD04 BD05 5H014 AA02 BB01 CC01 EE10 HH01 HH06 HH08 5H015 AA02 BB01 CC01 DD01 EE01 HH01 HH06 HH11 5H024 AA03 AA12 H01H02 H02 H01 H02 AL11 BJ02 BJ14 HJ01 HJ07 HJ14

Claims (1)

[Claims] 1. A spiral electrode group formed by winding a sheet-shaped positive plate made of a positive electrode active substance, a conductive agent and a binder, and a sheet-shaped negative plate made of an alkali metal or an alloy thereof through a separator. In the organic electrolyte battery having a positive electrode active material, electrolytic manganese dioxide A having a specific surface area of 40 to 80 m ² / g by heat treatment at a temperature of 380 to 460 ° C. and a specific surface area of heat treatment at a temperature of 350 to 430 ° C. An organic electrolyte battery using two types of manganese dioxide, namely, electrolytic manganese dioxide B having a concentration of 15 to 20 m ² / g, and the ratio of electrolytic manganese dioxide A in the range of 10 to 40 wt%.