JPS58150273A - Organic electrolyte battery - Google Patents

Abstract

PURPOSE:To flatten the electric-discharge voltage of an organic electrolyte battery, and increase the closed-circuit voltage of the battery by installing at least two layers containing cupric oxide used as a positive active material on the separator side and on the bottom side of a positive can, and positioning a layer containing an iron sulfide used as a positive active material between said layers. CONSTITUTION:A positive electrode 1 is composed of a layer 1a containing an iron sulfide used as a positive active material, and two layers 1 containing cupric oxide used as a positive active material. One of the layers 1b touches a separator 2, and the other layer 1b touches the bottom of a positive can 3. The layer 1a containing an iron sulfide used as a positive active material, is positioned between the two layers 1b containing cupric oxide used as a positive active material. The separator 2 is made of a nonwoven polypropylene fabric. The positive can 3 is made of a nickel-plated iron plate. The symbol 5 represents a negative can made of a nickel stainless-steel clad plate. A negative electrode 7 is made by pressing and attaching a disk-like lithium to a stainless-steel net 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the improvement of an organic electrolyte battery using lithium as a negative electrode active material and iron sulfide and cupric oxide as positive electrode active materials. The purpose is to improve the closed circuit voltage during discharge.

Organic electrolyte batteries that use iron sulfide or cupric oxide as positive electrode active materials have a larger electrical capacity per unit volume and have a higher discharge capacity than organic electrolyte batteries that use manganese dioxide or carbon fluoride as positive electrode active materials. It has a voltage of about 1.5V and is compatible with commercially available Lecrancier batteries and silver oxide batteries, and is expected to develop as a high energy density battery with a large electrical capacity.

However, when iron sulfide is used as a positive electrode active material, there are problems such as discharge products accumulating on the positive electrode, causing the positive electrode to swell and increase in volume, causing the battery to swell and damaging equipment using the battery. In addition, when cupric oxide is used as a positive electrode active material, there are disadvantages such as a two-stage discharge reaction and a lack of flatness of the discharge voltage. It never got to the point where it was put to use.

Therefore, the present inventors have conducted extensive research in order to obtain a battery that takes advantage of the advantages of iron sulfide and cupric oxide while eliminating their drawbacks, and have mixed iron sulfide and cupric oxide. By using these as positive electrode active materials, it is possible to obtain an organic electrolyte battery with a flat discharge voltage, less battery swelling due to discharge, and a larger discharge capacity than when each of these is used alone. I discovered that
A patent application has already been filed for this, but as a result of further research, a positive electrode mixture containing iron sulfide and cupric oxide as positive electrode active materials was prepared and pressure-molded, and iron sulfide and cupric oxide were used as positive electrode active materials. A positive electrode is constituted by a layer using copper oxide as a positive electrode active material and a layer using cupric oxide as a positive electrode active material, and a layer using cupric oxide as a positive electrode active material is provided at least on the separator side and on the bottom side of the positive electrode can. When a layer containing iron sulfide as the cathode active material is placed between them, it has all the characteristics of using a mixture of iron sulfide and cupric oxide as the cathode active material. The present invention was completed based on the discovery that the discharge voltage becomes even more even and the closed circuit voltage during discharge is further improved.

The positive electrode is composed of a layer using iron sulfide as a positive electrode active material and a layer using cupric oxide as a positive electrode active material, and the layer using cupric oxide as a positive electrode active material is formed at least on the separator side and the positive electrode can. The reason why the discharging voltage is leveled and the closed circuit voltage is improved by placing the iron sulfide on the bottom side and a layer containing iron sulfide as the positive electrode active material is that it is not necessarily the case with the current method. Although it is not clear, the discharge voltage is flattened and the discharge voltage is slightly lower than iron sulfide because cupric oxide is placed in a position where the discharge reaction is likely to occur, so the discharge voltage of cupric oxide is initially appear,
Iron sulfide begins to discharge when the discharge of cupric oxide is almost completed, but as the resistance of the positive electrode increases slightly due to discharge, the voltage is only about the potential of cupric oxide, and from the beginning of discharge This is thought to be due to the fact that the discharge progresses at a voltage close to the potential of cupric oxide until the end of the discharge. Furthermore, the improvement in the closed-circuit voltage during discharge is considered to be due to the formation of highly conductive metallic steel in the early stage of discharge.

In the present invention, iron sulfides used include, for example, ferrous sulfide (FeS), ferric sulfide (Fe2S3), iron disulfide (FeS2), etc., and are generally commercially available as ferrous sulfide. When expressed by the general formula FexS, X is slightly smaller than 1, which can also be used in the same way as FeS. As the frozen electrolyte, for example, an electrolyte such as lithium perchlorate or lithium borofluoride is dissolved in a solvent such as propylene carbonate, γ-butyrolactone, tetrahydrofuran, 1,2-dimethoxyethane, dioxolane, etc. alone or in a mixture of two or more thereof. ◇ Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an organic electrolyte battery of the present invention,
(1) is a positive electrode, and this positive electrode (1) is composed of a layer (la) using iron sulfide as a positive electrode active material and a layer (1b) using cupric oxide as a positive electrode active material. Two layers (1b) containing cupric oxide as a positive electrode active material are provided, one of which is placed on the side in contact with the separator (2), and the other layer is placed on the bottom side of the positive electrode can (3). A layer (la) using iron sulfide as a positive electrode active material is arranged between the two layers (1b) using cupric oxide as a positive electrode active material. (4) is a stainless steel annular pedestal that reinforces the positive electrode (1), the separator (2) is made of polypropylene nonwoven fabric, and the positive electrode can (
3) is made of iron with nickel plating on the outside. (5
) is a negative electrode can made of nickel-stainless steel clad plate.
A stainless steel mesh (6) is spot-welded to the inner surface of the negative electrode can (5), and a disc-shaped lithium is crimped onto the mesh (6) to form a negative electrode (7). and (8)
is an annular gasket made of polypropylene.

The positive electrode (1) having an eight-layer structure as described above is produced, for example, as shown below. First, an annular pedestal is placed in a mold with its top and bottom reversed from the state shown in FIG. 1, and then a granular or powdered positive electrode mixture containing cupric oxide as a positive electrode active material is filled. This positive electrode mixture includes, for example, 88 parts of cupric oxide (parts by weight, hereinafter the same) and 15 parts of acetylene black.
1 part and 2 parts of polytetrafluoroethylene. After filling the positive electrode mixture, it is preformed by slight pressure, and then a granular or powdered positive electrode mixture containing iron sulfide as the positive electrode active material is filled thereon. Note that this positive electrode mixture consists of, for example, 83 parts of iron disulfide (FeS2), 15 parts of acetylene black, and 2 parts of polytetrafluoroethylene. Next, it is lightly pressurized and preformed again, and a positive electrode mixture containing cupric oxide as the positive electrode active material as described above is filled thereon, and pressurized and main molded.

In the present invention, the usage ratio of iron sulfide and cupric oxide (-) is in the range of 50 to 80% iron sulfide (by weight, the same applies hereinafter) and 50 to 20% cupric oxide. In particular, a range of 50 to 75% iron sulfide and 50 to 25% cupric oxide is preferable.In addition, when the positive electrode has a three-layer structure as described above, cupric oxide: iron sulfide substance: cupric oxide in a weight ratio of 1:2:l to 1:8:1, especially 1:2
The range is preferably 1 to 1.25: 7.50: 1.25.

Battery A with the above configuration and the positive electrode (
1) is the amount of electricity discharged when battery B, which has a single layer structure and uses a mixture of iron disulfide and cupric oxide as the positive electrode active material, is continuously discharged at 115Ω at 20°C to a final voltage of 1.2V. Fig. 3 shows the swelling of the battery, and Fig. 4 shows the closed circuit voltage after discharging for 0.1 second at -10°C, load 2, and Ω at 80% discharge.

In addition, the usage ratio of iron disulfide and cupric oxide is 50:
Battery A and Battery B in the case of 50 °C, Battery C using only iron disulfide as the positive electrode active material, and Battery C using only cupric oxide as the positive electrode active material in the case of 20°
FIG. 5 shows the discharge characteristics when the C1 load 15 is continuously discharged at Ω. Note that the positive electrode in battery A is CuO:F
The weight ratio of eS2:CuO is 1:2:1.

In both batteries, the positive electrode mixture composition was 8
Battery A and Battery B each have a positive electrode structure as shown in Figures 1 and 2, respectively, and contain iron disulfide, which is a positive electrode active material. The ratio of use with cupric oxide is varied. For batteries A-B, C, and D, the amount of positive electrode mixture used per positive electrode was 140 capes, and a lithium plate with a diameter of 6.81 M and a thickness of 1.8 fl was used as the negative electrode, and the electrolyte was Lithium perchlorate is dissolved in a mixed solvent with a volume ratio of propylene carbonate and 1.3-dioxolane of 1:1 at a ratio of 0.5 mol/l, and the battery has a diameter of 9.5 mm% and a height of 8.6 It is silk.

As shown in FIG. 3, battery A of the present invention has the characteristics of battery B in which iron disulfide and cupric oxide are mixed, but
As shown in the figure, the closed circuit voltage is higher than that of battery B, and the discharge voltage is flat.

In the example, the positive electrode (1) has an eight-layer structure, and the layer (1b) containing cupric oxide as the positive electrode active material is arranged on the side in contact with the separator (2) and on the side in contact with the bottom of the positive electrode can (3). death,
Although the layer (1b) containing iron sulfide as the positive electrode active material is placed between them, the positive electrode in the present invention is not limited to this. For example, the positive electrode may have a five-layer structure, and the first layer, that is, the side in contact with the separator. and the fifth layer, that is, the layer (1b) containing cupric oxide as the positive electrode active material on the side in contact with the bottom of the positive electrode can.
(~, the second layer is a layer (1a) using iron sulfide as a positive electrode active material, the third layer is a layer (1b) using cupric oxide as a positive electrode active material, and the fourth layer is a layer (1b) using cupric oxide as a positive electrode active material. A layer (la) containing iron sulfide as a positive electrode active material may be disposed on the surface of the layer (la), and cupric oxide may be further placed around the entire periphery of the layer (la) containing iron sulfide as a positive electrode active material. The layer (II) which is a positive electrode active material may be formed so as to be in contact with the layer (II).

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of an organic electrolyte battery of the present invention, and FIG. 2 is a cross-sectional view of an organic electrolyte battery having a structure different from that of the present invention. Figure 8 is a diagram showing the amount of electricity discharged and the swelling of the battery shown in Figures 1 and 2, along with changes in the usage ratio of iron disulfide (Fe S2 ) and cupric oxide (Cub); 2 is a diagram showing the closed circuit voltage of the battery shown in FIGS. 1 and 2 together with changes in the usage ratio of iron disulfide and cupric oxide. FIG. FIG. 5 is a discharge characteristic diagram of a battery according to the present invention and a battery having a configuration other than the present invention. (1)... Positive electrode, (1a)... Layer using iron sulfide as positive electrode active material, (1b)... Layer using cupric oxide as positive electrode active material, (2)... Separator, (3)...Positive electrode can, (7)...Negative electrode 4 1 2 3 Figure 3 Cub (%) 100 75 50 25 0
Ratio of FeS2 and CuO in positive electrode

Claims (1)

[Claims] 1. An organic electrolyte battery that uses lithium as a negative electrode active material and iron sulfide and cupric oxide as positive electrode active materials, the positive electrode comprising iron sulfide as the positive electrode active material. and a layer using cupric oxide as a positive electrode active material, and the layer using cupric oxide as a positive electrode active material is arranged at least on the separator side and the bottom side of the positive electrode can, and the iron sulfide layer is disposed in between. An organic electrolyte battery characterized by arranging a layer in which a substance is used as a positive electrode active material. 2. The ratio of iron sulfide to cupric oxide is 5.
The organic electrolyte battery according to claim 1, wherein the weight ratio is 0 to 75 and the cupric oxide content is 50 to 25.