JPS59128772A - Nonaqueous solvent battery - Google Patents

Abstract

PURPOSE:To increase discharge capacity and high rate discharge efficiency by using a porous carbon body having a specified range of porosity and pore distribution ratio as a positive electrode. CONSTITUTION:A cylindrical negative electrode 2 comprising metallic lithium is pressed in the inside of a can 1. A positive electrode 3 is placed in the inside of the negative electrode 2 with a separator 4 interposed. Thionyl chloride (SOCl2) solution containing LiAlCl4 is poured in the can 1. A porous carbon body whose porosity is 70-85% and distribution ratio of pores having a pore size of 0.1-2mum is 30% or more is used for the positive electrode. Thereby, a positive active material is easily supplied to the porous carbon body 6, and the reaction surface area is also increased. Therefore, a lithium-thionyl chloride battery having good high rate discharge performance and large discharge capacity is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a non-aqueous solvent battery, and particularly to a non-aqueous solvent battery with an improved positive electrode material.

[Technical background of the invention and its problems]

Nonaqueous solvent batteries that use lithium and sodium as negative electrode active materials have high energy density, excellent storage characteristics, and a wide operating temperature range, and are often used as backup power sources for calculators, watches, and memories. Such acidity consists of a negative electrode, an electrolyte, and a positive electrode. Generally, the negative electrode is an alkali metal such as lithium or sodium, and the electrolyte is propylene carnate, γ-
A solution prepared by dissolving an electrolyte such as persalted lithium wood oxide or lithium fluoroborate in a nonaqueous solvent such as butyrolactone or dimethoxyethane is used, and manganese dioxide, graphite fluoride, or the like is used as the positive electrode, respectively.

Among the above-mentioned batteries, so-called lithium-thionyl chloride batteries, which use lithium for the negative electrode and thionyl chloride (SOCl2) as the main positive electrode active material, are attracting attention because of their particularly high energy density.

These batteries have a positive electrode made of a porous carbon body and a metal current collector, and generally have thionyl chloride (S) in which lithium chloride (LiC4) and aluminum chloride (htct
OCl2) is used as the electrolyte.

Therefore, 5OCt2 serves both as a positive electrode active material and as an electrolyte.

By the way, in a battery using 5OCt2 as the positive electrode active material, the negative electrode reaction is a reaction in which the negative electrode metal dissolves in the electrolyte as metal ions, while the positive electrode reaction occurs on the porous carbon material that is one of the constituent materials of the positive electrode. (b) This is a reaction in which the main reaction product is mainly formed on the surface of the porous carbon body. However, the table shows that in conventional batteries having a positive electrode made of a porous carbon body obtained by mixing acetylene black with a polymer binder such as polytetrafluoroethylene, molding it into a predetermined shape, and drying it, the reaction When the composition is formed on the porous carbon body, the electrode reaction is severely inhibited and the discharge capacity is reduced. Moreover, in the above-mentioned battery, 1. The disadvantage is that the discharge efficiency is significantly lower than that of low current discharge.

[Purpose of the invention]

The present invention aims to provide a non-aqueous solvent battery with excellent discharge capacity and discharge efficiency during large current discharge.

[Summary of the invention]

The present inventor focused on the fact that the inhibition of the electrode reaction by the main reaction components on the surface of the porous bamboo carbon body of the positive electrode is significantly influenced by the porosity and pore diameter of the porous carbon body. By using a positive electrode made of a porous carbon body with a specified pore diameter and a defined occupation ratio of pores with the specified diameter,
A non-aqueous solvent battery has been discovered that has excellent discharge power and discharge efficiency during large current discharge.

That is, the present invention comprises a cylindrical negative electrode made of an alkali metal provided on the inner surface of the can body, a positive electrode made of a porous carbon body and a metal current collector, and disposed inside the can body inside the negative electrode with a separator interposed therebetween. , in a non-aqueous solvent battery containing thionyl chloride as a main component housed in the can body and comprising an electrolytic solution that also serves as a positive electrode active material, the porous carbon body of the positive electrode has a porosity of 70 to 85%; It is characterized by using a structure in which pores of 0.1 to 2 tsn occupy 30 or more of the total pores.

The reason for limiting the porosity of the porous carbon body is that if the porosity is less than 70%, the reaction efficiency will decrease, whereas if it exceeds 85%, it will cause a decrease in the strength of the porous carbon body. It is. In addition, 30 of the pores in this porous carbon body
The reason for limiting the diameter of pores larger than
If it is less than μm, the pores will be blocked by the acid due to the reaction of thionyl chloride, which is the positive electrode active material, leading to a decrease in battery function.
On the other hand, if it exceeds 2 μm, the reaction area of the porous carbon body decreases, which leads to a decrease in reaction efficiency.

Furthermore, the reason why the proportion of 0.1 to 2 μm pores in the total pores is limited is that if the proportion is less than 301, it will not be possible to sufficiently increase the reaction efficiency.

The above-mentioned positive electrode is manufactured, for example, by the method shown below. A polymer binder such as polytetrafluoroethylene is mixed with a carbon material such as carden black, a solvent such as ethyl alcohol is added, and the mixture is sufficiently stirred and kneaded.Then, the mixed wire is made into wire mesh, punch metal, or Exno J. A positive electrode is produced by pressing the electrode onto a metal current collector 5 such as a metal current collector and drying it.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a lithium-thionyl chloride battery, and numeral 1 in the figure is a can made of, for example, stainless steel and having an open top that also serves as a negative electrode terminal. A cylindrical negative electrode 2 made of metallic lithium is pressure-bonded to the inner surface of the can 1. Inside the can body 1 inside the negative electrode 2, a positive electrode is provided via a plate 4 made of a non-woven glass fiber fabric placed on the inner surface of the negative electrode 2. Note that an insulating paper 5 is interposed between the positive electrodes and the bottom surface of the can body 1.

The positive electrode 1 includes a cylindrical porous carbon body 6 with a porosity of 70 to 85% and pores of 0.1 to 2 μm occupying 30 or more of the total pores, and a hollow inner surface of the porous carbon body 6. A cylindrical metal current collector 7 is provided.

Furthermore, the separator 4 is placed inside the can body 1 above the positive electrode l.
An insulating paper 8 supported by the insulating paper 8 is disposed. A metal top 9 is sealed to the upper opening of the can body 1 by laser welding or the like. This metal top 9
A hole 10 is bored in the center of the hole. Inside the can body 1 is thionyl chloride (SOCl2) in which LiAlCl4 is dissolved.
An electrolytic solution consisting of a solution is injected and contained through the hole 10. Further, a positive electrode terminal 11 is electrically insulated and fixed in the hole 10 of the metal top 9 by a metal-glass sealing material 12. According to the present invention, the porous carbon body 6 of the positive electrode 1 has a porosity of 7.
Since the structure is such that pores of 0 to 85% and 0.1 to 2 μm occupy 30 or more of the total pores, it is easy to supply the positive electrode active material to the porous carbon body 6, and the reaction surface area is increased. As a result, a lithium thionyl chloride battery with excellent high rate discharge characteristics and large discharge capacity can be obtained.

Next, specific examples of the present invention will be described.

Example 1 Average particle size 40 mμm, DBP oil absorption 1jly 20
0cm! Polytetrafluoroethylene was mixed with 10 wt % of polytetrafluoroethylene into carbon black with highly developed 1/100, q struts, and then ethanol was added and thoroughly kneaded. This mixed wire was molded together with a metal current collector 7 from a stainless steel net so that the current collector 7 was disposed on the inner peripheral surface to make a cylindrical object.
A positive electrode support was prepared by forming a cylindrical porous carbon body 6 which was dried under vacuum at a temperature of 0.degree. The porous carbon body 6 of this positive electrode l has a porosity of 8
When the pore distribution was investigated using the mercury intrusion method, it was found that 0
．． Pores of 1 to 2 μm accounted for 37% of the total. Next, this positive electrode plate is housed in a can body 1 with a negative electrode 2 crimped onto the inner peripheral surface via a separator 4, an insulating paper 8 is placed, a metal top 9 is sealed, and a metal top is placed inside the can body 1. 1.8 mol of LiAlCl4 dissolved through hole 10 of 9
After accommodating an electrolytic solution consisting of a concentrated thionyl chloride (SOCl2) solution, the positive and other terminals 11, which were previously connected to the metal current collector 7 via leads, were fixed in the holes 10 of the metal top 9 via the sealing material 12. The AA size lithium thionyl chloride battery shown in FIG. 1 was assembled.

Example 2 Average particle size: 30 mμm, DBP oil absorption: 185 cm
A positive electrode was prepared in the same manner as in Example 1 using 3/100 g of slightly developed 9-carden black with stratus. The porous carbon body of this positive electrode has a porosity of 82, and the proportion of pores of 0.1 to 2 μm in total pores is 34.
It was from q6. Next, using this positive electrode, the lithium thionyl chloride battery shown in FIG. 1 was assembled in the same order as in Example 1.

Comparative example average particle size 30 mμm11 DBP oil absorption Zoo cI
A positive electrode was prepared in the same manner as in Example 1 using carton black with a less developed structure of n''/1009, and this positive electrode was further used to construct a lithium thionyl chloride battery having the same structure as shown in FIG. Assembled.

The porous carbon body of the positive electrode has a porosity of 849-chi, and the proportion of pores of 0.1 to 2 μm in the total pores is 2.
It belonged to 4chi.

When the relationship between discharge capacity and discharge current was investigated for the batteries of Examples 1 and 2 and the battery of Comparative Example, the characteristic diagram shown in FIG. 2 was obtained. In addition, A in Figure 2
B is the characteristic curve of the battery of Example 2; B is the characteristic curve of the battery of Example 2; and C is the characteristic curve of the battery of Comparative Example. As is clear from Fig. 2, the battery of the present invention (A, B in the figure) has almost the same discharge capacity as the conventional battery (Φ in the figure) in small current discharge, but in large current discharge. It can be seen that the discharge capacity is extremely large.

Note that in the above embodiments, a cylindrical positive electrode was used, but the positive electrode is not limited to this. For example, car? A spiral positive electrode may be used, in which a mixture of plastic, resin, and a polymer binder is crimped onto a metal current collector to form a strip, which is then wound and dried.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to provide a non-aqueous solvent battery that has a significantly improved discharge capacity -10 and excellent discharge efficiency.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a lithium thionyl chloride battery showing one embodiment of the present invention, and FIG. 2 is a characteristic diagram showing the relationship between discharge current and discharge capacity in the battery of the present invention and a conventional battery. 1...Can body, 2...Negative electrode, Mutual...Positive electrode, 4...
Separator, 6... Porous carbon body, 7... Metal current collector, 9... Metal top, 11... Positive electrode terminal. Applicant's representative Patent attorney Takehiko Suzue 11-years old 3-4-10, Minamishinayo, Tokyo Parts Ward Toshiba Battery Co., Ltd. 0 Applicant Toshiba Battery Co., Ltd. 3-chome Minamishinayo, Tokyo Parts Ward No. 4 No. 10

Claims (1)

[Claims] A cylindrical negative electrode made of an alkali metal provided on the inner surface of the can, and a cell A? A non-aqueous non-aqueous cathode disposed through a lattice plate, comprising a cathode made of a porous carbon body and a metal current collector, and an electrolytic solution containing thionyl chloride as a main component and serving as a cathode active material housed in the can body. In the solvent battery, the nonaqueous solvent is characterized in that the porous carbon body of the positive electrode has a porosity of 70 to 85 cm and a structure in which pores of 0.1 to 2 μm occupy 30 cm or more of the total pores. battery.