JPH06101334B2 - Inorganic non-aqueous electrolyte battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention uses an alkali metal as a negative electrode active material, an oxyhalide as a positive electrode active material and a solvent for an electrolytic solution, and particularly an inorganic non-aqueous electrolytic solution excellent in low-temperature discharge characteristics. Regarding batteries.

[Conventional technology]

Conventionally, in an inorganic non-aqueous electrolyte battery using an alkali metal such as lithium or sodium as a negative electrode active material and an oxyhalide such as thionyl chloride, sulfuryl chloride or phosphoryl chloride as a positive electrode active material and a solvent for an electrolytic solution,
As shown in the figure, a cylindrical carbon porous molded body integrally formed is used for the positive electrode 3, and a cylindrical separator 6 and a cylindrical alkaline metal negative electrode 1 are provided around the cylindrical carbon porous molded body. A structure in which is arranged has been adopted (for example, JP-A-58-121563).

[Problems to be solved by the invention]

However, in the battery having such a structure, for example, a case of a lithium-thionyl chloride battery will be described as an example. When discharged at a low temperature, the diffusion rate of lithium ions is slow, and therefore the discharge reaction is almost the surface of the positive electrode. And the unreacted reaction product lithium chloride is deposited in the pores on the surface of the positive electrode 3 formed of the carbon porous molded body and fills the voids on the surface of the positive electrode, so that the discharge proceeds. Accordingly, the supply of substances necessary for the discharge reaction such as the electrolytic solution and the active material into the inside of the positive electrode 3 becomes poor, and as a result, the utilization rate of the positive electrode 3 decreases.

[Means for solving problems]

This invention solves the above-mentioned problems of the prior art, in which an alkali metal such as lithium or sodium is used as a negative electrode active material, and an oxyhalide that is liquid at room temperature such as thionyl chloride, sulfuryl chloride or phosphoryl chloride is used as a positive electrode active material. In an inorganic non-aqueous electrolyte battery using as a solvent of an electrolyte and a positive electrode formed by stacking a plurality of carbon porous molded bodies with a porous sheet having liquid permeability interposed therebetween, thereby achieving the object. Is.

That is, when a plurality of carbon porous molded bodies are stacked with a porous sheet having liquid permeability interposed therebetween to form a positive electrode, and the porous sheet having liquid permeability is arranged in the positive electrode, during discharge, Since the electrolytic solution and the active material can be supplied to the inside of the positive electrode through the porous sheet, even if lithium chloride, which is an insoluble reactive substance, is deposited in the pores on the surface of the positive electrode in the vicinity of the negative electrode, the utilization factor of the positive electrode is thereby increased. Is prevented and the low temperature discharge characteristics can be improved. Further, also in forming the positive electrode, it is only necessary to cut the carbon porous molded body formed by extrusion molding in the same manner as the conventional one into a shorter length than the conventional one and stack a plurality of it with a porous sheet having liquid permeability therebetween. , The formation of the positive electrode is easy and easy, and despite such a simple positive electrode formation
The remarkable effect of improving the low temperature discharge characteristics as described above is exhibited.

In the present invention, the porous sheet interposed in the positive electrode is
Any material that has liquid permeability and allows the electrolyte to pass therethrough and to supply the substances necessary for the discharge reaction such as the electrolyte and the active material to the inside of the positive electrode so as not to hinder the battery reaction is required. do not do. Therefore, as such a porous sheet,
A battery that can be used as a separator in this type of battery can be used, but a battery that does not have electrical insulation such as activated carbon fiber may be used. Specifically, as such a porous sheet, for example, a glass fiber nonwoven fabric,
A polyethylene non-woven fabric, a polypropylene non-woven fabric, a non-woven fabric mixed with glass fibers and polyethylene fibers, a non-woven fabric mixed with glass fibers and polypropylene fibers, and a non-woven fabric mixed with glass fibers and acrylic fibers are used. In particular, the glass fiber nonwoven fabric is preferably used in the present invention because it has excellent resistance to oxyhalides and also has a property of retaining an electrolytic solution.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of an AA lithium-thionyl chloride battery showing an embodiment of the inorganic non-aqueous electrolyte battery of the present invention.
In the figure, 1 is a negative electrode, and this negative electrode 1 is formed by pressing a 0.8 mm-thick lithium sheet onto the inner peripheral surface of a cylindrical battery case 2 made of stainless steel. 3 is a positive electrode, which has a porosity of 85% by volume, a diameter of 10.6 mm, and a height of 9.
A cylindrical carbon porous molded body 3a having a diameter of 7 mm was formed by stacking three porous sheets 4 having liquid permeability, and the carbon porous molded body 3a was composed of 90% by weight of acetylene black. 20 parts by weight of an aqueous dispersion of polytetrafluoroethylene (60% by weight of solid content), 120 parts by weight of methyl alcohol and 250 parts of water based on 100 parts by weight of a mixture of 10% by weight of graphite.
A kneaded product obtained by adding parts by weight is extrusion-molded and cut into a predetermined size. The porous sheet 4 having liquid permeability provided in the positive electrode 3 as described above has a thickness of 0.4 mm,
A glass fiber non-woven fabric with a porosity of 96% by volume was punched into a circle with a diameter of 10.6 mm. 5 is an electrolytic solution, which is a solution of 1.2 mol / l of lithium tetrachloroaluminate (LiAlCl ₄ ) as a supporting electrolyte in tiniol chloride, and the thionyl chloride is used as a solvent for the electrolytic solution. In addition, it is used as a positive electrode active material in this battery. 6, 7 and 8 are each 0.2m thick
m, a separator made of glass fiber non-woven fabric with a porosity of 96% by volume, bottom paper and top paper. Reference numeral 9 is a positive electrode current collector made of stainless steel. Reference numeral 10 denotes a battery lid, the main body of the battery lid 10 is made of stainless steel, and the outer peripheral portion is welded to the open end of the battery case 2. A positive electrode terminal 12 is provided in the center of the battery lid 10 via a glass seal 11. The positive electrode terminal 12 is formed by welding and sealing the upper portion of the stainless steel pipe 13 and the upper end portion of the positive electrode current collector 9.

The above battery is manufactured as follows.

The lithium sheet is pressure-bonded to the inner peripheral surface of the cylindrical battery case 2 to form the negative electrode 1, the separator 6 is arranged along the inner peripheral surface of the negative electrode 1, the bottom paper 7 is inserted, and then the separator 6 The hollow carbon porous molded body 3a on the inner peripheral side is attached to the porous sheet 4
The positive electrode 3 is formed by interposing 3 and inserting them so as to be stacked. Next, the top paper 8 is placed on the positive electrode 3, and if used, pressure is applied from above the top paper 8 to bring the respective members into close contact,
The battery cover 10 is fitted into the battery case 2 in this state, and the joint between the battery case 2 and the battery cover 10 is welded.

Next, the electrolyte 5 is attached to the battery lid 10 in advance by glass sealing.
Stainless steel pipes attached via 11 13
Then, the positive electrode current collector 9 is inserted into the pipe 13, the lower part of the positive electrode current collector 9 is embedded in the positive electrode 3 through the top paper 8, and then the positive electrode current collector 9 Upper end and pipe
Weld with 13 and seal. The positive electrode current collector 9 has a diameter of 0.
Although it is formed of a 7 mm stainless steel rod, the lower portion thereof has a needle shape, and the porous sheet 4 arranged in the positive electrode 3 also has a needle-like shape when the positive electrode current collector 9 is inserted into the positive electrode 3. It is pierced by the tip, and the lower end of the positive electrode current collector 9 reaches near the lower end of the positive electrode 3.

The battery of the above embodiment was designated as battery A, and lithium was used as a positive electrode 3 with a cylindrical carbon porous molded body having a conventional structure as shown in FIG. 2 and a porosity of 85% by volume, a diameter of 10.6 mm and a height of 29.0 mm. -Thionyl chloride battery was set to B, both batteries were continuously discharged at -40 ° C and 100Ω, and the discharge characteristics were examined. The results are shown in Fig. 3. In each of the battery A and the conventional battery B of the present invention, the amount of lithium was 530 mg and the amount of carbon in the positive electrode was 750.
In mg, the amount of electrolyte is 3.6 ml, which is the same in all cases.

As shown in FIG. 3, in the low temperature heavy load discharge of −40 ° C. and 100Ω, the battery A of the example of the present invention had a discharge capacity about 1.3 times that of the conventional battery B.

In addition, in the embodiment, when forming the positive electrode 3, three carbon porous molded bodies 3a were stacked with the porous sheet 4 having liquid permeability interposed therebetween, but when forming the positive electrode, a number of carbon porous molded bodies are stacked. It may be determined by determining the diameter and height of the positive electrode. From the viewpoint of improving the utilization rate of the positive electrode and improving the low-temperature discharge characteristics, it is preferable that a large number of porous sheets having liquid permeability are arranged in the positive electrode, but this increases the carbon content of the positive electrode. Since the discharge capacity is decreased and the discharge capacity is decreased from that side, and the current collecting ability on the positive electrode side is also decreased. It is preferable to stack four. Further, in the examples, as the porous sheet disposed in the positive electrode, a glass fiber nonwoven fabric having a thickness of 0.4 mm, which is larger than that used for the separator 6, was used. This is because the voids are less likely to be crushed and have excellent liquid retention. As the porous sheet having liquid permeability which is disposed in such a positive electrode, it is generally preferable to use one having a thickness of 0.2 to 0.6 mm. A circular sheet may be used as the porous sheet as illustrated in the examples, or the positive electrode current collector may be previously inserted into a portion where the positive electrode current collector is inserted so that the positive electrode current collector can be easily inserted. A hole having a diameter approximately the same as the diameter of the electric body may be opened.

Further, although the lithium-thionyl chloride battery has been described in the examples, the present invention is not limited to this case, sodium may be used as the negative electrode active material instead of lithium, and thionyl chloride may be used instead. Phosnolyl chloride or sulfuryl chloride may be used as the positive electrode active material and the electrolytic solution solvent.

〔The invention's effect〕

As described above, in the present invention, a positive electrode is formed by stacking a plurality of carbon porous molded bodies with a porous sheet having liquid permeability interposed therebetween to form an electrolytic solution into the positive electrode during discharge. It was possible to improve the low temperature discharge characteristics by improving the positive electrode utilization rate by improving the supply of the active material and the like.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an inorganic non-aqueous electrolyte battery of the present invention, FIG. 2 is a sectional view showing a conventional inorganic non-aqueous electrolyte battery, and FIG. 3 is a battery of the present invention. FIG. 3 is a discharge characteristic diagram of a conventional battery. DESCRIPTION OF SYMBOLS 1 ... Negative electrode, 3 ... Positive electrode, 3a ... Carbon porous molded object, 4 ... Liquid-permeable porous sheet, 5 ... Electrolyte, 6 ... Separator

Claims (2)

[Claims] 1. An inorganic non-aqueous electrolyte battery using an alkali metal as a negative electrode active material and an oxyhalide as a positive electrode active material and a solvent for an electrolytic solution, wherein a porous sheet having liquid permeability of a carbon porous molded article is provided. An inorganic non-aqueous electrolyte battery characterized in that a positive electrode is formed by stacking a plurality of electrodes with the electrodes interposed. 2. The inorganic non-aqueous electrolyte battery according to claim 1, wherein the porous sheet having liquid permeability is a glass fiber nonwoven fabric.