JPH05271824A - Production of lithium-aluminum alloy powder - Google Patents

Abstract

PURPOSE:To easily, efficiently and inexpensively produce an Li-Al alloy powder without any segregation and having a uniform composition by press-fixing an Al foil and an Li foil to each other in an inert atmosphere, heating and alloying the laminate and pulverizing the alloyed foil. CONSTITUTION:An Li foil 1 and an Al foil 2 are simultaneously passed between press rollers 3 in a working box (not shown in the figure) in an inert atmosphere of gaseous Ar, etc. In this case, both foils have the same thickness, and the Al foil 2 is made about 10mm wider. The foils are fixed to each other while leaving the Al foil on both ends. The Li-Al foil is then heated by a hot plate 4. The surface temp. of the plate 4 is controlled above the m.p. of Li or preferably at 300-500 deg.C, and the Li and Al are alloyed. The obtained Li-Al alloy foil and the surplus Al are wound on a winding roller 8, crushed by a crushing roller 5, dropped into a crusher 6 and further pulverized to collect the Li-Al alloy powder on a receiving dish 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a lithium / aluminum alloy mainly used as an electrode material for a lithium thermal battery or a secondary battery, and particularly to a lithium / aluminum alloy having a volume ratio of 50:50. The present invention relates to a technique for producing powder by a simple process in a short time.

[0002]

2. Description of the Related Art In recent years, miniaturization, weight reduction, and cordlessness have been promoted in electric equipment, communication equipment, and the like, and in response to this, demand for primary and secondary batteries using lithium has been increased. One of the electrode materials used for these electrodes is a powdery one, which is an alloy with a volume ratio of lithium to aluminum of 50:50.

By the way, as a method for obtaining such a lithium-aluminum alloy powder, there is known a method in which lithium and aluminum are melted to obtain an alloy lump, and then the alloy lump is pulverized into powder. This melting / solidifying / crushing method includes the following steps.

[1] Melting Step After weighing a lithium metal block and an aluminum metal block, they are put into a melting furnace and well stirred.

[2] Cooling / Solidifying Step: A mold prepared in advance is poured and cooled.

[3] Pulverizing step The size of the lump is adjusted to a size that can be easily put into the pulverizer, and then the lump is put into the pulverizer to obtain powder.

[0007]

The above-mentioned melting, solidifying, and pulverizing methods have a problem in that they have a large variety of equipment and require relatively large machines and jigs. That is, a melting furnace and a stirrer are required in the melting step, and a mold is required in the cooling / solidifying step. Further, a pressing machine, a hammer, a crusher and the like for the crushing process are required.

Moreover, the temperature of the molten metal for alloying is 7
It reaches 00 ° C, requires a lot of heat energy, there is a lot of material loss during melting, and segregation due to the difference in specific gravity in the molten metal is likely to occur, so control at the time of casting to obtain a uniform composition The problem was that it was very difficult. Furthermore, it is necessary to completely cool the mold and the alloy until crushing is possible, but natural cooling requires a long time, so in order to improve productivity, use a cooling device in the cooling / solidifying process. It had to be used, and it was inevitable that the entire equipment would become larger and the equipment cost would increase. Therefore, an object of the present invention is to provide a method for producing a lithium-aluminum alloy powder capable of efficiently producing a segregation-free lithium-aluminum alloy powder with a small amount of heat energy by a simplified process and small-scale equipment. Where it is.

[0009]

DISCLOSURE OF THE INVENTION The present inventors have noticed that a lithium foil produced in an inert gas such as argon gas exhibits a very high activity, and it is disclosed in Japanese Patent Laid-Open No. 2-33.
As disclosed in Japanese Patent No. 10327, it has succeeded in partially alloying this lithium foil by pressure-bonding a metal to be alloyed such as aluminum. This is a foil obtained by adjusting the thicknesses of the lithium foil and the metal foil to be alloyed to form a two-layer foil including a lithium alloy layer and a metal layer to be alloyed such as aluminum.

The present invention is a further development of this technical idea, and it has been clarified that a foil composed only of an alloy layer of lithium and aluminum can be obtained instead of a two-layer structure,
By crushing and pulverizing this, lithium
It was determined that an aluminum alloy powder could be obtained.

That is, the method for producing a lithium-aluminum alloy powder according to the present invention is characterized in that an aluminum foil and a lithium foil are pressure-bonded and heated in an inert atmosphere to be alloyed and then pulverized.

More specifically, the manufacturing method comprises the following steps. That is, a step of feeding a lithium foil and an aluminum foil wider than the lithium foil between the pressure bonding rollers to perform pressure bonding, a step of alloying by holding the pressure bonded product in a heated state at a temperature equal to or higher than the melting point of lithium, and being alloyed. It is a method for producing a lithium-aluminum alloy powder, which comprises a step of crushing a rolled foil and a step of winding the remaining aluminum portion.

[0013]

In the method for producing a lithium-aluminum alloy powder according to the present invention, as described above, a highly active lithium foil is pressure-bonded to an aluminum foil, and the pressure-bonded product is held in a heated state to form a lithium-aluminum alloy. Since the alloy foil is only crushed and pulverized after the production, the workability and the productivity are good, large equipment is not required, and the production cost is remarkably superior. Further, unlike the melting method, there is no material loss and segregation does not occur, so that the components can be made uniform.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given below with reference to the schematic view of a manufacturing apparatus shown in the accompanying drawings. In this example, argon gas is selected as the inert atmosphere, and the manufacturing apparatus is installed in a work box filled with dried argon gas.

First, a lithium foil 1 extruded to have a thickness of 0.1 mm and a width of 130 mm and an aluminum foil 2 having a thickness of 0.10 mm and a width of 140 mm are set at the feeding position, and the tips are aligned to form a pair of pressure bonding rollers 3. Insert in between.

This is because aluminum and lithium are pressure-bonded with the same thickness and alloyed to make a volume ratio of 50:
This is to ensure that an alloy having a composition of 50 is obtained. The reason why the aluminum foil 2 is made 10 mm wider than the lithium foil 1 is that the lithium-aluminum alloy is fragile and does not have sufficient tensile strength. It is designed to withstand force, which allows the lithium-aluminum alloy to move smoothly and reliably through the process. The foil that has been sufficiently pressure-bonded by the pressure-bonding roller 3 is sent to the hot plate 4 and held in a heated state to cause an alloying reaction.

The surface temperature of the hot plate at this time is not lower than the melting point of lithium, preferably 300 to 500 ° C.,
In any case, 700 ℃ required when the melting method is used
Alloys are obtained at temperatures well below.

The alloyed foil is crushed by a crush roller 5. Since the alloy foil is thin and has a large surface area, unlike the case of casting a molten alloy, the temperature immediately drops, so that the alloy foil can be crushed without a cooling step.

The crushed lithium-aluminum alloy is put into the crusher 6 as it is, further pulverized, and collected in the pan 7.

The unalloyed aluminum portion is wound up by the winding roller 8 as it is.

[0021]

As described above, according to the present invention, the lithium-aluminum alloy powder can be continuously produced with a small amount of energy and a small facility, and the material loss is small, and the segregation like the melting method is used. Since it does not occur, the components are uniform and a high quality lithium-aluminum alloy powder can be provided at low cost. Therefore, it can contribute to the development of various high performance batteries, and its industrial value is great.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a manufacturing apparatus for carrying out a method for manufacturing a lithium-aluminum alloy powder according to the present invention.

[Explanation of symbols]

1 ... Lithium foil 2 ... Aluminum foil 3 ... Crimping roller 4 ... Hot plate 5 ... Crash roller 6 ... Crusher 8 ... Winding roller

Claims (2)

[Claims] 1. A method for producing a lithium-aluminum alloy powder, which comprises press-bonding and heating an aluminum foil and a lithium foil in an inert atmosphere to form an alloy and pulverizing. 2. A step of feeding a lithium foil and an aluminum foil wider than the lithium foil between pressure-bonding rollers to perform pressure bonding, a step of holding the pressure-bonded object in a heated state at a temperature equal to or higher than the melting point of lithium to alloy it. A method for producing a lithium-aluminum alloy powder, which comprises a step of crushing an alloyed foil and a step of winding the remaining aluminum portion.