JPH0745102B2 - Lithium thin film material and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a lithium thin film material that can be used for, for example, a lithium electrode and a method for producing the same.

[Prior Art] A conventional lithium thin film is manufactured by mechanical processing such as extrusion and rolling. For example, Japanese Examined Patent Publication No. 55-122 discloses a method for producing a relatively thin lithium strip having a thickness of about 40 .mu. By reducing the thickness of cold rolling lithium between the surfaces of a solid polymer composition. Japanese Patent Publication 55-4184
No. 1 discloses a method in which a metal foil is passed through a gap between a pair of rollers together with a plastic belt and rolled.

[Problems to be solved] However, according to the conventional manufacturing method by rolling, extrusion, etc., a very thin lithium thin film of, for example, 100 μ or less can be obtained. However, the obtained thin film has various mechanical characteristics peculiar to lithium. As a result, it is very easily deformed, and the tensile strength is not sufficient. Therefore, there are problems such as easy breakage, which makes handling extremely difficult. Further, in metals containing lithium, for example, in alloys such as Li-Al and Li-Mg,
Since alloys with Al and Mg contents such as 30w% and 40w% are thought to be able to prolong the service life of secondary batteries, thin film or precision molded products can be used as secondary battery materials. Although it is desired to provide such alloys, it is practically impossible to process the desired size and shape because the hardness and viscosity of the alloys with such contents increase and brittleness occurs. In particular, it has been an obstacle to research and development of lithium secondary batteries and commercialization.

The object of the present invention is that the workability is good and accurate dimensions can be obtained at low cost while considering various mechanical characteristics peculiar to lithium and a metal containing lithium, and in particular, conventional processing was virtually impossible. It is intended to provide a method for producing a lithium thin film and a product thereof for a metal containing lithium.

[Means for Solving the Problems] As a result of earnest studies to achieve the above object, as a result, the viscosity, the fluidity of lithium and a metal containing lithium at high temperature,
Utilizing the leakage property, lithium or a metal containing lithium is supported in the open pores of a thin film porous carrier made of a metal or a heat-resistant inorganic material, and a lithium thin film of a desired thickness regulated by the dimensions of the open pores is made into lithium. We have developed a manufacturing method for obtaining thin film materials. That is, a thin-film porous carrier made of a metal or a heat-resistant inorganic material and a thin-film lithium carrier made of a thin-film lithium or a metal containing lithium supported in the pores of the porous carrier were developed.

[Operation] Therefore, according to the present invention, since lithium or a metal containing lithium is supported in the open pores of the thin film-like porous carrier, mechanical processing such as rolling is conventionally performed when thinning lithium. Since there is no deformation, there is no deformation or breakage, workability is extremely good, and metal containing lithium with a large content of Al, Mg, etc., which was conventionally difficult or impossible to form, can be thinned. There are extraordinary advantages that can be easily made. Moreover, since the size of the lithium thin film to be supported is regulated by the size of the opening of the thin film porous carrier, it is possible to obtain a lithium thin film having a desired thickness with an accurate size by appropriately selecting the size of the opening. it can.

Further, in supporting lithium or a metal containing lithium in the openings of the thin film porous carrier, since a molten metal of lithium or a metal containing lithium is fed into the openings of the thin film porous carrier having a low temperature. Since the whole solidifies uniformly within a short period of time, especially in the case of metal containing lithium, the molten metal is poured into a mold once and then the molten metal is gradually cooled to solidify the molten metal to obtain a lump, followed by rolling, extrusion, etc. It is possible to prevent the deviation of the component called segregation that occurs due to the difference in specific gravity between lithium and other metals inside the lump that often occurs during processing, and it is also possible to obtain a thin metal film containing lithium that is homogeneous throughout. .

The lithium thin film is supported in the open pores of the thin film-like porous carrier, and is obtained as a lithium thin film material, so that it is possible to easily increase the size of the product by appropriately selecting the size of the thin film-like porous carrier, and Since this lithium thin film material can be used as it is as a current collector, in that case, there is an advantage that steps can be omitted at the time of battery production.

Further, according to the present invention, since a rolling device and an extruding device are not required, a large-scale device is not required even in mass production or manufacturing of large-sized products, and initial investment and running cost are low.

[Embodiment] FIG. 1 is a schematic view for explaining an embodiment of the present invention.

Reference numeral 1 denotes a strip-shaped thin film porous carrier made of a metal material, and is arranged so as to be fed from a winding roller 2 and wound by a winding roller 3 as shown in the figure. Reference numeral 4 is a supply container for lithium or a metal 5 containing lithium arranged at an intermediate position thereof. The supply container 4 is provided with a heater 6 for supplying lithium or a metal containing lithium to the thin film porous carrier 1 in a molten state, and the opening of the thin film porous carrier 1 while avoiding excessive melting. In order to make the supply to the parts smooth, the inert gas 7 such as Ar can pressurize the lithium or the metal 5 containing lithium as needed. A roller 8 is arranged on the opposite side of the supply container 4 with the thin film-like porous carrier 1 interposed therebetween to ensure that lithium or a metal 5 containing lithium is supported in the opening of the porous carrier 1. There is. In addition, 9 is a roller, 10 and 11 are spatula, and 12 is a stirring propeller provided in the supply container.

Therefore, the thin film porous carrier 1 fed from the unwinding roller 2 is supplied with lithium or the metal 5 containing lithium in a molten state on the roller 8, and the lithium or the metal 5 containing lithium is thin film porous. It is fed into the open pores of the carrier 1, uniformly coagulated by the thin film porous carrier 1 having a low temperature, and carried in the open pores of the thin film porous carrier 1. Then, after passing through the roller 9 and the spatula 10 and 11, it is wound up by the winding roller 3.

Second, a lithium thin film obtained by this method, comprising a thin film porous carrier 1 made of a metal material, and thin film lithium or a metal 14 containing lithium supported in the pores 13 of the porous carrier 1. It is sectional drawing of a material.

FIG. 3 is a schematic view for explaining another embodiment of the present invention.
In this embodiment, unlike the above-mentioned embodiment, the strip-shaped thin film porous carrier 1 is passed through a tank 15 of lithium or a metal 5 containing lithium which is heated and melted by a heater 6 so that the porous carrier 1 contains lithium or lithium. A method in which the metal 5 containing lithium is impregnated in a state of being impregnated into the hole is adopted.

Therefore, the thin film porous carrier 1 fed from the unwinding roller 2 is a tank 15 of lithium or a metal 5 containing lithium.
The lithium or the metal 5 containing lithium which is in a molten state on the roller 8 is supplied into the opening while passing through the inside, and the lithium or the metal 5 containing lithium is supplied into the opening of the thin film porous carrier 1. Then, it is uniformly solidified outside the tank 15 and is carried in the opening portion of the thin film porous carrier 1. In the same manner as in the above-mentioned embodiment, reference numeral 9 is a roller, 10 and 11 are spatula, 1
Reference numeral 2 is a stirring propeller provided in the tank 15.

The present invention is not limited to the above embodiment. For example, in the above-mentioned embodiment, the strip-shaped thin film porous carrier 1 is used for continuous production, but a single-piece thin film porous carrier may be used discontinuously. The material is not limited to metals such as stainless steel, nickel and copper, but a thin film porous carrier made of a heat-resistant inorganic material such as a ceramic material can be used. It is easy to use a so-called screen material such as a mesh or expanded metal as the thin film porous carrier, but the screen material itself is not particularly limited. In short, it does not matter as long as it is a thin film-like porous carrier in which a molten metal of lithium or a metal containing lithium is fed and carried in the opening portion.

In supporting lithium or a metal containing lithium in the openings of the thin film-like porous carrier, even if the metal containing lithium or lithium is heated and melted at an excessively high temperature,
On the contrary, melting at a temperature too low is not preferable. This is because if the temperature is too high, the solidification rate in the openings of lithium or a metal containing lithium does not follow up, and the hot water of the metal containing lithium or lithium tends to drop out from the openings of the porous carrier. This is because if the temperature is too low, it becomes difficult to feed into the opening and solidifies immediately so that a uniform lithium thin film cannot be obtained. Therefore, it is desirable that the molten state is such that it can be fed into the opening portion and has a holding force that does not flow down in the opening portion, exhibiting viscosity, fluidity and wetting characteristics. In this sense
In addition to these, it is preferable to control the temperature of the porous carrier to lower the temperature in order to favorably support it in the opening. It is also important to consider the size of the pore size, etc., and make a selection in consideration of various properties such as viscosity of various lithium or metals containing lithium while considering properties and applications expected of lithium thin film materials. Is desirable. In order to accelerate the feeding of the porous carrier into the opening, vibration can be forcibly applied separately. Further, when the continuous strip method is adopted as in the above embodiment, it is important to further consider the traveling speed of the porous carrier and the like. In any case, it suffices to set various conditions in consideration of various factors according to the difference in various characteristics of lithium or a metal containing lithium.

The lithium thin film material is preferably obtained by the manufacturing method according to the above embodiment, but the manufacturing method is not particularly limited. In short, not the conventional lithium thin film itself, but a thin film-like porous carrier made of a metal or a heat-resistant inorganic material, and a thin film lithium material made of thin film lithium or a metal containing lithium supported in the opening of the porous carrier. Then all are applicable. Further, in the present invention, when the thin film-like porous carrier is made to carry lithium or a metal containing lithium, it is preferable to carry only the open pores, but it is also possible to make it adhere to the surface of the porous carrier itself.

[Effects of the Invention] As described above, the present invention has a configuration in which a lithium thin film is obtained as a lithium thin film material by supporting lithium or a metal containing lithium in the open pores of a thin film porous carrier such as a metal. It is possible to make lithium or a metal containing lithium into a thin film without mechanical processing such as direct rolling, and it does not deform or break as in the past,
It is possible to reproducibly produce a large amount of ultrathin lithium thin film with uniform and accurate dimensions without loss of raw materials. Therefore, for example, when the battery is manufactured, the handling is good, the workability is good, and the economical efficiency is exhibited. Moreover, it should be noted that since it is possible to obtain a lithium thin film even for a metal containing lithium with a high content of Al, Mg, etc., which has been virtually impossible to mechanically process in the past, a cathode characteristic is extremely superior to that of conventional ones. Batteries can also be provided, which is very large in contributing to the technical field.

[Brief description of drawings]

FIG. 1 is a schematic view for explaining an embodiment of the present invention, FIG. 2 is a partial sectional view of a lithium thin film material obtained by the same manufacturing method, and FIG.
The drawing is a schematic view for explaining another embodiment of the present invention. 1 ... Thin film porous carrier, 5 ... Lithium or metal containing lithium 13 ... Open hole, 14 ... Thin film lithium or metal containing lithium

Claims (2)

[Claims] 1. A molten metal of lithium or a metal containing lithium is charged and solidified in the opening portion of a thin film porous carrier made of a metal or a heat-resistant inorganic material to have a desired thickness regulated by the dimension of the opening portion. A method for producing a lithium thin film material, which comprises supporting a lithium thin film on a thin film-like porous carrier. 2. A lithium thin film material comprising a thin film porous carrier made of a metal or a heat resistant inorganic material, and thin film lithium or a metal containing lithium supported in an opening of the porous carrier.