JPS6243306B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to an improvement in the manufacturing method of a non-aqueous electrolyte battery that uses an anode formed by integrally press-molding a metal mesh and an anode mixture, by correcting the warping of the anode that occurs during pressure-forming, and The purpose is to prevent sealing defects during battery manufacturing. As battery application devices become thinner, battery anodes are also required to become thinner and thinner, but thinner anodes are more likely to crack during pressure molding.
The anode mixture is reinforced with a metal mesh such as wire mesh or expanded metal. An anode reinforced with such a metal mesh is usually produced by filling the anode mixture powder into a predetermined mold, placing the metal mesh on top of the mold, and press-molding it, or by filling the anode mixture powder into a mold. After preforming, a metal mesh is placed on top of the preform and pressure molded. However, when the anode is taken out of the mold, the anode mixture part of the anode does not move in the radial or thickness direction. This causes a so-called springback phenomenon in which the material tries to stretch. In this case, on the side where the metal mesh is attached, the radially outward stretching force is stopped by the metal mesh, so as shown in FIG. Warpage occurs. If a battery is manufactured using such a warped anode, the anode may crack when the battery is sealed, or the anode may shift from its designated position, causing the periphery of the anode to become stuck between the anode can and the annular gasket. Poor sealing occurs, such as when the seal is stuck in place. Therefore, by heat-treating the anode, a kind of annealing effect is applied to the metal network, modifying the constituent metals of the metal network to have low spring elasticity and easy plastic deformation, thereby correcting the warpage of the anode. A method has been discovered and a patent application has already been filed by the applicant; however, when a large number of anodes are heat-treated to the extent suitable for industrial production, the anodes partially overlap each other. As a result, there is a difference in the degree of warpage correction between the part where the other anode is placed and the part where it is not, which makes the anode even more unfavorable than before the heat treatment. As a result of further research, the inventor found that rather than carefully heat treating the anodes while preventing their partial overlap, the inventors actively stacked the anodes and left them in that state. It was discovered that heat treatment not only does not cause the above-described deformation of the anode but also corrects the warpage more uniformly, leading to the completion of this invention. That is, when manufacturing a non-aqueous electrolyte battery using an anode formed by integrally press-forming a metal mesh and an anode mixture, the present invention is able to produce a , relates to a method for manufacturing a non-aqueous electrolyte battery characterized by correcting warpage of an anode that occurs during pressure molding. When carrying out this invention, in order to stack anodes horizontally, a heat-resistant cylinder made of metal, ceramic, or the like having an inner diameter slightly larger than the outer diameter of the anode is used, and about 100 to 200 anodes are stacked in the cylinder. Preferably, this is carried out by. However, in this invention, horizontal does not mean only true horizontality, but also includes a nearly horizontal state. In this invention, it is necessary to select the temperature during the heat treatment of the anode within a range that gives an annealing effect to the metal network and does not adversely affect the activity of the anode active material. From this point of view, the lower limit temperature during heat treatment is approximately 300℃.
It is preferable to adopt the upper limit temperature, and it is desirable to determine the upper limit temperature according to the type of anode active material. For example, if the anode active material is manganese dioxide, about 450°C, if iron sulfide, about 800°C, In the case of cuprous sulfide, the temperature is preferably about 600°C. Although the treatment time varies depending on the treatment temperature, it is usually 30 minutes to 4 hours. In this invention, a wire mesh or an expanded metal is used as the metal net, and the material used is stainless steel or nickel. And in the case of wire mesh, the wire diameter is 0.05 to 0.12mm.
It is preferable to use a material with a diameter of 15 to 100 meshes, and in the case of expanded metal, a material with a thickness of 0.10 to 0.35 mm and an aperture ratio of 55 to 85% by area is preferred. The anode mixture includes manganese dioxide, iron sulfide,
A material consisting of anode active materials such as copper sulfide, copper oxide, carbon fluoride, and silver chromate, a conductive agent such as phosphorous graphite, and a binder such as polytetrafluoroethylene is used, and the pressure during pressure molding is Generally, 1 to 5 t/cm ² , preferably around 3 t/cm ² is adopted. Furthermore, light metals such as lithium, sodium, and magnesium are used as the cathode active material. FIG. 1 shows an example of the structure of a non-aqueous electrolyte battery manufactured by the method of the present invention. The anodes are stacked in a cylinder and heat-treated in that state; 4 is stainless steel;
The anode can is made of a metal plate such as nickel or stainless-nickel, and the anode 1 is housed in the anode can 4 with its metal mesh 2 side in contact with the bottom of the anode can 4. Reference numeral 5 denotes a disc-shaped cathode material made of metallic lithium, and this cathode material 5 includes a wire mesh 7 made of nickel or stainless steel that is spot-welded to the inner surface of a cathode can 6 made of the same metal plate as the anode can 4. is crimped to. 8 is a separator made of non-woven fabric such as polyethylene, polypropylene, glass fiber, etc. placed between the anode 1 and the cathode agent 5, and 9 is interposed between the opening of the anode can 4 and the cathode can 6. An annular gasket made of polyethylene, polypropylene, nylon, etc. In this battery, for example, 1,2-dimethoxyethane, propylene carbonate, tetrahydrofuran, γ-butyrolactone, etc. may be used alone or in combination.
A non-aqueous electrolyte made by dissolving lithium perchlorate or lithium borofluoride in a mixed solvent of more than one species is injected. Table 1 below shows the difference in the state of correction of anode warpage when 1000 anodes were heat treated by method A of the present invention and method B for comparison, which will be described later. . The anode used was 100 parts of manganese dioxide (parts by weight, the same applies hereinafter) and phosphorous graphite.
After preforming an anode mixture powder consisting of 10 parts and 1.7 parts of polytetrafluoroethylene at 1 t/cm ² , it was integrally press-formed with a stainless steel mesh with a wire diameter of 0.08 mmφ and a mesh size of 60 mesh at 3 t/cm ² . It is a thing,
The design dimensions of this anode are diameter 15.7mmφ and thickness 0.51mm.
It is.

[Table] Method A of this invention uses an anode with an inner diameter of 16 mmφ and an outer diameter of 30 mm.
Method B involves stacking 100 anodes in a ceramic cylinder with a diameter of 1300 mm and heating them at 400°C for 4 hours. This method involves heat treatment at 400°C for 4 hours. The warpage shown in Table 1 is expressed as h-t when the anode 1 is placed horizontally as shown in Figure 2, where h is the total height of the anode and t is the thickness. . As shown in Table 1, when using method A of the present invention, the warpage of the anode is smaller than when using method B, and in most cases, the warpage is 0.08 mm or less, which is considered desirable for battery manufacturing. become. Table 2 consists of the configuration shown in Figure 1, and includes battery A using an anode heat-treated by method A, battery B using an anode heat-treated by method B, and battery B that was not heat-treated. In addition, battery C using the same anode as battery A was used.
This shows the results of investigating the number of sealing failures when 1000 pieces were manufactured. The design dimensions of these batteries are 20 mm in diameter and 1.6 mm in height.

[Table] As shown in Table 2, in the case of battery A manufactured by the method of the present invention, the number of sealing failures was small. As described in detail above, the present invention involves heating the anodes in a horizontally stacked state when manufacturing a non-aqueous electrolyte battery using an anode formed by integrally press-molding a metal mesh and an anode mixture. By performing the treatment, the warpage of the anode that occurred during pressure molding is corrected, and
This is to prevent sealing failures caused by warping of the anode.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the structure of a non-aqueous electrolyte battery manufactured by the method of the present invention, and FIG. 2 is a sectional view showing a state where the anode is warped. 1...Anode, 2...Metal network, 3...Anode mixture.

Claims (1)

[Claims] 1. When manufacturing a non-aqueous electrolyte battery that uses an anode formed by integrally press-molding a metal mesh and an anode mixture, the anodes are stacked horizontally and subjected to heat treatment. A method for manufacturing a non-aqueous electrolyte battery, which is characterized by correcting warpage of an anode that sometimes occurs.