JPH0560227B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to an improvement in a method for manufacturing a non-aqueous solvent battery. [Technical background of the invention and its problems] In recent years, lithium-thionyl chloride-based non-aqueous solvent batteries have attracted attention as batteries with high energy density and excellent long-term storage characteristics. The most important feature of such a battery is the use of a liquid oxyhalide such as thionyl chloride as the positive electrode active material, and the battery reaction proceeds by electrochemical reduction of the active material on the porous positive electrode surface. By the way, in a conventional battery, a negative electrode and a positive electrode are housed in a case (can body) with a separator interposed therebetween, and after storing an electrolyte in the can body, a cover (lid body) is attached to the upper opening of the can body using a rubber elastic material. A method of airtight sealing via an organic insulating material having . However, when the above-mentioned non-aqueous solvent battery is manufactured by such a method, the liquid oxyhalide such as thionyl chloride in the electrolytic solution is a highly irritating substance that easily gasifies, so the lid body does not arrive at the can body. There was a problem with the electrolyte evaporating during the previous steps. In addition, if the seal between the can body and the lid is insufficient and even a slight leak occurs, thionyl chloride will quickly react with moisture in the air, producing a corrosive gas with a pungent odor, and causing damage to the batteries. There was a problem with equipment damage. For this reason, in most cases, in lithium-thionyl chloride batteries, the negative and positive electrodes are housed in a can with a separator interposed between them, and a lid is hermetically sealed in the upper opening of the can by laser welding. After arriving,
The electrolyte is injected through a liquid injection port opened in the can body or lid, and the liquid injection port is sealed by laser welding or the like, thereby creating a completely sealed structure that prevents liquid leakage. Recently, in order to inject the electrolyte and seal the injection port, the positive terminal of the battery is shaped into a pipe and inserted into the lid via an insulating sealant, and after the electrolyte is injected into the can from this pipe, A method of sealing the pipe by laser welding or the like has been adopted. However, when the metal pipe is sealed by laser welding or the like after the electrolyte is injected, there is a drawback that sealing failures occur due to scattering, spouting, etc. of the electrolyte. [Object of the Invention] The present invention aims to provide a method for manufacturing a non-aqueous solvent battery that reduces sealing defects of metal pipes into which electrolyte is injected. [Summary of the Invention] The present inventors injected an electrolytic solution containing an oxyhalide as a positive electrode active material into the can through a metal pipe that also serves as a positive electrode terminal inserted into the lid, and then welded the pipe by laser welding or the like. As a result of various studies on sealing failures during sealing, we found that the metal pipe was connected to the positive metal current collector housed inside the can via a lead wire, and the pipe had a considerable length inside the can. Since the lower end of the pipe is immersed in the electrolyte inside the can, the pressure inside the can increases due to the heat generated during welding such as laser welding, and the electrolyte may spurt out of the pipe or cause damage to the inside of the pipe due to capillary action. It was discovered that sealing failures occur due to the electrolyte that had accumulated in the tubes scattering. Based on the above research results, the present inventors have determined that by lowering the level of the electrolyte contained in the can below the level of the lower end of the metal pipe, the metal pipe will become free from the electrolyte spout passage and pool. We have discovered a method for manufacturing a non-aqueous solvent battery with a completely airtight structure that avoids sealing defects caused by spouting or scattering of electrolyte during pipe welding. That is, the present invention accommodates a negative electrode made of an alkali metal and a positive electrode made of a porous carbon body and a metal current collector in a can via a separator, and furthermore, a lid is airtightly attached to the upper opening of the can. After that, an electrolytic solution mainly composed of oxyhalide, which also serves as a positive electrode active material, is injected into the can body from a metal pipe that is inserted into the can body and also serves as a positive electrode terminal, and then the pipe is welded. The method for manufacturing a sealed non-aqueous solvent battery is characterized in that the electrolyte is contained at a level lower than the lower end of the metal pipe inside the can body. [Embodiments of the Invention] Next, embodiments of the present invention will be described with reference to the drawings. Example First, the outer diameter 14 which doubles as a negative electrode terminal with an open top surface
A stainless steel can body 1 with a height of 47 mm and a thickness of 0.3 mm was prepared. Subsequently, a cylindrical negative electrode 2 made of metallic lithium and having a thickness of 0.7 mm was crimped onto the inside of the can 1. Next, the positive electrode 3 was housed inside the negative electrode 2 in the can body 1 with a cage-shaped separator 4 made of glass nonwoven fabric interposed therebetween. This positive electrode 3 is made by mixing a dispersion of polytetrafluoroethylene (binder) in an amount of 10% by weight with acetylene black, kneading,
After molding, dry outer diameter 12 mm, inner diameter 5 mm, height
It was manufactured by embedding a cylindrical metal current collector 6 made of expanded metal made of nickel in the inner peripheral surface of a 40 mm cylindrical porous carbon body 5. Next, insulating paper 7 is placed inside the can body 1 above the positive electrode 3 and the separator 4
It was placed by supporting it. Next, a metal top (lid) 11 is prepared, in which a stainless steel pipe 10 which also serves as a positive electrode terminal is inserted into the hole 8 in the center via a glass sealing material 9.
After the pipe 10 is connected via the nickel lead wire 12 of the metal current collector 6 of the positive electrode 3 housed in the can body 1, the metal top 11 is hermetically sealed to the upper opening of the can body by laser welding. did. Next, 3.5 ml of thionyl chloride solution (electrolyte) of 1.8M lithium aluminate tetrachloride (LiAlCl ₄ )
was injected into the can body 1 through the pipe 10, and the electrolytic solution 13 whose liquid level was lower than the lower end of the pipe 10 was housed in the can body 1. Subsequently, the sealing pin 14 is inserted into the stainless steel pipe 10, and the pipe 10 and the pin 14 are welded together by laser welding to complete the pipe 1.
A lithium-thionyl chloride battery was manufactured by sealing the battery. Comparative example: A metal top is sealed to the upper opening of the can, and 4.3 ml of a 1.8M thionyl chloride solution (electrolyte) of lithium tetrachloride aluminate is injected into the can through a stainless steel pipe. A lithium-thionyl chloride battery was manufactured in the same manner as in the example except that the electrolyte solution was placed at a level higher than the lower end of the pipe. However, by the methods of this example and comparative example,
When 1000 batteries were manufactured and the number of stainless steel pipe sealing failures was investigated using a helium-que detector for each battery, it was found that:
The results shown in the table below were obtained.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to provide a method for mass-producing a nonaqueous solvent battery having a good sealing structure that reduces sealing defects of a metal pipe for injecting an electrolytic solution.

[Brief explanation of drawings]

The figure is a cross-sectional view of a lithium-thionyl chloride battery manufactured according to an embodiment of the present invention. 1... Can body (negative electrode terminal), 2... Negative electrode, 3 ...
Positive electrode, 4... Separator, 10... Stainless steel pipe (positive electrode terminal), 11... Metal top (lid), 13... Electrolyte.

Claims (1)

[Claims] 1. A negative electrode made of an alkali metal and a positive electrode made of a porous carbon body and a metal current collector are housed in a can via a separator, and a lid is airtightly attached to the upper opening of the can. An electrolyte mainly composed of oxyhalide, which also serves as a positive electrode active material, is injected into the can body from a metal pipe that is inserted into the lid and also serves as a positive electrode terminal, and then stored therein, and the pipe is subsequently sealed by welding. A method for manufacturing a non-aqueous solvent battery, characterized in that the electrolytic solution is accommodated at a level lower than the lower end of the metal pipe inside the can body.