JPS62139265A - Cylindrical lithium battery - Google Patents

Abstract

PURPOSE:To obtain a cylindrical lithium battery whose workability and high rate discharge performance are improved by extruding upward a positive core material from a spiral electrode plate, and arranging a conductor obtained by filling a metal nonwoven fabric in a cylindrical sealing frame battery the extruded core material and a positive terminal to electrically connect them. CONSTITUTION:After forming a spiral electrode group, it is inserted into a nickel plate steel battery case 8 so that a lead plate 6 of negative lithium comes in contact with the inner bottom of the case via a hole-installed insulating bottom plate 7, and spot-welded to the case 8 by utilizing the center space of the electrode group formed by removing a center rod for winding. an upper insulating ring 9 is arranged, and a groove 8' is formed in the case 8. After pouring a specified amount of electrolyte, a metal nonwoven fabric 10 made of stainless steel fiber is arranged, then a cylindrical sealing frame 11 is arranged to prevent short circuit caused by contact of groove 8' to the positive core metal 2 or the nonwoven fabric 10. A sealing plate 13 also serving as gasket having a positive terminal plate 12 is placed on the nonwoven fabric 10, then a battery is sealed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to electrical connection between a positive electrode and a positive terminal plate in a cylindrical lithium battery used as a power source for small electronic devices related to electronics.

Conventional technology Conventionally, this type of cylindrical lithium battery has an electrode group structure in which a sheet-shaped positive electrode and a negative electrode are spirally wound through a separator in order to extract as large a discharge current as possible, and the reaction area of the positive and negative electrode plates is reduced. There is something bigger. Electrical connection between the positive electrode plate and the positive terminal plate of this type of battery is achieved by peeling off a portion of the positive electrode mixture in the two width directions of the positive electrode and welding the lead plate to the exposed core material. After winding the plate, it is welded to the terminal plate. Considering the workability of pouring the electrolyte, the lead plate must be welded to the positive terminal plate after pouring the electrolyte, but if a flammable organic solvent is used in the electrolyte, there is a risk of ignition. Must work in an inert gas atmosphere.

Additionally, due to the structure, the current path flowing from the end of the stop plate goes from the positive electrode core material, which is as thin as the length of the positive electrode plate, to the terminal plate via a thin lead plate, which increases resistance and makes it difficult to extract current. .

Problems to be Solved by the Invention As described above, in the conventional configuration, the positive electrode lead plate is welded to the positive electrode terminal plate of a cylindrical lithium battery configured in a spiral configuration using thin sheet-like electrode plates capable of high-rate discharge characteristics. The process was carried out in an inert gas atmosphere, resulting in poor workability, and the high resistance of the current path made it difficult to extract a large current.

The present invention solves all of these problems, and has 3 points and 7 points.
' The purpose is to improve the electrical connection between the positive electrode plate and the positive terminal plate.

Means for Solving the Problems In order to achieve the above object, the present invention has a positive electrode core protruding above the spiral electrode group, and a metal is inserted between the core and the positive terminal plate within a cylindrical sealing frame. It is made by electrically contacting a conductor filled with nonwoven fabric.

Effect When creating a current with this configuration, since there is no positive electrode lead plate, there is no need to weld the lead plate and the positive terminal plate, and an inert gas atmosphere is not required.
The current path between the end of the positive electrode plate and the positive terminal plate can also be shortened by using the conductor, and the high rate discharge characteristics, which is the main purpose of the electrode group in which the thin electrode plate is wound, can be improved.

Embodiment FIG. 1 shows a cylindrical MnO2/Li which is an embodiment of the present invention.
A cross-sectional view of the battery is shown, and FIG. 2 shows a developed structure of the positive electrode.

In the figure, 1 is the positive electrode, which is a mixture made by adding 2 parts by weight of carbon black as a conductive agent and 12 parts by weight of poly(4-fluoro-modified ethylene) as a binder to heat-treated MnO2 powder, adding water, and kneading them. It consists of a sheet-like electrode plate that is formed into a sheet with a rolling roller and then press-fitted into a porous positive electrode core material 2 made of stainless steel. In use, this electrode plate was first dried at 110°C and cut into a size with the electrode plate width 1 mm longer than the positive electrode in the conventional configuration, and then the length of the positive electrode was cut by 1 mm from one end in the width direction of the positive electrode plate. Peel off the mixture in the horizontal direction to make the positive electrode core material 2 protrude, then cover and insulate one end of the positive electrode plate in the length direction with adhesive Teflon tape 3 in a U-shape, and dry in a vacuum dryer at 26°C. Secondary drying is carried out for about 12 hours in a vacuum chamber for dehydration.

The end 1' of the positive electrode plate in the length direction where the tape is not stretched is the winding core side, and the negative electrode lithium 5 is opposed to the negative electrode lithium 5 through the microporous polypropylene separator 4 to form a spiral electrode. form a group.

After forming the electrode group, insert the negative electrode lithium lead plate 6 through the perforated bottom insulating plate so that it touches the inner bottom of the battery case 8, which is made of nickel-plated iron, and remove the core trace space in the center of the electrode group. Use this to spot weld.

After the electrode group is housed in the battery case 8 as described above, the upper insulating ring 9 is placed and a groove is made in the battery case. Next, after injecting a predetermined electrolytic solution, a metal nonwoven fabric 1o made of stainless steel fibers with an outer diameter of 12 mm is placed, and the grooved part of the battery case connected to the negative electrode and the exposed positive electrode core material 2 are placed. A cylindrical sealing frame 11 is arranged to prevent internal short-circuit failure due to contact with the metal nonwoven fabric 1Q, and a sealing plate/gasket 13 with a positive terminal plate 12 crimped thereon is arranged and sealed. The metal nonwoven fabric 1o comes into contact with the protruding core material 2 of the positive electrode and the lower surface of the positive electrode terminal plate 12 due to the tightening pressure.

The 2AA size battery produced as described above was compared with a battery having a conventional configuration.

The positive electrode used in the conventional structure is made by peeling off part of the positive electrode mixture in the width direction of the positive electrode and welding a lead plate to the core material, so the electrical connection between the positive electrode and the positive terminal plate is made after filling the positive electrode. The lead plate and positive terminal plate must be welded together for 6 pages. For this reason, the work must be performed in a sealed box filled with argon gas, and when inserting parts into the sealed box, part of the air must be replaced with argon, resulting in poor work efficiency. A large amount of argon gas is consumed during this process. On the other hand, in the structure according to the present invention, since welding is not necessary, the working atmosphere can be made of dry air. This has increased productivity by about five times compared to conventional methods and reduced expenses associated with argon gas consumption.

Furthermore, in the past, the current path flowing from the end of the positive electrode plate was from the positive electrode core material in the length direction of the positive electrode plate to the positive electrode terminal plate via a thin lead plate, making it difficult to extract the stain current with high resistance. In the configuration according to the present invention, the current path from the end of the positive electrode plate is also short and is formed from the protruding core material of the positive electrode plate at that portion via the metal nonwoven fabric, so that the resistance is reduced. As a result, the short circuit current increased from about 11 people to about 14A.

In addition, if an insulating cylindrical seal frame is not used, impact,
Internal short circuits are likely to occur due to vibration, etc., and after inserting the electrode group into the battery case and injecting liquid, we sealed it with only metal non-woven fabric without using a cylindrical sealing frame, resulting in approximately 100 cases. I had a fever. This is because the exposed positive electrode core material and metal nonwoven fabric came into contact with the grooved part of the battery case connected to the negative electrode, causing an internal short circuit.

On the other hand, such defects did not occur in the case where the cylindrical seal frame was arranged between the positive electrode core material, the metal nonwoven fabric, and the battery case.

Effects of the Invention As described above, the present invention improves the electrical connection structure between the core material protruding from the positive electrode of a cylindrical lithium battery having a spiral electrode group intended for high-rate discharge and the positive terminal plate. The present invention provides a cylindrical lithium battery that enables improved workability and high-rate discharge characteristics.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a cylindrical lithium battery according to an embodiment of the present invention, and FIG. 2 is a developed structural diagram of the same positive electrode plate. 1...Positive electrode, 2...Positive electrode core material, 4...
... Separator, 5 ... Lithium negative electrode, 1
o...Metal nonwoven fabric, 11...Cylindrical seal frame, 12...Positive terminal plate.

Claims (1)

[Claims] A cylindrical lithium lithium battery with a positive electrode core protruding above the spiral electrode group, and a conductor filled with metal non-woven fabric in a cylindrical seal frame being electrically abutted between the protruding core material and the positive electrode terminal. battery.