JPS59169059A - Production method of flat lithium cell with lead terminals - Google Patents

Abstract

PURPOSE:To increase the terminal strength by providing a spare terminal so as to cover a heat- insulating material provided at the center of the outer surface of a negative electrode terminal plate, spot-welding the periphery of the spare terminal to the negative electrode terminal plate, and welding a lead terminal of the negative electrode to the spare terminal surface at the portion corresponding to the heat-insulating material. CONSTITUTION:A positive electrode 5 is stored in a positive electrode can 7 and is faced to a negative electrode 9 through a separator 8. The negative electrode 9 is constituted by inserting disk-like metal lithium and pressing it into contact with a negative electrode terminal plate 4. An electrolyte is filled inside the positive electrode can 7 and terminal plate 4 and they are sealed by an annular gasket 11. A heat-insulating material 1 is arranged at the center of the outer surface side of the terminal plate 4, a spare terminal 2 made of a thin metal plate is arranged so as to cover the heat-insulating material 1, and the periphery of the terminal 2 is spot-welded to the terminal plate 4. Next, a lead terminal 3 with its tip compressed flat is brought into contact and spot-welded to the terminal 2, at the portion corresponding to the heat-insulating material 1. Corresponding to the heat-insulating material 1. And a lead terminal 13 is directly welded to the outer surface of the positive electrode can 7. Accordingly, an internal short circuit of a cell can be prevented and the welding strength of lead wires can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the manufacturing method of a flat lithium battery with a lead terminal, and prior to welding the lead terminal on the negative electrode side, a spare terminal for welding the -F terminal is attached to the negative electrode terminal plate. The purpose is to make it possible to firmly attach a strong lead terminal without deteriorating battery performance by performing spot welding with a heat insulating material interposed in the center.

Because lithium batteries have excellent storage characteristics, they have recently been increasingly used as backup power sources for electrical equipment. In such applications, originally,
Since the battery is not replaced during the life of the device, the battery is integrated into the device by fixing the battery to the device's circuit board by soldering or the like. Therefore, it is necessary to attach lead terminals to the battery in advance to facilitate soldering.

By the way, in the past, this lead terminal was attached by spot welding the lead terminal directly to the negative terminal plate or positive electrode can as a battery terminal, but the lithium used in the negative electrode was heated at about 186°C. Because it is molten, when a large amount of heat is applied to the negative terminal plate, the lithium melts and becomes thinner.

In the pond, molten lithium passes through the separator and causes an internal short circuit, so large amounts of energy cannot be applied to the negative terminal plate, and as a result, the welding strength on the negative electrode side tends to be low.

Further, due to the above-mentioned reasons, there are restrictions on the lead terminals that can be attached, and it has been impossible to attach lead terminals that are thick and strong.

The present invention solves the above-mentioned drawbacks of the prior art. Prior to attaching the lead terminal on the negative electrode side, a heat insulating material is placed in the center of the outer surface of a single-pole terminal containing a lithium negative electrode, and Place a spare terminal made of thin metal sheet to cover the heat insulating material, spot weld its periphery to the negative terminal plate, and spot weld the lead terminal on the negative side to the surface of the spare terminal corresponding to the heat insulating material. By doing so, it is possible to securely attach a strong lead terminal without causing a deterioration in battery characteristics.

Next, embodiments of the present invention will be described with reference to the drawings.

Figure 1 shows the insulation material, spare terminal, and IJ-F terminal before being attached to the negative terminal plate. (1) is the insulation material, and this insulation material (1) has a thickness Q, j)vl, and a diameter 101f
Potash than glass fiber nonwoven fabric of f, (2) has thickness Q, lW
This is a spare terminal made of a nickel disk with a diameter of 14 mm. (3) is a lead terminal made by compressing one end of a nickel wire with a diameter of 0.7 fi into a flat shape with a thickness of 0.8 mm so that spot welding can be easily performed.

Figure 2 shows a flat lithium battery to which lead terminals are attached. In the figure, (4) is attached to the insulation material (1), spare terminal (2) and lead terminal (3) shown in Figure 1. (5) is a negative electrode terminal plate made of a nickel-stainless steel clad plate.(5) is a mixture powder consisting of 100 parts of manganese dioxide (parts by weight, the same applies hereinafter), 10 parts of phosphorous graphite, and 2 parts of polytetrafluoroethylene. The positive electrode is pressure-formed, and (6) is a stainless steel mesh that serves as a current collector for the positive electrode (5). (7) is a positive electrode can made of a nickel-stainless steel clad plate, with the stainless steel side facing the battery. Arranged on the inside, 1 (8) is a separator made of polypropylene nonwoven fabric, and (9) is a lithium negative electrode.
) and is crimped onto a stainless steel net QQ spot-welded to the inner surface of the negative terminal plate (4).

The α force is a polypropylene annular gasket, and the electrolyte for this battery contains 0.5 mol/l of lithium perchlorate in a mixed solvent of propylene carbonate and 1,2-dimethoxyethane with a volume ratio of 2:1. It is used dissolved. (2) is a heat-shrinkable vinyl chloride resin tube that is placed over the outer periphery of the battery.This is to prevent a short circuit between the negative electrode side lead terminal and the positive electrode can (7), which will be attached later. .

The negative electrode lead terminal is attached to the battery in the following manner. ' First, place the heat insulating material (1) approximately at the center of the outer surface of the negative terminal plate (4), and place the spare terminal (2) on top of it so as to cover the heat insulating material (1). . and insulation (
The peripheral edge of the spare terminal (2) where 1) is not interposed is spot-welded to the negative electrode terminal 1fi (4). Spot welding points are usually taken at four locations equally spaced in the circumferential direction.

When spot welding this spare terminal (2),
The lead terminal (3) is thinner than the lead terminal (3), so it does not require much energy for welding, and the area is wider than the lead terminal (3), so the spot welding points can be spaced apart. (3) is less affected by heat on the lithium negative electrode (9) than when welding directly to the negative electrode terminal plate (4). Next, the flat compressed tip of the IJ-)' terminal (3) made of the nickel wire is brought into contact with this preliminary terminal (2) and spot welded. The welding point is the heat insulating material (1
) is the position corresponding to the intervening part. This welding requires higher energy than when welding the preliminary terminal (2), but compared to welding the lead terminal (3) directly to the negative terminal plate (4), the distance from the welding point to the lithium negative electrode (9) is Due to the long distance between the preliminary terminal (2) and the heat insulating material (1) and the heat insulating effect of the heat insulating material (1), the heat transferred to the lithium negative electrode (9) is at least slightly reduced by the melting of lithium. is suppressed, and the occurrence of internal short circuits is prevented. Therefore, high energy can be applied to welding the lead terminal on the negative electrode side, allowing the thick and strong lead terminal to be firmly attached.

On the positive electrode side, a lead terminal (to) having the same shape as the lead terminal (3) on the negative electrode side is spot welded to the outer surface of the positive electrode can (7), and the lead terminals (3), ( To)
A flat lithium negative electrode is formed. Furthermore, on the positive electrode side, the positive electrode (5) is not affected too much by the heat used to spot weld the positive IJ-de terminal (to), so a spare terminal is not particularly required.

In the present invention, examples of the heat insulating material include ceramics,
Asbestos board, mica, silica, glass fiber, etc. are used.

Preferably, the preliminary terminal (2) is, for example, a stainless steel plate, a nickel plate, or an iron plate plated with nickel or tin, and its thickness is preferably about 0.01 to 0.2 mm.

Lead terminal on the negative side (3), lead terminal on the positive side (to)
For example, nickel wire, nickel-plated or tin-plated iron wire, or stainless steel wire with a diameter of 0.7~
1.0 mm, and the tip portion to be subjected to spot welding has a thickness of 0.0 mm.
It is preferable to use a material that has been pressed to about 8 mm and compressed into a flat shape.

The following Table 1 shows the results of investigating the number of batteries in which internal short circuits occurred when the lead terminal was spot-welded directly to the negative terminal plate using the conventional method in the case of the present invention as described above. Battery (20M in diameter, height)
Height up to the top of the negative terminal plate (4), excluding the insulation material (1), spare terminal (2), negative terminal (3), and lead terminal (to) on the positive terminal) 3.2ff
In the case of the present invention, as described above, the negative terminal plate (4)
A heat insulating material (1) made of glass fiber non-woven fabric with a diameter Log and a thickness of 0.2M is interposed on the outer surface side of the
) should be spot welded, and the spot welding position should be the insulation material (1).
The number of lead terminals is 4 at the peripheral edge where there is no ) were spot welded. As shown in FIG. 3, there are two spot welding points α→ at positions corresponding to the portion where the heat insulating material (1) is interposed. In the case of the conventional method, as described above, a lead terminal made of a nickel wire similar to that described above was spot-welded directly to the negative terminal plate.

The negative terminal plates of the batteries used were all 0.211 mm thick.
It is made from a 11 nickel-stainless steel rad plate, and a lithium plate with a diameter of 14 m and a thickness of 0.50 mm is used for the lithium negative electrode. As mentioned above, the lead terminal (3) is made of nickel, and the conditions for spot welding this lead terminal are stored energy of 40 W and S.

The current application time is 2 mS, the pressure is 2 kg, and the spot welding conditions for the preliminary terminal (2) in the present invention are stored energy t.
ow, s, energization time 2 mS, and pressing force 2 to 9. The number of batteries subjected to the test was 100 for both the method of the present invention and the conventional method.

Table 1 The lead terminals were spot welded under the same seven conditions as described above, but in the case of the present invention, as shown in Table 1, no internal short circuit occurred at all. Further, in the battery according to the present invention, the welding strength of the lead terminals was sufficient, and the lead terminals often peeled off.

Furthermore, according to the present invention, since the lead terminals (3) and (to) can be attached to a completely finished battery for general use, special care is required from the time of battery manufacture to attach the lead terminals. There are no restrictions on specifications, and the batteries themselves can be used for general purposes, so they have great practical value.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a heat insulating material, a spare terminal, and a lead terminal before being attached to a negative terminal plate, and FIG. 2 is a sectional view showing a flat lithium battery. FIG. 8 is a sectional view showing an example of a flat lithium battery with lead terminals manufactured by the method of the present invention.

Claims (1)

[Claims] 1. In manufacturing a flat lithium battery with lead terminals in which lead terminals for extracting electricity are attached to the battery by welding, a heat insulating material is added to the outer surface of the negative terminal plate containing the lithium negative electrode. is placed in the center, a spare terminal made of a thin metal plate is placed so as to cover the heat insulating material, and a negative electrode terminal 1iK spot weld is applied to the peripheral edge of the spare terminal, and a spare terminal is placed in the area corresponding to the heat insulating material. A method for manufacturing a flat lithium battery with a lead terminal, which is characterized by welding a negative electrode side lead terminal to the surface. 2. The part of the lead terminal to be welded is flat,
The method for manufacturing a flat lithium battery with lead terminals according to claim 1, wherein the main body portion has a circular cross section.