JPS63292567A - Manufacture of cell with lead terminal - Google Patents

Abstract

PURPOSE:To facilitate the positioning work at the time of welding and improve the reliability of the work by performing the laser welding with YAG double harmonic laser with the wavelength of 0.53 mum. CONSTITUTION:In producing a cell with lead terminal laser-welded with one end of a current extracting lead terminal 9 on the cell terminal face, the laser welding is performed with YAG double harmonic laser with the wavelength of 0.53mum. The wavelength of laser rays 10 is 0.53mum, thus an objective lens 7 with the double focal distance can be used to obtain the same spot diameter as that obtained with the wavelength of 1.06mum in the past. The divergent angle of the laser rays 10 radiated from the objective lens 7 to the cell 3 terminal face is made half, and the output change of the laser rays 10 by positions is decreased. The optimum welding range in the vertical direction is thereby expanded, not so high positioning precision is required, and the degree of dispersion of the welding strength due to displacement is reduced.

Description

[Detailed Description of the Invention] - <Industrial Application Field> The present invention relates to a method for manufacturing a battery with lead terminals, which is made by welding lead terminals for direct attachment to a printed circuit board, etc. to the terminal surface thereof. be.

<Prior art> The above-mentioned lead terminal-equipped battery is used as a backup power source for IC memory, etc. One end of the lead terminal made of is directly fixed by laser welding or the like, and the other end of the lead terminal is soldered to the terminal hole of the board, so that it can operate stably over a long period of time. When laser welding lead terminals in this way, normally one end of the lead terminal is placed in close contact with the battery terminal surface, and in this state a laser beam is applied from above to the welding point of the lead terminal. In the above laser welding, conventionally, a YAG laser that emits a laser beam with a wavelength of 1.06 μm is used, and a YAG laser that emits a laser beam with a wavelength of 1.06 μm is used.
Combined with an omm objective lens, this lens allows YA
The configuration is such that the laser light from the G laser is focused near the battery terminal surface.

<Problems to be Solved by the Invention> However, in the conventional method described above, for example, when the objective lens with the focal length ioomm is used, the optimal welding range in the vertical direction is approximately ±0.2 mm, which is very large. narrow. In this type of battery with lead terminals, for example, when a flat lithium battery is used, the thickness of the lead heir and/or battery terminal plate and battery can are all 0.3 mm.
Since the battery is quite thin, welding defects are likely to occur due to misalignment of the battery from the objective lens. Moreover, for this reason, extremely high positioning accuracy is required, and there is a problem in that there are large variations in welding strength.

<Means for Solving the Problems> A method for manufacturing a battery with a lead terminal according to the present invention is a method for manufacturing a battery with a lead terminal in which one end of a lead terminal for taking out current is laser welded to a battery terminal surface. The gist is that the laser welding was performed using a YAG double harmonic laser with a wavelength of 0.53 μm.

Further, in the laser welding described above, it is preferable to use a YAG double high frequency pulse laser because sufficient welding strength can be obtained without any thermal influence on the inside of the battery.

<Function> When the laser beam is focused on the legitimate surface of the battery using an objective lens with a focal length of F, the minimum spot diameter d is d=F.
It is expressed as θ...■ (θ is the opening angle of the light beam due to diffraction when the laser beam is sent as a light beam). Also, this opening angle θ
is θ-λ/b...■ (λ is the wavelength of the laser beam, b is the beam diameter), so from these formulas 1 and 2, the minimum spot diameter d=F·λ/b. The wavelength of the laser beam used in the present invention is 0.53 μm, compared to the conventional wavelength of 1.06 μm.
Therefore, when comparing the conventional method and the method of the present invention, the present invention uses an objective lens with twice the focal length (for example, 200 mm) to obtain the same spot diameter as the conventional method. be able to. If this objective lens is used, the spread angle of the laser beam irradiated from the objective lens toward the battery terminal surface is halved, and the change in output of the laser beam due to position is reduced.

As a result, the optimal welding range in the vertical direction is widened, positioning accuracy that is not so high as compared to the conventional method is required, and the degree of variation in welding strength due to positional deviation is reduced.

Further, when pulsed laser welding is used as the laser welding, for example, compared to a continuous wave type, a large output can be obtained in a short time, and sufficient welding strength can be obtained without the influence of heat on the inside.

<Example> An example in which the present invention is applied to a method of manufacturing a battery with lead terminals using a flat lithium battery will be described below.

In FIG. 1, 1 is a discharge tube, 2 is a YAG crystal, and 3 is a mirror, which constitute a laser oscillation section. The laser beam output from this laser oscillation section reaches a half mirror 5 after passing through a double harmonic element 4 made of Ba2 NaNb3 o15 (green element). In this half mirror 5, the wavelength of the laser beam is 1
．． The wavelength of 0.06 μm is reflected and removed, and the wavelength becomes 0.5 μm.
Only 3 μm laser light passes through. Next, this wavelength 0.
The 53 μm laser beam is directed downward in the figure by a reflector 6 and guided to an objective lens 7 located above a flat lithium battery 8 with a lead terminal 9 in close contact with its normal surface. The objective lens 7 focuses the light near the surface of the lead terminal 9. FIG. 2 shows the state in which the lead terminal 9 is welded to the negative terminal surface of the battery by this focused laser beam 10. In the figure, 11 is a battery can;
12 is a positive electrode mixture, 13 is a separator, 14 is a lithium negative electrode, 15 is a sealing gasket, and 16 is a terminal plate. In the example shown in FIG. 2, the laser beam 10 is focused slightly in front of the surface of the lead terminal 9 to minimize the thermal effect on the inside of the battery due to laser welding and to prevent a decrease in battery performance. This is to prevent it. And this laser beam 10
As a result, the welded portions of the lead terminals 9 and the terminal plate 16 are instantaneously heated and melted and welded together, and after irradiation with the laser beam 10, they are cooled and solidified to weld the two. Figure 3 shows a battery with lead terminals fabricated by such laser welding.
In this example, the lead terminal 9 is laser welded to the terminal plate 16 at two locations in its longitudinal direction.

In such a configuration, the lead terminal 9 is made of a nickel plate with a thickness of 0.2 mm, the terminal plate 16 is made of stainless steel with a thickness of 0.25 mm, and the objective lens 7 has a focal length of 200 mm. The optimum welding range in the vertical direction in the figure when using this method was ±0.4 mm.

On the other hand, when performing welding with a similar spot diameter using a laser beam with a wavelength of 1.06 μm as in the past, the focal length is 1.
It is necessary to use a 0.00 mm objective lens, and in that case, the optimal welding range in the vertical direction is ±0.2 mm, so by adopting the configuration of the present invention, the optimal welding range in the vertical direction is doubled, and the positioning It is clear that the welding is easier to remove and the variation in welding strength is reduced.

<Effects of the Invention> As described above, according to the manufacturing method of the present invention, the optimal welding range during laser welding becomes larger, making positioning during welding much easier, making the work easier, and improving the reliability of the work. It increases. Furthermore, since variations in welding strength are reduced, there are effects such as contributing to improving the reliability of the product itself.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the manufacturing method according to the embodiment of this invention, Fig. 2 is an explanatory diagram of the state in which the lead terminal is welded to the battery terminal surface, and Fig. 3 is an explanatory diagram of the battery with lead terminal manufactured by the method of the embodiment. FIG. 2...YAG crystal, 4...2nd harmonic element, 7...
・Objective lens, 8...Flat type lithium battery, 9...
Lead terminal, 10...laser light.

Claims (1)

[Claims] 1. In a method for manufacturing a battery with a lead terminal in which one end of a lead terminal for taking out current is laser welded to a battery terminal surface, the laser welding is performed using a YAG double harmonic laser with a wavelength of 0.53 μm. A method for manufacturing a battery with lead terminals characterized by the method carried out in . 2. The method according to claim 1, characterized in that Ba_2NaNb_5O_1_5 is used as the double harmonic element used in the YAG double harmonic laser. 3. The thickness of the battery terminal to be laser welded is 0.3 mm.
A method according to claim 1, characterized in that: 4. The method according to claim 1 or 3, wherein the lead terminal has a thickness of 0.3 mm or less. 5. The method according to claim 1, 3 or 4, wherein the laser welding is pulsed laser welding.