JPH09245765A - Battery with lead terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the soldering of a lead terminal for an electric circuit board and the welding of a lead terminal for an element battery by differing the thickness of a positive terminal side lead terminal from the thickness of a negative terminal side lead terminal in a battery. SOLUTION: In a battery with a read terminal, the thickness of a positive pole side lead terminal 10 differs from that of a negative terminal side lead terminal 9. If there is a difference between the allowable welding outputs of the positive and negative pole terminal sides, it is preferable that the thickness of the lead terminal on the terminal side of the unit cell with its low allowable welding output is thin and the thickness of the lead terminal on the terminal side of the unit cell with its high allowable welding output is thick. It is preferable that the lead terminal on one pole terminal side of the unit cell is of stainless steel 005 to 0.15mm in thickness and that the lead terminal on the other pole terminal side of the unit cell is of stainless steel of 0.15 to 0.4mm in thickness. Since the lead terminal on one pole terminal side is thin and is superior in flexibility, soldering to the electronic circuit board is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery with lead terminals, in which lead terminals are welded to positive and negative bipolar terminals, and more particularly to the thickness of the lead terminals.

[0002]

2. Description of the Related Art A battery with lead terminals, in which lead terminals are welded to both positive and negative electrodes, has been widely used by soldering the lead terminals to an electronic circuit board due to the development of electronic equipment. Above all, flat type lithium batteries are widely used for memory backup and the like.

A lead terminal of a conventional battery with a lead terminal, in which a lead terminal is welded to both positive and negative electrode terminals, has the same thickness on the positive electrode side and the negative electrode side. That is, the thickness of the lead terminal is 0.2 mm or 0.1 mm on both the positive and negative electrode terminals.

The battery with the lead terminal having this structure has the following problems (A) and (B), which the manufacturer and the user have troubled. (A) For example, when the thickness of the lead terminal is 0.2 mm (relatively thick) on both the positive and negative electrode terminals side, the strength of the lead terminal is high, so when the lead terminal is soldered and attached to the electronic circuit board. The battery with a lead terminal has high stability (the lead terminal is less likely to be deformed due to vibration, shock, etc.), but the lead terminal is not strong enough to be flexible, so the electronic circuit board of the lead terminal is poor. The workability of soldering to is poor. Because, when the lead terminals of the positive and negative bipolar terminals do not match the soldering position on the electronic circuit board due to variations in the welding position of the lead terminals, variations in the dimensions of the lead terminals, variations in the external dimensions of the battery, etc.
It is common to correct the lead terminal by deforming it,
Because it is difficult. Incidentally, it is very often that the lead terminals of the positive and negative bipolar terminals do not match the soldering positions on the electronic circuit board.

Further, in welding the unit cell terminal and the lead terminal, there is a weldable range in the welding output, and the weldable range is the minimum welding output capable of reliably welding the unit cell terminal and the lead terminal. The range is up to the allowable welding output (maximum welding output that does not seriously adversely affect the constituent members of the cell or the lead terminals). When the lead terminal becomes thicker, the minimum welding output for surely welding the terminal of the unit cell and the lead terminal becomes higher and the weldable range becomes narrower. That is,
When the lead terminal has a thickness of 0.2 mm, it is more difficult to control the welding output than when the lead terminal has a thickness of 0.1 mm. For this reason, when welding a thick lead terminal to a terminal of a unit cell which originally has a low allowable welding output, the welding work efficiency and the welding yield are deteriorated at present. (B) For example, when the thickness of the lead terminal is 0.1 mm (relatively thin) on both of the positive and negative electrode terminals, the lead terminal is low in strength and excellent in flexibility. Good workability for soldering to the board. This is because, when the lead terminals of the positive and negative bipolar terminals do not match the soldering positions on the electronic circuit board, the lead terminals can be easily deformed and corrected. In addition, welding with a lead terminal thickness of 0.1 mm makes it easier to control welding output than welding with a lead terminal thickness of 0.2 mm. For this reason, when welding a thin lead terminal to a terminal of a unit cell which originally has a low allowable welding output, the welding work efficiency and the welding yield are good. However, since the lead terminal is low in strength because it is thin, the stability of the lead terminal-equipped battery when the lead terminal is soldered and attached to the electronic circuit board is low.

Incidentally, a battery with a lead terminal has been devised in which the portion of the lead terminal to be welded to the unit cell is made sufficiently thinner than the thickness of other portions (Japanese Utility Model Laid-Open No. 61-16863). Certainly, according to the method of this invention, the weldability of the lead terminal to the unit cell is improved, and the stability of the lead terminal battery when the lead terminal is soldered and attached to the electronic circuit board is high. However, merely thinning the portion of the lead terminal to be welded to the unit cell cannot improve the workability of soldering to the electronic circuit board because the thick lead terminal leads to poor flexibility. Moreover, stainless steel is generally used as the material of the lead terminal, and it is very difficult to partially process the stainless steel, which is not practical.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, and the workability of soldering a lead terminal to an electronic circuit board and the weldability of a lead terminal to a unit cell are sufficiently good,
Provided is a lead terminal-equipped battery in which the stability of the lead terminal-equipped battery when the lead terminals are soldered and attached to an electronic circuit board is sufficiently high.

[0008]

SUMMARY OF THE INVENTION The present invention is a battery with a lead terminal in which a lead terminal is welded to a positive electrode terminal and a negative electrode terminal of a unit cell, the thickness of the positive electrode terminal side lead terminal and the negative electrode terminal side lead terminal. It is characterized by different thickness.

If there is a difference between the allowable welding output on the positive electrode terminal side and the allowable welding output on the negative electrode terminal side, the lead terminal on the terminal side of the unit cell having a low allowable welding output is thin,
It is preferable that the lead terminal on the terminal side of the unit cell having a high allowable welding output is thick.

The lead terminal on the one pole terminal side of the unit cell is made of stainless steel having a thickness of 0.05 to 0.15 mm, and the lead terminal on the other pole terminal side of the unit cell has a thickness of 0. It is preferably stainless steel in the range of 0.15-0.4 mm.

[0011]

[Function] The thickness of the lead terminal on the positive electrode terminal side is different from the thickness of the lead terminal on the negative electrode terminal side. That is, the lead terminal on the one pole terminal side of the unit cell is thinned, and the lead terminal on the other pole terminal side of the unit cell is thickened. As a result, since the lead terminal on the one-pole terminal side is thin, the strength of the lead terminal is low and the flexibility is excellent, so that the workability of soldering to the electronic circuit board is improved. This is because when the lead terminals of the positive and negative bipolar terminals do not match the soldering positions on the electronic circuit board, the lead terminals on the one pole side can be easily deformed and corrected. The stability of the battery with lead terminals when the lead terminals are soldered and attached to the electronic circuit board may be inferior to that when the lead terminals are thick on both the positive and negative pole terminal sides. It is superior to the case where the thickness of both positive and negative electrode terminals is thin. By the way, the size of the unit cell,
If the thickness of the lead terminals of the positive and negative pole terminals is individually selected in consideration of the weight and the allowable welding output, the workability of soldering the lead terminals on the electronic circuit board and the lead terminals on the electronic circuit board are improved. It is possible to obtain sufficient stability of the battery with lead terminals when the battery is soldered and attached.

When there is a difference between the allowable welding output on the positive electrode terminal side and the allowable welding output on the negative electrode terminal side, the lead terminal on the terminal side of the unit cell having a low allowable welding output is thin and the allowable welding output is high. By thickening the lead terminal on the terminal side of the battery, welding work efficiency and welding yield are improved as compared with the case of welding a thick lead terminal on the terminal side of the unit cell having a low allowable welding output. This is because the weldable range of the welding output becomes wider and the welding output management becomes easier. By the way,
The case where there is a difference between the allowable welding output on the positive electrode terminal side and the allowable welding output on the negative electrode terminal side is the case of batteries as shown in the following (a) to (c). (A) A flat battery comprising a negative electrode containing lithium as an active material and a positive electrode containing manganese dioxide as an active material. In the case of this battery, the melting point of manganese dioxide is 1000 ° C. or higher, whereas the melting point of lithium is 186 ° C. Therefore, the terminal side of the negative electrode side using lithium as the active material is the positive electrode using manganese dioxide as the active material. This is because the allowable welding output is much lower than the side terminal. Further, since lithium has a high thermal conductivity on the negative electrode terminal side, it is necessary to consider melting of the separator that separates the negative electrode from the positive electrode. It is generally said that the higher the welding output, the larger the amount of heat generated during welding and the higher the temperature of the peripheral portion. (B) A battery in which a metal lid is welded to an opening of a metal outer can that also serves as a terminal on one side, and a metal terminal on the other side is attached to a through hole of the metal lid via an insulating resin. This is because in the case of this battery, when welding the lead terminal to the metal terminal on the other electrode side, the welding output must be lowered in consideration of the melting of the insulating resin. Incidentally, if the insulating resin is extremely melted, the battery contents may pop out and an electrical short circuit may occur between the positive and negative electrodes. (C) A sealing body is provided at the opening of the metal outer can that also serves as a terminal on one side, and the sealing body is provided with an exhaust hole, and the other side is welded or caulked to the sealing plate. And a plate-shaped metal terminal cap that also functions as a terminal of the battery, and a rubber valve body in a compressed state that closes the exhaust hole is provided in the sealing body. In the case of this battery, when welding the lead terminal to the dish-shaped metal terminal cap that also serves as the terminal on the other electrode side, the welding output must be lowered in consideration of softening and melting of the rubber valve body. This is because. Incidentally, when the rubber valve body is softened, the valve operating pressure changes, and when the rubber valve body is extremely melted, the exhaust hole cannot be completely closed (the valve is opened).

The thickness of the lead terminal is determined by considering the strength of the lead terminal itself, the welding output when spot welding to the terminal of the unit cell by laser welding or electric resistance welding, and the conductivity of the lead terminal itself. Generally, stainless steel having a thickness of 0.05 to 0.4 mm is widely used. Further, the flexibility of the lead terminal, which affects the workability of the lead terminal to be soldered to the electronic circuit board, and the stability of the battery with the lead terminal when the lead terminal is soldered and attached, are made of stainless steel. As a result of examination, it was found that the branch point viewed from the thickness of 0.15 mm was 0.15 mm. Therefore, the lead terminal on the one pole terminal side of the unit cell is stainless steel with a thickness in the range of 0.05 to 0.15 mm, and the lead terminal on the other pole terminal side of the unit cell is 0.15 to 0.15 mm in thickness. Stainless steel in the 0.4 mm range is preferred.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below embody the technical idea of the present invention and do not limit the present invention.

FIG. 1 is a perspective view when the present invention is applied to a flat lithium battery, FIG. 2 is a plan view of FIG. 1, FIG. 3 is a front view of FIG. 1, and FIG. 4 is a flat lithium battery of FIG. It is a schematic sectional view.

First, a flat lithium battery which is a unit cell to which the present invention is applied will be described. This battery comprises a negative electrode 1 using lithium as an active material, a positive electrode 2 using manganese dioxide as an active material, a separator 3 for separating the negative electrode and the positive electrode, a negative electrode can 4 made of stainless steel (SUS304) having a thickness of 0.2 mm, From a 0.2 mm thick positive electrode can 5 made of stainless steel (SUS430), a negative electrode current collector 6 made of stainless steel (SUS316), a positive electrode current collector 7 made of stainless steel (SUS316), a gasket 8 made of polypropylene, etc. Become. Therefore, the negative electrode 1 and the positive electrode 2 face each other with the separator 3 impregnated with the nonaqueous electrolytic solution interposed therebetween, and are housed in the battery case formed by the negative electrode can 4 and the positive electrode can 5, and the negative electrode 1 is the negative electrode current collector. The positive electrode 2 is connected to the negative electrode can 4 via 6, and the positive electrode 2 is connected to the positive electrode can 5 via the positive electrode current collector 7. Then, the chemical energy generated inside the battery can be taken out from the negative electrode can 4 and the positive electrode can 5 as electric energy to the outside. That is, the negative electrode can 4 is the negative electrode terminal of this battery, and the positive electrode can 5 is the positive electrode terminal of this battery.
The outer dimensions of this battery are 12 mm in diameter and 2 mm in thickness.

Next, the application of the present invention to this flat lithium battery will be described. Since the thickness of the positive and negative bipolar terminals of this battery is 0.2 mm, the thickness of the lead terminals welded to the positive and negative bipolar terminals is preferably 0.2 mm or less. This is because the thickness of the lead terminal to be welded to the terminal of the unit cell is less than the thickness of the terminal of the unit cell because the thermal adverse effect on the unit cell is less (Japanese Patent Laid-Open No. 61-179062). Then, the stainless steel (SUS3
04), the thickness of the lead terminal, the flexibility of the lead terminal that influences the soldering workability of the lead terminal to the electronic circuit board, and the lead terminal battery when the lead terminal is attached by soldering. 0.15 m, which is a branch point in terms of the thickness of the stainless steel lead terminal in stability
The thickness was 0.1 mm thinner and 0.2 mm thicker than m.
Also, comparing the allowable welding output of the positive and negative electrode terminals of this battery, the melting point of manganese dioxide is 1000 ° C. or higher, whereas the melting point of lithium is 186 ° C., which is much lower than that of manganese dioxide, and the thermal conductivity of lithium is high. Since it is high, it is also necessary to consider the melting of the separator. Therefore, the allowable welding output is lower on the negative electrode terminal side. Therefore, since it is preferable to make the negative electrode terminal side lead terminal 9 thinner, the thickness (X in FIG. 1) of the negative electrode terminal side lead terminal 9 to be welded to the negative electrode terminal is set to 0.1 mm and welded to the positive electrode terminal. The thickness of the lead terminal 10 on the positive electrode terminal side (Y in FIG. 1) was 0.2 mm. The lead terminal 9 on the negative electrode terminal side and the lead terminal 10 on the positive electrode terminal side, the thicknesses of which were selected in this way, were spot-welded to the flat lithium battery, which is a unit cell, by laser welding or electric resistance welding. Reference numeral 11 is a heat-shrinkable tube, which prevents the positive electrode can 5 and the negative terminal lead terminal 9 from coming into contact with each other and electrically short-circuiting.

Finally, the negative electrode terminal of this flat lithium battery has a thickness of 0.1 mm, 0.15 mm and 0.2 m.
m lead wire made of stainless steel (SUS304)
Weldable range of welding output at each thickness when spot welding with a laser (minimum welding output that can reliably weld the unit cell terminal and the lead terminal to the unit cell or the lead terminal Table 1 shows the welding input voltage as a scale for the range up to the maximum welding output). It should be noted that the welding input voltage and the welding output are in a proportional relationship, and the welding input voltage can be sufficient as a measure of the weldable range of the welding output.

[0019]

[Table 1]

From Table 1, the lead terminal thickness is 0.2 mm.
It is understood that the width of the weldable range (difference between the minimum value and the maximum value) increases as the thickness decreases from 0 to 0.1 mm. And this is because the lead terminal thickness is 0.2mm to 0.1m.
As the thickness decreases to m, the welding input management (that is, the welding output management) when spot welding the lead terminal to the negative electrode terminal of this flat type lithium battery with a laser becomes easier, and the welding work efficiency and welding It means that the yield will be improved. That is, according to the conventional method of welding the lead terminals of the same thickness to the positive and negative electrode terminals of the unit cell, the lead terminal having the same 0.2 mm thickness as the positive terminal lead terminal 10 is welded to the negative terminal. That is, mass productivity of batteries with lead terminals is improved. According to the conventional method of welding lead terminals having the same thickness to the positive and negative electrode terminals of the unit cell, a battery with lead terminals having a lead terminal thickness of 0.1 mm on both the positive and negative electrode terminals was used. Batteries with lead terminals (the thickness of the negative terminal lead terminal 9 is 0.1 mm, and the thickness of the positive terminal lead terminal 10 is 0.2 mm).
It is needless to say that the lead terminal-equipped battery is more stable when the lead terminals are soldered and attached to the electronic circuit board.

[0021]

EFFECT OF THE INVENTION Since the lead terminal on the one pole terminal side of the unit cell is thin and the lead terminal on the other pole terminal side of the unit cell is thick, the lead terminal on the one pole terminal side is thin. Since its strength is low and its flexibility is excellent, the workability of soldering the lead terminal to the electronic circuit board is improved. Also, in order to improve the workability of soldering the lead terminal to the electronic circuit board and the weldability of the lead terminal to the unit cell, the lead terminal battery with a thin lead terminal on both the positive and negative electrode terminals side can be used on the electronic circuit board. The stability of the battery with lead terminal is high when the lead terminal is attached by soldering.

When there is a difference between the allowable welding output on the positive electrode terminal side and the allowable welding output on the negative electrode terminal side, the lead terminal on the terminal side of the unit cell having a low allowable welding output is thin and the element having a high allowable welding output is used. By thickening the lead terminal on the terminal side of the battery, welding work efficiency and welding yield are improved as compared with the case of welding a thick lead terminal on the terminal side of the unit cell having a low allowable welding output.

Therefore, by implementing the present invention, the workability of soldering the lead terminal to the electronic circuit board and the weldability of the lead terminal to the unit cell are sufficiently good, and the lead terminal is soldered to the electronic circuit board. It is possible to provide a battery with a lead terminal having a sufficiently high stability of the battery with a lead terminal when attached by being attached.

[Brief description of drawings]

FIG. 1 is a perspective view when the present invention is applied to a flat lithium battery.

FIG. 2 is a plan view of FIG.

FIG. 3 is a front view of FIG. 1;

FIG. 4 is a schematic cross-sectional view of the flat type lithium battery of FIG.

[Explanation of symbols]

 1 ・ ・ Negative electrode 2 ・ ・ Positive electrode 4 ・ ・ Negative electrode can 5 ・ ・ Positive electrode can 9 ・ ・ Negative electrode terminal side lead terminal 10 ・ ・ Positive electrode terminal side lead terminal

Claims (4)

[Claims] 1. A battery with a lead terminal, in which a lead terminal is welded to a positive electrode terminal and a negative electrode terminal of a unit cell, wherein the thickness of the positive electrode terminal side lead terminal is different from the thickness of the negative electrode terminal side lead terminal. Batteries with lead terminals. 2. There is a difference between the allowable welding output on the positive electrode terminal side and the allowable welding output on the negative electrode terminal side, and the allowable welding output is low. The lead terminal on the terminal side of the unit cell is thin and the allowable welding output is high. The lead terminal battery according to claim 1, wherein the lead terminal on the terminal side of the battery is thick. 3. The lead terminal on one electrode terminal side of the unit cell,
The thickness of the lead terminal on the other electrode terminal side of the unit cell is 0.
The battery with lead terminal according to claim 1, wherein the battery is stainless steel in a range of 15 to 0.4 mm. 4. The unit cell is a flat battery including a negative electrode using lithium as an active material and a positive electrode using manganese dioxide as an active material, wherein the lead terminal on the negative electrode terminal side is thinner. The battery with lead terminals according to claim 3.