JPH09199088A - Sealed battery and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Problem] When a sealed battery is provided with a through hole that serves as a gas release hole when the internal battery is ruptured due to an increase in internal pressure, and the through hole is closed by laser welding the thin metal plate, the size thereof is different from that of the thin metal plate. By stacking a metal plate having the same or a small through hole on the metal thin plate and laser welding, the metal thin plate can stably block the through hole of the battery. [Effect] The safety mechanism according to the present invention can manufacture a sealed battery which is highly reliable and cost effective.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an explosion-proof sealed battery, which can be applied regardless of the type of battery, primary battery or secondary battery. In particular, the present invention is effective for a positive electrode and a negative electrode that use a material capable of inserting and extracting lithium as an active material, and a non-aqueous electrolyte secondary battery having a high energy density that uses a lithium ion conductive non-aqueous electrolyte.

[0002]

2. Description of the Related Art Non-aqueous electrolyte batteries using lithium metal or a substance capable of occluding and releasing lithium as an active material and a non-aqueous electrolyte as an electrolytic solution are excellent in high capacity, high voltage and high energy density. It is used in various mobile devices.

However, since the energy density is higher than that of other batteries, sufficient safety measures for explosion protection are required. Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 5-76740, a safety valve is ruptured at an internal pressure of a battery of 20 to 30 kg / cm ² to provide an explosion-proof function. The rupture pressure of ^{20 to} 30 kg / cm ² is considered to be an appropriate value considering the impact of rupture. However, this value is a value considered from the impact of breakage, and is not a value set in consideration of the shape change of the battery case due to the pressure increase inside the battery.

As the size of portable devices is reduced, the batteries used are also required to be reduced in size. Along with this, in order to effectively utilize the space occupied by the battery in the device, the battery is required to have a rectangular shape instead of a cylindrical shape. It is considered that the conventional rupture pressure was examined by using a tubular battery which is less likely to be deformed due to pressure, even considering the examples of Japanese Patent Application Publication No. 5-76740. Considering the shape change of the battery case due to the pressure increase inside the battery, the breaking pressure is preferably 20 kg / cm ² or less. In addition, mechanical strength against impact such as dropping is also required. Heretofore, it has been difficult to manufacture a safety mechanism which has both of these characteristics of safety and mechanical strength and is excellent in cost.

[0005]

As the size of portable devices is reduced, the batteries used are also required to be downsized. Along with this, in order to effectively utilize the space occupied by the battery in the device, the battery is required to have a rectangular shape instead of a cylindrical shape. The prismatic battery is installed so that there is as little extra space as possible against the equipment that uses it. Therefore, the deformation due to the internal pressure of the battery case will damage the device.

Since the cylindrical battery mainly receives the pressure inside the battery by the inner wall of the cylinder, the deformation of the battery case is small. On the other hand, since the prismatic battery receives pressure mainly on the four planes serving as the battery side surfaces, each plane, particularly a plane having a large area, is easily deformed. That is, it is necessary to determine the rupture pressure of the safety valve in consideration of this deformation.

FIG. 2 shows a stainless steel plate having a thickness of 0.3 mm (SU
Swelling of the battery case (size width 30 x thickness 6 x height 50 mm) produced in S304) against internal pressure (30 x
One side of the surface of 50 mm) is shown. In the experiment, the battery shown in FIG. 1 which does not have the through hole 3 and whose electrolyte solution injection hole 8a is not closed by the electrolyte solution injection hole lid 8 was used. Nitrogen gas was introduced through the electrolyte injection hole 8a and held at a predetermined pressure for 1 minute,
The pressure was released and the swelling of the battery case was measured with a micrometer. The measurement was repeated three times for each pressure. The maximum pressure that does not damage the equipment is a bulge of 2 mm on each side. 0.3 mm thick stainless steel (SUS30
In case of 4), the breaking pressure is 20 kg / c from the graph of FIG.
It should be below m ² (preferably around 15 kg / cm ² ). Similar experiments were conducted with iron (SPC-E) and aluminum (3003) cases. As a result, in order to have strength equivalent to stainless steel, 0.4 mm for iron
It has been found that a plate thickness of 0.5 to 0.6 mm is required for aluminum.

In order to achieve a breaking pressure of 20 kg / cm ² or less, it is necessary to provide a thin portion on the battery lid or the battery container. In many cases, the thin part is provided on the battery lid that is the easiest to install. In that case, in the case of a battery having a size of width 30 × thickness 6 × height 50 mm, the area of the thin portion can be only about 10 to 25 mm ² . Experimental result, 15kg / c
In order to break at around m ² , claims 4 and 5 are claimed.
The relationship between the thickness of the thin portion (metal thin plate) and the area of the thin portion (area of the through hole) as shown in 6 and 6 was necessary. That is, the thickness of the thin portion must be 10 μm or less for stainless steel and 15 μm or less for nickel.

It is technically very difficult to weld a thin metal plate of 10 to 15 μm to a battery container because only the thin metal plate may be melted and holes may be opened during welding. In addition, such a metal thin plate requires very careful handling. Since the product cut into a predetermined area is easily deformed and easily scratched or punctured, it is difficult to automatically supply the parts with a parts feeder or the like.

In order to facilitate welding and automatic supply, it is possible to use a metal thin plate thick (50 μm or more) and locally provided with a thin portion by etching or pressing, but the film thickness can be controlled. It was difficult and the manufacturing cost was high.

[0011]

[Problems to be Solved by the Invention] When a through hole A which is a gas vent hole for preventing rupture due to an increase in internal pressure of a sealed battery is provided and the through hole A is closed by laser welding a thin metal plate,
The through hole A of the battery can be reliably and easily closed by laminating a metal plate having a through hole B, which is not larger than the closed metal thin plate and having a through hole B, on the metal thin plate and performing laser welding.

FIG. 3 shows an example in which a metal plate 12a, which is slightly smaller than the metal thin plate 11a, is stacked on the metal thin plate 11a and seam welded to the battery lid 7. Figure 3 shows the laser welding points
As shown in FIG. 3, the welding spot 13 (between the outer periphery of the metal plate 12 and the through hole) or the welding spot 14 (outer peripheral portion of the metal plate 12) may be welded. 1 when welding the welding point 13
50 μm metal plate 12a, 10 μm thin metal plate 11a,
Since the battery lid 7 is simultaneously welded from above, a large amount of heat is generated, which may cause deformation of the battery container. On the other hand, when welding the welding spot 14, the metal plate 12a of 150 μm,
Since the end portion (outer peripheral portion) of the 10 μm thin metal plate 11a is welded, welding can be performed with relatively low energy. However, 1
It is necessary to accurately align the 50 μm metal plate 12a and the 10 μm metal thin plate 11a.

Even if the alignment is performed accurately, the position may be displaced due to the impact during laser welding or the thermal expansion of the material. In that case, the main welding may be performed after temporarily fixing several points by resistance welding or laser spot welding. If such welding is performed, the reliability of welding will be significantly improved. However, 1
It is very difficult to supply and position the 0 μm thin metal plate 11a. Therefore, it was devised that the thin metal plate 11b of 10 μm is formed into a tape and supplied by a reel.

When welding the welded portion 13, the tape may be cut after welding. For example, when welding to the battery lid 7, the portion indicated by the dotted line in FIG. 4 may be cut. Welding point 1
In the case of welding No. 4, as shown in FIG. 5, since the metal thin plate 11b that is off from the metal plate 12a is sufficiently thin and melts during welding, welding to the battery lid 7 and cutting can be performed at the same time.

In this case, since the tape-shaped thin metal plate 11b is sufficiently larger than the metal plate 12a, there is no need to worry about the positional deviation at the time of laser welding. Therefore, only the metal plate 12a is fixed by a holding jig provided with a deviation preventing mechanism. Laser welding may be performed in this state. If a holding jig is not used, resistance welding or laser spot welding may be used to temporarily fix several points, and then laser seam welding may be performed.

Welding thin metal sheets by the method shown in the present invention,
If a safety mechanism that blocks the through holes and breaks due to the internal pressure of the battery is used, the fluctuation of the breaking pressure is significantly reduced as compared with the case where a metal plate locally provided with a thin portion by etching or pressing is used. When a thin portion is locally provided by etching, pressing, etc., it is necessary to check the film thickness of each thin portion after forming the thin portion, but if the method using the metal thin plate of the present invention is used, Since it is only necessary to check the original thickness, the inspection cost can be greatly reduced.

[0017]

In general, in lap welding in which a thin material is overlaid on a thick material and welded by laser, the lower limit of the plate thickness of the thinner material is about 30 μm in the case of stainless steel. Considering the stability of welding, 50 μm or more is required.

In lap welding, the thinner the plate thickness, the more difficult the welding becomes. If there is a gap between the materials, there is no escape area for heat when welding with thin materials, the materials melt almost instantly and holes are opened. Further, even if there is no gap between the materials in the initial stage, since the thin material has low strength, it may be deformed by the impact at the time of welding or the surface tension of the melted metal, and a gap may be formed, resulting in failure of welding.

Therefore, in the present invention, a plate-shaped material is further stacked on a thin material. Thereby, the deformation of the thin material can be suppressed and the heat can be radiated. Further, if the portion of the welded portion 14 in FIG. 3 is seam welded with a laser, the portion where nothing is on the thin material is cut without a heat escape area during welding. By utilizing this phenomenon, as shown in FIG. 4, welding and cutting of thin material can be performed simultaneously.

[0020]

【Example】

[Example 1] A secondary battery manufactured by applying the safety mechanism of the present invention will be described below. LiCo as a positive electrode active material
85 parts by weight of a composite oxide of lithium, cobalt, and boron represented by O ₂ and 8 parts by weight of graphite as a conductive agent were pulverized and mixed in a mortar, and 7 parts by weight of polyvinylidene fluoride (PVDF) as a binder was added. N-methyl-2pyrrolidone (NMP) was mixed and dispersed in a solution dissolved in 51.3 parts by weight to prepare a positive electrode mixture slurry. Thickness 2 as a current collector
An aluminum foil of 0 μm was used. Next, the positive electrode slurry prepared above is applied and dried on both sides of a current collector provided with a conductive layer so that the mixture thickness on one side after drying and rolling is 60 μm,
It rolled using the roll press and produced the positive electrode sheet.
The positive electrode sheet produced in this way is 27.5 mm x 39 m
It was cut into a size of m to obtain a positive electrode plate.

A negative electrode was prepared in the same manner. 45 parts by weight of commercially available silicon monoxide (SiO) as a negative electrode active material and 40 parts by weight of graphite as a conductive agent were crushed and mixed in a mortar, and 15 parts by weight of a crosslinkable acrylic resin as a binder was added to 300 parts by weight of water. Was mixed and dispersed in a solution dissolved in a part to prepare a negative electrode mixture slurry. A copper foil having a thickness of 10 μm was used as a current collector. The negative electrode slurry prepared above was applied to both sides of a current collector provided with a conductive layer, and the mixture thickness on one side after drying and rolling was 27 μm.
It was applied so as to have a thickness of m, dried, and then rolled using a roll press. The negative electrode sheet prepared in this manner was used for 27.5
It was cut into a size of 39 mm to obtain a negative electrode plate.

The electrode body 2 was obtained by alternately stacking 17 positive electrode plates and 18 negative electrode plates with a separator made of polyethylene, which is a lithium ion permeable porous film, interposed therebetween (the outermost side is a mixture on one side). Negative electrode applied only to),
It was inserted into the outer can 1 which is a battery container made of stainless steel. The material of the outer can 1 is made of stainless steel having a thickness of 0.3 mm and also serves as a negative electrode terminal.

The metal lead plate 4 on the negative electrode side of the electrode body 2 is
It was welded to a stainless steel battery lid 7 having a thickness of mm. Further, the metal lead plate 5 on the positive electrode side of the electrode body 2 was welded to the positive electrode terminal 6 provided in the center of the battery lid 7. Next, the battery lid 7 and the outer can 1 were seam welded with a laser.

The electrolytic solution was injected through the electrolytic solution injection hole 8a provided in the battery lid 7, and then the electrolytic solution injection hole lid 8 made of stainless steel having a diameter of 150 μm was sealed by laser seam welding. The completed prismatic sealed battery is shown in FIG. The size was set to a width of 30 mm, a thickness of 6 mm, and a height of 50 mm.

The through hole 3 having an area of 11.15 mm ² opened in the battery cover 7 is formed as shown in FIG.
The metal thin plate 11a, which is a nickel foil of 0 μm, and the area 11.
A 150 μm stainless steel metal plate 12a having a 15 mm ² through hole was seam-welded with a laser to close it from the inside of the battery. As the welding spot, the position of the welding spot 14 in FIG. 3 was welded.

With respect to the three prismatic sealed batteries thus completed, holes were made in the electrolyte solution injection hole lid 8 and nitrogen gas was filled from there, and the pressure inside the battery was increased and the pressure at which the metal thin plate 11a was broken was examined. . The pressurizing rate was about 0.5 kg / sec. The breaking pressure was 15.2 kg / cm ² on average, and the difference between the maximum value and the minimum value was 2.3 kg / cm ² . The bulge of the battery at that time was 1.3 mm on one side.

[Embodiment 2] The internal structure of the battery is the same as that of Embodiment 1, and the metal thin plate 11c constituting the safety valve is arranged outside the battery to produce a prismatic sealed battery. The completed prismatic sealed battery is shown in FIG.

The through hole 3 having an area of 11.15 mm ² opened in the battery lid 7 is a thin metal plate 11 made of nickel foil of 15 μm.
c and a metal plate 12b made of stainless steel and having a through hole having an area of 22.5 mm ² and made of 150 μm were closed by seam welding with a laser. The welding spot was welded at the position of the welding spot 14 in FIG. By making the metal thin plate 11c on the outside of the battery and enlarging the through hole of the metal plate 12b, the area of the metal thin plate 11c receiving the pressure was increased.

With respect to the three prismatic sealed batteries thus completed, holes were made in the electrolyte solution injection hole lid 8 and nitrogen gas was filled from there, and the pressure inside the battery was increased and the pressure at which the metal thin plate 11c was broken was examined. . Breaking pressure is an average of 17.4 kg /
difference between the maximum value and the minimum value was 0.7 kg / cm ² in cm ^2. The bulge of the battery at that time was 1.4 mm on one side. Since the thickness of the thin metal plate 11c was improved and the quality was stabilized, the variation in the breaking pressure was reduced.

[Embodiment 3] With the same structure as in Embodiment 1, a rectangular sealed battery was prepared in the same manner as in the outer can 1 except that the material of the outer can 1 was changed to a nickel-plated steel plate (SPCE material) having a thickness of 0.4 mm. A hole was formed in the electrolyte solution injection hole lid 8 for the three completed prismatic sealed batteries, nitrogen gas was injected from there, and the pressure inside the battery was increased to examine the pressure at which the metal thin plate 11a was broken. The breaking pressure was 15.5 kg / cm ² on average, and the difference between the maximum value and the minimum value was 2.5 kg / cm 2. The bulge of the battery at that time was 1.4 mm on one side.

[Embodiment 4] A prismatic sealed battery was manufactured in the same manner as in Embodiment 2 except that the material of the outer can 1 was changed to a 0.4 mm thick nickel-plated steel plate (SPCE material). A hole was made in the electrolyte injection hole lid 8 for the three prismatic sealed batteries thus completed, and nitrogen gas was filled from there, and the pressure inside the battery was increased and the pressure at which the metal thin plate 11c was broken was examined. The breaking pressure was 18.1 kg / cm ² on average, and the difference between the maximum and minimum values was 2.8 kg / cm 2. The bulge of the battery at that time was 1.7 mm on one side.

[Embodiment 5] A prismatic sealed battery having the same structure as that of Embodiment 2 except that the metal thin plate 11c is made of stainless steel is manufactured. Through hole 3 with an area of 11.15 mm ² opened in the battery lid 7.
Is a thin metal plate 11c made of stainless steel (SUS304) having a size of 10 μm and a through hole 1 having an area of 22.5 mm ^2.
50 μm stainless steel (SUS304) metal plate 12
The b was closed by seam welding with a laser. The welding spot was welded at the position of the welding spot 14 in FIG. By making the metal thin plate 11c on the outside of the battery and enlarging the through hole of the metal plate 12b, the area of the metal thin plate 11c receiving the pressure was increased.

With respect to the three prismatic sealed batteries thus completed, holes were made in the electrolyte solution injection hole lid 8 and nitrogen gas was filled from there, and the pressure inside the battery was increased and the pressure at which the metal thin plate 11c was broken was examined. . Breaking pressure averaged 18.8 kg /
difference between the maximum value and the minimum value was 1.2 kg / cm ² in cm ^2. The bulge of the battery at that time was 1.6 mm on one side.

[Embodiment 6] Embodiment 1 is performed until the electrode body 2 is manufactured.
In the same manner as described above, a prismatic sealed battery was manufactured by making the battery container, the battery lid and the like out of aluminum. The electrode body 2 is obtained by alternately stacking 18 positive electrode plates and 17 negative electrode plates with a separator, which is a lithium ion permeable porous film, interposed therebetween (the outermost positive electrode is a positive electrode coated with a mixture on only one side). Then, it was inserted in the outer can 1 which is a battery container made of aluminum. The material of the outer can 1 is 0.5 mm thick aluminum alloy (300
3) Made and doubles as a positive electrode terminal.

The metal lead 4 on the positive electrode side of the electrode body 2 is 1 m.
It was welded to a battery lid 7 made of aluminum (3003) having a thickness of m. The metal lead plate 5 on the negative electrode side of the electrode body 2 was welded to the negative electrode terminal provided at the center of the battery lid 7. Next, the battery lid 7 and the outer can 1 were seam welded with a laser.

The electrolytic solution was injected through the electrolytic solution injection hole 8a provided in the battery lid 7, and then the aluminum electrolytic solution injection hole lid 8 having a thickness of 200 μm was seam-welded with a laser to seal it. The completed prismatic sealed battery is shown in FIG. The size was set to a width of 30 mm, a thickness of 6 mm, and a height of 50 mm.

The through hole 3 having an area of 11.15 mm ² opened in the battery lid 7 is a thin metal plate 11a which is an aluminum foil (pure aluminum) of 30 μm, and the through hole 3 having an area of 11.15 mm ² of 200 μm aluminum (pure aluminum). The metal plate 12a made of aluminum) was closed by seam welding with a laser. The welding spot was welded aiming at the position of the welding spot 13 in FIG.

With respect to the three prismatic sealed batteries thus completed, a hole was made in the electrolyte solution injection hole lid 8 and nitrogen gas was filled from there, and the pressure inside the battery was increased and the pressure at which the metal thin plate 11a was broken was examined. . Breaking pressure is 14.0 kg / average
difference between the maximum value and the minimum value was 1.8 kg / cm ² in cm ^2. The bulge of the battery at that time was 1.4 mm on one side.

[Comparative Example 1] The internal structure of the battery was the same as in Example 1, and a thin metal plate provided with a thin portion by etching was welded to the outside of the battery to produce a prismatic sealed battery.
The through hole 3 having an area of 11.15 mm ² opened on the battery cover 7 is
The thickness is 50 μm, the area is 35 mm ² , and the width is 300 μm in the center.
A thin metal plate made of stainless steel (SUS304TH) having a thin portion provided by etching a pattern with an X mark having a residual thickness of 15 μm was seam-welded with a laser to close the plate. With respect to the five prismatic closed batteries thus completed, holes were made in the electrolyte solution injection hole lid 8 and nitrogen gas was filled from there, and the pressure inside the battery was increased and the pressure at which the thin metal plate was broken was examined. The breaking pressure was 20.4 kg / cm ² on average, and the difference between the maximum value and the minimum value was 10.2 kg / cm ² . The bulge of the battery at that time was 2.2 mm on one side on average. The bulges vary from 1.5 to 3 mm, and large bulges can damage the equipment.

[Embodiment 7] The prevention of misalignment between a thin metal plate and a metal plate provided with a through hole during seam welding with a laser will be described with reference to FIGS. The thin metal plate 11b was taped on the battery lid 7 and supplied by a reel. Next, a metal plate 1 having a through hole is formed by a pressing jig 13 having a protrusion 15 and an air chuck 14 which serve as a mechanism for preventing a shift due to an impact due to seam welding.
Carry 2a to the position of Figures 7 and 8. Displacement prevention mechanism 15
Is a protrusion having substantially the same shape as the through hole of the metal plate 12a and having a height smaller than the thickness of the metal plate 12a, thereby preventing the metal plate 12a from being displaced. Air chuck 1
4 is for carrying the metal plate 12a to a predetermined position. With the metal plate 12a fixed as shown in FIG. 8, laser seam welding was performed along the outer periphery of the metal plate 12a in the directions of A, B, C, and D. Next, the pressing jig 13 was removed, and D → A welding was performed. Thereby, the metal plate 12
It was possible to perform reliable welding without a deviation.

This displacement prevention mechanism is effective when welding a metal plate of about 50 to 200 μm even if the structure is slightly different from that of the seventh embodiment. For example, even a safety mechanism (such as that shown in Japanese Patent Application Laid-Open No. 5-314959) in which the metal thin plate 11a and the metal plate 12a of FIG. 3 are thermocompression bonded in advance can be seam welded by a laser without deviation. .

In this embodiment, a silicon monoxide-based (Li _x SiO _z , 0 ≦ x, 0 ≦ y ≦ 1, 0 ≦ z silicon-containing oxide) material was used as the negative electrode active material. Needless to say, the same effect can be obtained when a negative electrode active material such as lithium metal or other compound is used.
In the future, it is expected that the capacity of prismatic sealed batteries will be further improved by improving the active materials. Examples of the negative electrode active material include mesophase pitch carbon, carbonaceous material based on coke-based carbon, transition metal oxide based, chalcogen compound based, and silicon-containing oxide based active materials described in this example. In particular, Li _x SiO _z and L shown in the examples of the present invention and L
high capacity of the i _x SiO _z, discharge capacity of the initial loss (initial and 2
Li _x Si _1-y Ti _y O _z and Li _x Si _1-y Sn _y O _z (0 ≦
x, 0 ≦ y ≦ 1, 0 ≦ z) and other silicon-containing oxides are expected to have high capacity. As the capacity of a battery increases, the energy density of the battery increases, and further safety, reliability, and economical efficiency in industry are required. Since the safety mechanism of the present invention operates reliably at a low pressure and has high reliability, it is particularly effective for a sealed battery having a high energy density. Moreover, the safety mechanism of the present invention is excellent in cost and has a high industrial value.

In this embodiment, width 30 × thickness 6 × height 50 m
Although only the m size battery is described, for other size batteries, the upper limit of the bulge should be decided based on the design value of the device used, and the bulge up to that point will activate the safety mechanism and the thickness of the outer can. The breaking pressure (refer to the formulas for the thickness and area of the thin metal plate described in the claims) may be determined. Considering the impact of breakage and damage to equipment, the breaking pressure is 20 kg.
/ Cm ² or less, and the bulge is preferably 2 mm or less on one side.

Further, in this embodiment, the metal plates 12a and 12b are used.
The thickness was 150 or 200 μm, but it was confirmed from the experimental results that it can be used from 50 to 500 μm without any problem. The thickness of the metal plate is easy to handle, weldable,
The thickness may be selected in the range of 50 to 500 μm in consideration of ease of making.

In the examples, only the case of the prismatic closed battery is shown, but the present invention is not limited to the prismatic battery, and other shapes such as a cylindrical shape, an elliptical shape and a polygonal shape are sealed according to the gist of the invention described above. The same applies to batteries.

[0046]

As described above in detail, the safety mechanism according to the present invention is highly reliable, cost effective, and industrially valuable.

[Brief description of drawings]

FIG. 1 is a sectional view of a prismatic sealed battery having a safety mechanism of the present invention.

[FIG. 2] Stainless steel with a thickness of 0.3 mm (SUS30
The swelling with respect to the internal pressure of the battery case (size width 30 x thickness 6 x height 50 mm) produced in 4) was shown.

FIG. 3 is a laser welding spot of the present invention.

FIG. 4 is a method for supplying and cutting a thin metal plate of the present invention.

FIG. 5 is a method for supplying and cutting a thin metal plate of the present invention. (Welding and supply are performed simultaneously)

FIG. 6 is a sectional view of a prismatic sealed battery having a safety mechanism of the present invention. (Welding the thin metal plate to the outside of the battery)

FIG. 7 is a cross-sectional view for explaining a mechanism for preventing displacement between a thin metal plate and a metal plate provided with a through hole during seam welding with a laser.

FIG. 8 is a perspective view seen from above for explaining a mechanism for preventing the metal thin plate and the metal plate provided with a through hole from being displaced during seam welding with a laser.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 outer can 2 electrode body 3 through hole 4 metal lead plate 5 metal lead plate 6 positive electrode terminal 7 battery lid 8 electrolyte solution injection hole lid 8a electrolyte solution injection hole 9 glass insulating material 10 insulating material 11 metal thin plate 12 metal plate 13 retainer Jig 14 Air chuck 15 Protrusion serving as a deviation prevention mechanism 16 Laser beam

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hiroshi Senda 1-8 Nakase, Mihama-ku, Chiba, Chiba Seiko Electronics Co., Ltd. (72) Hideharu Onodera 1-8 Nakase, Mihama-ku, Chiba, Chiba Prefecture Inside Seiko Electronics Co., Ltd.

Claims (13)

[Claims] 1. At least one through hole A is provided in a battery lid or a battery container of a sealed battery in which the battery lid is sealed by a method such as welding or caulking.
In a sealed battery having a safety mechanism of closing the battery with a metal thin plate and breaking by the internal pressure of the battery, a metal plate having a size not larger than the metal thin plate and having at least one through hole B is superposed on the metal thin plate. A sealed battery characterized by being seam-welded to a battery lid or a battery container. 2. The thickness of the metal plate having the through hole B is not smaller than the thickness of the metal thin plate.
The sealed battery described. 3. The thin metal plate is stainless steel, nickel,
The sealed battery according to claim 1, which is a nickel alloy, aluminum, an aluminum alloy, copper or a copper alloy. 4. The thin metal plate is made of nickel or a nickel alloy, and the thickness T (μm) of the thin metal plate and the through hole A or the through hole B on the outside of the battery of the thin metal plate.
The sealed battery according to claim 3, wherein the relation of the area S (mm ² ) of T = aS + 5 (where 0.3 <a <0.7) is satisfied. 5. The thin metal plate is made of stainless steel, and the thickness T (μm) of the thin metal plate and the area S (m) of the through hole A or the through hole B outside the battery of the thin metal plate.
The sealed battery according to claim 3, wherein the relationship of m ² ) is T = aS + 5 (where 0.1 <a <0.4). 6. The thin metal plate is made of aluminum, an aluminum alloy, copper or a copper alloy, and the thickness T (μm) of the thin metal plate and the through hole A or the through hole B on the outside of the battery of the thin metal plate. The sealed battery according to claim 3, wherein the relationship of the area S (mm ² ) of T = aS + 5 (where 1.5 <a <3.0) is satisfied. 7. The sealed battery according to claim 1, wherein the battery container has a prismatic shape, a prismatic shape having a large curved surface at a corner portion, an elliptical shape, or a cylindrical shape. 8. The active material of the sealed battery, wherein the positive electrode includes at least a lithium-containing oxide, and the negative electrode includes a carbonaceous material, a transition metal oxide, a chalcogen compound, Li _x SiO _z , and Li.
_x Si _1-y Ti _y O _z , Li _x Si _1-y Sn _y O _z (0 ≦ x, 0
≤ y ≤ 1, 0 ≤ z), etc., containing at least one silicon-containing oxide.
The sealed battery according to any one of 4, 5, 6, and 7. 9. At least a step of supplying the thin metal plate in the form of a tape onto at least one through hole A of a battery lid or a battery container, and at least one through hole having a size not larger than the thin metal plate. 3. A method of manufacturing a sealed battery according to claim 1, further comprising the step of seam welding with a laser to a battery lid or a battery container together with a metal plate having a hole B. 10. In the laser seam welding, a step of fixing the metal plate provided with the at least one through hole B with a holding jig provided with a mechanism for preventing displacement due to impact due to seam welding, and The method for producing a sealed battery according to claim 9, further comprising the step of seam welding with a laser. 11. In the laser seam welding, resistance welding for preventing the metal plate provided with the at least one through hole B from being displaced due to a shock caused by laser welding,
The method for manufacturing a sealed battery according to claim 9, further comprising a step of fixing by a method such as spot welding using a laser, and a step of performing seam welding using a laser in a fixed state. 12. Laser welding of the thin metal plate to a battery lid or a battery container by laser welding along the outer periphery of the metal plate provided with the at least one through hole B during seam welding with the laser. 10. The method according to claim 9, further comprising the step of simultaneously cutting from the tape.
1. The method for manufacturing the sealed battery according to any one of 1. 13. The method of manufacturing the sealed battery, wherein the positive electrode active material is manufactured from an active material containing at least a lithium-containing oxide, and the negative electrode active material is a carbonaceous material, a transition metal oxide, a chalcogen compound, Li _x. SiO _z , Li _x Si _1-y Ti _y O _z , Li
_x Si _1-y Sn _y O _z (0 ≦ x, 0 ≦ y ≦ 1, 0 ≦ z) or the like, and a step of manufacturing the active material containing at least one silicon-containing oxide. Item 9, 1
The method for manufacturing a sealed battery according to any one of 0, 11, and 12.