JP3230863B2 - Manufacturing method of non-aqueous electrolyte battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte battery provided with an explosion-proof mechanism.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable increase in the performance and miniaturization of electronic devices such as video cameras and headphone stereos. The demand for higher density is also increasing. Therefore, the development of nonaqueous electrolyte batteries using a material capable of occluding and releasing lithium, such as lithium metal, lithium alloy or carbonaceous material, as a negative electrode material has been actively performed.

[0003] However, danger is increasing with the increase in the density. For example, the non-aqueous electrolyte battery is supplied with a longer current than usual during charging and becomes an overcharged state, or a large current flows due to erroneous use or a failure of a device using the battery at the time of discharging and a short circuit state occurs. In such a case, the electrolytic solution is decomposed to generate gas, and the internal pressure of the battery increases. Further, if the overcharge or the short circuit continues, the temperature of the battery rises rapidly due to the heat generated by the decomposition of the electrolytic solution, and the battery may burst.

Therefore, it is essential for the practical use of the battery to prevent the internal pressure rise and the rupture due to the heat generation. For this reason, a lithium secondary battery provided with an explosion-proof safety valve mechanism as shown in FIG. 5 is disclosed in Japanese Utility Model Publication No. 59-15398. That is, a spiral electrode body 43 produced by winding the positive electrode 40 and the negative electrode 41 via the separator 42 is housed in the outer can 44. The insulating plate 45 is interposed between the electrode body 43 and the outer can 44, and electrically insulates the electrode body 43 and the outer can 44 from each other. The non-aqueous electrolyte is contained in the outer can 44. The sealing body 46 is attached by caulking and fixing to the opening of the outer can 44 via an insulating material 47, and seals the outer can 44. The sealing body 46 is a plate-like terminal plate 4.
8 and a hat-shaped terminal plate 49, a flexible thin plate 50, which is a component of a safety valve mechanism to be described later, is interposed therebetween, and the plate-shaped terminal plate 48 is bent over the periphery of the hat-shaped terminal plate 49. The structure is integrated. Positive electrode lead 51
Has one end connected to the positive electrode 40 and the other end connected to the lower end of the plate-like terminal plate 48.

[0005] The safety valve mechanism 52 is provided with the plate-shaped terminal plate 4.
By cutting two sides of a triangle near the center of the hat-shaped terminal plate 49 and a circular hole 53 provided at the center of the hatch 8, and bending the triangular portion formed by the cut downward. A blade 54 facing the formed hole 53, a triangular hole 55 opened in the hat-shaped terminal plate 49 by forming the blade 54,
8 and 49 and the flexible thin plate 50 interposed therebetween. The flexible thin plate 50 is composed of a composite member of a metal layer and a synthetic resin layer.

In the secondary battery having such a configuration, gas generated in the outer can 44 due to overcharge, short circuit, etc.
The electrode body 43 moves along the surface of the separator 42 toward the opening of the outer can 44, or flows along the surface of the separator 42 to the bottom of the outer can 44.
Is moved toward the opening of the outer can 44 by passing through the core space 56 at the center of the terminal plate, thereby applying pressure to the flexible thin plate 50 through the hole 53 of the terminal plate 48. As a result, the flexible thin plate 50 expands due to the pressure, and is broken by coming into contact with the blade 54 projecting downward from the hat-shaped terminal plate 49. Accordingly, the gas filled in the outer can 44 is released through the broken portion of the thin plate 50 and the triangular hole 55 of the terminal plate 49, thereby preventing the secondary battery from being ruptured.

In the secondary battery, it is necessary to increase the area of the positive electrode 40 and the negative electrode 41 facing each other in order to increase the capacity and the energy. However, in order to increase the specific surface area of the positive electrode 40 and the negative electrode 41 in a battery having a limited size, it is necessary to reduce the thickness of these electrode plates. The shape retention of the electrode body 43 thus reduced is reduced. As a result, when gas is generated in the outer can 44 due to the above-described overcharge or the like, the gas pressure is changed to the positive electrode 4 of the electrode body 43.
0, the negative electrode 41 and the separator 42 are added in the overlapping direction, so that the core space 56 is crushed and the gas passage is closed. Therefore, the gas diffused near the bottom of the electrode body 43 is confined, and the internal pressure of the battery is locally increased, so that the electrode body 43 itself is pushed up toward the sealing body 46 and the outer can is ruptured. There was a point.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the conventional problems, and can prevent the deformation of the core space of the electrode body, and can prevent the internal pressure from rising due to overcharge or short circuit. It is intended to provide a highly safe non-aqueous electrolyte battery capable of preventing the rupture of a battery.

[0009]

According to the present invention, there is provided an electrode body housed in an outer can, spirally wound between a positive electrode and a negative electrode with a separator interposed therebetween, and a non-electrode housed in the outer can. A non-aqueous electrolyte battery provided with a water electrolyte and a safety valve mechanism, wherein a pipe having a slit is arranged in a core space of the electrode body. Book
The method for manufacturing a nonaqueous electrolyte battery according to the present invention includes a positive electrode, a negative electrode,
Between the separator, the circumferential angle of 20 ~ 90 °
Using a pipe with a slit with a width within the range as the core
Winding and forming a spiral electrode body; and
And a non-aqueous electrolysis in the outer can.
A step of injecting a liquid, the outer can having a safety valve mechanism
And sealing with a sealing body.
Is what you do. FIG. 1 shows a non-aqueous electrolyte battery according to the present invention.
This will be described with reference to FIG.

The spiral electrode body 1 is housed in an outer can 2. The pipe 4 having the slit 3 is arranged in the core space of the electrode body 1. The electrode body 1 is produced by, for example, folding the separator 5 in half as shown in FIG. 2 and spirally winding the laminate with the negative electrode 6 therebetween and the positive electrode 7 with the pipe 4 as the core. You. The insulating plate 8 is interposed between the electrode body 1 and the outer can 2 and electrically insulates the electrode body 1 and the outer can 2 from each other. The non-aqueous electrolyte is contained in the outer can 2. The sealing body 9 is attached by caulking and fixing to the opening of the outer can 2 via an insulating material 10 to seal the outer can 2.
The sealing body 9 includes a plate-shaped terminal plate 11 and a hat-shaped terminal plate 12.
A flexible thin plate 13 which is a component of a safety valve mechanism to be described later is interposed therebetween, and the plate-shaped terminal plate 11 is bent over the upper edge of the hat-shaped terminal plate 12 to be integrated. ing. The positive electrode lead 14 has one end connected to the positive electrode 7 and the other end connected to the lower end of the plate-shaped terminal plate 11.

The safety valve mechanism 15 is provided with the plate-shaped terminal plate 1.
By cutting two sides of a triangle near the center of the hat-shaped terminal plate 12 and the circular hole 16 provided at the center of the first, and bending the triangular portion formed by the cut downward. A blade 17 facing the formed hole 16, a triangular hole 18 opened in the hat-shaped terminal plate 12 by forming the blade 17,
1 and 12 and the flexible thin plate 13 interposed therebetween. The flexible thin plate 13 is composed of a composite member of a metal layer and a synthetic resin layer.

The pipe 4 has a compressive strength of a pipe having an outer diameter of 4 mm and an inner diameter of 3 mm in order to prevent deformation due to the pressure of gas generated in the outer can 2 due to overcharge, short circuit, or the like. 30 kg / cm ² It is desirable to be formed from the above materials. Further, it is desirable that the pipe 4 is formed of a material that is not deformed by the heat generated when the internal pressure rises and does not react with the electrolyte or the like. Examples of such a material include metals such as stainless steel, iron, and nickel, and heat-resistant plastics such as polyimide.

It is desirable that the slit 3 provided in the pipe 4 made of the material having the compressive strength has a width in a range of a peripheral angle of 20 ° to 90 °. When the circumferential angle is less than 20 °, it is difficult to guide the gas generated at the center of the electrode body 1 into the pipe 4 through the slit 3. On the other hand, if the circumferential angle exceeds 90 °, a part of the electrode body 1 may sink into the slit 3 and the space of the pipe 4 may be narrowed.

The thickness of the pipe 4 made of the material having the compressive strength is desirably in the range of 0.1 mm to 0.6 mm. When the wall thickness is less than 0.1 mm, the strength of the pipe 4 is reduced, so that when the pressure of the gas is applied to the electrode body 1, the pipe 4 may be crushed and the electrode body 1 may be deformed. is there. On the other hand, when the thickness is 0.6
If it exceeds mm, the capacity of the battery may be reduced.

The positive electrode 7 has a configuration in which a chalcogen compound such as a lithium manganese composite oxide or a lithium cobalt composite oxide, an organic binder and a conductive material are mixed and formed into a sheet and pressed to a current collector. I have. As the organic binder, for example, polytetrafluoroethylene or the like can be used. As the conductive material, for example, acetylene black, graphite, or the like can be used.

In order to increase the specific surface area of the positive electrode 7 in a battery having a limited size to increase the capacity and energy of the battery, the current collector may have a thickness of, for example, 10 μm or less. It is desirable to use a thin metal plate of 35 μm. As the metal plate, for example, an aluminum foil, a stainless steel foil, a nickel foil or the like can be used. The negative electrode 6 has a configuration in which a mixture of a carbonaceous substance that absorbs and releases lithium ions and an organic binder is applied to a current collector and covered. As the organic binder, for example, an ethylene propylene copolymer or the like can be used.

The current collector has a thickness of, for example, 10 μm to increase the specific surface area of the negative electrode 6 in a battery having a limited size to increase the capacity and energy of the battery. It is desirable to use a thin metal plate of 35 μm. As the metal plate, for example, copper foil, stainless steel foil,
Nickel foil or the like can be used. The negative electrode 6 includes:
What consists of a metallic lithium sheet is also used. As the separator 5, for example, a polypropylene porous film, a polyethylene microporous film, or the like can be used.

The non-aqueous electrolyte is, for example, lithium hexafluorophosphate (LiPF ₆ ), lithium borofluoride (LiBF
₄ ) An electrolyte such as lithium perchlorate (LiClO ₄ ) is dissolved in a mixed solvent of propylene carbonate and dimethoxyethane or a mixed solvent of propylene carbonate and γ-butyl lactone.

[0019]

According to the present invention, a pipe having a slit is provided.
Is disposed in the core space of the spirally wound electrode body 1 wound with the separator 5 interposed between the positive electrode 7 and the negative electrode 6, so that the inside of the outer can 2 can be When the gas pressure is applied to the overlapping direction of the positive electrode 7, the negative electrode 6 of the electrode body 1, the negative electrode 6 and the separator 5 and to the pipe 4, the pipe 4 has a high compressive strength. The electrode body 1 can maintain its spiral shape without being crushed. Therefore, the gas can pass through the pipe 4 without being confined in the electrode body 1 or the bottom of the outer can 2. Further, the gas generated in the vicinity of the center of the electrode body 1 does not pass through the bottom of the outer can 2 and the slit 3
, The pressure applied to the pipe 4 can be reduced.
Therefore, the gas generated in the outer can 1 can be promptly moved to the safety valve mechanism 15 through the space of the pipe 4, thereby preventing rupture due to a local increase in battery internal pressure. can do.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. Example 1

L which is a composite oxide of lithium and cobalt
A paste was prepared by adding a conductive material and a binder to iCoO ₂ . The paste was applied to an aluminum substrate having a thickness of 20 μm and then dried to prepare a sheet-shaped positive electrode plate. Subsequently, a paste was prepared by adding a binder to a carbonaceous material supporting lithium or an alkali metal mainly composed of lithium. The paste is 10 μm thick
And then dried to produce a sheet-shaped negative electrode plate.

Next, as shown in FIG. 2 described above, a polyethylene microporous film as a separator is interposed between the positive electrode and the negative electrode, and a spirally wound electrode body is wound around a pipe having a slit as a core. Was prepared.
The pipe has an outer diameter of 4 mm, an inner diameter of 3 mm,
The one having a slit having a peripheral angle of 23 ° was used.

Next, the electrode body is housed in a stainless steel outer can having an outer diameter of 17 mm and a height of 50 mm, and after injecting the electrolyte, it is caulked and sealed using a sealing body.
The cylindrical non-aqueous electrolyte battery shown in FIG. 1 having a capacity of 700 mAh was assembled. The electrolyte used was one in which a solute of 1 mol of lithium phosphofluoride (LiPF ₆ ) was dissolved in a mixed solvent of propylene carbonate and dimethoxyethane. Example 2

A non-aqueous electrolyte battery similar to that of Example 1 was assembled using a spiral electrode body similar to that of Example 1 except that a pipe having a slit having a circumferential angle of 38 ° was used as the core. . Example 3

A nonaqueous electrolyte battery similar to that of Example 1 was assembled using a spiral electrode body similar to that of Example 1 except that a pipe having a slit having a peripheral angle of 57 ° was used as the core. . Example 4

A nonaqueous electrolyte battery similar to that of Example 1 was assembled using a spiral electrode body similar to that of Example 1 except that a pipe having a slit having a circumferential angle of 76 ° was used as the core. . Example 5

A nonaqueous electrolyte battery similar to that of Example 1 was assembled using a spiral electrode body similar to that of Example 1 except that a pipe having a slit having a circumferential angle of 8 ° was used as the core. . Example 6

A nonaqueous electrolyte battery similar to that of Example 1 was assembled using a spiral electrode body similar to that of Example 1 except that a pipe having a slit having a circumferential angle of 96 ° was used as the core. . Comparative Example 1 A nonaqueous electrolyte battery similar to that of Example 1 was assembled using a spiral electrode body similar to that of Example 1 except that no pipe was disposed in the core space.

Examples 1 to 6 and Comparative Example 1
20 batteries each, and a current of 2 A is set to 24
After flowing for an hour, an overcharge test was performed to check the number of ruptured batteries. The results are shown in Table 1 below. Table 1 Sample Number of ruptured batteries Example 1 0 Example 2 0 Example 3 0 Example 4 0 Example 5 0 Example 6 0 Comparative example 1 15

As is clear from Table 1, in the batteries (Examples 1 to 6) provided with an electrode body in which a pipe having a slit was disposed in the core space, no battery was ruptured, and the battery was ruptured. It can be seen that it is possible to prevent. This is because the pipe was not collapsed, the shape of the electrode body was maintained, and gas generated due to overcharging was able to quickly pass through the slit and the pipe and escape from the safety valve mechanism. On the other hand, a battery provided with an electrode body in which no pipe was disposed in the core space (Comparative Example 1)
Then, the number of ruptured batteries was as large as 15 pieces. The swelling of the bottom of the outer can was measured for each of the 20 batteries after the tests of Examples 1 to 6 and Comparative Example 1. The results are shown in Table 2 below. Table 2 Sample Circumferential Angle of Slit (°) Swelling of Bottom of Outer Can (mm) Example 1 23 0.49 Example 2 38 0.42 Example 3 57 0.43 Example 4 76 0.44 Example 5 8 0.72 Example 6 96 0.82 Comparative Example 1 No pipe 0.95

As is clear from Table 2, the batteries of Examples 1 to 4 have smaller swelling at the bottom of the outer can and lower internal pressure than the batteries of Examples 5, 6 and Comparative Example 1. Understand.

Further, in the battery of Example 5, the gas generated near the center of the electrode body could not be sufficiently introduced into the pipe due to the small slit width, and the internal pressure increased. On the other hand, in the battery of Example 6, since the slit width was large, a part of the electrode body was embedded in the slit, the space of the pipe became narrow, and the internal pressure increased. Actually, when the battery of Example 6 was disassembled, it was confirmed that a part of the electrode body was cut into the slit and the space of the pipe was narrowed.

On the other hand, in the battery of Comparative Example 1, since the shape of the electrode body was low, the core space of the electrode body was crushed, the internal pressure was significantly increased, and bursting occurred. Actually, when the battery of Comparative Example 1 was disassembled, it was confirmed that the core space of the electrode body was crushed.

In the first to sixth embodiments, the non-aqueous electrolyte battery having the safety valve mechanism shown in FIG. 1 has been described.
The present invention is not limited to this. For example, the present invention can be similarly applied to a non-aqueous electrolyte battery having a safety valve mechanism shown in FIGS. 3 and 4 described below.

The outer casing 21 also serving as the negative electrode terminal houses the electrode body in which the above-mentioned pipe having the slit is disposed in the core space. Sealing body 2 having a hole in the center
2 is hermetically attached to the outer can 21. The positive electrode pin terminal 23 is attached to the center hole of the sealing body 22 by a hermetic seal via a glass insulating material 24 so that both ends thereof protrude from the upper and lower surfaces of the sealing body 22. And the sealing body 22 is insulated.

The safety valve mechanism 25 has a valve membrane formed at the bottom thereof by a hole 26 opened in the sealing body 22 and a groove 27 provided at a location corresponding to the hole 26 at the outer surface of the sealing body 22. And the thin film 28 formed. The hole 26 includes, for example, three arc-shaped holes formed concentrically with the center of the sealing body 22. The groove 2
Numeral 7 comprises, for example, a circular groove 29 provided at a position corresponding to the hole 26 and a linear groove 30 intersecting with the circular groove 29 and extending radially from the center of the sealing body. The thin film 28 has, for example, a ring shape.

In the non-aqueous electrolyte battery having such a structure, the gas generated in the outer can 21 due to overcharge, short circuit, etc. passes through the pipe and passes through the safety valve mechanism 25.
Side to apply pressure to the valve membrane portion of the thin film 28 through the arc-shaped hole 26 formed in the sealing body 22 to break the valve membrane. Therefore, the gas escapes from the hole 26 and the rupture portion of the valve membrane to the outside, and the rupture of the battery can be prevented as in the first to sixth embodiments.

In the first to sixth embodiments, as a method of arranging the pipe in the core space, the pipe is wound as a core between the positive electrode and the negative electrode with the separator interposed therebetween. Although the method has been described, it is also possible to adopt a method of preparing the electrode body in advance and inserting the pipe into the core space of the electrode body. Examples 1 to 6
Although the description has been made with reference to the cylindrical nonaqueous electrolyte battery, the present invention can be similarly applied to a prismatic nonaqueous electrolyte battery. In the first to sixth embodiments, the description has been made by applying the present invention to a secondary battery. However, the present invention can be similarly applied to a primary battery.

[0039]

As described above in detail, according to the present invention, it is possible to prevent the deformation of the core space of the electrode body, and it is possible to prevent the rupture when the internal pressure rises due to overcharge, short circuit, or the like. It is possible to provide a highly safe non-aqueous electrolyte battery.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a nonaqueous electrolyte battery according to the present invention.

FIG. 2 is a perspective view showing a state in which winding of an electrode body of the battery of FIG. 1 is started.

FIG. 3 is a perspective view showing another non-aqueous electrolyte battery of the present invention.

FIG. 4 is an exploded perspective view showing a main part of the battery of FIG. 3;

FIG. 5 is a sectional view showing a conventional nonaqueous electrolyte battery.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electrode body, 2 ... Outer can, 3 ... Slit, 4 ... Pipe,
5 separator, 6 negative electrode, 7 positive electrode, 15 safety valve mechanism.

Continued on the front page (72) Inventor Hiroyoshi Nose 3-4-10 Minamishinagawa, Shinagawa-ku, Tokyo Inside Toshiba Battery Co., Ltd. (72) Eijiro Matsuzaka 1-3-1 Yoko, Kawasaki-ku, Kawasaki-shi, Kanagawa Asahi Kasei Katsuhiko Inoue, Inventor Katsuhiko Inoue 1-3-1, Yoko, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Asahi Kasei Kogyo Co., Ltd. (56) References JP-A-4-332481 (JP, A) 129267 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 2/12 105 H01M 10/40

Claims (1)

(57) [Claims] A separator is interposed between a positive electrode and a negative electrode.
And a slit of which width is within the range of 20-90 °
A pipe having a core is wound as a core, and a spiral electrode body is formed.
A step of manufacturing, a step of housing the electrode body in an outer can, a step of injecting a non-aqueous electrolyte into the outer can , and sealing the outer can using a sealing body having a safety valve mechanism.
A non-aqueous electrolyte battery characterized by comprising the steps of:
Production method.