JPH08329972A - Battery - Google Patents

Abstract

PURPOSE: To provide a battery, in which the generation of breakdown of a film and the generation of pin hole of a metal foil are prevented even in the case where vibration and impact are applied to the battery, by eliminating a bending part of the film. CONSTITUTION: This invention is related to a battery. An electrode body is formed by laminating a negative electrode and a positive electrode. A lead part of each negative electrode and positive electrode is welded to each terminal. Each side plate l, 2 has a fixing means for fixing a terminal hole, into which the terminal is to be inserted through a seal material, and for fixing the terminal. Each edge of the starting part and the end part of a film 12 are welded, and the surfaces, with which the edges of both sides and the surfaces of each step part of the two side plates 1, 2 contact, are welded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery suitable for application to, for example, a power source for portable equipment or a secondary battery as a large-sized and large-capacity power source.

[0002]

2. Description of the Related Art In recent years, advances in electronic technology have led to advances in performance, miniaturization, and portability of electronic devices, and secondary batteries used in these electronic devices are also required to have high energy density. It is like this.

Conventionally, secondary batteries used in these electronic devices include nickel-cadmium batteries and lead batteries, but these batteries are low in discharge potential and high in energy density. It was also insufficient.

Therefore, recently, a material such as lithium, a lithium alloy, or a carbon material that can dove and dedove lithium ions is used as a negative electrode, and a lithium composite oxide such as a lithium cobalt composite oxide is used as a positive electrode. Research and development of lithium ion secondary batteries, which are water electrolyte secondary batteries, are being conducted. This battery has a high battery voltage, a high energy density, little self-discharge, and excellent cycle characteristics.

From the problems of energy saving, environmental pollution, etc., development of high voltage (tens to hundreds of volts), high energy capacity, and high energy density batteries used for electric power storage and electric vehicles is strongly desired. .

[0006]

However, in the above-mentioned conventional battery, the structure of the battery has a spiral electrode body formed by winding a flat plate-shaped electrode, or a flat electrode body formed by laminating electrodes. In most cases, the battery structure has a cylindrical or angular metal deep drawing case.

The battery of this structure has good case strength, heat dissipation, etc., but due to manufacturing restrictions of the case, it is difficult to form an extremely thin case and the battery weight is large.

Although a case molded of plastic is also used, in the case of a lithium-ion battery, the gas and moisture barrier properties of the case are particularly required, and it is necessary to make the case considerably thicker for ordinary plastics, and volume efficiency is improved. And the heat dissipation during charging and discharging was poor.

As the thinnest and lightest battery case, a bag-like battery structure by heat sealing using a film in which a polyolefin resin is laminated on the inner layer surface of a metal foil and a thermoplastic resin is laminated on the outer layer is proposed. However, in this bag-shaped battery, the laminated electrodes are usually used as the film 3
One side or a plurality of sides are folded by heat-sealing the sides or four sides to wrap them in a bag shape, and bending the sealing part of the bag in consideration of external influences such as damage to the bag due to impact or vibration. In most cases, the bag-shaped battery is stored in a metal or plastic hard case and used as the final battery.

Therefore, in the bag-shaped battery described above, since the seal portion of the bag and the periphery of the seal portion are bent, the film at the bent portion is damaged, or even if it is not damaged, a pinhole is formed in the ultrathin metal foil. However, there was a problem such as the occurrence of water vapor permeation.

The present invention has been made in view of the above problems and provides a battery which has no bent portion and which is free from damage to the film and pinholes in the metal foil even when vibration or shock is applied. The purpose is to provide.

[0012]

The battery of the present invention comprises an electrode body in which a negative electrode and a positive electrode are laminated or wound, two terminals in which the respective lead portions of the negative electrode and the positive electrode are welded, and a seal. A terminal hole for inserting the terminal through the material and a fixing means for fixing the terminal, one or both of which has two side plates, and the sides of the start portion and the end portion thereof are heat-welded, and 2 on both sides
And a film having heat-welded surfaces contacting the surfaces of the stepped portions of the two side plates.

Further, the battery of the present invention is the battery having the above-mentioned structure in which one or both side plates have a cleavage valve.

[0014]

According to the battery of the present invention, an electrode body in which a negative electrode and a positive electrode are laminated or wound, two terminals in which the respective lead portions of the negative electrode and the positive electrode are welded, and a sealing material are provided. One or both of the side plates having a terminal hole into which the terminal is inserted and a fixing means for fixing the terminal, and the sides of the start portion and the end portion thereof are heat-welded, and the sides on both sides thereof are heat-welded. Since there is a film in which the surfaces where the two and the surfaces of the stepped portions of the two side plates contact each other are heat-welded, the film has no bent portion.

[0015]

EXAMPLE An example of the battery of the present invention will be described below with reference to FIGS.
This will be described with reference to FIG. Here, a rectangular battery was examined. The manufacturing method will be described below. First, a negative electrode is produced. First, after calcination in an inert gas stream, crushed carbon having an average particle size of 20 μm
A slurry is prepared by dispersing 10 parts by weight of vinylidene fluoride resin as a binder in N-methylpyrrolidone. This is applied on both sides of a current collector of a copper foil having a thickness of 10 μm to produce an electrode original plate having a thickness of 180 μm, and this is used as a lead part, leaving an unapplied part, and the applied part is 109 mm ×
A negative electrode was obtained by cutting it to 270 mm.

Next, a positive electrode is prepared. First, 91 parts by weight of LiCo ₂ powder having an average particle size of 15 μm, 6 parts by weight of graphite as a conductive agent, and 3 parts by weight of vinylidene fluoride resin as a binder are dispersed in N-methylpyrrolidone to prepare a slurry. This is applied to both sides of an aluminum foil current collector having a thickness of 20 μm to prepare an electrode original plate having a thickness of 150 μm.
It was cut to have a size of 265 mm to obtain a positive electrode.

Next, as shown in FIG. 1, 47 electrodes of the negative electrode and 46 electrodes of the positive electrode were placed between the electrodes obtained above, and a microporous polyethylene film of 145 mm × 365 mm with a thickness of 50 μm was interposed therebetween. The laminated electrode body 10 was obtained by laminating the lead portions between the positive and negative electrodes on both sides (or each lead portion being on one side), and wrapping and fixing an adhesive tape around the outer periphery. The thickness of this laminated electrode body 10 was 21 mm. The theoretical capacity is about 50 Ah.

Next, as shown in FIG. 1, the lead portions 9 on both ends of the laminated electrode body 10 obtained above were bundled and welded to the terminals 3 and 4 by ultrasonic welding.

Next, as shown in FIG. 1, the terminals 3 and 4 to which the electrodes are welded are inserted into the terminal holes 6 and 7 of the side plates 1 and 2 made of polypropylene through the O-ring 5 made of Teflon,
It was fixed to the side plates 1 and 2 by screwing. As the side plate, a thermoplastic resin can be widely used, but a polyolefin resin is particularly suitable. Further, the side plates are provided with terminal holes 6 and 7, and it is sufficient to fix the terminals through the holes and through an O-ring or a gasket.

Next, as shown in FIG. 2, the laminated electrode body 1
0 for sheet-like film 12 (12 μ for polyester
m / Al is 7 μm / polypropylene is 60 μm) is a stepped portion 1a of the side plates 1 and 2 on both sides thereof.
Wrap to cover 2a.

Next, as shown in FIG. 3, the film 12 is provided with a step portion 1 of the side plates 1 and 2 on each side of the starting portion and the ending portion of the film 12 wound as described above.
In a state in which it is tightly wound on a and 2a, it is heat-welded to form a seal portion 12c. Further, the surfaces where both sides of the film 12 are in contact with the surfaces of the stepped portions 1a and 2a of the side plates 1 and 2 are heat-welded to form the seal portions 12a and 12b.

The method of winding the film 12 around the laminated electrode body 10 and the stepped portions 1a, 2a of the side plates 1, 2 is not limited to the above-mentioned method, but a tubular film in which one end of the film is heat-welded is used. Insert the laminated electrode body 10,
Open both end openings of this film to the stepped portion 1 of the side plates 1 and 2.
A method of obtaining a battery by heat welding to a and 2a may be used.

As the film used in the present invention, a film obtained by laminating a heat-fusible resin on one side or both sides of a foil such as aluminum in order to have a barrier property against gas and moisture is used. However, a polyolefin-based resin is suitable as the resin for the inner layer of the electrolysis tank in consideration of the fusion property with the side plate and the resistance to the electrolytic solution. In particular,
Resins such as polyethylene and polypropylene are most suitable for batteries using non-aqueous electrolytes such as lithium ion batteries, which are said to have the highest energy density among secondary batteries.

Next, as shown in FIG. 4, the electroporation obtained as described above is inserted into a hard case 13 made of polypropylene and having a rectangular hollow shape with a wall thickness of 1.5 mm.
The unwelded portion of the film 12 of 2 is welded by ultrasonic welding to form welded portions 13a and 13b. The hard case may be housed in a metal or other plastic hard case for the purpose of preventing the film from being damaged by the external force of the electrolysis structure.

Finally, after injecting an electrolyte solution in which LiPF ₆ was dissolved at a ratio of 1 mol / 1 into a mixed solvent of propylene carbonate and diethyl carbonate through the holes for the cleaving plate of the side plate, as shown in FIG. Cleavage plate 14 (12 μm for polyester / 7 μm for Al / 3 for polypropylene
A 0 μm laminated film was punched out to have a diameter of 19 mm and heat-welded to a hole for a cleaving plate to form a cleaving valve 15 to obtain a final battery.

Next, the characteristics of the battery produced in this example were examined. As a result, the completed battery is charged for the first time,
When discharged at a constant current of 0.2 C (10 A), a capacity of 50 Ah was obtained, and a battery having no problem was obtained. Also, 1/3
Even in the cycle test of C (17A), the capacity retention rate was 85% at 300 cycles, which was a problem-free result.

From the above, according to this embodiment, the bag-shaped battery has the highest weight energy density and volume energy density and excellent heat dissipation, and further, there is no bent portion in the film, and there is no vibration or impact. It is possible to obtain a battery in which damage to the film and pinholes in the metal foil do not occur even if added.

Further, in the present invention, gas is used as the electrolytic cell material,
Since a film that blocks moisture and the like is used, the resin thickness can be reduced when a resin hard case is used, so that the energy density can be higher than that of a conventional resin case.

In addition, when the battery is in an abnormal state such as an external short circuit or an internal short circuit, the internal pressure of the battery may rise rapidly, and a cleaving valve is required to prevent the battery case from rupturing. By opening a hole for cleaving in the side plate and installing a cleaving plate type cleaving valve by heat-sealing a film with thermoplastic resin laminated on one side or both sides of the metal foil on the seating surface of this hole, abnormal battery internal pressure It is safe because the internal pressure can be released when the temperature rises.

Next, another embodiment of the battery of the present invention will be described with reference to FIGS. Here, a cylindrical battery was examined. The manufacturing method will be described below.
First, a negative electrode is produced. First, 90 parts by weight of carbon having an average particle size of 20 μm obtained by pulverizing after firing in an inert gas stream, and vinylidene fluoride resin 1 as a binder.
A slurry is prepared by dispersing 0 part by weight of N-methylpyrrolidone. This is applied to both sides of a current collector of a copper foil having a thickness of 10 μm to prepare an electrode original plate having a thickness of 180 μm.
It was slit to have a size of 5 mm × 5400 mm, and a nickel lead foil having a thickness of 30 μm was welded to the uncoated portion to obtain a negative electrode.

Next, a positive electrode is prepared. First, 91 parts by weight of LiCo ₂ powder having an average particle size of 15 μm, 6 parts by weight of graphite as a conductive agent, and 3 parts by weight of vinylidene fluoride resin as a binder are dispersed in N-methylpyrrolidone to prepare a slurry. This is applied to both sides of an aluminum foil current collector having a thickness of 20 μm to prepare an electrode original plate having a thickness of 150 μm.
It slit so that it might become 5300 mm, and the lead foil made of aluminum with a thickness of 50 μm was welded to the uncoated portion to obtain a positive electrode.

Next, as shown in FIG. 5, each lead portion between the positive and negative electrodes is provided on both sides with a microporous polyethylene film having a thickness of 50 μm interposed between the negative electrode and the positive electrode obtained as described above. (Or each lead part is on one side), and an adhesive tape was wound around the outer periphery and fixed. Further, positive and negative lead foils were welded to the terminals 3 and 4 by spot welding to obtain a wound electrode body 14. The theoretical capacity was about 20 Ah.

Next, as shown in FIG. 5, the terminals 3 and 4 to which the electrodes are welded are connected to the disc-shaped side plates 1 and 2 made of polypropylene.
It was inserted into the terminal holes 6 and 7 through Teflon O-rings and fixed to the side plates 1 and 2 by screwing.

Next, as shown in FIG. 6, the wound electrode body 1
4 is a sheet-like film 12 (polyester is 12μ
m / Al is 7 μm / polypropylene is 60 μm) is a stepped portion 1a of the side plates 1 and 2 on both sides thereof.
Wrap to cover 2a.

Next, as shown in FIG. 7, the film 12 is attached to the stepped portion 1 of the side plates 1 and 2 on each side of the start portion and the end portion of the film 12 wound as described above.
In a state in which it is tightly wound on a and 2a, it is heat-welded to form a seal portion 12c. Further, the sides on both sides of the film 12 and the surfaces in contact with the surfaces of the stepped portions 1a and 2a of the side plates 1 and 2 are heat-welded to form seal portions 12a and 12b.

The method of winding the film 12 around the spirally wound electrode body 14 and the stepped portions 1a, 2a of the side plates 1, 2 is not limited to the above-described method, but a tubular film having one end of the film heat-welded Insert the wound electrode body 14 into
Open both end openings of this film to the stepped portion 1 of the side plates 1 and 2.
A method of obtaining a battery by heat welding to a and 2a may be used.

Next, as shown in FIG. 8, the electroporation obtained as described above is inserted into a hard case 13 made of polypropylene and formed into a hollow cylindrical shape, and the film 1 of the side plates 1 and 2 is inserted.
2 is welded to the unwelded part by ultrasonic welding,
The welded portions 13a and 13b were used.

Finally, after injecting an electrolyte solution in which LiPF ₆ was dissolved at a ratio of 1 mol / 1 into a mixed solvent of propylene carbonate and diethyl carbonate from the hole for the cleavage plate of the side plate, as shown in FIG. Cleavage plate 14 (12 μm for polyester / 7 μm for Al / 3 for polypropylene
A 0 μm laminated film was punched out to have a diameter of 19 mm and heat-welded to a hole for a cleaving plate to form a cleaving valve 15 to obtain a final battery.

Next, the characteristics of the battery produced in this example were examined. As a result, the completed battery is charged for the first time,
When a constant current discharge was performed at 0.2 C (4 A), a capacity of 20 Ah was obtained, and a battery having no problem was obtained. Also, 1 / 3C
Even in the cycle test of (7A), the capacity retention rate was 85% at 300 cycles, which was a problem-free result.

From the above, also in this embodiment, the same effects as those of the above-described embodiments can be obtained.

Next, another embodiment of the battery of the present invention will be described with reference to FIGS. Here, a rectangular battery was examined. Further, the steps up to the step of producing the battery case are the same as those in the first embodiment. That is, first, a negative electrode and a positive electrode are produced. Next, as shown in FIG. 9, the electrodes obtained above were 47 negative electrodes, 46 positive electrodes, and a microporous polyethylene film between them, and each lead part between the positive and negative electrodes was on both sides. (Or each lead part is on one side), and an adhesive tape was wound around the outer periphery and fixed to obtain a laminated electrode body 10.

Next, as shown in FIG. 9, the lead portions at both ends of the laminated electrode body 10 obtained above were bundled and welded to the terminals 3 and 4 by ultrasonic welding.

Then, as shown in FIG. 9, the terminals 3 and 4 to which the electrodes are welded are inserted into the terminal holes 6 and 7 of the side plates 1 and 2 made of polypropylene via the O-ring made of Teflon and screwed. It fixed to the side plates 1 and 2 by the stop and the laminated electrode body was obtained.

Next, as shown in FIG. 10, the laminated electrode body 10 is wrapped in such a manner that the sheet-shaped film 12 covers the stepped portions 1a, 2a of the side plates 1, 2 on both sides thereof.

Next, as shown in FIG. 11, the film 12 is provided with the stepped portion 1 of the side plates 1 and 2 on each side of the start portion and the end portion of the film 12 wound above.
In a state in which it is tightly wound on a and 2a, it is heat-welded to form a seal portion 12c. Further, the surfaces where both sides of the film 12 are in contact with the surfaces of the stepped portions 1a and 2a of the side plates 1 and 2 are heat-welded to form the seal portions 12a and 12b. Up to this point, the procedure is the same as in the first embodiment.

Next, the battery cell obtained as described above is shown in FIG.
A stainless steel plate having a plate thickness of 0.3 mm as shown in FIG. 3 is bent into a square shape and inserted into a hard case 17 whose ends are fixed by spot welding, and then, as shown in FIG. The sides were fixed with screws to form screw fixing portions 17a and 17b.

Finally, after injecting the electrolytic solution through the cleaving plate hole of the side plate, as shown in FIG. 13, the cleaving plate is heat-welded to the cleaving plate hole to form a cleaving valve 15 to obtain a final battery. .

Next, the characteristics of the battery produced in this example were examined. As a result, the completed battery is charged for the first time,
When discharged at a constant current of 0.2 C (10 A), a capacity of 50 Ah was obtained, and a battery having no problem was obtained. Also, 1/3
Even in the cycle test of C (17A), the capacity retention rate was 85% at 300 cycles, which was a problem-free result.

From the above, also in this embodiment, the same effects as those of the first embodiment can be obtained.

The thickness of the film used in the present invention,
The material, the sealing method between the terminal and the film, the sealing material, the shape of the electrode body, and the method of injecting the electrolytic solution are not limited to the present embodiment, and generally used Of course, it can be used.

Further, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0052]

As described above, according to the present invention,
Highest weight energy density and volume energy density,
It is possible to obtain a bag-shaped battery having good heat dissipation, which has no bent portion in the film and which is free from damage to the film and pinholes in the metal foil even when vibration or shock is applied.

Further, when the hard case made of resin is used, the resin thickness can be molded thin, so that the energy density can be made higher than that of the conventional resin case.

In addition, a cleaving hole is formed in the side plate, and a film in which a thermoplastic resin is laminated on one side or both sides of the metal foil is heat-sealed on the seat surface of the hole to provide a cleaving plate type cleaving valve. The internal pressure can be released when the battery internal pressure rises abnormally.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part such as a side plate used in an embodiment of a battery of the present invention.

FIG. 2 is a perspective view showing a laminated electrode body and a film wound around a side plate.

FIG. 3 is a perspective view showing a battery used in one embodiment of the battery of the present invention.

FIG. 4 is a perspective view showing an embodiment of the battery of the present invention.

FIG. 5 is a perspective view showing a main part such as a side plate used in another embodiment of the battery of the present invention.

FIG. 6 is a perspective view showing a wound electrode body and a film wound around a side plate.

FIG. 7 is a perspective view showing an electric cell used in another embodiment of the present invention.

FIG. 8 is a perspective view showing another embodiment of the battery of the present invention.

FIG. 9 is a perspective view showing a main part such as a side plate used in another embodiment of the battery of the present invention.

FIG. 10 is a perspective view showing a laminated electrode body and a film wound around a side plate.

FIG. 11 is a perspective view showing an electrode used in another embodiment of the battery of the present invention.

FIG. 12 is a perspective view showing a hard case used in another embodiment of the battery of the present invention.

FIG. 13 is a perspective view showing another embodiment of the battery of the present invention.

[Explanation of symbols]

 1, 2 Side plate 1a, 2a Stepped part 3, 4 Terminal 5 O-ring 6, 7 Terminal hole 8 Screw 9 Lead part 10 Laminated electrode body 11 Cleavage plate hole 12 Film 12a, 12b, 12c Seal part

Claims (2)

[Claims] 1. An electrode body in which a negative electrode and a positive electrode are laminated or wound, two terminals welded to respective lead portions of the negative electrode and the positive electrode, and the terminal is inserted via a sealing material. Either one or both of the terminal holes and the fixing means for fixing the terminals are heat-welded to each side of a start portion and an end portion of the two side plates, and both sides and the above-mentioned two sides. A battery comprising: a film having heat-welded surfaces in contact with surfaces of stepped portions of two side plates. 2. The battery according to claim 1, wherein one or both of the side plates has a cleavage valve.