JPH1064512A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery, having a small upper part space of an electrode group with high capacity energy density, which can shorten a collector lead. SOLUTION: An electrode group 5 is received in a metal-made battery vessel 1, in an opening part thereof, the battery vessel is connected to a metal-made battery cover 2 in a connection part 7. In the battery cover 2, a metal-made hollow bushing 4 is calked to be mounted through an electric insulating packing 3. Passing through in this hollow part, a collector lead 6 of the electrode group 5 is air-tightly connected in a connection part in an upper surface of the bushing 4 to form a positive or negative electrode battery terminal of a battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery in which a metal battery cover and a battery case are joined at an opening of the battery case, and more particularly to an improvement in a battery terminal.

[0002]

2. Description of the Related Art In a conventional battery in which a metal battery cover and a battery container are joined at an opening of the battery container, an electrode group including a positive electrode, a negative electrode, and a separator is housed in the battery container, and then the battery cover is mounted on the battery cover. A battery terminal, which is provided in advance and is electrically insulated from the battery lid, is joined to the current collecting lead of the electrode group. After that, the electrolyte is injected into the battery container, and then the battery cover is fitted in the opening of the battery container, and the peripheral edges of the battery cover and the battery container are joined by laser welding or the like to form a hermetic seal. This structure
In particular, it is frequently used for prismatic batteries. The reason is that it is difficult to adopt a method of caulking the battery lid and the battery container via an electrically insulating packing as in the case of a conventional cylindrical battery. Prismatic batteries have the advantage of being small in volume and being able to effectively use small spaces when mounted on small portable devices. Recently, various types of mobile batteries such as mobile phones have been developed. It is attracting attention as a power source.

[0003]

However, in these batteries, the battery lid is fitted into the opening of the battery container after the current collecting lead of the electrode group and the battery terminal provided on the battery lid are joined. If the current collecting lead is not long, the working interval for the joining and fitting cannot be secured. Therefore, the length of the current collecting lead becomes longer, so that the voltage drop at the time of high-rate discharge is large, and a space for accommodating a long current collecting lead becomes necessary.
There is a problem that the volume energy density cannot be improved. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide a battery which can shorten a current collecting lead, has a small space above an electrode group, and has a high volume energy density.

[0004]

In order to achieve the above object, the present invention provides a battery in which a metal battery cover and a battery container are joined at an opening of the battery container, wherein the battery cover has Is mounted with a metal bushing having a hollow structure through an electrically insulating packing, and the battery container houses an electrode group with a current collecting lead, and the current collecting lead of the electrode group has the hollow structure. The metal bushing is inserted from the lower surface thereof and joined to the upper surface of the bushing, and the upper surface of the bushing forms a battery terminal.

The metal battery lid, battery container, and bushing used in the present invention are not particularly limited as long as they have corrosion resistance in the range of operating voltage with the electrolyte used in the battery. Can be used, but steel, nickel-plated steel, stainless steel, nickel, aluminum, copper and the like are preferable. The electrically insulating packing is not particularly limited, such as a synthetic resin, and a conventionally known one can be used. For joining the current collecting lead and the bushing, a suitable method such as gas welding, arc welding, plasma welding, laser welding, electron beam welding, or resistance welding is used as appropriate according to the material to be used, but is not particularly limited.

[0006]

FIG. 1 shows an example of an embodiment of a battery according to the present invention. FIG. 1 is a cross-sectional view of a battery. A metal battery container 1 houses an electrode group 5 and is joined to a metal battery lid 2 at a joint portion at an opening thereof. A metal hollow bushing 4 is caulked and attached to the battery lid 2 via an electrically insulating packing 3. The joints are hermetically joined at the joints to form a positive or negative battery terminal of the battery. In the method of assembling the battery, first, the electrode group 5 is inserted into the battery container 1, and after the electrolyte is injected, the battery cover 2 in which the packing 3 and the bushing 4 are previously installed is fitted to the battery container 1. At that time, the current collecting lead 6 penetrates through the hollow portion of the bushing 4. Thereafter, the battery container and the battery lid are joined to form a joint 7
Is formed, and the bushing 4 and the current collecting lead 6 are joined to form a joint 8, thereby completing the battery. With such a configuration, the current collecting lead can be shortened, and the space between the electrode group and the lid can be reduced.

[0007]

The present invention will be described in more detail with reference to examples. Example 1 (Production method of positive electrode) A positive electrode was produced as follows. A positive electrode mixture was prepared by mixing 88 parts by weight of lithium cobaltate (LiCoO ₂ ) powder, 8 parts by weight of graphite as a conductive material, and 4 parts by weight of polyvinylidene fluoride as a binder.
-Dispersed in methylpyrrolidone to prepare a positive electrode mixture slurry. This positive electrode material mixture slurry is used as a positive electrode current collector with a thickness of 20%.
It was uniformly coated on both sides of a strip-shaped aluminum foil of μm, dried, and then compression-molded.

(Preparation method of negative electrode) The negative electrode was prepared as follows. Mesocarbon microbeads (particle diameter: 1 to 50 μm, carbon content: 99.000) as spherical highly crystalline graphite particles
90% by weight of 9%, true density of 2.1 g / cm3, d002 = 3.366 angstroms) and 10 parts by weight of polyvinylidene fluoride as a binder were mixed to prepare a negative electrode mixture, which was dispersed in N-methylpyrrolidone. Thus, a negative electrode mixture slurry was prepared. This negative electrode mixture slurry was uniformly applied to both sides of a 20 μm-thick strip-shaped copper foil serving as a negative electrode current collector, dried, and then compression-molded.

(Method of Manufacturing Battery) Positive electrode (200 μm thick)
m) of 27 mm × 47 mm dimensions and 11 negative electrodes (200 μm thickness) of 27 mm × 47 mm dimensions were laminated via a polyethylene microporous film separator (25 μm thickness) to form an electrode group. The current collecting lead was formed by providing an uncoated portion on the current collector and cutting out this portion. 2 and 3 show the structure of the electrode. The negative electrode includes a mixture application section 9 and a current collecting lead 10. The positive electrode includes a mixture application section 11 and a current collecting lead 12. The electrode group is a rectangular stainless steel battery container (30 mm × 50 mm × 5.5 m).
m) The negative electrode current collecting lead was bundled into 5 pieces, and the five negative electrode current collecting leads were bundled, and the remaining six pieces were bundled together and joined to the other battery container side wall by ultrasonic welding. The ten positive electrode current collecting leads were bundled and ultrasonically welded to the aluminum pole 13 shown in FIG. As a non-aqueous electrolyte, 1 mol / mol of a mixed solvent of ethylene carbonate and dimethyl carbonate (1: 1 volume ratio)
After dissolving 1 l of lithium hexafluorophosphate dissolved therein, a stainless steel battery cover 2 to which an aluminum hollow bushing 4 has been previously caulked via a polypropylene packing 3 is fitted to the battery container 1. Then, the pole 13 was passed through the hollow portion of the bushing 4. The fitting portion between the battery lid 2 and the battery container 1 was joined by YAG laser welding. Further, the bushing 4 and the pole 13 were joined and sealed on the upper surface of the bushing 4 by YAG laser welding to form a positive battery terminal.

The battery fabricated in this way is 500 m
A, 4.1V, after charging for 2 hours, 2.8 at 100mA
The capacity obtained by discharging at room temperature to V was 600 mAh. The volumetric energy density was 260 Wh / l. After charging under the same conditions, the battery was discharged to 2.8 V at 1.5 A at room temperature, and the capacity obtained was 535 mAh.

Comparative Example A positive electrode and a negative electrode were produced in the same manner as in Example 1. Positive electrode (thickness 2
An electrode group was formed in the same manner as in Example 1 except that a 27 μm × 40 mm (00 μm) dimension and a 27 mm × 40 mm negative electrode (200 μm thickness) were used. The electrode group is a rectangular stainless steel battery container 1 (30 mm × 5
0 mm × 5.5 mm), and five negative electrode current collecting leads were bundled, one battery container side wall was bundled, and the other six were bundled and joined to the other battery container side wall by ultrasonic welding. The current collecting leads of the positive electrode were bundled in ten pieces and ultrasonically welded to the aluminum positive electrode terminal 14 previously attached to the stainless steel battery lid 2 via the polypropylene packing shown in FIG. At this time, the length of the current collecting lead of the positive electrode was four times longer than that of Example 1 due to welding work. As a non-aqueous electrolyte, a mixed solvent of ethylene carbonate and dimethyl carbonate (1:
After dissolving 1 mol / l of lithium hexafluorophosphate in 1 volume ratio), the battery lid 2 was fitted to the battery container 1, and the fitted portion was joined by YAG laser welding and sealed. . In order to house the current collecting lead of the positive electrode inside the battery case 1, about three times as much space as in Example 1 was required.

The battery manufactured in this way is 500 m
A, 4.1V, after charging for 2 hours, 2.8 at 100mA
The capacity obtained by discharging at room temperature to V was 510 mAh. The volumetric energy density was 220 Wh / l. After charging under the same conditions, the capacity obtained by discharging the battery at 1.5 A to 2.8 V at room temperature was 340 mAh.

Although the embodiments have been described with reference to a prismatic battery in which electrodes are stacked, the present invention can be applied to a battery in which electrodes are wound and accommodated in a rectangular or cylindrical battery container. Further, although the non-aqueous electrolyte secondary battery has been exemplified, the present invention can be applied to other battery systems.

[0014]

As described above, according to the present invention, the distance between the current collecting lead and the battery terminal can be shortened, and the space above the electrode group can be reduced. A battery having excellent rate discharge characteristics can be obtained. In addition, when the battery cover is fitted to the battery container, it is possible to save labor such as folding to accommodate the current collecting lead above the electrode group.

[Brief description of the drawings]

FIG. 1 is a sectional view of a battery showing an example of the present invention.

FIG. 2 is a plan view showing a negative electrode according to an example of the present invention.

FIG. 3 is a plan view showing a positive electrode according to an example of the present invention.

FIG. 4 is a perspective view showing a bonding state between a pole and a current collecting lead in the embodiment of the present invention.

FIG. 5 is a cross-sectional view of a short side surface of a battery used in a comparative example.

[Explanation of symbols]

1 is a battery container, 2 is a battery cover, 3 is an electrically insulating packing,
4 is a hollow bushing, 5 is an electrode group, 6 is a current collecting lead, 7
Is a junction between the battery lid and the battery container, 8 is a junction between the bushing and the current collecting lead, 9 is a negative electrode mixture applying section, 10 is a negative electrode current collecting lead, 11 is a positive electrode mixture applying section, 12 Is a positive collector lead, 13 is a pole, 14 is a positive terminal

Claims (1)

[Claims] 1. A battery in which a metal battery cover and a battery case are joined at an opening of the battery case, and a hollow metal bushing is attached to the battery cover via an electrically insulating packing. The battery container accommodates an electrode group with a current collecting lead, and the current collecting lead of the electrode group is inserted from the lower surface of the hollow metal bushing and joined to the upper surface of the bushing. Wherein the upper surface of the bushing forms a battery terminal.