JPH09245753A - Paired battery and grouped battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain paired batteries and grouped batteries with its superior insulation property by permitting a single battery, a single battery terminal part, and the outer face outer face of a connection lead to be entirely covered with a film of insulation material in the paired batteries to be used by connecting plural single batteries in series or parallel. SOLUTION: Coating of polyphenylene sulfide which is insulation coating is sprayed over the entire exterior of a cover plate 4, is applied, and is completely covered and insulated so that the metal surface is not partially exposed to a single battery 1. The exterior full face of a battery case 3 includes the side face and bottom part of the battery case. Thereby, even if electrolyte leaks from the single battery, a metallic battery case 3 and a cover plate or the like do not come into direct contact with the electrolyte, therefore, no short-circuiting occurs, no corrosion due electrolyte occurs, and the storage efficiency is better than the one by an insulation tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithium ion secondary battery, and more particularly to improving safety.

[0002]

2. Description of the Related Art In general, a lithium-on secondary battery is characterized by being excellent in high energy density, and is suitable for use as a power source for electronic devices such as mobile phones and a power source for electric vehicles.

By the way, the electrolytic solution of the lithium ion secondary battery may be any one that is stable in lithium and can dissolve a lithium salt, but an aprotic organic solvent having a large dielectric constant is preferable. For example, propylene carbonate, ethylene carbonate, tetrahydrofuran, diethyl carbonate, ethylmethyl carbonate, dimethyl carbonate, acetonitrile and the like.
Then, these solvents can be used alone or in an appropriate mixture.

Further, as the electrolyte, for example, a lithium salt which produces a stable anion such as lithium perchlorate, lithium borofluoride, lithium hexafluoroantimonate and lithium hexafluorophosphate is used.

As the positive electrode, lithium manganese oxide (LiMn ² O ⁴ ) or lithium cobalt oxide (LiC) is used.
Lithium metal oxides such as oO ² ) and lithium nickel oxide (LiNiO ² ) can be used. The negative electrode may be any material that can be doped with lithium and dedoped, and examples thereof include carbon materials such as artificial graphite, natural graphite, and coke, metal oxides, and metal sulfides.

As the separator, a microporous polyolefin film or a nonwoven fabric made of synthetic fiber or glass fiber is used. As the battery case and the lid plate for sealing the battery, stainless steel, aluminum or aluminum alloy, iron plated with nickel, and the like are used. The shape includes a cylindrical shape and a square shape.

As a lithium ion secondary battery, a positive electrode active material and a negative electrode active material are made into a paste, and then coated on a metal foil, rolled, cut into a predetermined size, and wound or laminated with a separator interposed therebetween. The plate group is housed in a battery case, the electrolytic solution is injected, and then sealed with a lid plate for assembly.

[0008]

By the way, when this type of battery is used as a power source for an electric vehicle or the like, it is necessary to connect dozens of large capacity single cells having a capacity of 50 Ah or more in series. Yes, it becomes a very high voltage assembled battery. For this reason, when the unit cell leaks, this electrolytic solution adheres to the external terminals of the battery, the battery case made of metal, the exposed conductive parts of the connection parts, etc., and these parts are short-circuited via the electrolytic solution. However, in a remarkable case, it is considered that a defect due to high voltage application occurs and lithium is electrodeposited. Therefore, in order to deal with such a problem, a method of coating the unit cell with an insulating tube such as polypropylene resin has been proposed.

However, in this method, the electrolytic solution enters the gap between the battery case and the insulating tube, and eventually the single cell is short-circuited via the electrolytic solution. Further, in the unit cell provided with the positive and negative terminals, when the electrolytic solution is accidentally leaked from between the terminal provided on the case cover plate and the cover plate, the insulating tube covers only the case side surface, There is a problem that a short circuit occurs between terminals via the leaked electrolyte.

That is, the object of the present invention is to
It is an object of the present invention to provide an assembled battery and a group battery that do not short-circuit a single cell through the electrolytic solution even if the electrolytic solution leaks, and have no problems due to high voltage application.

[0011]

A first aspect of the present invention is an assembled battery in which a single cell is a lithium ion secondary battery and a plurality of the single cells are connected in series or in parallel. The outer surfaces of the unit cell, the unit cell terminal portion, and the connection lead are entirely covered with a film of an insulating material.

According to a second aspect of the present invention, the unit cell is a lithium ion secondary battery, and a plurality of the unit cells are connected in series or in parallel, and the assembled battery is further connected in series or in parallel. In the group battery used as above, the outer surface of the connection lead between the assembled batteries is entirely covered with a film of an insulating material.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The assembled battery according to the present invention is a unit cell,
By covering the outer surfaces of the unit cell terminals and connection leads with an insulating material so that there are no exposed parts, even if the electrolyte leaks from the unit cell, a film of insulating material that covers the entire outer surface Since there is no exposed part, and unlike the insulating tube, an air layer is not formed between the battery case and the film, so the metal battery case and lid plate may come into direct contact with the electrolytic solution. Because there is no
It will not short circuit and will not be corroded by the electrolyte. And the storage efficiency is better than that using an insulating tube.

In the present invention, the coating film of the insulating material has a contact angle of 50 with respect to the electrolytic solution on the film or water infiltrated from the outside.
The above is desirable.

Therefore, the assembled battery according to the present invention also has water resistance, and can be used as a power source for driving on water. Will be available.

Further, in a group battery in which the assembled batteries are further connected in series or in parallel, the outer surfaces of the connection leads for connecting the assembled batteries are entirely covered with an insulating material,
The same effect as above can be obtained. In addition, at least the inner surface of the container accommodating the assembled battery may be entirely covered with an insulating material. If the storage container has a lid, at least the inner surface of the lid may be coated.

The term "terminal portion" as used in the present invention means a fixed component of the connection lead connected to the terminal when the connection lead and the terminal are fixedly connected by a fixed component (nut or the like). When parts are not used (welding etc.), it means a terminal. The connection lead means a connection lead between the unit cells, between the assembled batteries or / and between the assembled battery or the group battery and an external device.

[0018]

EXAMPLE A detailed description will be given based on a preferred example of the lithium ion secondary battery according to the present invention.

FIG. 1 is a view showing a single cell of a cylindrical lithium secondary battery having a diameter of 66 mm, a height of 200 mm and a battery capacity of 50 Ah.

Reference numeral 1 is a unit cell which is a cylindrical lithium ion secondary battery, 2 is an insulating material, 3 is a battery case, 4 is a cover plate,
Reference numeral 5 is an insulating packing, 6 is a positive electrode terminal, and 7 is a negative electrode terminal.

In this embodiment, the positive electrode and the negative electrode are wound with the separator interposed therebetween and inserted in the battery case 3. Then, after attaching the lead terminal and injecting the electrolytic solution, the lid plate 4 is sealed by laser welding.

The positive electrode is formed by mixing lithium cobalt oxide and acetylene black, which is a conductive agent, on both surfaces of an aluminum foil having a thickness of 0.03 mm, and depositing a paste.

The negative electrode is a 0.02 mm thick copper foil coated with natural graphite capable of being doped and dedoped with lithium on both sides.

The thickness of the separator is 0.035.
A polyethylene resin microporous membrane of mm was used. As an electrolytic solution, a solution obtained by dissolving lithium hexafluorophosphate in a mixed solvent of ethylene carbonate and diethyl carbonate at a ratio of 1 mol / l was used.

A coating of polyphenylene sulfide resin, which is an insulating coating, is applied to the unit cell 1 assembled as described above by spraying it on the entire exterior of the battery case 3 and the cover plate 4 to expose a part of the metal surface. It was completely covered and insulated so as not to. The entire outer surface of the battery case 3 includes not only the side surface of the battery case but also the bottom portion.

FIG. 2 shows a lithium secondary battery unit cell having a rectangular battery shape.

In FIG. 2, the external dimensions of the battery are 80 m wide.
A lithium ion secondary battery 8 having m, thickness of 70 mm, height of 240 mm, and capacity of 100 Ah. Like the cylindrical lithium ion secondary battery 1 of FIG. 1, an insulating paint 2 of polyphenylene sulfide resin is used to cover the battery case 3 and the lid. It was applied to the entire outer surface of the plate 4. In this case as well, the entire outer surface of the battery case 3 includes not only the side surface of the battery case but also the bottom portion.

In each of these batteries, battery 10
Spray the insulating paint 2 excluding the terminal part or the battery surface where the terminal is located, and connect the terminals with connecting leads and connect the output terminal of the assembled battery and the input terminal of the external device. Then, the insulating coating material 2 was spray-coated on the terminal portion and the connection lead to manufacture an assembled battery.

As described above, by covering all the outer surfaces of the unit cells, unit cell terminals, connecting leads between the unit cells and connecting leads with external equipment with the insulating material, there is no exposed portion and Unlike the insulating tube, since no air layer is formed between the battery case and the coating, even if the electrolyte leaks, no short circuit occurs. And the storage efficiency is better than that of the insulating tube.

In the examples, polyphenylene sulfide resin was used as the resin of the insulating paint, but in addition, polypropylene resin, polyethylene resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, polystyrene resin, silicone resin, Acrylic resin, vinyl resin, amino resin, or fluororesin may be used, and rubber-based paint such as styrene-butadiene copolymer may be used.
And, if it is electrolytic solution resistant, it is not limited to this.

Further, although the insulating material is applied by spraying in this embodiment, the means such as brush coating or dipping is not particularly limited, but from the viewpoint of work efficiency, the small battery is used. It is preferable to use dipping, and for large-scale spraying.

[0032]

EFFECTS OF THE INVENTION In the assembled battery according to the present invention, the outer surface of the unit cell, the terminal portion of the unit cell and the connecting lead are all covered with an insulating material so that there is no exposed portion, so that the electrolytic solution is removed from the unit cell. Even if liquid leaks, the coating of the insulating material covering the entire outer surface leaves no exposed portion, and unlike the insulating tube, an air layer is not formed between the battery case and the coating. Since the metal battery case and lid plate do not come into direct contact with the electrolytic solution, there is no short circuit and corrosion by the electrolytic solution does not occur. And the storage efficiency is better than that using an insulating tube.

Further, it is needless to say that the present invention can be applied to all the assembled batteries in which two or more unit cells are connected in series regardless of the size of the battery capacity. Since it also has water resistance, it can be used as a power source for driving on water.

In addition, in the group battery in which the assembled batteries are further connected in series or in parallel, the outer surfaces of the connection leads for connecting the assembled batteries are also entirely covered with an insulating material so that the same as the above. The effect is obtained. Therefore, the industrial value of the present invention is extremely large.

[Brief description of drawings]

FIG. 1 is an external view of a cylindrical lithium ion secondary battery showing a unit cell that constitutes an assembled battery according to the present invention.

FIG. 2 is an external view of a prismatic lithium ion secondary battery showing a unit cell that constitutes the assembled battery according to the present invention.

[Explanation of symbols]

 1 Cylindrical lithium ion secondary battery 2 Insulating paint 3 Battery case 4 Lid plate 5 Insulating packing 6 Positive electrode terminal 7 Negative electrode terminal 8 Rectangular lithium ion secondary battery

Claims (2)

[Claims] 1. An assembled battery in which the unit cell is a lithium-ion secondary battery and a plurality of the unit cells are connected in series or in parallel, and the outer surface of the unit cell, the unit cell terminal portion and the connection lead. The battery pack is characterized in that it is entirely covered with a film of an insulating material. 2. A group battery in which the unit cell is a lithium-ion secondary battery and a plurality of the unit cells are connected in series or in parallel and the assembled battery is further connected in series or in parallel. In the group battery, the outer surface of the connection lead between the assembled batteries is entirely covered with a film of an insulating material.