JP2000306556A - Framed battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure safety by improving rigidity of a battery using a film for an exterior body without deteriorating the advantages of high energy density and low manufacturing costs of the battery using the film for the exterior body. SOLUTION: This battery has a structure in which a power generating element is sealed by joining the peripheral part by using an exterior film. A frame body having a window and a terminal to be fitted to the thick part of the battery is connected to the thin part facing the joining part of the exterior film of the battery peripheral part. A recessed part to be fitted to the thin part of the battery peripheral part is formed on the joining part of the frame body to the 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 power generation element is sealed by using a laminate film for an exterior body, and from a bent portion of a thin portion corresponding to a joint portion of the exterior film and a frame of the thin portion. It is intended to prevent peeling of the terminal and deformation of the terminal.

[0002]

2. Description of the Related Art Since a lithium ion battery has a high energy density, it is widely used as a power supply for a portable terminal, and further development of higher capacity and thinner is required.

Comparing the energy densities of various small secondary batteries used for the power supply of portable equipment, lead batteries have a power density of 20 to 40 Wh / kg, 50 to 100 Wh / l,
40 to 50 Wh / kg for nickel cadmium battery, 1
30 to 200 Wh / l, 50 to 6 for nickel-metal hydride battery
0 Wh / kg, 250 to 300 Wh / l, 90 to 110 Wh / kg, 250 to 300 W for lithium ion batteries
h / l.

As a configuration of the small secondary battery, there are a cylindrical battery in which wound electrode groups are housed in a cylindrical case, and a rectangular battery in which flat electrode plates are stacked and housed in a rectangular case. These cases are formed of a metal container to provide strength, the production cost is high, and it is not easy to reduce the weight.

As a means for providing a cheaper and lighter compact secondary battery, a power generating element is laminated in a polyethylene sheet or an aluminum sheet and stored in a bag-like body made of a film member having non-gas permeability. One that has been joined and sealed by welding or the like has been proposed. As such a secondary battery, for example, as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 60-162362, a flat electrode group is sealed from the inside with a laminate made of a heat-sensitive adhesive layer, an aluminum foil and a polymer film. A metal vapor-deposited film serving as a lead body is formed on the heat-sensitive layer of the laminate film, and one end of the metal vapor-deposited film is brought into contact with an electrode terminal to seal the power generation element with the laminate film. As disclosed in US Pat. No. 206157, there is a method in which a flat plate group is inserted into a tubular laminated film member, and both ends are heat-sealed and sealed. In a battery using a laminate film for such an exterior body, the exterior film is poor in rigidity and easily deformed when an external force is applied. For this reason, the degree of freedom of the shape increases, but excessive deformation destroys the internal structure of the battery due to the stress, and causes the active material to fall off and short-circuit. In particular, the thin-walled portion, which is the bonding portion of the outer film around the battery, is easily deformed and easily subjected to external force. Further, since the terminal portion is also fixed only by the exterior film, the external force received by the terminal is transmitted to the power generating element inside the battery as it is, which may cause a short circuit.

Therefore, in order to ensure the safety against the deformation of the battery as described above, a device such as using an outer container has been devised. Further, Japanese Utility Model Application Laid-Open No. 63-42462 discloses a structure in which a frame body fitted to a thick part is joined to a thin part which is a joint part of an exterior film.

However, the use of an outer container impairs the advantages of high energy density and low manufacturing cost of a battery using a film for the outer package. In addition, 63-4246
In No. 2, the advantage of using a film for the outer package is maintained, but since the terminals are fixed only to the outer film, the terminals may be deformed when the battery is attached or detached, resulting in poor contact or stress applied to the terminals. Is transmitted to the inside of the battery, and the power generating element inside the battery may be deformed to cause a short circuit. Further, since the frame is merely joined to the thin portion, the joint between the frame and the battery is likely to be exposed to an external impact, which causes peeling and falling off.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has been made in consideration of the above-mentioned problems. An object of the present invention is to increase the rigidity of a battery using a film for a body and to ensure safety.

[0009]

In order to solve the above-mentioned problems, the present invention relates to a battery having a structure in which a power generation element is sealed by joining an outer peripheral portion thereof using an exterior film. A battery with a frame in which a frame having a window and a terminal fitted to a thick portion of the battery is joined to a thin portion corresponding to a joint of the exterior film. Further, the present invention provides a battery with a frame, wherein a concave portion which fits into a thin portion around the battery is formed in a joint portion of the frame with the battery.

[0010] That is, by providing a frame in the periphery of the battery where external force is easily applied and stress due to deformation tends to be concentrated,
The battery is prevented from being deformed due to an external force such as a drop impact, and the terminal portion to which the most stress is applied when the battery is attached / detached is fixed to the frame to prevent the battery from being damaged when the battery is attached / detached.

Further, by providing a concave portion in the frame body to be fitted to the peripheral portion of the battery, the outermost peripheral portion of the joint between the battery and the frame body is protected, and peeling and falling off of the battery are prevented.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. However, the present invention is not limited to these embodiments, and can be implemented with appropriate changes within a scope that does not change the gist of the present invention.

(Invention) First, the components of the battery of the invention will be described. The positive electrode has a positive electrode active material of LiCoO ₂ 87
Parts by weight, a mixture of 8.5 parts by weight of artificial scaly graphite as a conductive additive and 1.5 parts by weight of acetylene black was mixed with 12% polyvinylidene fluoride / N as a binder.
-Methyl-2-pyrrolidone solution (25 parts by weight) was added and kneaded, and N-methyl-2-pyrrolidone (29 parts by weight) was added into a paste to form a paste having a thickness of 20 μm.
Was applied to an aluminum foil having a thickness of about 260 μm, dried, punched into an electrode shape, and pressed to a thickness of about 100 μm.

As the positive electrode active material, other lithium-containing transition metal oxides such as spinel-type lithium manganate (LiMn ₂ O ₄ ) and lithium nickelate can be used.

The anode has an interlayer distance d0 as an anode active material.
02 is 3.37%, and 94% by weight of fibrous artificial graphite having a crystallite size Lc of 360 ° is 12% as a binder.
A polyvinylidene fluoride / N-methyl-2-pyrrolidone solution (50 parts by weight) was added, kneaded, and N-methyl-2-pyrrolidone (24 parts by weight) was added to form a paste. About 210μ thick on copper foil
m, dried, punched into an electrode shape, and pressed to a thickness of about 105 μm.

As the negative electrode active material, other carbon materials such as mesocarbon microbeads, coke, and hard carbon can be used.

As the binder other than those described above, polytetrafluoroethylene, a rubber-based polymer, a mixture of these with a cellulose-based polymer, a copolymer mainly containing polyvinylidene fluoride, or the like can be used.

As an electrolyte, first, a Li: 2 mixed solution of ethylene carbonate and γ-butyrolactone was added to Li:
An electrolytic solution in which BF ₄ was dissolved to 1 mol / l was prepared. A polymer electrolyte precursor A was prepared by mixing 20% of a macromer which is a copolymer of ethylene oxide and propylene oxide with three acrylate groups added to the electrolyte. The polymer electrolyte precursor A was cured by electron beam irradiation to obtain a gelled polymer electrolyte A. A polymer electrolyte precursor B was prepared by mixing a monomer obtained by acrylate-forming an ethylene oxide adduct of bisphenol A having an average molecular weight of 500 with the electrolyte solution by 20%. The polymer electrolyte precursor B was vacuum-impregnated into the positive and negative electrodes and cured by electron beam irradiation to form a polymer electrolyte B in the electrode plate.

The electrolyte is not limited to the above, and LiPF ₆ , LiBF ₄ , LiBF ₄ , LiPF ₄ , Li
An electrolytic solution in which a supporting salt such as ClO ₄ or lithium perfluoroalkylsulfonic acid imide salt is dissolved, or a gel electrolyte of the electrolytic solution and a polymer such as polyethylene oxide, polyacrylonitrile, or polyvinylidene fluoride can be used. .

A 30 μm-thick polypropylene nonwoven fabric as a separator is impregnated with a polymer electrolyte precursor A, and is irradiated with an electron beam to obtain a 35 μm-thick.
A gel film was used. The separator is not particularly limited, and various separators such as a conventionally used microporous polyethylene membrane and a microporous polyvinylidene fluoride membrane can be used.

Next, the structure of the battery of the present invention will be described. FIG. 1 is a cross-sectional view showing an example of a battery in which the positive and negative electrodes and the separator are laminated in a flat plate shape and sealed with an exterior film (1). The configuration of the laminated electrode group (2) is not particularly limited either. The wound electrode group (3) in which the positive and negative electrodes and the separator shown in FIG. ) May be used. In addition, it is desirable that one of the exterior films (1) before sealing is formed with a mold for a housing portion of the power generation element by deep drawing.

The frame (5) shown in FIG. 3 uses a synthetic resin molded body. The resin used for the frame (5) is required to be lightweight and rigid. The outer periphery of the frame should be larger than the outer periphery of the battery,
At the center, there is a window (6) that fits into the battery thick part corresponding to the power generation element housing. The edge of the window (6) has a slope that matches the slope of the step at the boundary between the thick part and the thin part of the battery. The thickness of the frame (5) is equal to or greater than the thickness of the battery thick portion in order to prevent the battery surface from protruding from the frame. In order to prevent peeling and detachment of the battery from the frame (5), a concave portion (7) having a depth equal to or greater than the thin portion is provided on the bonding surface with the thin portion of the battery. In the terminal portion, a terminal groove (8) for preventing the terminal (9) (FIG. 4) and / or the positive / negative electrode lead (4) (FIG. 6) from protruding from the frame (5) is formed. did. Terminal (9) is FIG. 6A
As shown in the figure, it was fixed in the terminal groove (8).

FIG. 4 shows a framed battery in which a frame (5) having a concave portion (7), a window (6), a frame and terminals (9) is connected to the battery. FIG. 5 is a cross-sectional view taken along a broken line in FIG.

The connection between the frame (5) and the battery was performed by applying an adhesive to the binding portion of the frame (5) and bonding them together.
The bonding may be performed by using a hot-melt material at the bonding portion and performing fusion.

An electronic contact was obtained by spot welding the terminal (9) and the positive / negative electrode lead (4). As shown in FIG. 6B, the positive / negative lead (4) can be used as a terminal as it is.

(Comparative Example) A battery sealed in the same manner as in the present invention and provided with terminals and recesses for the frame body used in the present invention in a battery sealed with the outer film, and the junction of the outer film with the outer peripheral portion of the battery. A battery in which a frame having a window fitted to a thick part of the battery was connected to a thin part corresponding to the above was used as a comparative example.

Battery 2 with frame produced as described above
When 0 pieces were attached / detached to / from the device, the frequency of the deformation of the terminal, the deformation of the battery, and the frequency of detachment / attachment detachment from the frame were measured.
FIG. 7 shows the results.

As is apparent from FIG. 7, in the present invention, 10
Even if the battery was repeatedly attached and detached more than once, the terminal deformation and the battery detachment did not occur, whereas in the comparative example, all the batteries were 1%.
Terminal deformation and battery detachment were caused by attaching and detaching the battery within 0 times. Therefore, the effect of the present invention is remarkable.

[0029]

As is clear from the above description, the battery with frame according to the present invention, in a battery using a laminate film for the exterior, prevents the deformation of the terminals and the deformation of the battery at the time of loading and unloading, and the battery The industrial value is great because the loading and unloading has been simplified and the safety of the battery has been improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a battery in which a power generation element is sealed by an exterior film using a laminated electrode group.

FIG. 2 is a cross-sectional view of a battery in which a power generation element is sealed by an exterior film using a wound electrode group.

FIG. 3 is a perspective view of a frame of the framed battery according to the present invention.

FIG. 4 is a front view of the framed battery of the present invention.

FIG. 5 is a cross-sectional view of the framed battery of the present invention taken along the broken line in FIG.

FIG. 6 is an enlarged cross-sectional view of a terminal portion of the framed battery of the present invention.

FIG. 7 is a diagram showing the results of a loading / removing test.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 exterior film 2 laminated electrode group 3 wound electrode group 4 positive / negative electrode lead 5 frame 6 window 7 recess 8 terminal groove 9 terminal

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[Procedure amendment]

[Submission date] June 9, 1999 (1999.6.9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

Therefore, in order to ensure the safety against the deformation of the battery as described above, a device such as using an outer container has been devised. Also discloses that combines the frame to fit the thick portion on the thin portion is a joining portion of the casing films in real public Sho 63-42462.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

However, the use of an outer container impairs the advantages of high energy density and low manufacturing cost of a battery using a film for the outer package. In addition, Akira real public 63-4246
In No. 2, the advantage of using a film for the exterior body is maintained, but since the terminal is fixed only to the exterior film, the terminal is deformed when the battery is attached or detached, resulting in poor contact or stress applied to the terminal. Is transmitted to the inside of the battery, and the power generating element inside the battery may be deformed to cause a short circuit. Further, since the frame is merely joined to the thin portion, the joint between the frame and the battery is likely to be exposed to an external impact, which causes peeling and falling off.

Claims (2)

[Claims] 1. A battery having a structure in which a power generation element is sealed by joining the peripheral portions thereof using an exterior film, wherein a thin portion corresponding to the joining portion of the exterior film at the battery peripheral portion is provided on the battery. A framed battery in which a frame having a window and a terminal fitted into a thick portion is combined. 2. The battery with a frame according to claim 1, wherein a concave portion is formed in a joint portion of the frame body with the battery so as to fit into a thin portion around the battery.