JPH11144586A - Thermal fuse for battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal fuse for a battery in which the performance of the thermal fuse is secured and inner fixing work is smoothly conducted by previously fixing a lead conductor of the thermal fuse to a circular insulating spacer interposed between the outer circumferential end of an explosion proof valve plate and the outer circumferential end of a positive electrode cover in a lithium ion secondary battery in which the thermal fuse is connected to between the explosion proof valve plate and the positive electrode cover. SOLUTION: A flat lead conductor is used in both lead conductors 12 of a thermal fuse body 1 housed between an explosion valve plate and a positive electrode cover within a sealed battery, the end 121 of one flat lead conductor is positioned on one surface of a circular insulating spacer 2 interposed between the outer circumferential end of the explosion proof valve plate and the outer circumferential end of the positive electrode cover, the end 122 of the other flat lead conductor is positioned on the other surface of the circular insulating spacer 2, and at least one of the flat lead conductors is fixed by fusion or with an adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature hue used internally in a sealed secondary battery such as a lithium ion battery.
Related to

[0002]

2. Description of the Related Art Recently, large-capacity batteries such as lithium ion secondary batteries have been used as power sources for portable electric devices and the like. In such a large-capacity battery, a considerably large current flows at the time of charging or discharging, and there is a fear that abnormal heat may be generated due to overcurrent at the time of charging or failure. Normally, a temperature fuse is used as a circuit protection element for protecting the device by preventing abnormal heating of the device. That is, the temperature fuse is connected in series to the equipment, and is thermally closely attached to the equipment so that the heat generated by the equipment can be efficiently sensed, and the temperature fuse is operated at a desired limit temperature of the equipment. The power supply to the device has been cut off. In the above battery, a positive electrode cover is arranged on an explosion-proof valve plate that operates when the electrolyte is at an abnormal internal pressure, and the outer peripheral end of the explosion-proof valve plate and the outer peripheral end of the positive electrode cover are interposed by packing at the upper end of the negative electrode can. The electrolyte in the negative electrode can is sealed by sealing the explosion-proof valve plate with the outer periphery of the positive electrode lid. A temperature fuse is accommodated in the fuse, and one lead conductor of the temperature fuse is sandwiched between the insulating spacer and the outer peripheral end of the explosion-proof valve plate, and the other lead of the same temperature fuse is held. It is known to attach a temperature fuse in series to a battery circuit by sandwiching a conductor between an insulating spacer and an outer peripheral end of a positive electrode cover (Japanese Patent Laid-Open No. 9-153355).
issue).

In such a temperature fuse for a battery, if the end of each lead conductor of the temperature fuse and each surface of the annular insulating spacer are fixed in advance, the temperature fuse can be mounted. Temperature fuse can be prevented from misalignment at the time of installation, the installation work can be made smoother, and the annular insulating spacer can be used to protect the temperature fuse mechanically during handling of the temperature fuse. It is a frame, which is advantageous because deformation of the lead conductor during temperature fuse transfer can be prevented.

[0004]

However, the outside diameter of the temperature fuse lead conductor is about 0.6 mmφ for a general-purpose product, and if an adhesive is used to fix the end of the lead conductor. Adhesive adheres to the entire periphery of the end of the lead conductor, and an adhesive film is easily formed on the surface of the end of the lead conductor. It is difficult to ensure reliable electrical conduction between the outer peripheral end of the valve plate or the outer peripheral end of the positive electrode lid. Further, when heat fusion is used to fix the end of the lead conductor, the heat at the time of fusion is transferred to the low melting point fusible alloy piece of the temperature fuse via the lead conductor and the temperature fuse is heated. There is a concern that the performance of the device may be deteriorated or damaged.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a temperature fuse which is provided between an explosion-proof valve plate and a positive electrode cover of a lithium ion secondary battery. A battery in which a temperature fuse lead conductor is fixed to the annular insulating spacer to be sandwiched in advance so that the temperature fuse performance can be ensured and the internal work can be performed smoothly. The purpose of the present invention is to provide a temperature fuse.

[0006]

SUMMARY OF THE INVENTION A temperature fuse for a battery according to the present invention is provided on both lead conductors of a temperature fuse body accommodated between an explosion-proof valve plate and a positive electrode cover in a sealed battery. A flat lead conductor (having a width of 1500 to 7100 μm and a thickness of 50 to 200 μm) is used. An annular insulating spacer sandwiched between the outer peripheral end of the explosion-proof valve plate and the outer peripheral end of the positive electrode cover. The end of the one flat lead conductor is positioned on one side, and the end of the other flat lead conductor is positioned on the other surface of the annular insulating spacer, and at least one is fixed by fusion or adhesive. This is a configuration characterized by the following.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a plan view showing an example of the temperature fuse according to the present invention, and FIG. 1B is a cross-sectional view taken along a line in FIG. In FIG. 1 (a) and FIG. 1 (b), reference numeral 1 denotes a temperature fuse body, and a pair of flat lead conductors 12, 12 (for example, copper foil or nickel) is formed on an insulating substrate 11, for example, a plastic film piece. (A foil or an aluminum foil) is exposed and fused from the back side to the front side, and the swelling heads are bridged by the low melting point fusible alloy pieces 13 to form the low melting point fusible alloy pieces 13. A flux 14 is applied to the insulating substrate 15, for example, a peripheral portion of a plastic cover film is fused to the insulating substrate 11 to seal the low melting point fusible alloy piece 13. Reference numeral 2 denotes an annular insulating spacer, which can be made of a plastic film (for example, polyethylene terephthalate, polyamide, polyimide, polyphenylene sulfide, etc.), a ceramic thin plate, or the like. The end 121 of one of the flat lead conductors 12 of the temperature fuse body 1 is placed in the annular insulating spacer 2.
On one side, the end 122 of the other flat lead conductor 12 is positioned on the other side of the annular insulating spacer 2, and one or both are bonded with an adhesive (a curable adhesive such as an adhesive or an epoxy resin, a hot adhesive). It is fixed by fusion (melt adhesive or the like) or fusion (contact of a heating block, ultrasonic welding, or the like). The flat lead conductor 12 has a thickness of 50 to 200 μm and a width of 7100 to 15
The cross-sectional area is approximately equal to the cross-sectional area of a circular line having a diameter of 600 to 670 μm. The thickness of the annular insulating spacer 2 is set to 50 to 500 μm.

In the above case, when the end of the flat lead conductor is fixed to the plane of the annular insulating spacer with an adhesive, the contact surface between the end of the flat lead conductor and the annular insulating spacer is large. It is possible to easily eliminate the adhesion of the adhesive to the surface of the end portion of the lead conductor by bonding at the spot, thereby preventing the formation of the adhesive film on the outer surface of the end portion of the lead conductor. Further, when the end of the flat lead conductor is fixed to the plane of the annular insulating spacer by heat fusion, the heat at the time of fusion is applied to the temperature fuse body due to the large surface area of the flat lead conductor. The transmission can be well suppressed by heat radiation on the surface of the flat lead conductor, and the low melting point fusible alloy piece of the temperature fuse body can be held safely.

In order to manufacture the temperature fuse for a battery according to the present invention, a flat lead conductor having a surplus length of the temperature fuse body is fixed to the plane of the annular insulating spacer by an adhesive or fusion. Then, the extra length 120 of the lead conductor can be trimmed together with the edge 20 of the annular insulating spacer 2 as shown in FIG.

FIG. 3 shows a battery incorporating a temperature fuse according to the present invention. In this battery, a spirally wound body a of a positive electrode 42 and a negative electrode 43 with a separator 41 interposed is accommodated in a negative electrode can 44 to electrically conduct the negative electrode 43 and the bottom surface of the negative electrode can 44, A positive electrode collector 45 is disposed at the upper end of the can 44 to electrically connect the positive electrode 42 to the collector 45, and the upper end 441 of the negative electrode can 44 is connected to the outside of the explosion-proof valve plate 46.
Packing 48 on the outer peripheral end of the
The central concave portion of the explosion-proof valve plate 46 is electrically connected to the positive electrode collecting electrode 49. A shows a temperature fuse according to the present invention.
6 in the space between the positive electrode lid 47 and the insulating spacer 2
Is sandwiched between the outer peripheral end of the explosion-proof valve plate 46 and the outer peripheral end of the positive electrode lid 47, and the upper end 441 of the negative electrode can is caulked to these outer peripheral ends via the packing 48.
The inside of the temperature fuse body 1 is sealed with an electrolytic solution, and the end 121 of one flat lead conductor of the temperature fuse body 1 is brought into contact with the outer peripheral end of the positive electrode lid 47, and the end of the other flat lead conductor. Reference numeral 122 contacts the outer peripheral end of the explosion-proof valve plate 46. The above flat leaf
Even when the lead conductor and the annular insulating spacer are fixed with an adhesive, no adhesive film is formed on the outer surface of the end of the flat lead conductor as described above. Electrical continuity can be secured. In this temperature fuse internal battery, when the temperature rises and the low melting point fusible alloy piece of the temperature fuse body 1 is heated to the melting point, the low melting point fusible alloy piece is melted and infinitely connected in series to the battery circuit. As a result, a large impedance is inserted, and the current is cut off. If the internal pressure rises abnormally, the operation of the explosion-proof valve plate 46 causes the positive electrode cover 47 to operate.
The gas is released from the gas vent hole 471, thereby preventing the explosion.

In the temperature fuse according to the present invention, the lead conductor of the temperature fuse body is fixed to the annular insulating spacer. The displacement can be prevented, and the temperature fuse body can be disposed at a predetermined position. Further, since the lead conductor is mechanically protected by using the annular insulating spacer as a protective frame, and deformation due to contact with another thin flat lead conductor can be prevented, the temperature fuse is opened to the battery. In the case where the lead conductor is internally mounted, the position of the lead conductor can be accurately positioned. Therefore, the workability of the internal work can be improved.

[0012]

According to the present invention, in a sealed battery such as a lithium ion secondary battery, the explosion-proof valve plate and the positive electrode cover are insulated by clamping an annular insulating spacer between the explosion-proof valve plate and the positive electrode cover. When the temperature fuse contained in the battery is inserted in series between the explosion-proof valve plate and the positive electrode cover, the lead conductor of the temperature fuse is fixed to the annular insulating spacer in advance without any trouble. Therefore, the temperature fuse can be internally attached to the battery with good workability without displacement of the temperature fuse body and deformation of the lead conductor. Good protection can also be achieved.

[Brief description of the drawings]

FIG. 1 is a drawing showing an example of a temperature fuse according to the present invention.

FIG. 2 is a view illustrating a method of manufacturing a temperature fuse according to the present invention.

FIG. 3 is a view showing a state in which a temperature fuse according to the present invention is installed inside a battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Temperature fuse body 12 Flat lead conductor 121 End of flat lead conductor 122 End of flat lead conductor 2 Annular insulating spacer 46 Explosion-proof valve plate 47 Positive electrode cover

Claims (3)

[Claims] 1. A flat lead conductor is used for both lead conductors of a temperature fuse body accommodated between an explosion-proof valve plate and a positive electrode lid in a sealed battery, and the explosion-proof valve plate has an outer peripheral end portion. One end of the above-mentioned flat lead conductor is provided on one side of the annular insulating spacer sandwiched between the outer peripheral end of the positive electrode lid, and the other flat lead is provided on the other side of the annular insulating spacer. A temperature fuse for a battery, wherein an end of a conductor is positioned and at least one of the ends is fixed by fusion. 2. A flat lead conductor is used for both lead conductors of a temperature fuse body accommodated between an explosion-proof valve plate and a positive electrode cover in a sealed battery, and the explosion-proof valve plate has an outer peripheral end. One end of the above-mentioned flat lead conductor is provided on one side of the annular insulating spacer sandwiched between the outer peripheral end of the positive electrode lid, and the other flat lead is provided on the other side of the annular insulating spacer. A temperature fuse for a battery, wherein an end of a conductor is located and at least one of the ends is fixed with an adhesive. 3. The flat lead conductor has a width of 1500 to 7100.
3. The battery temperature fuse according to claim 1, wherein the temperature fuse has a thickness of 50 to 200 [mu] m.