JPH11144587A - Thermal fuse for battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the highly sensitive operation of a thermal fuse by surely, thermally bringing a lead conductor of the thermal fuse into contact with an explosion proof valve plate in the optimum condition when the thermal fuse is fixed to between the explosion proof vale plate and a positive electrode cover in a lithium ion secondary battery. SOLUTION: A thermal fuse is constituted with a thermal fuse main body having a pair of lead conductors 11, 12 housed between an explosion proof valve plate and a positive electrode cover, and 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 111 of one lead conductor 11 is positioned on one surface of the circular insulating spacer 2, the end 121 of the other lead conductor 12 is positioned on the other surface of the circular insulating spacer 2, and at least one of the lead conductors is fixed.

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).

[0003] The normal heat-sensitive path in the temperature fuse is divided into two paths: a path from the body of the temperature fuse to the low melting point fusible alloy piece and a path from the lead conductor to the low melting point fusible alloy piece. However, in the above structure for mounting the temperature fuse in the battery, the temperature fuse is floating from the explosion-proof valve plate, and little heat can be expected through the body. Heat is mainly transmitted through conductors. However, in the above-described structure for mounting the temperature fuse in the battery, the position of the temperature fuse during the mounting operation is unstable, and the position of the temperature fuse is likely to move, so that the explosion-proof valve plate and the lead conductor are connected to each other. The thermal contact state, especially the variation of the contact area is inevitable, and the contact area is too small to deteriorate the heat transfer characteristic to the low melting point fusible alloy piece, so that the battery may not be sufficiently protected.

SUMMARY OF THE INVENTION An object of the present invention is to provide a temperature fuse internally between an explosion-proof valve plate and a positive electrode cover of a lithium ion secondary battery, by connecting a lead conductor of the temperature fuse with the explosion-proof valve plate. The purpose of the present invention is to ensure that the temperature fuse is in thermal contact in an optimum condition to ensure a highly sensitive operation of the temperature fuse.

[0005]

According to one aspect of the present invention, there is provided a temperature fuse for a battery having a pair of lead conductors housed between an explosion-proof valve plate and a positive electrode cover in a sealed battery. A main body, and an annular insulating spacer sandwiched between an outer peripheral end of the explosion-proof valve plate and an outer peripheral end of the positive electrode cover. One end of the one lead conductor is provided on one surface of the annular insulating spacer. The end of the other lead conductor is positioned on the other surface of the annular insulating spacer, and at least one of the ends is fixed. Another temperature fuse for a battery according to the present invention includes a temperature fuse body having a pair of lead conductors housed between an explosion-proof valve plate and a positive electrode cover in a sealed battery, and an outer periphery of the explosion-proof valve plate. An annular insulating spacer sandwiched between the end and the outer peripheral edge of the positive electrode lid; a notch groove for positioning the temperature fuse body is provided on the inner periphery of the annular insulating spacer; Is fitted in the notch groove.

[0006]

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. 1A and FIG. 1B, reference numeral 1 denotes a temperature fuse main body, which has a pair of lead conductors 11 and 12.
Reference numeral 2 denotes an annular insulating spacer, which is a plastic film (for example, polyethylene terephthalate, polyamide,
Polyimide, polyphenylene sulfide, etc.), a ceramic thin plate or the like can be used. The temperature fuse body 1 is placed in the annular insulating spacer 2 so as to be centered with respect to each other.
End 11 of one lead conductor 11 of temperature fuse body 1
1 on one surface of the annular insulating spacer 2 and the other lead conductor 1
2 is positioned on the other surface of the annular insulating spacer 2, and one or both of them is bonded (adhesive, curable adhesive such as epoxy resin, hot melt adhesive, etc.) or fused (heating block). Abutment or ultrasonic welding).

FIG. 2A shows the temperature fuse body.
As shown in FIG. 1, a low melting point fusible alloy piece 10 is bridged between a pair of round wire lead conductors 11 and 12, and the low melting point fusible alloy piece 1 is formed.
Then, a flux 13 is applied to the core, and a cylindrical insulator 14 such as a ceramic cylinder is inserted through the flux-coated low melting point fusible alloy piece, and each end of the cylindrical insulator 14 and each of the lead conductors 11 and 12 are connected. As shown in FIG. 2B, a pair of flat lead conductors 11 and 12 are formed on an insulating substrate 140 such as a plastic film piece. (For example, a copper foil, a nickel foil, or an aluminum foil), the swelling head is exposed to the surface from the back side and fused, and the swelling head is bridged with the low melting point fusible alloy piece 10 to form a bridge. Low melting point fusible alloy piece 1
Then, the flux 13 is applied to the insulating substrate 140, and the periphery of the insulating cover 150, for example, the plastic cover film is placed on the insulating substrate 140.
A substrate-type temperature fuse body or the like in which the low-melting-point fusible alloy piece 10 is sealed by fusing to the substrate can be used.

FIG. 3 shows a state in which the temperature fuse according to the present invention is incorporated in a battery. 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 conduct the positive electrode 42 to the collector 45, and the upper end 441 of the negative electrode can 44 is connected to the outer peripheral end of the explosion-proof valve plate 46 and the positive electrode cover 47. The outer peripheral end portion of the explosion-proof valve plate 46 is caulked through a packing 48 so that 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, in which the temperature fuse body 1 is housed in a space between the explosion-proof valve plate 46 and the positive electrode lid 47, and the insulating spacer 2 is an outer peripheral end of the explosion-proof valve plate 46. And the outer peripheral end of the positive electrode lid 47, and the packing 48 is attached to these outer peripheral ends.
The inside of the negative electrode can 44 is sealed against the electrolytic solution by caulking the upper end portion 441 of the negative electrode can through an electrode, and the end 111 of one of the lead conductors 11 of the temperature fuse body 1 is connected to the explosion-proof valve plate 4.
6 and the end 1 of the other lead conductor 12
21 is in contact with the outer peripheral end of the positive electrode lid 47.

If the battery inside the temperature fuse generates abnormal heat, the heat generated by the battery will be transferred to the explosion-proof valve plate 45 and one of the lead conductors 1.
1 is transmitted to the low-melting-point fusible alloy piece in the temperature fuse body 1 through the contact portion with the one and the one lead conductor 11, and is infinitely connected in series with the battery circuit by fusing the low-melting-point fusible alloy piece. Is inserted and the energization is cut off. If the internal pressure rises abnormally, the operation of the explosion-proof valve plate 46 activates the positive electrode cover 4.
The gas is released from the gas vent hole 471 of 7 to prevent explosion. In the temperature fuse according to the present invention, the lead conductors 11, 12 are fixed to the annular insulating spacer 2,
An annular insulating spacer 2 is always positioned concentrically with the battery, and a temperature fuse body 1 is attached to the annular insulating spacer 2.
Is fixed, the temperature fuse body 1 is always installed at a fixed position with respect to the center of the battery, and the fixed position is such that the contact area between the explosion-proof valve plate 45 and the lead conductor 11 is maximized. With such a setting, the low melting point fusible alloy piece can be blown with high sensitivity.

FIG. 4 shows another battery temperature heater according to the present invention.
FIG. In this battery temperature fuse, the inner circumference of the annular insulating spacer 2 is separated by 180 °.
Notch grooves 21 and 21 are formed at two places, and both ends of the insulating cylinder of the cylindrical temperature fuse body 1 are fitted into the respective notch grooves 21 so that the temperature fuse body 1 is at the center of the annular insulating spacer 2. It is positioned at a point symmetric position with respect to. If the notch groove 21 can position the cylindrical temperature fuse body 1,
It can also be a place. Also in this battery temperature fuse, if the temperature fuse body is positioned in the annular insulating spacer, the contact area between the explosion-proof valve plate and the lead conductor is set to be maximum. Further, the low melting point fusible alloy piece can be blown with high sensitivity. In the temperature fuse shown in FIG. 4, between one surface of the annular insulating spacer 2 and the end 111 of one of the lead conductors 11, and between the annular insulating spacer 2 and the same.
The other surface and the end 121 of the other lead conductor 12 may be non-fixed or fixed, but if at least one is fixed, it is convenient for transferring and storing the temperature fuse. is there.

In the present invention, the outer shape of the annular insulating spacer is set according to the outer shape of the battery, and may be a round shape or a square shape.

[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 is inserted in series between the explosion-proof valve plate and the positive electrode lid, thermal contact between the explosion-proof valve plate and one end of the lead conductor of the temperature fuse body It is possible to ensure that the state is a certain optimum state, and it is possible to guarantee high sensitivity protection of the battery by the internal temperature fuse.

[Brief description of the drawings]

FIG. 1 is a drawing showing an example of a temperature fuse according to claim 1;

FIG. 2 is a view showing a different temperature fuse body used in 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.

FIG. 4 is a drawing showing an example of a temperature fuse according to claim 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Temperature fuse main body 11 Lead conductor 12 Lead conductor 111 End of lead conductor 121 End of lead conductor 2 Annular insulating spacer 21 Notch groove 46 Explosion-proof valve plate 47 Positive electrode cover

Claims (3)

[Claims] 1. A temperature fuse body having a pair of lead conductors housed between an explosion-proof valve plate and a positive electrode cover in a sealed battery, an outer peripheral end of an explosion-proof valve plate and an outer peripheral end of a positive electrode cover. An annular insulating spacer interposed between the ends of the one lead conductor on one side of the annular insulating spacer and the other end on the other side of the annular insulating spacer. A temperature fuse for a battery, wherein an end of a lead conductor is located and at least one of the ends is fixed. 2. A temperature fuse body having a pair of lead conductors housed between an explosion-proof valve plate and a positive electrode cover in a sealed battery, an outer peripheral end of the explosion-proof valve plate and an outer peripheral end of the positive electrode cover. An annular insulating spacer sandwiched between the annular insulating spacers. A notch groove for positioning the temperature fuse body is provided on the inner periphery of the annular insulating spacer, and the temperature fuse body is fitted into the notched groove. Characteristic temperature fuse for batteries. 3. An end of one lead conductor is located on one surface of the annular insulating spacer, and an end of the other lead conductor is located on the other surface of the annular insulating spacer. 3. The battery temperature fuse according to claim 2, which is fixed.