JP3754794B2

JP3754794B2 - Temperature fuse and temperature fuse mounting structure for secondary battery

Info

Publication number: JP3754794B2
Application number: JP09482597A
Authority: JP
Inventors: 智宏丹羽; 和男有山
Original assignee: Uchihashi Estec Co Ltd
Current assignee: Uchihashi Estec Co Ltd
Priority date: 1997-03-29
Filing date: 1997-03-29
Publication date: 2006-03-15
Anticipated expiration: 2017-03-29
Also published as: JPH10275547A

Description

【０００１】
【発明の属する技術分野】
本発明は温度ヒュ−ズ、特に密閉型二次電池に取り付けて使用する温度ヒュ−ズに関するものである。
【０００２】
【従来の技術】
近来、携帯用電子機器等の電源として、リチウムイオン電池、ニッケル水素電池等の大容量のものが多く使用されつつある。
図４は、これら二次電池の一例を示し、セパレ−タｓを介した正極ｐと負極ｎとのスパイラル巻回体Ｅを負極缶５１’に収容して負極ｎと負極缶５１’の底面とを電気的に導通し、負極缶５１’の上端内に正極集電極５３’を配設して正極ｐをこの集電極５３’に電気的に導通し、負極缶５１’の上端に安全弁５２’及びガス放出孔５４１’付き正極蓋５４’をガスケット５５’を介して封着し、安全弁５２’の中央凹部５２１’を正極集電極５３’に電気的に導通してある。
而して、異常な内圧上昇時、安全弁５２’が開放されて正極蓋５４’のガス放出孔５４１’からガスが放出されると共に安全弁５２’と正極集電極５３’との電気的導通が遮断される。
【０００３】
上記のリチウムイオン電池、ニッケル水素電池等においては、容量が大きく、充電時や放電時に相当に大きな電流が流れ、充電器や本体機器の故障時には、過電流が流れて異常発熱が惹起されることがある。
従来、かかる異常発熱に対し、二次電池に温度ヒュ−ズを取り付けておき、その異常発熱時に温度ヒュ−ズを溶断作動させ、上記安全弁の作動を待つまでもなく、充電または放電を停止させることが公知である。この場合、二次電池の電解液の放出・飛散を防止でき、周囲の電解液汚損を回避できる有利性がある。
【０００４】
【発明が解決しようとする課題】
しかしながら、従来においては、温度ヒュ−ズを二次電池の陰極缶の外面に取り付けており、二次電池の収納空間を大きくせざるを得ず、携帯電子機器の小型化に不利である。
【０００５】
本発明の目的は、二次電池の収容空間を増大させることなく二次電池に取付け得る温度ヒュ−ズ及び二次電池における温度ヒュ−ズの取付け構造を提供することにある。
【０００６】
【課題を解決するための手段】
本発明に係る二次電池における温度ヒュ−ズの取付け構造は、扁平な環状絶縁ケースの両面に周方向に異なる位置において、環状絶縁ケース内に臨んで電極が設けられ、これら電極間に低融点可溶金属線が接続され、低融点可溶合金線にフラックスが塗布された温度ヒュ−ズが、二次電池の安全弁周囲端部と正極蓋周囲端部との間に挾持されてなることを特徴とする。
【０００７】
【発明の実施の形態】
以下、図面を参照しつつ本発明の実施の形態について説明する。
図１の（イ）は本発明に係る温度ヒュ−ズの一例を示す図面、図１の（ロ）は図１の（イ）におけるロ−ロ断面図、図１の（ハ）は図１の（イ）におけるハ−ハ断面図、図１の（ニ）は図１の（イ）におけるニ−ニ断面図である。
図１の（イ）乃至図１の（ニ）において、１は扁平な環状絶縁ケ−スであり、図示のものでは、内側環状絶縁スペ−サ１１と外側環状絶縁スペ−サ１２と上下の絶縁プレ−ト１３，１４とが接着剤や融着により一体化されている。２１，２２は環状絶縁ケ−ス１の上下面に周方向に異なる位置において固設された電極であり、内側突出部を備えている。３は環状絶縁ケ−ス１内に収容された平型の低融点可溶合金線であり、両端のそれぞれが各電極２１，２２の突出部に溶接等により接合されている。４は低融点可溶合金線に塗布されたフラックスである。
上記環状絶縁ケ−ス１には、プラスチック（例えば、ポリエチレンテレフタレ−ト）やセラミックスを使用することができる。
上記電極２１，２２には、図２に示すように、環状絶縁ケ−スの上下絶縁プレ−ト１３，１４の全面を覆うものを使用することもできる。
【０００８】
上記温度ヒュ−ズを製作するには、上下の各絶縁プレ−トに孔を設け、この孔に電極を固着し、下側の絶縁プレ−ト上に内側環状絶縁スペ−サ及び外側環状絶縁スペ−サを配し、これらスペ−サ間の空間に低融点可溶合金線を配し、この低融点可溶合金線にフラックスを塗布し、更に上側の絶縁プレ−トを配し、各絶縁プレ−トと内側環状絶縁スペ−サ及び外側環状絶縁スペ−サとの間を接着剤または融着により接着し、各電極と低融点可溶合金線との間を溶接等（抵抗溶接やレ−ザ溶接等）により接合する方法を用いることができる。
【０００９】
図３は上記温度ヒュ−ズの二次電池における取付け構造を示している。
図３において、５１は負極缶である。５２は金属製安全弁（板厚みの途中まで切れ目を入れた放圧板を含む）であり、中央の凹部５２１が正極集電極５３に電気的に接触されている。５４は金属製正極蓋であり、ガス放出孔５４１を備えている。
Ａは上記の温度ヒュ−ズを示し、安全弁５２の周囲端部と正極蓋５４の周囲端部との間に挾まれ、安全弁５２と温度ヒュ−ズＡ及び正極蓋５４の周囲端部に負極缶５１の上端開口がガスケット５５を介してかしめ加工され、温度ヒュ−ズＡの各電極２１，２２が正極蓋５４及び安全弁５３に電気的に導通されている。
上記において、温度ヒュ−ズの環状絶縁ケ−スの輪郭形状は負極缶の内側形状に応じ、円形、四角形、６角形、８角形等にされる。
【００１０】
本発明に係る温度ヒュ−ズが取り付けられる二次電池は、リチウムイオン電池、ニッケル水素電池等の容量の大きい二次電池であり、充電時や放電時に相当に大きな電流が流れ、充電器や本体機器の故障時には、過電流が流れて異常発熱することがある。この場合、温度ヒュ−ズの低融点可溶合金片が溶融され、低融点可溶合金片よりも融点が低く既に溶融しているフラックスの作用を受けつつ溶融合金が電極に向け濡れで引張られて球状化分断され、その分断でア−クが生じ、そのア−ク熱でフラックスが気化され、温度ヒュ−ズ内に内圧が発生される。
而るに、本発明に係る温度ヒュ−ズにおいて、低融点可溶合金線の長さは上記球状化分断を生じさせ得る長さであればよく、その長さは環状絶縁ケ−スの環状長さよりも短尺であり、環状絶縁ケ−ス内空間におけるフラックスで占められていないスペ−スａとフラックスで占められているスペ−スｂとの比ａ／ｂを充分に大きくできるから、上記フラックスの気化により発生する内圧を充分に低く抑え得、温度ヒュ−ズの破裂を確実に防止できる。
【００１１】
本発明に係る二次電池における温度ヒュ−ズの取付け構造においては、寸法的に、安全弁と正極蓋との間に温度ヒュ−ズの環状絶縁ケ−スを挾むだけの隔離寸法をとるだけで済み、二次電池の収納スペ−スの増大を僅小にとどめ得る。
また、温度ヒュ−ズの絶縁ケ−スが環状であり、温度ヒュ−ズを二次電池の安全弁とガス放出孔付き正極蓋とによる放圧機構を保持して取付けてあるから、二次電池の内圧が不測的に上昇しても、安全弁の作動により正極蓋のガス放出孔からガスを放出させて二次電池の爆裂を防止できる。
【００１２】
【発明の効果】
本発明に係る温度ヒュ−ズにおいては、二次電池の安全弁周囲端部と正極蓋周囲端部との間に挾んで二次電池に取付け得、二次電池の収容空間を殆ど増大させることが無く、携帯電子機器の小型性をよく保持できる。
また、環状絶縁ケ−ス内にフラックス量に対し充分に大きな空間を保有させてあるから、温度ヒュ−ズの作動時、フラックスの気化による内圧上昇をよく抑制でき、温度ヒュ−ズを良好に作動させ得る。更に、環状絶縁ケ−スの絶縁ケ−スを環状にして二次電池の放圧機構を維持させてあるから、二次電池の不測の内圧上昇に対し安全弁を確実に作動させ得る。
【図面の簡単な説明】
【図１】本発明に係る温度ヒュ−ズの一実施例を示す図面である。
【図２】本発明に係る温度ヒュ−ズの別実施例の要部を示す図面である。
【図３】本発明に係る二次電池における温度ヒュ−ズの取付け構造の一実施例を示す図面である。
【図４】二次電池を示す図面である。
【符号の説明】
１扁平な環状絶縁ケ−ス
２１電極
２２電極
３低融点可溶合金線
４フラックス
Ａ温度ヒュ−ズ
５２安全弁
５４正極蓋
５５ガスケット[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a temperature fuse, and more particularly to a temperature fuse used by being attached to a sealed secondary battery.
[0002]
[Prior art]
Recently, a large-capacity battery such as a lithium ion battery or a nickel metal hydride battery is being used as a power source for portable electronic devices.
FIG. 4 shows an example of these secondary batteries, in which a spiral wound body E of a positive electrode p and a negative electrode n through a separator s is accommodated in a negative electrode can 51 ′, and the bottom surfaces of the negative electrode n and the negative electrode can 51 ′. Are connected to each other, a positive electrode collecting electrode 53 ′ is disposed in the upper end of the negative electrode can 51 ′, and the positive electrode p is electrically connected to the collecting electrode 53 ′, and a safety valve 52 is connected to the upper end of the negative electrode can 51 ′. A positive electrode lid 54 'with a gas discharge hole 541' is sealed through a gasket 55 ', and the central recess 521' of the safety valve 52 'is electrically connected to the positive electrode collector electrode 53'.
Thus, when the internal pressure rises abnormally, the safety valve 52 ′ is opened, gas is released from the gas discharge hole 541 ′ of the positive electrode lid 54 ′, and electrical conduction between the safety valve 52 ′ and the positive electrode collector electrode 53 ′ is interrupted. Is done.
[0003]
The above lithium ion battery, nickel metal hydride battery, etc. have a large capacity, a considerably large current flows at the time of charging or discharging, and an overcurrent flows at the time of failure of the charger or main device, causing abnormal heat generation. There is.
Conventionally, in response to such abnormal heat generation, a temperature fuse is attached to the secondary battery, and when the abnormal heat generation occurs, the temperature fuse is blown to stop charging or discharging without waiting for the operation of the safety valve. It is known. In this case, there is an advantage that the discharge and scattering of the electrolyte solution of the secondary battery can be prevented, and the surrounding electrolyte solution can be avoided.
[0004]
[Problems to be solved by the invention]
However, conventionally, the temperature fuse is attached to the outer surface of the cathode can of the secondary battery, and the storage space for the secondary battery has to be increased, which is disadvantageous for miniaturization of portable electronic devices.
[0005]
An object of the present invention is to provide a temperature fuse that can be attached to a secondary battery without increasing the accommodation space of the secondary battery and a structure for attaching the temperature fuse in the secondary battery.
[0006]
[Means for Solving the Problems]
The temperature fuse mounting structure in the secondary battery according to the present invention is such that electrodes are provided on both sides of a flat annular insulating case at different positions in the circumferential direction, facing the annular insulating case, and a low melting point between these electrodes. A temperature fuse, in which a fusible metal wire is connected and a flux is applied to a low melting point fusible alloy wire, is sandwiched between the peripheral end of the safety valve of the secondary battery and the peripheral end of the positive electrode lid. Features.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1A is a drawing showing an example of a temperature fuse according to the present invention, FIG. 1B is a cross-sectional view of FIG. 1A, and FIG. (A) is a cross-sectional view taken along the line A, and (d) in FIG. 1 is a cross-sectional view taken along the line (a) in FIG.
1 (a) to 1 (d), reference numeral 1 denotes a flat annular insulating case. In the illustrated case, the inner annular insulating spacer 11 and the outer annular insulating spacer 12 are The insulating plates 13 and 14 are integrated by an adhesive or fusion. Reference numerals 21 and 22 denote electrodes fixed on the upper and lower surfaces of the annular insulating case 1 at different positions in the circumferential direction, and have inner protrusions. Reference numeral 3 denotes a flat low-melting-point soluble alloy wire housed in the annular insulating case 1, and both ends are joined to the protruding portions of the electrodes 21 and 22 by welding or the like. 4 is a flux applied to the low melting point soluble alloy wire.
For the annular insulating case 1, plastic (for example, polyethylene terephthalate) or ceramics can be used.
As the electrodes 21 and 22, as shown in FIG. 2, it is possible to use an electrode that covers the entire upper and lower insulating plates 13 and 14 of an annular insulating case.
[0008]
To manufacture the temperature fuse, holes are formed in the upper and lower insulating plates, electrodes are fixed to the holes, and the inner annular insulating spacer and the outer annular insulating are formed on the lower insulating plate. A spacer is arranged, a low melting point soluble alloy wire is arranged in the space between the spacers, a flux is applied to the low melting point soluble alloy wire, and an upper insulating plate is arranged. The insulating plate is bonded to the inner annular insulating spacer and the outer annular insulating spacer by an adhesive or fusion, and welding between each electrode and the low melting point soluble alloy wire (resistance welding or A method of joining by laser welding or the like can be used.
[0009]
FIG. 3 shows a mounting structure in the above-mentioned temperature fuse secondary battery.
In FIG. 3, 51 is a negative electrode can. Reference numeral 52 denotes a metal safety valve (including a pressure relief plate with a cut in the middle of the plate thickness), and the central recess 521 is in electrical contact with the positive electrode collector electrode 53. Reference numeral 54 denotes a metal positive electrode lid provided with a gas discharge hole 541.
A indicates the above temperature fuse, and is sandwiched between the peripheral end of the safety valve 52 and the peripheral end of the positive electrode lid 54, and the negative electrode is disposed at the peripheral end of the safety valve 52, the temperature fuse A and the positive electrode lid 54. The upper end opening of the can 51 is caulked through a gasket 55, and the electrodes 21 and 22 of the temperature fuse A are electrically connected to the positive electrode lid 54 and the safety valve 53.
In the above, the contour shape of the annular insulating case of the temperature fuse is made circular, quadrangular, hexagonal, octagonal, etc. according to the inner shape of the negative electrode can.
[0010]
The secondary battery to which the temperature fuse according to the present invention is attached is a secondary battery having a large capacity, such as a lithium ion battery or a nickel metal hydride battery, and a considerably large current flows during charging or discharging. When a device fails, overcurrent may flow and cause abnormal heat generation. In this case, the low-melting-point soluble alloy piece having a temperature fuse is melted, and the molten alloy is pulled toward the electrode by being wetted by the action of the already melted flux having a melting point lower than that of the low-melting-point soluble alloy piece. As a result, the arc is generated, and the arc is generated, and the flux is vaporized by the arc heat, and an internal pressure is generated in the temperature fuse.
Therefore, in the temperature fuse according to the present invention, the length of the low-melting-point soluble alloy wire may be any length that can cause the above-mentioned spheroidization, and the length thereof is the annular shape of the annular insulating case. Since the length a is shorter than the length and the ratio a / b between the space a not occupied by the flux in the space in the annular insulating case and the space b occupied by the flux can be sufficiently increased, The internal pressure generated by vaporization of the flux can be suppressed sufficiently low, and the temperature fuse can be reliably prevented from bursting.
[0011]
In the structure for attaching the temperature fuse in the secondary battery according to the present invention, the dimension is such that the isolation dimension is sufficient to hold the annular insulation case of the temperature fuse between the safety valve and the positive electrode cover. Thus, the increase in the storage space for the secondary battery can be minimized.
Further, since the insulation case of the temperature fuse is annular and the temperature fuse is attached while holding the pressure release mechanism by the safety valve of the secondary battery and the positive electrode lid with the gas discharge hole, the secondary battery Even if the internal pressure of the battery rises unexpectedly, the secondary battery can be prevented from exploding by releasing the gas from the gas discharge hole of the positive electrode lid by operating the safety valve.
[0012]
【The invention's effect】
In the temperature fuse according to the present invention, the secondary battery can be attached to the secondary battery by sandwiching it between the peripheral end portion of the safety valve and the peripheral end portion of the positive electrode lid, thereby substantially increasing the storage space of the secondary battery. The portable electronic device can be kept small in size.
Also, since the annular insulation case has a sufficiently large space with respect to the amount of flux, during operation of the temperature fuse, an increase in internal pressure due to vaporization of the flux can be well suppressed, and the temperature fuse is improved. Can be activated. Further, since the pressure release mechanism of the secondary battery is maintained by making the insulation case of the annular insulation case annular, the safety valve can be reliably operated against an unexpected increase in internal pressure of the secondary battery.
[Brief description of the drawings]
FIG. 1 is a view showing an embodiment of a temperature fuse according to the present invention.
FIG. 2 is a view showing a main part of another embodiment of a temperature fuse according to the present invention.
FIG. 3 is a view showing an embodiment of a temperature fuse mounting structure in a secondary battery according to the present invention.
FIG. 4 is a view showing a secondary battery.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Flat annular insulation case 21 Electrode 22 Electrode 3 Low melting-point soluble alloy wire 4 Flux A Temperature fuse 52 Safety valve 54 Positive electrode lid 55 Gasket

Claims

Electrodes are provided on both sides of the flat annular insulation case at different positions in the circumferential direction, facing the inside of the annular insulation case, a low melting point soluble metal wire is connected between these electrodes, and flux is applied to the low melting point soluble alloy wire. A structure for attaching a temperature fuse in a secondary battery, wherein the applied temperature fuse is sandwiched between a peripheral end portion of a safety valve of the secondary battery and a peripheral end portion of a positive electrode lid .

A temperature fuse used in a structure for mounting a temperature fuse in a secondary battery according to claim 1 , wherein electrodes are provided facing both sides of the flat annular insulating case at different positions in the circumferential direction. A temperature fuse characterized in that a low melting point soluble metal wire is connected between these electrodes, and a flux is applied to the low melting point soluble alloy wire.