JP3731380B2

JP3731380B2 - Thermal protector and battery pack using this thermal protector

Info

Publication number: JP3731380B2
Application number: JP10360499A
Authority: JP
Inventors: 彦治奥山; 泰孝堀部
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 1999-04-12
Filing date: 1999-04-12
Publication date: 2006-01-05
Anticipated expiration: 2019-04-12
Also published as: JP2000294099A

Description

【０００１】
【発明の属する技術分野】
本発明は、過熱・過電流による電気機器等の焼損を防ぐためのサーマルプロテクタと、それを収納した２次電池パックに関するものである。
【０００２】
【従来の技術】
自己復帰式サーマルプロテクタは、熱によって反転動作を行う熱応動素子を有する可動電極と、この可動電極に対向して設けられ、かつ可動電極と接離可能に設けられた固定電極とを備えており、機器の異常温度上昇や、過電流に対し、熱応動素子がその動作温度以上になると熱応動素子が反転動作して可動電極と固定電極との接点を開き、給電を遮断して機器を保護する。そして、電気機器の異常が取り除かれ、熱応動素子の温度が下がると、熱応動素子は再び反転動作を行い、給電を再開する。このように自己復帰式サーマルプロテクタは取り替え不要で電気機器の異常を検知させることができ、ヒューズとは異なる大きな利点を備えた安全素子の一つとして用いられる。
【０００３】
図９に示すように従来のサーマルプロテクタは、容器２５内に、樹脂ブロック２６に固定された固定電極支持部２７および熱応動素子支持部２８と、固定電極支持部２７の一端部に接続された固定電極２９と、熱応動素子支持部２８の一端部に接続された熱応動素子３０と、熱応動素子３０の一端部に設けられた可動電極３１とを備えている。固定電極支持部２７および熱応動素子支持部２８の他端部には、リード線３２がそれぞれ接続され、各々のリード線３２は容器２５から外部に導出している。なお、樹脂ブロック２６は、充填剤１５で容器２５内に固定されている。
【０００４】
【発明が解決しようとする課題】
このような従来の自己復帰型のサーマルプロテクタは、現在２次電池パックの分野において携帯電話等の比較的低電流容量の機器向けに使用されている。一方、電動工具等に代表される大電流容量の機器の場合、安全性の面から自己復帰型は適さず、一度動作した後は作業者の手動操作による復帰方式が要求されること、また許容される形状寸法に対して定格電流が過大であることなどから、これまで２次短絡に対する好適なサーマルプロテクタが存在せず、安全性の高いサーマルプロテクタが望まれてきた。
【０００５】
本発明は、このような問題を解決するためになされたもので、安全性の高い手動復帰方式サーマルプロテクタを提供することを目的とするものである。
【０００６】
【課題を解決するための手段】
本発明の請求項１に記載のサーマルプロテクタは、内面に被係止部を有する容器内に、固定電極と、可動電極と、前記固定電極に対して前記可動電極を接離させるプランジャーと、前記プランジャーの軸方向に配置された弾性体と、前記プランジャーに支持され、かつ前記容器の被係止部に係止される係止部を一端に有する弾性板と、湾曲反転動作によって前記容器の被係止部から前記弾性板の係止部を離脱させる熱応動素子とを備え、前記固定電極は一定距離をおいた第１および第２の固定電極からなり、かつ前記可動電極は一定距離をおいて導電性の板に固定された第１および第２の可動電極からなるとともに、前記第１および第２の固定電極と前記第１および第２の可動電極とはそれぞれ対を成して対向した双断型接点の形態をとり、前記熱応動素子の一部が前記導電性の板と前記弾性板とに挟まれており、電流経路は前記第１の固定電極、前記第１の可動電極、前記導電性の板、前記第２の可動電極、および前記第１の固定電極で形成され、前記弾性板の係止部が前記容器の被係止部から離脱するにともない、前記弾性体の伸長作用によって前記プランジャーを軸方向に移動させることにより、前記固定電極と前記可動電極との接触状態を解除して前記固定電極と前記可動電極とを離間させて前記電流経路を遮断し、この離間した状態を維持する構成を有している。
【０００７】
この構成により、機器の温度上昇に伴う熱応動素子の湾曲反転動作によって、弾性板が押し下げられ、弾性板の係止部が容器の被係止部から離脱する。このとき弾性体の伸長によってプランジャーが移動し、固定電極と可動電極との接触状態を解除して離間させ、回路を遮断する。
【０００８】
次に、機器の異常状態を除去した後、リセットボタンを弾性板の係止部と被係止部とが係止する位置まで押し戻してやれば再び固定電極と可動電極との前記接点が閉じて給電が可能となる。
【０００９】
請求項２に記載の発明は、請求項１記載のサーマルプロテクタにおいて、前記弾性体は、第１および第２のコイルばねからなり、前記第１および第２の固定電極は支持体内に一定距離をおいて固定され、かつ前記第１および第２の固定電極間に前記第１のコイルばねが前記支持体内に埋設され、前記第２のコイルばねは前記導電性の板を介して前記第１のコイルばねと対向して直列配置され前記プランジャーの一端部で支持されている構成を有している。
【００１０】
この構成により、第１のコイルばねの伸縮動作によって可動接点を形成した導電性の板の駆動による固定接点と可動接点の接離が可能となり、第２のコイルばねの収縮によって導電性の板に負荷をかけ固定接点と可動接点間に接圧を発生させることができる。
【００１１】
請求項３に記載の発明は、請求項１または２に記載のサーマルプロテクタにおいて、前記プランジャーが凸部を有するブロックに固定されており、前記凸部は前記容器外に導出され、前記固定電極と前記可動電極との離間状態を接触状態に復帰させるためのリセットボタンになっている構成を有している。
【００１２】
この構成により、固定電極と可動電極との接点の離間状態において、容器外に導出されたリセットボタンを押し戻すことで再び接点を接触状態に復帰させることができる。
【００１３】
請求項４に記載の発明は、請求項３記載のサーマルプロテクタにおいて、前記弾性板の係止部が形成されてない他端部は前記ブロックの一部に当接して支持されている構成を有している。
【００１４】
この構成により、前記弾性板の静止状態での安定性が増し、ひいては前記固定電極と可動電極との接点の接圧の安定化が実現できる。
【００１７】
請求項５に記載の発明は、請求項１ないし４のいずれか１項に記載のサーマルプロテクタにおいて、前記弾性板の係止部の端部が湾曲状である構成を有している。
【００１８】
この構成により、前記被係止部と前記係止部との摺動による耐摩耗性を向上させることができる。
【００１９】
請求項６に記載の発明は、請求項１ないし５のいずれか１項に記載のサーマルプロテクタにおいて、前記弾性板の係止部と前記容器の被係止部が樹脂または金属からなる構成を有している。
【００２０】
この構成により、前記被係止部と前記係止部との摺動による耐摩耗性を向上させることができる。
【００２１】
請求項７に記載の発明は、請求項３記載のサーマルプロテクタにおいて、前記リセットボタンが導出された側の一部に凹部または凸部が形成されている構成を有している。
【００２２】
この構成により、前記凹部または凸部を利用した嵌合によって前記サーマルプロテクタを任意の箇所に簡単に装着することができる。
【００２３】
請求項８に記載の電池パックは、複数の２次電池が収納された電池パック内に、請求項３または７に記載のサーマルプロテクタが電池回路に直列に接続され、前記サーマルプロテクタの前記固定電極と前記可動電極との離間状態を接触状態とするとともに、前記電池回路のオフ状態をオン状態とするリセットボタンが設置されている構成を有している。
【００２４】
この構成により、２次電池の２次短絡等の異常が発生した場合、固定電極と可動電極とが離間状態となり電池回路を遮断（オフ状態）することができる。この後リセットボタンを押し戻して固定電極と可動電極とを接触状態にすることで、電池回路を通電状態（オン状態）にでき、給電を再開することができる。
【００２５】
請求項９に記載の発明は、請求項８記載の電池パックにおいて、電池パック内面に凹凸部を形成し、この凹凸が請求項７記載のサーマルプロテクタの容器に形成された凹凸部と嵌合することで、前記サーマルプロテクタが前記電池パック内に保持されている構成を有している。
【００２６】
この構成により、電池パック内にワンタッチでサーマルプロテクタを装着することができる。
【００２７】
請求項１０に記載の発明は、請求項８または９に記載の電池パックにおいて、前記固定電極と前記可動電極とが接触状態では、前記リセットボタンの先端部が前記電池パックの外表面よりも内側に位置している構成を有している。
【００２８】
この構成により、電池パックを所定の機器に装着して使用する場合、サーマルプロテクタのリセットボタンが作業の支障とならないようにすることができる。
【００２９】
請求項１１に記載の発明は、請求項８ないし１０のいずれか１項に記載の電池パックについて、前記貫通孔に取付けられ、かつ前記リセットボタンを操作可能としたキャップを有する構成を有している。
【００３０】
この構成により、電池パックの貫通孔から侵入する恐れのある水分、ほこり等の電池パック内部の２次電池およびサーマルプロテクタに悪影響を及ぼす可能性がある因子から電池パックを保護することができる。
【００３１】
【発明の実施の形態】
図１に示すように本発明の第１の実施の形態であるサーマルプロテクタは、ＰＢＴ（ポリブチレンテレフタレート）などの樹脂などからなる絶縁性容器１の内部に、リセットボタン２を兼ねた樹脂ブロック３にアルミニウムなどの金属からなる板状のプランジャー４が、この容器１の中心軸と同方向に設けられている。プランジャー４の一端部には銅などの金属板５を介して、第１のコイルばね６と第２のコイルばね７とが容器１の中心軸と同軸方向に直列配置され、第２のコイルばね側には弾性を有する銅などの金属製板ばね８が配置されている。ここで、前記板ばねとしては弾性板であればよく、板ばねに限定されない。さらに、一端部が金属板５と板ばね８とに挟まれ、他端部が板ばね８を反転動作によって矢印Ａ方向へ押し下げる働きをもった導電性熱応動素子９が設けられている。また、板ばね８の一端部には、湾曲状に形成された係止部１０が設けられ、この係止部１０の一端部は容器１の内面の所定位置に形成された被係止部１１の段差部分に収められ、一方、係止部が形成されていない他端部は、Ｌ字状に延びた樹脂ブロック３の一端に当接して支持されている。金属板５の両端部には銀などからなる第１および第２の可動電極１２ａ，１２ｂがそれぞれ設けられている。また、接点に銀などを施した第１および第２の固定電極１３ａ，１３ｂの一端部は、樹脂などの絶縁性を有する支持体１４に固定され、他端部は容器１外に導出されている。そして、支持体１４の中心部に設けられた穴には第１のコイルばね６の一端部が埋設されている。第１および第２の可動電極１２ａ，１２ｂは第１および第２の固定電極１３ａ，１３ｂにそれぞれ接触しており、第２のコイルばね７のたわみによって第１および第２の可動電極１２ａ，１２ｂと第１および第２の固定電極１３ａ，１３ｂとの接点間に接触圧が発生し、接点は接触状態を保ち、これによって、固定電極１３ａの外部端部からの電流は、順に可動電極１２ａ、金属板５、可動電極１２ｂを通って固定電極１３ｂの外部端部へと流れる電流経路が形成される。ここで、電流は上記電流経路と逆方向に流れてもよい。なお、容器１は支持体１４と充填剤１５とで密閉されている。
【００３２】
次に、上記サーマルプロテクタの動作について説明する。
【００３３】
いま、過電流あるいは温度の過昇によって機器（図示せず）の温度が上昇すると、熱応動素子９が内側に反る湾曲動作をし、これによって板ばね８が、図１に示す矢印Ａのようにプランジャー４側に押し込まれていき、熱応動素子９の動作温度が所定温度に達して熱応動素子９の押し量が被係止部１１の段差幅を上回ると、板ばね８の係止部１０が被係止部１１から離脱する。この瞬間、図２に示すように、伸長方向に付勢されていた第１のコイルばね６および第２のコイルばね７が伸長し、金属板５とプランジャー４が伸長方向に移動するため、金属板５に取り付けられた第１および第２の可動電極１２ａ，１２ｂが第１および第２の固定電極１３ａ，１３ｂから離れて離間状態となり、接点を開いて電流経路を遮断する。その結果、第１のコイルばね６および第２のコイルばね７の伸長距離の和だけ樹脂ブロック３の端部すなわちリセットボタン２が容器１の外に突出する。
【００３４】
そして、サーマルプロテクタが動作した後は、機器の異常状態が除かれたことを確認し、リセットボタン２を係止部１０が被係止部１１に収まる位置まで押し戻してやれば、第１の固定電極１３ａと第１の可動電極１２ａ、および第２の固定電極１３ｂと第２の可動電極１２ｂがそれぞれ接触状態となり、接点が再び閉じて給電可能となる。
【００３５】
なお、熱応動素子９の湾曲動作を板ばね８に効率よく伝達するために、板ばね８に突起を設けてもよい。また、熱応動素子９の湾曲動作は、スナップアクションあるいはスローアクションのどちらでも差し支えない。さらに、本実施の形態では容器１と支持体１４とは充填剤１５で封着した場合について説明したが、超音波を利用して固着することも可能である。
【００３６】
図３に示すように本発明の第２の実施の形態であるサーマルプロテクタは、図１に示したサーマルプロテクタと同様な構成であるが、異なっているのは、板ばね８の係止部１０が容器１の被係止部１１と接触する箇所において、ＰＢＴ（ポリブチレンテレフタレート）などの樹脂からなる湾曲状の端部を有することである。
【００３７】
この第２の実施の形態によれば、係止部１０と被係止部１１との摺動による耐摩耗性を向上させることができる。
【００３８】
図４に示すように本発明の第３の実施の形態であるサーマルプロテクタは、図１に示したサーマルプロテクタと同様な構成であるが、異なっているのは、容器１の被係止部１１およびその周辺の摺動部に金属体１６を配置したことである。
【００３９】
この第３の実施の形態によれば、係止部１０と被係止部１１との摺動による耐摩耗性を向上させることができる。
【００４０】
図５に示すように本発明の第４の実施の形態であるサーマルプロテクタは、図１に示したサーマルプロテクタと同様な構成であるが、異なっているのは、容器１の形状であり、容器１のリセットボタンが導出した側の容器１の外表面に２個所の凸部１７が形成されていることである。
【００４１】
この第４の実施の形態によれば、凸部１７を利用して、被装着部に別に凹部を設け、両者を嵌合することでサーマルプロテクタを被装着部の任意の箇所に簡単に装着することができる。
【００４２】
なお、図５では凸部の例を示したが、被装着部に凸部を形成すればサーマルプロテクタ側には凹部を形成すればよいことは言うまでもない。また、サーマルプロテクタのリセットボタンを包囲している筒状の容器凸部外面にねじを切れば（図示せず）、ねじ込み式で被装着部に装着することも容易に実現できる。
【００４３】
図６に示すように本発明の第５の実施の形態である電池パックの構成は、となり合う２次電池１８同士にできる空間に本発明の第１ないし第３の実施の形態のいずれかに記載のサーマルプロテクタ１９を電池回路に直列に接続し、かつ電池パックの外部からサーマルプロテクタ１９のリセットボタン２が操作できるように設けられたものである。電池パックのケース２０の一部に貫通孔２１が形成され、この貫通孔２１にリセットボタン２を配置している。
【００４４】
この第５の実施の形態によれば、電池パックに２次短絡等の異常が発生した場合、装着したサーマルプロテクタ１９内の固定電極と可動電極との接点が離間状態となり回路を遮断することができる。異常状態が除かれたことを確認した後、貫通孔２１から突出したリセットボタン２を押し戻して固定電極と可動電極との接点を接触状態にしてやることで再び接点が閉じて給電される。
【００４５】
また、リセットボタン２の先端部は、サーマルプロテクタ１９内の固定電極と可動電極との接点が接触状態では図６のように、電池パックの外表面より常に内側に位置してもよい。
【００４６】
図７に示すように本発明の第６の実施の形態である電池パックは、図６に示した電池パックと同様な構成であるが、図６のものと異なっているのは、サーマルプロテクタ１９のリセットボタン２が導出した側の容器１の外表面の一部に凸部２２が形成され、電池パックのケース２０の側に凹部２３を形成していることである。
【００４７】
この第６の実施の形態によれば、凸部２２と凹部２３とを嵌合することでサーマルプロテクタ１９を電池パックのケース２０に簡単に装着して保持することができるという作用を有する。
【００４８】
図８に示すように本発明の第７の実施の形態である電池パックは、図６に示した電池パックと同様な構成であるが、図６と異なっているのは、貫通孔２１に取付けられ、かつリセットボタン２を操作可能としたゴムなどの弾性をもったキャップ２４を有することである。
【００４９】
この第７の実施の形態によれば、リセットボタン２による手動復帰操作に支障をきたすことなく、作業中に貫通孔２１から侵入し、電池パック内の２次電池およびサーマルプロテクタ１９に悪影響を及ぼす恐れのある水分、ほこり等から電池パックを保護できるという作用を有する。
【００５０】
ただし、キャップ２４は、ケース２０の内部から取付けているが、ケース２０の外表面に取付けても問題ない。
【００５１】
【発明の効果】
以上説明したように、本発明は過電流によって一度動作した後は作業者の手動操作によって復帰する安全性の高いサーマルプロテクタを得ることができ、大電流容量の機器である電動工具等の電池パックに用いることにより、２次電池の２次短絡等の異常が発生した場合に手動で給電を再開できるというすぐれた効果を有する。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態であるサーマルプロテクタにおいて固定電極と可動電極とが接触状態にある断面図
【図２】同じく固定電極と可動電極とが開離状態にある断面図
【図３】本発明の第２の実施の形態であるサーマルプロテクタの要部拡大断面図
【図４】本発明の第３の実施の形態であるサーマルプロテクタの要部拡大断面図
【図５】本発明の第４の実施の形態であるサーマルプロテクタの要部拡大斜視図
【図６】本発明の第５の実施の形態である電池パックの要部断面図
【図７】本発明の第６の実施の形態である電池パックの要部断面図
【図８】本発明の第７の実施の形態である電池パックの要部断面図
【図９】従来のサーマルプロテクタの断面図
【符号の説明】
１容器
２リセットボタン
３樹脂ブロック
４プランジャー
５金属板
６第１のコイルばね
７第２のコイルばね
８板ばね
９熱応動素子
１０係止部
１１被係止部
１２ａ，１２ｂ可動電極
１３ａ，１３ｂ固定電極
１４支持体
１５充填剤
１６金属体
１７凸部
１８電池
１９サーマルプロテクタ
２０電池パックのケース
２１貫通孔
２２凸部
２３凹部
２４キャップ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermal protector for preventing electrical equipment and the like from burning due to overheating and overcurrent, and a secondary battery pack containing the thermal protector.
[0002]
[Prior art]
The self-resetting thermal protector includes a movable electrode having a thermally responsive element that performs a reversal operation by heat, and a fixed electrode that is provided opposite to the movable electrode and that can be contacted with and separated from the movable electrode. In response to an abnormal temperature rise or overcurrent of the device, when the thermal response element exceeds its operating temperature, the thermal response element reverses and opens the contact point between the movable electrode and the fixed electrode, shutting off the power supply and protecting the device To do. Then, when the abnormality of the electrical device is removed and the temperature of the thermal response element decreases, the thermal response element performs the reversing operation again and resumes power feeding. As described above, the self-recovering thermal protector can be used to detect an abnormality of an electric device without replacement, and is used as one of safety elements having a great advantage different from a fuse.
[0003]
As shown in FIG. 9, the conventional thermal protector is connected to a fixed electrode support portion 27 and a thermally responsive element support portion 28 fixed to the resin block 26 and one end portion of the fixed electrode support portion 27 in the container 25. A fixed electrode 29, a thermally responsive element 30 connected to one end of the thermally responsive element support portion 28, and a movable electrode 31 provided at one end of the thermally responsive element 30 are provided. Lead wires 32 are respectively connected to the other end portions of the fixed electrode support portion 27 and the thermally responsive element support portion 28, and each lead wire 32 is led out from the container 25 to the outside. The resin block 26 is fixed in the container 25 with the filler 15.
[0004]
[Problems to be solved by the invention]
Such a conventional self-resetting thermal protector is currently used for devices having a relatively low current capacity such as a mobile phone in the field of secondary battery packs. On the other hand, in the case of equipment with a large current capacity represented by electric tools etc., the self-recovery type is not suitable from the viewpoint of safety. Since the rated current is excessive with respect to the shape and dimension to be formed, there has been no suitable thermal protector for the secondary short circuit so far, and a highly safe thermal protector has been desired.
[0005]
The present invention has been made to solve such problems, and an object of the present invention is to provide a highly safe manual return system thermal protector.
[0006]
[Means for Solving the Problems]
The thermal protector according to claim 1 of the present invention includes a fixed electrode, a movable electrode, and a plunger that contacts and separates the movable electrode with respect to the fixed electrode, in a container having a locked portion on an inner surface thereof. An elastic body arranged in the axial direction of the plunger, an elastic plate supported at the plunger and having a locking portion at one end to be locked to the locked portion of the container; A thermally responsive element that disengages the locking portion of the elastic plate from the locked portion of the container, the fixed electrode includes first and second fixed electrodes spaced apart from each other, and the movable electrode is constant The first and second movable electrodes are fixed to a conductive plate at a distance, and the first and second fixed electrodes and the first and second movable electrodes form a pair, respectively. In the form of double-cut contacts facing each other, A part of the thermal response element is sandwiched between the conductive plate and the elastic plate, and the current path is the first fixed electrode, the first movable electrode, the conductive plate, the second The movable plate and the first fixed electrode are formed. As the locking portion of the elastic plate is detached from the locked portion of the container, the plunger is moved in the axial direction by the extending action of the elastic body. By moving, the contact state between the fixed electrode and the movable electrode is released, the fixed electrode and the movable electrode are separated from each other, the current path is interrupted, and the separated state is maintained. ing.
[0007]
With this configuration, the elastic plate is pushed down by the bending reversal operation of the thermally responsive element accompanying the temperature rise of the device, and the locking portion of the elastic plate is detached from the locked portion of the container. At this time, the plunger is moved by the extension of the elastic body, and the contact state between the fixed electrode and the movable electrode is released and separated, thereby interrupting the circuit.
[0008]
Next, after removing the abnormal state of the device, if the reset button is pushed back to the position where the locking portion and the locked portion of the elastic plate are locked, the contact point between the fixed electrode and the movable electrode is closed again. Power can be supplied.
[0009]
According to a second aspect of the invention, the thermal protector according to claim 1, wherein the elastic body, the first and second coil springs or Rannahli, the first and second fixed electrodes fixed within the support distance is fixed at a, and wherein between the first and second fixed electrode and the first coil spring is embedded in the support body, prior Symbol second coil spring through said electrically conductive plate It has the structure arranged in series facing the first coil spring and supported by one end of the plunger.
[0010]
With this configuration, it is possible to connect and separate the fixed contact and the movable contact by driving the conductive plate in which the movable contact is formed by the expansion and contraction operation of the first coil spring, and the conductive plate is formed by the contraction of the second coil spring. A contact pressure can be generated between the fixed contact and the movable contact by applying a load.
[0011]
The invention according to claim 3 is the thermal protector according to claim 1 or 2, wherein the plunger is fixed to a block having a convex portion, and the convex portion is led out of the container, and the fixed electrode And a reset button for returning the separated state of the movable electrode to the contact state.
[0012]
With this configuration, when the contact between the fixed electrode and the movable electrode is in the separated state, the contact can be returned to the contact state again by pushing back the reset button led out of the container.
[0013]
According to a fourth aspect of the present invention, in the thermal protector according to the third aspect of the present invention, the other end portion of the elastic plate where the engaging portion is not formed is in contact with and supported by a part of the block. is doing.
[0014]
With this configuration, the stability of the elastic plate in a stationary state is increased, and as a result, the contact pressure of the contact point between the fixed electrode and the movable electrode can be stabilized.
[0017]
According to a fifth aspect of the present invention, in the thermal protector according to any one of the first to fourth aspects, the end portion of the locking portion of the elastic plate has a curved shape.
[0018]
With this configuration, wear resistance due to sliding between the locked portion and the locking portion can be improved.
[0019]
Invention according to claim 6, Yes in thermal protector according to any one of claims 1 to 5, a configuration in which the engaged portion of said container and engaging portion of the elastic plate is made of resin or metal is doing.
[0020]
With this configuration, wear resistance due to sliding between the locked portion and the locking portion can be improved.
[0021]
A seventh aspect of the present invention is the thermal protector according to the third aspect , wherein a concave portion or a convex portion is formed on a part of the side from which the reset button is derived.
[0022]
With this configuration, the thermal protector can be easily mounted at an arbitrary position by fitting using the concave portion or the convex portion.
[0023]
The battery pack according to claim 8 , wherein the thermal protector according to claim 3 or 7 is connected in series to a battery circuit in a battery pack in which a plurality of secondary batteries are accommodated, and the fixed electrode of the thermal protector And the movable electrode are in contact with each other and a reset button is installed to turn on the battery circuit.
[0024]
With this configuration, when an abnormality such as a secondary short circuit of the secondary battery occurs, the fixed electrode and the movable electrode are separated from each other, and the battery circuit can be shut off (off state). Thereafter, by pushing back the reset button to bring the fixed electrode and the movable electrode into contact with each other, the battery circuit can be brought into an energized state (on state), and power feeding can be resumed.
[0025]
According to a ninth aspect of the present invention, in the battery pack according to the eighth aspect , an uneven portion is formed on the inner surface of the battery pack, and the uneven portion is fitted with the uneven portion formed in the container of the thermal protector according to the seventh aspect. Thus, the thermal protector is held in the battery pack.
[0026]
With this configuration, the thermal protector can be mounted in the battery pack with a single touch.
[0027]
According to a tenth aspect of the present invention, in the battery pack according to the eighth or ninth aspect , when the fixed electrode and the movable electrode are in contact with each other, the tip of the reset button is on the inner side of the outer surface of the battery pack. It has the structure located in.
[0028]
With this configuration, when the battery pack is mounted on a predetermined device and used, the reset button of the thermal protector can be prevented from hindering the work.
[0029]
The invention according to claim 11, for the battery pack according to any one of claims 8 to 10, wherein attached to the through-hole, and has a structure having a cap which enables operating the reset button Yes.
[0030]
With this configuration, the battery pack can be protected from factors that may adversely affect the secondary battery and the thermal protector inside the battery pack, such as moisture and dust that may enter from the through hole of the battery pack.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, a thermal protector according to a first embodiment of the present invention includes a resin block 3 that also serves as a reset button 2 inside an insulating container 1 made of a resin such as PBT (polybutylene terephthalate). A plate-like plunger 4 made of a metal such as aluminum is provided in the same direction as the central axis of the container 1. A first coil spring 6 and a second coil spring 7 are arranged in series in the same direction as the central axis of the container 1 via a metal plate 5 such as copper at one end of the plunger 4, and the second coil. A metal leaf spring 8 such as copper having elasticity is disposed on the spring side. Here, the leaf spring may be an elastic plate and is not limited to a leaf spring. Further, a conductive thermoresponsive element 9 having one end sandwiched between the metal plate 5 and the leaf spring 8 and the other end pushed down the leaf spring 8 in the direction of arrow A by a reversing operation is provided. In addition, a locking portion 10 formed in a curved shape is provided at one end portion of the leaf spring 8, and one end portion of the locking portion 10 is a locked portion 11 formed at a predetermined position on the inner surface of the container 1. On the other hand, the other end portion where the locking portion is not formed is supported in contact with one end of the resin block 3 extending in an L shape. First and second movable electrodes 12a and 12b made of silver or the like are provided at both ends of the metal plate 5, respectively. In addition, one end portions of the first and second fixed electrodes 13a and 13b whose contact points are made of silver or the like are fixed to an insulating support 14 such as resin, and the other end portions are led out of the container 1. Yes. Then, one end of the first coil spring 6 is embedded in the hole provided in the center of the support 14. The first and second movable electrodes 12a and 12b are in contact with the first and second fixed electrodes 13a and 13b, respectively, and the first and second movable electrodes 12a and 12b are bent by the deflection of the second coil spring 7. And a contact pressure is generated between the contact points of the first and second fixed electrodes 13a and 13b, and the contact points are kept in contact with each other, whereby the current from the outer end of the fixed electrode 13a is sequentially transferred to the movable electrode 12a, A current path that flows through the metal plate 5 and the movable electrode 12b to the external end of the fixed electrode 13b is formed. Here, the current may flow in the direction opposite to the current path. The container 1 is sealed with a support 14 and a filler 15.
[0032]
Next, the operation of the thermal protector will be described.
[0033]
Now, when the temperature of the device (not shown) rises due to overcurrent or excessive temperature rise, the thermally responsive element 9 bends inward so that the leaf spring 8 moves in the direction of the arrow A shown in FIG. When the operating temperature of the thermoresponsive element 9 reaches a predetermined temperature and the pressing amount of the thermoresponsive element 9 exceeds the step width of the locked portion 11, the engagement of the leaf spring 8 is pushed. The stopper 10 is detached from the locked part 11. At this moment, as shown in FIG. 2, the first coil spring 6 and the second coil spring 7 that have been urged in the extension direction extend, and the metal plate 5 and the plunger 4 move in the extension direction. The first and second movable electrodes 12a and 12b attached to the metal plate 5 are separated from the first and second fixed electrodes 13a and 13b, and the contacts are opened to interrupt the current path. As a result, the end of the resin block 3, that is, the reset button 2 projects out of the container 1 by the sum of the extension distances of the first coil spring 6 and the second coil spring 7.
[0034]
Then, after the thermal protector is operated, it is confirmed that the abnormal state of the device has been removed, and if the reset button 2 is pushed back to the position where the locking portion 10 is accommodated in the locked portion 11, the first fixing is performed. The electrode 13a and the first movable electrode 12a, and the second fixed electrode 13b and the second movable electrode 12b are brought into contact with each other, and the contact is closed again so that power can be supplied.
[0035]
In order to efficiently transmit the bending operation of the thermally responsive element 9 to the leaf spring 8, a protrusion may be provided on the leaf spring 8. In addition, the bending operation of the thermally responsive element 9 may be either a snap action or a slow action. Further, in the present embodiment, the case where the container 1 and the support 14 are sealed with the filler 15 has been described. However, the container 1 and the support 14 can be fixed using ultrasonic waves.
[0036]
As shown in FIG. 3, the thermal protector according to the second embodiment of the present invention has the same configuration as that of the thermal protector shown in FIG. Is a curved end portion made of a resin such as PBT (polybutylene terephthalate) at a place where the container 1 comes into contact with the locked portion 11 of the container 1.
[0037]
According to the second embodiment, it is possible to improve the wear resistance due to sliding between the locking portion 10 and the locked portion 11.
[0038]
As shown in FIG. 4, the thermal protector according to the third embodiment of the present invention has the same configuration as the thermal protector shown in FIG. 1, but is different from the locked portion 11 of the container 1. In other words, the metal body 16 is disposed on the sliding portion around it.
[0039]
According to the third embodiment, it is possible to improve the wear resistance due to the sliding between the locking portion 10 and the locked portion 11.
[0040]
As shown in FIG. 5, the thermal protector according to the fourth embodiment of the present invention has the same configuration as the thermal protector shown in FIG. 1, except that the shape of the container 1 is different. That is, two convex portions 17 are formed on the outer surface of the container 1 on the side from which one reset button is derived.
[0041]
According to the fourth embodiment, the convex portion 17 is used to provide a recessed portion in the mounted portion, and the thermal protector can be easily mounted at an arbitrary position of the mounted portion by fitting both of them. be able to.
[0042]
In addition, although the example of the convex part was shown in FIG. 5, if a convex part is formed in a to-be-attached part, it cannot be overemphasized that a concave part should just be formed in the thermal protector side. Further, if a screw is cut on the outer surface of the cylindrical container convex portion surrounding the reset button of the thermal protector (not shown), it can be easily mounted on the mounting portion by a screw-in type.
[0043]
As shown in FIG. 6, the configuration of the battery pack according to the fifth embodiment of the present invention is the same as any one of the first to third embodiments of the present invention in the space that can be formed between the adjacent secondary batteries 18. The described thermal protector 19 is connected in series to the battery circuit, and the reset button 2 of the thermal protector 19 can be operated from the outside of the battery pack. A through hole 21 is formed in a part of the case 20 of the battery pack, and the reset button 2 is disposed in the through hole 21.
[0044]
According to the fifth embodiment, when an abnormality such as a secondary short circuit occurs in the battery pack, the contact point between the fixed electrode and the movable electrode in the mounted thermal protector 19 is in a separated state, and the circuit is interrupted. it can. After confirming that the abnormal state has been removed, the reset button 2 protruding from the through hole 21 is pushed back to bring the contact point between the fixed electrode and the movable electrode into a contact state.
[0045]
Further, the tip of the reset button 2 may always be located inside the outer surface of the battery pack as shown in FIG. 6 when the contact point between the fixed electrode and the movable electrode in the thermal protector 19 is in contact.
[0046]
As shown in FIG. 7, the battery pack according to the sixth embodiment of the present invention has the same configuration as that of the battery pack shown in FIG. 6, but is different from that shown in FIG. The convex portion 22 is formed on a part of the outer surface of the container 1 on the side where the reset button 2 is led out, and the concave portion 23 is formed on the case 20 side of the battery pack.
[0047]
According to the sixth embodiment, the thermal protector 19 can be easily mounted and held on the case 20 of the battery pack by fitting the convex portion 22 and the concave portion 23 together.
[0048]
As shown in FIG. 8, the battery pack according to the seventh embodiment of the present invention has the same configuration as the battery pack shown in FIG. 6, but is different from FIG. And a cap 24 having elasticity such as rubber that enables the reset button 2 to be operated.
[0049]
According to the seventh embodiment, the manual return operation by the reset button 2 is not hindered, and it enters from the through hole 21 during the work, and adversely affects the secondary battery and the thermal protector 19 in the battery pack. The battery pack can be protected from moisture, dust, etc.
[0050]
However, although the cap 24 is attached from the inside of the case 20, there is no problem even if it is attached to the outer surface of the case 20.
[0051]
【The invention's effect】
As described above, the present invention can provide a highly safe thermal protector that is restored by manual operation of an operator after being operated once by an overcurrent, and is a battery pack such as a power tool that is a device with a large current capacity. By using this, it is possible to manually resume power supply when an abnormality such as a secondary short circuit of the secondary battery occurs.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view in which a fixed electrode and a movable electrode are in contact with each other in the thermal protector according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view in which the fixed electrode and the movable electrode are in a separated state. 3 is an enlarged cross-sectional view of a main part of a thermal protector according to a second embodiment of the present invention. FIG. 4 is an enlarged cross-sectional view of an essential part of a thermal protector according to a third embodiment of the present invention. The principal part expansion perspective view of the thermal protector which is the 4th Embodiment of this invention. FIG. 6 is principal part sectional drawing of the battery pack which is the 5th Embodiment of this invention. FIG. 8 is a cross-sectional view of a main part of a battery pack according to a seventh embodiment of the present invention. FIG. 9 is a cross-sectional view of a conventional thermal protector. ]
DESCRIPTION OF SYMBOLS 1 Container 2 Reset button 3 Resin block 4 Plunger 5 Metal plate 6 1st coil spring 7 2nd coil spring 8 Leaf spring 9 Thermally responsive element 10 Locking part 11 Locked part 12a, 12b Movable electrode 13a, 13b Fixed electrode 14 Support 15 Filler 16 Metal body 17 Convex part 18 Battery 19 Thermal protector 20 Battery pack case 21 Through hole 22 Convex part 23 Concave part 24 Cap

Claims

In a container having a locked portion on the inner surface, a fixed electrode, a movable electrode, a plunger for moving the movable electrode toward and away from the fixed electrode, and an elastic body disposed in the axial direction of the plunger, An elastic plate having at one end a locking portion supported by the plunger and locked to the locked portion of the container, and locking the elastic plate from the locked portion of the container by a curve reversal operation And the fixed electrode is composed of first and second fixed electrodes spaced apart from each other, and the movable electrode is fixed to a conductive plate at a certain distance. The first and second fixed electrodes and the first and second movable electrodes are in the form of a double-contact type that is opposed to each other in pairs, A part of the thermally responsive element is composed of the conductive plate and the elastic member. Is sandwiched bets, the current path is the first fixed electrode, the first movable electrode, wherein the conductive plate, the second movable electrode, and is formed by the first fixed electrode, the elastic As the locking portion of the plate disengages from the locked portion of the container, the plunger is moved in the axial direction by the extending action of the elastic body, so that the contact state between the fixed electrode and the movable electrode is changed. The thermal protector characterized in that the fixed electrode and the movable electrode are released and the current path is interrupted to maintain the separated state.

The elastic body, the first and second coil springs or Rannahli, the first and second fixed electrode is fixed at a predetermined distance in the support, and between said first and second fixed electrodes said first coil spring is embedded in the support body, one end portion of the front Stories second coil spring said plunger arranged in series to face the first coil spring through said conductive plate to The thermal protector according to claim 1, wherein the thermal protector is supported by.

The plunger is fixed to a block having a convex portion, and the convex portion is led out of the container and serves as a reset button for returning the separated state between the fixed electrode and the movable electrode to a contact state. The thermal protector according to claim 1 , wherein the thermal protector is provided.

4. The thermal protector according to claim 3, wherein the other end portion of the elastic plate not formed with the latching portion is in contact with and supported by a part of the block.

Thermal protector according to any one of claims 1 to 4, wherein the end portion of the engaging portion of the elastic plate is curved.

Thermal protector according to any one of claims 1 to 5 the engaged portion of said container and engaging portion of the elastic plate is characterized in that it consists of a resin or a metal.

4. The thermal protector according to claim 3 , wherein a concave portion or a convex portion is formed on a part of the outer surface of the container on the side from which the reset button is led out.

A thermal protector according to claim 3 or 7 is connected in series to a battery circuit in a battery pack containing a plurality of secondary batteries, and the reset button of the thermal protector is formed on a part of the battery pack. A battery pack, wherein the battery pack is disposed in the through hole.

A concave portion or a convex portion is formed on the inner surface of the battery pack, and the concave portion or the convex portion is fitted with the concave portion or the convex portion formed in the container of the thermal protector according to claim 7 , and the thermal protector is placed in the battery pack. The battery pack according to claim 8 , wherein the battery pack is held.

Wherein the fixed electrode and the movable electrode in the contact state, the battery pack according to claim 8 or 9 tip of the reset button is characterized in that is located inside the outer surface of the battery pack .

The through hole in the mounted and battery pack according to any one of claims 8 to 10 characterized by having a cap which enables operating the reset button.