TW201833962A - Protection element - Google Patents

Abstract

In order to provide a protection element that can achieve both the improvement of a current rating and the provision of a rapid current shutoff during an abnormality, and also improve insulation reliability after the current shutoff, the present invention is provided with: an insulation substrate (10); first and second electrodes (11, 12) provided on the insulation substrate (10); a heating element (14) formed on the insulation substrate (10); a heating element extracting electrode (16) electrically connected to the heating element (14); a first fusible conductor (31) mounted from the first electrode (11) across to the heating element extracting electrode (16); and a second fusible conductor (32) mounted from the second electrode (12) across to the heating element extracting electrode (16).

Description

保護元件Protective component

本技術係關於一種將電源線或信號線阻斷之保護元件。本申請案係以2016年11月29日於日本提出申請之日本專利申請案編號特願2016-231790、及2017年7月10日於日本提出申請之日本專利申請案編號特願2017-134377為基礎而主張優先權者，該等申請案以參照之方式被引用於本申請案中。This technology relates to a protection element that blocks a power or signal line. Japanese Patent Application No. 2016-231790, filed on November 29, 2016 in Japan, and Japanese Patent Application No. 2017-134377, filed in Japan on July 10, 2017 The applicants claim the priority, and the applications are hereby incorporated by reference.

可充電而重複利用之蓄電池大多係加工為電池組後提供給使用者。尤其是於重量能量密度較高之鋰離子蓄電池中，為了確保使用者及電子設備之安全，通常會將過充電保護、過放電保護等若干保護電路內置於電池組，而具有於特定情形時阻斷電池組之輸出之功能。 於此種保護元件中，存在藉由使用內置於電池組之FET(Field Effect Transistor，場效電晶體)開關進行輸出之打開/關閉(ON/OFF)，而進行電池組之過充電保護或過放電保護動作者。然而，於FET開關因某些原因而發生短路破壞之情形時、施加雷電突波等而流通有瞬時大電流之情形時、或者緣於電池單元之壽命而導致輸出電壓異常降低或相反地輸出過大異常電壓之情形時，亦必須保護電池組或電子設備免於著火等事故。因此，為了於此種所能設想之任何異常狀態下均可安全地阻斷電池單元之輸出，而使用具有藉由來自外部之信號而阻斷電流路徑之功能的保護元件。 作為面向鋰離子蓄電池等之保護電路之阻斷元件，存在如下者，即，如圖13(A)、(B)所示，遍及電流路徑上之第1電極91、發熱體引出電極95、第2電極92間地將可熔導體93連接而形成電流路徑之一部分，使該電流路徑上之可熔導體93藉由過電流所引起之自發熱、或者設置於保護元件內部之發熱體94而熔斷(參照專利文獻1)。於此種保護元件90中，藉由將熔融後之液體狀之可熔導體93集中於與發熱體94相連之發熱體引出電極95、及第1、第2電極91、92上，而將第1、第2電極91、92間分離以阻斷電流路徑。 於保護元件中，可熔導體93會因發熱體94之發熱而熔斷，又，可熔導體93亦會因過電流所引起之自發熱而熔斷，故而將該保護元件由作為外裝零件之蓋構件97密封以免熔斷後之可熔導體93飛散。又，於保護元件90中，為了穩定地實現藉由發熱體94而進行之可熔導體93之熔斷作用，而藉由蓋構件97設置有用以供可熔導體93熔融、流動之內部空間。 再者，於保護元件90中，為了防止可熔導體93之表面氧化，並維持迅速熔斷性，而塗佈有將可熔導體93之表面之氧化被膜去除之助熔劑98。 先前技術文獻 專利文獻 專利文獻1：日本專利第4110967號公報 專利文獻2：日本專利特開2015-97183號公報Most of the rechargeable and reusable batteries are supplied to the user after being processed into a battery pack. Especially in lithium ion batteries with high weight and energy density, in order to ensure the safety of users and electronic devices, some protection circuits such as overcharge protection and overdischarge protection are usually built into the battery pack, and have a resistance in a specific situation. The function of breaking the output of the battery pack. In such a protection element, there is an over-charge protection of the battery pack by using an FET (Field Effect Transistor) switch built in the battery pack to perform ON/OFF of the output. Discharge protection actor. However, when the FET switch is short-circuited due to some reason, when a lightning surge or the like is applied, and an instantaneous large current flows, or the life of the battery cell is abnormal, the output voltage is abnormally lowered or the output is excessively large. In the case of abnormal voltage, it is also necessary to protect the battery pack or electronic equipment from accidents such as fire. Therefore, in order to safely block the output of the battery cell in any abnormal state that can be conceived, a protection element having a function of blocking the current path by a signal from the outside is used. As a blocking element for a protection circuit of a lithium ion battery or the like, as shown in FIGS. 13(A) and (B), the first electrode 91 and the heating element extraction electrode 95 and the first over the current path are present. The fusible conductors 93 are connected between the two electrodes 92 to form a part of the current path, and the fusible conductor 93 on the current path is blown by self-heating caused by overcurrent or by the heat generating body 94 provided inside the protective element. (Refer to Patent Document 1). In the protective element 90, the molten liquid-like soluble conductor 93 is concentrated on the heating element extraction electrode 95 and the first and second electrodes 91 and 92 connected to the heating element 94. 1. The second electrodes 91 and 92 are separated to block the current path. In the protective element, the fusible conductor 93 is blown by the heat generated by the heating element 94, and the fusible conductor 93 is also blown by self-heating due to an overcurrent, so that the protective element is covered by the outer part. The member 97 is sealed to prevent the fusible conductor 93 from scattering after being blown. Further, in the protective element 90, in order to stably achieve the fusing action of the fusible conductor 93 by the heating element 94, the cover member 97 is provided with an internal space for melting and flowing the soluble conductor 93. Further, in the protective element 90, in order to prevent oxidation of the surface of the soluble conductor 93 and maintain rapid fusibility, a flux 98 for removing the oxide film on the surface of the soluble conductor 93 is applied. PRIOR ART DOCUMENT PATENT DOCUMENT Patent Document 1: Japanese Patent No. 4110967 Patent Document 2: Japanese Patent Laid-Open No. 2015-97183

[發明所欲解決之問題] 對於此種表面安裝型保護元件，伴隨所搭載之電子設備或電池組等之高容量化、高額定化，而要求額定電流之提高。 為了使額定電流變大，會採用體積更大之可熔導體以降低電阻值，但另一方面，若採用較大之可熔導體，則存在如下問題，即，由於熔斷部分之容積較大，故而熔斷會花費一些時間，從而於電路等發生異常時無法瞬時阻斷電流。 因此，提出有如下方案，即，於可熔導體設置沿電流方向延伸之槽，增加低熔點金屬體之熔斷開始點，藉此增加體積，增大電流容量，同時使動作時間縮短，使動作時間穩定(參照專利文獻1)。 又，亦提出有如下保護元件，即，使用在焊料等低熔點金屬箔之表面被覆有電阻較低之Ag或Cu等高熔點金屬之保險絲元件，藉此使額定電流變大(參照專利文獻2)。 例如，如圖13、圖14(A)所示，於表面安裝型帶發熱體之保護元件90中，兩端連接於設備之通電路徑上之第1、第2電極91、92、及用以對位於其等中間之發熱體94通電之發熱體引出電極95此等3個電極上配置有可熔導體93。若可熔導體93藉由發熱體94之發熱而熔融，則該可熔導體93會於3個電極91、92、95上鼓起並凝聚，從而發熱體引出電極95與第1、第2電極91、92之間分離而將電流阻斷。然而，若可熔導體93之體積變大，則如圖14(B)所示，熔融導體無法完全收納於發熱體引出電極95之上，第1、第2電極91、92之間短路，從而有損及阻斷後之絕緣可靠性之虞。 又，可熔導體93係遍及第1、第2電極91、92及發熱體引出電極95上而搭載，故而需要將可熔導體93全部熔融之加熱時間，熔斷時間會與體積之大型化成正比地延長，從而發生異常時迅速阻斷通電變得較為困難。 又，於如圖15所示，使用由電阻較低之Ag或Cu等高熔點金屬層93b被覆焊料箔等低熔點金屬層93a之表面的保險絲元件作為可熔導體93之情形時，雖可抑制可熔導體93之體積之增加且使額定電流提高，但實現阻斷所需之時間按使用高熔點金屬之程度相應延長，從而發生異常時迅速阻斷通電變得較為困難。 因此，本技術之目的在於提供一種謀求既能提高額定電流又能於發生異常時迅速阻斷電流的保護元件。 [解決問題之技術手段] 為了解決上述問題，本技術之保護元件具備：絕緣基板；第1、第2電極，其等設置於上述絕緣基板；發熱體，其形成於上述絕緣基板；發熱體引出電極，其與上述發熱體電性連接；第1可熔導體，其係自上述第1電極遍及上述發熱體引出電極而搭載；及第2可熔導體，其係自上述第2電極遍及上述發熱體引出電極而搭載。 [發明之效果] 根據本技術，藉由將第1、第2可熔導體連接於發熱體引出電極上，可削減於電流阻斷時應藉由發熱體之發熱加以熔融之可熔導體之體積，並且可將發熱體之熱高效地傳遞至搭載於應加以熔斷之第1電極與發熱體引出電極之間及第2電極與發熱體引出電極之間的第1、第2可熔導體，從而可迅速地阻斷第1、第2電極間之通電路徑。[Problems to be Solved by the Invention] Such a surface mount type protection element requires an increase in rated current in accordance with the increase in capacity and high rating of an electronic device or a battery pack to be mounted. In order to increase the rated current, a larger volume of the fusible conductor is used to lower the resistance value. On the other hand, if a larger fusible conductor is used, there is a problem that the volume of the fuse portion is large due to the large volume. Therefore, the fuse will take some time, so that the current cannot be instantaneously blocked when an abnormality occurs in the circuit or the like. Therefore, it is proposed to provide a groove extending in the current direction of the fusible conductor to increase the melting start point of the low-melting metal body, thereby increasing the volume, increasing the current capacity, and shortening the operation time, thereby making the operation time Stable (refer to Patent Document 1). In addition, a protective element in which a high-melting-point metal such as Ag or Cu having a low electric resistance is coated on a surface of a low-melting-point metal foil such as solder is used to increase the rated current (see Patent Document 2). ). For example, as shown in FIG. 13 and FIG. 14(A), in the surface-mounted heat-generating element protective element 90, the first and second electrodes 91 and 92 which are connected to the energization path of the device at both ends are used for A fusible conductor 93 is disposed on the three electrodes of the heating element extraction electrode 95 that is energized by the heating element 94 located in the middle. When the fusible conductor 93 is melted by the heat generation of the heating element 94, the fusible conductor 93 bulges and aggregates on the three electrodes 91, 92, 95, so that the heating element extracts the electrode 95 and the first and second electrodes. The separation between 91 and 92 blocks the current. However, when the volume of the soluble conductor 93 is increased, as shown in FIG. 14(B), the molten conductor cannot be completely accommodated on the heating element extraction electrode 95, and the first and second electrodes 91 and 92 are short-circuited. Damage and insulation reliability after blocking. Further, since the fusible conductor 93 is mounted over the first and second electrodes 91 and 92 and the heating element extraction electrode 95, it is necessary to heat the entire meltable conductor 93, and the fusing time is proportional to the increase in volume. It is difficult to quickly block the energization when an abnormality occurs. Further, as shown in FIG. 15, when a fuse element covering the surface of the low-melting-point metal layer 93a such as a solder foil with a high-melting-point metal layer 93b such as Ag or Cu having a low electric resistance is used as the fusible conductor 93, it is possible to suppress The volume of the fusible conductor 93 is increased and the rated current is increased, but the time required to achieve the blocking is lengthened according to the degree of use of the high melting point metal, so that it becomes difficult to quickly block the energization when an abnormality occurs. Accordingly, it is an object of the present technology to provide a protection element that seeks to increase the rated current and quickly block the current in the event of an abnormality. [Means for Solving the Problems] In order to solve the above problems, the protective element of the present technology includes: an insulating substrate; first and second electrodes, which are provided on the insulating substrate; a heat generating body formed on the insulating substrate; and a heat generating body An electrode electrically connected to the heating element; a first fusible conductor mounted from the first electrode over the heating element extraction electrode; and a second fusible conductor extending from the second electrode to the heating element The body is led to the electrode and mounted. [Effects of the Invention] According to the present technology, by connecting the first and second meltable conductors to the heat generating body lead-out electrode, it is possible to reduce the volume of the meltable conductor which should be melted by the heat generated by the heat generating body when the current is blocked. And the heat of the heating element can be efficiently transmitted to the first and second fusible conductors that are mounted between the first electrode to be blown and the heating element extraction electrode, and between the second electrode and the heating element extraction electrode. The energization path between the first and second electrodes can be quickly blocked.

以下，一面參照圖式一面詳細地說明應用本技術之保護元件。再者，本技術並不僅限定於以下實施形態，當然可於不脫離本技術主旨之範圍內進行各種變更。又，圖式係模式性之圖，各尺寸之比例等有時與現實不同。具體尺寸等應參考以下說明進行判斷。又，當然圖式彼此間亦包含尺寸之關係或比例彼此不同之部分。 應用本發明之電路模組3係於電路基板2表面安裝有保護元件1者。電路基板2例如藉由形成鋰離子蓄電池之保護電路等，並表面安裝保護元件1，而於鋰離子蓄電池之充放電路徑上組裝第1、第2可熔導體31、32。而且，若電路模組3中流通超過保護元件1之額定值之大電流，則第1、第2可熔導體31、32藉由自發熱(焦耳熱)而熔斷，藉此阻斷電流路徑。又，電路模組3可藉由如下方式阻斷電流路徑，即，利用設置於電路基板2等之電流控制元件於特定時序向發熱體14通電，而藉由發熱體14之發熱使第1、第2可熔導體31、32熔斷。再者，圖1(A)係將殼體省略而表示應用本發明之保護元件1之俯視圖，圖1(B)係應用本發明之電路模組3之剖視圖。 [保護元件] 如圖1(A)所示，保護元件1具備：絕緣基板10；發熱體14，其積層於絕緣基板10，且由絕緣構件15覆蓋；第1電極11及第2電極12，其等形成於絕緣基板10之兩端；發熱體引出電極16，其以與發熱體14重疊之方式積層於絕緣構件15上；第1可熔導體31，其係自第1電極11遍及發熱體引出電極16而搭載；及第2可熔導體32，其係自第2電極12遍及發熱體引出電極16而搭載。 絕緣基板10係由例如氧化鋁、玻璃陶瓷、富鋁紅柱石、氧化鋯等具有絕緣性之構件呈大致方形狀而形成。絕緣基板10除此以外亦可使用玻璃環氧基板、酚基板等印刷配線基板中所使用之材料，但必須注意可熔導體13熔斷時之溫度。 [第1、第2電極] 如圖2(A)所示，第1、第2電極11、12於絕緣基板10之表面10a上，彼此相隔地配置於相對向之側緣附近，藉此而開放，且藉由於各自與下述發熱體引出電極16之間搭載第1、第2可熔導體31、32而經由第1、第2可熔導體31、32及發熱體引出電極16電性連接。又，如圖2(B)所示，第1、第2電極11、12係藉由如下方式而被阻斷，即，對保護元件1通入超過額定值之大電流，使第1、第2可熔導體31、32藉由自發熱(焦耳熱)而熔斷，或者使發熱體14伴隨通電發熱，而於該第1、第2電極11、12與發熱體引出電極16之間將第1、第2可熔導體31、32熔斷。 如圖3所示，第1、第2電極11、12分別經由設置於絕緣基板10之第1、第2側面10b、10c之城堡型結構與設置於背面10f之外部連接電極11a、12a連接。保護元件1經由該等外部連接電極11a、12a與形成有外部電路之電路基板2連接，而構成該外部電路之通電路徑之一部分。 第1、第2電極11、12可使用Cu或Ag等常用電極材料而形成。又，較佳為，於第1、第2電極11、12之表面上藉由鍍覆處理等公知之手法而塗佈Ni/Au鍍覆、Ni/Pd鍍覆、Ni/Pd/Au鍍覆等被膜。藉此，保護元件1可防止第1、第2電極11、12氧化，且防止額定值伴隨導通電阻之上升而變動。又，可防止回焊安裝保護元件1時因連接第1、第2可熔導體31、32之連接用焊料或形成第1、第2可熔導體31、32外層之低熔點金屬熔融而熔蝕(焊料侵蝕)第1、第2電極11、12。 [發熱體] 發熱體14係具有若通電則發熱之導電性之構件，由例如W、Mo、Ru、Cu、Ag、或以其等為主成分之合金等構成。發熱體14可藉由如下方式而形成，即，將其等之合金、組成物、或化合物之粉狀體與樹脂黏合劑等混合，而製成膏狀物，然後於絕緣基板10上使用網版印刷技術對該膏狀物進行圖案形成、鍛燒等處理。又，於發熱體14中，一端與第1發熱體電極18連接，另一端與第2發熱體電極19連接。 保護元件1以覆蓋發熱體14之方式配設有絕緣構件15，且以隔著該絕緣構件15與發熱體14對向之方式形成有發熱體引出電極16。為了將發熱體14之熱高效地傳遞至第1、第2可熔導體31、32，亦可於發熱體14與絕緣基板10之間亦積層絕緣構件15。作為絕緣構件15，例如可使用玻璃。 發熱體引出電極16之一端連接於第1發熱體電極18，並且經由第1發熱體電極18與發熱體14之一端連續。再者，第1發熱體電極18形成於絕緣基板10之第3側面10d側，第2發熱體電極19形成於絕緣基板10之第4側面10e側。又，第2發熱體電極19經由形成於第4側面10e之城堡型結構與形成於絕緣基板10之背面10f之外部連接電極19a連接。 發熱體14藉由將保護元件1安裝於電路基板2，而經由外部連接電極19a與形成於電路基板2之外部電路連接。而且，發熱體14藉由於將外部電路之通電路徑阻斷之特定時序經由外部連接電極19a而通電、發熱，可將連接第1、第2電極11、12之第1、第2可熔導體31、32熔斷。又，發熱體14自身之通電路徑亦會因第1、第2可熔導體31、32熔斷而被阻斷，故而停止發熱。 [第1、第2可熔導體] 第1可熔導體31係自第1電極11遍及發熱體引出電極16而搭載，第2可熔導體32係自第2電極12遍及發熱體引出電極16而搭載，較佳為該等第1、第2可熔導體31、32於發熱體引出電極16上彼此相隔。 第1可熔導體31例如呈矩形板狀，且連接於發熱體引出電極16之第1電極11側之側緣部及第1電極11。同樣地，第2可熔導體32例如呈矩形板狀，且連接於發熱體引出電極16之第2電極12側之側緣部及第2電極12。藉此，保護元件1構成遍及第1電極11、第1可熔導體31、發熱體引出電極16、第2可熔導體32、第2電極12之通電路徑。 此種保護元件1係將構成第1、第2電極11、12間之通電路徑之可熔導體分割成第1、第2可熔導體31、32並將其等連接於發熱體引出電極16，而將發熱體引出電極16用作第1、第2電極11、12間之通電路徑。藉此，保護元件1相較於將1個可熔導體遍及第1、第2電極間地橫跨發熱體引出電極而搭載之先前之保護元件，發熱體引出電極16上之第1、第2可熔導體31、32間之可熔導體之體積削減。 即，於先前之保護元件中，甚至於連並不直接有助於將第1、第2電極11、12間之通電路徑阻斷的發熱體引出電極16中央之可熔導體都加以熔融，又，藉由使該中央之可熔導體位於發熱體14之正上方而使之先於第1、第2電極11、12間之可熔導體熔融。 另一方面，於保護元件1中，使第1、第2可熔導體31、32於發熱體引出電極16上較佳為相隔地連接，藉此可削減於電流阻斷時應藉由發熱體14之發熱加以熔融之可熔導體之體積，並且可將發熱體之熱高效地傳遞至應加以熔斷之第1電極11與發熱體引出電極16之間及第2電極12與發熱體引出電極16之間的第1、第2可熔導體31、32，從而可迅速地阻斷第1、第2電極11、12間之通電路徑。 又，將發熱體引出電極16用作第1、第2電極11、12間之通電路徑之保護元件1相較於將1個可熔導體遍及第1、第2電極間地橫跨發熱體引出電極而搭載之先前之保護元件，額定電流得以維持。因此，可按對比具備相同額定電流之先前之保護元件而言應加以熔斷之可熔導體之體積所削減之程度，相應迅速地將第1、第2電極11、12間之通電路徑阻斷。 又，保護元件1藉由應加以熔斷之可熔導體之體積之削減，可不使熔融導體自發熱體引出電極16上溢出，而確實地將第1、第2電極11、12間之通電路徑阻斷，並且可提高通電阻斷後之絕緣可靠性(參照圖2(B))。 該等第1、第2可熔導體31、32由利用發熱體14之發熱而迅速熔斷之材料構成，例如可較佳地使用焊料、或以Sn為主成分之無鉛焊料等低熔點金屬。 又，第1、第2可熔導體31、32可使用In、Sn、Pb、Ag、Cu或以其等中之任一者為主成分之合金等金屬而形成。又，第1、第2可熔導體31、32亦可為如圖4所示將內層設為低熔點金屬且將外層設為高熔點金屬之積層體。第1、第2可熔導體31、32例如可藉由焊料箔等構成內層之低熔點金屬層33，且藉由Ag鍍覆層等構成外層之高熔點金屬層34。藉由使第1、第2可熔導體31、32具有將內層設為低熔點金屬層33且將外層設為高熔點金屬層34之積層構造，即便回焊安裝保護元件1時，回焊溫度超過低熔點金屬之熔融溫度，從而低熔點金屬熔融，亦可抑制低熔點金屬向外部流出，從而維持第1、第2可熔導體31、32之形狀。因此，可防止第1、第2可熔導體31、32伴隨變形而出現電阻值局部變高或變低等現象，因此而不於特定溫度熔斷、或未達特定溫度即熔斷等熔斷特性之變動。又，第1、第2可熔導體31、32即便於熔斷時，亦能藉由低熔點金屬熔融而熔蝕(焊料侵蝕)高熔點金屬，藉此以高熔點金屬之熔點以下之溫度將其迅速熔斷。 再者，第1、第2可熔導體31、32係藉由焊料等連接材料39而連接於發熱體引出電極16及第1、第2電極11、12。第1、第2可熔導體31、32可藉由回焊焊接而容易地連接。 第1、第2可熔導體31、32可藉由於低熔點金屬層33使用鍍覆技術成膜高熔點金屬層34而製造。第1、第2可熔導體31、32例如藉由於長條狀之焊料箔之表面實施Ag鍍覆，然後根據所要使用之尺寸將其切斷，可高效地製造，又可容易地使用。 此種第1、第2可熔導體31、32於成為切斷面之兩端面露出有低熔點金屬層33。第1、第2可熔導體31、32可如圖4所示，將該低熔點金屬層33露出之端面朝向第1、第2電極11、12及發熱體引出電極16側而載置，亦可如圖5所示，將由高熔點金屬層34被覆之側面朝向第1、第2電極11、12及發熱體引出電極16側而載置。再者，自阻斷後之絕緣可靠性之觀點而言，與低熔點金屬層33露出之端面面向第1、第2電極11、12與發熱體引出電極16之間之區域的圖5所示之構成相比，低熔點金屬層33露出之端面面向第1、第2電極11、12及發熱體引出電極16側的圖4所示之構成之可靠性較高。 又，第1、第2可熔導體31、32亦可如圖6、圖7所示，藉由於低熔點金屬層33之整面使用鍍覆技術成膜高熔點金屬34而製造。第1、第2可熔導體31、32例如可藉由對按使用尺寸成形之焊料箔之整面實施Ag鍍覆，而於低熔點金屬層33之整面形成高熔點金屬層層34。根據圖6所示之第1、第2可熔導體31、32，低熔點金屬層33未露出於表面，故而於向第1、第2電極11、12及發熱體引出電極16回焊安裝時、或將保護元件1回焊安裝於電路基板時，可完全抑制低熔點金屬層33流出，且可防止因回焊加熱而變形，從而維持熔斷特性。 因此，保護元件1藉由於低熔點金屬層33之整面形成高熔點金屬層34，可不使低熔點金屬層33向第1、第2電極11、12與發熱體引出電極16之間之區域流出，而維持特定之熔斷特性，從而確實地將第1、第2電極11、12間之通電路徑阻斷，並且可提高通電阻斷後之絕緣可靠性(參照圖7)。 又，第1、第2可熔導體31、32、發熱體引出電極16為了防止氧化、提高潤濕性等，較佳為塗佈有助熔劑23。 [殼體] 又，保護元件1為了保護內部，而於絕緣基板10之表面10a上設置有殼體20。殼體20係對應於絕緣基板10之形狀而形成為大致矩形狀。又，如圖1(B)所示，殼體20具有：側面21，其連接於設置有可熔導體13之絕緣基板10之表面10a上；及頂面22，其覆蓋絕緣基板10之表面10a上；且於絕緣基板10之表面10a上，具有充分足夠可熔導體13於熔融時呈球狀膨脹且熔融導體於發熱體引出電極16或第1、第2電極11、12上凝聚之內部空間。 [阻斷試驗] 對應用本技術之保護元件1、及將1個可熔導體遍及第1、第2電極間地橫跨發熱體引出電極16而搭載之先前之保護元件，分別連接截面面積相同之可熔導體，測量自開始向發熱體通電起算之阻斷時間。使用由SnSb合金(Sn：Sb＝95：5，液相點為240℃)構成之低熔點金屬箔，作為可熔導體。其結果，應用本技術之保護元件1相較於先前之保護元件，阻斷時間加快了40%。 又，對保護元件1及先前之保護元件連接具有將內層設為低熔點金屬層且將外層設為高熔點金屬層之積層構造之可熔導體，測量自開始向發熱體通電起算之阻斷時間。使用於保護元件1及先前之保護元件中具有相同截面面積、將由SnSb合金(Sn：Sb＝95：5，液相點為240℃)構成之低熔點金屬箔用作內層、形成Ag鍍覆層作為外層的積層型可熔導體，作為可熔導體。其結果，應用本技術之保護元件1相較於先前之保護元件，阻斷時間加快了20%。 由上述可知，應用本技術之保護元件1可削減於電流阻斷時應藉由發熱體14之發熱加以熔融之可熔導體之體積，且可更迅速地阻斷第1、第2電極11、12間之通電路徑。 [可熔導體片] 又，如圖8所示，保護元件1亦可使複數個(n個)較小之第1、第2可熔導體片31A、32A代替第1、第2可熔導體31、32，遍及第1、第2電極11、12與發熱體引出電極16之間而分別獨立地並聯連接。可熔導體片31A、32A係由與第1、第2可熔導體31、32相同之材料形成，且大小形成為較第1、第2可熔導體31、32小。 於保護元件1中，例如亦可如圖9(A)、(B)所示，使4個可熔導體片31A-1、31A-2、31A-3、31A-4分別空開特定間隔獨立地排列，而作為第1可熔導體31，使4個可熔導體片32A-1、32A-2、32A-3、32A-4排列，而作為第2可熔導體32。 保護元件1藉由使複數個可熔導體片31A、32A排列，可藉由調整可熔導體片31A、32A之數量而容易地調整電流容量。 又，保護元件1藉由使複數個可熔導體片31A、32A排列，可既具備與1個可熔導體相同之電流容量，又防止各可熔導體片31A、32A之變形，從而防止熔斷特性之變動。例如，於上述由成為外層之高熔點金屬層被覆內層之低熔點金屬層的積層型可熔導體中，若平面尺寸變大，則於回焊加熱時等，內層之低熔點金屬層會熔融並流動，因此容易發生變形。藉此，可熔導體會產生厚度局部變厚之部位及變薄之部位，導致電阻值產生不均，從而有無法維持熔斷特性之虞。 因此，保護元件1藉由使複數個可熔導體片31A、32A排列，可使各可熔導體片31A、32A之平面尺寸變小，即便於回焊加熱時等，由熱所引起之變形亦得以防止，從而可維持熔斷特性。 又，於將1個可熔導體遍及第1、第2電極間地橫跨發熱體引出電極而搭載之先前之保護元件中，若為了使電流容量變大而使可熔導體之平面尺寸變大，則可熔導體與發熱體引出電極之接觸面積會變大，故而若高熔點金屬層因低熔點金屬層之加熱、流動而變形，則有將被橫跨之發熱體引出電極破壞(剝離)之虞。然而，於保護元件1中，藉由分割成複數個可熔導體片31A、32A並連接，使變形得以抑制，從而可無破壞發熱體引出電極16之風險地提高熱衝擊之耐性。 再者，作為可熔導體片31A、32A之分割數，自藉由防止回焊加熱時等之變形而確保熔斷特性之可靠性、或緩和對第1、第2電極11、12及發熱體引出電極16之衝擊之方面而言，較理想為使分割數較多，例如，如圖9所示，將可熔導體片31A、32A分別分割成4個或4個以上等。另一方面，若使各可熔導體片31A、32A之分割數較多，則各可熔導體片31A、32A之製造成本及安裝步驟數亦增加。 因此，若考慮到各可熔導體片31A、32A之製造成本、安裝成本等與熔斷特性之可靠性或對第1、第2電極11、12及發熱體引出電極16之衝擊緩和的平衡，則較佳為將可熔導體片31A、32A分別分割成2～3個。 再者，於保護元件1中，如圖9(A)所示，將可熔導體片31A、32A形成為俯視下呈大致矩形狀，並且以沿著通電方向朝向長度方向之方式連接，但亦能以長度方向相對於通電方向呈任意角度之方式傾斜而連接。保護元件1藉由將可熔導體片31A、32A相對於通電方向傾斜地連接，可改變於第1、第2電極11、12及發熱體引出電極16上之設置面積，從而調整元件整體之電流容量。 又，保護元件1亦可如圖10所示，將可熔導體片31A、32A形成為包含低熔點金屬之內層與高熔點金屬之外層之積層體。可熔導體片31A、32A可與上述積層型第1、第2可熔導體31、32相同地，例如，藉由焊料箔等構成內層之低熔點金屬層33，且藉由Ag鍍覆層等構成外層之高熔點金屬層34。藉由使可熔導體片31A、32A具有將內層設為低熔點金屬層33且將外層設為高熔點金屬層34之積層構造，可實現小型化及高額定化，並且即便回焊安裝保護元件1時，回焊溫度超過低熔點金屬之熔融溫度，從而低熔點金屬熔融，亦可維持形狀，可防止熔斷特性之變動。又，可熔導體片31A、32A即便於熔斷時，亦能藉由低熔點金屬熔融而熔蝕(焊料侵蝕)高熔點金屬，藉此以高熔點金屬之熔點以下之溫度將其迅速熔斷。 再者，保護元件1可將各可熔導體片31A、32A全部以相同形狀形成，且由相同數量之可熔導體片31A、32A構成第1可熔導體31及第2可熔導體32，或者亦可使可熔導體片31A與可熔導體片32A之形狀、大小、數量不同。又，保護元件1可使複數個可熔導體片31A之形狀或大小不同，亦可使複數個可熔導體片32A之形狀或大小不同。又，保護元件1可藉由可熔導體片僅形成第1、第2可熔導體31、32中之一者，或者亦可將第1、第2可熔導體31、32與可熔導體片31A、32A併用。保護元件1藉由將各可熔導體片31A、32A之大小或個數適當變更，可使各可熔導體片31A、32A之電阻值針對每個場所而變化，可調整第1、第2可熔導體31、32熔斷之順序、或複數個可熔導體片31A、32A內之各可熔導體片熔斷之順序或速度等。 [電路基板] 繼而，對供安裝保護元件1之電路基板2進行說明。電路基板2例如可使用玻璃環氧基板、玻璃基板、或陶瓷基板等剛性基板、或者軟性基板等公知之絕緣基板。又，電路基板2如圖1(B)所示，具有藉由回焊等表面安裝保護元件1之安裝部，且於安裝部內設置有分別與設置於保護元件1之絕緣基板10之背面10f之外部連接端子11a、12a、19a連接的連接電極。再者，電路基板2安裝有使保護元件1之發熱體14通電之FET等元件。 [電路模組之使用方法] 其次，對保護元件1及將保護元件1表面安裝於電路基板2而成之電路模組3之使用方法進行說明。如圖11所示，電路模組3例如可用作鋰離子蓄電池之電池組內之電路。 例如，保護元件1係組裝至具有電池堆45之電池組40而使用，該電池堆45包含共計4個鋰離子蓄電池之電池單元41～44。 電池組40具備：電池堆45；充放電控制電路50，其控制電池堆45之充放電；應用本發明之保護元件1，其於電池堆45異常時將充電阻斷；檢測電路46，其檢測各電池單元41～44之電壓；及電流控制元件47，其根據檢測電路46之檢測結果控制保護元件1之動作。 電池堆45係將需進行保護控制以免出現過充電及過放電狀態之電池單元41～44串聯連接而成者，經由電池組40之正極端子40a、負極端子40b能夠裝卸地連接於充電裝置55，而被施加來自充電裝置55之充電電壓。將藉由充電裝置55而充電後之電池組40之正極端子40a、負極端子40b連接於要利用電池來動作之電子設備，藉此可使該電子設備動作。 充放電控制電路50具備：2個電流控制元件51、52，其等串聯連接於自電池堆45流向充電裝置55之電流路徑；及控制部53，其控制該等電流控制元件51、52之動作。電流控制元件51、52例如包含電場效應電晶體(以下，稱為FET)，藉由利用控制部53控制閘極電壓，而控制向電池堆45之電流路徑之導通及阻斷。控制部53自充電裝置55接受電力供給而動作，根據由檢測電路46檢測出之檢測結果，以於電池堆45為過放電或過充電時將電流路徑阻斷之方式，控制電流控制元件51、52之動作。 保護元件1例如連接於電池堆45與充放電控制電路50之間之充放電電流路徑上，且其動作由電流控制元件47控制。 檢測電路46與各電池單元41～44連接，檢測各電池單元41～44之電壓值，並將各電壓值供給至充放電控制電路50之控制部53。又，檢測電路46於任一個電池單元41～44變成過充電電壓或過放電電壓時輸出控制電流控制元件47之控制信號。 電流控制元件47例如包含FET，根據自檢測電路46輸出之檢測信號，於電池單元41～44之電壓值變成特定之超過過放電或過充電狀態之電壓時，使保護元件1動作，而以無論電流控制元件51、52之開關動作如何均將電池堆45之充放電電流路徑阻斷之方式進行控制。 於包含如上構成之電池組40中，對保護元件1之構成具體地進行說明。 首先，應用本發明之保護元件1具有如圖12所示之電路構成。即，保護元件1係包含如下構件之電路構成：第1、第2可熔導體31、32，其等經由發熱體引出電極16而串聯連接；及發熱體14，其經由與第1可熔導體31及第2可熔導體32連接之發熱體引出電極16而通電並發熱，藉此將第1、第2可熔導體31、32熔融。又，於保護元件1中，例如，第1、第2可熔導體31、32串聯連接於充放電電流路徑上，發熱體14與電流控制元件47連接。保護元件1之第1電極11經由外部連接電極11a與電池堆45之開放端連接，第2電極12經由外部連接電極12a與電池組40之正極端子40a側之開放端連接。又，發熱體14藉由經由發熱體引出電極16與第1、第2可熔導體31、32連接而與電池組40之充放電電流路徑連接，又，經由第2發熱體電極19及外部連接電極19a與電流控制元件47連接。 若保護元件1之發熱體14通電、發熱，則第1、第2可熔導體31、32熔融，藉由其潤濕性，此種電池組40會被拖引至發熱體引出電極16上(參照圖2(B))。其結果，保護元件1能藉由第1、第2可熔導體31、32熔斷而確實地阻斷電流路徑。又，朝向發熱體14之供電路徑亦會因第1、第2可熔導體31、32熔斷而被阻斷，故而發熱體14之發熱亦停止。 又，電池組40於充放電路徑上流通有超過保護元件1之額定值之預期以外之大電流的情形時，能藉由使第1、第2可熔導體31、32利用自發熱(焦耳熱)熔斷而阻斷電流路徑。 此時，於保護元件1中，使第1、第2可熔導體31、32於發熱體引出電極16較佳為彼此相隔地連接，藉此相較於將1個可熔導體遍及第1、第2電極間地橫跨發熱體引出電極而搭載之先前之保護元件，發熱體引出電極16上之可熔導體之體積削減，故而可削減於電流阻斷時應藉由發熱體14之發熱加以熔融之可熔導體之體積，且可迅速地阻斷第1、第2電極11、12間之通電路徑。 又，保護元件1藉由應加以熔斷之可熔導體之體積之削減，可不使熔融導體自發熱體引出電極16上溢出，而確實地將第1、第2電極11、12間之通電路徑阻斷，且可提高通電阻斷後之絕緣可靠性(參照圖2(B))。 再者，應用本技術之保護元件1並不限定於用在鋰離子蓄電池之電池組中之情形，當然能夠應用於避免IC(integrated circuit，積體電路)之異常過熱等需要利用電氣信號而阻斷電流路徑之各種用途。Hereinafter, the protective element to which the present technology is applied will be described in detail with reference to the drawings. In addition, the present invention is not limited to the embodiments described below, and various modifications can be made without departing from the spirit and scope of the invention. Moreover, the schema is a schematic diagram, and the ratio of each dimension may be different from reality. The specific dimensions and the like should be judged by referring to the following instructions. Moreover, of course, the drawings also include portions in which the relationship or the ratios are different from each other. The circuit module 3 to which the present invention is applied is one in which the protective element 1 is mounted on the surface of the circuit board 2. The circuit board 2 is provided with a protective circuit for a lithium ion battery, for example, and the protective element 1 is surface-mounted, and the first and second meltable conductors 31 and 32 are assembled on the charge and discharge path of the lithium ion battery. Further, when a large current exceeding the rated value of the protective element 1 flows in the circuit module 3, the first and second fusible conductors 31, 32 are blown by self-heating (Joule heat), thereby blocking the current path. . Further, the circuit module 3 can block the current path by energizing the heat generating body 14 at a specific timing by the current control element provided on the circuit board 2 or the like, and the first heat is generated by the heat generating body 14 The second fusible conductors 31, 32 are blown. 1(A) shows a plan view of the protective element 1 to which the present invention is applied, and FIG. 1(B) is a cross-sectional view of the circuit module 3 to which the present invention is applied. [Protection element] As shown in FIG. 1(A), the protection element 1 includes an insulating substrate 10 and a heating element 14 laminated on the insulating substrate 10 and covered with an insulating member 15; the first electrode 11 and the second electrode 12, The heat generating body extraction electrode 16 is laminated on the insulating member 15 so as to overlap the heating element 14 , and the first soluble conductor 31 is applied from the first electrode 11 to the heating element. The lead electrode 16 is mounted and the second fusible conductor 32 is mounted from the second electrode 12 over the heating element lead-out electrode 16 . The insulating substrate 10 is formed of a member having an insulating property such as alumina, glass ceramic, mullite, or zirconia in a substantially square shape. In addition to the insulating substrate 10, a material used for a printed wiring board such as a glass epoxy substrate or a phenol substrate may be used. However, it is necessary to pay attention to the temperature at which the soluble conductor 13 is blown. [First and second electrodes] As shown in Fig. 2(A), the first and second electrodes 11 and 12 are disposed on the front surface 10a of the insulating substrate 10 so as to be spaced apart from each other in the vicinity of the side edges thereof. The first and second fusible conductors 31 and 32 are mounted between the heating element extraction electrodes 16 and the first and second fusible conductors 31 and 32 and the heating element extraction electrode 16 are electrically connected to each other. . Further, as shown in FIG. 2(B), the first and second electrodes 11 and 12 are blocked by, for example, a large current exceeding the rated value is applied to the protective element 1 to make the first The second fusible conductors 31 and 32 are blown by self-heating (Joule heat), or the heating element 14 is heated by electric conduction, and the first and second electrodes 11 and 12 and the heating element extraction electrode 16 are interposed therebetween. 1. The second fusible conductors 31, 32 are blown. As shown in FIG. 3, the first and second electrodes 11 and 12 are connected to the external connection electrodes 11a and 12a provided on the back surface 10f via a castle-type structure provided on the first and second side faces 10b and 10c of the insulating substrate 10. The protective element 1 is connected to the circuit board 2 on which the external circuit is formed via the external connection electrodes 11a and 12a, and constitutes a part of the energization path of the external circuit. The first and second electrodes 11 and 12 can be formed using a common electrode material such as Cu or Ag. Further, it is preferable to apply Ni/Au plating, Ni/Pd plating, Ni/Pd/Au plating to the surfaces of the first and second electrodes 11 and 12 by a known method such as a plating treatment. Wait for the film. Thereby, the protective element 1 can prevent oxidation of the first and second electrodes 11 and 12 and prevent the rated value from fluctuating with an increase in the on-resistance. Further, it is possible to prevent the solder for connection of the first and second fusible conductors 31 and 32 or the low-melting-point metal forming the outer layers of the first and second soluble conductors 31 and 32 from being melted and etched when the protective element 1 is reflow-welded. (Solder erosion) The first and second electrodes 11 and 12. [Heating element] The heating element 14 is a member having electrical conductivity that generates heat when it is energized, and is made of, for example, W, Mo, Ru, Cu, Ag, or an alloy containing the main component thereof. The heating element 14 can be formed by mixing an alloy, a composition, or a powder of a compound with a resin binder or the like to form a paste, and then using a mesh on the insulating substrate 10. The plate printing technique performs processing such as patterning, calcining, and the like on the paste. Further, in the heating element 14, one end is connected to the first heating element electrode 18, and the other end is connected to the second heating element electrode 19. The protective element 1 is provided with an insulating member 15 so as to cover the heating element 14, and the heating element extraction electrode 16 is formed to face the heating element 14 with the insulating member 15 interposed therebetween. In order to efficiently transfer the heat of the heating element 14 to the first and second fusible conductors 31 and 32, the insulating member 15 may be laminated between the heating element 14 and the insulating substrate 10. As the insulating member 15, for example, glass can be used. One end of the heating element extraction electrode 16 is connected to the first heating element electrode 18, and is continuous with one end of the heating element 14 via the first heating element electrode 18. Further, the first heating element electrode 18 is formed on the third side surface 10d side of the insulating substrate 10, and the second heating element electrode 19 is formed on the fourth side surface 10e side of the insulating substrate 10. Further, the second heating element electrode 19 is connected to the external connection electrode 19a formed on the back surface 10f of the insulating substrate 10 via a castle-type structure formed on the fourth side surface 10e. The heating element 14 is connected to an external circuit formed on the circuit board 2 via the external connection electrode 19a by attaching the protection element 1 to the circuit board 2. In addition, the heating element 14 is energized and generates heat via the external connection electrode 19a at a specific timing at which the external path of the external circuit is blocked, and the first and second meltable conductors 31 that connect the first and second electrodes 11 and 12 can be connected. 32 is blown. Further, the energization path of the heating element 14 itself is blocked by the melting of the first and second fusible conductors 31 and 32, so that the heat generation is stopped. [First and second fusible conductors] The first fusible conductor 31 is mounted from the first electrode 11 over the heating element extraction electrode 16 , and the second fusible conductor 32 is extended from the second electrode 12 to the heating element extraction electrode 16 . Preferably, the first and second fusible conductors 31 and 32 are spaced apart from each other on the heat generating body lead-out electrode 16. The first meltable conductor 31 has a rectangular plate shape, for example, and is connected to the side edge portion of the heat generating body lead electrode 16 on the first electrode 11 side and the first electrode 11. Similarly, the second fusible conductor 32 has a rectangular plate shape, for example, and is connected to the side edge portion of the heating element lead-out electrode 16 on the second electrode 12 side and the second electrode 12. Thereby, the protective element 1 constitutes an energizing path for the first electrode 11, the first soluble conductor 31, the heat generating body lead electrode 16, the second meltable conductor 32, and the second electrode 12. In the protective element 1 , the soluble conductor constituting the conduction path between the first and second electrodes 11 and 12 is divided into the first and second soluble conductors 31 and 32 and connected to the heating element extraction electrode 16 . The heating element extraction electrode 16 serves as an energization path between the first and second electrodes 11 and 12. Thereby, the protective element 1 is the first protective element mounted on the heating element lead-out electrode 16 compared to the previous protective element mounted across the heating element lead-out electrode between the first and second electrodes. The volume of the fusible conductor between the fusible conductors 31, 32 is reduced. That is, in the prior protective element, even the fusible conductor that does not directly contribute to the heat-generating body that blocks the energization path between the first and second electrodes 11 and 12 from the center of the electrode 16 is melted, and The meltable conductor between the first and second electrodes 11, 12 is melted by placing the central fusible conductor directly above the heating element 14. On the other hand, in the protective element 1, the first and second fusible conductors 31 and 32 are preferably connected to each other on the heat generating body lead-out electrode 16, thereby reducing the amount of the heat generating body when the current is blocked. The volume of the meltable conductor that is melted by 14 heat, and the heat of the heat generating body can be efficiently transferred between the first electrode 11 and the heat generating body lead electrode 16 to be blown, and the second electrode 12 and the heat generating body lead electrode 16 The first and second fusible conductors 31 and 32 between the two can quickly block the energization path between the first and second electrodes 11 and 12. Further, the protective element 1 in which the heating element lead-out electrode 16 is used as the conduction path between the first and second electrodes 11 and 12 is pulled out across the heating element over the first and second electrodes. The rated current is maintained by the previous protective element mounted on the electrode. Therefore, it is possible to quickly block the energization path between the first and second electrodes 11 and 12 in accordance with the degree of reduction of the volume of the fusible conductor to be blown by the previous protection element having the same rated current. Further, by reducing the volume of the fusible conductor to be fused, the protective element 1 can reliably prevent the molten conductor from overflowing from the heating element lead-out electrode 16 and reliably block the energization path between the first and second electrodes 11 and 12. It is broken, and the insulation reliability after the energization is blocked can be improved (refer to FIG. 2(B)). The first and second fusible conductors 31 and 32 are made of a material that is rapidly blown by heat generation of the heating element 14. For example, solder or a low-melting-point metal such as lead-free solder containing Sn as a main component can be preferably used. Further, the first and second fusible conductors 31 and 32 can be formed using a metal such as In, Sn, Pb, Ag, Cu, or an alloy such as an alloy of any of them. Further, the first and second fusible conductors 31 and 32 may have a laminate in which the inner layer is a low melting point metal and the outer layer is a high melting point metal as shown in FIG. 4 . The first and second fusible conductors 31 and 32 can be formed of, for example, a low-melting-point metal layer 33 of an inner layer by a solder foil or the like, and an outer layer of the high-melting-point metal layer 34 can be formed by an Ag plating layer or the like. By providing the first and second fusible conductors 31 and 32 with a laminated structure in which the inner layer is the low melting point metal layer 33 and the outer layer is the high melting point metal layer 34, the reflow is performed even when the protective element 1 is reflowed. When the temperature exceeds the melting temperature of the low-melting-point metal, the low-melting-point metal is melted, and the low-melting-point metal can be prevented from flowing out to the outside, thereby maintaining the shapes of the first and second fusible conductors 31 and 32. Therefore, it is possible to prevent the first and second fusible conductors 31 and 32 from being locally deformed or lowered due to deformation, and thus the fusing characteristics such as fusing are not blown at a specific temperature or at a specific temperature. . Further, even when the first and second fusible conductors 31 and 32 are melted, they can be melted by the melting of the low-melting-point metal (solder erosion) of the high-melting-point metal, whereby the high-melting-point metal is heated at a temperature lower than the melting point of the high-melting-point metal. Quickly blown. Further, the first and second fusible conductors 31 and 32 are connected to the heating element lead-out electrode 16 and the first and second electrodes 11 and 12 by a connecting material 39 such as solder. The first and second fusible conductors 31, 32 can be easily joined by reflow soldering. The first and second fusible conductors 31, 32 can be manufactured by forming a high-melting-point metal layer 34 by a plating technique using the low-melting-point metal layer 33. The first and second fusible conductors 31 and 32 can be efficiently manufactured and can be easily used, for example, by performing Ag plating on the surface of the elongated solder foil and then cutting it according to the size to be used. The first and second fusible conductors 31 and 32 have exposed low-melting-point metal layers 33 on both end faces of the cut surface. As shown in FIG. 4, the first and second fusible conductors 31 and 32 can be placed on the side faces of the first and second electrodes 11 and 12 and the heat generating body lead-out electrode 16 as shown in FIG. As shown in FIG. 5, the side surface covered with the high-melting-point metal layer 34 is placed toward the first and second electrodes 11 and 12 and the heat generating body lead electrode 16 side. Further, from the viewpoint of insulation reliability after blocking, the end surface exposed to the low-melting-point metal layer 33 faces the region between the first and second electrodes 11 and 12 and the heat generating body lead-out electrode 16 as shown in FIG. The configuration shown in FIG. 4 in which the end faces of the low-melting-point metal layer 33 are exposed to the first and second electrodes 11 and 12 and the heat generating body lead-out electrode 16 is higher in reliability than the configuration. Further, as shown in FIGS. 6 and 7, the first and second fusible conductors 31 and 32 may be manufactured by forming a high-melting-point metal 34 by a plating technique on the entire surface of the low-melting-point metal layer 33. The first and second fusible conductors 31 and 32 can form the high-melting-point metal layer 34 on the entire surface of the low-melting-point metal layer 33 by, for example, performing Ag plating on the entire surface of the solder foil formed by the use size. According to the first and second fusible conductors 31 and 32 shown in FIG. 6, the low-melting-point metal layer 33 is not exposed on the surface, so that the first and second electrodes 11 and 12 and the heating element extraction electrode 16 are reflowed and mounted. When the protective element 1 is reflow-bonded to the circuit board, the flow of the low-melting-point metal layer 33 can be completely suppressed, and deformation due to reflow heating can be prevented, thereby maintaining the fusing characteristics. Therefore, the protective element 1 can form the high-melting-point metal layer 34 by the entire surface of the low-melting-point metal layer 33, so that the low-melting-point metal layer 33 does not flow out to the region between the first and second electrodes 11, 12 and the heat generating body lead-out electrode 16. By maintaining a specific melting characteristic, the energization path between the first and second electrodes 11 and 12 is surely blocked, and the insulation reliability after the energization is blocked can be improved (see FIG. 7). Further, the first and second meltable conductors 31 and 32 and the heat generating body lead-out electrode 16 are preferably coated with the flux 23 in order to prevent oxidation and improve wettability. [Shell] Further, the protective element 1 is provided with a casing 20 on the surface 10a of the insulating substrate 10 in order to protect the inside. The casing 20 is formed in a substantially rectangular shape in accordance with the shape of the insulating substrate 10. Further, as shown in FIG. 1(B), the casing 20 has a side surface 21 which is connected to the surface 10a of the insulating substrate 10 on which the fusible conductor 13 is provided, and a top surface 22 which covers the surface 10a of the insulating substrate 10. On the surface 10a of the insulating substrate 10, there is sufficient space for the soluble conductor 13 to expand in a spherical shape upon melting, and the molten conductor is condensed on the heating element extraction electrode 16 or the first and second electrodes 11, 12 . [Blocking test] The protective element 1 to which the present technique is applied, and the previous protective element in which one of the fusible conductors is placed across the heating element lead-out electrode 16 between the first and second electrodes, respectively, has the same cross-sectional area The fusible conductor measures the blocking time from the start of energization to the heating element. A low melting point metal foil composed of a SnSb alloy (Sn: Sb = 95:5, a liquidus point of 240 ° C) was used as a fusible conductor. As a result, the protection element 1 to which the present technique is applied is 40% faster than the previous protection element. Further, a protective conductor having a laminated structure in which the inner layer is a low melting point metal layer and the outer layer is a high melting point metal layer is connected to the protective element 1 and the previous protective element, and the measurement is stopped from the start of energization to the heating element. time. A low melting point metal foil composed of a SnSb alloy (Sn: Sb = 95:5, a liquidus point of 240 ° C) is used as an inner layer for forming Ag plating in the protective element 1 and the previous protective element having the same cross-sectional area. The layer acts as a layered fusible conductor of the outer layer as a fusible conductor. As a result, the protection element 1 to which the present technique is applied has an increase in blocking time by 20% compared to the previous protection element. As described above, the protective element 1 to which the present technology is applied can reduce the volume of the fusible conductor which should be melted by the heat generated by the heating element 14 when the current is blocked, and can block the first and second electrodes 11 more quickly. 12 power-on paths. [Fusible Conductor Sheet] Further, as shown in FIG. 8, the protective element 1 may replace a plurality of (n) smaller first and second fusible conductor pieces 31A, 32A in place of the first and second fusible conductors. 31 and 32 are connected in parallel independently of each other between the first and second electrodes 11 and 12 and the heating element extraction electrode 16. The fusible conductor pieces 31A and 32A are formed of the same material as the first and second fusible conductors 31 and 32, and are formed to be smaller in size than the first and second fusible conductors 31 and 32. In the protective element 1, for example, as shown in FIGS. 9(A) and (B), the four fusible conductor pieces 31A-1, 31A-2, 31A-3, and 31A-4 are separated by a specific interval. As the first fusible conductor 31, the four fusible conductor pieces 32A-1, 32A-2, 32A-3, and 32A-4 are arranged to be the second fusible conductor 32. The protective element 1 can easily adjust the current capacity by arranging the plurality of fusible conductor pieces 31A, 32A by adjusting the number of the fusible conductor pieces 31A, 32A. Further, by arranging the plurality of fusible conductor pieces 31A and 32A, the protective element 1 can have the same current capacity as that of one of the fusible conductors, and can prevent deformation of the respective fusible conductor pieces 31A and 32A, thereby preventing the fusing characteristics. Changes. For example, in the laminated type fusible conductor in which the low-melting-point metal layer of the inner layer is coated with the high-melting-point metal layer as the outer layer, if the planar size is increased, the low-melting-point metal layer of the inner layer is heated during reflow heating or the like. It melts and flows, so it is prone to deformation. As a result, the meltable conductor has a portion where the thickness is locally thickened and a portion where the thickness is thinned, resulting in unevenness in the resistance value, and there is a possibility that the fuse property cannot be maintained. Therefore, by arranging the plurality of fusible conductor pieces 31A and 32A, the protective element 1 can reduce the planar size of each of the fusible conductor pieces 31A and 32A, and even if it is heated during reflow soldering or the like, the deformation caused by heat is also caused. It is prevented so that the fusing characteristics can be maintained. In the prior protective element in which one of the fusible conductors is mounted across the heating element extraction electrode between the first and second electrodes, the planar size of the fusible conductor is increased in order to increase the current capacity. The contact area between the fusible conductor and the heating element lead-out electrode is increased. Therefore, if the high-melting-point metal layer is deformed by heating or flowing of the low-melting-point metal layer, the electrode of the heating element that is traversed is broken (peeled). After that. However, in the protective element 1, by dividing into a plurality of fusible conductor pieces 31A, 32A and connecting them, the deformation is suppressed, and the thermal shock resistance can be improved without damaging the heat generating body to extract the electrode 16. In addition, as the number of divisions of the fusible conductor pieces 31A and 32A, the reliability of the fusing characteristics is ensured or the first and second electrodes 11 and 12 and the heating element are extracted from the deformation by heating during reflow soldering or the like. In terms of the impact of the electrode 16, it is preferable to divide the number of divisions. For example, as shown in Fig. 9, the fusible conductor pieces 31A and 32A are divided into four or four or more. On the other hand, if the number of divisions of each of the fusible conductor pieces 31A and 32A is large, the manufacturing cost and the number of mounting steps of the respective fusible conductor pieces 31A and 32A also increase. Therefore, considering the balance between the manufacturing cost and the mounting cost of each of the fusible conductor pieces 31A and 32A and the reliability of the fusing characteristics or the impact relaxation of the first and second electrodes 11 and 12 and the heating element extraction electrode 16, Preferably, the fusible conductor pieces 31A and 32A are divided into two to three, respectively. Further, in the protective element 1, as shown in FIG. 9(A), the fusible conductor pieces 31A and 32A are formed in a substantially rectangular shape in plan view, and are connected in the longitudinal direction along the energizing direction, but It can be connected so as to be inclined at an arbitrary angle with respect to the energization direction in the longitudinal direction. The protective element 1 is connected to the first and second electrodes 11 and 12 and the heat generating body lead-out electrode 16 by changing the area of the first and second electrodes 11 and 12 and the heat generating body lead-out electrode 16 by obliquely connecting the conductive conductor pieces 31A and 32A with respect to the energizing direction, thereby adjusting the current capacity of the entire element. . Further, as shown in FIG. 10, the protective element 1 may form the fusible conductor pieces 31A and 32A as a laminate including an inner layer of a low melting point metal and an outer layer of a high melting point metal. The fusible conductor pieces 31A and 32A may be formed of a low-melting-point metal layer 33 of an inner layer by a solder foil or the like in the same manner as the above-described laminated first and second fusible conductors 31 and 32, and may be coated with Ag. And a high melting point metal layer 34 constituting the outer layer. By making the fusible conductor pieces 31A and 32A have a laminated structure in which the inner layer is the low melting point metal layer 33 and the outer layer is the high melting point metal layer 34, miniaturization and high rating can be achieved, and even if reflow soldering is installed In the case of the element 1, the reflow temperature exceeds the melting temperature of the low-melting-point metal, so that the low-melting-point metal is melted, and the shape can be maintained, and the fluctuating property can be prevented from fluctuating. Further, even when the fusible conductor pieces 31A and 32A are melted, they can be melted by the melting of the low-melting-point metal (solder erosion) of the high-melting-point metal, whereby the high-melting-point metal is rapidly melted at a temperature lower than the melting point of the high-melting-point metal. Further, the protective element 1 may be formed of all of the fusible conductor pieces 31A, 32A in the same shape, and the first number of the fusible conductor pieces 31A, 32A constitute the first fusible conductor 31 and the second fusible conductor 32, or The shape, size, and number of the fusible conductor piece 31A and the fusible conductor piece 32A may be different. Further, the protective element 1 may have a different shape or size of the plurality of fusible conductor pieces 31A, and may have different shapes or sizes of the plurality of fusible conductor pieces 32A. Further, the protective element 1 may form only one of the first and second fusible conductors 31, 32 by the fusible conductor piece, or may also be the first and second fusible conductors 31, 32 and the fusible conductor piece. 31A, 32A are used together. By appropriately changing the size or the number of the respective fusible conductor pieces 31A and 32A, the protective element 1 can change the resistance values of the respective fusible conductor pieces 31A and 32A for each place, and can adjust the first and second colors. The order in which the fuse conductors 31, 32 are blown, or the order or speed at which the respective fusible conductor pieces in the plurality of fusible conductor pieces 31A, 32A are blown. [Circuit Substrate] Next, the circuit board 2 on which the protective element 1 is mounted will be described. As the circuit board 2, for example, a rigid substrate such as a glass epoxy substrate, a glass substrate or a ceramic substrate, or a known insulating substrate such as a flexible substrate can be used. Further, as shown in FIG. 1(B), the circuit board 2 has a mounting portion on which the protective element 1 is surface-mounted by reflow soldering or the like, and is provided in the mounting portion with the back surface 10f of the insulating substrate 10 provided on the protective element 1, respectively. A connection electrode to which the external connection terminals 11a, 12a, and 19a are connected. Further, an element such as an FET that energizes the heating element 14 of the protective element 1 is attached to the circuit board 2. [Method of Using Circuit Module] Next, a method of using the protective element 1 and the circuit module 3 in which the surface of the protective element 1 is mounted on the circuit board 2 will be described. As shown in FIG. 11, the circuit module 3 can be used, for example, as a circuit in a battery pack of a lithium ion battery. For example, the protective element 1 is used by being assembled to a battery pack 40 having a battery stack 45 containing battery cells 41 to 44 of a total of four lithium ion batteries. The battery pack 40 includes a battery stack 45, a charge and discharge control circuit 50 that controls charging and discharging of the battery stack 45, and a protective element 1 of the present invention that blocks charging when the battery stack 45 is abnormal; the detecting circuit 46 detects The voltage of each of the battery cells 41 to 44; and the current control component 47 controls the operation of the protection component 1 based on the detection result of the detection circuit 46. The battery stack 45 is configured such that the battery cells 41 to 44 in the overcharged and overdischarged state are connected in series, and are detachably connected to the charging device 55 via the positive terminal 40a and the negative terminal 40b of the battery pack 40. The charging voltage from the charging device 55 is applied. The positive electrode terminal 40a and the negative electrode terminal 40b of the battery pack 40, which is charged by the charging device 55, are connected to an electronic device to be operated by the battery, whereby the electronic device can be operated. The charge and discharge control circuit 50 includes two current control elements 51 and 52 connected in series to a current path flowing from the battery stack 45 to the charging device 55, and a control unit 53 that controls the operations of the current control elements 51 and 52. . The current control elements 51 and 52 include, for example, an electric field effect transistor (hereinafter referred to as an FET), and the gate voltage is controlled by the control unit 53, thereby controlling the conduction and blocking of the current path to the battery stack 45. The control unit 53 operates by receiving power supply from the charging device 55, and controls the current control element 51 such that the current path is blocked when the battery stack 45 is overdischarged or overcharged based on the detection result detected by the detection circuit 46. 52 action. The protection element 1 is connected, for example, to a charge and discharge current path between the battery stack 45 and the charge and discharge control circuit 50, and its operation is controlled by the current control element 47. The detection circuit 46 is connected to each of the battery cells 41 to 44, detects the voltage values of the battery cells 41 to 44, and supplies the respective voltage values to the control unit 53 of the charge and discharge control circuit 50. Further, the detection circuit 46 outputs a control signal for controlling the current control element 47 when any one of the battery cells 41 to 44 becomes an overcharge voltage or an overdischarge voltage. The current control element 47 includes, for example, an FET, and operates the protection element 1 when the voltage values of the battery cells 41 to 44 become a voltage exceeding a state of overdischarge or overcharge according to a detection signal output from the detection circuit 46. How the switching operations of the current control elements 51, 52 both control the manner in which the charge and discharge current paths of the battery stack 45 are blocked. In the battery pack 40 including the above configuration, the configuration of the protective element 1 will be specifically described. First, the protective element 1 to which the present invention is applied has a circuit configuration as shown in FIG. In other words, the protective element 1 includes a circuit configuration of the first and second fusible conductors 31 and 32 connected in series via the heating element extraction electrode 16 and the heating element 14 via the first soluble conductor 31 and the heat generating body connected to the second meltable conductor 32 take out the electrode 16 and conduct electricity and generate heat, thereby melting the first and second meltable conductors 31 and 32. Further, in the protective element 1, for example, the first and second fusible conductors 31, 32 are connected in series to the charge and discharge current path, and the heating element 14 is connected to the current control element 47. The first electrode 11 of the protective element 1 is connected to the open end of the battery stack 45 via the external connection electrode 11a, and the second electrode 12 is connected to the open end of the battery pack 40 on the positive electrode terminal 40a side via the external connection electrode 12a. Further, the heating element 14 is connected to the first and second meltable conductors 31 and 32 via the heating element extraction electrode 16, and is connected to the charge and discharge current path of the battery unit 40, and is connected to the external heat generating body electrode 19 and the external portion. The electrode 19a is connected to the current control element 47. When the heating element 14 of the protective element 1 is energized and generates heat, the first and second fusible conductors 31 and 32 are melted, and by virtue of the wettability, the battery pack 40 is towed to the heating element extraction electrode 16 ( Refer to Figure 2 (B)). As a result, the protective element 1 can be surely blocked by the current path by the first and second fusible conductors 31 and 32 being blown. Further, the power supply path to the heating element 14 is also blocked by the melting of the first and second fusible conductors 31 and 32, so that the heat generation of the heating element 14 is also stopped. Further, when the battery pack 40 has a large current exceeding the expected value of the protection element 1 in the charge/discharge path, the first and second fusible conductors 31 and 32 can be self-heated (Joule). Thermal) blows to block the current path. At this time, in the protective element 1, the first and second meltable conductors 31 and 32 are preferably connected to each other at the heat generating body lead-out electrode 16, thereby making the first and second fusible conductors pass through the first one. The former protective element is mounted between the second electrodes across the heating element extraction electrode, and the volume of the fusible conductor on the heating element extraction electrode 16 is reduced, so that it can be reduced by the heat generated by the heating element 14 when the current is blocked. The volume of the meltable conductor is melted, and the energization path between the first and second electrodes 11 and 12 can be quickly blocked. Further, by reducing the volume of the fusible conductor to be fused, the protective element 1 can reliably prevent the molten conductor from overflowing from the heating element lead-out electrode 16 and reliably block the energization path between the first and second electrodes 11 and 12. It is broken, and the insulation reliability after the energization is blocked can be improved (refer to FIG. 2(B)). Furthermore, the protection element 1 to which the present technology is applied is not limited to the case of being used in a battery pack of a lithium ion battery, and can of course be applied to avoid abnormal overheating of an integrated circuit (IC), etc., which is required to be blocked by an electrical signal. Various uses of the breaking current path.

1‧‧‧保護元件1‧‧‧Protection components

2‧‧‧電路基板2‧‧‧ circuit board

3‧‧‧電路模組3‧‧‧Circuit Module

10‧‧‧絕緣基板10‧‧‧Insert substrate

10a‧‧‧表面10a‧‧‧ surface

10b‧‧‧第1側面10b‧‧‧1st side

10c‧‧‧第2側面10c‧‧‧2nd side

10d‧‧‧第3側面10d‧‧‧3rd side

10e‧‧‧第4側面10e‧‧‧4th side

10f‧‧‧背面10f‧‧‧back

11‧‧‧第1電極11‧‧‧1st electrode

11a‧‧‧外部連接電極11a‧‧‧External connection electrode

12‧‧‧第2電極12‧‧‧2nd electrode

12a‧‧‧外部連接電極12a‧‧‧External connection electrode

14‧‧‧發熱體14‧‧‧heating body

15‧‧‧絕緣構件15‧‧‧Insulating components

16‧‧‧發熱體引出電極16‧‧‧heating body extraction electrode

18‧‧‧第1發熱體電極18‧‧‧1st heating element electrode

19‧‧‧第2發熱體電極19‧‧‧2nd heating element electrode

19a‧‧‧外部連接電極19a‧‧‧External connection electrode

20‧‧‧殼體20‧‧‧shell

21‧‧‧側面21‧‧‧ side

21a‧‧‧角部21a‧‧‧ corner

22‧‧‧頂面22‧‧‧ top surface

23‧‧‧熔劑23‧‧‧flux

31‧‧‧第1可熔導體31‧‧‧1st fusible conductor

31A‧‧‧第1可熔導體片31A‧‧‧1st fusible conductor piece

31A-1、31A-2、31A-3、31A-4‧‧‧可熔導體片31A-1, 31A-2, 31A-3, 31A-4‧‧‧ fusible conductor pieces

32‧‧‧第2可熔導體32‧‧‧2nd fusible conductor

32A‧‧‧第2可熔導體片32A‧‧‧2nd fusible conductor piece

32A-1、32A-2、32A-3、32A-4‧‧‧可熔導體片32A-1, 32A-2, 32A-3, 32A-4‧‧‧ fusible conductor pieces

33‧‧‧低熔點金屬層33‧‧‧Low-melting metal layer

34‧‧‧高熔點金屬層34‧‧‧High melting point metal layer

39‧‧‧連接材料39‧‧‧Connecting materials

40‧‧‧電池組40‧‧‧Battery Pack

40a‧‧‧正極端子40a‧‧‧positive terminal

40b‧‧‧負極端子40b‧‧‧Negative terminal

41～44‧‧‧電池單元41～44‧‧‧ battery unit

45‧‧‧電池堆45‧‧‧Battery stack

46‧‧‧檢測電路46‧‧‧Detection circuit

47‧‧‧電流控制元件47‧‧‧ Current control components

50‧‧‧充放電控制電路50‧‧‧Charge and discharge control circuit

51、52‧‧‧電流控制元件51, 52‧‧‧ Current control components

53‧‧‧控制部53‧‧‧Control Department

55‧‧‧充電裝置55‧‧‧Charging device

90‧‧‧保護元件90‧‧‧Protection components

91‧‧‧第1電極91‧‧‧1st electrode

92‧‧‧第2電極92‧‧‧2nd electrode

93‧‧‧可熔導體93‧‧‧Solid conductor

93a‧‧‧低熔點金屬層93a‧‧‧low melting point metal layer

93b‧‧‧高熔點金屬層93b‧‧‧high melting point metal layer

94‧‧‧發熱體94‧‧‧heating body

95‧‧‧發熱體引出電極95‧‧‧heating body extraction electrode

97‧‧‧蓋構件97‧‧‧Cover components

98‧‧‧助熔劑98‧‧‧ Flux

圖1(A)係將殼體省略而表示應用本技術之保護元件之外觀立體圖，圖1(B)係表示應用本技術之電路模組之剖視圖。 圖2(A)係表示應用本技術之保護元件的可熔導體熔斷前之狀態之俯視圖，圖2(B)係表示可熔導體熔斷後之狀態之俯視圖。 圖3係表示應用本技術之保護元件之外觀立體圖。 圖4係將殼體省略而表示使用有具備構成內層之低熔點金屬層及構成外層之高熔點金屬層之積層型可熔導體的保護元件之外觀立體圖。 圖5係將殼體省略而表示將由高熔點金屬層被覆低熔點金屬層之側面朝向第1、第2電極及發熱體引出電極側而搭載有第1、第2可熔導體的保護元件之外觀立體圖。 圖6係將殼體省略而表示搭載有由高熔點金屬層被覆低熔點金屬層之整面之第1、第2可熔導體的保護元件之外觀立體圖。 圖7(A)係表示圖6所示之保護元件之可熔導體熔斷前之狀態之俯視圖，圖7(B)係表示可熔導體熔斷後之狀態之俯視圖。 圖8係將殼體省略而表示排列有複數個可熔導體片之保護元件之俯視圖。 圖9(A)係表示使用有可熔導體片之保護元件熔斷前之狀態之俯視圖，圖9(B)係表示可熔導體片熔斷後之狀態之俯視圖。 圖10係將殼體省略而表示使用有具備構成內層之低熔點金屬層及構成外層之高熔點金屬層之積層型可熔導體片的保護元件之外觀立體圖。 圖11係表示使用有應用本發明之保護元件之電池電路之一構成例的電路圖。 圖12係應用本發明之保護元件之電路圖。 圖13係將殼體省略而表示將1個可熔導體遍及第1、第2電極間地橫跨發熱體引出電極而搭載之先前之保護元件之圖，圖13(A)係外觀立體圖，圖13(B)係剖視圖。 圖14(A)係表示先前之保護元件之可熔導體熔斷前之狀態之俯視圖，圖14(B)係表示可熔導體熔斷後之狀態之俯視圖。 圖15係將殼體省略而表示使用有具備構成內層之低熔點金屬層及構成外層之高熔點金屬層之積層型可熔導體的先前之保護元件之外觀立體圖。1(A) is a perspective view showing the appearance of a protective element to which the present technology is applied, and FIG. 1(B) is a cross-sectional view showing a circuit module to which the present technology is applied. Fig. 2(A) is a plan view showing a state before the fusible conductor to which the protective element of the present technology is applied, and Fig. 2(B) is a plan view showing a state after the fusible conductor is blown. Fig. 3 is a perspective view showing the appearance of a protective member to which the present technology is applied. Fig. 4 is a perspective view showing the appearance of a protective element using a laminated type fusible conductor having a low melting point metal layer constituting an inner layer and a high melting point metal layer constituting an outer layer, which is omitted from the casing. 5 is a view showing the appearance of a protective element in which the first and second fusible conductors are mounted on the side faces of the first and second electrodes and the heat generating body lead-out electrode by the side surface of the low-melting-point metal layer covered with the high-melting-point metal layer. Stereo picture. Fig. 6 is an external perspective view showing a protective element in which the first and second meltable conductors on which the entire surface of the low-melting-point metal layer is coated with the high-melting-point metal layer is omitted. Fig. 7(A) is a plan view showing a state before the fusible conductor of the protective element shown in Fig. 6 is blown, and Fig. 7(B) is a plan view showing a state after the fusible conductor is blown. Fig. 8 is a plan view showing the protective element in which a plurality of fusible conductor pieces are arranged, with the housing omitted. Fig. 9(A) is a plan view showing a state before the protective element using the fusible conductor piece is blown, and Fig. 9(B) is a plan view showing a state after the fusible conductor piece is blown. Fig. 10 is an external perspective view showing a protective element using a laminated type fusible conductor sheet having a low melting point metal layer constituting an inner layer and a high melting point metal layer constituting an outer layer, which is omitted from the casing. Fig. 11 is a circuit diagram showing an example of a configuration of a battery circuit using a protective element to which the present invention is applied. Figure 12 is a circuit diagram of a protective element to which the present invention is applied. FIG. 13 is a view showing a conventional protective element in which one of the fusible conductors is placed across the heating element lead-out electrode between the first and second electrodes, and FIG. 13(A) is an external perspective view. 13 (B) is a cross-sectional view. Fig. 14(A) is a plan view showing a state before the fusible conductor of the prior protective element is blown, and Fig. 14(B) is a plan view showing a state after the fusible conductor is blown. Fig. 15 is a perspective view showing the appearance of a conventional protective element using a laminated type fusible conductor having a low melting point metal layer constituting an inner layer and a high melting point metal layer constituting an outer layer, which is omitted from the casing.

Claims (5)

一種保護元件，其具備： 絕緣基板； 第1、第2電極，其等設置於上述絕緣基板； 發熱體，其形成於上述絕緣基板； 發熱體引出電極，其與上述發熱體電性連接； 第1可熔導體，其係自上述第1電極遍及上述發熱體引出電極而搭載；及 第2可熔導體，其係自上述第2電極遍及上述發熱體引出電極而搭載。A protective element comprising: an insulating substrate; first and second electrodes disposed on the insulating substrate; a heating element formed on the insulating substrate; and a heating element extraction electrode electrically connected to the heating element; A soluble conductor that is mounted from the first electrode over the heating element extraction electrode, and a second meltable conductor that is mounted from the second electrode over the heating element extraction electrode. 如請求項1之保護元件，其中上述第1、第2可熔導體於上述發熱體引出電極上彼此相隔。A protective element according to claim 1, wherein said first and second meltable conductors are spaced apart from each other on said heat generating body lead-out electrode. 如請求項1或2之保護元件，其中使複數個第1、第2可熔導體片代替上述第1、第2可熔導體或與上述第1、第2可熔導體一併分別獨立地排列於上述第1、第2電極與上述發熱體引出電極之間。The protective element according to claim 1 or 2, wherein the plurality of first and second fusible conductor pieces are arranged separately from the first and second fusible conductors or separately from the first and second fusible conductors The first electrode and the second electrode are connected to the heating element extraction electrode. 如請求項1或2之保護元件，其中上述第1、第2可熔導體或上述第1、第2可熔導體片分別具有將內層設為低熔點金屬層且將外層設為高熔點金屬層之積層構造。The protective element according to claim 1 or 2, wherein the first or second fusible conductor or the first and second fusible conductor sheets respectively have an inner layer as a low melting point metal layer and an outer layer as a high melting point metal The layered structure of the layer. 如請求項1或2之保護元件，其中上述發熱體與上述發熱體引出電極重疊。A protective element according to claim 1 or 2, wherein said heat generating body overlaps said heat generating body lead-out electrode.