WO2015020111A1 - Protective element and battery pack - Google Patents

Abstract

Provided are a protective element and a battery pack that maintain current capacity at the time of overcurrent protection and that use heat emitted by a heating element to reliably cause melting. The protective element is provided with: a first insulating substrate (55); first and second external electrodes (51, 52); a heating element (57) that is provided to the rear surface (55b) side of the first insulating substrate (55); front/rear surface electrodes (56, 64) that are provided between the first external electrode (51) and the second external electrode (52) of the surface (55a) of the first insulating substrate (55); a meltable conductor (53) that is layered across the first and second external electrodes (51, 52) so as to overlap with the surface electrode (56) on the front surface (55a); a through hole (58) comprising a conductive layer (65) on the inner surface thereof; and a preliminary solder (66) that is used to fill the interior of the through hole (58). The heat of the heating element (57) causes the preliminary solder (66) and the meltable conductor (53) to melt. The wettability of the front/rear surface electrodes (56, 64), the conductor layer (65) that is within the through hole (58), and the like causes the melted preliminary solder (66) and the meltable conductor (53) to move to the rear surface (55b) side of the high-temperature first insulating substrate (55).

Description

Protective element and battery pack

The present invention relates to a protection element and a battery pack for protecting a circuit connected on a current path by fusing the current path. This application is based on Japanese Patent Application No. 2013-163950 filed on August 7, 2013 in Japan and Japanese Patent Application No. 2014-113044 filed on May 30, 2014. Priority is claimed and these applications are incorporated herein by reference.

Most of the rechargeable batteries that can be charged and used repeatedly are processed into battery packs and provided to users. Particularly in lithium ion secondary batteries with high weight energy density, in order to ensure the safety of users and electronic devices, in general, a battery pack incorporates a number of protection circuits such as overcharge protection and overdischarge protection, It has a function of shutting off the output of the battery pack in a predetermined case.

In many electronic devices using lithium ion secondary batteries, an overcharge protection or an overdischarge protection operation of the battery pack is performed by turning on / off the output using an FET switch built in the battery pack. However, when the FET switch is short-circuited for some reason, a lightning surge, etc. is applied, an instantaneous large current flows, or the output voltage drops abnormally due to the life of the battery cell. The battery pack and the electronic device must be protected from accidents such as ignition even when the is output. Therefore, a protective element made of a fuse element having a function of cutting off a current path by a signal from the outside is used in order to safely cut off the output of the battery cell in any possible abnormal state.

As a protection element of such a protection circuit for a lithium ion secondary battery or the like, as described in Patent Document 1, a heating element is provided inside the protection element. A structure that melts a molten conductor is generally used.

JP 2010-3665 A

In the protective element described in Patent Document 1, a fusible conductor (fuse) has a current capacity of about 15 A at the maximum in order to be used for an application having a relatively low current capacity such as a mobile phone or a notebook computer. ing. Applications of lithium ion secondary batteries have been expanding in recent years, and their use in higher current applications such as electric tools such as electric drivers, transportation equipment such as hybrid cars, electric vehicles, and electric power assisted bicycles has been studied. Part recruitment has begun. In these applications, a large current exceeding several tens of A to 100 A may flow particularly during startup. The realization of a protective element corresponding to such a large current capacity is desired.

In order to realize a protective element corresponding to a large current, the cross-sectional area of the soluble conductor may be increased. However, the protective element detects an overvoltage state of the battery cell in addition to the case where the battery is blown by an overcurrent state, and causes a current to flow through the heating element formed of the resistor, thereby cutting the soluble conductor by the heat generation. There is a need. If the cross-sectional area is increased in order to cope with a large current, the melting amount of the soluble conductor at the time of melting increases, so that it becomes difficult to stably melt the soluble conductor. Also, when the melting amount of the fusible conductor increases, the molten conductor also increases in agglomeration immediately before the current interruption due to overcurrent, and the molten conductor scatters a lot due to arc discharge at the time of interruption, resulting in a decrease in insulation resistance or fusibility. The risk of a short circuit in the peripheral circuit at the conductor mounting position is also increased. Another problem is that the fusing operation varies depending on the posture in which the protective element is arranged.

Therefore, an object of the present invention is to obtain a protection element and a battery pack that can suppress the scattering of a molten conductor due to arc discharge at the time of current interruption due to overcurrent while securing a current capacity at the time of overcurrent protection. It is another object of the present invention to provide a protection element and a battery pack that can reliably melt a soluble conductor by heat generated by a heating element while securing a current capacity during overcurrent protection.

A protection element according to the present invention that solves the above-described problem has a first insulating substrate and a soluble conductor mounted on the surface of the first insulating substrate, and is provided on the surface of the first insulating substrate. Are those in which suction holes for sucking the melted soluble conductor are opened.

The battery pack according to the present invention includes one or more battery cells and a protection element that is connected to the charge / discharge path of the battery cell and blocks the charge / discharge path. And a soluble conductor mounted on the surface of the first insulating substrate and serving as the charging / discharging path, and the surface of the first insulating substrate is suctioned to suck the molten soluble conductor A hole is opened.

The protective element according to the present invention includes the first and second external electrodes, the soluble conductor connected between the first and second external electrodes, and the molten conductor connected to the soluble conductor. A suction member that sucks the soluble conductor, and the suction member is formed on the surface of the first insulating substrate and the first insulating substrate disposed between the first and second external electrodes. A surface electrode connected to a part of the soluble conductor, a heating element provided on the first insulating substrate, and provided in the thickness direction of the first insulating substrate, and continuous with the surface electrode. A through-hole that cuts off a current path between the first external electrode and the second external electrode by melting the soluble conductor.

In addition, the battery pack according to the present invention detects one or more battery cells, a protection element that is connected to the charge / discharge path of the battery cell and blocks the charge / discharge path, and a voltage value of the battery cell. A current control element for controlling energization to the protection element, the protection element comprising: first and second external electrodes; a soluble conductor connected across the first and second external electrodes; A suction member that sucks the melted soluble conductor, and the suction member includes a first insulating substrate disposed between the first and second external electrodes, and the first insulating substrate. A surface electrode connected to a part of the soluble conductor, a heating element provided on the first insulating substrate, and a thickness direction of the first insulating substrate, It has a surface electrode and a continuous through hole, and the soluble conductor melts It is intended to further block the current path between the first external electrode and the second external electrode.

In addition, a protection element according to the present invention that solves the above-described problems includes the first insulating substrate, the first and second external electrodes, and the first insulating substrate on one surface side of the first insulating substrate. An intermediate electrode provided between the external electrode and the second external electrode, a heating element provided on the other surface side of the first insulating substrate, and one surface of the first insulating substrate Are connected to the intermediate electrode and connected to the first and second external electrodes, and a current path between the first external electrode and the second external electrode is heated by the heating element. A fusible conductor to be melted, a heating element lead electrode provided on the other surface side of the first insulating substrate and electrically connected to one terminal of the heating element, the intermediate electrode and the heating element lead Between the electrodes in the thickness direction of the first insulating substrate, and the intermediate power And and a through hole conductive layer is provided which is continuous with the heating element lead electrode.

The battery pack according to the present invention includes one or more battery cells, a protection element connected to cut off a current flowing through the battery cell, and a current for detecting the voltage value of each battery cell and heating the protection element. A current control element to be controlled. The protective element includes a first insulating substrate, first and second external electrodes, and the first external electrode and the second external electrode on one surface side of the first insulating substrate. And an intermediate electrode provided between the intermediate electrode, a heating element provided on the other surface of the first insulating substrate, and one surface of the first insulating substrate connected to the intermediate electrode. A soluble conductor connected across the first and second external electrodes and fusing a current path between the first external electrode and the second external electrode by heating by the heating element; and the first A heating element extraction electrode provided on the other surface side of the insulating substrate and electrically connected to one terminal of the heating element; and the first insulation between the intermediate electrode and the heating element extraction electrode. Provided in the thickness direction of the substrate, the inner surface is connected to the intermediate electrode and the heating element extraction electrode. And a through hole layer is provided.

According to the present invention, when the fusible conductor is melted, the melted fusible conductor is drawn into the suction holes formed in the first insulating substrate. . Therefore, even when the cross-sectional area of the fusible conductor is increased in order to improve the rating, the current path can be reliably cut.

FIG. 1 is a cross-sectional view showing a protection element to which the present invention is applied. FIG. 2 is a cross-sectional view showing a state in which a molten conductor is sucked in the protection element to which the present invention is applied. FIG. 3 is a cross-sectional view showing a state where a soluble conductor is blown in a protective element to which the present invention is applied. FIG. 4 is a block diagram illustrating a configuration example of a battery pack in which a protection element is used. FIG. 5 is a circuit diagram of a protection element to which the present invention is applied. FIG. 6 is a cross-sectional view showing a protection element having a heating element on the surface side of the first insulating substrate. FIG. 7 is a cross-sectional view showing a protection element having a heating element on the back side of the first insulating substrate. FIG. 8 is a cross-sectional view showing a protection element having a heating element in the first insulating substrate. FIG. 9 is a block diagram illustrating a configuration example of a battery pack in which a protection element is used. FIG. 10 is a circuit diagram of a protection element to which the present invention is applied. FIG. 11A is a plan view of a protection element to which the present invention is applied. FIG. 11B is a cross-sectional view taken along the line AA ′ of FIG. FIG. 12 is a block diagram showing an application example of a protection element to which the present invention is applied. FIG. 13 is a diagram showing a circuit configuration example of a protection element to which the present invention is applied. FIG. 14A is a cross-sectional view showing the operation of the heating element of the protection element to which the present invention is applied. FIG. 14B is a cross-sectional view showing a state where the fusible conductor is melted. FIGS. 15A to 15E are views showing the posture of the usage mode of the protection element to which the present invention is applied. FIG. 16 is a diagram showing fusing time of the soluble conductor in each posture of FIGS. 15 (A) to 15 (E). FIG. 17A is a plan view of a cohesive protection element as a reference example, and FIG. 17B is a cross-sectional view taken along the line AA ′ of FIG. FIG. 17C is a cross-sectional view of the melted state. 18 (A) to 18 (E) are views showing the posture in the usage mode of the protective element of the reference example shown in FIG. FIG. 19 is a diagram showing fusing time of the soluble conductor in each posture of FIGS. 18 (A) to 18 (E). FIG. 20 is a view showing a modification of the through holes provided in the intermediate electrode of the first insulating substrate, (A) shows an example in which the through holes are provided in two rows, and (B) shows the through holes. An example in which is used as a slit is shown. FIG. 21 is a cross-sectional view showing a protection element having a heating element on the surface side of the first insulating substrate. 22 (A) to 22 (E) are views showing postures of usage modes of the protection element to which the present invention is applied. FIG. 23 is a diagram showing fusing time of the soluble conductor in each posture of FIGS. 22 (A) to (E). FIG. 24 is a cross-sectional view showing a protective element provided with an aggregating member, where (A) shows the fusible conductor before fusing and (B) shows the fusible conductor after fusing. FIG. 25 is a circuit diagram showing a protection element provided with an aggregating member. FIG. 26 is a cross-sectional view showing a protection element having a plurality of suction members, where (A) shows before melting of the soluble conductor and (B) shows after melting of the soluble conductor. FIG. 27 is a circuit diagram showing a protection element having a plurality of suction members. FIG. 28 is a perspective view showing a soluble conductor having a high-melting-point metal layer and a low-melting-point metal layer and having a covering structure, and (A) is a structure in which the high-melting-point metal layer is an inner layer and is covered with a low-melting-point metal layer. (B) shows a structure in which a low melting point metal layer is used as an inner layer and is covered with a high melting point metal layer. FIG. 29 is a perspective view showing a fusible conductor having a laminated structure of a high melting point metal layer and a low melting point metal layer. . FIG. 30 is a cross-sectional view showing a soluble conductor having a multilayer structure of a high melting point metal layer and a low melting point metal layer. FIG. 31 is a plan view showing a soluble conductor in which a linear opening is formed on the surface of the refractory metal layer and the low melting point metal layer is exposed. FIG. 31A shows the opening along the longitudinal direction. The formed part (B) has an opening formed in the width direction. FIG. 32 is a plan view showing a soluble conductor in which a circular opening is formed on the surface of the high melting point metal layer and the low melting point metal layer is exposed. FIG. 33 is a plan view showing a soluble conductor in which a circular opening is formed in a refractory metal layer and a low melting metal is filled therein. FIG. 34 is a plan view showing a soluble conductor provided with a thick first side edge portion covered with a high melting point metal and a second side edge portion where the low melting point metal is exposed.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention.

[First Embodiment]
As shown in FIG. 1, the protection element 1 to which the present invention is applied includes a first insulating substrate 10 and a soluble conductor 13 mounted on a surface 10 a of the first insulating substrate 10. A suction hole 20 for sucking the melted soluble conductor 13 is formed in the surface 10a of the insulating substrate 10. The protection element 1 is incorporated in an external circuit, so that the fusible conductor 13 constitutes a part of the current path of the external circuit, and cuts off the current path by fusing due to overcurrent exceeding the rating. is there.

The first insulating substrate 10 is formed in a square shape by an insulating member such as alumina, glass ceramics, mullite, zirconia. In addition, the material used for printed wiring boards, such as a glass epoxy board | substrate and a phenol board | substrate, may be used for the 1st insulated substrate 10. FIG.

First and second electrodes 11 and 12 are formed at opposite ends of the surface 10 a of the first insulating substrate 10. The first and second electrodes 11 and 12 are each formed by a conductive pattern such as a Cu wiring, and a protective layer such as Sn plating is appropriately provided on the surface as an anti-oxidation measure. The first and second electrodes 11 and 12 are formed on the back surface 10b via the conductive layers 11b and 12b that reach the back surface 10b via the side surface of the first insulating substrate 10. The external connection electrodes 11a and 12a are connected. The protection element 1 is connected on the current path of the circuit board by connecting the first and second external connection electrodes 11a and 12a to the circuit board constituting the external circuit. And the protection element 1 mounts the soluble conductor 13 mentioned later over between the 1st, 2nd electrodes 11, 12, and the soluble conductor 13 makes the 1st, 2nd external connection electrodes 11a, 12a. And becomes part of the current path of the circuit board.

Further, the first insulating substrate 10 has a suction hole 20 formed between the first and second electrodes 11 and 12. When the fusible conductor 13 is melted by self-heating due to overcurrent, the suction hole 20 sucks the molten conductor 13a by capillary action and decreases the volume of the molten conductor 13a (see FIG. 2). The protective element 1 increases the cross-sectional area of the fusible conductor 13 in order to cope with a large current application, so that the suction hole 20 sucks the volume of the molten conductor 13a even when the melting amount increases. Can be reduced. Thereby, the protection element 1 reduces scattering of the molten conductor 13a due to arc discharge at the time of interruption, prevents a decrease in insulation resistance, and prevents a short circuit failure due to adhesion of the fusible conductor 13 to the peripheral circuit. Can be prevented.

The suction hole 20 has a conductive layer 21 formed on the inner surface. By forming the conductive layer 21, the suction hole 20 can easily suck the molten conductor 13 a. The conductive layer 21 is formed of, for example, copper, silver, gold, iron, nickel, palladium, lead, tin, or an alloy mainly containing any of them, and the inner surface of the suction hole 20 is made of electrolytic plating or conductive paste. It can be formed by a known method such as printing. Further, the conductive layer 21 may be formed by inserting a plurality of metal wires or a collection of conductive ribbons into the suction hole 20.

Further, the suction hole 20 is preferably formed as a through-hole penetrating in the thickness direction of the first insulating substrate 10. Thereby, the suction hole 20 can suck the molten conductor 13a to the back surface 10b side of the first insulating substrate 10, sucks more molten conductor 13a, and reduces the volume of the molten conductor 13a at the fusing site. be able to. Note that the suction hole 20 may be formed as a non-through hole.

A surface electrode 22 connected to the conductive layer 21 of the suction hole 20 is formed on the surface 10 a of the first insulating substrate 10. The surface electrode 22 serves as a support electrode to which the soluble conductor 13 is connected. Further, the surface electrode 22 is continuous with the conductive layer 21, so that when the soluble conductor 13 is melted, the molten conductor 13 a is aggregated and easily guided into the suction hole 20.

Further, a back surface electrode 23 connected to the conductive layer 21 of the suction hole 20 is formed on the back surface 10 b of the first insulating substrate 10. The back electrode 23 is continuous with the conductive layer 21, and when the soluble conductor 13 is melted, the molten conductor 13 a moved through the suction hole 20 is aggregated (see FIG. 3). Thereby, the protection element 1 can attract more molten conductor 13a, and can reduce the volume of the molten conductor 13a in a fusing part.

In addition, the protection element 1 increases the path | route which attracts | sucks the molten conductor 13a of the soluble conductor 13 by forming the suction hole 20 in multiple numbers, and attracts | sucks more molten conductor 13a, The molten conductor 13a in a fusing part You may make it reduce the volume of.

Next, the soluble conductor 13 will be described. The fusible conductor 13 is mounted between the first and second electrodes 11, 12, and is melted by self-heating (Joule heat) when a current exceeding the rating is applied, so that the first electrode 11 and the second electrode The current path to 12 is cut off.

The soluble conductor 13 may be any conductive material that melts in an overcurrent state. For example, in addition to SnAgCu-based Pb-free solder, BiPbSn alloy, BiPb alloy, BiSn alloy, SnPb alloy, PbIn alloy, ZnAl alloy, An InSn alloy, a PbAgSn alloy, or the like can be used.

Further, the soluble conductor 13 may be a structure containing a high melting point metal and a low melting point metal. For example, as shown in FIG. 1, the soluble conductor 13 is a laminated structure composed of an inner layer and an outer layer, and a low melting point metal layer 13b as an inner layer and a high melting point metal layer as an outer layer laminated on the low melting point metal layer 13b. 13c. The soluble conductor 13 is connected to the first and second electrodes 11 and 12 and the surface electrode 22 via a bonding material such as solder.

The low melting point metal layer 13b is preferably a metal mainly composed of solder or Sn, and is a material generally called “Pb-free solder” (for example, M705, manufactured by Senju Metal Industry). The melting point of the low melting point metal layer 13b is not necessarily higher than the temperature of the reflow furnace, and may be melted at about 200 ° C. The high melting point metal layer 13c is a metal layer laminated on the surface of the low melting point metal layer 13b. For example, the high melting point metal layer 13c is a metal mainly composed of Ag or Cu or any one of them. Therefore, even when mounting on an external circuit board, it has a high melting point that does not melt.

Such a soluble conductor 13 can be formed by depositing a high melting point metal layer on a low melting point metal foil using a plating technique, or using another known lamination technique or film forming technique. It can also be formed. The fusible conductor 13 may be constituted by a high melting point metal layer as an inner layer and a low melting point metal layer as an outer layer, or four or more layers in which low melting point metal layers and high melting point metal layers are alternately laminated. As will be described later, it can be formed in various configurations, such as a multilayer structure.

The soluble conductor 13 can be used even when the reflow temperature exceeds the melting temperature of the low melting point metal layer 13b by laminating the high melting point metal layer 13c as the outer layer on the low melting point metal layer 13b as the inner layer. The molten conductor 13 is not blown out. Therefore, the protection element 1 can be efficiently mounted by reflow.

Further, the fusible conductor 13 is not melted by self-heating while a predetermined rated current flows. When a current having a value higher than the rating flows, the current is melted by self-heating, and the current path between the first and second electrodes 11 and 12 is interrupted. At this time, the fusible conductor 13 is melted at a temperature lower than the melting temperature because the melted low melting point metal layer 13b erodes the high melting point metal layer 13c. Therefore, the soluble conductor 13 can be melted in a short time by utilizing the erosion action of the high melting point metal layer 13c by the low melting point metal layer 13b. Further, the molten conductor 13a of the soluble conductor 13 is divided by the physical drawing action of the surface electrode 22 and the first and second electrodes 11 and 12 in addition to the suction action by the suction hole 20 described above. The current path between the first and second electrodes 11 and 12 can be interrupted quickly and reliably.

Further, the fusible conductor 13 is formed by laminating a high melting point metal layer 13c on a low melting point metal layer 13b serving as an inner layer, so that the fusing temperature is significantly reduced compared to a chip fuse made of a conventional high melting point metal. can do. Therefore, the fusible conductor 13 can have a larger cross-sectional area and can greatly improve the current rating as compared to a chip fuse of the same size. In addition, it can be made smaller and thinner than conventional chip fuses having the same current rating, and is excellent in quick fusing.

Moreover, the fusible conductor 13 can improve the resistance (pulse resistance) to a surge in which an abnormally high voltage is instantaneously applied to the electrical system in which the protective element 1 is incorporated. That is, the fusible conductor 13 must not be blown until, for example, a current of 100 A flows for several milliseconds. In this respect, since a large current flowing in a very short time flows in the surface layer of the conductor (skin effect), the fusible conductor 13 is provided with a refractory metal layer 13c such as Ag plating having a low resistance value as the outer layer. The current applied by the surge can easily flow, and fusing due to self-heating can be prevented. Therefore, the fusible conductor 13 can greatly improve the resistance to surge as compared with a fuse made of a conventional solder alloy.

The fusible conductor 13 is coated with a flux 14 in order to prevent oxidation and improve wettability at the time of fusing. Further, the inside of the protection element 1 is protected by the first insulating substrate 10 being covered with the cover member 15. The cover member 15 can be formed using an insulating member such as a thermoplastic plastic, ceramics, glass epoxy substrate, or the like, similar to the first insulating substrate 10.

[Circuit configuration]
As shown in FIG. 4, such a protection element 1 is used by being incorporated in a circuit in a battery pack 30 of a lithium ion secondary battery, for example. The battery pack 30 has a battery stack 35 including battery cells 31 to 34 of a total of four lithium ion secondary batteries, for example.

The battery pack 30 includes a battery stack 35, a charge / discharge control circuit 40 that controls charging / discharging of the battery stack 35, a protection element 1 to which the present invention that cuts off charging when the battery stack 35 is abnormal, and each battery cell And a detection circuit 36 for detecting voltages 31 to 34.

The battery stack 35 is a series of battery cells 31 to 34 that need to be controlled to protect against overcharge and overdischarge states, and is detachable via the positive terminal 30a and the negative terminal 30b of the battery pack 30. Are connected to the charging device 45, and a charging voltage from the charging device 45 is applied thereto. The electronic device can be operated by connecting the positive electrode terminal 30a and the negative electrode terminal 30b of the battery pack 30 charged by the charging device 45 to an electronic device operating with a battery.

The charge / discharge control circuit 40 includes two current control elements 41 and 42 connected in series to a current path flowing from the battery stack 35 to the charging device 45, and a control unit 43 that controls the operation of these current control elements 41 and 42. Is provided. The current control elements 41 and 42 are configured by, for example, field effect transistors (hereinafter referred to as FETs), and control the gate voltage by the control unit 43 to control conduction and interruption of the current path of the battery stack 35. The control unit 43 operates by receiving power supply from the charging device 45, and controls the current so as to cut off the current path when the battery stack 35 is overdischarged or overcharged according to the detection result by the detection circuit 36. The operation of the elements 41 and 42 is controlled.

The protection element 1 is connected on a charge / discharge current path between the battery stack 35 and the charge / discharge control circuit 40, for example.

The detection circuit 36 is connected to the battery cells 31 to 34, detects the voltage values of the battery cells 31 to 34, and supplies the voltage values to the control unit 43 of the charge / discharge control circuit 40.

The protection element 1 to which the present invention is applied, used for the battery pack 30 having the above-described configuration, has a circuit configuration as shown in FIG. That is, in the protection element 1, the first external connection electrode 11a is connected to the battery stack 35 side, and the second external connection electrode 12a is connected to the positive electrode terminal 30a side. It is connected in series on the charge / discharge path.

[Operation of protection element]
When an overcurrent exceeding the rating is applied to the battery pack 30, the protection element 1 melts the fusible conductor 13 due to self-heating and blocks the charge / discharge path of the battery pack 30. At this time, as shown in FIGS. 2 and 3, the protection element 1 is soluble in order to cope with a large current application because the molten conductor 13 a is sucked into the suction hole 20 through the surface electrode 22 by capillary action. Even when the cross-sectional area of the conductor 13 is increased, the volume of the molten conductor 13a at the time of interruption can be reduced, and scattering of the molten conductor 13a due to arc discharge can be reduced. In addition, the protective element 1 is formed by including the high-melting point metal and the low-melting point metal so that the low-melting point metal is melted before the high-melting point metal is melted. The suction hole 20 can be sucked.

The protection element 1 according to the present invention is not limited to use in a battery pack of a lithium ion secondary battery, and can of course be applied to various uses that require interruption of a current path due to overcurrent.

[Heating element]
Further, as shown in FIG. 6, the protection element to which the present invention is applied may be provided with a heating element 25 for fusing the soluble conductor 13 on the first insulating substrate 10. In addition, in the following description, the same code | symbol is attached | subjected about the same member as the protection element 1 mentioned above, and the detail is abbreviate | omitted.

When the protective element 24 provided with the heating element 25 is incorporated in a battery pack, for example, in addition to self-melting of the fusible conductor 13 at the time of overcurrent, the overheating of the battery cell is detected to energize and heat the heating element 25. By melting the fusible conductor 13, the charge / discharge path of the battery pack can be shut off.

The heating element 25 is a conductive member that has a relatively high resistance value and generates heat when energized, and is made of, for example, W, Mo, Ru, or the like. These alloys, compositions, or compound powders mixed with a resin binder or the like to form a paste are patterned on the surface 10a of the first insulating substrate 10 using a screen printing technique and fired. It is formed by etc.

The heating element 25 is covered with an insulating layer 26 on the surface 10 a of the first insulating substrate 10. On the insulating layer 26, the surface electrode 22 is laminated. The insulating layer 26 is provided to protect and insulate the heating element 25 and to efficiently transmit the heat of the heating element 25 to the surface electrode 22 and the fusible conductor 13, and is made of, for example, a glass layer. By heating the surface electrode 22 by the heating element 25, the molten conductor 13 a of the soluble conductor 13 can be easily aggregated and can be easily sucked into the suction hole 20.

The heating element 25 is connected to the surface electrode 22 at one end and is electrically connected to the soluble conductor 13 mounted on the surface electrode 22 via the surface electrode 22. Further, the other end of the heating element 25 is connected to a heating element electrode (not shown). The heating element electrode is formed on the front surface 10a of the first insulating substrate 10 and is connected to a third external connection electrode 27 (see FIG. 9) formed on the back surface 10b. And connected to an external circuit. The protection element 1 is mounted on a circuit board constituting an external circuit, so that the heating element 25 is incorporated into a power supply path to the heating element 25 formed on the circuit board via the third external connection electrode 27. It is.

Further, as shown in FIG. 7, the protection element 24 may form the heating element 25 on the back surface 10 b of the first insulating substrate 10. The heating element 25 is formed on the back surface 10b of the first insulating substrate 10 and is covered with the insulating layer 26 on the back surface 10b. A back electrode 23 is laminated on the insulating layer 26.

One end of the heating element 25 is connected to the back electrode 23 and is electrically connected to the soluble conductor 13 mounted on the surface electrode 22 through the conductive layer 21 and the surface electrode 22 formed in the suction hole 20. The The other end of the heating element 25 is connected to the third external connection electrode 27 via a heating element electrode (not shown).

By forming the heating element 25 on the back surface 10b of the first insulating substrate 10, the protective element 24 is likely to aggregate more molten conductors 13a when the back electrode 23 is heated by the heating element 25. Therefore, the protective element 24 can promote the action of attracting the molten conductor 13a from the front electrode 22 to the back electrode 23 via the conductive layer 21, and can reliably melt the soluble conductor 13.

Further, as shown in FIG. 8, the protective element 24 may form the heating element 25 inside the first insulating substrate 10. In this case, the heating element 25 does not need to be covered with an insulating layer such as glass. Further, one end of the heating element 25 is connected to the front surface electrode 22 or the back surface electrode 23, and is electrically connected to the soluble conductor 13 mounted on the front surface electrode 22. The other end of the heating element 25 is connected to the third external connection electrode 27 via a heating element electrode (not shown).

By forming the heating element 25 inside the first insulating substrate 10, the protective element 24 has more surface elements 22 and 23 that are heated by the heating element 25 through the conductive layer 21, thereby increasing the number of the heating elements 25. It becomes easy to agglomerate the molten conductor 13a. Therefore, the protective element 24 can promote the action of attracting the molten conductor 13a from the front electrode 22 to the back electrode 23 via the conductive layer 21, and can reliably melt the soluble conductor 13.

Note that the heating element 25 can be formed on both sides of the suction hole 20 to heat the front electrode 22 and the back electrode 23 in any case formed on the front surface 10b, the back surface 10b, or the inside of the first insulating substrate 10. In addition, it is preferable for agglomerating and sucking more molten conductor 13a.

[Circuit configuration]
As shown in FIG. 9, such a protection element 24 is used by being incorporated in a circuit in a battery pack 30 of a lithium ion secondary battery, for example. In the following description, the same members as those of the above-described battery pack 30 are denoted by the same reference numerals and the details thereof are omitted.

The battery pack 30 includes a battery stack 35, a charge / discharge control circuit 40 that controls charging / discharging of the battery stack 35, a protection element 24 to which the present invention that cuts off charging when the battery stack 35 is abnormal, and each battery cell. A detection circuit 36 for detecting voltages 31 to 34 and a current control element 37 serving as a switch element for controlling the operation of the protection element 24 according to the detection result of the detection circuit 36 are provided.

The protection element 24 is connected to, for example, a charge / discharge current path between the battery stack 35 and the charge / discharge control circuit 40, and its operation is controlled by the current control element 37.

The detection circuit 36 is connected to the battery cells 31 to 34, detects the voltage values of the battery cells 31 to 34, and supplies the voltage values to the control unit 43 of the charge / discharge control circuit 40. The detection circuit 36 outputs a control signal for controlling the current control element 37 when any one of the battery cells 31 to 34 becomes an overcharge voltage or an overdischarge voltage.

The current control element 37 is constituted by, for example, an FET, and when the voltage value of the battery cells 31 to 34 exceeds a predetermined overdischarge or overcharge state by a detection signal output from the detection circuit 36, the current control element 37 is a protection element. 24 is operated to control the charge / discharge current path of the battery stack 35 to be cut off regardless of the switch operation of the current control elements 41 and 42.

The protection element 24 to which the present invention is applied, which is used in the battery pack 30 having the above-described configuration, has a circuit configuration as shown in FIG. That is, the protective element 24 has the first external connection electrode 11a connected to the battery stack 35 side, and the second external connection electrode 12a connected to the positive electrode terminal 30a side. It is connected in series on the charge / discharge path. Further, the protection element 24 has the heating element 25 connected to the current control element 37 via the heating element electrode and the third external connection electrode 27, and the heating element 25 is connected to the open end of the battery stack 35. Thereby, one end of the heating element 25 is connected to one open end of the fusible conductor 13 and the battery stack 35 via the surface electrode 22, and the other end is connected to the current control element 37 via the third external connection electrode 27. In addition, a power supply path to the heating element 25 that is connected to the other open end of the battery stack 35 and whose energization is controlled by the current control element 37 is formed.

[Operation of protection element]
When an overcurrent exceeding the rating is applied to the battery pack 30, the protection element 24 melts the fusible conductor 13 due to self-heating and blocks the charge / discharge path of the battery pack 30. At this time, when the molten conductor 13a is sucked into the suction hole 20 through the surface electrode 22 by capillary action, the protective element 24 increases the cross-sectional area of the soluble conductor 13 in order to cope with a large current application. In addition, the volume of the molten conductor 13a at the time of interruption can be reduced, and scattering of the molten conductor 13a due to arc discharge can be reduced. In addition, the protective element 24 is formed by including the high-melting point metal and the low-melting point metal so that the low-melting point metal is melted before the high-melting point metal is melted. The suction hole 20 can be sucked.

Further, when the detection circuit 36 detects any abnormal voltage of the battery cells 31 to 34, it outputs a cutoff signal to the current control element 37. Then, the current control element 37 controls the current so that the heating element 25 is energized. In the protection element 24, a current flows from the battery stack 35 to the heating element 25 via the first electrode 11, the soluble conductor 13, and the surface electrode 22, whereby the heating element 25 starts to generate heat. In the protection element 24, the fusible conductor 13 is melted by the heat generated by the heating element 25, and the charge / discharge path of the battery stack 35 is blocked.

At this time, when the molten conductor 13a is sucked into the suction hole 20 through the surface electrode 22 by capillary action, the protective element 24 increases the cross-sectional area of the soluble conductor 13 in order to cope with a large current application. In addition, the charging / discharging path of the battery pack 30 can be reliably interrupted. In addition, the protective element 24 is formed by melting the meltable conductor 13 containing a high-melting point metal and a low-melting point metal so that the high-melting point metal is melted by a molten low-melting point metal in a short time. can do.

In addition, since the power supply path | route to the heat generating body 25 is also interrupted | blocked by the fusible conductor 13, the protection element 24 stops the heat_generation | fever of the heat generating body 25. FIG.

The protection element 24 according to the present invention is not limited to use in a battery pack of a lithium ion secondary battery, but can of course be applied to various uses that require interruption of a current path by an electric signal.

[Second Embodiment]
[Configuration of protection element]
Next, a second embodiment will be described. As shown in FIG. 11A and FIG. 11B, the protection element 50 is laminated between the first and second external electrodes 51 and 52 and the first and second external electrodes 51 and 52. A fusible conductor 53 and a suction member 54 connected to the fusible conductor 53 and sucking the molten conductor 53a of the fusible conductor 53 are provided. The suction member 54 includes an insulating substrate 55 disposed between the first and second external electrodes 51 and 52, and a surface electrode formed on the surface 55 a of the insulating substrate 55 and connected to a part of the soluble conductor 53. 56, a heating element 57 provided on the insulating substrate 55, and a through hole 58 provided in the thickness direction of the insulating substrate 55 and continuous with the surface electrode 56. The protection element 50 melts the soluble conductor 53 when the heating element 57 generates heat. At this time, the protection element 50 sucks the melted conductor 53a in which the soluble conductor 53 is melted by the suction member 54, reliably blows the soluble conductor 53, and the first external electrode 51 and the second external electrode 52 The current path between is interrupted.

The first and second external electrodes 51 and 52 are connection terminals for connecting the protection element 50 to an external circuit, and are connected to each other through a soluble conductor 53 inside the protection element 50. The first and second external electrodes 51 and 52 are disposed on the inside and outside of the protection element 50 by being supported by the outer casing of the protection element 50. The first and second external electrodes 51 and 52 may be formed on the insulating substrate 55 of the suction member 54, or formed of an insulating material made of an epoxy resin or the like adjacent to or integrated with the insulating substrate 55. You may make it do.

The fusible conductor 53 is melted by an overcurrent state and by the heat generated by the heating element 57. Therefore, any conductive material that melts may be used. For example, SnAgCu-based Pb-free solder, BiPbSn alloy BiPb alloy, BiSn alloy, SnPb alloy, PbIn alloy, ZnAl alloy, InSn alloy, PbAgSn alloy, or the like can be used. Note that the soluble conductor 53 may be a laminate of a high melting point metal made of a metal mainly composed of Ag or Cu or Ag or Cu and a low melting point metal such as Pb-free solder mainly composed of Sn. In addition, it can be formed in various configurations, as will be described later, such as a multi-layer structure of four or more layers in which low melting point metal layers and high melting point metal layers are alternately laminated.

The insulating substrate 55 is formed of an insulating member such as alumina, glass ceramics, mullite, zirconia, or the like. In addition, although the material used for printed wiring boards, such as a glass epoxy board | substrate and a phenol board | substrate, may be used, it is necessary to pay attention to the temperature at the time of fuse blowing.

The heating element 57 is a conductive member that has a relatively high resistance value and generates heat when energized, and is made of, for example, W, Mo, Ru, or the like. By mixing powders of these alloys, compositions, or compounds with a resin binder or the like and forming a paste on the back surface 55b of the insulating substrate 55 using a screen printing technique, firing, etc. Form. Both ends of the heating element 57 are connected to the first and second heating element electrodes 59 and 60. The first and second heating element electrodes 59, 60 are provided on the back surface 55 b of the same insulating substrate 55 as the heating element 57. The first heating element electrode 59 is connected to the soluble conductor 53 via a heating element extraction electrode 63 described later, and the second heating element electrode 60 is connected to the third external connection electrode 61 (see FIGS. 12 and 13). Thus, the heating element 57 is connected to a power source for generating heat.

The heating element 57 is covered with an insulating member 62 such as glass, and the heating element extraction electrode 63 is disposed so as to face the heating element 57 through the insulating member 62. The insulating member 62 may be a laminated substrate in which the heating elements 57 are integrally laminated. Further, the heating element 57 may be provided only on one side of the back electrode 64 or so as to surround the back electrode 64 in addition to being provided on both sides of the back electrode 64 described later.

A surface electrode 56 is formed on the surface 55 a of the insulating substrate 55. The surface electrode 56 is connected to a soluble conductor 53 that connects between the first and second external electrodes 51 and 52 via a connection material such as solder. The surface electrode 56 is continuous with a through hole 58 formed in the thickness direction of the insulating substrate 55. When the soluble conductor 53 is melted by the heat generated by the heating element 57, the surface electrode 56 can be agglomerated and melted into the through hole 58 by capillary action. Thereby, the protection element 50 does not excessively aggregate the molten conductor 53a on the surface 55a of the insulating substrate 55 even when the cross-sectional area of the soluble conductor 53 is increased in order to cope with a large current application. The current path between the first and second external electrodes 51 and 52 can be cut off reliably.

As shown in FIG. 11A, the through hole 58 is provided in the center in the width direction of the surface electrode 56. A plurality of through holes 58 may be provided. Here, a plurality of through holes 58 are provided in a line in a straight line.

A conductive layer 65 continuous with the surface electrode 56 is provided on the inner peripheral surface of the through hole 58. The conductive layer 65 is, for example, a metal material in which the molten conductor 53a spreads and is formed by a paste process, a plating process, or the like. Accordingly, the protection element 50 can easily draw the molten conductor 53a aggregated on the surface electrode 56 into the through hole 58, and can attract more molten conductor 53a.

Further, the protective element 50 is provided with a back electrode 64 that is continuous with the through hole 58 and the conductive layer 65 on the back surface 55 b of the insulating substrate 55. By providing the back surface electrode 64, the protective element 50 causes the molten conductor 53a sucked into the through-hole 58 through the conductive layer 65 to be aggregated into the back surface electrode 64, so that more molten conductor 53a is attracted. be able to.

Further, as described above, the heating element 57 described above is provided in the vicinity of the back electrode 64, for example, on both sides, one side, or the periphery. Thereby, the heat of the heat generating body 57 is efficiently transmitted to the back surface electrode 64, the conductive layer 65, and the surface electrode 56, and the protection element 50 can heat and melt the soluble conductor 53 quickly.

In addition, the protective element 50 is partially or entirely filled with the same or similar material as the soluble conductor 53 or the preliminary solder 66 having a melting point lower than that of the soluble conductor 53. When the heating element 57 generates heat, the spare solder 66 has a temperature on the back surface 55b side of the insulating substrate 55 higher than that on the front surface 55a side, and further, the conductive layer 65, the surface electrode 56, the back electrode 64, and the heating element lead electrode. When the temperature of 63 is increased before the insulating substrate 55, it is melted before the soluble conductor 53, and then the molten conductor 53 a can be called into the through hole 58. As a result, the molten conductor 53a moves from the front surface 55a to the back surface 55b of the insulating substrate 55, and reliably blocks the current path between the first external electrode 51 and the second external electrode 52 regardless of the posture. be able to.

The heating element extraction electrode 63 provided on the back surface 55b of the insulating substrate 55 is overlapped with and electrically connected to the back surface electrode 64 of the back surface 55b. The heating element extraction electrode 63 is connected to the fusible conductor 53 through the back electrode 64, the through hole 58, the preliminary solder 66, and the front electrode 56, and a tab 63a formed at one end includes the first heating element electrode 59. It is connected to the.

Note that island electrodes 67 a and 67 b are provided outside the surface electrode 56 on the surface 55 a of the insulating substrate 55 so as to be separated from each other. When the fusible conductor 53 is melted, the island electrodes 67a and 67b hold a part of the molten conductor 53a apart from the surface electrode 56 and the first and second external electrodes 51 and 52 by wettability. .

In the protection element 50 as described above, by providing the heating element 57 on the back surface 55b side of the insulating substrate 55, when the heating element 57 generates heat, the temperature of the back surface 55b side becomes higher than that of the front surface 55a side. In addition, the conductive layer 65, the front surface electrode 56, the back surface electrode 64, and the heating element extraction electrode 63 are generally conductive materials such as a copper pattern and have excellent thermal conductivity. Further, the back surface electrode 64 of the back surface 55b is provided between the heat generating elements 57, and the heat of the heat generating elements 57 is efficiently transmitted. Therefore, the protection element 50 can attract more molten conductor 53a to the back surface 55b side of the insulating substrate 55, increase the cross-sectional area of the soluble conductor 53 to cope with a large current, and melt at the time of fusing Even when the amount of melting of the conductor 53a increases, the soluble conductor 53 can be stably blown.

Further, in the protection element 50, the preliminary solder 66 is filled in the through hole 58 so that the temperature of the conductive layer 65, the front surface electrode 56, the back surface electrode 64, and the heating element extraction electrode 63 becomes higher than the insulating substrate 55. Thus, the preliminary solder 66 is melted before the fusible conductor 53, and the molten conductor 53 a can be called into the through hole 58. As a result, the molten conductor 53a is efficiently sucked from the front surface 55a to the back surface 55b of the insulating substrate 55, and the current path between the first external electrode 51 and the second external electrode 52 is ensured regardless of the posture. Can be blocked. The suction member 54 may be filled with a part or all of the flux in the through hole 58 together with the spare solder 66 or instead of the spare solder 66. Also by filling the flux, the wettability of the soluble conductor 53 can be improved, and the molten conductor 53a can be efficiently drawn into the through hole 58.

[How to use protection elements]
As shown in FIG. 12, the protection element 50 is used in a circuit in the battery pack 30 of the above-described lithium ion secondary battery. Similarly to the protection element 10, the protection element 50 is connected on a charge / discharge current path between the battery stack 31 and the charge / discharge control circuit 32, and its operation is controlled by the current control element 34.

In the battery pack 30, the protection element 50 has a circuit configuration as shown in FIG. That is, the protective element 50 is connected between the first and second external electrodes 51 and 52 and is connected to the surface electrode 56 formed on the surface 55 a of the insulating substrate 55, and the surface electrode 56. This is a circuit configuration comprising a heating element 57 that melts the soluble conductor 53 by being energized and heated via the. One end of the heating element 57 is connected to the surface electrode 56 via the first heating element electrode 59, the heating element extraction electrode 63, the back surface electrode 64 and the conductive layer 65, and the other end via the second heating element electrode 60. Connected to the third external connection electrode 61. In the protection element 50, the soluble conductor 53 is connected in series on the charge / discharge current path between the first and second external electrodes 51, 52, and the heating element 57 is connected to the soluble conductor 53 via the surface electrode 56. At the same time, it is connected to the current control element 34 via the third external connection electrode 61.

In the battery pack 30 having such a circuit configuration, when the voltage value of the battery cells 31 to 34 exceeds a predetermined overdischarge or overcharge state, the current control element 37 operates the protection element 50, Control is performed so that the charge / discharge current path of the battery stack 35 is cut off regardless of the switching operation of the current control elements 41 and 42. Specifically, in the protection element 50, the heating element 57 generates heat, and the soluble conductor 53 and the preliminary solder 66 in the through hole 58 are heated as shown in FIG. At this time, the insulating substrate 55 has a temperature gradient in which the temperature on the back surface 55b side where the heating element 57 is disposed is higher than that on the front surface 55a side. The back electrode 64 on the back surface 55b side of the insulating substrate 55, the heating element extraction electrode 63, the conductive layer 65 of the through hole 58, and the surface electrode 56 of the surface 55a of the insulating substrate 55 are superior in thermal conductivity to the insulating substrate 55 such as ceramic. .

Therefore, the heat of the heating element 57 mainly includes the back surface electrode 64 provided between the heating elements 57, the heating element extraction electrode 63 on the heating element 57, the conductive layer 65 of the through hole 58, and the surface electrode 56 of the surface 55a. In this path, it is transmitted to the surface 55a of the insulating substrate 55, and the spare solder 66 and the soluble conductor 53 in the path are melted. Of course, the fusible conductor 53 is inefficient, but is also melted by heat transmitted through an insulating layer such as a ceramic of the insulating substrate 55. As a result, as shown in FIG. 14B, the spare solder 66 starts to melt before the soluble conductor 53 and gradually gets wet with the front electrode 56, the conductive layer 65, the back electrode 64, and the heating element extraction electrode 63. The fusible conductor 53 that has moved to the back surface 11b of the insulating substrate 55 and melted behind the spare solder 66 also moves so as to be dragged to the back surface 55b side of the insulating substrate 55 through the through hole 58 due to wettability. To do. Part of the molten conductor 53a is also held by the island-shaped electrodes 67a and 67b on the surface 55a of the insulating substrate 55 (see the arrow in FIG. 14A). Thereby, the protection element 50 can surely melt the soluble conductor 53 on the current path between the first and second external electrodes 51 and 52.

As described above, the protective element 50 of the present invention can easily melt the soluble conductor 53 by guiding a large amount of the soluble conductor 53 (solder) from the front surface 55a of the insulating substrate 55 to the back surface 55b. Here, in order to confirm whether the soluble conductor 53 can be stably melted regardless of the posture in which the protective element 50 is disposed, experiments shown in FIGS. 15 and 16 were performed. Here, FIG. 16 shows the relationship between each posture of the protection element 50 of the present invention shown in FIGS. 15A to 15E and the fusing time. Here, the protection element 50 is operated at 15 W.

FIG. 15A is a plan view showing a state after fusing of the protective element 50 placed with the front surface 55a side of the insulating substrate 55 facing upward and the back surface 55b side of the insulating substrate 55 facing downward.
15B shows that the protective element 50 is inverted 90 ° from the position shown in FIG. 15A and the through hole 58 is directed horizontally, and the second external electrode 52 faces upward and is soluble in the vertical direction. FIG. 5 is a side view showing a state after the protective element 50 supporting the conductor 53 is melted.
15C is further rotated by 90 ° from the posture of FIG. 15B, the through-holes 58 are juxtaposed in the vertical direction, and the protection element 50 that supports the fusible conductor 53 in the horizontal direction is blown out. It is a side view which shows a state.
FIG. 15D shows a state in which the posture of FIG. That is, it is a plan view showing a state after fusing of the protection element 50 placed with the front surface 55a side of the insulating substrate 55 facing downward and the back surface 55b side of the insulating substrate 55 facing upward.
FIG. 15E shows that the insulating substrate 55 is rotated 45 ° in the in-plane direction from the posture in which the first external electrode 51 is turned upside down, and the through-holes 58 are diagonally arranged, and the fusible conductor 53 is It is a side view which shows the state after fusing of the protection element 50 supported diagonally.

As shown in FIG. 16, it can be confirmed that the protection element 50 of the present invention has no variation in the fusing time and can surely melt the soluble conductor 53 in any posture.

FIG. 17 shows a protective element 100 which is a comparative example of the present invention, which is of the aggregation type. As shown in FIGS. 17A and 17B, the protection element 100 includes an insulating substrate 101, first and second external electrodes 102 and 103 formed on the end of the surface 101a of the insulating substrate 101, The heating element 104 provided on the surface 101 a of the insulating substrate 101 and the first and second external electrodes 102 and 103 are stacked, traverse the heating element 104, and heated by the heating element 104, thereby heating the first external electrode 102. And a soluble conductor 105 for fusing a current path between the first external electrode 103 and the second external electrode 103. The heating element 104 is provided at both ends on the surface 101a of the insulating substrate 101, and is connected to first and second heating element electrodes 106 and 107 for connecting a power source to cause the heating element 104 to generate current by flowing current. .

The first and second heating element electrodes 106 and 107 are formed on the surface 101 a of the insulating substrate 101. The first heating element electrode 106 is connected to the heating element 104 and to the tab 108a of the heating element extraction electrode 108. The second heating element electrode 107 is connected to the heating element 104 and to an external connection electrode (not shown).

The heating element extraction electrode 108 has one end connected to the fusible conductor 105 and the other end connected to the first heating element electrode 106 by a tab 108a of the heating element extraction electrode 108. In addition, island electrodes 109 a and 109 b are provided outside the heating element 104 so as to be separated from the heating element 104. When the fusible conductor 105 is melted, the island- like electrodes 109a and 109b hold the molten conductor 105a in which the fusible conductor 105 is melted due to wettability, and the first electrode 102 and the second outer electrode 103 are Fuse the current path between. That is, in the protection element 100, the through hole is not provided in the insulating substrate 101, and the molten conductor 105a does not move to the back surface 101b of the insulating substrate 101.

The protection element 100 is also used in the same manner as the protection element 50. As shown in FIG. 12, the voltage values of the battery cells 31 to 34 are set to a predetermined overdischarge or overload by the detection signal output from the detection circuit 36. When the voltage exceeds the charged state, the current control element 37 operates the protection element 100 to cut off the charge / discharge current path of the battery stack 35 regardless of the switching operation of the current control elements 41 and 42. As a result, the heating element 104 generates heat and melts the fusible conductor 105 as shown in FIG. 17C, and a part of the molten conductor 105a is held by the island-shaped electrodes 109a and 109b to interrupt the current path. To do.

FIG. 19 shows the relationship between the posture of the protective element 100 as a reference example and the fusing time. Here, the protection element 100 is operated at 15 W. Further, each posture in FIGS. 18A to 18E corresponds to each posture in FIGS. 15A to 15E.

18A is a plan view showing a state after fusing of the protection element 100 placed with the front surface 101a side of the insulating substrate 101 facing upward and the back surface 101b side of the insulating substrate 101 facing downward.
FIG. 18B shows the protection element 100 in which the protection element 100 is inverted 90 degrees from the posture of FIG. 18A and the soluble conductor 105 is supported in the vertical direction with the first external electrode 102 facing upward. It is a side view which shows the state after fusing.
FIG. 18C is a side view showing a state after the fusing of the protective element 100 that further rotates 90 ° from the posture of FIG. 18B and supports the fusible conductor 105 in the horizontal direction.
FIG. 18D illustrates a state in which the posture illustrated in FIG. That is, it is a plan view showing a state after fusing of the protection element 100 placed with the front surface 101a side of the insulating substrate 101 facing downward and the back surface 101b side of the insulating substrate 101 facing upward.
FIG. 18E shows a state in which the insulating substrate 101 is rotated 45 ° in the in-plane direction from the posture in which the first external electrode 102 is turned upside down, and the protective element 100 that supports the fusible conductor 105 obliquely is blown. It is a side view which shows the state.
FIG. 19 shows the fusing time of the fusible conductor 105 when the protective element 100 of the present invention is in the posture shown in FIGS. 18 (A)-(E).

As shown in FIG. 19, it can be confirmed that the protection element 100 of the comparative example has a large variation in the fusing time depending on the wiring posture of the protection element 100. That is, the protection element 50 of the present invention can reduce the variation in fusing time regardless of the posture as compared with the protection device 100 of the reference example, and thus can be reliably performed in a substantially constant time regardless of the posture. The molten conductor 53 can be blown.

As shown in FIG. 20, the through holes 58 may be provided in two rows as shown in FIG. 20A, in addition to the case where the through holes 58 are provided in a straight line as shown in FIG. 11B. More than that may be provided. Further, as shown in FIG. 20 (B), it may be constituted by an elongated slit 58a instead of a plurality of through holes, or may be plural.

[Heating element]
Further, as shown in FIG. 21, the protection element to which the present invention is applied may use a suction member 70 in which a heating element 57 is formed on the surface 55a side of the insulating substrate 55. In the following description, the same members as those of the protection element 50 described above are denoted by the same reference numerals and their details are omitted. The protection element 71 using the suction member 70 in which the heating element 57 is formed on the surface 55 a side of the insulating substrate 55 is covered with the insulating member 62 while the heating element 57 is formed on the surface 55 a of the insulating substrate 55. .

The heat generating element 57 is connected to the first and second heat generating element electrodes 59 and 60 formed on the surface 55a of the insulating substrate 55 at both ends. The first heating element electrode 59 is connected to the soluble conductor 53 via the heating element extraction electrode 63, whereby the heating element 57 is connected to the soluble conductor 53. In addition, the second heating element electrode 60 is connected to a third external connection electrode 61 (see FIGS. 12 and 13), whereby the heating element 57 is connected to a power source for generating heat.

The heating element 57 is covered with an insulating member 62, and the heating element extraction electrode 63 is disposed so as to face the heating element 57 through the insulating member 62. The insulating member 62 may be a laminated substrate in which the heating elements 57 are integrally laminated. Further, the heating element 57 may be provided only on one side of the surface electrode 56 or so as to surround the surface electrode 56 in addition to being provided on both sides of the surface electrode 56.

The heating element extraction electrode 63 is formed on the surface 55 a of the insulating substrate 55 so as to overlap the heating element 57 with the insulating member 62 interposed therebetween. The heating element extraction electrode 63 is connected to the soluble conductor 53 via the surface electrode 56, and a tab 63 a formed at one end is connected to the first heating element electrode 59.

The protective element 71 has a through hole 58 formed in the same manner as the protective element 50 described above, and is provided with a conductive layer 65 and a back electrode 64, and a part or all of the through hole 58 is filled with spare solder 66. You may let them. Further, the suction member 70 may be filled with a part or all of the flux in the through hole 58 together with the spare solder 66 or instead of the spare solder 66. Also by filling the flux, the wettability of the soluble conductor 53 can be improved, and the molten conductor 53a can be efficiently drawn into the through hole 58.

By providing the heating element 57 on the surface 55a side of the insulating substrate 55, the protection element 71 can efficiently transmit the heat to the soluble conductor 53 when the heating element 57 generates heat, and promptly attach the soluble conductor 53 to the soluble element 53. Can be blown. Further, in the protective element 71, in the initial stage of heat generation, the temperature 55a of the insulating substrate 55 has a temperature gradient higher than that of the back surface 55b. Therefore, the protective element 71 can cause the molten conductor 53a to agglomerate on the high temperature surface electrode 56 and to be quickly sucked into the through hole 58 through the conductive layer 65 continuous with the surface electrode 56, and the cross-sectional area can be increased. Even when a large amount of the molten conductor 53a is melted, the soluble conductor 53 can be surely blown.

[Example]
As described above, the protective element 71 of the present invention can easily melt the soluble conductor 53 by guiding a large amount of the soluble conductor 53 from the front surface 55a of the insulating substrate 55 to the back surface 55b. Here, in order to confirm whether the soluble conductor 53 can be stably melted regardless of the posture in which the protective element 71 is disposed, experiments shown in FIGS. 22 and 23 were performed. In the protective element 71 used in the experiment, a 0.85φ through-hole 58 was formed in an alumina-based substrate having a thickness of 0.635 mm as the insulating substrate 55, and the inner surface was subjected to Ni / Au plating. Further, as the soluble conductor 53, a Sn-Ag-Cu-based metal foil having a thickness of 0.35 mm was subjected to an Ag plating process having a thickness of 6 μm.

When the protective element 71 was operated at 31 W, the fusing time of the fusible conductor 53 in each posture shown in FIG. 22 was measured. Here, FIG. 23 shows the relationship between each posture of the protection element 71 of the present invention shown in FIGS. 22A to 22E and the fusing time. Each posture in FIGS. 22A to 22E corresponds to each posture in FIGS. 15A to 15E.

22A is a plan view showing a state after the fusing of the protective element 71 placed with the front surface 55a side of the insulating substrate 55 facing upward and the back surface 55b side of the insulating substrate 55 facing downward.
22B, the protective element 71 is inverted 90 ° from the posture of FIG. 22A to direct the through hole 58 in the horizontal direction, and the second external electrode 52 is directed upward to be soluble in the vertical direction. FIG. 7 is a side view showing a state after the protection element 71 supporting the conductor 53 is melted.
22C is further rotated by 90 ° from the posture of FIG. 22B, the through-holes 58 are arranged in parallel in the vertical direction, and the protective element 71 that supports the fusible conductor 53 in the horizontal direction is blown out. It is a side view which shows a state.
FIG. 22D shows a state in which the posture of FIG. That is, it is a plan view showing a state after fusing of the protective element 71 placed with the front surface 55a side of the insulating substrate 55 facing downward and the back surface 55b side of the insulating substrate 55 facing upward.
FIG. 22E shows that the insulating substrate 55 is rotated by 45 ° in the in-plane direction from the posture in which the second external electrode 52 is turned upside down, and the through-holes 58 are obliquely arranged in parallel, and the fusible conductor 53 is It is a side view which shows the state after fusing of the protection element 71 supported diagonally.

As shown in FIG. 23, it can be confirmed that the protective element 71 of the present invention has no variation in the fusing time and can surely melt the soluble conductor 53 in any posture.

The protective element to which the present invention is applied may be formed inside the insulating substrate 55 in addition to forming the heating element 57 on the front surface 55a and the back surface 55b of the insulating substrate 55. In this case, the heating element 57 does not need to be covered with the insulating member 62, and the heating element 57 is connected to the front surface electrode 56 or the back surface electrode 64 through the conductive layer 65.

[Aggregating member]
In addition to the suction members 54 and 70, the protective element to which the present invention is applied may be used in combination with an aggregating member 75 that agglomerates the molten conductor 53 a and assists the melting of the soluble conductor 53. 24A and 24B are cross-sectional views of a protective element 74 using the suction member 70 and the aggregation member 75 in combination. As shown in FIGS. 24A and 24B, the aggregating member 75 covers the second insulating substrate 76, the heating element 77 provided on the surface 76a of the second insulating substrate 76, and the heating element 77. And a collecting electrode 79 that is laminated on the insulating member 78 and aggregates the molten conductor 53a.

The aggregating member 75 can use the same members as the insulating substrate 55, the heating element 57 and the insulating member 62 of the protection element 50 as the second insulating substrate 76, the heating element 77 and the insulating member 78. The collector electrode 79 can be formed by printing and baking a high melting point metal paste such as Ag or Cu.

FIG. 25 shows a circuit diagram of the protection element 74. Like the heat generating element 57, the aggregating member 75 has a heat generating element 77 electrically connected to the third external connection electrode 61 via a heat generating element electrode (not shown), and a current control element 37 provided in an external circuit. The energization is controlled in conjunction with the heating element 57 of the suction member 70. Further, the aggregating member 75 has a heating element 77 connected to a collecting electrode 79 via a heating element electrode (not shown), and is electrically connected to the soluble conductor 53 via the collecting electrode 79.

In the aggregating member 75, the collector electrode 79 is connected to the surface opposite to the surface on which the suction member 70 of the soluble conductor 53 is provided. Therefore, when the heating element 57 of the suction member 70 is energized and heated, the protection element 74 energizes and generates heat at the same time as the heating element 77 of the aggregating member 75 and heats the fusible conductor 53 from both sides. Melt.

At this time, the protection element 74 sucks the molten conductor 53a into the through-hole 58 by the suction member 70, and agglomerates the molten conductor 53a to the collector electrode 79 by the aggregation member 75, thereby sucking and holding the molten conductor 53a. The tolerance is increased. Therefore, the protective element 74 can be surely blown even when a large amount of the molten conductor 53a is generated using the soluble conductor 53 having a large cross-sectional area and a high rating, while improving the rating. The fusing characteristics can be maintained and improved.

Also, the protective element 74 can quickly melt the soluble conductor 53 even when a covering structure in which the low melting point metal constituting the inner layer is covered with the high melting point metal is used as the soluble conductor 53. That is, the soluble conductor 53 covered with the refractory metal takes time to be heated to a temperature at which the outer refractory metal melts even when the heating elements 57 and 77 generate heat. Here, the protective element 74 includes the suction member 54 and the aggregating member 75, and simultaneously heats the heating elements 57 and 77, so that the refractory metal in the outer layer can be quickly heated to the melting temperature. Therefore, according to the protective element 74, the thickness of the refractory metal layer constituting the outer layer can be increased, and the fast fusing characteristics can be maintained while further increasing the rating.

Further, the protective element 74 preferably has the collecting electrode 79 of the aggregation member 75 opposed to the through hole 58 of the suction member 70. Thereby, more molten conductors 53a gather on the through-hole 58, the molten conductor 53a can be efficiently sucked into the through-hole 58, and the soluble conductor 53 can be blown out quickly.

[Multiple suction members]
Moreover, the protection element to which the present invention is applied may include a plurality of suction members 54 and 70 as shown in FIGS. 26 (A) and 26 (B), and may be disposed on the front and back surfaces of the soluble conductor 53. In the protection element 80 shown in FIG. 26, for example, the above-described suction member 54 is disposed on the front surface and the back surface of the soluble conductor 53. FIG. 27 is a circuit diagram of the protection element 80. Each suction member 54 disposed on the front and back surfaces of the soluble conductor 53 has one end of the heating element 57 connected to the soluble conductor 53 via the first heating element electrode 59 and the heating element extraction electrode 63. The other end of the heating element 57 is connected to a power source for generating heat from the heating element 57 via the second heating element electrode 60 and the third external connection electrode 61.

When the fusible conductor 53 is melted, the protective element 80 generates heat from the heating elements 57 of the suction members 54 and 54 and sucks the molten conductor 53 into the through holes 58. Accordingly, the protective element 80 is attracted by the plurality of suction members 54 even when the melted conductor 53a is generated in a large amount by increasing the cross-sectional area of the soluble conductor 13 in order to cope with the use of a large current, and is reliably soluble. The conductor 53 can be fused. Further, the protection element 80 can melt the soluble conductor 53 more quickly by sucking the molten conductor 53 a by the plurality of suction members 54.

The protective element 80 can quickly melt the soluble conductor 53 even when a covering structure in which the low melting point metal constituting the inner layer is covered with the high melting point metal is used as the soluble conductor 53. That is, the fusible conductor 53 covered with the high melting point metal takes time to be heated to a temperature at which the outer layer high melting point metal melts even when the heating element 57 generates heat. Here, the protection element 80 includes a plurality of suction members 54 and simultaneously heats the heating elements 57, whereby the refractory metal in the outer layer can be quickly heated to the melting temperature. Therefore, according to the protective element 80, the thickness of the refractory metal layer constituting the outer layer can be increased, and the fast fusing characteristics can be maintained while further increasing the rating.

Further, as shown in FIG. 26, the protection element 80 is preferably connected to the soluble conductor 53 with a pair of suction members 54 and 54 facing each other. As a result, the protection element 80 can simultaneously heat the same portion of the soluble conductor 53 from both sides with the pair of suction members 54 and 54 and suck the molten conductor 53a more quickly. It can be heated and melted.

The protection element 80 uses the suction member 54 in which the heating element 57 is provided on the back surface 55b side of the insulating substrate 55 as a suction member, and the suction member in which the heating element 57 is provided on the front surface 55a side of the insulating substrate 55. A plurality of 70 may be used, or both suction members 54 and 70 may be used in combination.

[Configuration of soluble conductor]
As described above, the soluble conductors 13 and 53 may contain a low melting point metal and a high melting point metal. As the low melting point metal, it is preferable to use solder such as Pb-free solder containing Sn as a main component, and as the high melting point metal, it is preferable to use Ag, Cu or an alloy containing these as main components. At this time, as shown in FIG. 28A, the fusible conductors 13 and 53 may be made of a fusible conductor in which a high melting point metal layer 90 is provided as an inner layer and a low melting point metal layer 91 is provided as an outer layer. Good. In this case, the soluble conductors 13 and 53 may have a structure in which the entire surface of the high melting point metal layer 90 is covered with the low melting point metal layer 91, or may be a structure in which a pair of opposite side surfaces are covered. . The covering structure with the high melting point metal layer 90 and the low melting point metal layer 91 can be formed using a known film forming technique such as plating.

As shown in FIG. 28B, the fusible conductors 13 and 53 may be made of a fusible conductor in which a low melting point metal layer 91 is provided as an inner layer and a high melting point metal layer 90 is provided as an outer layer. . Also in this case, the soluble conductors 13 and 53 may have a structure in which the entire surface of the low-melting-point metal layer 91 is covered with the high-melting-point metal layer 90. Good.

Moreover, the soluble conductors 13 and 53 may have a laminated structure in which a high melting point metal layer 90 and a low melting point metal layer 91 are laminated as shown in FIG.

In this case, as shown in FIG. 29A, the fusible conductor 13 includes the first and second electrodes 11 and 12 and the surface electrode 22, or the first and second external electrodes 51 and 52 and the surface electrode 56. The lower melting point metal layer 91 may be stacked on the upper surface of the lower melting point metal layer 90. On the contrary, the refractory metal layer 90 as the upper layer may be laminated on the upper surface of the low melting point metal layer 91 as the lower layer. Alternatively, the soluble conductors 13 and 53 may be formed as a three-layer structure including an inner layer and an outer layer laminated on the upper and lower surfaces of the inner layer, as shown in FIG. The low melting point metal layer 91 serving as the outer layer may be stacked on the upper and lower surfaces of the layer 90, and the high melting point metal layer 90 serving as the outer layer may be stacked on the upper and lower surfaces of the low melting point metal layer 91 serving as the inner layer.

Further, as shown in FIG. 30, the soluble conductors 13 and 53 may have a multilayer structure of four or more layers in which high melting point metal layers 90 and low melting point metal layers 91 are alternately laminated. In this case, the soluble conductors 13 and 53 may have a structure in which the entire surface or a pair of opposite side surfaces are covered with a metal layer constituting the outermost layer.

Further, the fusible conductors 13 and 53 may be formed by partially laminating the high melting point metal layer 90 in a stripe shape on the surface of the low melting point metal layer 91 constituting the inner layer. FIG. 31 is a plan view of the fusible conductors 13 and 53.

The soluble conductors 13 and 53 shown in FIG. 31A have a plurality of linear refractory metal layers 90 formed in the longitudinal direction on the surface of the low melting point metal layer 91 at predetermined intervals in the width direction. A linear opening 92 is formed along the longitudinal direction, and the low melting point metal layer 91 is exposed from the opening 92. In the fusible conductors 13 and 53, the low melting point metal layer 91 is exposed from the opening 92, thereby increasing the contact area between the molten low melting point metal and the high melting point metal, and further promoting the erosion action of the high melting point metal layer 90. The fusing property can be improved. The opening 92 can be formed, for example, by subjecting the low melting point metal layer 91 to partial plating of a metal constituting the high melting point metal layer 90.

Further, as shown in FIG. 31B, the soluble conductors 13 and 53 are formed with a plurality of linear refractory metal layers 90 in the width direction on the surface of the low melting point metal layer 91 at predetermined intervals in the longitudinal direction. By doing so, a linear opening 92 may be formed along the width direction.

Further, as shown in FIG. 32, the fusible conductors 13 and 53 form a refractory metal layer 90 on the surface of the low melting point metal layer 91 and a circular opening 93 across the entire surface of the refractory metal layer 90. The low melting point metal layer 91 may be exposed from the opening 93. The opening 93 can be formed, for example, by subjecting the low melting point metal layer 91 to partial plating of a metal constituting the high melting point metal layer 90.

The fusible conductors 13 and 53 are exposed to the low melting point metal layer 91 from the opening 93, thereby increasing the contact area between the molten low melting point metal and the high melting point metal and further promoting the erosion action of the high melting point metal. The fusing property can be improved.

In addition, as shown in FIG. 33, the fusible conductors 13 and 53 are formed with a large number of openings 94 in the refractory metal layer 90 which is an inner layer, and the refractory metal layer 90 is low in thickness using a plating technique or the like. A melting point metal layer 91 may be formed and filled in the opening 94. As a result, the fusible conductors 13 and 53 have an increased area where the molten low melting point metal contacts the high melting point metal, so that the low melting point metal can corrode the high melting point metal in a shorter time.

Moreover, it is preferable that the soluble conductors 13 and 53 are formed such that the volume of the low melting point metal layer 91 is larger than the volume of the high melting point metal layer 90. The fusible conductors 13 and 53 are heated by the heat generated by the heating elements 25 and 57, and when the low melting point metal melts, the high melting point metal is eroded and can thereby be melted and blown quickly. Therefore, the soluble conductors 13 and 53 promote this corrosion action by forming the volume of the low melting point metal layer 91 larger than the volume of the high melting point metal layer 90, and promptly the first and second electrodes. 11, 12 or between the first and second external electrodes 51, 52 can be blocked.

Further, as shown in FIG. 34, the fusible conductors 13 and 53 are formed in a substantially rectangular plate shape, and are covered with a high melting point metal constituting the outer layer and are opposed to each other and formed thicker than the main surface portion 96. And a pair of opposing second side edges 98 that are formed to have a thickness lower than that of the first side edge 97 by exposing the low melting point metal constituting the inner layer. You may have.

The side surface of the first side edge portion 97 is covered with the refractory metal layer 90, and is thereby formed thicker than the main surface portion 96 of the soluble conductors 13 and 53. The second side edge 98 has a low melting point metal layer 91 whose outer periphery is surrounded by a high melting point metal layer 90 on the side surface. The second side edge portion 98 is formed to have the same thickness as the main surface portion 96 except for both end portions adjacent to the first side edge portion 97.

In the protective element 1, the fusible conductor 13 has the first side edge 97 mounted along the width direction of the first and second electrodes 11, 12, and the second side edge 98 has the energization direction. Are connected across the first and second electrodes 11 and 12 in the direction of the opposite ends. Similarly, in the protection element 50, the fusible conductor 53 has the first side edge 97 mounted along the width direction of the first and second external electrodes 51 and 52, and the second side edge 98. Are connected across the first and second external electrodes 51 and 52 in the direction of the opposite ends in the energization direction.

Thereby, in the protection elements 1 and 50, the fusible conductors 13 and 53 are quickly blown, and the current path of the external circuit can be cut off.

That is, the second side edge portion 98 is formed to be relatively thinner than the first side edge portion 97. Further, the low melting point metal layer 91 constituting the inner layer is exposed on the side surface of the second side edge portion 98. As a result, the second side edge portion 98 acts to cause the erosion action of the refractory metal layer 90 by the low melting point metal layer 91, and the thickness of the refractory metal layer 90 to be eroded is also the first side edge portion. Since it is formed thinner than 97, it can be rapidly melted with less heat energy as compared with the first side edge 97 formed thick by the refractory metal layer 90. On the other hand, the first side edge 97 is covered with the refractory metal layer 90 to a thickness, and requires a lot of heat energy to blow out as compared with the second side edge 98.

Therefore, the protective elements 1 and 50 are heated immediately between the first electrode 11 and the second electrode 12 where the second side edge 98 is passed, or when the heating elements 25 and 57 generate heat, or The space between the first external electrode 51 and the second external electrode 52 is fused. As a result, the protection elements 1 and 50 block the charge / discharge path between the first and second electrodes 11 and 12 or between the first and second external electrodes 51 and 52, and to the heating elements 25 and 57. Is interrupted, and the heat generation of the heating elements 25 and 57 is stopped.

The soluble conductors 13 and 53 having such a configuration are manufactured by coating a low melting point metal foil such as a solder foil constituting the low melting point metal layer 91 with a metal such as Ag constituting the high melting point metal layer 90. Is done. As a method for coating a low melting point metal layer foil with a high melting point metal, an electrolytic plating method capable of continuously applying a high melting point metal plating to a long low melting point metal foil is advantageous in terms of work efficiency and manufacturing cost. It becomes.

When refractory metal plating is performed by electrolytic plating, the electric field strength is relatively increased at the edge portion of the long low melting point metal foil, that is, the side edge portion, and the refractory metal layer 90 is thickly plated (FIG. 34). reference). As a result, a long conductor ribbon 95 is formed in which the side edge is formed thick by the refractory metal layer. Next, the conductor ribbon 95 is cut into a predetermined length in the width direction (C-C ′ direction in FIG. 34) perpendicular to the longitudinal direction, whereby the soluble conductors 13 and 53 are manufactured. Thus, in the fusible conductors 13 and 53, the side edge of the conductor ribbon 95 becomes the first side edge 97, and the cut surface of the conductor ribbon 95 becomes the second side edge 98. The first side edge portion 97 is covered with a refractory metal, and the second side edge portion 98 has a pair of upper and lower refractory metal layers 90 and a refractory metal layer on an end surface (cut surface of the conductor ribbon 95). A low melting point metal layer 91 surrounded by 90 is exposed to the outside.

1 protection element, 10 first insulating substrate, 10a front surface, 10b back surface, 11 first electrode, 11a first external connection electrode, 11b conductive layer, 12 second electrode, 12a second external connection electrode, 12b Conductive layer, 13 soluble conductor, 13a molten conductor, 14 flux, 15 cover member, 20 suction hole, 21 conductive layer, 22 surface electrode, 23 back electrode, 24 protective element, 25 heating element, 26 insulating layer, 27 3rd External connection electrode, 30 battery pack, 30a positive terminal, 30b negative terminal, 31-34 battery cell, 35 battery stack, 36 detection circuit, 37 current control element, 40 charge / discharge control circuit, 41, 42 current control element, 43 Control unit, 50 protection elements, 51 first external electrode, 52 second external electrode, 53 soluble guide , 53a molten conductor, 54 suction member, 55 insulating member, 55a surface, 55b back surface, 56 surface electrode, 57 heating element, 58 through hole, 59 first heating element electrode, 60 second heating element electrode, 61 third External connection electrode, 62 insulation member, 63 heating element extraction electrode, 63a tab, 64 back electrode, 65 conductive layer, 66 spare solder, 67 island electrode, 70 suction member, 71 protection element, 74 protection element, 75 aggregation member 76, second insulating substrate, 77 heating element, 78 insulating member, 79 collector electrode, 80 protective element, 90 high melting point metal layer, 91 low melting point metal layer, 95 conductor ribbon, 97 first side edge, 98th 2 side edges

Claims (53)

1. A first insulating substrate;
   A fusible conductor mounted on the surface of the first insulating substrate;
   A protection element in which a suction hole for sucking the melted soluble conductor is opened on a surface of the first insulating substrate.
2. The protective element according to claim 1, wherein the suction hole is a through hole or a non-through hole provided in the thickness direction of the first insulating substrate while a conductive layer is formed on an inner surface thereof.
3. The protective element according to claim 2, wherein a surface electrode connected to the conductive layer is formed on a surface of the first insulating substrate.
4. The suction hole is a through hole,
   The protection element according to claim 3, wherein a back surface electrode connected to the conductive layer is formed on the back surface of the first insulating substrate.
5. The protective element according to any one of claims 1 to 4, wherein one or a plurality of the suction holes are formed.
6. The first insulating substrate is formed with first and second electrodes connected to the soluble conductor,
   The protection element according to any one of claims 1 to 4, wherein the first and second electrodes are connected to an external connection electrode formed on a back surface of the first insulating substrate.
7. The protective element according to claim 6, wherein a heating element for melting the soluble conductor is provided on the first insulating substrate.
8. The protection element according to claim 7, wherein the heating element is formed on a surface of the first insulating substrate and is overlapped with the soluble conductor via an insulating member.
9. The protection element according to claim 7, wherein the heating element is formed on a back surface of the first insulating substrate and is superimposed on the soluble conductor.
10. The protective element according to claim 7, wherein the heating element is formed inside the first insulating substrate.
11. A heating element for melting the soluble conductor is provided on the first insulating substrate,
    The protective element according to claim 3 or 4, wherein the heating element is connected to the soluble conductor via the surface electrode.
12. The first insulating substrate is formed with first and second electrodes connected to the soluble conductor,
    The protection element according to claim 11, wherein the first and second electrodes are connected to an external connection electrode formed on a back surface of the first insulating substrate.
13. 13. The protective element according to claim 12, wherein the heating element is formed on a surface of the first insulating substrate and is superimposed on the soluble conductor via an insulating member.
14. 13. The protective element according to claim 12, wherein the heating element is formed on a back surface of the first insulating substrate and is superimposed on the soluble conductor.
15. The protective element according to any one of claims 1 to 4, wherein a flux is applied to a surface of the soluble conductor.
16. The protective element according to any one of claims 2 to 4, wherein the conductive layer contains copper, silver, gold, iron, nickel, palladium, lead, or tin as a main component.
17. The protective element according to any one of claims 1 to 4, wherein the soluble conductor is solder.
18. The protective element according to any one of claims 1 to 4, wherein the soluble conductor contains a low melting point metal and a high melting point metal.
19. The low melting point metal is solder,
    The protective element according to claim 18, wherein the refractory metal is silver, copper, or an alloy containing silver or copper as a main component.
20. 19. The protective element according to claim 18, wherein the soluble conductor has an inner layer made of the refractory metal and an outer layer covered with the low-melting metal.
21. The protective element according to claim 18, wherein the soluble conductor has an inner layer made of the low melting point metal and an outer layer made of the high melting point metal.
22. The protection element according to claim 18, wherein the soluble conductor has a laminated structure in which the low melting point metal and the high melting point metal are laminated.
23. The protective element according to claim 18, wherein the soluble conductor has a multilayer structure of four or more layers in which the low melting point metal and the high melting point metal are alternately laminated.
24. The protective element according to claim 18, wherein the soluble conductor is provided with an opening in the high melting point metal formed on the surface of the low melting point metal constituting the inner layer.
25. The soluble conductor has a high melting point metal layer having a plurality of openings and a low melting point metal layer formed on the high melting point metal layer, and the openings are filled with the low melting point metal. The protective element according to claim 18.
26. The fusible conductor is exposed to a pair of opposing first side edges that are covered with the refractory metal constituting the outer layer and formed thicker than the main surface portion, and the low melting point metal constituting the inner layer is exposed. A pair of opposing second side edges formed in a thickness thinner than the first side edges,
    The first side edge is mounted along the first and second electrodes formed on the surface of the first insulating substrate, and the second side edge is between the first and second electrodes. The protective element according to claim 18, which is connected over the entire area.
27. The protective element according to claim 18, wherein the soluble conductor has a volume of the low melting point metal larger than a volume of the high melting point metal.
28. One or more battery cells;
    A protection element connected to the charge / discharge path of the battery cell and blocking the charge / discharge path;
    The protective element is
    A first insulating substrate;
    A soluble conductor mounted on the surface of the first insulating substrate and serving as the charge / discharge path;
    A battery pack in which a suction hole for sucking the melted soluble conductor is opened on a surface of the first insulating substrate.
29. First and second external electrodes;
    A fusible conductor connected between the first and second external electrodes;
    A suction member connected to the soluble conductor and sucking the melted soluble conductor;
    The suction member is
    A first insulating substrate disposed between the first and second external electrodes;
    A surface electrode formed on the surface of the first insulating substrate and connected to a part of the soluble conductor;
    A heating element provided on the first insulating substrate;
    Provided in the thickness direction of the first insulating substrate, comprising a through-hole continuous with the surface electrode,
    A protective element that blocks a current path between the first external electrode and the second external electrode by melting the soluble conductor.
30. 30. The protective element according to claim 29, wherein the through-hole is formed with a conductive layer continuous with the surface electrode on an inner peripheral surface.
31. A back electrode formed on the back surface of the first insulating substrate;
    The said through-hole is provided in the thickness direction of the said 1st insulated substrate between the said surface electrode and the said back surface electrode, The said conductive layer is continued with the said surface electrode and the said back surface electrode. The protective element as described.
32. 32. The protection element according to claim 31, wherein the heating element is provided on a surface side of the first insulating substrate and is electrically connected to the surface electrode.
33. 32. The protection element according to claim 31, wherein the heating element is provided on a back surface side of the first insulating substrate and is electrically connected to the back electrode.
34. 32. The protection element according to claim 31, wherein the heating element is provided inside the first insulating substrate and is electrically connected to the front surface electrode or the back surface electrode.
35. The protective element according to any one of claims 29 to 34, wherein a part or all of the inside of the through hole is filled with preliminary solder and / or flux.
36. The first insulating substrate according to any one of claims 32 to 34, wherein when the heating element generates heat, one of the front side and the back side where the heating element is provided has a temperature gradient higher than the other. The protective element as described in.
37. 36. The protection element according to claim 35, wherein when the heating element generates heat, the first insulating substrate has a temperature gradient in which one of the front side and the back side where the heating element is provided has a temperature higher than the other.
38. The protective element according to any one of claims 29 to 34, wherein the heating element is disposed on both sides of the through hole.
39. A plurality of the through holes are provided;
    The protection element according to claim 38, wherein the heating element is disposed on both sides of the plurality of through holes.
40. A second insulating substrate;
    A heating element provided on the second insulating substrate for melting the soluble conductor;
    The protective element according to any one of claims 29 to 34, further comprising an aggregating member connected to the fusible conductor and having a collecting electrode for aggregating the molten conductor in which the fusible conductor is melted.
41. 41. The protective element according to claim 40, wherein the aggregating member has the collector electrode connected to a surface of the fusible conductor opposite to the surface to which the suction member is connected.
42. 42. The protective element according to claim 41, wherein the aggregating member has the collecting electrode opposed to the through hole of the suction member.
43. The protection element according to any one of claims 29 to 34, wherein a plurality of the suction members are connected to the soluble conductor.
44. 44. The protective element according to claim 43, wherein the two suction members are connected to the soluble conductor in opposition to each other.
45. 41. The protective element according to claim 40, wherein the soluble conductor has a coating structure in which an inner layer is a low melting point metal and an outer layer is a high melting point metal.
46. 45. The protective element according to claim 43, wherein the soluble conductor has a coating structure in which an inner layer is a low melting point metal and an outer layer is a high melting point metal.
47. One or more battery cells;
    A protection element connected to the charge / discharge path of the battery cell and blocking the charge / discharge path;
    A current control element that detects a voltage value of the battery cell and controls energization to the protection element;
    The protective element is
    First and second external electrodes;
    A fusible conductor connected between the first and second external electrodes;
    A suction member for sucking the melted soluble conductor,
    The suction member is
    A first insulating substrate disposed between the first and second external electrodes;
    A surface electrode formed on the surface of the first insulating substrate and connected to a part of the soluble conductor;
    A heating element provided on the first insulating substrate;
    Provided in the thickness direction of the first insulating substrate, comprising a through-hole continuous with the surface electrode,
    A battery pack that interrupts a current path between the first external electrode and the second external electrode by melting the soluble conductor.
48. A first insulating substrate;
    First and second external electrodes;
    An intermediate electrode provided between the first external electrode and the second external electrode on one surface side of the first insulating substrate;
    A heating element provided on the other surface side of the first insulating substrate;
    One surface of the first insulating substrate is connected to the intermediate electrode and connected to the first and second external electrodes, and the first external electrode and the second electrode are heated by the heating element. A fusible conductor that melts the current path between the external electrodes of
    A heating element extraction electrode provided on the other surface side of the first insulating substrate and electrically connected to one terminal of the heating element;
    A through-hole provided between the intermediate electrode and the heating element extraction electrode in the thickness direction of the first insulating substrate, and provided with a conductive layer continuous with the intermediate electrode and the heating element extraction electrode on the inner surface And a protective element.
49. 49. The protective element according to claim 48, wherein the protective element further comprises a spare solder filled in the through hole.
50. 49. The first insulating substrate is characterized in that when the heating element generates heat, the other surface side of the first insulating substrate has a temperature gradient higher than that of one surface side. The protective element as described.
51. 49. The protective element according to claim 48, wherein the heating element is provided on both sides of the through hole.
52. The through hole is plural,
    52. The protection element according to claim 51, wherein the heating element is disposed on both sides of the plurality of through holes.
53. One or more battery cells;
    A protective element connected to cut off the current flowing through the battery cell;
    A current control element that detects a voltage value of each of the battery cells and controls a current for heating the protection element;
    The protective element is
    A first insulating substrate;
    First and second external electrodes;
    An intermediate electrode provided between the first external electrode and the second external electrode on one surface side of the first insulating substrate;
    A heating element provided on the other surface side of the first insulating substrate;
    One surface of the first insulating substrate is connected to the intermediate electrode and connected to the first and second external electrodes, and the first external electrode and the second electrode are heated by the heating element. A fusible conductor that melts the current path between the external electrodes of
    A heating element extraction electrode provided on the other surface side of the first insulating substrate and electrically connected to one terminal of the heating element;
    A through-hole provided between the intermediate electrode and the heating element extraction electrode in the thickness direction of the first insulating substrate, and provided with a conductive layer continuous with the intermediate electrode and the heating element extraction electrode on the inner surface And having a battery pack.

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