JP6030431B2 - Protective element - Google Patents

Description

  The present invention relates to a protection element that stops charging / discharging of a battery connected on a current path by fusing the current path and suppresses thermal runaway of the battery.

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

  This type of protection element includes an overcharge protection or overdischarge protection operation of the battery pack 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 or the like is applied and an instantaneous large current flows, or the output voltage drops abnormally due to the life of the battery cell. Even when the voltage is output, the battery pack and the electronic device must be protected from accidents such as ignition. Therefore, in order to safely shut off the output of the battery cell in any possible abnormal state, a protection element made of a fuse element having a function of cutting off the current path by an external signal is used. .

  As a protection element of a protection circuit for such a lithium ion secondary battery, a soluble conductor is connected across the first and second electrodes on the current path as described in Patent Document 1. Some of the current paths form a part of the current path, and the fusible conductor on the current path is melted by self-heating due to overcurrent or by a heating element provided inside the protective element. In such a protective element, the molten liquid soluble conductor is collected on the first and second electrodes, thereby interrupting the current path.

JP 2010-003665 A JP 2004-265617 A

  In the protection element using the soluble conductor described above, it is preferable to increase the distance between the first and second electrodes in order to improve the insulation performance when the current path is interrupted. However, along with the downsizing and thinning of electronic devices, further reduction in size and thickness is required as a protective element built in the battery pack, and it is difficult to increase the distance between the first and second electrodes. In addition, with the increase in capacity and output of secondary batteries, there is a demand for higher protection element ratings.

  Here, in order to raise the rating of the protection element, it is necessary to balance the reduction in the conductor resistance of the fusible conductor and the insulation performance when the current path is interrupted. That is, in order to flow a larger amount of current, it is necessary to reduce the conductor resistance, and thus it is necessary to increase the cross-sectional area of the soluble conductor. However, as the cross-sectional area of the fusible conductor increases, the amount of the fusible conductor to be melted increases, and the time required for fusing increases, which may impair safety.

  Further, as the cross-sectional area of the fusible conductor is increased, the allowable amount of the first and second electrodes holding the molten conductor is exceeded, and the overflowed molten conductor causes a short circuit between the first and second electrodes. There is also a fear. As an improvement plan for such a problem, a configuration has also been proposed in which an electrode is also provided on a cover member covering a soluble conductor to increase an allowable amount for holding a molten conductor. However, the heat applied to the fusible conductor is absorbed by the electrode of the cover part, and the wettability of the molten conductor is remarkably lowered, and the allowable amount may be reduced.

  Accordingly, the present invention provides a protective element that improves the rated capacity of a soluble conductor, enables a prompt fusing of the soluble conductor, and increases the allowable amount for holding the molten conductor. Objective.

  In order to solve the above-described problems, a protection element according to the present invention includes an insulating substrate, a first heating element laminated on the insulating substrate, and the insulating substrate so as to cover at least the first heating element. Laminated on the insulating member so as to overlap the first heating element and the first and second electrodes laminated on the insulating substrate on which the insulating member is laminated. A heating element extraction electrode electrically connected to the first heating element on a current path between the first and second electrodes, and from the heating element extraction electrode to the first and second electrodes A soluble conductor that is laminated and that melts the current path between the first electrode and the second electrode by heat, and a cover member that covers the insulating substrate, and is disposed above the soluble conductor. Is provided with a second heating element.

  According to the present invention, the second heating element and the first heating element generate heat. Accordingly, in the present invention, the soluble conductor is heated by the first and second heating resistors. Therefore, according to the present invention, even when the cross-sectional area is increased in order to improve the rating of the fusible conductor on the current path, the fusing can be performed quickly and reliably.

It is a figure which shows the protection element to which this invention was applied, (A) is sectional drawing, (B) shows the top view of the state except the cover member and the flux. It is sectional drawing which shows the protection element to which this invention was applied. It is a figure which shows the whole structure of the battery module incorporating the protection element to which this invention was applied. It is a figure which shows the circuit structure of the protection element to which this invention was applied. It is sectional drawing which shows the state by which the soluble conductor in the conventional protection element was blown out. It is sectional drawing which shows the state by which the soluble conductor in the protection element to which this invention was applied was blown out. It is sectional drawing which shows the modification of the protection element to which this invention was applied. It is a figure which shows the circuit structure of the protection element which concerns on a modification. It is sectional drawing which shows the other modification of the protection element to which this invention was applied. It is a figure which shows the circuit structure of the protection element which concerns on another modification. It is sectional drawing which shows the other modification of the protection element to which this invention was applied. It is sectional drawing which shows the other modification of the protection element to which this invention was applied. It is sectional drawing which shows the other modification of the protection element to which this invention was applied. It is sectional drawing which shows the other modification of the protection element to which this invention was applied. It is sectional drawing which shows the other modification of the protection element to which this invention was applied.

  Hereinafter, a protection element to which the present invention is applied 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. Further, the drawings are schematic, and the ratio of each dimension may be different from the actual one. Specific dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[Configuration of protection element]
As shown in FIGS. 1 and 2, a protection element 10 to which the present invention is applied includes an insulating substrate 11, a first heating resistor 14 laminated on the insulating substrate 11 and covered with an insulating member 15, and an insulating substrate 10. Electrodes 12 (A 1) and 12 (A 2) formed on both ends of the substrate 11, a heating element extraction electrode 16 stacked on the insulating member 15 so as to overlap the first heating resistor 14, and both ends are electrodes 12 (A1) and 12 (A2), each having a soluble conductor 13 having a central portion connected to the heating element extraction electrode 16 and a cover member 19 placed on the insulating substrate 11 and protecting the inside. .

  The insulating substrate 11 is formed in a substantially square shape using an insulating member such as alumina, glass ceramics, mullite, zirconia, and the like. In addition, the insulating substrate 11 may be made of a material used for a printed wiring board such as a glass epoxy board or a phenol board, but it is necessary to pay attention to the temperature when the fuse is blown.

  The first heating resistor 14 has a relatively high resistance value and is a conductive member that generates heat when energized. For example, the first heating resistor 14 is made of W, Mo, Ru, or the like. These alloys, compositions, or compound powders are mixed with a resin binder or the like to form a paste on the insulating substrate 11 by patterning using a screen printing technique and firing.

  An insulating member 15 is disposed so as to cover the first heating resistor 14, and a heating element extraction electrode 16 is disposed so as to face the first heating resistor 14 with the insulating member 15 interposed therebetween. In order to efficiently transfer the heat of the first heating resistor 14 to the fusible conductor, an insulating member 15 may be laminated between the first heating resistor 14 and the insulating substrate 11.

  One end of the heating element lead electrode 16 is connected to the first heating resistor 14 and is connected to the heating element electrode 18 (P1) via the first heating resistor 14. The heating element electrode 18 (P1) is connected to the other heating element electrode 18 (P2) via a conduction electrode 22 and a second heating resistor 25 provided on a cover member 19 described later.

  The fusible conductor 13 is made of a low-melting-point metal that is quickly melted by the heat generated by the first heating resistor 14. For example, Pb-free solder containing Sn as a main component can be suitably used. The soluble conductor 13 may be a laminate of a low melting point metal and a high melting point metal such as Ag, Cu, or an alloy containing these as a main component.

  Even if the reflow temperature exceeds the melting temperature of the low melting point metal layer and the low melting point metal melts when the protective element 5 is reflow mounted by laminating the high melting point metal and the low melting point metal, the soluble conductor 13 does not lead to fusing. Such a soluble conductor 13 may be formed by depositing a low melting point metal on a high melting point metal by using a plating technique, or may be formed by using another known lamination technique or film forming technique. . The fusible conductor 13 can be solder-connected to the heating element extraction electrode 16 and the electrodes 12 (A1) and 12 (A2) using a low melting point metal constituting the outer layer.

  In order to prevent oxidation of the soluble conductor 13 and improve the wettability when the soluble conductor 13 is melted, the flux 17 may be applied to almost the entire surface of the soluble conductor 13.

[Second heating element]
The protective element 10 is formed on the insulating substrate 11 with the electrodes 12 (A1) and 12 (A2), the first heating resistor 14, the insulating member 15, the heating element extraction electrode 16, and the heating element electrode 18 (P1), When 18 (P2) is formed and the fusible conductor 13 is mounted, the inside thereof is protected by being covered with the cover member 19.

  The cover member 19 has a side wall 20 that constitutes a side surface of the protection element 10 and a top surface portion 21 that constitutes an upper surface of the protection element 10, and the side wall 20 is connected to the insulating substrate 11. It becomes a lid that closes the inside of the. The cover member 19 is formed using an insulating member such as a ceramic or a glass epoxy substrate, for example, in the same manner as the insulating substrate 11.

  The side wall 20 has a conductive electrode 22 formed from the base end portion 20 a to the top surface portion 21. For the conductive electrode 22, for example, a known conductive material such as Cu, W, Mo, or Au can be used. Further, the conductive electrode 22 is exposed from the end face of the base end portion 20a. The side wall 20 has a base end 20a connected to the heating element electrodes 18 (P1) and 18 (P2) by an adhesive 23 such as a conductive adhesive or solder paste. Thereby, as for the side wall 20, the conduction electrode 22 is electrically connected to the heat generating body electrodes 18 (P1) and 18 (P2).

  In the top surface portion 21, the second heating resistor 25 is formed between the side walls 20. Similar to the first heating resistor 14, the second heating resistor 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. The second heating resistor 25 is obtained by forming a paste on the top surface portion 21 using a screen printing technique by mixing a powdery body of these alloys, compositions or compounds with a resin binder or the like. And formed by firing. After the second heating resistor 25 is formed on the top surface portion 21, an insulating member constituting the cover member 19 is further laminated to be built in the top surface portion 21. The second heating resistor 25 is formed at a position facing the heating element extraction electrode 16 when the cover member 19 covers the insulating substrate 11.

  The second heating resistor 25 is connected to the conduction electrode 22 formed on the side wall 20 at both ends. The top surface portion 21 generates heat when the second heating resistor 25 is energized through the heating element electrodes 18 (P 1) and 18 (P 2) and the conduction electrode 22. Therefore, the protection element 10 can heat the soluble conductor 13 also from the top surface portion 21 side of the cover member 19.

  Moreover, it is preferable that the top surface part 21 forms the cover part electrode 26 in the inner surface 21a facing the soluble conductor 13. The cover part electrode 26 is formed at a position overlapping the second heating resistor 25. When the first and second heating resistors 14 and 25 generate heat and the fusible conductor 13 is melted, the cover electrode 26 permits the molten conductor to come into contact with and spread out, thereby holding the molten conductor. The capacity can be increased.

  At this time, since the cover element electrode 26 is also heated by the second heating resistor 25 in the protection element 10, the heat of the first heating resistor 14 is not absorbed by the cover electrode 26. Accordingly, the protective element 10 can reliably wet and spread the molten conductor on the cover part electrode 26, and can prevent a short circuit due to the overflowing molten conductor.

[How to use protection elements]
As shown in FIG. 3, the protection element 10 described above is used in a circuit in a battery pack 30 of a lithium ion secondary battery.

  For example, the protection element 10 is used by being incorporated in a battery pack 30 having a battery stack 35 including battery cells 31 to 34 of a total of four lithium ion secondary batteries.

  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 10 to which the present invention that cuts off charging when the battery stack 35 is abnormal, and each battery cell. A detection circuit 36 that detects voltages 31 to 34 and a current control element 37 that controls the operation of the protection element 10 according to the detection result of the detection circuit 36 are provided.

  The battery stack 35 is formed by connecting battery cells 31 to 34 that need to be controlled for protection from overcharge and overdischarge states, and is detachable via the positive electrode terminal 30a and the negative electrode 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 operations 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 10 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 each of the battery cells 31 to 34, detects the voltage value of each of the battery cells 31 to 34, and supplies each voltage value 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 configured 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 protection element 10 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.

  In the battery pack 30 having the above configuration, the protection element 10 to which the present invention is applied has a circuit configuration as shown in FIG. That is, the protective element 10 melts the soluble conductor 13 by generating heat by energizing the soluble conductor 13 connected in series via the heating element extraction electrode 16 and the connection point of the soluble conductor 13. The first heating resistor 14, the first heating resistor 14, the heating electrode 18 (A 1), and the conduction electrode 22. 25 is a circuit configuration. In the protection element 10, for example, the fusible conductor 13 is connected in series on the charge / discharge current path, and the first and second heating resistors 14, 25 are connected to the current control element 37. One of the two electrodes 12 of the protection element 10 is connected to A1, and the other is connected to A2. Further, the heating element extraction electrode 16 and the heating element electrode 18 connected thereto are connected to P1, and the other heating element electrode 18 is connected to P2.

  In the protection element 10 having such a circuit configuration, when a voltage abnormality or the like is detected in any one or a plurality of the battery cells 31 to 34, the current control element 37 causes the second heating resistor 25 and the first heat generation. The resistor 14 generates heat. Thereby, the protection element 10 heats the soluble conductor 13 by the first and second heating resistors 14 and 25. Therefore, according to the protective element 10, even when the cross-sectional area is increased in order to improve the rating of the fusible conductor 13 on the current path, it can be melted quickly and reliably.

  Further, since the protection element 10 is formed with the cover electrode 26 so as to face the heating element extraction electrode 16, as compared with the case where the molten conductor is held only by the heating element extraction electrode 16 shown in FIG. As shown in FIG. 6, the allowable amount for holding the molten conductor can be dramatically improved. Since this cover part electrode 26 is heated by the second heating resistor 25 provided on the top surface part 21, the cover part electrode 26 is sufficiently wetted and spread without impairing the wettability of the soluble conductor 13. Can be increased.

  The protection element of 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 by an electric signal. In addition, the operating condition of the protection element 10 by the current control element 37 is not limited to the case where the voltage of the battery cells 31 to 34 is abnormal. Can be made.

[Modification 1]
Next, modifications of the protection element to which the present invention is applied will be described. Note that, in the protective element described below, the same members as those of the protective element 10 are denoted by the same reference numerals, and the details thereof are omitted.

  7 includes a first heating resistor 14 and a second heating resistor 25 connected in parallel. As shown in FIGS. 7 and 8, in the protection element 50, the first and second heating resistors 14 and 25 are connected to both the heating element electrodes 18 (P 1) and 18 (P 2). In the protection element 50, the heating element electrode 18 connected to the heating element extraction electrode 16 is connected to P1, and the other heating element electrode 18 is connected to P2. Other configurations are the same as those of the protection element 10.

  In the protection element 50 having such a circuit configuration, when a voltage abnormality or the like is detected in any one or more of the battery cells 31 to 34, the current heating element 14 and the second heat generation are generated by the current control element 37. The resistor 25 generates heat. Thereby, the protection element 10 heats the soluble conductor 13 by the first and second heating resistors 14 and 25. Therefore, according to the protective element 10, even when the cross-sectional area is increased in order to improve the rating of the fusible conductor 13 on the current path, it can be melted quickly and reliably. Also in the protection element 50, by providing the cover portion electrode 26 facing the heating element extraction electrode 16 on the top surface portion 21 of the cover member 19, the allowable amount for holding the molten conductor can be increased.

  Further, since the protective element 50 has the first and second heating resistors 14 and 25 connected in parallel, even if one heating resistor breaks due to the influence of static electricity or the like, the other heating resistor The soluble conductor 13 can be blown out.

[Modification 2]
Moreover, you may comprise the protection element to which this invention was applied as follows. The protection element 60 shown in FIG. 9 is formed by connecting the first heating resistor 14 and the second heating resistor 25 to different current paths. As shown in FIGS. 9 and 10, in the protection element 60, the first heating resistor 14 is connected to P <b> 1 through the heating element lead electrode 16 and is connected to P <b> 2 through the heating element electrode 61. . The second heating resistor 25 is connected to a pair of heating element electrodes 62 and 62, and the pair of heating element electrodes 62 and 62 are connected on a current path different from that of the first heating resistor 14. Has been. Other configurations are the same as those of the protection element 10.

  Thus, since the protection element 60 forms the first heating resistor 14 and the second heating resistor 25 on separate current paths, for example, the first heating resistor 14 is connected to the battery cell 31. To 34 are provided, and the second heating resistor 25 is provided on the line to which the IC and the microcomputer are connected, so that the mutual insulation can be improved and the stability of the entire element is improved. be able to.

[Modification 3]
Moreover, you may comprise the protection element to which this invention was applied as follows. The protective element 70 shown in FIG. 11 is not provided with the second heating resistor 25 inside the top surface portion 21 but is provided on the inner surface 21a facing the heating element extraction electrode 16 so as to share the function of the cover portion electrode 26. It is a thing. Other configurations are the same as those of the protection element 50.

  The second heating resistor 25 provided on the inner surface 21a of the top surface portion 21 heats the fusible conductor 13 from the cover member 19 side, and holds the molten conductor in the same manner as the cover portion electrode 26, and allows an allowable amount. Can be increased.

  The protective element 70 is provided with the second heat generating resistor 25 on the inner surface 21a of the top surface portion 21, thereby simplifying the process of forming the second heat generating resistor 25 and reducing the thickness of the top surface portion 21. The thickness can be reduced. The second heat generating resistor 25 may be connected in parallel with the first heat generating resistor 14 as shown in FIG. 11, and as shown in FIG. They may be connected in series.

[Modification 4]
Moreover, you may comprise the protection element to which this invention was applied as follows. The protection element 80 shown in FIG. 12 has a second heating resistor 25 provided on the upper surface 21 b of the top surface portion 21. Other configurations are the same as those of the protection element 50.

  The protective element 80 also simplifies the laminated structure of the top surface 21 and allows the second heating resistor 25 to be formed with a simple configuration. Further, the top surface portion 21 can be thinned to reduce the thickness of the element. Can be reduced. In the protection element 80, the second heating resistor 25 may be connected in parallel with the first heating resistor 14 (FIG. 13), or connected in series with the first heating resistor 14. May be. The protective element 80 is preferably provided with the cover electrode 26 on the inner surface 21 a of the top surface 21.

[Modification 5]
Moreover, you may comprise the protection element to which this invention was applied as follows. The protection element 90 shown in FIG. 13 is electrically connected to the second heating resistor 25, the base substrate 91 on which the second heating resistor 25 is formed, and the second heating resistor 25, and A heating element module 92 having a pair of heating element electrodes 18 (P1) connected to one heating resistor 14 and a conductive electrode 22 connected on 18 (P2). It is mounted on the insulating substrate 11.

  The base substrate 91 is formed using an insulating member such as a ceramic or a glass epoxy substrate, for example, as with the insulating substrate 11. The base substrate 91 incorporates the second heating resistor 25, but may be provided on the inner surface 91a or the upper surface 91b. The conductive electrode 22 is erected on both sides of the base substrate 91 and forms the side wall of the heating element module 92. The conduction electrode 22 is electrically connected to the second heating resistor 25 and connected to the heating element electrodes 18 (P 1) and 18 (P 2) provided on the insulating substrate 11. Two heating resistors 25 are energized and heated.

  In the heating element module 92, the second heating resistor 25 is provided on the base substrate 91 in advance and the pair of conductive electrodes 22 are connected. In the heating element module 92, the base end portion of the conduction electrode 22 is connected to the heating element electrodes 18 (P1) and 18 (P2) formed on the insulating substrate 11. Thereafter, the protection element 90 further provides the cover member 19 so as to cover the heating element module 92.

  As described above, the protective element 90 includes the cover member 19 and the heating element module 92 including the second heating resistor 25. Therefore, since the protection element 90 protects the heating element module 92 by the cover member 19, there is no problem even if the base substrate 91 and the conductive electrode 22 are insufficient in strength. Further, since the protection element 90 covers the heating element module 92 with the cover member 19, it is possible to prevent the heating element module 92 from being influenced from the outside.

  Furthermore, the protection element 90 can be mounted simply by connecting the heating element module 92 that has been modularized in advance to the insulating substrate 11 with a conductive adhesive or the like, and the manufacturing process can be simplified.

[Modification 6]
Moreover, you may comprise the protection element to which this invention was applied as follows. The protection element 100 shown in FIG. 14 is provided integrally with the cover member 19 by connecting the heating element module 92 to the inner surface of the cover member 19. By forming the heating element module 92 integrally with the cover member 19, the protection element 100 can complete the mounting of the heating element module 92 and the attachment of the cover member 19 at the same time, thereby saving labor in the manufacturing process. Further, the protective element 100 can facilitate handling of the heating element module 92 and the cover member 19.

[Modification 7]
Moreover, you may comprise the protection element to which this invention was applied as follows. 15 includes a second heating resistor 111, a base substrate 112 on which the second heating resistor 111 is formed, and a wiring electrode 114 connected to the cover member 120 via a connection wiring 113. The heating element module 115 having Further, the cover member 120 has a conductive layer 123 connected to the pair of heating element electrodes 18 (P1) and 18 (P2) from the side wall 121 to the top surface portion 122.

  In the cover member 120, the conductive layer 123 formed on the top surface portion 122 is connected to the wiring electrode 114 of the heating element module 115 via the connection wiring 113, and the conductive layer 123 is exposed to the end surface of the side wall 121. Are connected to a pair of heating element electrodes 18 (P1) and 18 (P2) connected to the first heating resistor 14 on the insulating substrate 11. Connection between the connection wiring 113 and the wiring electrode 114 and the conductive layer 123 formed on the top surface portion 122 is performed by a conductive adhesive 117 such as solder paste or conductive adhesive paste.

  Also in the protective element 110, the heating element module 114 is connected to the cover member 120 via the connection wiring 113 in advance, so that the mounting of the heating element module 114 and the attachment of the cover member 120 are completed at the same time. Can be achieved. Further, the protection element 110 can facilitate handling of the heating element module 114 and the cover member 120.

  Note that the heating element module 115 preferably forms the module electrode 116 at a position facing the heating element extraction electrode 16. Similar to the cover electrode 26 described above, the module electrode 116 is heated by the second heating resistor 111 to heat the soluble conductor 13 and increase the allowable amount for holding the molten conductor.

1, 50, 60, 70, 80, 90, 100, 110 Protection element, 11 Insulating substrate, 12 electrodes, 13 Soluble conductor, 14 First heating resistor, 15 Insulating member, 16 Heating element extraction electrode, 17 Flux , 18 Heating element electrode, 19, 120 Cover member, 20, 121 Side wall, 21, 122 Top surface part, 22 Conductive electrode, 23 Adhesive, 25 Second heating resistor, 26 Cover part electrode, 30 Battery pack, 31, 32, 33, 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, 45 Charging device, 91 Base substrate, 113 Connection wiring, 123 Conductive layer

Claims (10)

An insulating substrate;
A first heating element laminated on the insulating substrate;
An insulating member laminated on the insulating substrate so as to cover at least the first heating element;
First and second electrodes stacked on the insulating substrate on which the insulating member is stacked;
A heating element laminated on the insulating member so as to overlap the first heating element and electrically connected to the first heating element on a current path between the first and second electrodes An extraction electrode;
A soluble conductor laminated from the heating element extraction electrode to the first and second electrodes, and by heat, fusing a current path between the first electrode and the second electrode;
A cover member covering the insulating substrate,
A protective element provided with a second heating element above the fusible conductor.   The protection element according to claim 1, wherein the second heating element is provided on a top surface portion of the cover member.   The protective element according to claim 2, wherein an electrode is provided on an inner surface of the top surface portion facing the soluble conductor of the cover member.   The protection element according to claim 1, wherein the second heating element is connected in parallel to the first heating element.   The protection element according to claim 1, wherein the second heating element is provided on a current path electrically independent of the current path of the first heating element.   The protection element according to claim 2, wherein the second heating element is provided on an inner surface of the top surface portion facing the soluble conductor of the cover member.   The protection element according to claim 3, wherein the second heating element is provided on an outer surface opposite to the inner surface of the cover member. The second heating element;
A base substrate on which the second heating element is formed;
A heating element module electrically connected to the second heating element and having a conductive electrode connected on a pair of heating element electrodes connected to the first heating element;
The protection element according to claim 1, wherein the heating element module is mounted on the insulating substrate.   The protection element according to claim 8, wherein the heating element module is connected to an inner surface of the top surface portion of the cover member and integrated with the cover member. The heating element module is connected to the inner surface of the top surface portion of the cover member via connection wiring, and is integrated with the cover member.
The protection element according to claim 9, wherein the second heating element is connected to the first and second electrodes through a conductive layer provided on the cover member.

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