JP6058476B2 - Protective element and mounting body on which protective element is mounted - 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. 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 this type of protection circuit, 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, when a lightning surge or the like is applied and an instantaneous large current flows, the output voltage drops abnormally due to the life of the battery cell, or conversely an excessively abnormal voltage Even when a battery pack is output, battery packs and electronic devices must be protected from accidents such as fire. Accordingly, 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 such a protection circuit for a lithium ion secondary battery or the like, as described in Patent Document 1, a heat generation resistor is provided inside the protection element, and the heat generation resistor can be used on a current path. A structure that melts a molten conductor is generally used.

  As a related technique of the present invention, a protection element 50 is shown in FIGS. The protective element 50 includes an insulating substrate 51, a heating resistor 53 laminated on the insulating substrate 51 and covered with an insulating member 52 such as glass, a pair of electrodes 54 and 54 formed on both ends of the insulating substrate 51, A heating element extraction electrode 55 laminated on the insulating member 51 so as to overlap the heating resistor 53, and both ends are connected to a pair of electrodes 54, 54, respectively, and a central portion is connected to the heating element extraction electrode 55. A molten conductor 56 is provided.

  One end of the heating element extraction electrode 55 is connected to the first heating element electrode 57. The other end of the heating resistor 53 is connected to the second heating element electrode 58. The protective element 50 is coated with a flux 61 on almost the entire surface of the soluble conductor 56 in order to prevent oxidation of the soluble conductor 56. Further, the protection element 50 may place a cover member on the insulating substrate 51 in order to protect the inside.

  In such a protection element 50, a pair of electrodes 54, 54 formed on the surface of the insulating substrate 51 are formed on the back surface of the insulating substrate 51 through conductive through holes 59 formed on the side surface of the insulating substrate 51. The external connection electrode 60 is electrically connected. And the protection element 50 comprises a part of electric current path | route of the said protection circuit by connecting the external connection electrode 60 on the board | substrate of the protection circuit for lithium ion secondary batteries.

JP 2010-003665 A

  By the way, in recent years, HEV (Hybrid Electric Vehicle) and EV (Electric Vehicle) using a battery and a motor are rapidly spreading. As a power source for HEV and EV, a lithium ion secondary battery has been used from the viewpoint of energy density and output characteristics. Moreover, the practical use of the lithium ion secondary battery has been started in an aircraft. High voltage and large current are required for automotive and aircraft applications. For this reason, dedicated cells that can withstand high voltages and large currents have been developed, but in many cases due to manufacturing cost problems, it is necessary to connect multiple battery cells in series and in parallel to use general-purpose cells. Secures sufficient voltage and current.

  In such a large current application as a lithium ion secondary battery, further improvement of the rating is required also in the protective element. That is, when a lithium-ion secondary battery or the like increases in voltage and current, but the protective element mounted on the protection circuit does not have a rating corresponding to the increase in voltage and current, normal use There is a risk that a soluble conductor on the current path may be blown in a state, and a heat generation of the protective element may cause a bad connection or a peripheral element.

  Also in the protective element 50, the internal conduction resistance between the pair of electrodes 54 and 54 connected by the fusible conductor can be sufficiently lowered to meet the rating improvement (for example, less than 1 mΩ).

  However, in the protection element 50 in which the external connection electrode 60 is provided on the back surface of the insulating substrate 51 and the pair of electrodes 54 and 54 are connected to the external connection electrode 60 by the conductive through hole 59, the pair of electrodes 54 and 54 are respectively provided. Even if the conductive through-hole is filled with a conductor, there is a limit to lowering the conductive resistance of the entire protective element.

  Accordingly, an object of the present invention is to provide a protection element capable of improving the rating and a mounting body on which the protection element is mounted in response to an increase in voltage and current of a lithium ion secondary battery or the like. To do.

In order to solve the above-described problems, a protection element according to the present invention includes an insulating substrate, a heating resistor disposed on the insulating substrate, first and second electrodes stacked on the insulating substrate, and A heating element extraction electrode electrically connected to the heating resistor on a current path between the first and second electrodes, and a heating layer extending from the heating element extraction electrode to the first and second electrodes, and heating The soluble conductor that melts the current path between the first electrode and the second electrode, and the surface of the insulating substrate on which the soluble conductor is provided, are formed on the same surface. A first external connection electrode continuous with the first electrode, one or more first surface mounting external connection terminals provided on the first external connection electrode, and a second continuous with the second electrode. an external connection electrode, said second external connection is provided on the electrode 1 or more second And an external connection terminal surface mounting, the first, than the conduction resistance between the second electrode for external connection, between the first surface mount external connection terminal and the second external connection terminals for surface mounting The combined resistance is low.

Further, the mounting body according to the present invention is a mounting body in which the protective element is mounted on the mounting target, and the protective element is laminated on the insulating substrate, the heating resistor disposed on the insulating substrate, and the insulating substrate. First and second electrodes formed, a heating element extraction electrode electrically connected to the heating resistor on a current path between the first and second electrodes, and the heating element extraction electrode from the heating element extraction electrode A fusible conductor that is laminated over the first and second electrodes and that melts the current path between the first electrode and the second electrode by heating, and the first and second electrodes of the insulating substrate; A first external connection electrode that is formed on the same surface as the surface on which the electrode is formed and that is continuous with the first electrode; and a second external connection electrode that is continuous with the second electrode; the first surface-mounted external connection terminal electrodes is connected on said first external connection electrode Via is connected to the mounting object, the second electrode is connected to the second second surface mount external connection the mounting object via the terminal connected on the external connection electrode, the first The combined resistance of the first surface mounting external connection terminal and the second surface mounting external connection terminal is lower than the conduction resistance between the first and second external connection electrodes. .

  According to the present invention, it is possible to easily reduce the conduction resistance ahead of the first and second external connection electrodes, and in combination with the reduction of the internal conduction resistance between the first and second electrodes, The rating can be dramatically improved.

It is sectional drawing which shows the protection element to which this invention was applied. It is a top view which abbreviate | omits a cover member and shows the protection element to which this invention was applied. It is a top view which abbreviate | omits a cover member and shows the other protection element to which this invention was applied. It is a block diagram which shows the structure of the mounting body in which the protection element to which this invention was applied was mounted. It is a figure which shows the circuit structural example of the protection element to which this invention was applied. It is sectional drawing which shows the protection element by which the soluble conductor was blown off. It is sectional drawing which shows the modification of the protection element which incorporated the heat generating body in the insulated substrate. It is sectional drawing which shows the modification of the protection element which formed the heat generating body in the back surface of the insulated substrate. It is a perspective view which shows the modification of the protection element which formed the heat generating body in the surface of the insulated substrate. It is a perspective view which shows the modification of the protection element which formed the heat generating element in the surface of the insulated substrate. It is a figure which shows the protection element which concerns on the related technique of the protection element to which this invention was applied, (A) is a top view, (B) is AA 'sectional drawing.

  Hereinafter, a protection element to which the present invention is applied and a mounted body on which the protection element is mounted 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]
1 and 2 show a protective element 10 to which the present invention is applied. FIG. 1 is a cross-sectional view taken along line AA ′ shown in FIG. As shown in FIGS. 1 and 2, the protective element 10 includes an insulating substrate 11, a heating resistor 14 laminated on the insulating substrate 11 and covered with an insulating member 15, and first elements formed at both ends of the insulating substrate 11. 1, a second electrode 12 (A1), 12 (A2), a heating element extraction electrode 16 laminated on the insulating member 15 so as to overlap the heating resistor 14, and both ends of the first and second electrodes 12 (A1), 12 (A2), and a soluble conductor 13 having a central portion connected to the heating element extraction electrode 16.

  The rectangular insulating substrate 11 is formed by an insulating member such as alumina, glass ceramics, mullite, zirconia, and 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 resistor 14 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 heating resistor 14 is formed by mixing a powdered material of these alloys, compositions or compounds with a resin binder or the like, forming a paste on the insulating substrate 11 using a screen printing technique, and firing the paste. Or the like.

  An insulating member 15 is disposed on the insulating substrate 11 so as to cover the heating resistor 14, and a heating element extraction electrode 16 is disposed so as to face the heating resistor 14 through the insulating member 15. Note that an insulating member 15 may be laminated between the heating resistor 14 and the insulating substrate 11 in order to efficiently transfer the heat of the heating resistor 14 to the soluble conductor.

  One end of the heating element extraction electrode 16 is connected to the heating element electrode 18 (P1). Further, one end of the heating resistor 14 is connected to the heating element electrode 18 (P1), and the other end is connected to the other heating element electrode 18 (P2). A heating element connection terminal 18a is provided on the other heating element electrode 18 (P2). The heating element connection terminal 18a is formed using a metal bump or a metal post, and protrudes upward, like the first and second external connection terminals 22 and 24 described later.

  The soluble conductor 13 is, for example, a single layer structure made of a high melting point metal or a low melting point metal, or a laminated structure having a high melting point metal and a low melting point metal, and preferably has a high melting point metal layer as an inner layer and an outer layer. It is a laminated structure having a low melting point metal layer. In addition, you may make it have a low melting metal layer as an inner layer, and a high melting metal layer as an outer layer. The soluble conductor 13 may be a two-layer laminated structure of an upper layer and a lower layer, and may have a high melting point metal layer as an upper layer and a low melting point metal layer as a lower layer.

  The high melting point metal is preferably a metal mainly composed of Ag, Cu, or any of these, and has a high melting point that does not melt even when board mounting is performed by a reflow furnace. The low melting point metal is preferably a metal mainly composed of 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 is not necessarily higher than the temperature of the reflow furnace, and may be melted at about 200 ° C. By laminating the high melting point metal layer and the low melting point metal layer, even if the reflow temperature exceeds the melting temperature of the low melting point metal and the low melting point metal layer is melted, it is fused as the soluble conductor 13. It does n’t come. The fusible conductor 13 may form a laminated structure by depositing a low melting point metal layer on the high melting point metal layer using a plating technique, or by using another known lamination technique or film forming technique. A laminated structure in which a low melting point metal layer is laminated on a high melting point metal layer can be formed. Further, when the reverse refractory metal layer is used as the outer layer, it can be formed by the same film forming technique. The connection of the fusible conductor 13 to the heating element extraction electrode 16 and the first and second electrodes 12 (A1) and 12 (A2) can be realized by soldering using a low melting point metal layer. it can.

  Further, the protection element 10 is coated with a flux 17 on almost the entire surface of the soluble conductor 13 in order to prevent oxidation of the soluble conductor 13. The protective element 10 has a cover member 19 placed on the insulating substrate 11 to protect the inside. The cover member 19 may be erected on an insulating layer 20 such as glass formed on the first and second electrodes 12 (A1) and 12 (A2).

[Application structure]
As shown in FIGS. 1 and 2, the protective element 10 includes a first electrode 12 (on the surface of the insulating substrate 11 on which the first and second electrodes 12 (A1) and 12 (A2) are formed. The first external connection electrode 21 continuous with A1), the first external connection terminal 22 provided on the first external connection electrode 21, and the second external connection electrode continuous with the second electrode 12 (A2) 23, a second external connection terminal 24 provided on the second external connection electrode 23 is formed.

  The first and second external connection electrodes 21 and 23 are electrodes that connect the protection element 10 and a protection circuit such as a lithium ion secondary battery in which the protection element 10 is incorporated, and the first external connection electrode 21 is the first external connection electrode 21. One electrode 12 (A1) is continuous, and the second external connection electrode 23 is continuous with the second electrode 12 (A2).

  The first and second external connection electrodes 21 and 23 are formed using a general electrode material such as Cu or Ag, and the first and second electrodes 12 (A1) and 12 (A2) of the insulating substrate 11 are formed. It is formed on the same surface as the formation surface. That is, in the protection element 10 shown in FIGS. 1 and 2, the surface on which the soluble conductor 13 is provided becomes the mounting surface. The first and second external connection electrodes 21 and 23 can be formed simultaneously with the first and second electrodes 12 (A1) and 12 (A2).

  A first external connection terminal 22 is provided on the first external connection electrode 21. Similarly, a second external connection terminal 24 is provided on the second external connection electrode 23. These first and second external connection terminals 22 and 24 are connection terminals for mounting on the protection circuit board, and are formed using, for example, metal bumps or metal posts. Further, as shown in FIG. 1, the first and second external connection terminals 22 and 24 have a height protruding from the cover member 19 provided on the insulating substrate 11, and are mounted on the protection element 10. It can be mounted on the circuit board side that is the object.

  Thus, the protective element 10 is provided with the external connection electrode 60 on the back surface of the insulating substrate 51 like the protective element 50 shown as the related art, and the pair of electrodes 54 and the external connection electrode 60 are connected by the conductive through holes 59. External connection terminals 22, 24 are formed on the same surface as the first and second electrodes 12 (A 1), 12 (A 2) via the external connection electrodes 21, 23 instead of being connected (see FIG. 11). ing. The protective element 10 is connected to the first external connection terminal 22 and the second external connection rather than the conduction resistance between the first and second external connection electrodes 21 and 23 connected via the fusible conductor 13. The combined resistance with the terminal 24 is low.

  Thereby, the protection element 10 can improve the rating of the whole element and can cope with a large current. That is, in high current applications such as lithium ion secondary batteries used as power sources such as HEV and EV, further improvement of the rating of the protection element is required. And the internal conduction resistance between the 1st, 2nd external connection electrodes 21 and 23 connected by the soluble conductor 13 can fully be lowered | hung to the extent which can respond to a rating improvement (for example, less than 1 m (ohm)).

  In addition, the protective element 10 includes external connection terminals 22 and 24 on the same surface as the first and second electrodes 12 (A1) and 12 (A2). The external connection terminals 22 and 24 are provided on the external connection electrodes 21 and 23, and a terminal having a high degree of freedom in shape and size and a low conduction resistance can be easily provided. Accordingly, the protection element 10 is configured such that the combined resistance of the first external connection terminal 22 and the second external connection terminal 24 is lower than the internal conduction resistance between the first and second external connection electrodes 21 and 23. Has been.

  Therefore, according to the protection element 10, the conduction resistance ahead of the first and second external connection electrodes 21 and 23, which are high in the configuration of the protection element 50, can be easily reduced. Combined with the reduction in internal conduction resistance between the external connection electrodes 21 and 23, the overall rating of the element can be dramatically improved.

As the first and second external connection terminals 22 and 24, for example, metal bumps or metal posts made of Pb-free solder whose main component is Sn can be used. The shape of the metal bump or the metal post is not limited. The resistance values of the first and second external connection terminals 22 and 24 can be obtained from the material, shape, and size. As an example, a rectangular parallelepiped metal post (Cu core: 0.6 mm × 0.6 mm, cross-sectional area 0.36 mm ² , height 1 mm, specific resistance 17.2 μΩ · mm) was used. In this case, the resistance value of the Cu core part of one terminal is about 0.048 mΩ, and the resistance value obtained by connecting the first and second external connection terminals 22 and 24 in series is less than 0.096 mΩ in consideration of the amount of solder coating. It is low and it turns out that the rating of the protection element 10 whole can be improved.

  The protective element 10 obtains the total resistance value of the entire element from the resistance value between the first and second external connection terminals 22 and 24, and the first and second external connections known as the total resistance value. From the difference from the combined resistance of the terminals 22 and 24, the internal conduction resistance between the first and second external connection electrodes 21 and 23 can be obtained. In addition, the protective element 10 measures the internal conduction resistance between the first and second external connection electrodes 21 and 23, and the first and second external connection terminals 22, 24 combined resistances can be obtained.

  In addition, as shown in FIG. 3, the protection element 10 is widely provided by forming the first and second external connection electrodes 21 and 23 in a rectangular shape or the like, and the first and second external connection terminals 22 and 24 are provided. The conduction resistance may be lowered by providing a plurality. In addition, the protection element 10 is configured to lower the conduction resistance by providing the first and second external connection terminals 22 and 24 having large diameters on the first and second external connection electrodes 21 and 23 that are widely provided. May be.

  The first and second external connection terminals 22 and 24 may be formed by providing low melting point metal layers 22b and 24b on the surfaces of the high melting point metals 22a and 24a serving as cores. As the metal constituting the low melting point metal layers 22b and 24b, solder such as Pb free solder containing Sn as a main component can be preferably used. As the high melting point metals 22a and 24a, Cu or Ag is used as a main component. An alloy to be used can be preferably used.

  By providing the low melting point metal layers 22b and 24b on the surfaces of the high melting point metals 22a and 24a, when the protective element 10 is reflow mounted, the reflow temperature exceeds the melting temperature of the low melting point metal layers 22b and 24b. Even if the metal is melted, it can be prevented from melting as the first and second external connection terminals 22 and 24. The first and second external connection terminals 22 and 24 can be connected to the first and second external connection electrodes 21 and 23 using a low melting point metal constituting the outer layer.

  The first and second external connection terminals 22 and 24 can be formed by forming a low melting point metal on the high melting point metal 22a and 24a by using a plating technique, and other known lamination techniques and films. It can also be formed by using a forming technique.

  The first and second external connection terminals 22 and 24 are formed by a conductive plating layer or a conductive layer formed by applying a conductive paste, in addition to using metal bumps or metal posts. May be.

  In addition, the first and second external connection terminals 22 and 24 are provided in advance on the mounting object side such as a circuit board on which the protection element 10 is mounted. In the mounting body on which the protection element 10 is mounted, The two external connection electrodes 21 and 23 may be connected.

[How to use protection elements]
As shown in FIG. 4, such a protection element 10 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 includes, for example, 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 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 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 switching 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 generates heat by melting the soluble conductor 13 by causing the soluble conductor 13 connected in series via the heating element lead electrode 16 and the connection point of the soluble conductor 13 to generate heat. This is a circuit configuration including the resistor 14. Further, in the protection element 10, for example, the fusible conductor 13 is connected in series on the charge / discharge current path, and the heating resistor 14 is connected to the current control element 37. Of the two electrodes 12 of the protection element 10, the first electrode is connected to A 1 via the first external connection terminal 22, and the second electrode is connected to A 2 via the second external connection terminal 24. Connected to. 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 circuit configuration of the battery pack 30 which is a mounting body on which such a protective element 10 is mounted, the protective element 10 includes first and second external connection electrodes 21 and 23 connected via a fusible conductor 13. The combined resistance of the first external connection terminal 22 and the second external connection terminal 24 is configured to be lower than the conduction resistance between them. Thereby, as for the battery pack 30, the rating is improved as the whole protection element 10, and it can respond to a large current.

  Further, in the battery pack 30, when the heating resistor 14 of the protection element 10 generates heat, the soluble conductor 13 is melted, and is drawn onto the heating element extraction electrode 16 due to its wettability as shown in FIG. 6. . As a result, the protection element 10 can reliably cut off the current path by fusing the fusible conductor 13.

  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.

[Modification 1]
FIG. 7 shows a modified example in the case where the heating resistor 14 having a different arrangement position is used. In the following description, the same components as those of the protective element 10 described above are denoted by the same reference numerals and the details thereof are omitted.

  As shown in FIG. 7, the protection element 70 includes an insulating substrate 11, a heating resistor 14 built in the insulating substrate 11, and electrodes 12 (A 1) and 12 (A 2) formed on both ends of the insulating substrate 11. The heating element extraction electrode 16 laminated on the insulating substrate 11 so as to overlap the heating resistor 14 is connected to the electrodes 12 (A1) and 12 (A2) at both ends, and the central portion is connected to the heating element extraction electrode 16. And a soluble conductor 13 connected thereto.

  The protective element 70 is formed on the surface of the insulating substrate 11 on which the first and second electrodes 12 (A1) and 12 (A2) are formed. The first external connection is continuous with the first electrode 12 (A1). On the electrode 21, the first external connection terminal 22 provided on the first external connection electrode 21, the second external connection electrode 23 continuous with the second electrode 12 (A2), and the second external connection electrode 23 The second external connection terminal 24 provided in the is formed.

  The protective element 70 is provided with a cover member 19 that protects the surface of the insulating substrate 11. Moreover, the flux 17 is apply | coated to the soluble conductor 13 on the surface. The protective element 70 has the same configuration as the protective element 10 described above except that the heating resistor 14 is built in the insulating substrate 11 and the insulating member 15 is not provided.

  In this protective element 70, the heating resistor 14 is built in the insulating substrate 11, whereby the surface 11 a of the insulating substrate 11 is flattened, whereby the heating element lead-out electrode 16 is connected to the electrodes 12 (A 1) and 12 (A 2). ) On the same plane. The protective element 70 can connect the flattened soluble conductor 13 by setting the heating element extraction electrode 16 to the same height as the electrodes 12 (A1) and 12 (A2). Therefore, the protective element 70 can improve the fusing characteristics of the soluble conductor 13.

  In addition, the protective element 70 is made of a material having excellent thermal conductivity as the material of the insulating substrate 11, so that the fusible conductor 13 is equivalent to the case where the insulating member 15 such as a glass layer is interposed by the heating resistor 14. Can be heated.

  Further, the protective element 70 does not require the insulating member 15, and the conductive paste constituting the electrodes 12 (A 1) and 12 (A 2), the heating element extraction electrode 16, and the first and second external connection electrodes 21 and 23. Is applied to the surface 11a of the flat insulating substrate 11 to form the electrodes 12 (A1) and 12 (A2), the heating element extraction electrode 16 and the first and second external connection electrodes 21 and 23 in a lump. Therefore, it is possible to save labor in the manufacturing process. Further, since the protective element 70 has the heat generating resistor 14 built in the insulating substrate 11 and does not overlap the heat generating resistor 14 and the heat generating lead electrode 16 on the surface of 11a, the protective element 70 is low in the thickness direction of the insulating substrate 11. Miniaturization can be achieved by turning back.

[Modification 2]
FIG. 8 shows a modified example in which the heating resistor 14 having a different arrangement position is used.

  As shown in FIG. 8, the protection element 80 is laminated on the insulating substrate 11, the back surface 11 b of the insulating substrate 11, covered with the insulating member 15, and electrodes formed on both ends of the insulating substrate 11. 12 (A1), 12 (A2), a heating element extraction electrode 16 laminated on the insulating substrate 11 so as to overlap the heating resistor 14, and both ends are connected to the electrodes 12 (A1), 12 (A2). And a soluble conductor 13 whose central portion is connected to the heating element extraction electrode 16.

  Further, the protective element 80 is formed on the surface of the insulating substrate 11 on which the first and second electrodes 12 (A1) and 12 (A2) are formed, and is connected to the first external connection continuous with the first electrode 12 (A1). On the electrode 21, the first external connection terminal 22 provided on the first external connection electrode 21, the second external connection electrode 23 continuous with the second electrode 12 (A2), and the second external connection electrode 23 The second external connection terminal 24 provided in the is formed.

  The protective element 80 is provided with a cover member 19 that protects the surface of the insulating substrate 11. Moreover, the flux 17 is apply | coated to the soluble conductor 13 on the surface. The protection element 80 has the same configuration as that of the protection element 10 described above except that the heating resistor 14 is laminated on the back surface 11b of the insulating substrate 11.

  Also in this protection element 80, the heating resistor 14 is laminated on the back surface 11b of the insulating substrate 11, so that the surface 11a of the insulating substrate 11 is flattened, whereby the heating element extraction electrode 16 is connected to the electrode 12 (A1). , 12 (A2) can be formed on the same plane. The protection element 80 can connect the flattened soluble conductor 13 by setting the heating element extraction electrode 16 to the same height as the electrodes 12 (A1) and 12 (A2). Therefore, the protection element 80 can improve the fusing characteristics of the soluble conductor 13.

  In addition, the protective element 80 uses a material having excellent thermal conductivity as the material of the insulating substrate 11, so that the fusible conductor 13 is formed by the heating resistor 14 in the same manner as when laminated on the surface 11 a of the insulating substrate 11. Can be heated.

  Further, the protective element 80 is formed by applying a conductive paste constituting the electrodes 12 (A1) and 12 (A2), the heating element extraction electrode 16 and the first and second external connection electrodes 21 and 23 to the surface 11a of the flat insulating substrate 11. Since the electrodes 12 (A1) and 12 (A2), the heating element extraction electrode 16 and the first and second external connection electrodes 21 and 23 can be formed in a lump by applying to the substrate, labor saving in the manufacturing process Can be achieved.

[Modification 3]
FIG. 9 is a modified example in the case where the heating resistor 14 having a different arrangement position is used.

  As shown in FIG. 9, the protection element 90 includes an insulating substrate 11, a heating resistor 14 stacked on the surface 11a of the insulating substrate 11, and an electrode 12 (A1) formed on the surface 11a of the insulating substrate 11. , 12 (A2) and the heating element lead electrode 16 laminated between the electrodes 12 (A1) and 12 (A2) on the surface 11a of the insulating substrate 11 and electrically connected to the heating resistor 14, A soluble conductor 13 connected to the electrodes 12 (A1) and 12 (A2) and having a central portion connected to the heating element extraction electrode 16 is provided.

  Further, the protective element 90 is formed on the surface of the insulating substrate 11 on which the first and second electrodes 12 (A1) and 12 (A2) are formed, and is connected to the first external connection continuous with the first electrode 12 (A1). The electrode 21, the first external connection terminal 22 (not shown) provided on the first external connection electrode 21, the second external connection electrode 23 continuous with the second electrode 12 (A2), the second A second external connection terminal 24 (not shown) provided on the external connection electrode 23 is formed. In the protection element 90, the heating element extraction electrode 16 is continuously formed from the heating resistor 14.

The protective element 90 is provided with a cover member that protects the surface of the insulating substrate 11 (not shown). The soluble conductor 13 is coated with flux (not shown) on the surface. The protection element 90 has the same configuration as that of the protection element 10 described above except that the heating resistor 14 is laminated on the surface 11 a of the insulating substrate 11. Note that the surface of the heating resistor 14 is covered with an insulating layer (not shown).

  In this protective element 90, the heating resistor 14 is laminated on the surface 11a of the insulating substrate 11, whereby the surface 11a of the insulating substrate 11 is flattened, whereby the heating element lead-out electrode 16 is connected to the electrode 12 (A1), 12 (A2) can be formed on the same plane. The protective element 90 can connect the flattened soluble conductor 13 by setting the heating element extraction electrode 16 to the same height as the electrodes 12 (A1) and 12 (A2). Therefore, the protection element 90 can improve the fusing characteristics of the soluble conductor 13.

  Further, the protective element 90 can efficiently transfer the heat generated to the soluble conductor 13 by laminating the heating resistor 14 and the heating element extraction electrode 16 continuously, and the insulating element 15 The soluble conductor 13 can be heated in the same manner as when the heating resistor 14 and the heating element extraction electrode 16 are overlapped.

  Further, the protective element 90 is formed by applying the conductive paste constituting the electrodes 12 (A 1), 12 (A 2), the first and second external connection electrodes 21, 23, and the heating element extraction electrode 16 to the surface of the flat insulating substrate 11. Since the electrodes 12 (A1) and 12 (A2), the first and second external connection electrodes 21 and 23, and the heating element lead-out electrode 16 can be collectively formed by applying to 11a, the manufacturing process Can be saved. In addition, since the protective element 90 has the heating resistor 14 formed on the surface 11a of the insulating substrate 11 and does not overlap the heating element lead electrode 16, the protective element 90 can be reduced in size by reducing the thickness of the insulating substrate 11 in the thickness direction. Can be planned.

[Modification 4]
In FIG. 10, instead of the configuration in which the heating resistor 14 is formed by applying and baking a conductive paste, a heating element is used, which is adjacent to the electrodes 12 (A1) and 12 (A2). It is a modification of the case.

  As shown in FIG. 10, the protection element 100 is formed adjacent to the insulating substrate 11, the heating element 101 stacked on the surface 11 a of the insulating substrate 11, and the heating element 101 on the surface 11 a of the insulating substrate 11. The electrodes 12 (A1) and 12 (A2) and the first and second external connection electrodes 21 and 23 and the electrodes 12 (A1) and 12 (A2) on the surface 11a of the insulating substrate 11 are stacked to generate heat. A heating element extraction electrode 16 electrically connected to the element 101, and a fusible conductor 13 having both ends connected to the electrodes 12 (A1) and 12 (A2) and a central portion connected to the heating element extraction electrode 16 Prepare. The protection element 100 is replaced with a heating element 101 in place of the heating resistor 14 except that the heating element 101 is mounted on the surface 11a of the insulating substrate 11 and connected to the heating element lead electrode 16 and to the heating element electrode 102. Thus, the configuration is the same as that of the protection element 10 described above. The heating element 101 is mounted on a land portion 103 formed on the surface 11 a of the insulating substrate 11.

  In the protection element 100, the heating element electrode 102 and the above-described current control element 37 are connected, and when an abnormal voltage is detected in any of the battery cells 31 to 34, the heating element 101 is operated and the charge / discharge path of the battery stack 35 is detected. Shut off.

  Also in the protection element 100, the heating element 101 is mounted on the surface 11a of the insulating substrate 11 adjacent to the electrode 12 (A1), so that the surface 11a of the insulating substrate 11 is flattened. The extraction electrode 16 can be formed on the same plane as the electrodes 12 (A1) and 12 (A2). And the protection element 100 can connect the soluble conductor 13 planarized by making the heat generating body extraction electrode 16 the same height as the electrodes 12 (A1) and 12 (A2). Therefore, the protection element 100 can improve the fusing characteristics of the soluble conductor 13.

  In addition, the protection element 100 can efficiently transmit the generated heat to the soluble conductor 13 by mounting the heating element 101 adjacent to the electrodes 12 (A1) and 12 (A2). It is possible to heat the soluble conductor 13 in the same manner as when the heating resistor 14 and the heating element lead electrode 16 are overlapped with each other (see FIG. 1).

  Further, the protective element 100 is formed by applying a conductive paste constituting the electrodes 12 (A 1), 12 (A 2), the first and second external connection electrodes 21, 23 and the heating element extraction electrode 16 to the surface 11 a of the flat insulating substrate 11. Since the electrodes 12 (A1) and 12 (A2), the first and second external connection electrodes 21 and 23, and the heating element extraction electrode 16 can be formed in a lump by applying to the substrate, labor saving in the manufacturing process Can be achieved. Further, since the protection element 100 is not formed by superimposing the heating resistor 14 on the surface 11a of the insulating substrate 11 (see FIG. 1) with the heating element extraction electrode 16, the protection element 100 is low in the thickness direction of the insulating substrate 11. Miniaturization can be achieved by turning back.

  In addition, the protection element 100 can select and mount various elements as the heating element 101, and an element that generates heat at a high temperature suitable for fusing the soluble conductor 13 can be used.

DESCRIPTION OF SYMBOLS 10 Protection element, 11 Insulating board, 12 Electrode, 13 Soluble conductor, 14 Heating resistor, 15 Insulating member, 16 Heating body extraction electrode, 17 Flux, 18 Heating body electrode, 18a Heating body connection terminal, 19 Cover member, 20 Insulating layer, 21 1st external connection electrode, 22 1st external connection terminal, 23 2nd external connection electrode, 24 2nd external connection terminal, 30 battery pack, 31-34 battery cell, 36 detection circuit, 37 Current control element, 40 Charge / discharge control circuit, 41, 42 Current control element, 43 Control unit, 45 Charging device

Claims (11)

An insulating substrate;
A heating resistor disposed on the insulating substrate;
First and second electrodes stacked on the insulating substrate;
A heating element extraction electrode electrically connected to the heating resistor on a current path between the first and second electrodes;
A soluble conductor that is laminated from the heating element extraction electrode to the first and second electrodes, and that melts the current path between the first electrode and the second electrode by heating;
A first external connection electrode formed on the same surface as the surface on which the soluble conductor of the insulating substrate is provided, and continuous with the first electrode, and one or more provided on the first external connection electrode A first surface mounting external connection terminal, a second external connection electrode continuous with the second electrode, and one or a plurality of second surface mounting externals provided on the second external connection electrode With connection terminals,
The combined resistance of the first surface mount external connection terminal and the second surface mount external connection terminal is lower than the conduction resistance between the first and second external connection electrodes. element. The protective element according to claim 1, wherein the external connection terminal for surface mounting is a metal bump or a metal post.   The protective element according to claim 2, wherein the metal bump or the metal post has a low melting point metal layer formed on the surface of the high melting point metal.   4. The protective element according to claim 3, wherein the refractory metal is lead-free solder mainly composed of copper or silver, and the low-melting metal is tin-based. 2. The protective element according to claim 1, wherein the external connection terminal for surface mounting is a metal bump made of lead-free solder mainly composed of tin.   The protective element according to claim 1, wherein the soluble conductor is a laminated structure of a high melting point metal and a low melting point metal.   The protective element according to claim 6, wherein the soluble conductor is a laminated structure in which an inner layer is a high melting point metal and an outer layer is a low melting point metal.   The protective element according to claim 6, wherein the soluble conductor is a laminated structure in which an outer layer is a high melting point metal and an inner layer is a low melting point metal.   The protective element according to claim 6, wherein the soluble conductor is a two-layer laminated structure in which an upper layer is a high melting point metal layer and a lower layer is a low melting point metal layer.   The high-melting-point metal constituting the soluble conductor is Ag or Cu or a metal containing either of them as a main component, and the low-melting-point metal is a metal containing Sn as a main component. The protective element according to any one of the above. In the mounting body in which the protective element is mounted on the mounting target,
The protective element is
An insulating substrate;
A heating resistor disposed on the insulating substrate;
First and second electrodes stacked on the insulating substrate;
A heating element extraction electrode electrically connected to the heating resistor on a current path between the first and second electrodes;
A soluble conductor that is laminated from the heating element extraction electrode to the first and second electrodes, and that melts the current path between the first electrode and the second electrode by heating;
A first external connection electrode that is formed on the same surface as the surface on which the first and second electrodes of the insulating substrate are formed and that is continuous with the first electrode and a second electrode that is continuous with the second electrode. With external connection electrodes,
The first electrode is connected to the mounting object via a first surface mounting external connection terminal connected on the first external connection electrode, and the second electrode is connected to the second external connection. It is connected to the mounting object via the second surface mounting external connection terminal connected on the electrode,
The combined resistance of the first surface mounting external connection terminal and the second surface mounting external connection terminal is lower than the conduction resistance between the first and second external connection electrodes. body.

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