JP6483524B2 - Protection element, secondary battery protection circuit, battery pack and battery state management system - Google Patents

Description

  The present invention relates to a protection element applied to a battery device using, for example, a lithium ion secondary battery, a protection circuit for a secondary battery, a battery pack, and a battery state management system.

  As mobile devices such as smartphones, power sources for electric tools, and power sources for electric vehicles, lithium ion secondary batteries using lithium ion doping / undoping (hereinafter referred to as lithium ion batteries as appropriate) are used. A lithium ion battery includes a positive electrode in which a positive electrode active material layer using a lithium composite oxide is formed on a positive electrode current collector, and a carbon-based material such as graphite or a non-graphitizable carbon material that can be doped or dedoped with lithium. The negative electrode active material layer using the material has a negative electrode formed on the negative electrode current collector. The positive electrode and the negative electrode are laminated via a separator and bent or wound to form a battery element. This battery element is housed in, for example, a metal can or a laminate film together with a nonaqueous electrolytic solution obtained by dissolving a lithium salt in an aprotic organic solvent, thereby forming a battery cell. When configuring the power supply of the electronic device described above, one or a plurality of battery cells are connected in series and / or in parallel.

  A protection element is required to prevent overcharge, overdischarge or overcurrent of the lithium ion battery. Conventionally, a protection element mounted on a secondary battery device or the like has not only an overcurrent but also an overvoltage prevention function. This protective element is formed by laminating a soluble conductor composed of a heating element and a low melting point metal body on a substrate, and is formed so that the soluble conductor is blown by an overcurrent, and an overcharge voltage or an excessive discharge voltage is generated. When this occurs, the switching element is turned on by an external signal from the battery control unit, the heating element in the protection element is energized, and the soluble conductor is blown by the heat of the heating element.

  However, in order to confirm whether the protective element actually operated, it was necessary to open the case of the protective element and visually check the inside. The work for that is troublesome, and further, there arises a problem that it is impossible to quickly know that the protection element has been operated.

  A system described in Patent Document 1 has been proposed as a system for detecting that a protection element has been operated and notifying wirelessly. Specifically, a sensor incorporating an IC tag is attached to the window glass, a signal indicating that the window glass is broken is detected by the sensor, and a signal indicating the abnormality is generated. In addition, the wireless terminal device transmits the information to the principal, the mobile phone of the person in charge, and the information device through the public network and the Internet network.

Patent Document 2 describes that when an ECU (Engine Control Unit) receives a transmission signal transmitted by a wireless tire pressure sensor, a wire harness connected to a wheel speed sensor is received as an antenna.

JP 2008-123468 A Japanese Patent No. 3370899

  In the detection method disclosed in Patent Document 1, RFID (Radio Frequency Identification) and a detection sensor are integrated, and when breakage or breakage of a window glass is detected, information on the breakage or breakage is collected wirelessly using an RFID communication function. To the device, and the wireless terminal device receives this information using the indoor antenna. The thing of patent document 1 uses the sensor for detecting breakage of a window glass, and as above-mentioned, it cannot be used as a protection element of the battery which needs to interrupt | block a current path. The thing of patent document 2 also transmits the signal of a wireless tire pressure sensor, and a receiving side (ECU) receives a signal using a cable as an antenna, It is necessary to interrupt | block a current path. It cannot be used as a battery protection element.

  Accordingly, an object of the present invention is to provide a protection element that can be used as a battery current interruption protection element, having an antenna function, a protection circuit for a secondary battery using the protection element, a battery pack having a protection circuit, and a battery state management To provide a system.

The present invention includes a first electrode, a second electrode, a third electrode, and a fourth electrode formed on an insulator;
A first fusible conductor connected to the first electrode and the second electrode;
A conductor having one end on the power feeding side connected to the third electrode;
A second fusible conductor disposed between the other end of the conductor and a fourth electrode grounded at high frequency;
A heating element for heating the first and second soluble conductors,
This is a protective element in which the second fusible conductor is blown before the first fusible conductor so that the conductor has a function as an antenna.

The present invention includes a first electrode, a second electrode, a third electrode, and a fourth electrode formed on an insulator, and a first fusible substance connected to the first electrode and the second electrode. A conductor, a conductor having one end connected to the third electrode, a second fusible conductor disposed between the other end of the conductor and the fourth electrode grounded in high frequency, A heating element that heats the second fusible conductor, and the protective element in which the second fusible conductor is blown earlier than the first fusible conductor so that the conductor has a function as an antenna;
A battery unit including at least one secondary battery, the first soluble conductor of the protection element inserted in the current path,
A secondary battery protection circuit in which, before the first fusible conductor is blown by an excessive current, the second fusible conductor is blown and a signal is transmitted by wireless communication using the conductor as an antenna. is there.

The present invention is a battery pack in which a battery unit including at least one or more secondary batteries and a wiring board on which a protection element and a control circuit are mounted are housed in a case,
The protective element is
A first electrode, a second electrode, a third electrode, and a fourth electrode formed on the insulator; a first soluble conductor connected to the first electrode and the second electrode; A second soluble conductor disposed between a conductor having one end connected to the third electrode, a fourth electrode grounded in high frequency with the other end of the conductor, and a first and second possible conductor A heating element for heating the molten conductor, and the second soluble conductor is melted before the first soluble conductor so that the conductor has a function as an antenna.
A first soluble conductor of the protective element is inserted into the current path of the battery unit;
The battery pack is configured such that before the first fusible conductor is melted by an excessive current, the second fusible conductor is melted and a signal is transmitted by wireless communication using the conductor as an antenna.

The present invention includes a first electrode, a second electrode, a third electrode, and a fourth electrode formed on an insulator, and a first fusible substance connected to the first electrode and the second electrode. A conductor, a conductor having one end connected to the third electrode, a second fusible conductor disposed between the other end of the conductor and the fourth electrode grounded in high frequency, A heating element that heats the second fusible conductor, and the protective element in which the second fusible conductor is blown earlier than the first fusible conductor so that the conductor has a function as an antenna;
A battery unit including at least one secondary battery, the first soluble conductor of the protection element inserted in the current path,
A battery device in which the second fusible conductor is blown and the wireless communication unit transmits a signal using the conductor as an antenna before the first fusible conductor is blown by an excessive current;
A battery state management system comprising: a transmission / reception device that receives a signal from a wireless communication unit of the battery device.

  According to at least one embodiment of the present invention, when the first fusible conductor is blown out due to an abnormality, the second fusible conductor is always blown before the first fusible conductor so that the conductor is an antenna. The signal can be transmitted wirelessly. An antenna necessary for wireless communication can be integrated with the protection element, and the number of parts can be reduced. Furthermore, when the first soluble conductor is not melted, it can be known at a remote location that an abnormal state or a state close to an abnormality has occurred, and the abnormality can be reliably detected. Furthermore, since radio waves are radiated only when the first fusible conductor is melted, power consumption can be reduced compared to a system that always radiates radio waves, and unnecessary radio waves can be reduced. Note that the effects described here are not necessarily limited, and may be any of the effects described in the present specification. Further, the contents of the present invention are not construed as being limited by the exemplified effects in the following description.

It is a block diagram of one Embodiment of the protection circuit of a battery pack. It is a block diagram which shows an example of a structure of a communication module. It is a block diagram of one embodiment of a battery state management system. It is a block diagram used for description of a protection element. It is the top view and sectional drawing of an example of the protection element before an operation | movement. It is the top view and sectional view of a protection element after operation. It is a circuit diagram of a protection element before operation, and a circuit diagram of a protection element after operation. It is sectional drawing before operation | movement of the other example of a protection element, and sectional drawing after operation | movement.

  Embodiments of the present invention will be described below. The embodiments described below are preferred specific examples of the present invention, and various technically preferable limitations are given. However, the scope of the present invention is not limited to the following description. Unless otherwise specified, the present invention is not limited to these embodiments.

<1. Embodiment>
"Battery pack"
An example of a battery pack to which the present invention can be applied will be described with reference to FIG. In the battery pack 1, secondary batteries, for example, battery cells BT1, BT2, BT3, and BT4 of lithium ion secondary batteries (collectively referred to as battery cells BT when these batteries need not be particularly distinguished) are connected in series. Battery part. When a lithium ion battery having a full charge voltage per battery of, for example, 4.2 V is used, the full charge voltage of the battery pack 1 of this embodiment is 16.8 V.

The positive side of the battery part is connected to the terminal t1 of the protection element with antenna 2 as a current interrupting element. A terminal t2 of the protection element with antenna 2 is led out as a + side terminal through switching elements such as FETs (Field Effect Transistors) 3a and 3b. The protection element 2 with an antenna is a protection element provided with a conductor that functions as an antenna, as will be described later. The conductor is connected between the terminals t3 and t4 via a second fusible conductor.

  The minus side of the battery part is led out as a minus side terminal. When charging the battery pack 1, the + side terminal of the battery pack 1 is connected to the + side output terminal of the charger 21, and the − side terminal of the battery pack 1 is connected to the − side output terminal of the charger 21. During discharging, a load is connected to the + side terminal and the − side terminal of the battery pack 1.

  At the time of charging, an authentication process is performed between the battery pack 1 and the charger 21. For example, mutual authentication confirms that the other party is a regular battery pack and a regular charger. When the authentication is established, the charging device performs the same charging operation as that for a normal lithium ion secondary battery. At the time of discharging when a load is connected to the battery pack 1, it is confirmed that the voltage of the battery cell BT of the battery pack 1 is equal to or higher than a predetermined voltage. When the voltage is equal to or higher than the predetermined voltage, discharge from the battery pack 1 is started.

  Each voltage of the battery cell BT is measured by the control unit 4. The control unit 4 has a comparator that compares the measured voltage of each battery cell with a reference voltage, and detects that each voltage of the battery cell BT has reached an excessive voltage that can be determined to be dangerous. Is possible. When it is detected that the voltage of any of the battery cells BT has reached an excessive voltage, the control unit 4 generates a control signal for the switching element, for example, the FET 5 to turn on the FET 5.

  When the FET 5 is turned on, as will be described later, a current is supplied to the heating element provided in the protection element 2 with an antenna, and the first soluble conductor of the protection element 2 with an antenna is fused by the heat of the heating element. The FET 5 functions as a current supply unit for the heating element. The fusing of the first fusible conductor prevents the protection element with antenna 2 from interrupting the charging current, further preventing the charging from proceeding from the overcharged state and causing a dangerous state such as overheating. As will be described later, before the first soluble conductor is melted, the second soluble conductor is melted so that the conductor functions as an antenna. Therefore, the protection element with antenna 2 can notify the outside that an abnormal state has occurred by wireless communication.

  The FETs 3 a and 3 b are controlled by the control unit 6. Although the control unit 6 is simplified, it detects the voltage between the + side terminal and the − side terminal of the battery pack 1 and the charge / discharge current, and controls the battery pack 1 against overcharge, overdischarge, and overcurrent. It is made to protect. The control unit 6 is constituted by a microcomputer, for example. Voltage and current measurements are automatically performed at a predetermined frequency. The protection operation by the control unit 6 is performed with respect to the entire voltage and current of the battery cell BT, whereas the protection operation by the control unit 4 is performed with respect to the voltage of each battery cell BT.

  The FET 3a is connected, for example, for turning on / off the charging current, and the FET 3b, for example, is connected for turning on / off the charging current. Although not shown, a diode having a polarity in a direction of flowing a discharge current is connected in parallel with the charge control FET 3a, and a diode of a polarity in a direction of flowing a charge current is connected in parallel with the discharge control FET 3b. For example, in order to prevent overcharging, the charging control FET 3a is turned off and the charging current is cut off. Even in this case, a discharge current can flow through the diode and the discharge control FET 3b (ON). In order to prevent overdischarge, the discharge control FET 3b is turned off and the discharge current is cut off. Even in this case, the charging current can flow through the diode and the charging control FET 3a (ON).

  As described above, the battery pack is overcharge protected, overdischarge protected, and overcurrent protected by turning on / off the output using the FETs 3a and 3b. However, if the FET 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, or an excessively abnormal voltage is applied. Even when output, battery packs and electronic devices must be protected from accidents such as fire. Therefore, in any abnormal state that can be assumed, a protection element with an antenna (blocking element) 2 having a function of blocking the current path is used to safely block the output of the battery cell.

"communication unit"
A communication unit 11 for performing wireless communication is connected to the battery pack 1 described above. For example, the communication unit 11 is mounted on a control board included in the battery pack 1. The communication unit 11 has a communication module 12. The communication module 12 is connected to the terminal t3 of the protection element with antenna 2 through the matching circuit 13 and the capacitor. A power supply voltage + Vcc is supplied to the communication unit 11. For example, the power supply voltage + Vcc for the communication unit 11 is formed from the battery cells BT of the battery pack 1. The power supply voltage + Vcc may be formed from the output voltage of the charger 21. Furthermore, you may make it use a separate battery power supply, a solar cell, etc. FIG.

  The matching circuit 13 is provided for matching between the communication unit 11 and the antenna. As will be described later, the terminal t4 of the protective element with antenna 2 is grounded in terms of high frequency, and the protective element with antenna 2 forms the conductor constituting the antenna on the insulating substrate when the second soluble conductor is melted. Has been. When the antenna is configured, the communication unit 11 wirelessly transmits a predetermined signal through the antenna.

  An example of the communication module 12 will be described with reference to FIG. The communication module 12 includes a communication unit 15 for wireless communication, a microprocessor (hereinafter referred to as a CPU (Central Processing Unit)) 16 serving as a control unit that controls a communication function and a read / write operation of a storage medium, It has the storage medium 17 which memorize | stores identification information ID, and the storage medium 18 which memorize | stores own ID. The storage media 17 and 18 are constituted by writable nonvolatile memories, for example.

  The CPU 16 includes a RAM (Random Access Memory), a ROM (Read Only Memory), and the like, and comprehensively controls each unit of the communication module 12 by executing a program stored in the ROM. The identification information ID of the other party stored in the storage medium 17 is an ID of a control unit (transmission / reception device) of a battery state management system described later. The identification information ID stored in the storage medium 18 is an ID for identifying the battery pack 1. For example, when a large number of battery cells or battery packs are used like a vehicle-mounted battery device, the battery cell or battery pack in which the antenna-equipped protection element operates can be identified from the ID.

Bidirectional communication is performed between the communication unit 11 and the control unit by a predetermined wireless communication method. As a communication method, for example, IEEE (Institute of Electrical and Electronics Engineers) 802.15.4 can be used. IEEE 802.15.4 is the name of a short-range wireless network standard called PAN (Personal Area Network) or W (Wireless) PAN. The communication rate of this standard is several tens of k to several hundreds of kbps, and the communication distance is several tens of meters to several hundreds of meters. Communication is performed in units of frames.

  As the communication method, other communication methods can be used. That is, a wireless communication standard such as Bluetooth (registered trademark) or Wi-Fi may be used. The Bluetooth (registered trademark) system is applied to multimedia communication and can perform one-to-many connection communication.

"Battery condition management system"
An example of a battery state management system will be described with reference to FIG. In FIG. 3, only one battery pack 1 and communication unit 11 having the above-described configuration is shown, but preferably a plurality of battery packs and communication units are managed.

  The control unit 30 having a function as a base station in the battery state management system includes a communication unit 31, a controller 36, a display device 37, and a storage unit 38. Similar to the communication unit 11 of the battery pack 1 described above, the communication unit 31 includes a communication module 32, a matching circuit 33, and a capacitor 34, and can wirelessly communicate with the communication unit 11 on the battery pack 1 side through the antenna 35. It is said that.

The controller 36 controls the entire control unit 30. The display device 37 is a display such as a liquid crystal or an organic EL (Electroluminescence), and the display device 37 displays a battery state or the like. The storage unit 38 stores a history of the state of the battery pack to be managed. The control unit 30 is not limited to be designed as a new device, but may be realized by adding software to an existing mobile device (smart phone, portable personal computer, etc.).

  When the voltage value of each battery cell BT in the battery unit is in a normal range, one end of the conductor is grounded at high frequency via the switch SW. Therefore, in the protection element 2 with an antenna, as shown to FIG. 4A, an antenna is not comprised and the communication unit 11 cannot communicate. On the other hand, after the voltage of the battery cell BT becomes excessive and the second soluble conductor of the protection element with antenna 2 is melted, the switch SW is turned off and the antenna 19 is configured as shown in FIG. 4B. Accordingly, the communication unit 11 can perform two-way wireless communication with the communication unit 31 of the control unit 30 through the antenna 19.

  An example of a communication method will be described. An inquiry is transmitted from the communication unit 31 of the control unit 30 to the communication unit 11 of the battery pack 1, and the communication unit 31 receives a response from the communication unit 11. The communication unit 11 of the battery pack 1 tries to transmit transmission data including the ID of the control unit 30 and its own ID at a predetermined time interval. Since the antenna is not formed before the second fusible conductor of the protection element with antenna 2 is melted, transmission data cannot be radiated as radio waves. In this case, the communication unit 31 of the control unit 30 cannot receive a response to the inquiry.

  On the other hand, since the antenna is formed after the second soluble conductor of the protection element with antenna 2 is melted, the communication unit 11 can radiate transmission data as radio waves. When the communication unit 31 of the control unit 30 can receive the transmission data from the communication unit 11 of the battery pack 1, it is determined that the second soluble conductor of the protection element 2 with the antenna of the battery pack 1 is blown. can do.

  Since the received data includes the ID of the battery pack 1, the battery pack 1 in which the protection element with antenna 2 operates can be identified from among a plurality of battery packs to be managed. In the control unit 30, for example, the display device 37 displays a message or the like indicating that the second soluble conductor of the protection element with antenna 2 of the battery pack 1 indicated by ID is blown. By looking at the display device 37 of the control unit 30, an administrator or the like can know that the second soluble conductor of the protection element 2 with the antenna has melted, and determines that the battery pack is defective. Can be handled.

Further, when the control unit 30 normally receives the data from the communication unit 11 of the battery pack 1, the control unit 30 returns an acknowledge to the communication unit 11. Therefore, the communication unit 11 can determine whether or not transmission data has been transmitted by determining whether or not an acknowledgment from the control unit 30 has been received. When it is known that the transmission has been completed, information such as the date and time when the second soluble conductor of the protection element with antenna 2 is melted is stored in the nonvolatile memory of the communication module 12, and then the communication unit 11 is turned off. Or the standby state. Further, when the battery pack 1 includes a display element, the display element may be driven to display the operation state of the protection element 2 with the antenna.

"Structure of protective element with antenna"
Hereinafter, an example of the protection element 2 with an antenna will be described. The protection element 2 with an antenna has the same structure as a conventional protection element. FIG. 5A is a plan view of the state before the insulating cover 55 is attached, and FIG. 5B is a plan view of the state covered with the insulating cover 55. FIG. 5C shows a longitudinal cross-sectional view (cross-sectional view taken along the line AA ′ in FIG. 5B) of the protection element 2 with an antenna.

  A first electrode 41, a second electrode 42, a third electrode 51, a fourth electrode 52, and a fifth electrode 43 are formed on a base substrate 40 or an insulating layer 49 that is an insulating substrate. A heating element 48 is provided on the base substrate 40, and a fifth electrode 43 is formed on the heating element 48 via an insulating layer 49.

  Electrode 41, electrode 42, electrode 51, and electrode 52 are formed on base substrate 40, and electrode 43 is formed on insulating layer 49. A first fusible conductor (fuse) 47 is disposed so as to straddle between the electrode 41, the electrode 42, and the electrode 43. The electrode 41 and the soluble conductor 47 are connected by the solder 44, the electrode 42 and the soluble conductor 47 are connected by the solder 45, and the electrode 43 and the soluble conductor 47 are connected by the solder 46.

  A third electrode 51 and a fourth electrode 52 are provided on the base substrate 40. One end side of a conductor 53 formed on the base substrate 40 in an uneven shape is connected to the electrode 51. The other end side of the conductor 53 is connected to the electrode 56. An electrode 57 is provided in the vicinity of the electrode 56 so as to be separated from the electrode 56, and the second soluble conductor 54 is connected between the electrode 56 and the electrode 57. The electrode 57 is connected to the electrode 52 grounded in terms of high frequency. Therefore, when the fusible conductor 54 does not melt, the conductor 53 does not function as an antenna. When the fusible conductor 54 melts, the conductor 53 functions as an antenna.

  The conductor 53 is formed by mixing a powdered solder alloy or solder composition with a resin binder or the like, forming a paste on the base substrate 40 using a screen printing technique, firing the pattern, and the like. Is done. By making the conductor 53 into a concavo-convex pattern, a pattern having a predetermined length can be formed in a limited space. However, such a shape of the conductor 53 is an example, and may be a linear pattern or a plate-like pattern as long as desired characteristics can be obtained as an antenna. For example, when the conductor 53 functions as a monopole antenna, its length is λ / 4. Since the conductor 53 is formed on the dielectric (base substrate 40), the length of the conductor 53 can be shorter than λ / 4. Furthermore, it is good also as a structure which pinches | interposes a conductor with a dielectric material.

  Furthermore, an insulating cover 55 is provided so as to cover the entire surface of the base substrate 40. The insulating cover 55 is formed using an insulating member such as thermoplastic plastic, ceramics, glass epoxy substrate, or the like.

  The first electrode 41 corresponds to the terminal t1 of the protection element with antenna 2 in the block diagram shown in FIG. 1, and the second electrode 42 is the terminal t2 of the protection element with antenna 2 in the block diagram shown in FIG. Corresponding to Further, the third electrode 51 corresponds to the terminal t3 of the protection element 2 with an antenna in the block diagram shown in FIG. 1, and the fourth electrode 52 corresponds to the terminal of the protection element 2 with an antenna in the block diagram shown in FIG. This corresponds to the terminal t4. For example, the fifth electrode 43 is connected to one connection electrode of the heating element 48 through an electrode formed on the insulating layer 49, and the other connection electrode of the heating element 48 is connected to the external connection electrode. Is done. Although not shown, the external connection electrode is provided on the back surface of the base substrate 40, for example.

  The base substrate 40 is formed of an insulating member such as alumina, glass ceramics, mullite, or zirconia. In addition, you may use the material used for printed wiring boards, such as a glass epoxy board | substrate and a phenol board | substrate.

  The heating element 48 is stacked on the surface of the base substrate 40 and is covered with an insulating layer 49. A fifth electrode 43 is formed on the heating element 48 via the insulating layer 49. The heating element 48 may be provided on the back surface of the base substrate 40 as shown in FIG. 8A.

  The heating element 48 is a 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. It is formed by mixing powders of these alloys, compositions, or compounds with a resin binder or the like, forming a paste on the base substrate 40 using a screen printing technique, firing, and the like. . The heating element 48 is connected to the fifth electrode 43 and the external connection electrode.

  As the first soluble conductor 47 and the second soluble conductor 54, a metal that is melted by the heat generated by the heating element 48 can be used. For example, an alloy such as Pb-free solder containing Sn as a main component, Ag, Cu, or an alloy containing these as main components can be used. Here, when heated by the heating element 48, the second fusible conductor 54 is blown out earlier in time than the first fusible conductor 47.

  As described above, when it is detected that the voltage of any battery cell BT of the battery pack 1 has reached an excessive voltage, the FET 5 connected in series with the heating element 48 is turned on by the control signal generated by the control unit 4. It is said. When the FET 5 is turned on, a current flows through the heating element 48 and heat is generated. The soluble conductors 47 and 54 are heated by the heating element 48. Then, it is notified that there is a high possibility that the fusible conductor 54 is blown first and a shut-off operation is performed to the outside by wireless communication. Further, the soluble conductor 47 is blown by the heat of the heating element 48, the current path is cut off, and a protection operation against an abnormal state of the battery pack is performed.

  One method of fusing the fusible conductor 54 before the fusible conductor 47 is to provide a difference between the melting points of the two. That is, the melting point of the soluble conductor 54 is lower than the melting point of the soluble conductor 47. The melting point can be set according to the composition of each soluble conductor. For example, the melting point of the soluble conductor 54 is about 10% lower than the melting point of the soluble conductor 47. The second method is to vary the degree of heat conduction by the heating element 48 for each soluble conductor. In other words, by setting different heat conduction paths between the respective soluble conductors and the heating element 48, the relationship after the fusing is set. The distance between each soluble conductor and the heating element 48 is set in a two-dimensional plane or a three-dimensional space. Alternatively, the thermal conductivity of an object existing in the heat transfer path is set. In the third method, the shape of each fusible conductor is made different so as to set the relationship after the fusing. Furthermore, two or more of these first, second, and third methods may be combined.

  The protection element with antenna 2 after the protection element with antenna 2 operates, that is, after the fusible conductors 47 and 54 have melted, will be described with reference to FIG. FIG. 6C shows a cross-sectional view taken along line B-B ′ in the plan view of the protective element with antenna 2 shown in FIG. 6B. As shown in FIG. 6A, a melted soluble conductor (hereinafter, appropriately referred to as a molten conductor) 61 is formed on the first electrode 41, a molten conductor 62 is formed on the second electrode 42, and a molten conductor 63 is formed. Is formed on the fifth electrode 43. By melting the fusible conductor 54, the molten conductor 64 is formed on the electrode 56, and the molten conductor 65 is formed on the electrode 57.

  As shown in FIG. 6A, when the second soluble conductor 54 is melted, the connection between the conductor 53 and the electrode 52 is broken, and the conductor 53 functions as an antenna. Therefore, the antenna (conductor 53) can radiate a high-frequency signal into the space as a radio wave. The communication unit 11 is mounted on the wiring board, and the antenna terminal (feeding terminal) of the communication unit 11 is electrically connected to the electrode 51.

"Circuit configuration of protection element with antenna"
If the protection element 2 with an antenna is represented by a circuit configuration, it is as shown in FIG. Terminals corresponding to the first electrode 41 and the second electrode 42 are represented by t1 and t2, respectively, and terminals corresponding to the third electrode 51 and the fourth electrode 52 are represented by t3 and t4, respectively. Further, the first fusible conductor 47 is represented by a fuse F47, and the second fusible conductor 54 is represented by a fuse F54. Further, an antenna constituted by the conductor 53 is represented by ANT53, and the heating element 48 is represented by a resistor R48.

  FIG. 7A shows a circuit configuration before the protection element with antenna 2 operates (normal state). A current path between the positive electrode side of the battery part of the battery pack 1 (see FIG. 1) and the FET 3a is a path between the terminals t1 and t2. The fuse F47 and the fuse F54 are not blown, and no current flows through the resistor R48.

  The third electrode 43 is connected to one end of the resistor R48 corresponding to the heating element 48 via the lead electrode, and the other end of the resistor R48 is grounded via the FET 5. As described above, the FET 5 is turned on by a control signal generated by the control unit 4 when it is detected that the voltage of any battery cell BT has reached an excessive voltage. When the FET 5 is turned on, a current flows through the heating element 48 and heat is generated. This heat blows the fuse F54. The circuit configuration in this state is as shown in FIG. 7B. In this state, the antenna ANT53 can operate, and the transmission signal from the communication unit 11 is radiated as a radio wave.

  Further, when the heating element 48 is heated, the fuse F47 (first fusible conductor 47) is blown, and the current path is cut off as shown in FIG. Even at this stage, the antenna ANT53 has an antenna function.

  Note that the heating element 48 may be provided on the back surface of the base substrate 40 in addition to the surface of the base substrate 40 as shown in FIGS. 8A and 8B. 8A is a cross-sectional view before the fusible conductor 47 is blown out, as in FIG. 5C, and FIG. 8B is a cross-sectional view after the fusible conductor 47 is blown out, as in FIG. 6C.

  According to one embodiment of the present invention, it is possible to realize the protection element with antenna 2 in which the antenna is configured by abnormality of the battery unit. Further, it is possible to notify the external transmission / reception device (control unit 30) by wireless communication that the second soluble conductor of the protection element with antenna 2 has melted. When the first soluble conductor is blown, the second soluble conductor is always blown before that. Thereby, the fusing of the first soluble conductor can be communicated to the outside in advance. Therefore, it is not necessary to open the cover and visually check that the fusible conductor 47 is blown in the protection element 2 with the antenna. Furthermore, the antenna necessary for wireless communication can be integrated with the protection element, and the number of parts can be reduced. Furthermore, since the radio wave is radiated only when the protection element with the antenna is operated, the power consumption can be reduced as compared with the method of always radiating the radio wave, and unnecessary radio waves can be radiated.

<2. Modification>
Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications based on the technical idea of the present invention are possible. For example, the configurations, methods, processes, shapes, materials, numerical values, and the like given in the above-described embodiments are merely examples, and different configurations, methods, processes, shapes, materials, numerical values, and the like are used as necessary. Also good.

BT1 to BT4 Battery cell 1 Battery pack 2 Protection element with antenna 4, 6 Control unit 11, 31 Communication unit 30 Control unit 36 Controller 40 Base substrate 41, 42, 43, 51, 52, 56, 57 Electrode 47 First possible Molten conductor 48 Heating element 54 Second soluble conductor

Claims (8)

A first electrode, a second electrode, a third electrode and a fourth electrode formed on the insulator;
A first fusible conductor connected to the first electrode and the second electrode;
A conductor having one end on the power feeding side connected to the third electrode;
A second fusible conductor disposed between the other end of the conductor and the fourth electrode grounded at high frequency;
A heating element for heating the first and second soluble conductors,
A protective element in which the second fusible conductor is blown before the first fusible conductor so that the conductor has a function as an antenna.   The protection element according to claim 1, wherein the melting point of the second soluble conductor is lower than the melting point of the first soluble conductor. A fifth electrode is provided on the insulator;
The first soluble conductor and one terminal of the heating element are connected via the fifth electrode, and the other terminal of the heating element is connected to a switch element,
The protection element according to claim 1 or 2, wherein the heating element generates heat when the switch element is turned on by a control signal.   The protection element according to claim 1, wherein the conductor is formed as a printed pattern on an insulator. A first electrode, a second electrode, a third electrode, and a fourth electrode formed on the insulator; a first soluble conductor connected to the first electrode and the second electrode; A second fusible conductor disposed between a conductor having one end connected to the third electrode and the fourth electrode grounded in high frequency with the other end of the conductor; A heating element that heats the first and second fusible conductors, and the second fusible conductor is blown earlier than the first fusible conductor so that the conductor has a function as an antenna. Protective element,
A battery unit including at least one secondary battery, wherein the first soluble conductor of the protection element is inserted in a current path;
Before the first fusible conductor is blown by an excessive current, the second fusible conductor is blown and a signal is transmitted by wireless communication using the conductor as an antenna. Protection circuit. A battery pack in which a battery unit including at least one secondary battery and a wiring board on which a protection element and a control circuit are mounted are housed in a case,
The protective element is
A first electrode, a second electrode, a third electrode, and a fourth electrode formed on the insulator; a first soluble conductor connected to the first electrode and the second electrode; A second fusible conductor disposed between a conductor having one end connected to the third electrode and the fourth electrode grounded in high frequency with the other end of the conductor; A heating element that heats the first and second fusible conductors, and the second fusible conductor is blown earlier than the first fusible conductor so that the conductor has a function as an antenna. And
The first soluble conductor of the protection element is inserted into the current path of the battery unit;
A battery pack in which, before the first soluble conductor is melted by an excessive current, the second soluble conductor is melted and a signal is transmitted by wireless communication using the conductor as an antenna. A first electrode, a second electrode, a third electrode, and a fourth electrode formed on the insulator; a first soluble conductor connected to the first electrode and the second electrode; A second fusible conductor disposed between a conductor having one end connected to the third electrode and the fourth electrode grounded in high frequency with the other end of the conductor; A heating element that heats the first and second fusible conductors, and the second fusible conductor is blown earlier than the first fusible conductor so that the conductor has a function as an antenna. Protective element,
A battery unit including at least one secondary battery, wherein the first soluble conductor of the protection element is inserted in a current path;
A battery device in which, before the first fusible conductor is blown by an excessive current, the second fusible conductor is blown and the radio communication unit transmits a signal using the conductor as an antenna; ,
A battery state management system comprising: a transmission / reception device that receives a signal from the wireless communication unit of the battery device.   The battery state management system according to claim 7, wherein data transmitted by the wireless communication unit of the battery device includes an ID that identifies the battery device.

Images