JP2015162941A - Power storage system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem of increase in the number of wiring lines in connecting respective voltage detection circuit and current cut-off circuit with a power storage apparatus.SOLUTION: A voltage detection circuit detects, by using a first voltage detection line, a voltage value of each power storage element used for controlling charge/discharge of a power storage apparatus. A current cut-off circuit includes a second switch element for cutting off energization to an exciting coil when a voltage value of a power storage element detected using a second voltage detection line is higher than a threshold. The voltage detection circuit and the current cut-off circuit are mounted on the same board; and the first voltage detection line and the second voltage detection line branch on the board. The board and the power storage apparatus can be connected with each other by using a voltage detection line obtained by integrating the first voltage detection line and the second voltage detection line.

Description

  The present invention relates to a technology for cutting off a connection between a power storage device and a load.

  In Patent Document 1, a protection IC for determining that each cell constituting the assembled battery is in an overcharge state is provided, and an output signal of the protection IC is input to a microcomputer. The protection IC monitors the voltage value of each cell, and determines that it is overcharged when this voltage value exceeds a predetermined voltage value. At this time, a signal (high signal) indicating an overvoltage is output from the protection IC.

JP 2009-178014 A

  When controlling charging / discharging of an assembled battery, it is necessary to detect the voltage value of each cell. For this reason, in Patent Document 1, it is necessary to provide a voltage detection circuit for detecting the voltage value of each cell in addition to the protection IC described above. In this case, each of the protection IC and the voltage detection circuit must be connected to each cell, which increases the number of wirings.

  The power storage system of the present invention includes a power storage device, a relay, a controller, a voltage detection circuit, and a current interruption circuit. The power storage device includes a plurality of power storage elements that are electrically connected in series. The relay connects the power storage device to the load when the excitation coil is energized, and disconnects the connection between the power storage device and the load when the excitation coil is not energized. The controller controls the first switch element that switches between ON that allows energization of the exciting coil and OFF that interrupts energization of the exciting coil.

  A voltage detection circuit detects the voltage value of each electrical storage element used in order to control charging / discharging of an electrical storage apparatus using a 1st voltage detection line. The current interrupt circuit includes a second switch element that interrupts energization of the exciting coil when the voltage value of the power storage element detected using the second voltage detection line is higher than a threshold value. The voltage detection circuit and the current interruption circuit are mounted on the same substrate, and the first voltage detection line and the second voltage detection line are branched on the substrate.

  According to the present invention, the first voltage detection line and the second voltage detection line can be branched on the substrate by mounting the voltage detection circuit and the current cutoff circuit on the same substrate. Thus, the substrate including the voltage detection circuit and the current cutoff circuit can be connected to the power storage device (each storage element) using the voltage detection line in which the first voltage detection line and the second voltage detection line are shared. it can.

It is a figure which shows the structure of the battery system in Example 1. FIG. In Example 1, it is a figure which shows the structure of a current interruption circuit. FIG. 4 is a diagram showing a partial configuration of a battery system in Example 2.

  Examples of the present invention will be described below.

  FIG. 1 is a diagram showing a configuration of a battery system of the present embodiment (corresponding to the power storage system of the present invention).

  The assembled battery (corresponding to the power storage device of the present invention) 10 has a plurality of unit cells (corresponding to the power storage element of the present invention) 11 electrically connected in series. As the cell 11, a secondary battery or an electric double layer capacitor can be used. The assembled battery 10 is connected to the load 20 via the positive electrode line PL and the negative electrode line NL. The load 20 operates by receiving the discharge power of the assembled battery 10 or generates power for charging the assembled battery 10. When the battery system of this embodiment is mounted on a vehicle, a motor / generator can be used as the load 20.

  A system main relay SMR-B is provided in the positive electrode line PL, and a system main relay SMR-G is provided in the negative electrode line NL. System main relays SMR-B and SMR-G are switched between ON and OFF by receiving a control signal from ECU (Electric Control Unit) 70. Specifically, the ECU 70 can switch the system main relays SMR-B and SMR-G between on and off by switching the first switch element (transistor) 80 between on and off.

  A monitoring IC (Integrated Circuit) 40, a photocoupler 50, and a current interruption circuit 60 are mounted on the substrate 30. The monitoring IC (corresponding to the voltage detection circuit of the present invention) 40 is connected to each unit cell 11 of the assembled battery 10 via the first voltage detection line L1, and detects the voltage value of each unit cell 11. . The monitoring IC 40 can be configured using a comparator or the like as is well known. By using the comparator, the potential difference between the positive electrode terminal and the negative electrode terminal in the unit cell 11, in other words, the voltage value of the unit cell 11 can be detected. A part of the first voltage detection line L1 is mounted on the substrate 30.

  In the present embodiment, the monitoring IC 40 detects the voltage value of the single battery 11, but is not limited to this. For example, the monitoring IC 40 can detect the voltage value of a battery block (corresponding to the power storage element of the present invention) including the plurality of single cells 11. The battery block can be constituted by a plurality of unit cells 11 electrically connected in series. The assembled battery 10 can be configured by electrically connecting a plurality of battery blocks in series.

  An output signal of the monitoring IC 40 (a signal indicating the voltage value of each unit cell 11) is input to the ECU 70 via the photocoupler 50. By using the photocoupler 50, the circuit located on the input side of the photocoupler 50 and the circuit located on the output side of the photocoupler 50 can be insulated. The ECU 70 can acquire the voltage value of each unit cell 11 based on the output signal of the monitoring IC 40. And the microcomputer 71 in ECU70 can control charging / discharging of the assembled battery 10 based on the voltage value of each cell 11. FIG.

  The current interruption circuit 60 is connected to each unit cell 11 via the voltage detection line L2, and can detect the voltage value of each unit cell 11. As described above, when the monitoring IC 40 detects the voltage value of each battery block, the current interrupt circuit 60 detects the voltage value of each battery block. Here, the first voltage detection line L1 and the second voltage detection line L2 are partially shared. A first voltage detection line L1 and a second voltage detection line L2 are branched on the substrate 30, and a voltage detection line in which the first voltage detection line L1 and the second voltage detection line L2 are shared outside the substrate 30. Is arranged.

  The current cut-off circuit 60 cuts off the connection between the assembled battery 10 and the load 20 when the unit cell 11 is in an overcharged state. Specifically, when the cell 11 is in an overcharged state, the current interrupt circuit 60 switches the system main relays SMR-B and SMR-G from on to off. Here, since it is sufficient that the connection between the assembled battery 10 and the load 20 can be cut off, the current cut-off circuit 60 may switch at least one of the system main relays SMR-B and SMR-G from on to off.

  Next, the configuration of the current interrupt circuit 60 will be described with reference to FIG.

  The current interruption circuit 60 has a resistor R2, and the resistor R2 is provided in each voltage detection line L2. The resistor R <b> 2 is used to prevent an overvoltage from the assembled battery 10 (unit cell 11) from being applied to the current interrupt circuit 60. That is, when an overvoltage is to be applied to the current interrupt circuit 60, the resistor R2 is melted to prevent the overvoltage from being applied to the current interrupt circuit 60.

  The current interrupt circuit 60 includes a plurality of Zener diodes D. Each zener diode D is electrically connected in parallel with each unit cell 11 via a voltage detection line L2. Here, the cathode of the Zener diode D is connected to the positive terminal of the single battery 11, and the anode of the Zener diode D is connected to the negative terminal of the single battery 11. The plurality of Zener diodes D are electrically connected in series.

  The Zener diode D is used for suppressing application of an overvoltage from the assembled battery 10 (unit cell 11) to the current interrupt circuit 60. That is, when an overvoltage is to be applied to the current interrupt circuit 60, the Zener diode D becomes conductive, so that a current can flow from the cathode to the anode. Thereby, it can suppress that an overvoltage is applied to the IC (Integrated Circuit) 61 side mentioned later.

  When the Zener diode D becomes conductive, the resistor R2 can be blown by passing a current through the resistor R2. That is, when an overvoltage is to be applied from the assembled battery 10 to the IC 61, the connection between the assembled battery 10 and the IC 61 can be interrupted by fusing the resistor R <b> 2. Thereby, the IC 61 can be protected. Note that the Zener diode D can be omitted if the application of overvoltage to the current interrupt circuit 60 can be excluded.

  The current interrupt circuit 60 has a capacitor C. One end of the capacitor C is connected to the voltage detection line L2, and the other end of the capacitor C is grounded. The capacitor C is provided for each voltage detection line L2, and is used to reduce noise in the voltage detection line L2. A connection point of the capacitor C with respect to the voltage detection line L2 is located between an IC 61 described later and a connection point of the Zener diode D with respect to the voltage detection line L2. If the influence of noise can be ignored, the capacitor C can be omitted.

  The current interruption circuit 60 has an IC 61. The IC 61 receives a start signal or a stop signal from the ECU 70. The activation signal is a signal that allows the power from the power supply to be supplied to the IC 61, and the IC 61 can be operated by the activation signal. The stop signal is a signal for stopping the power supply from the power source to the IC 61, and the operation of the IC 61 can be stopped by the stop signal.

  The IC 61 has a comparator CMP. The voltage detection line L2 connected to the positive terminal of each unit cell 11 is connected to the negative input terminal of the comparator CMP. Further, the voltage detection line L2 connected to the negative terminal of each unit cell 11 is connected to the positive input terminal of the comparator CMP.

  Here, as shown in FIG. 2, the voltage detection line L <b> 2 connected to the positive terminal of one unit cell 11 and the negative terminal of the other unit cell 11 is branched. The branched voltage detection line L2 is connected to a positive input terminal of one comparator CMP and a negative input terminal of the other comparator CMP.

  The comparator CMP outputs the potential difference between the positive electrode terminal and the negative electrode terminal in the unit cell 11, in other words, the voltage value of the unit cell 11. The IC 61 has an OR circuit 62 connected to the comparator CMP, and an output signal from the comparator CMP is input to the OR circuit 62. The OR circuit 62 is connected to a plurality of comparators CMP, and when the output signal of one of the comparators CMP is input to the OR circuit 62, the OR circuit 62 generates an output signal.

  In the present embodiment, the plurality of comparators CMP operate at different timings. That is, output signals from the plurality of comparators CMP are input to the OR circuit 62 at different timings. For this reason, every time the voltage value of each cell 11 is detected, the OR circuit 62 outputs a signal corresponding to this voltage value.

  The IC 61 has an alarm confirmation circuit 63 connected to the OR circuit 62, and an output signal of the OR circuit 62 is input to the alarm confirmation circuit 63. The alarm confirmation circuit 63 determines the overcharged state of the unit cell 11 and outputs an alarm signal when the unit cell 11 is in the overcharged state. The alarm signal is a signal indicating that the unit cell 11 is in an overcharged state.

  The alarm confirmation circuit 63 can be configured by a comparator. The output signal of the OR circuit 62 (the voltage value Vb of the unit cell 11) is input to the negative input terminal of the alarm determination circuit (comparator) 63. The threshold value (voltage value) V_th is input to the positive input terminal of the alarm determination circuit (comparator) 63.

  The threshold value (voltage value) V_th is a voltage value for determining the overcharge state of the unit cell 11 and can be appropriately set in consideration of the charge / discharge characteristics of the unit cell 11 and the like. For example, the threshold value (voltage value) V_th is set to a voltage value when the cell 11 is actually overcharged, or a value lower than the voltage value when the cell 11 is actually overcharged. Can be set.

  When the output signal of the OR circuit 62 (the voltage value Vb of the single battery 11) is higher than the threshold value (voltage value) V_th, the output signal (alarm signal) of the alarm determination circuit (comparator) 63 is generated. On the other hand, when the output signal of the OR circuit 62 (the voltage value Vb of the single cell 11) is lower than the threshold value (voltage value) V_th, the output signal (alarm signal) of the alarm determination circuit (comparator) 63 is not generated.

  The IC 61 has an alarm latch circuit 64 connected to the alarm confirmation circuit 63, and an output signal (alarm signal) of the alarm confirmation circuit 63 is input to the alarm latch circuit 64. The alarm latch circuit 64 holds the input signal from the alarm confirmation circuit 63 and outputs a latch signal (corresponding to an alarm signal).

  The IC 61 (alarm latch circuit 64) is connected to the photocoupler 65. The photocoupler 65 is used as a switch element, and is switched from off to on by receiving a latch signal from the alarm latch circuit 64. Since the photocoupler 65 is an insulating element, the circuit positioned on the input side of the photocoupler 65 (high voltage circuit) and the circuit positioned on the output side of the photocoupler 65 (low voltage circuit) are insulated. Can do. In other words, the photocoupler 65 can convert a high voltage signal as an input signal into a low voltage signal as an output signal.

  The photocoupler 65 is connected to the second switch element (transistor) 66. When the photocoupler 65 is switched from off to on, the output signal of the photocoupler 65 is input to the second switch element 66. The second switch element 66 receives the output signal of the photocoupler 65 and switches from on to off. Here, when the output signal of the photocoupler 65 is not input to the second switch element 66, the second switch element 66 is turned on.

  One end of the second switch element 66 is connected to the power supply 100, and the other end of the second switch element 66 is connected to the excitation coil 91 of the system main relays SMR-B and SMR-G. When the second switch element 66 is on, a current can flow from the power source 100 to the exciting coil 91. The system main relays SMR-B and SMR-G have a movable contact 92 and a fixed contact 93. When the exciting coil 91 is in an energized state, the movable contact 92 contacts the fixed contact 93. As a result, the system main relays SMR-B and SMR-G are turned on.

  Here, the first switch element 80 is also connected to the exciting coil 91. For this reason, when the 1st switch element 80 and the 2nd switch element 66 are ON, an electric current can be sent through the exciting coil 91 from the power supply 100. FIG. When at least one of the first switch element 80 and the second switch element 66 is off, no current flows from the power supply 100 to the exciting coil 91. Therefore, even if the ECU 70 outputs a control signal for turning on the first switch element 80 and the system main relays SMR-B and SMR-G are turned on, the second switch element 66 is turned from on to off. When switched, system main relays SMR-B and SMR-G are turned off.

  According to the present embodiment, when the IC 61 detects the overcharge state of the unit cell 11, the output signal (alarm signal) of the IC 61 is input to the second switch element 66, whereby the system main relays SMR-B, SMR- G can be switched from on to off. Thereby, it can prevent that charging / discharging is performed with respect to the assembled battery 10 containing the cell 11 of an overcharge state.

  In this embodiment, when an alarm signal is output from the alarm confirmation circuit 63, the alarm signal is held in the alarm latch circuit 64. That is, after the alarm signal is output from the alarm confirmation circuit 63, the signal is continuously output from the alarm latch circuit 64, and the system main relays SMR-B and SMR-G remain off.

  In this embodiment, components (the monitoring IC 40 and the current interruption circuit 60) connected to the high-voltage assembled battery 10 are collectively mounted on one substrate 30. Accordingly, the first voltage detection line L1 and the second voltage detection line L2 can be collectively formed on one substrate 30. And the board | substrate 30 and the assembled battery 10 can be connected using the voltage detection line by which the 1st voltage detection line L1 and the 2nd voltage detection line L2 were made common. As a result, the number of voltage detection lines arranged outside the substrate 30 can be reduced as compared with the case where the monitoring IC 40 and the current cutoff circuit 60 are mounted on separate substrates 30.

  Next, a battery system that is Embodiment 2 of the present invention will be described. In the present embodiment, the same components as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Hereinafter, differences from the first embodiment will be mainly described.

  In the first embodiment, one assembled IC 40 and one current interruption circuit 60 are provided for the assembled battery 10. In the present embodiment, a plurality of monitoring ICs 40 and a plurality of current interruption circuits 60 are provided for the assembled battery 10. FIG. 3 shows a part of the configuration of the battery system of this example. In FIG. 3, a part of the first voltage detection line L1 and the second voltage detection line L2 is omitted.

  Each substrate 30 is connected to a part of the cells 11 included in the assembled battery 10 through a voltage detection line in which the first voltage detection line L1 and the second voltage detection line L2 are shared. Here, the number of unit cells 11 connected to each substrate 30 can be set as appropriate. The photocoupler 50 included in each of the plurality of substrates 30 is connected to the ECU 70, and an output signal of each photocoupler 50 is input to the ECU 70. Thereby, ECU70 can grasp | ascertain the voltage value of each single battery 11, and can control charging / discharging of the assembled battery 10. FIG.

  The second switch elements 66 of the current interrupt circuit 60 included in each of the plurality of substrates 30 are connected in series to the power supply 100. For this reason, when the second switch element 66 of any of the current interrupting circuits 60 is turned off, the energization from the power supply 100 to the exciting coil 91 is interrupted.

  According to this embodiment, when a failure occurs in any one of the substrates 30 by using the plurality of substrates 30, only the substrate 30 needs to be replaced. Moreover, since the structure of each board | substrate 30 is the same regarding the some board | substrate 30, it is only necessary to manufacture the board | substrate 30 of the same structure.

10: assembled battery. 11: single cell, 20: load, 30: substrate, 40: monitoring IC,
50: Photocoupler, 60: Current interruption circuit, 61: IC, 62: OR circuit,
63: Alarm confirmation circuit, 64: Alarm latch circuit, 65: Photocoupler,
66: second switch element, 70: ECU, 71: microcomputer, 80: first switch element,
100: power supply, 91: exciting coil, 92: movable contact, 93: fixed contact

Claims (1)

A power storage device including a plurality of power storage elements electrically connected in series;
A relay that connects the power storage device to a load when the excitation coil is energized, and that disconnects the connection between the power storage device and the load when the excitation coil is not energized;
A controller that controls a first switch element that switches between ON to allow energization of the excitation coil and OFF to block energization of the excitation coil;
A voltage detection circuit that detects a voltage value of each power storage element used to control charging and discharging of the power storage device using a first voltage detection line;
A current cutoff circuit including a second switch element that cuts off the energization of the exciting coil when the voltage value of the power storage element detected using the second voltage detection line is higher than a threshold value;
The power storage system, wherein the voltage detection circuit and the current cut-off circuit are mounted on the same substrate, and the first voltage detection line and the second voltage detection line are branched on the substrate.

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