JP2015023762A - Power storage system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that when a plurality of relays are operated by one drive circuit, the plurality of relays may remain under an electric conduction state due to a failure of the drive circuit.SOLUTION: A power storage system includes: a drive circuit (30) that drives a first relay (SMR-B) and a second relay (SMR-G); and a controller (40) that controls an operation of the drive circuit. The drive circuit includes: a coil (31) that receives electric power supplied from a power supply (32) and generates an electromagnetic force for switching the first relay and the second relay from a non-electric conduction state to an electric conduction state; a plurality of switch elements (SW1 and SW2) that are provided for a current path between the power supply and the coil and are connected to each other in series; and sensors (33, 34, and 35) that change an output signal in accordance with whether each of the switch elements is under the electric conduction state or the non-electric conduction state. The controller outputs a control signal for setting each of the switch elements under the non-electric conduction state and determines, on the basis of the output signal of the sensors, whether each of the switch elements is under the electric conduction state.

Description

  The present invention relates to a power storage system capable of operating a plurality of relays together.

  Patent Document 1 describes a relay that operates a plurality of contact pairs using a single drive mechanism (solenoid). Each contact pair is composed of a movable contact and a fixed contact. By switching between energization and non-energization of the solenoid, the movable contact can be brought into contact with the fixed contact or the movable contact can be separated from the fixed contact in a plurality of contact pairs.

  Patent Document 1 describes a power supply circuit that connects a battery to an inverter and a motor. In this power supply circuit, a plus-side main relay and a minus-side main relay are used, and these main relays form the contact pair described above.

JP 2005-222871 A

  In order to switch between energization and non-energization of the solenoid, a switch element is usually used. Specifically, when the switch element is turned on (on), a current can be passed through the solenoid. In addition, if the switch element is in a non-energized state (off), the energization of the solenoid can be cut off.

  Here, if the switch element remains in an energized state due to a failure of the switch element, a current continues to flow through the solenoid, and in a plurality of contact pairs, the movable contact continues to contact the fixed contact. In the power supply circuit described in Patent Document 1, the plus side main relay and the minus side main relay remain energized, and the battery remains connected to the inverter and the motor. In other words, the connection between the battery and the inverter cannot be cut off. When such a state occurs, for example, power may continue to be supplied from the inverter to the battery, and the battery may be overcharged.

  On the other hand, when the switch element remains energized due to the failure of the switch element, it is also necessary to determine this failure.

  The power storage system according to the present invention includes a first relay, a second relay, a drive circuit that drives the first relay and the second relay, and a controller that controls the operation of the drive circuit. The first relay is provided on a positive line that connects the positive terminal of the power storage device to the load, and the second relay is provided on a negative line that connects the negative terminal of the power storage device to the load. The first relay and the second relay are mechanically interlocked, and the drive circuit operates the first relay and the second relay together.

  The drive circuit has a coil and a plurality of switch elements. The coil receives an electric power supply from a power source and generates an electromagnetic force. This electromagnetic force is used to switch the first relay and the second relay from the non-energized state to the energized state. The plurality of switch elements are provided in a current path between the power source and the coil, and are connected in series with each other.

  In the present invention, a plurality of switch elements are provided in the current path between the power source and the coil. For this reason, even if some switch elements fail and remain energized, the remaining switch elements (ie, non-failed switch elements) can be switched between energized and de-energized states, Electric power can be supplied to the coil, or power supply to the coil can be cut off.

  If power is continuously supplied to the coil, the first relay and the second relay remain energized, and the power storage device and the load remain connected. In the present invention, as described above, the power supply to the coil can be cut off using the switch element that is not malfunctioning. For this reason, it can prevent that a 1st relay and a 2nd relay remain in an energized state. Here, when the load supplies power to the power storage device, the power storage device can be prevented from being overcharged by preventing the power storage device and the load from being connected.

  In the present invention, the drive circuit has a sensor, and the output signal of the sensor changes according to the energized state and the non-energized state of the switch element. Here, the controller outputs a control signal for making each switch element in a non-energized state, and determines whether or not each switch element is in an energized state based on the output signal of the sensor. If a control signal for turning off the switch element is output and it is confirmed that the switch element is in the energized state, it can be determined that the switch element has failed in the energized state.

  When determining the failure of the switch element, since a control signal for turning off the switch element is output, power is not supplied to the coil unless the switch element has failed. Thereby, it is possible to determine whether or not the switch element has failed without operating the first relay and the second relay. Here, it can be determined that the switch element has not failed.

  As the number of operations of the first relay and the second relay increases, the first relay and the second relay wear. If the failure of the switch element is determined without operating the first relay and the second relay as in the present invention, the wear (deterioration) of the first relay and the second relay can be suppressed.

  The plurality of switch elements can be composed of a first switch element and a second switch element. Here, both ends of the first switch element can be connected to the power source and the second switch element, respectively. Both ends of the second switch element can be connected to the first switch element and the coil, respectively. Here, it is possible to determine whether or not the first switch element and the second switch element are in an energized state using a voltage sensor (a first voltage sensor or a second voltage sensor).

  The first voltage sensor detects a voltage value between a connection point of the first switch element and the second switch element and the ground. The second voltage sensor detects a voltage value between the connection point of the second switch element and the coil and the ground. By comparing the voltage values detected by the first voltage sensor and the second voltage sensor with the voltage value of the power supply, it can be determined whether or not the first switch element and the second switch element are in the energized state.

  Specifically, when the control signal for energizing the first switch element and the control signal for deenergizing the second switch element are output and the second switch element is in an energized state, The voltage value detected by the second voltage sensor reaches the voltage value of the power supply. Therefore, by determining whether or not the voltage value detected by the second voltage sensor is greater than or equal to the voltage value of the power supply, it is possible to determine whether or not the second switch element has failed in the energized state. That is, when the voltage value detected by the second voltage sensor is equal to or higher than the voltage value of the power supply, it is determined that the second switch element is in a failure state in the energized state.

  Further, when a control signal for deenergizing the first switch element and the second switch element is output, the voltage value detected by the first voltage sensor is the power supply if the first switch element fails in the energized state. The voltage value of is reached. For this reason, by determining whether or not the voltage value detected by the first voltage sensor is greater than or equal to the voltage value of the power supply, it is possible to determine whether or not the first switch element has failed in the energized state. That is, when the voltage value detected by the first voltage sensor is equal to or higher than the voltage value of the power supply, it is determined that the first switch element is in a failure state in the energized state.

  As described above, when determining the failure of the first switch element and the second switch element, it is only necessary to switch only the first switch element between the energized state and the non-energized state. Here, the failure of the first switch element and the second switch element can be determined by switching both the first switch element and the second switch element between the energized state and the non-energized state.

  For example, when determining the failure of the first switch element, after outputting a control signal for deenergizing the first switch element and a control signal for energizing the second switch element, The energized state can be determined. Further, when determining the failure of the second switch element, after outputting a control signal for energizing the first switch element and a control signal for deenergizing the second switch element, The energized state can be determined. Here, by using the current sensor to determine whether or not current is flowing through the coil, it is possible to determine the energization state of the switch element described above. Specifically, when a current is flowing through the coil, it can be determined that the switch element is in an energized state.

  However, if only the first switch element is switched between the energized state and the non-energized state and the failure of the first switch element and the second switch element is determined, the number of operations of the switch element can be reduced, and the failure is determined. Can be shortened. Here, when a switch element having a movable contact and a fixed contact is used as the switch element, the wear (deterioration) of the switch element can be suppressed by reducing the number of times the switch element is operated. A semiconductor switch can also be used as the switch element.

It is a figure which shows the structure of a battery system. It is a figure which shows the structure of the circuit which drives a system main relay. It is a figure which shows the other structure of a battery system. It is a flowchart which shows the process which discriminate | determines the failure of a switch element. 5 is a timing chart showing behaviors of a switch element and a system main relay in the process shown in FIG. It is a flowchart which shows the process which discriminate | determines the failure of a switch element. FIG. 7 is a timing chart showing behaviors of a switch element and a system main relay in the process shown in FIG. 6. It is a figure which shows the structure of the circuit which drives a system main relay. It is a flowchart which shows the process which discriminate | determines the failure of a switch element.

  Examples of the present invention will be described below.

  The battery system in Example 1 of this invention is demonstrated using FIG. FIG. 1 is a schematic diagram showing the configuration of the battery system in the present embodiment.

  A positive electrode line PL is connected to a positive electrode terminal of the assembled battery (corresponding to the power storage device of the present invention) 10, and a negative electrode line NL is connected to a negative electrode terminal of the assembled battery 10. The assembled battery 10 has a plurality of single cells, and the number of single cells can be set as appropriate. Here, the plurality of single cells constituting the assembled battery 10 can be electrically connected in series or electrically connected in parallel.

  Note that a single cell can be used instead of the assembled battery 10. As the single battery, a secondary battery such as a nickel metal hydride battery or a lithium ion battery can be used. An electric double layer capacitor can be used instead of the secondary battery.

  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 power from the assembled battery 10. Moreover, when the load 20 produces | generates electric power, the assembled battery 10 can be charged using this electric power.

  The positive line PL is provided with a system main relay (corresponding to the first relay of the present invention) SMR-B, and the negative line NL is provided with a system main relay (corresponding to the second relay of the present invention) SMR-G. Is provided. When system main relays SMR-B and SMR-G are on (energized state), battery pack 10 is connected to load 20. Further, when the system main relays SMR-B and SMR-G are off (non-energized state), the connection between the assembled battery 10 and the load 20 is cut off.

  The assembled battery 10 can be mounted on a vehicle, for example. Here, a motor / generator can be used as the load 20. The motor / generator receives electric power from the assembled battery 10 and generates kinetic energy for running the vehicle. This kinetic energy is transmitted to the wheels. Further, when the vehicle is braked, the motor / generator generates electric power, and this electric power is supplied to the assembled battery 10.

  Next, a circuit (drive circuit) for driving the system main relays SMR-B and SMR-G will be described with reference to FIG.

  System main relay SMR-B has movable contact MC1 and fixed contact FC1, and fixed contact FC1 is connected to positive electrode line PL. When the movable contact MC1 comes into contact with the fixed contact FC1, the system main relay SMR-B is turned on. When the movable contact MC1 is separated from the fixed contact FC1, the system main relay SMR-B is turned off.

  The system main relay SMR-G has a movable contact MC2 and a fixed contact FC2, and the fixed contact FC2 is connected to the negative electrode line NL. When the movable contact MC2 comes into contact with the fixed contact FC2, the system main relay SMR-G is turned on. When the movable contact MC2 is separated from the fixed contact FC2, the system main relay SMR-G is turned off.

  A drive circuit 30 for driving the system main relays SMR-B, SMR-G has a coil 31 and switch elements SW1, SW2. When a current is passed through the coil 31, an electromagnetic force can be generated, and the movable contacts MC1 and MC2 can be moved using the electromagnetic force.

  As the structures of the system main relays SMR-B and SMR-G, known structures can be used as appropriate, and detailed description thereof is omitted. In this embodiment, the movable contacts MC1 and MC2 are mechanically connected, and the movable contact MC1 moves together with the movable contact MC2. That is, the movable contacts MC1 and MC2 are mechanically interlocked. For this reason, a common coil 31 is used in the system main relays SMR-B and SMR-G. That is, by passing a current through the coil 31, the movable contacts MC1 and MC2 can be moved together and brought into contact with the fixed contacts FC1 and FC2. When no current flows through the coil 31, the movable contacts MC1, MC2 can be separated from the fixed contacts FC1, FC2 by an urging mechanism using a spring or the like.

  One end of the coil 31 is grounded, and the other end of the coil 31 is electrically connected to the power source 32 via the power supply line SL. Thereby, power from the power supply 32 is supplied to the coil 31. As the power source 32, the assembled battery 10 can be used, or a power source different from the assembled battery 10 can be used. When the electromotive voltage of the assembled battery 10 is too high, the voltage value of the assembled battery 10 can be stepped down and the electric power after the step-down can be supplied to the coil 31.

  The power supply line SL is provided with switch elements SW1 and SW2. The switch elements SW1 and SW2 are electrically connected in series. The switch elements SW1 and SW2 are switched between ON (energized state) and OFF (non-energized state) in response to a control signal from the controller 40.

  As the switch elements SW1 and SW2, so-called mechanical switches or semiconductor switches (for example, transistors) can be used. The mechanical switch has a movable contact and a fixed contact. When the movable contact contacts the fixed contact, the switch elements (mechanical switches) SW1 and SW2 are turned on. Further, when the movable contact is separated from the fixed contact, the switch elements (mechanical switches) SW1 and SW2 are turned off. The semiconductor switch is switched between on and off according to the ion movement state.

  One end of the switch element (corresponding to the first switch element of the present invention) SW1 is connected to the power source 32, and the other end of the switch element SW1 is one end of the switch element (corresponding to the second switch element of the present invention) SW2. Connected with. The other end of the switch element SW2 is connected to the coil 31.

  A voltage sensor (corresponding to the first voltage sensor of the present invention) 33 is connected to a connection point between the switch element SW1 and the switch element SW2. The voltage sensor 33 detects a voltage value V1 between the connection point of the switch elements SW1 and SW2 and the ground. A voltage sensor (corresponding to a second voltage sensor of the present invention) 34 is connected to a connection point between the switch element SW2 and the coil 31. The voltage sensor 34 detects a voltage value V2 between the connection point of the switch element SW2 and the coil 31 and the ground. Output signals from the voltage sensors 33 and 34 are input to the controller 40.

  In this embodiment, since the common coil 31 is used for the system main relays SMR-B and SMR-G, the power consumption of the coil 31 can be reduced. Specifically, the power consumption of the coil 31 can be reduced as compared with the case where the coil 31 is provided for each of the system main relays SMR-B and SMR-G. When one coil 31 is used, the overall size of the coil 31 can be easily reduced compared to when two coils 31 are used. Accordingly, the power consumption when using one coil 31 tends to be lower than the power consumption when using two coils 31.

  On the other hand, assuming that the circuit that supplies power to the coil 31 fails, there is a possibility that a current continues to flow through the coil 31. If the current continues to flow through the coil 31, the system main relays SMR-B and SMR-G remain on, and the assembled battery 10 remains connected to the load 20. If the assembled battery 10 remains connected to the load 20, for example, power from the load 20 may continue to be supplied to the assembled battery 10, and the assembled battery 10 may be overcharged.

  In the present embodiment, the switch elements SW1 and SW2 are connected in series in the power supply line SL. When only one of the switch elements SW1 and SW2 is provided, a current may continue to flow through the coil 31 due to the failure of the switch element. The failure of the switch element here (hereinafter referred to as ON failure) refers to a state in which the switch element remains on despite the control to turn off the switch element.

  By providing the switch elements SW1 and SW2 as in this embodiment, even if one switch element is turned on, the other switch element can be turned off. Thereby, it can prevent that an electric current continues flowing into the coil 31, and can interrupt the connection of the assembled battery 10 and the load 20. FIG. In this embodiment, two switch elements SW1 and SW2 are provided, but the number of switch elements may be two or more. If two or more switch elements are connected in series, the remaining switch elements can be turned off even if some of the switch elements cause an on failure.

  The present invention can be applied not only to the battery system shown in FIG. 1 but also to the battery system shown in FIG. 3, for example. In the battery system shown in FIG. 3, system main relay SMR-P and resistance element R are electrically connected in parallel to system main relay SMR-G. Here, system main relay SMR-P and resistance element R are electrically connected in series. The structure of the system main relay SMR-P can be the same as that of the system main relays SMR-B and SMR-G.

  The resistance element R is used for suppressing the inrush current from flowing when the assembled battery 10 is connected to the load 20. When connecting the assembled battery 10 to the load 20, the system main relay SMR-P is switched from OFF to ON before the system main relay SMR-G is switched from OFF to ON. Thereby, an electric current can be sent through resistance element R, and it can control that an inrush current flows. After passing a current through the resistance element R, the system main relay SMR-G may be switched from OFF to ON. Further, when the system main relay SMR-G is turned on, the system main relay SMR-P may be switched from on to off.

  In the battery system shown in FIG. 3, system main relays SMR-B and SMR-G are operated together or system main relays SMR-B and SMR-P are operated together using one coil 31. be able to. When system main relays SMR-B and SMR-P are operated together, system main relay SMR-P corresponds to the second relay of the present invention.

  Here, the system main relay to be operated together may be a system main relay that allows the assembled battery 10 to be connected to the load 20 and to be charged and discharged. That is, the system main relays (at least two) provided in each of the positive electrode line PL and the negative electrode line NL may be operated together.

  Next, processing for determining an on failure of the switch elements SW1 and SW2 will be described with reference to the flowchart shown in FIG. The process shown in FIG. 4 is executed by the controller 40. When the processing shown in FIG. 4 is started, the switch elements SW1 and SW2 are turned off. For example, when the assembled battery 10 is not connected to the load 20, the process shown in FIG. 4 can be performed.

  In step S101, the controller 40 outputs a control signal for switching the switch element SW1 from OFF to ON. An OFF control signal from the controller 40 is input to the switch element SW2.

  In step S102, the controller 40 detects the voltage value V2 based on the output signal of the voltage sensor 34, and determines whether or not the voltage value V2 is lower than the voltage value Vb. The voltage value Vb is a voltage value of the power supply 32. The controller 40 may detect the voltage value Vb before performing the comparison with the voltage value V2. Under this condition, the timing for detecting the voltage value Vb can be set as appropriate. For example, when starting the process shown in FIG. 4, the controller 40 can detect the voltage value Vb in advance.

  When the voltage value V2 is lower than the voltage value Vb, the controller 40 performs the process of step S103. When the voltage value V2 is equal to or higher than the voltage value Vb, the controller 40 performs the process of step S104. When the switch element SW2 is off, the voltage value V2 is substantially 0 [V], and the voltage value V2 is lower than the voltage value Vb. Substantially 0 [V] means that a detection error of the voltage sensor 34 is included. When the voltage value V2 is lower than the voltage value Vb, it can be seen that the switch element SW2 is operating according to the control signal from the controller 40. For this reason, the controller 40 determines in step S103 that the switch element SW2 is normal.

  On the other hand, when the switch element SW2 is in an on failure, the power from the power source 32 is supplied to the coil 31, and the voltage value V2 becomes substantially equal to the voltage value Vb. Substantially equal means that a detection error of the voltage sensor 34 and an error when the voltage value Vb is detected are included. As described above, the voltage value V2 is different between when the switch element SW2 is normal and when the switch element SW2 is in an on failure.

  When the voltage value V2 is equal to or higher than the voltage value Vb, it can be seen that the switch element SW2 is turned on even though the OFF control signal is output to the switch element SW2. For this reason, the controller 40 determines in step S104 that the switch element SW2 has an on failure. After performing the process of step S104, the controller 40 ends the process shown in FIG.

  In step S105, the controller 40 outputs a control signal for switching the switch element SW1 from on to off. Here, the OFF control signal remains output to the switch element SW2. In step S106, the controller 40 detects the voltage value V1 based on the output signal of the voltage sensor 33, and determines whether or not the voltage value V1 is lower than the voltage value Vb. As described above, the voltage value Vb is the voltage value of the power supply 32.

  When the voltage value V1 is lower than the voltage value Vb, the controller 40 performs the process of step S107. When the voltage value V1 is greater than or equal to the voltage value Vb, the controller 40 performs the process of step S108. In the process of step S105, since the control signal for turning off the switch elements SW1 and SW2 is output, if the switch element SW1 is normal, the voltage value V1 becomes approximately 0 [V], and the voltage value V1 is the voltage value. It becomes lower than Vb. Substantially 0 [V] means that a detection error of the voltage sensor 33 is included. In step S107, the controller 40 determines that the switch element SW1 is normal.

  When the switch element SW1 has an on failure, the voltage value V1 is substantially equal to the voltage value Vb. Substantially equal means that a detection error of the voltage sensor 33 and an error when the voltage value Vb is detected are included. Since the voltage value V1 is equal to or higher than the voltage value Vb, the controller 40 determines in step S108 that the switch element SW1 has an on failure. As described above, the voltage value V1 is different between when the switch element SW1 is normal and when the switch element SW1 has an on failure. After performing the processing of steps S107 and S108, the controller 40 ends the processing shown in FIG.

  FIG. 5 is a timing chart when the processing shown in FIG. 4 is performed. FIG. 5 shows the behavior of the switch elements SW1 and SW2 and the system main relays SMR-B and SMR-G when the switch elements SW1 and SW2 are normal.

  As shown in FIG. 5, during the control for turning on the switch element SW1, it is possible to determine the on failure of the switch element SW2. That is, it is possible to determine the on failure of the switch element SW2 by checking the energized state of the switch element SW2 while performing the control to turn off the switch element SW2.

  Further, after performing the control to switch the switch element SW1 from on to off, it is possible to determine the on failure of the switch element SW1. That is, it is possible to determine the on failure of the switch element SW1 by checking the energized state of the switch element SW1 while performing the control to turn off the switch element SW1.

  As shown in FIG. 5, when the switch elements SW1 and SW2 are normal, the system main relays SMR-B and SMR-G remain off. That is, when the switch elements SW1 and SW2 are normal, the system main relays SMR-B and SMR-G are not switched from OFF to ON when determining ON failure of the switch elements SW1 and SW2.

  Even if the switch elements SW1 and SW2 are normal, if the system main relays SMR-B and SMR-G are switched between OFF and ON in order to determine the ON failure of the switch elements SW1 and SW2, the system main Deterioration of the relays SMR-B and SMR-G is advanced. That is, since the number of times that the movable contacts MC1 and MC2 are operated increases, there is a possibility that the wear of the movable contacts MC1 and MC2 and the wear of the fixed contacts FC1 and FC2 may be advanced.

  In this embodiment, as described above, the system main relays SMR-B and SMR-G can be kept off when determining the on failure of the switch elements SW1 and SW2, so that the system main relay SMR- B, SMR-G deterioration can be suppressed.

  In this embodiment, the on failure of the switch elements SW1 and SW2 is determined in the order shown in FIG. 4, but the present invention is not limited to this. Specifically, after performing the processes of steps S105 to S107, the processes of steps S101 to S104 can be performed. That is, after determining the on failure of the switch element SW1, it is possible to determine the on failure of the switch element SW2.

  In the processes of steps S104 and S108, when an on failure of the switch elements SW1 and SW2 is specified, a warning can be given to the user or the like. As a warning for the user or the like, a known method can be appropriately adopted.

  For example, sound or display can be used as a warning means. Specifically, by generating sound, the user or the like can recognize that the switch elements SW1 and SW2 are out of order. Further, by displaying predetermined information on the display, the user or the like can recognize that the switch elements SW1 and SW2 are out of order. Here, it is not necessary for the user or the like to recognize the specific content of the failure, but it is also possible to make the user or the like only recognize that some kind of failure has occurred.

  On the other hand, when it is determined that both switch elements SW1 and SW2 are on-failure, system main relays SMR-B and SMR-G remain on. In this case, in addition to the above-described warning, for example, it is possible to perform a process of restricting the input of the assembled battery 10 and suppressing the assembled battery 10 from being overcharged. This process can be performed by the controller 40.

  Next, another process for determining the ON failure of the switch elements SW1 and SW2 will be described with reference to the flowchart shown in FIG. The process shown in FIG. 6 is executed by the controller 40. When the processing shown in FIG. 6 is started, the switch elements SW1 and SW2 are turned off.

  In step S201, the controller 40 outputs a control signal for switching the switch element SW2 from OFF to ON. An off control signal is still output to the switch element SW1. In step S202, the controller 40 detects the voltage value V1 based on the output signal of the voltage sensor 33, and determines whether or not the voltage value V1 is lower than the voltage value (voltage value of the power supply 32) Vb.

  In the process of step S201, since the switch element SW1 is controlled to be off, if the switch element SW1 is operating according to this control, the voltage value V1 becomes approximately 0 [V]. That is, since the voltage value V1 is lower than the voltage value Vb, the controller 40 determines in step S203 that the switch element SW1 is normal.

  On the other hand, when the switch element SW1 has an on-failure, the voltage value V1 is substantially equal to the voltage value Vb. That is, since the voltage value V1 is equal to or higher than the voltage value Vb, the controller 40 determines in step S204 that the switch element SW1 has an on failure.

  In step S205, the controller 40 outputs a control signal for switching the switch element SW1 from OFF to ON, and outputs a control signal for switching the switch element SW2 from ON to OFF. In step S206, the controller 40 detects the voltage value V2 based on the output signal of the voltage sensor 34, and determines whether or not the voltage value V2 is lower than the voltage value (voltage value of the power supply 32) Vb.

  If the switch elements SW1 and SW2 operate according to the processing in step S205, the voltage value V2 becomes substantially 0 [V]. That is, since the voltage value V2 is lower than the voltage value Vb, the controller 40 determines in step S207 that the switch element SW2 is normal.

  On the other hand, when the switch element SW2 is in an on-failure state even though the switch element SW2 is turned off, power is supplied to the coil 31 because the switch element SW1 is on. Thereby, the voltage value V2 becomes substantially equal to the voltage value Vb. Since the voltage value V2 is equal to or higher than the voltage value Vb, the controller 40 determines in step S208 that the switch element SW2 has an on failure. After performing the processes of steps S204, S207, and S208, the controller 40 ends the process shown in FIG.

  FIG. 7 is a timing chart when the processing shown in FIG. 6 is performed. FIG. 7 shows the behavior of the switch elements SW1 and SW2 and the system main relays SMR-B and SMR-G when the switch elements SW1 and SW2 are normal.

  As shown in FIG. 7, during the control for turning on the switch element SW2, it is possible to determine the on failure of the switch element SW1. That is, it is possible to determine the on failure of the switch element SW1 by checking the energized state of the switch element SW1 while performing the control to turn off the switch element SW1.

  Further, during the control for turning on the switch element SW1, it is possible to determine the on failure of the switch element SW2. That is, it is possible to determine the on failure of the switch element SW2 by checking the energized state of the switch element SW2 while performing the control to turn off the switch element SW2.

  When the processing shown in FIG. 6 is performed, if the switch elements SW1 and SW2 are normal, the system main relays SMR-B and SMR-G remain off. For this reason, similarly to the processing shown in FIG. 4, the number of operations of the system main relays SMR-B and SMR-G can be reduced, and deterioration of the system main relays SMR-B and SMR-G can be suppressed.

  In the process shown in FIG. 6, the on failure of the switch elements SW1 and SW2 is determined based on the output signals of the voltage sensors 33 and 34, but the present invention is not limited to this. Specifically, as shown in FIG. 8, the voltage sensors 33 and 34 can be omitted, and the current sensor 35 can be disposed in the current path between the switch element SW <b> 2 and the coil 31. The output signal of the current sensor 35 is input to the controller 40, and the controller 40 can detect the current value I.

  The current sensor 35 is used to determine whether or not a current is flowing through the coil 31. For this reason, the position where the current sensor 35 is provided is not limited to the position shown in FIG. Specifically, the current sensor 35 can be provided in the power supply line SL on the side where the coil 31 is grounded.

  In the configuration shown in FIG. 8, when control is performed to turn on one of the switch elements SW1 and SW2 and turn off the other, if the switch elements SW1 and SW2 are normal, no current flows through the coil 31. At this time, the current value I detected by the current sensor 35 is approximately 0 [A]. Substantially 0 [A] means that a detection error of the current sensor 35 is included.

  When control is performed to turn on one of the switch elements SW1 and SW2 and turn off the other, the current flows through the coil 31 when the other switch element has an on failure. At this time, the current value I is equal to the current value supplied from the power supply 32 to the coil 31.

  In the configuration shown in FIG. 8, the processing shown in FIG. 9 can be performed when determining the on failure of the switch elements SW <b> 1 and SW <b> 2. The process shown in FIG. 9 corresponds to the process shown in FIG. 6, and the same reference numerals are used for the same processes as those shown in FIG.

  In the process shown in FIG. 9, the processes of steps S209 and 210 are performed instead of the processes of steps S202 and S206 shown in FIG. In steps S209 and 210, the controller 40 determines whether or not a current is flowing through the coil 31 based on the output signal of the current sensor 35. By comparing the current value I detected by the current sensor 35 with a threshold value, it can be determined whether or not a current is flowing through the coil 31.

  Specifically, when the current value I is smaller than the threshold value, it can be determined that no current flows through the coil 31. Further, when the current value I is equal to or greater than the threshold value, it can be determined that a current is flowing through the coil 31. Here, the threshold value can be set to 0 [A], or can be set to a value other than 0 [A] in consideration of the detection error of the current sensor 35.

  When it is determined in step S209 that no current is flowing through the coil 31, the controller 40 determines in step S203 that the switch element SW1 is normal. When it is determined in step S209 that no current is flowing through the coil 31, the controller 40 determines in step S204 that the switch element SW1 has an ON failure. Thus, the output signal of the current sensor 35 changes between when the switch element SW1 is normal and when the switch element SW1 is on-failure.

  When it is determined in step S210 that no current is flowing through the coil 31, the controller 40 determines in step S207 that the switch element SW2 is normal. When it is determined in step S210 that no current is flowing through the coil 31, the controller 40 determines in step S208 that the switch element SW2 has an on failure. Thus, the output signal of the current sensor 35 changes between when the switch element SW2 is normal and when the switch element SW2 is on.

  In the processes shown in FIGS. 6 and 9, the processes in steps S205 and S203 are performed after the processes in steps S201 to S203. However, the present invention is not limited to this. Specifically, after performing the processes of steps S205 to S207, the processes of steps S201 to S204 may be performed.

  As can be seen from the comparison between FIGS. 5 and 7, in the process shown in FIG. 6, the switch elements SW1 and SW2 must be switched between on and off. In the process shown in FIG. 4, the switch element SW1 is turned on and off. Just switch between off. Therefore, according to the process shown in FIG. 4, the number of times of operating the switch elements SW <b> 1 and SW <b> 2 can be reduced as compared with the process shown in FIG. 6.

  If the number of operations of the switch elements SW1 and SW2 is reduced, the time required for determining the failure of the switch elements SW1 and SW2 can be shortened. Further, when the switch elements SW1 and SW2 are mechanical switches, the deterioration of the switch elements SW1 and SW2 can be suppressed by reducing the number of operations of the switch elements SW1 and SW2. As described above, in the mechanical switch, since the movable contact contacts the fixed contact, if the number of operations of the mechanical switch increases, the wear of the movable contact and the fixed contact proceeds.

  In this embodiment, the on failure is determined for the two switch elements SW1 and SW2, but the present invention is not limited to this. That is, the present invention can be applied even when three or more switch elements are used. A control signal for turning off the switch element may be output to an arbitrary switch element to determine whether or not the switch element is on. Whether the switch element is on or not can be determined by using the detection result of the voltage sensor or current sensor, as in the present embodiment.

10: assembled battery, 20: load, 31: coil, 32: power supply, 33, 34: voltage sensor,
40: Controller, PL: Positive line, NL: Negative line, SL: Power supply line,
SMR-B, SMR-G, SMR-P: System main relay,
MC1, MC2: movable contact, FC1, FC2: fixed contact, SW1, SW2: switch element

Claims (8)

A first relay provided on a positive line connecting the positive terminal of the power storage device to the load;
A second relay that is provided in a negative electrode line connecting a negative terminal of the power storage device to the load, and mechanically interlocks with the first relay;
A drive circuit for driving the first relay and the second relay;
A controller for controlling the operation of the drive circuit,
The drive circuit is
A coil that receives an electric power supply from a power source and generates an electromagnetic force for switching the first relay and the second relay from a non-energized state to an energized state;
A plurality of switch elements provided in a current path between the power source and the coil and connected in series with each other;
A sensor that changes an output signal in accordance with an energized state and a non-energized state of each switch element,
The controller outputs a control signal for making each switch element in a non-energized state, and determines whether or not each switch element is in an energized state based on an output signal of the sensor. system. The plurality of switch elements are a first switch element and a second switch element,
Both ends of the first switch element are connected to the power source and the second switch element, respectively, and both ends of the second switch element are connected to the first switch element and the coil, respectively.
The sensor includes: a first voltage sensor that detects a voltage value between a connection point of the first switch element and the second switch element and a ground; and a connection point of the second switch element and the coil and a ground. A second voltage sensor for detecting a voltage value therebetween,
The controller compares the voltage value detected by the first voltage sensor and the second voltage sensor with the voltage value of the power supply, thereby determining whether or not the first switch element and the second switch element are in an energized state. The power storage system according to claim 1, wherein the power storage system is determined.   The controller outputs a control signal for energizing the first switch element and a control signal for deenergizing the second switch element, and the voltage value detected by the second voltage sensor is the power source. 3. The power storage system according to claim 2, wherein when the voltage value is equal to or higher than the voltage value, it is determined that the second switch element has failed in an energized state.   The controller outputs a control signal for deenergizing the first switch element and the second switch element, and when the voltage value detected by the first voltage sensor is equal to or higher than the voltage value of the power source, The power storage system according to claim 2 or 3, wherein it is determined that the first switch element has failed in an energized state.   The controller outputs a control signal for de-energizing one of the plurality of switch elements and a control signal for energizing the other switch element, and based on an output signal of the sensor, The power storage system according to claim 1, wherein one of the switch elements is determined to be in an energized state. The sensor is a current sensor that detects a current flowing through the coil,
6. The controller according to claim 5, wherein when the controller determines that a current is flowing through the coil based on an output signal of the current sensor, the controller determines that the one switch element is in an energized state. Power storage system.   The power storage system according to claim 1, wherein the switch element is a switch element having a movable contact and a fixed contact or a semiconductor switch element.   The power storage system according to any one of claims 1 to 7, wherein the load supplies power to the power storage device.

Images