Charging and discharging control method, and charging and discharging control device

Abstract

To prevent an energized state of a relay 102 caused by a failure in a second relay switch circuit 30.SOLUTION: In a charging and discharging control device 1 connected to a load 101 via a relay 102, when an open state of the relay 102 is confirmed in a first period from a stop of a second relay switch circuit 30 to a stop of a first relay switch circuit 10 after operation of the load 101 is finished, the state is diagnosed as a normal state in which a second control unit 40 operates the second relay switch circuit 30 to bring the relay 102 into an open state. When a closed state of the relay 102 is confirmed in the first period, the state is diagnosed as an abnormal state in which the second control unit 40 cannot operate the second relay switch circuit 30 to bring the relay 102 into an open state.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a charge / discharge control method and a charge / discharge control device. [Background technology]

[0002] Conventionally, in a vehicle, there has been a relay opening / closing circuit (second relay opening / closing circuit) for backing up a first relay opening / closing circuit in case the first relay opening / closing circuit fails (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6302852 Summary of the Invention [Problem to be solved by the invention]

[0004] When a fault diagnosis of the second control unit is performed while the backup second relay opening / closing circuit is faulty, it is required to prevent the relay from changing from an open state to an energized state due to the fault in the second relay opening / closing circuit. [Means for solving the problem]

[0005] In the present invention, there is provided a charge / discharge control method performed by a charge / discharge control device connected to a load via a relay, the charge / discharge control device having a first relay opening / closing circuit and a second relay opening / closing circuit connected in series for opening and closing the relay, a first control unit for controlling the operation of the first relay opening / closing circuit, and a second control unit for controlling the operation of the second relay opening / closing circuit when fault information of the first control unit is input from the first control unit, and the charge / discharge control device checks the opening / closing state of the relay during a first period from when the second control unit stops the second relay opening / closing circuit until when the first control unit stops the first relay opening / closing circuit after the operation of the load has ended, and if it is confirmed that the relay is in an open state during the first period, it diagnoses that the relay is in a normal state in which the relay can be opened by the operation of the second relay opening / closing circuit under the control of the second control unit, and if it is confirmed that the relay is in a closed state during the first period, it diagnoses that the relay is in an abnormal state in which the relay cannot be opened by the operation of the second relay opening / closing circuit under the control of the second control unit. [Effects of the Invention]

[0006] According to the present invention, when a fault diagnosis of the second control unit is performed in a state in which the backup second relay opening / closing circuit is faulty, it is possible to prevent the relay from changing from an open state to an energized state due to the fault in the second relay opening / closing circuit. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of the configuration of a charge / discharge control device 1 according to an embodiment. [Figure 2] 3 is a timing chart showing an example of the operation of the charge / discharge control device 1 according to the embodiment. [Figure 3] 10 is a timing chart showing an example of the operation of a charge / discharge control device of a comparative technique. [Figure 4] 3A and 3B are diagrams showing examples of notifications from the charge / discharge control device 1 according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the accompanying drawings. In the drawings, the same components are denoted by the same reference numerals, and the description thereof will be omitted.

[0009] (Configuration of charge / discharge control device 1) The configuration of the charge / discharge control device 1 will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of the configuration of the charge / discharge control device 1 according to an embodiment.

[0010] The charge / discharge control device 1 is used in a device including a load 101, which is an electric device or the like, and a relay 102 connected to the load 101. Here, the load 101 is, for example, an in-vehicle device that operates at a voltage of 48 V or a vehicle drive motor that operates at a high voltage. The device including the load 101 and the relay 102 is, for example, a vehicle such as an electric vehicle (EV), a hybrid vehicle (HV), or a plug-in hybrid vehicle (PHV).

[0011] The charge / discharge control device 1 includes a first relay switching circuit 10, a first control unit 20, a second relay switching circuit 30, a second control unit 40, and an alarm unit 50. The first control unit 20 and the second control unit 40 are, for example, an MPU (Micro Processor Unit) or a PSIC (Power Supply Integrated Circuit). The charge / discharge control device 1 supplies power to a load 101 via a relay 102.

[0012] The second relay switching circuit 30 is a backup relay switching circuit for the first relay switching circuit 10, and is connected in series with the first relay switching circuit 10. By connecting the first relay switching circuit 10 and the second relay switching circuit 30 in series, when at least one of them is stopped, the relay 102 is opened.

[0013] The first relay switching circuit 10 switches the relay 102 on and off based on a first relay drive switch signal input from the relay driver 22 of the first control unit 20. The first relay switching circuit 10 and the second relay switching circuit 30 are connected in series. As a result, even if the relay 102 cannot be set to an open state (Open) due to a failure of the first control unit 20 or the first relay switching circuit 10, the second relay switching circuit 30 can set the relay 102 to an open state (Open).

[0014] The first control unit 20 has an error notification unit 21, a relay driving unit 22, and a diagnosis unit 23. When the first control unit 20 malfunctions, the error notification unit 21 outputs an ERROR signal indicating this malfunction to the second control unit 40. The ERROR signal is an example of failure information used by the first control unit 20 to notify the second control unit 40 of the malfunction of the first control unit 20.

[0015] The first control unit 20 can notify the second control unit 40 of a malfunction of the first control unit 20 by using the ERROR signal, and can also quasi-control the ON / OFF of the second relay drive switch signal output by the second control unit 40. That is, the first control unit 20 can forcibly turn OFF the second relay drive switch signal output by the second relay drive unit 41 of the second control unit 40 by using the ERROR signal, and cause the second relay opening / closing circuit 30 to open the relay 102.

[0016] The relay driving section 22 outputs a first relay driving switch signal to the first relay opening / closing circuit 10 to operate the first relay opening / closing circuit 10 .

[0017] The diagnosing unit 23 diagnoses whether the second control unit 40 is in a state in which it can operate normally when the operation (driving) of the load 101 or the device (vehicle) is finished, i.e., whether it is possible to turn the second relay drive switch signal ON and OFF to operate and stop the second relay opening / closing circuit 30. The diagnosing unit 23 also diagnoses whether it is possible to turn the first relay drive switch signal ON and OFF to operate and stop the first relay opening / closing circuit 10. These diagnoses are performed with reference to a relay state signal that indicates the open / closed state of the relay 102. The diagnosing unit 23 outputs these diagnosis results to the notifying unit 50.

[0018] The second relay switching circuit 30 switches the relay 102 on and off based on a second relay drive switch signal output from the second relay drive unit 41 of the second control unit 40. The second relay switching circuit 30 is connected in series with the first relay switching circuit 10. As a result, even if the relay 102 cannot be set to an open state (Open) due to a failure of the first control unit 20 or the first relay switching circuit 10, the second relay switching circuit 30 switches the relay 102 to an open state (Open) instead of the first relay switching circuit 10.

[0019] The second control unit 40 is a backup control unit for the first control unit 20, and includes a second relay driving unit 41. The second relay driving unit 41 is configured to be able to receive an ERROR signal from the first control unit 20, which indicates that the first control unit 20 has malfunctioned. The second relay driving unit 41 outputs a second relay driving switch signal that operates the second relay opening / closing circuit 30. Based on the ERROR signal output from the error notification unit 21 of the first control unit 20, the second control unit 40 forcibly turns OFF the second relay driving switch signal output by the second relay driving unit 41, causing the second relay opening / closing circuit 30 to set the relay 102 to an open state (Open).

[0020] It is assumed that a diagnosis is executed to determine whether the second control unit 40 is in a state in which it can operate normally, and that the diagnosis indicates that the relay 102 will not be in a normal state (no fault) in which it is in an open state. In this case, the notification unit 50 notifies the user that there is a possibility of a fault in the second control unit 40 or the second relay opening / closing circuit 30. The fault notification is made to the user by a screen display, a voice, or the like.

[0021] (Operation of the charge / discharge control device 1) The operation of the charge / discharge control device 1 will be described with reference to Figures 1 and 2. Figure 2 is a timing chart showing an example of the operation of the charge / discharge control device 1 of the embodiment.

[0022] In the fault diagnosis of the second control unit 40, consider a case where the relay 102 is opened when the vehicle operation is terminated (when the IG is OFF, after t11 (after the operation of the load has ended)). In this case, the error notification unit 21 of the first control unit 20 first outputs an ERROR signal that forcibly turns OFF the second relay drive switch signal. In response to the input of this ERROR signal, the second relay drive unit 41 of the second control unit 40 forcibly turns OFF the second relay drive switch signal (t12). The second relay opening / closing circuit 30 stops in response to the OFF second relay drive switch signal. If the relay 102 is normal, it will be in an open state (Open) after t12, and will cut off the power supply to the load 101.

[0023] In this state, the diagnosing unit 23 checks whether the relay 102 is in an open state, i.e., a normal state (no fault) (step S11 at t13). That is, the diagnosing unit 23 checks the open / closed state of the relay 102 during a first period from when the second control unit 40 stops the second relay switching circuit 30 to when the first control unit 20 stops the first relay switching circuit 10. If the diagnosing unit 23 confirms that the relay 102 is in an open state, it diagnoses that the relay 102 is in a normal state, in which the relay 102 can be opened by the operation of the second relay switching circuit 30 under the control of the second control unit 40. If the diagnosing unit 23 confirms that the relay 102 is not in an open state, it diagnoses that the relay 102 is in an abnormal state, in which the relay 102 cannot be opened by the operation of the second relay switching circuit 30 under the control of the second control unit 40. Thereafter, the relay driving unit 22 turns off the first relay driving switch signal (t14). The first relay switching circuit 10 stops in response to the OFF first relay driving switch signal.

[0024] Furthermore, in the fault diagnosis of the second control unit 40, after the first relay opening / closing circuit 10 has stopped, the first control unit 20 further outputs an ERROR signal that turns on the second relay drive switch signal. The second relay drive unit 41 turns on the second relay drive switch signal in response to the input of this ERROR signal (t15). The second relay opening / closing circuit 30 operates in response to the ON second relay drive switch signal. Since the first relay opening / closing circuit 10 has been stopped by the relay drive unit 22, the relay 102 is in an open state (Open) after t15 if normal.

[0025] In this state, the diagnosing unit 23 checks whether the relay 102 is in an open state, i.e., a normal state (no fault) (step S12 at t16). That is, the diagnosing unit 23 checks the open / closed state of the relay 102 during a second period after the first control unit 20 stops the first relay switching circuit 10 and the second control unit 40 operates the second relay switching circuit 30 again. If the diagnosing unit 23 determines that the relay 102 is in an open state, it diagnoses that the relay 102 is in a normal state in which the relay 102 can be placed in an open state by the operation of the first relay switching circuit 10 under the control of the first control unit 20. If the diagnosing unit 23 determines that the relay 102 is not in an open state, it diagnoses that the relay 102 is in an abnormal state in which the relay 102 cannot be placed in an open state by the operation of the first relay switching circuit 10 under the control of the first control unit 20.

[0026] That is, the first control unit 20 performs a fault diagnosis on the second control unit 40 when turning off the relay 102 in the discharge state. When switching the relay 102 from closed to open in the discharge state, the first control unit 20 first turns off the second relay drive switch signal to open the relay 102. Then, the first relay drive switch signal is turned off. Then, the second relay switch signal is turned on (the relay 102 remains open).

[0027] (Operation of power supply control device of comparison technology) An example of the operation of the charge / discharge control device of the comparative technology will be described with reference to Fig. 3, in comparison with the operation of the charge / discharge control device 1 of the embodiment. Fig. 3 is a timing chart showing an example of the operation of the charge / discharge control device of the comparative technology. The charge / discharge control device of the comparative technology also has the same configuration as the charge / discharge control device 1 of the embodiment, and only differs in processing function, so the configuration and symbols of the charge / discharge control device 1 will be used for the description.

[0028] In the comparison technique, in the fault diagnosis of the second control unit 40, when the vehicle operation is terminated (when the IG is turned off, after t21 (after the load operation is terminated)), the relay driving unit 22 first turns off the first relay driving switch signal (t22). The first relay opening / closing circuit 10 stops in response to the OFF first relay driving switch signal. If the relay 102 is normal, it will be in an open state (open) after t22, and will cut off the power supply to the load 101.

[0029] In this state, the diagnosis unit 23 checks whether the relay 102 is in an open state, i.e., normal state (no fault) (step S21 at t23). After that, the error notification unit 21 outputs an ERROR signal that turns off the second relay drive switch signal. In response to the input of this ERROR signal, the second relay drive unit 41 turns off the second relay drive switch signal (t24). The first relay opening / closing circuit 10 stops in response to the OFF second relay drive switch signal.

[0030] Thereafter, the relay driving unit 22 turns the first relay driving switch signal ON (t25). The first relay opening / closing circuit 10 operates in response to the ON first relay driving switch signal. In this state, the diagnosing unit 23 checks whether the relay 102 is in an open state, i.e., normal state (no fault) (step S22 at t26). Thereafter, the relay driving unit 22 turns the first relay driving switch signal OFF (t27). The first relay opening / closing circuit 10 stops in response to the OFF first relay driving switch signal.

[0031] At this time, if the first relay drive switch signal is turned ON from t25 to t27, the second relay open / close circuit 30 is stopped and the relay 102 will not be closed if there is no failure in the second control unit 40 or the second relay open / close circuit 30. However, if there is a failure in the second control unit 40 or the second relay open / close circuit 30, the second relay open / close circuit 30 may be operating. In this case, if the first relay drive switch signal is turned ON, the relay 102 will be closed in the discharge holding state, which may damage the vehicle and the power source or battery (not shown) that supplies power to the load 101.

[0032] 2, in the charge / discharge control device 1 of this embodiment, when a fault diagnosis of the second control unit 40 is performed at the end of vehicle operation, the first control unit 20 first diagnoses whether the relay 102 can be opened by controlling the second relay opening / closing circuit 30. Next, the first control unit 20 diagnoses whether the relay 102 can be opened by controlling the first relay opening / closing circuit 10.

[0033] According to this configuration, when fault diagnosis of the second control unit 40 is performed while the IG is turned off (driving is terminated), even if a fault occurs in the second control unit 40 or the second relay opening / closing circuit 30, the relay 102 is prevented from inadvertently being closed and conducting current. This makes it possible to avoid damage to the vehicle, power source, or battery (not shown). Furthermore, even if a fault occurs in the second control unit 40 or the second relay opening / closing circuit 30 when fault diagnosis of the second control unit 40 is performed while the IG is turned off (driving is terminated), the delay in timing from when the IG is turned off to when the relay 102 is opened and discharged is minimized. This allows the relay 102 to be discharged quickly.

[0034] (Notification of the charge / discharge control device 1 of the embodiment) 4 is a diagram showing an example of notification by the charge / discharge control device 1 of the embodiment. For example, the display screen 500 of the notification unit 50 displays the failure diagnosis results of the second control unit 40 in the order of execution of the diagnoses after the IG is turned OFF (end of operation).

[0035] Display 510 shows the diagnostic results of S11 (FIG. 2). Display 520 shows the diagnostic results of S12 (FIG. 2).

[0036] In display 510, at the diagnosis timing of S11 (FIG. 2), IG511 is OFF, second relay drive switch signal 512 is OFF, first relay drive switch signal 513 is ON, and relay state signal 514 is Open. Display 510 shows the diagnosis result that the second relay opening / closing circuit 30 can normally open the relay 102 (relay ON / OFF 515 by second relay opening / closing circuit 30 is normal).

[0037] On the other hand, if the second control unit 40 or the second relay opening / closing circuit 30 is faulty, the second relay drive switch signal 512 remains ON after t12 (FIG. 2), and therefore the relay state signal 514 remains Closed at timing t13. Therefore, the display 510 shows the diagnosis result that the second relay opening / closing circuit 30 is in an abnormal state where the relay 102 cannot be normally opened (relay ON / OFF 515 by the second relay opening / closing circuit 30 is abnormal).

[0038] In the subsequent display 520, at the diagnosis timing of S12 (FIG. 2), IG521 is OFF, second relay drive switch signal 522 is ON, first relay drive switch signal 523 is OFF, and relay state signal 524 is Open. Display 520 shows the diagnosis result that the first relay opening / closing circuit 10 can normally open the relay 102 (relay ON / OFF 525 by the first relay opening / closing circuit 10 is normal).

[0039] On the other hand, if the second control unit 40 or the second relay opening / closing circuit 30 has failed, at t16, the second relay drive switch signal is ON, the first relay drive switch signal 523 is ON, and the relay state signal 524 is Close. Therefore, the display 520 shows the diagnosis result that an abnormal state exists in which the first relay opening / closing circuit 10 cannot normally open the relay 102 (relay ON / OFF 525 by the first relay opening / closing circuit 10 is abnormal).

[0040] (Effects of charge / discharge control device 1) The effects of the charge / discharge control device 1 will be described with reference to FIGS.

[0041] Consider a case in which the first control unit 20 opens the relay 102 when operation is terminated during the fault diagnosis of the second control unit 40. In this case, first, the second control unit 40 stops the second relay opening / closing circuit 30 (turns the second relay drive switch signal OFF) and places the relay 102 in an open state (cuts off the power supply to the load 101). Then, it is confirmed whether the relay 102 is in a normal state (no fault) in the open state (corresponding to step S11 in FIG. 2). Thereafter, the first control unit 20 stops the first relay opening / closing circuit 10 (turns the first relay drive switch signal OFF).

[0042] With this configuration, when a fault diagnosis of the second control unit 40 is performed in a state where the second relay switching circuit 30 is faulty, it is possible to prevent the relay 102 from switching from an open state to an energized state due to a fault in the second relay switching circuit 30. This makes it possible to avoid the relay 102 accidentally switching to an energized state, which could damage the vehicle, the power source, or the battery (not shown). Furthermore, it is possible to minimize the timing when the relay 102 switches to a discharged state, thereby enabling the relay 102 to be quickly discharged.

[0043] Furthermore, in the fault diagnosis of the second control unit 40, the first control unit 20 stops the first relay opening / closing circuit 10 (turns off the first relay drive switch signal), and then causes the second control unit 40 to operate the second relay opening / closing circuit 30. Then, the first control unit 20 checks whether the relay 102 is in an open state (the first control unit 20 has stopped the first relay opening / closing circuit 10) (corresponding to step S12 in FIG. 2).

[0044] With this configuration, when a fault diagnosis of the second control unit 40 is performed while the second relay switching circuit 30 is faulty, it is possible to prevent the relay 102 from inadvertently switching from an open state to a conductive state due to a fault in the second relay switching circuit 30. Furthermore, even if the second control unit 40 or the second relay switching circuit 30 is faulty, the delay in timing at which the relay 102 switches from the IG being turned OFF to the open state and then to the discharge state is kept to, for example, about 50 ms to 100 ms. This allows the relay 102 to discharge quickly.

[0045] Furthermore, if the result of the diagnosis of whether the second control unit 40 is in a state in which it can operate normally is that the relay 102 is not in a normal state (no fault) in which it is in an open state, the notification unit 50 will notify that there is a possibility of a fault in the second control unit 40 or the second relay opening / closing circuit 30.

[0046] This configuration allows the user to recognize that there is a possibility that the second control unit 40 or the second relay opening / closing circuit 30 has failed.

[0047] Furthermore, if the closed state of the relay 102 is confirmed during a first period from when the second relay switching circuit 30 is stopped until when the first relay switching circuit 10 is stopped, the notification unit 50 notifies that there is a possibility of a malfunction in the second control unit 40 or the second relay switching circuit 30. Furthermore, if the closed state of the relay 102 is confirmed during a second period after the second relay switching circuit 30 is operated again after the first relay switching circuit 10 is stopped, the notification unit 50 notifies that there is a possibility of a malfunction in the first control unit 20 or the first relay switching circuit 10.

[0048] With this configuration, the user can recognize whether the fault is in the first relay opening / closing circuit 10, the second control unit 40, or the second relay opening / closing circuit 30.

[0049] The charge / discharge control device 1 of the present invention is not limited to the configuration of the charge / discharge control device 1 described in the embodiment, and can be configured appropriately based on the contents of the claims. For example, the present invention is not limited to the charge / discharge control device 1 that controls the charge / discharge of a battery or an electricity storage element, but can also be applied to a battery control device that controls the charge / discharge of a battery or an electricity storage element, or a power supply control device that controls a power supply.

[0050] The above description is merely an example, and the present invention is not limited to the configuration of the above-described embodiment, but includes various modifications. For example, the above-described embodiment has been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to having all of the described configurations. Furthermore, the functions, processes, and configurations of the embodiment can be added, deleted, or replaced with functions, processes, and configurations of other embodiments or modifications. [Explanation of symbols]

[0051] 1 Power supply control device 10. First relay opening and closing circuit 20 First Control Section 21 Error notification section 22 Relay driver 23 Diagnostic Department 30 Second relay opening and closing circuit 40 Second Control Section 41 Second relay driver 50 Information Department 101 Load 102 Relay

Claims

1. A charge / discharge control method performed by a charge / discharge control device connected to a load via a relay, comprising: The charge / discharge control device includes: a first relay opening / closing circuit and a second relay opening / closing circuit connected in series to open and close the relay; a first control unit that controls the operation of the first relay opening / closing circuit; a second control unit that controls the operation of the second relay opening / closing circuit when failure information of the first control unit is input from the first control unit, confirming an open / closed state of the relay during a first period from when the second control unit stops the second relay open / close circuit until when the first control unit stops the first relay open / close circuit after the operation of the load has ended; When it is confirmed that the relay is in an open state during the first period, the second control unit diagnoses the relay as being in a normal state in which the relay can be set in an open state by operating the second relay open / close circuit under the control of the second control unit; If it is confirmed that the relay is in a closed state during the first period, a diagnosis is made that an abnormal state exists in which the relay cannot be brought into an open state by the operation of the second relay opening / closing circuit under the control of the second control unit. Charge and discharge control method.

2. 2. The charge / discharge control method according to claim 1, confirming the open / closed state of the relay during a second period after the first control unit has stopped the first relay open / close circuit and the second control unit has operated the second relay open / close circuit again; If it is confirmed that the relay is in an open state during the second period, the first control unit diagnoses the relay as being in a normal state in which the relay can be opened by operating the first relay opening / closing circuit, If it is confirmed that the relay is in a closed state during the second period, a diagnosis is made that an abnormal state exists in which the relay cannot be put into an open state by the operation of the first relay open / close circuit under the control of the first control unit. Charge and discharge control method.

3. 3. The charge / discharge control method according to claim 2, The charge / discharge control device has a notification unit, The notification unit, If it is confirmed that the relay is in a closed state during the first period, a notification is given that there is a possibility of a failure in the second control unit or the second relay open / close circuit. Charge and discharge control method.

4. 4. The charge / discharge control method according to claim 3, The notification unit, If it is confirmed that the relay is in a closed state during the second period, a notification is given that there is a possibility of a failure in the first control unit or the first relay opening / closing circuit. Charge and discharge control method.

5. A charge / discharge control device connected to a load via a relay, a first relay opening / closing circuit and a second relay opening / closing circuit connected in series to open and close the relay; a first control unit that controls the operation of the first relay opening / closing circuit; a second control unit that controls the operation of the second relay opening / closing circuit when failure information of the first control unit is input from the first control unit, The first control unit confirming an open / closed state of the relay during a first period from when the second control unit stops the second relay open / close circuit until when the first control unit stops the first relay open / close circuit after the operation of the load has ended; When it is confirmed that the relay is in an open state during the first period, the second control unit diagnoses the relay as being in a normal state in which the relay can be set in an open state by operating the second relay open / close circuit under the control of the second control unit; If it is confirmed that the relay is in a closed state during the first period, a diagnosis is made that an abnormal state exists in which the relay cannot be brought into an open state by the operation of the second relay opening / closing circuit under the control of the second control unit. Charge and discharge control device.

6. The charge / discharge control device according to claim 5, confirming the open / closed state of the relay during a second period after the first control unit has stopped the first relay open / close circuit and the second control unit has operated the second relay open / close circuit again; If it is confirmed that the relay is in an open state during the second period, the first control unit diagnoses the relay as being in a normal state in which the relay can be opened by operating the first relay opening / closing circuit, If it is confirmed that the relay is in a closed state during the second period, a diagnosis is made that an abnormal state exists in which the relay cannot be put into an open state by the operation of the first relay open / close circuit under the control of the first control unit. Charge and discharge control device.

7. The charge / discharge control device according to claim 6, a notification unit that notifies the user that there is a possibility of a failure in the second control unit or the second relay open / close circuit when it is confirmed that the relay is in a closed state during the first period; Charge and discharge control device.

8. The charge / discharge control device according to claim 7, The notification unit If it is confirmed that the relay is in a closed state during the second period, a notification is given that there is a possibility of a failure in the first control unit or the first relay opening / closing circuit. Charge and discharge control device.

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