JP2010252475A - Power supply device system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suitably perform the detection of the overvoltage state of a power accumulation device and the determination of the fusion of relay circuits, in a power supply device system. <P>SOLUTION: The power supply device system 10 includes: the power accumulation device 12; a capacitor 40 arranged between a positive electrode side line 50 and a negative electrode side line 52; the first relay circuit 16, the second relay circuit 20, and the third relay circuit 23 which operate on the basis of system start signals from the outside; and a control part which performs fusion determination processing for determining whether the first relay circuit 16, the second relay circuit 20, and the third relay circuit 23 are in normal blocked states or in fused states by discharging the electricity of the capacitor 40 after the completion of the monitoring of an overvoltage of the power accumulation device 12 in a period that blocking commands are effective in the first relay circuit 16, the second relay circuit 20, and the third relay circuit 23 after the acquisition of the system start signals. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply system, and more particularly to a power supply system having a relay circuit unit.

  In a power supply system including a power storage device mounted on a vehicle such as an electric vehicle or a hybrid vehicle, it is necessary to monitor a power storage state of the power storage device. For example, whether the power storage device is in an overvoltage state. Need to be monitored. In such a power supply system, a relay circuit unit may be provided between the power storage device and the load circuit connected to the load, and it is determined whether or not the relay circuit unit is welded. There are things to do.

  As a technique for determining whether or not the relay circuit unit is welded, for example, in Patent Document 1, as a welding detection device for a relay circuit unit connected to a battery, with the relay circuit unit turned off, It is described that the switching element of the inverter is controlled to start discharging the electric charge stored in the capacitor. In addition, it is described that after a time when the discharge of the normal capacitor ends is elapsed, the current of each phase of the motor is detected by an ammeter and it is determined whether the current is in the vicinity of the value 0. Further, it is described that when the current is not in the vicinity of the value 0, it is determined that the relay circuit unit is welded and the LED is turned on.

Further, as another technique for determining whether or not the relay circuit unit is welded, for example, in Patent Document 2, as a power supply control device having a relay circuit unit connected to a DC power supply, the control device is a vehicle. When the precharge current Ip when the H level signal SEB is generated at the time of starting the system and only the relay circuit unit SMRB is turned on is greater than or equal to the reference value Istd, it is determined that the relay circuit unit SMRP is welded. It is stated. When the control device determines that the relay circuit unit SMRP is welded, the controller immediately turns off the relay circuit unit SMRB without discharging the relay circuit units SMRG and SMRB and discharges the capacitor. It has been. At this time, it is described that the control device determines the welding of the relay circuit unit SMRB based on the voltage (V _H ) across the capacitor.

JP 2000-270561 A JP 2006-320079 A

  In the above-mentioned Patent Document 1, the charge accumulated in the capacitor is discharged and the welding of the relay circuit unit is determined by the current of each phase of the motor. However, the detection of the overvoltage state of the battery is also disclosed. Absent. For this reason, when the discharge of the electric charge stored in the capacitor is performed for the determination of the welding of the relay circuit unit and the overvoltage state of the battery is detected, for example, when the relay circuit unit is welded, In some cases, the battery cannot be discharged and the overvoltage state of the battery cannot be detected.

In Patent Document 2, the capacitor is discharged and the welding of the relay circuit unit is determined based on the voltage V _H across the capacitor. However, the detection of the overvoltage state of the DC power supply is also disclosed. It has not been. For this reason, the capacitor is discharged to determine whether or not the relay circuit unit is welded, and if the overvoltage state of the DC power supply is detected, for example, when the relay circuit unit is welded, the capacitor cannot be discharged. In some cases, the overvoltage state of the DC power supply cannot be detected.

  An object of the present invention is to provide a power supply device system that can more suitably perform determination of welding of a relay circuit unit together with detection of an overvoltage state of a power storage device.

  A power supply device system according to the present invention is provided between a power storage device, a capacitor provided between a positive electrode side line and a negative electrode side line of a load circuit connected to a load, and between the power storage device and the load circuit. The relay circuit that operates based on the system start signal from and the period when the relay circuit unit is instructed to shut off when the capacitor has a charge to be discharged after acquiring the system start signal from the outside. And a control unit that performs welding determination processing to determine whether the relay circuit unit is in a normal cut-off state or is welded after the monitoring of the overvoltage of the power storage device is completed.

  Further, in the power supply system according to the present invention, the control unit determines whether or not an external system activation signal has been acquired, and after acquiring the external system activation signal, the relay circuit unit Monitoring process completion judgment for judging whether or not the monitoring process for monitoring whether or not the voltage across the power storage device is in an overvoltage state exceeding a predetermined threshold value during the period in which the shutdown instruction is made is completed Means, after completing the monitoring process of the power storage device, instructing the discharge process to discharge the capacitor within the period when the disconnection instruction is made to the relay circuit unit, whether or not the voltage across the capacitor decreases, Welding determination means for performing welding determination processing to determine whether the relay circuit section is in a normal shut-off state or welding; and connection instruction means for instructing connection to the relay circuit section after completion of the welding determination processing Preferably it has a.

  Moreover, in the power supply device system according to the present invention, the monitoring process completion judging means determines that the voltage across the power storage device exceeds the predetermined threshold value to determine an overvoltage state, or a preset monitoring period. It is preferable to determine that the monitoring process is completed when elapses.

  Further, in the power supply system according to the present invention, the control unit has means for acquiring the voltage across the capacitor, and when the voltage across the capacitor exceeds a predetermined value, the charge to be discharged to the capacitor is It is preferable to determine that there is.

  In the power supply device system according to the present invention, the power storage device is preferably a lithium ion secondary battery.

  According to the power supply device system configured as described above, after the monitoring of the overvoltage state of the power storage device is completed, the capacitor is discharged, and a welding determination process is performed to determine whether the relay circuit unit is in a normal shut-off state or welded. Thereby, even if the relay circuit unit is welded, the overvoltage state of the power storage device can be detected more accurately. Therefore, it is possible to more suitably determine the welding of the relay circuit together with the detection of the overvoltage state of the power storage device.

In embodiment which concerns on this invention, it is a figure which shows a power supply device system. In embodiment which concerns on this invention, it is a figure which shows each element of the control part of a power supply device system. In embodiment concerning this invention, it is a timing chart of each signal, such as a system starting signal, in a power supply device system. 4 is a flowchart showing the operation of the power supply system in the embodiment according to the present invention.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. In the following description, the power supply device system is described as being mounted on a hybrid vehicle, but may be mounted on an electric vehicle.

  Below, the same code | symbol is attached | subjected to the same element in all the drawings, and the overlapping description is abbreviate | omitted. In the description in the text, the symbols described before are used as necessary.

  FIG. 1 is a diagram showing a power supply system 10. The power supply device system 10 includes a power supply device 100 and a control unit 110. First motor generator 60 and second motor generator 70 are driven by power supply device 100. Hereinafter, the power supply apparatus 100 will be described, and the first motor generator 60, the second motor generator 70, and the control unit 110 will be described in this order. In the following description, it is assumed that the power supply system 10 is mounted on a hybrid vehicle that is activated by IG-ON (ignition on).

  The power supply device 100 includes a power storage device 12, a current sensor 14, a first relay circuit unit 16, a second relay circuit unit 20, a third relay circuit unit 23, capacitors 28 and 40, and a step-up / down converter circuit 39. And a first inverter circuit 200 and a second inverter circuit 300.

  The power storage device 12 is a battery for supplying power to the first motor generator 60 and the second motor generator 70. The power storage device 12 is a chargeable / dischargeable DC power source, for example, a negative electrode composed of a carbon material, an electrolyte for moving lithium ions, and a positive electrode active material capable of reversing lithium ions. Can be used.

The current sensor 14 is a current sensor that is connected in series to one terminal of the power storage device 12 and measures a current value flowing to the power storage device 12. Note that although the current value flowing to the power storage device 12 is described as being measured using the current sensor 14, the total power value for the circuit driven by the power storage device 12 of the power supply device system 10 is expressed at both ends of the capacitor 28. You may obtain | require and estimate from the value divided by the voltage _VL .

  The first relay circuit unit 16 is a relay connected in series to the current sensor 14, and connection or disconnection control is performed by a control command from the control unit 110. The second relay circuit unit 20 is configured by connecting in series a resistance element 22 and a relay 18 that is controlled to be connected or disconnected according to a control command from the control unit 110. Second relay circuit unit 20 is connected in series to the other terminal of power storage device 12. The third relay circuit unit 23 is a relay connected in parallel to the second relay circuit unit 20, and connection or disconnection control is performed by a control command from the control unit 110.

  Here, a state in which the power storage device 12 and the load circuit connected to the positive electrode side line 24 and the negative electrode side line 26 are connected is referred to as SMR connection, and the power storage device 12 and the load circuit are disconnected from each other. Is called SMR opening. SMR connection means that the relay of the first relay circuit unit 16 is in a connected state and at least one of the relay 18 of the second relay circuit unit 20 and the relay of the third relay circuit unit 23 is in a connected state. Say. Moreover, SMR opening means that the relay of the 1st relay circuit part 16 is a cutoff state, and the relay 18 of the 2nd relay circuit part 20 and the relay of the 3rd relay circuit part 23 are a cutoff state. In the SMR opening, when the relay of the first relay circuit unit 16 is in the cutoff state, the relay 18 of the second relay circuit unit 20 and the relay of the third relay circuit unit 23 may not be in the cutoff state. Even if the relay of the 1st relay circuit part 16 is not a cutoff state, the relay 18 of the 2nd relay circuit part 20 and the relay of the 3rd relay circuit part 23 should just be a cutoff state.

  Although the SMR release instruction is issued, the relay of the first relay circuit unit 16 is welded and connected, and further, the relay 18 of the second relay circuit unit 20 and the relay of the third relay circuit unit 23 are connected. It is called SMR bipolar welding that at least one of them is welded and connected.

The capacitor 28 is a smoothing capacitor that is connected between the positive electrode side line 24 and the negative electrode side line 26 and smoothes voltage fluctuations between the positive electrode side line 24 and the negative electrode side line 26. Here, the voltage across the capacitor 28 is assumed to be V _L.

  The step-up / down converter circuit 39 includes a coil 30 connected in series with the positive electrode side line 24, a transistor 32 connected between the coil 30 and the positive electrode side line 50, and a coil 30 and a negative electrode side line 52. It includes a transistor 34 connected, a diode 36 connected in parallel to the transistor 32, and a diode 38 connected in parallel to the transistor 34.

  The buck-boost converter circuit 39 has a function of boosting the DC voltage received from the power storage device 12 using the coil 30. Specifically, the step-up / step-down converter circuit 39 accumulates current flowing in accordance with the switching operation of the transistor 34 as electromagnetic energy in the coil 30. The step-up / down converter circuit 39 boosts the accumulated electromagnetic energy in the capacitor 40 via the diode 36 in synchronization with the timing when the transistor 34 is turned off.

  Further, the step-up / down converter circuit 39 steps down the DC voltage received from the first inverter circuit 200 or the second inverter circuit 300 and charges the power storage device 12.

The capacitor 40 is connected between the positive electrode side line 50 and the negative electrode side line 52, and is a smoothing capacitor that smoothes voltage fluctuations between the positive electrode side line 50 and the negative electrode side line 52. Here, the voltage across the capacitor 40 is V _H.

  The first inverter circuit 200 and the second inverter circuit 300 convert the DC voltage of the capacitor 40 into an AC voltage during powering and supply the AC voltage to the first motor generator 60 or the second motor generator 70, whereby the first motor generator 60 or Second motor generator 70 is driven to rotate. In addition, the first inverter circuit 200 and the second inverter circuit 300 convert the AC voltage generated by the first motor generator 60 or the second motor generator 70 into a DC voltage during regeneration and supply it to the power storage device 12. The power storage device 12 is charged.

  As a component of the first inverter circuit 200, a transistor 210 and a transistor 220 are connected in series between the positive electrode side line 50 and the negative electrode side line 52. In addition, a diode 212 is connected in parallel to the transistor 210, and a diode 222 is connected in parallel to the transistor 220.

  As another component of the first inverter circuit 200, a transistor 230 and a transistor 240 are connected in series between the positive line 50 and the negative line 52. A diode 232 is connected in parallel to the transistor 230, and a diode 242 is connected in parallel to the transistor 240.

  As yet another component of the first inverter circuit 200, a transistor 250 and a transistor 260 are connected in series between the positive electrode side line 50 and the negative electrode side line 52. A diode 252 is connected in parallel to the transistor 250, and a diode 262 is connected in parallel to the transistor 260. Note that, as shown in FIG. 1, the second inverter circuit 300 is also composed of the same elements as the first inverter circuit 200, and thus detailed description thereof is omitted.

  First motor generator 60 and second motor generator 70 are loads connected to power supply device 100. First motor generator 60 includes a U-phase coil 62, a V-phase coil 64, and a W-phase coil 66. U-phase coil 62 is a coil connected between a connection point between transistor 210 and transistor 220 and neutral point 68. V-phase coil 64 is a coil connected between a connection point between transistor 230 and transistor 240 and neutral point 68. W-phase coil 66 is a coil connected between a connection point between transistor 250 and transistor 260 and neutral point 68. As shown in FIG. 1, the second motor generator 70 is configured by the same elements as the first motor generator 60, and thus detailed description thereof is omitted.

  Next, the control unit 110 will be described. FIG. 2 is a diagram illustrating each element of the control unit 110. The control unit 110 is a control device that controls the power supply device 100 in the power supply device system 10. For example, the control unit 110 performs switching control of each transistor of the buck-boost converter circuit 39, the first inverter circuit 200, and the second inverter circuit 300. Here, in particular, control unit 110 determines the welding of first relay circuit unit 16, second relay circuit unit 20, and third relay circuit unit 23 together with detection of an overvoltage state of power storage device 12 of power supply system 10. The function will be described.

  The control unit 110 includes an activation signal determination I / F 132, a monitoring process completion determination I / F 134, a welding determination I / F 136, a connection instruction I / F 138, a storage unit 130, and a CPU 120. Each element is connected to each other through an internal bus. As the control unit 110, a computer suitable for the power supply system 10 can be used.

  The activation signal determination I / F 132 is an interface circuit connected to a generation circuit unit (not shown) that generates a system activation signal when the hybrid vehicle is IG-ON (ignition-on). The monitoring process completion determination I / F 134 is an interface circuit connected to the power storage device 12. The welding determination I / F 136 is an interface circuit connected to the capacitor 40. The connection instruction I / F 138 is an interface circuit connected to the first relay circuit unit 16, the second relay circuit unit 20, and the third relay circuit unit 23.

  The CPU 120 includes an activation signal determination processing unit 122, a monitoring processing completion determination processing unit 124, a welding determination processing unit 126, and a connection instruction processing unit 128. Each of these functions can be realized by executing software, specifically, by executing a welding determination program stored in the storage unit 130. Further, some of these functions may be realized as hardware.

  The activation signal determination processing unit 122 has a function of determining whether or not a system activation signal generated when an IG-ON (ignition on) of the hybrid vehicle is performed is acquired via the activation signal determination I / F 132.

  After obtaining the system activation signal, the monitoring process completion determination processing unit 124 issues a cutoff instruction (SMR opening instruction) to the first relay circuit unit 16, the second relay circuit unit 20, and the third relay circuit unit 23. During the period, the monitoring process of the power storage device 12 and whether or not the monitoring process is completed are determined. Specifically, the monitoring process completion determination processing unit 124 acquires information on the power storage device 12 via the monitoring process completion determination I / F 134, and based on the information, the voltage across the power storage device 12 is set to a predetermined value. It has a function of monitoring and determining whether or not an overvoltage state exceeding the threshold value is reached, and further determining whether or not the monitoring process of the power storage device 12 is completed. Here, the case where the monitoring process of the power storage device 12 is completed means that the power storage device 12 is determined to be in an overvoltage state or a preset monitoring period has elapsed.

After the monitoring process of the power storage device 12 is completed, the welding determination processing unit 126 issues a disconnection instruction (SMR release instruction) to the first relay circuit unit 16, the second relay circuit unit 20, and the third relay circuit unit 23. The welding determination process is performed within a certain period. Specifically, the welding determination process of the welding determination processing unit 126 determines whether or not the capacitor 40 has a charge to be discharged. If the capacitor 40 has a charge to be discharged, the capacitor 40 is discharged. The first relay circuit unit 16, the second relay circuit unit 20, and the third relay circuit unit 23 are instructed depending on whether or not the voltage (V _H ) across the capacitor 40 after discharging has decreased to a predetermined voltage. Is a process for determining whether or not a normal shut-off state or SMR bipolar welding. Here, when the voltage (V _H ) across the capacitor 40 exceeds a predetermined value V _th , it is determined that the capacitor 40 has a charge to be discharged.

  When the welding determination processing unit 126 determines that the first relay circuit unit 16, the second relay circuit unit 20, and the third relay circuit unit 23 are in a normal cutoff state, the connection instruction processing unit 128 The first relay circuit unit 16, the second relay circuit unit 20, and the third relay circuit unit 23 have a function of giving a connection instruction (SMR connection instruction) via a connection instruction I / F 138.

  FIG. 3 is a timing chart of each signal such as a system activation signal in the power supply system 10. Each signal in FIG. 3 is a signal output by the control unit 110. The IG signal is a signal for starting up the power supply system 10. When an IG-ON (ignition on) is performed by an external operation of a user or the like and a system start signal is received, the IG signal is switched from Low (OFF) to High ( ON).

The rdywait signal changes from Low to High when the IG signal becomes High, and the power storage device 12 is determined to be in an overvoltage state, or a preset monitoring period has elapsed since the rise of the rdywait signal. The signal changes from High to Low. The inverter voltage signal is a voltage value indicated by the voltage across the capacitor 40 (V _H ).

  The discharge processing request flag signal is a signal for requesting to discharge the capacitor 40 by changing from Low to High when the rdywait signal changes from High to Low. The discharge processing request flag signal is a signal that changes from Low to High, and changes from High to Low again after the discharge processing of the capacitor 40 is performed and the determination of SMR welding detection is completed.

  The cell overvoltage detection signal is a signal that changes from Low to High when it is detected that the power storage device 12 is in an overvoltage state.

  The SMR bipolar welding detection signal is a signal that changes from Low to High when it is detected that the first relay circuit unit 16, the second relay circuit unit 20, and the third relay circuit unit 23 are SMR bipolar welding. is there.

Next, the flow of the timing chart of FIG. 3 will be described. When the IG-ON is performed by an external operation by the user or the like (time A in FIG. 3), the IG signal changes from Low to High. When the IG-ON is performed, the rdywait signal changes from Low to High in synchronization (time A in FIG. 3). Further, in synchronization with IG-ON (time A in FIG. 3), the value of the voltage (V _H ) across the capacitor 40, which is the inverter voltage, is output.

  As described above, the rdywait signal changes from High to Low when the power storage device 12 is determined to be in an overvoltage state or when a preset monitoring period has elapsed. In the example shown in FIG. 3, when the power storage device 12 is in an overvoltage state and the cell overvoltage detection signal detects an overvoltage of the power storage device 12 (time B in FIG. 3), it changes from Low to High, and rdywait The signal changes from High to Low at the same time B. Then, the discharge processing request flag signal changes from Low to High in synchronization with the falling edge of the rdywait signal (time B in FIG. 3). Further, the discharging process of the capacitor 40 is performed from the point B in FIG. In the example shown in FIG. 3, since the first relay circuit unit 16, the second relay circuit unit 20, and the third relay circuit unit 23 are SMR bipolar welding, the inverter voltage signal is as shown in FIG. In addition, after the capacitor 40 is discharged and once lowered after the time point B, the electric power is replenished from the power storage device 12, so that the voltage returns to the original voltage again.

  The discharge processing request flag signal changes from High to Low when the discharge processing of the capacitor 40 is performed and the determination of SMR welding detection is completed. In the example shown in FIG. 3, since the SMR welding determination is completed at time C, the discharge processing request flag signal changes from High to Low. Further, here, since the first relay circuit unit 16, the second relay circuit unit 20, and the third relay circuit unit 23 are SMR bipolar welding, the SMR bipolar welding detection signal changes from Low to High at time C. ing.

  Next, the operation of the power supply system 10 having the above configuration will be described with reference to FIGS. FIG. 4 is a flowchart showing the operation of the power supply system 10. The control unit 110 determines whether there is a system activation signal of the power supply system 10 from a user or the like outside. Specifically, it is determined whether or not the IG signal is High (ON) (S10). Step S10 is executed by the function of the activation signal determination processing unit 122 of the CPU 120. If it is determined in S10 that the IG signal is Low (OFF), the process proceeds to return processing.

If it is determined in S10 that the IG signal is High, it is determined whether or not the voltage (V _H ) across the capacitor 40, which is an inverter voltage, exceeds a predetermined voltage (V _th ) (S12). . The process of S12 is executed by the function of the welding determination processing unit 126 of the CPU 120. If it is determined in S12 that the inverter voltage does not exceed the predetermined voltage (V _th ), the process proceeds to return processing.

If it is determined that the inverter voltage exceeds the predetermined voltage (V _th ), it is determined that there is a charge to be discharged in the capacitor 40, and the process proceeds to S14. In S14, it is determined whether or not the monitoring process of the power storage device 12 is completed. Specifically, it is determined whether or not the rdywait signal has changed from High to Low (S14). The process of S14 is executed by the function of the monitoring process completion determination processing unit 124 of the CPU 120. In S14, when it is determined that the monitoring process of the power storage device 12 is not completed, the process proceeds to a return process. Here, when it is determined that the power storage device 12 is in an overvoltage state, the cell overvoltage signal changes from Low to High.

In S14, when it is determined that the monitoring process of the power storage device 12 has been completed, the discharge process request flag signal changes from Low to High, the charge accumulated in the capacitor 40 is discharged, and both ends of the capacitor 40 are discharged. A drop state of the voltage (V _H ) is monitored (S16). The process of S16 is executed by the function of the welding determination processing unit 126 of the CPU 120.

Next, it is determined whether or not the first relay circuit unit 16, the second relay circuit unit 20, and the third relay circuit unit 23 are SMR bipolar welding (S18). The process of S18 is executed by the function of the welding determination processing unit 126 of the CPU 120. If it is determined in S18 that SMR bipolar welding is performed, the process proceeds to return processing. Here, when the voltage (V _H ) after discharging the capacitor 40 has not decreased to a predetermined value, it is determined that SMR bipolar welding has occurred, and the voltage (V _H ) has decreased to a predetermined value. Is determined to be a normal SMR release state. When it is determined that the SMR bipolar welding is performed, the SMR bipolar welding detection signal changes from Low to High.

  If it is determined in S18 that SMR bipolar welding has not been performed, a connection instruction (SMR connection instruction) is issued to the first relay circuit unit 16, the second relay circuit unit 20, and the third relay circuit unit 23. (S20). After S20 is performed, an END process (not shown) is executed. As described above, according to the power supply device system 10, after monitoring of the overvoltage state of the power storage device 12 is completed, the capacitor 40 is discharged to determine SMR bipolar welding. Thus, even when the SMR bipolar welding is performed and the capacitor 40 is discharged and the voltage state of the power storage device 12 decreases, the overvoltage state monitoring is not affected. Therefore, it is possible to more suitably determine the welding of the relay circuit together with the detection of the overvoltage state of the power storage device.

  DESCRIPTION OF SYMBOLS 10 Power supply system, 12 Power storage device, 14 Current sensor, 16 1st relay circuit part, 18 Relay, 20 2nd relay circuit part, 22 Resistance element, 23 3rd relay circuit part, 24, 50 Positive side line, 26, 52 Negative side line, 28, 40 capacitor, 30 coil, 32, 34 transistor, 36, 38 diode, 39 Buck-boost converter circuit, 40 capacitor, 60 1st motor generator, 62 U phase coil, 64 V phase coil, 66 W Phase coil, 68 Neutral point, 70 Second motor generator, 100 Power supply device, 110 Control unit, 120 CPU, 122 Activation signal determination processing unit, 124 Monitoring processing completion determination processing unit, 126 Welding determination processing unit, 128 Connection instruction processing Section, 130 storage section, 200 first inverter circuit, 210, 22 , 230, 240, 250, 260 transistor, 212,222,232,242,252,262 diode, 300 an inverter circuit.

Claims (5)

A power storage device;
A capacitor provided between the positive electrode side line and the negative electrode side line of the load circuit connected to the load;
A relay circuit unit that is provided between the power storage device and the load circuit and operates based on a system start signal from the outside;
After acquiring the system activation signal from the outside, if there is a charge to be discharged to the capacitor, the capacitor is turned on after the monitoring of the overvoltage of the power storage device is completed within the period when the relay circuit unit is instructed to shut off. A control unit that performs welding determination processing to determine whether the relay circuit unit is normally disconnected or welded by discharging;
A power supply system comprising: The power supply system according to claim 1,
The control unit
An activation signal determination means for determining whether or not an external system activation signal has been acquired;
Monitoring that monitors whether or not the voltage across the power storage device exceeds a predetermined threshold value during a period when the relay circuit unit is instructed to shut off after acquiring an external system activation signal Monitoring process completion judging means for judging whether or not processing is completed;
After the storage device monitoring process is completed, the relay circuit unit is instructed to perform a discharge process for discharging the capacitor within a period in which the relay instruction is given to the relay circuit unit. Welding determination means for performing a welding determination process as to whether the welding is in a normal shut-off state or welding,
Connection instructing means for instructing connection to the relay circuit unit after completion of the welding determination process;
A power supply system comprising: The power supply system according to claim 2,
The monitoring process completion determining means is configured to complete the monitoring process when it is determined that the voltage across the power storage device exceeds a predetermined threshold value to determine an overvoltage state or when a preset monitoring period has elapsed. It is determined that the power supply system. In the power supply system according to any one of claims 1 to 3,
The control unit
Having means for obtaining the voltage across the capacitor;
A power supply system characterized by determining that there is a charge to be discharged to a capacitor when the voltage across the capacitor exceeds a predetermined value. The power supply system according to any one of claims 1 to 4,
The power storage device is a lithium ion secondary battery.

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