Method for controlling a power supply system of a mobile body, a power supply system of a mobile body, and a power storage device

Abstract

To reduce a risk that power supply to a mobile body is stopped even if all power storage devices that are connected in parallel malfunction.SOLUTION: A control method for a power supply system 30 of a vehicle 10 includes: a first step of permitting or prohibiting interruption of current in each of power storage device 50 on the basis of a normality / abnormality combination of the power storage devices 50 such that a current interruption device 53 for at least one power storage devices 50 is in a powered state; and a second step of bringing the current interruption device 53 into an interrupted state in a case where a BMU 100 of the power storage device 50 for which current interruption has been permitted has detected an abnormality in the power storage device 50 at the time point of the permission of current interruption or in a case where the BMU 100 detects an abnormality in the power storage device 50 after the permission of current interruption.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a control method for a power supply system of a mobile body, a power supply system of a mobile body, and a power storage device. [Background technology]

[0002] Currently, vehicle manufacturers are actively developing automatic braking systems and automatic driving technologies. This trend toward electrification of vehicles (mobiles) is further increasing the importance of vehicle power systems. Currently, the mainstream vehicle power system is one that supplies power using a single power storage device and an alternator. If the power storage device suddenly breaks down or if the harness connected to the external terminal of the power storage device becomes disconnected, the power supply to the vehicle may be cut off, so there has been a demand for connecting two power storage devices in parallel to provide redundancy. The following document 1 describes that a vehicle power supply device is configured to include a control device, an electric load, a main relay, a starter, an alternator, a lead-acid battery, a nickel-metal hydride rechargeable battery, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-67042 A Summary of the Invention [Problem to be solved by the invention]

[0004] To ensure safety, some power storage devices are equipped with a current interruption device that cuts off the current when an abnormality such as overcharging occurs. For example, in a power supply system in which two power storage devices are connected in parallel, if one of the two power storage devices experiences an abnormality, even if the current to one of the two power storage devices is cut off, the other power storage device can continue to supply power to the vehicle. However, if the current is cut off when the other power storage device becomes abnormal, both power storage devices will be cut off and power will no longer be supplied to the mobile load. For this reason, there is room for improvement in reducing the risk of power being cut off to the mobile load.

[0005] This specification discloses a technique that can reduce the risk of power not being supplied to a mobile load even if all of a plurality of power storage devices connected in parallel become abnormal. [Means for solving the problem]

[0006] A control method for a power supply system of a mobile body, the power supply system including a plurality of power storage devices connected to a mobile body load and connected in parallel with each other, the power storage devices including a power storage element, a current interruption device connected in series with the power storage element, and a management device, the control method including: a first step of permitting or prohibiting current interruption for each of the power storage devices based on a combination of normality and abnormality of each of the power storage devices so that the current interruption device of at least one of the power storage devices is in an energized state; and a second step of setting the current interruption device to an interrupted state when the management device of the power storage device permitted to interrupt the current detects an abnormality in the power storage device at the time when current interruption is permitted, or when an abnormality in the power storage device is detected after current interruption is permitted. Effect of the Invention

[0007] This reduces the risk of power not being supplied to the mobile load even if all of the multiple power storage devices connected in parallel experience an abnormality. [Brief description of the drawings]

[0008] [Figure 1] Schematic diagram of a vehicle according to embodiment 1. [Diagram 2] Power System Block Diagram [Diagram 3] Block diagram of a first power storage device [Figure 4] Exploded perspective view of the power storage device [Figure 5A] Plan view of secondary battery [Figure 5B] Cross-sectional view of line AA in Figure 5A [Figure 6] Block diagram of a second power storage device [Figure 7] Charging curve chart [Figure 8] Power system control process sequence [Figure 9] Power system control process sequence [Figure 10] Power system control process sequence [Figure 11] Sequence of control process of power supply system according to embodiment 2 [Figure 12] Power system control process sequence [Figure 13] Power system control process sequence [Figure 14] Block diagram of a power supply system according to a third embodiment. [Figure 15] Sequence of control process of power supply system according to embodiment 4 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (Outline of this embodiment) (1) A control method for a power supply system of a mobile body, the power supply system including a plurality of power storage devices connected to a mobile body load and connected in parallel with each other, the power storage devices including a power storage element, a current interruption device connected in series with the power storage element, and a management device, the control method including: a first step of permitting or prohibiting current interruption for each of the power storage devices based on a combination of normality and abnormality of each of the power storage devices so that the current interruption device of at least one of the power storage devices is in a conducting state; and a second step of setting the current interruption device to a cut-off state when the management device of the power storage device permitted to interrupt the current detects an abnormality in the power storage device at the time when current interruption is permitted, or when the management device detects an abnormality in the power storage device after current interruption is permitted.

[0010] The above "abnormality" is not limited to a case where the power storage device has already reached an abnormal state, but also includes a case where it is predicted that the power storage device will reach an abnormal state. In the above control method, the conventional idea of ​​ensuring the safety of the power storage devices by current interruption is reversed, and current interruption is permitted or prohibited for each power storage device based on a combination of normal and abnormal states of each power storage device so that the current interruption device of at least one power storage device is in a conducting state, and the management device of the power storage device permitted to interrupt the current sets the current interruption device to the interrupted state when the management device of the power storage device permitted to interrupt the current detects an abnormality in the power storage device at the time when current interruption is permitted, or when an abnormality in the power storage device is detected after current interruption is permitted. Since the current interruption device of the power storage device permitted to interrupt the current is set to the interrupted state, the power storage device permitted to interrupt the current can be protected from abnormalities. Even if all the power storage devices become abnormal, at least one power storage device will be connected to the mobile body, so the risk of power not being supplied to the mobile body load can be reduced compared to the case where none of the power storage devices are connected to the mobile body.

[0011] (2) The abnormality in the power storage device may include an abnormality in the management device.

[0012] Abnormalities in the power storage device include abnormalities in the power storage elements and abnormalities in the management device. If the management device becomes abnormal, it may not be able to correctly detect the state of the power storage device, and may determine that there is an abnormality in the power storage device even though there is no abnormality, and may cut off the current. For this reason, in a conventional power supply system equipped with only one power storage device, the risk of power not being supplied to the mobile load is reduced by prohibiting current cut-off when an abnormality occurs in the management device. However, if current cut-off is prohibited, the current will not be cut off even if an abnormality occurs in the power storage element after that, and there is a possibility that the safety of the power storage device cannot be ensured.

[0013] The present inventors have discovered that in a power supply system with redundancy, even if an abnormality occurs in the management device of a certain storage device, if there is another storage device that is functioning normally, the current to the storage device whose management device has the abnormality can be cut off, thereby reducing the risk of power being cut off to the mobile load, while ensuring the safety of the storage device whose management device has the abnormality. According to the above control method, if an abnormality occurs in the management device of a certain energy storage device and there is another normal energy storage device, the management device allows the current to be cut off to the energy storage device with the abnormality and prohibits the current from being cut off to the normal energy storage devices, thereby ensuring the safety of the energy storage device with the abnormality in the management device while reducing the risk of power being cut off to the mobile load.

[0014] (3) The abnormality in the power storage device may be an abnormality in the management device.

[0015] The present inventors have discovered that in a power supply system with redundancy, even if an abnormality occurs in the management device of one storage device, if there is another storage device with a normal management device, the current to the storage device with the abnormal management device can be cut off, thereby reducing the risk of power being cut off to the mobile load, while ensuring the safety of the storage device with the abnormal management device.

[0016] According to the above control method, if an abnormality occurs in the management device of a certain energy storage device, and there is another energy storage device whose management device is normal, the management device will allow the current to be cut off to the energy storage device whose abnormality occurred, and will prohibit the current from being cut off to the energy storage device whose management device is normal, thereby ensuring the safety of the energy storage device whose management device has an abnormality while reducing the risk of power being cut off to the mobile load.

[0017] (4) The first step may include the steps of prohibiting each of the storage devices from cutting off current when all of the storage devices are normal; requesting permission to cut off current when the management device of the storage devices detects an abnormality in the storage device; and, when permission to cut off current is requested from the management device, permitting or prohibiting the storage devices that have requested permission to cut off current to cut off current, based on a combination of normality and abnormality of the storage devices, so that the current cut-off device of at least one of the storage devices is in an energized state.

[0018] A possible configuration of the power supply system of the mobile body is that the control unit and the power storage devices provided in the mobile body are connected to be able to communicate with each other, and the control unit allows or prohibits the power storage devices from cutting off current. A possible control method in this case is that the control unit allows each power storage device to cut off current when all the power storage devices are normal, and the management device cuts off the current when an abnormality occurs in the power storage device. However, with this control method, if some kind of failure occurs and communication between the control unit and the power storage devices is cut off, the power storage devices cannot be prohibited from cutting off current even when it is necessary to do so, and the current may be cut off, resulting in no power being supplied to the mobile body load.

[0019] According to the above control method, when all the power storage devices are normal, current interruption is prohibited for each power storage device. In this way, if communication between the control unit and the power storage devices is subsequently cut off, the control unit will not permit current interruption even if an abnormality occurs in the power storage device, so the power storage device will remain prohibited from current interruption. This reduces the risk that power will not be supplied to the mobile load even if communication between the control unit and the power storage devices is cut off. The above control method is particularly useful in the case of a power supply system in which it is strongly desired to reduce the risk that power will not be supplied to the mobile load. Here, we have shown an example of a case where a control unit equipped in a mobile body allows or prohibits each storage device from cutting off current, but the configuration may also be such that a management device for any one of the multiple storage devices functions as the control unit described above.

[0020] (5) The first step may include a step of permitting current interruption to all of the power storage devices when two or more of the power storage devices are normal, and a step of prohibiting current interruption to the normal power storage device when the number of normal power storage devices is one.

[0021] According to the above control method, when the number of normal power storage devices is two or more, current cut-off is permitted for all power storage devices, so that the current is cut off for an abnormal power storage device, and the current is cut off for a normal power storage device when it subsequently becomes abnormal, thereby ensuring the safety of the power storage devices. For example, if two power storage devices are normal and one of the power storage devices subsequently becomes abnormal, only one power storage device remains normal. When only one power storage device remains normal, current cutoff for that power storage device is prohibited, thereby reducing the risk of power not being supplied to the mobile load.

[0022] (6) In the first step, when all of the power storage devices are abnormal, current cutoff may be prohibited for two or more of the power storage devices.

[0023] If all the storage devices are abnormal, prohibiting current cutoff for at least one storage device can prevent power from being supplied to the mobile load. However, prohibiting current cutoff may result in the storage device being overcharged by the charging current supplied from the alternator thereafter, which may result in a loss of battery performance. Loss of battery performance means that the device can no longer be charged or discharged. If all the power storage devices lose their battery performance, power will no longer be supplied to the mobile load. If power is no longer supplied to the mobile load while the mobile body is traveling, power will no longer be supplied to the control unit of the power supply system, the brake system, the power steering, etc., and the mobile body may not be able to stop safely. If power is no longer supplied to the mobile load, the hazard lights will also not be able to be turned on. For this reason, it is desirable to secure enough time for the mobile body to stop safely even if all the power storage devices become abnormal.

[0024] According to the above control method, when all of the power storage devices are abnormal, current cutoff is prohibited for two or more power storage devices, so the charging current can be shared and received by two or more power storage devices. When the charging current is shared and received by two or more power storage devices, the voltage rise of each power storage device is slower than when only one power storage device receives the charging current, so the time until the power storage device becomes overcharged (in other words, the time until the battery performance is lost) is longer. This ensures the time during which the moving object can be stopped safely.

[0025] (7) In the first step, when all of the power storage devices are abnormal, it may be determined which of the power storage devices is to be prohibited from cutting off current based on the type of abnormality in each of the power storage devices.

[0026] If an abnormality occurs in a power storage device, the power storage device may become completely unusable if the current cutoff to the power storage device is continued. However, the possibility of the power storage device becoming completely unusable differs depending on the type of abnormality. According to the above control method, the decision as to which storage device to prohibit current interruption is based on the type of abnormality, thereby reducing the possibility of the storage device becoming completely unusable compared to when the decision is made regardless of the type of abnormality.

[0027] (8) In the first step, when two or more of the energy storage devices are normal, if it is assumed that one of the normal energy storage devices becomes abnormal and the current interruption device of that energy storage device is put into an interrupted state, and the total remaining power of the other normal energy storage devices is less than the amount of power required for the power supply system, current interruption may be prohibited for all of the normal energy storage devices.

[0028] Assume that the amount of power required for the power supply system is 100. Assume that there are normal power storage devices A and B, and that the remaining power of power storage device A is 70 and the remaining power of power storage device B is 60. In this case, the sum of the remaining power of power storage device A and the remaining power of power storage device B is 130, which is more than the amount of power required for the power supply system (=100). In this case, if it is assumed that power storage device A becomes abnormal, for example, the only normal power storage device will be power storage device B, and the sum of the remaining power of the other normal power storage devices will be 60, which is less than the amount of power required for the power supply system. According to the above control method, if it is assumed that any of the normal power storage devices becomes abnormal and the current interruption device of that power storage device is set to an interrupted state, and the total remaining power of the other normal power storage devices is less than the amount of power required for the power supply system, current interruption is prohibited for all normal power storage devices, so that the amount of power required for the power supply system can be secured even if any of the power storage devices becomes abnormal. This more reliably reduces the risk of power not being supplied to the mobile load.

[0029] (9) A power supply system for a mobile body comprising: a plurality of power storage devices connected to a mobile body load and connected in parallel to each other; and a control unit, wherein the power storage devices comprise a power storage element, a current interruption device connected in series to the power storage element, and a management device, and the control unit executes a first process of permitting or prohibiting current interruption for each of the power storage devices based on a combination of normality and abnormality of each of the power storage devices so that the current interruption device of at least one of the power storage devices is in a conducting state; and a second process of putting the current interruption device into an interrupted state when the management device of the power storage device permitted to interrupt the current detects an abnormality in the power storage device at the time when current interruption is permitted, or when an abnormality in the power storage device is detected after current interruption is permitted.

[0030] According to the power supply system described above, it is possible to reduce the risk that power will not be supplied to the mobile load even if all of the multiple power storage devices connected in parallel experience an abnormality.

[0031] (10) A power supply system of a mobile body, comprising a plurality of energy storage devices connected to a mobile body load and connected in parallel to each other, the energy storage devices comprising an energy storage element, a current interruption device connected in series to the energy storage element, and a management device, any one of the management devices executes a first process to permit or prohibit current interruption for each of the energy storage devices based on a combination of normal and abnormal states of each of the energy storage devices so that the current interruption device of at least one of the energy storage devices is in an energized state, and the management device of a storage device that is permitted to interrupt current executes a second process to place the current interruption device in an interrupted state if an abnormality in the storage device is detected at the time interruption of the current is permitted, or if an abnormality in the storage device is detected after interruption of the current is permitted.

[0032] According to the power supply system described above, it is possible to reduce the risk that power will not be supplied to the mobile load even if all of the multiple power storage devices connected in parallel experience an abnormality.

[0033] (11) A power storage device used in a power supply system of a mobile body, comprising: a power storage element; a current interruption device connected in series with the power storage element; and a management device, wherein the management device executes a third process of detecting whether the power storage device is normal or abnormal and transmitting the result to an external device; a fourth process of receiving from the external device an permission signal that permits current interruption or a prohibition signal that prohibits current interruption; and a second process of setting the current interruption device to an interrupted state if an abnormality in the power storage device has been detected at the time the permission signal is received, or if an abnormality in the power storage device is detected after the permission signal is received.

[0034] According to the above-described power storage device, it is possible to reduce the risk that power will not be supplied to the mobile load even if all of the multiple power storage devices connected in parallel become abnormal.

[0035] The invention disclosed in this specification can be realized in various forms, such as an apparatus, a method, a computer program for implementing the functions of these apparatus or methods, and a recording medium on which the computer program is recorded.

[0036] <Embodiment 1> The first embodiment will be described with reference to Figures 1 to 10. In the following description, the reference numerals of the drawings may be omitted for the same components, with some exceptions.

[0037] (1-1) Vehicle power supply system A vehicle 10 (an example of a moving body) shown in FIG. 1 is an engine-driven vehicle, and is equipped with an engine starting device 21 such as a starter motor and a power supply system 30. 2, the vehicle 10 is also equipped with an alternator 23, which is a vehicle generator, and an electrical load 25. The electrical load 25 has a rated voltage of 12 V, and examples of the electrical load include an air conditioner, an audio system, and a car navigation system. The engine starting device 21 and the electrical load 25 are examples of mobile loads.

[0038] The power supply system 30 includes a vehicle ECU (Electronic Control Unit) 31, a first power storage device 50A (an example of a power storage device), a second power storage device 50B (an example of a power storage device), and a DC-DC converter 35. In the following description, when there is no need to distinguish between the first power storage device 50A and the second power storage device 50B, they are simply referred to as power storage devices 50. The same applies to the other components.

[0039] The vehicle ECU 31 (a control unit, an example of an external device) is a control unit of the power supply system 30. The vehicle ECU 31 is connected to be able to communicate with the first power storage device 50A, the second power storage device 50B, and the DC-DC converter 35. The vehicle ECU 31 includes a CPU 32, a RAM 33, a ROM 34, and the like. The ROM 34 stores various control programs executed by the CPU 32. The vehicle ECU 31 is started, for example, when the ignition switch of the vehicle 10 is turned on or the start button is pressed. The vehicle ECU 31 may be constantly started by receiving power from the first power storage device 50A or the second power storage device 50B even while the ignition switch is turned off.

[0040] The vehicle ECU 31 controls the DC-DC converter 35 to control charging and discharging of the power storage device 50. The vehicle ECU 31 can obtain information on the operating state of the engine and the running state of the vehicle 10 from another ECU that controls the engine (drive device) of the vehicle 10. As will be described in detail later, the vehicle ECU 31 receives the states (normal, abnormal) of the power storage devices 50 at regular intervals, and also executes a process of permitting or prohibiting cut-off of current to each power storage device 50 based on a combination of normality and abnormality of each power storage device 50 so that at least one power storage device 50 is in a conducting state.

[0041] The first power storage device 50A is connected to a power line 37. The engine starting device 21, the alternator 23, and the electric load 25 are connected to the first power storage device 50A via the power line 37. The first power storage device 50A includes a first current interruption device 53A (an example of a current interruption device), a first assembled battery 60A, and a first BMU 100A (Battery Management Unit). The first power storage device 50A has a rated voltage of 12V. The first BMU 100A is an example of a management device.

[0042] The second power storage device 50B is connected in parallel to the first power storage device 50A via a DC-DC converter 35. The second power storage device 50B includes a second current interruption device 53B (an example of a current interruption device), a second assembled battery 60B, and a second BMU 100B. The second power storage device 50B has a rated voltage of 12 V. The second BMU 100B is an example of a management device.

[0043] DC-DC converter 35 is a bidirectional DC-DC converter capable of controlling charging and discharging of second power storage device 50B. DC-DC converter 35 is an adjustment device that controls charging and discharging of second power storage device 50B. The adjustment device may be something other than DC-DC converter 35. The DC-DC converter 35 can control the voltage at point A on the load side to control the power supply from the second power storage device 50B to the electric load 25. By making the voltage at point A higher than the output voltage of the alternator 23, power is supplied to the electric load 25, and by making the voltage at point A lower than the output voltage of the alternator 23, the power supply to the electric load 25 can be stopped (discharge control).

[0044] The DC-DC converter 35 can control the power supply to the second power storage device 50B by controlling the voltage at point B on the second power storage device 50B side. By making the voltage at point B higher than the output voltage of the second power storage device 50B, power is supplied to the second power storage device 50B from the alternator 23 via the power line 37, and by making the voltage at point B lower than the output voltage of the second power storage device 50B, the power supply to the second power storage device 50B can be stopped (charging control).

[0045] By connecting two power storage devices 50 in parallel, even if an abnormality occurs in one of the power storage devices 50 (e.g., first power storage device 50A: main power storage device), the other power storage device 50 (e.g., second power storage device 50B: sub power storage device) can continue to supply power to the vehicle 10, thereby providing redundancy to the power source for the vehicle 10.

[0046] (1-2) Configuration of the Energy Storage Device As shown in FIG. 3, the first power storage device 50A includes a first assembled battery 60A, a first current interrupt device 53A connected in series with the first assembled battery 60A, a first BMU 100A, and a connector 57.

[0047] The first BMU 100A includes a current sensor 54, which will be described in detail later. The first current interrupting device 53A, the first assembled battery 60A, and the current sensor 54 are connected in series via power lines 55P and 55N. The power line 55P is a power line that connects the positive external terminal 51 and the positive electrode of the first assembled battery 60A. The power line 55N is a power line that connects the negative external terminal 52 and the negative electrode of the first assembled battery 60A. The first current interrupting device 53A is located on the positive electrode side of the first assembled battery 60A and is provided on the positive electrode side power line 55P. The current sensor 54 is located on the negative electrode side of the first assembled battery 60A and is provided on the negative electrode power line 55N.

[0048] The first assembled battery 60A has 12 secondary batteries 62 (an example of power storage elements) connected in three parallel and four in series. In Fig. 3, the three parallel-connected secondary batteries 62 are represented by one battery symbol. The secondary batteries 62 are, for example, lithium-ion secondary batteries. The first current interrupting device 53A is configured by a contact switch (mechanical type) such as a relay, or a semiconductor switch such as a FET or a transistor. The first current interrupting device 53A is switched between a cut-off state and a conducting state (open / closed, open / closed, off / on) by the first BMU 100A. When the first current interrupting device 53A is in the cut-off state, the first power storage device 50A is disconnected from the power line 37 of the vehicle 10, and the current is interrupted. When the first current interrupting device 53A is in the conducting state, the first power storage device 50A is connected to the power line 37, and power can be supplied to the vehicle 10.

[0049] The first BMU 100A includes a current sensor 54, a voltage detection circuit 110, a temperature sensor 115, and a management section 120. The voltage detection circuit 110 and the management section 120 are mounted on a circuit board unit 65 (see FIG. 4). The current sensor 54 measures the charge / discharge current [A] of the first assembled battery 60A and outputs the result to the management unit 120.

[0050] The voltage detection circuit 110 is connected by signal lines to both ends of each secondary battery 62. The voltage detection circuit 110 measures the battery voltage [V] of each secondary battery 62 and outputs it to the management unit 120. The total voltage [V] of the first assembled battery 60A is the sum of the voltages of the four secondary batteries 62 connected in series. The temperature sensor 115 is of a contact type or a non-contact type, and measures the temperature [°C] of the secondary battery 62 and outputs the measured temperature to the management unit 120. Although omitted in Fig. 3, two or more temperature sensors 115 are provided. Each temperature sensor 115 detects a different temperature of the secondary battery 62.

[0051] The management unit 120 includes a microcomputer 121 in which a CPU, a RAM, and the like are integrated into one chip, a ROM 123, and a communication unit 125. Various programs and data are stored in the ROM 123. The microcomputer 121 manages the first power storage device 50A by executing the programs stored in the ROM 123. The first connector 57 is a connector to which a communication cable is connected, for connecting the first power storage device 50A to the vehicle ECU 31 so as to enable communication therebetween.

[0052] As shown in Fig. 4, first power storage device 50A includes a container 71. Container 71 includes a main body 73 and a cover 74 made of a synthetic resin material. Main body 73 is cylindrical with a bottom. Main body 73 includes a bottom portion 75 and four side portions 76. An upper opening 77 is formed at the upper end portion by the four side portions 76. The container 71 houses the first assembled battery 60A and the circuit board unit 65. The circuit board unit 65 is disposed above the first assembled battery 60A.

[0053] The lid 74 closes an upper opening 77 of the main body 73. An outer peripheral wall 78 is provided around the lid 74. The lid 74 has a protruding portion 79 that is generally T-shaped in plan view. The positive external terminal 51 is fixed to one corner of the front of the lid 74, and the negative external terminal 52 is fixed to the other corner. 5A and 5B, secondary battery 62 contains an electrode assembly 83 together with a non-aqueous electrolyte in a rectangular parallelepiped case 82. Case 82 has a case body 84 and a lid 85 that closes the upper opening thereof.

[0054] Although the details of the electrode body 83 are not shown, a separator made of a porous resin film is disposed between a negative electrode element made of a copper foil substrate coated with an active material and a positive electrode element made of an aluminum foil substrate coated with an active material. Both of these are strip-shaped, and are wound flatly so that they can be housed in the case body 84, with the negative electrode element and the positive electrode element shifted to opposite sides in the width direction relative to the separator.

[0055] A positive electrode terminal 87 is connected to the positive electrode element via a positive electrode collector 86, and a negative electrode terminal 89 is connected to the negative electrode element via a negative electrode collector 88. The positive electrode collector 86 and the negative electrode collector 88 each include a flat base 90 and a leg 91 extending from the base 90. A through hole is formed in the base 90. The leg 91 is connected to the positive electrode element or the negative electrode element. The positive electrode terminal 87 and the negative electrode terminal 89 each include a terminal body 92 and a shaft 93 protruding downward from the center of the lower surface of the terminal body 92. Of these, the terminal body 92 and the shaft 93 of the positive electrode terminal 87 are integrally formed from aluminum (a single material). In the negative electrode terminal 89, the terminal body 92 is made of aluminum, and the shaft 93 is made of copper, and these are assembled together. The terminal main bodies 92 of the positive electrode terminal 87 and the negative electrode terminal 89 are disposed on both ends of the lid 85 via gaskets 94 made of an insulating material, and are exposed to the outside from the gaskets 94 . The lid 85 has a pressure relief valve 95. As shown in Fig. 5A, the pressure relief valve 95 is located between the positive terminal 87 and the negative terminal 89. The pressure relief valve 95 opens to reduce the internal pressure of the case 82 when the internal pressure of the case 82 exceeds a limit value.

[0056] 6, the second power storage device 50B includes a second assembled battery 60B including a plurality of secondary batteries 62, a second current interrupting device 53B connected in series to the second assembled battery 60B, a second BMU 100B, and a connector 57. The structure of the second power storage device 50B is substantially the same as that of the first power storage device 50A, and therefore detailed description thereof will be omitted.

[0057] (1-3) Charging curve FIG. 7 shows a charging curve when the secondary battery 62 is charged at a predetermined rate, with the horizontal axis representing time and the vertical axis representing voltage. Va is the threshold voltage at which the current interrupter 53 is switched to an interrupted state (the upper limit voltage at which the secondary battery 62 can be used safely), and is 4V as an example. Vb is the limit voltage at which the secondary battery 62 loses its battery performance, and is 5.8V as an example. Losing battery performance means that neither charging nor discharging can be performed. Vc is the voltage at which the pressure release valve 95 operates, and is 7V as an example.

[0058] (1-4) Power supply system control method The BMU 100 (first BMU 100A, second BMU 100B) of each power storage device 50 (first storage device 50A, second storage device 50B) detects the state (normal, abnormal) of the power storage device 50 at a predetermined cycle (for example, 10 milliseconds) and transmits a state signal indicating the detected state to the vehicle ECU 31. When the vehicle ECU 31 receives the state signal from each BMU 100, it permits or prohibits each power storage device 50 from cutting off current based on a combination of normality and abnormality of each power storage device 50 so that at least one power storage device 50 is in a conducting state. If the BMU 100 of the power storage device 50 permitted to cut off the current detects an abnormality in the power storage device 50 at the time when the BMU 100 is permitted to cut off the current, it sets the current cut-off device 53 to the cut-off state to cut off the current. This will be specifically described below.

[0059] (1-4-1) Detection of the state of the storage device Detecting the state of the power storage device 50 means detecting whether the power storage device 50 is normal or abnormal. Abnormalities in the power storage device 50 include abnormalities in the secondary battery 62 and abnormalities in the BMU 100. Detection of abnormalities in the secondary battery 62 and detection of abnormalities in the BMU 100 will be described below.

[0060] (1-4-1-1) Detection of secondary battery abnormalities Specifically, abnormalities in the secondary battery 62 include overcharging, overdischarging, overcurrent, and temperature abnormality. The BMU 100 measures the current value at regular intervals using the current sensor 54, and estimates the state of charge (SOC) using the current integration method. The current integration method is a method in which the charge / discharge current of the battery pack is constantly measured using the current sensor 54 to measure the amount of power flowing in and out of the battery pack, and the SOC is estimated by adding or subtracting this from the initial capacity. If the estimated SOC is greater than a predetermined upper limit, the BMU 100 determines that the battery is overcharged, and if it is less than a predetermined lower limit, it determines that the battery is overdischarged. An example of a cause of the secondary battery 62 being overcharged is a malfunction of the alternator 23.

[0061] Here, an example has been described in which overcharging or overdischarging is determined from the SOC estimated by the current integration method, but the determination may also be made from a voltage value measured by the voltage detection circuit 110. Specifically, since there is a relatively accurate correlation between the open circuit voltage (OCV) of the power storage device 50 and the SOC, it may be determined that the battery is overcharged when the voltage measured by the voltage detection circuit 110 is equal to or higher than a predetermined upper limit voltage, and may be determined to be overdischarged when the voltage measured by the voltage detection circuit 110 is equal to or lower than a predetermined lower limit voltage.

[0062] Each time the BMU 100 measures the current value with the current sensor 54, it determines whether the measured current value is equal to or greater than a predetermined value, and if it is equal to or greater than the predetermined value, it determines that an overcurrent has occurred. Examples of causes of an overcurrent include a failure of the alternator 23 and an external short circuit. The BMU 100 measures the temperature of the secondary battery 62 at regular intervals using the temperature sensor 115, and if the measured temperature is equal to or higher than a predetermined value, it determines that a temperature abnormality has occurred. Although the abnormalities of the secondary battery 62 have been described above as being overcharged, overdischarged, overcurrent, and abnormal temperature, the abnormalities of the secondary battery 62 are not limited to these.

[0063] (1-4-1-2) Detection of BMU abnormalities An abnormality in the BMU 100 is specifically an abnormality in the components (management unit 120, current sensor 54, voltage detection circuit 110, temperature sensor 115, communication unit 125, etc.) that make up the BMU 100. For convenience, in this embodiment, the current interruption device 53 is not included in the components of the BMU 100, so an abnormality in the current interruption device 53 is not included in the abnormality of the BMU 100.

[0064] The BMU 100 performs self-diagnosis at a predetermined cycle to detect abnormalities in the BMU 100. Specifically, for example, to detect an abnormality in the management unit 120, the BMU 100 performs a CRC (Cyclic Redundancy Check) of the ROM 34, and if the value differs from a value stored in advance, it is determined that the management unit 120 is abnormal. An abnormality in the current sensor 54 can be detected by various methods. For example, two current sensors 54 may be provided, and the BMU 100 may determine that there is an abnormality in the current sensor 54 when the difference in the detection results between the two is equal to or greater than a predetermined value. Alternatively, an abnormality may be detected by providing a circuit for detecting an abnormality in the current sensor 54. The same applies to the voltage detection circuit 110. In detecting an abnormality in the temperature sensor 115, the BMU 100 detects the temperature of the secondary battery 62 using multiple temperature sensors 115, and if the difference between the detection results is equal to or greater than a predetermined value, determines that the temperature sensor 115 is abnormal. In detecting an abnormality in the communication unit 125, the BMU 100 counts the number of times a communication error has occurred, and determines that the communication unit 125 is abnormal if the number of occurrences is equal to or greater than a predetermined value. The method of detecting an abnormality in the BMU 100 is not limited to the above-mentioned method, and the abnormality can be detected by any appropriate method.

[0065] (1-4-2) Permitting or prohibiting the vehicle ECU from cutting off the current Permission or prohibition of current interruption according to the first embodiment will be described with reference to Table 1 shown below. [Table 1]

[0066] When all of the power storage devices 50 are normal, the vehicle ECU 31 prohibits the interruption of current to all of the power storage devices. When there are normal power storage devices 50 and abnormal power storage devices 50 (when the number of normal power storage devices 50 is one or more and the number of abnormal power storage devices 50 is one or more), the vehicle ECU 31 permits current interruption to the abnormal power storage device 50. For example, when the number of power storage devices 50 is two and both of the two power storage devices 50 are normal, current interruption is prohibited to the two power storage devices 50. If one of the two power storage devices 50 subsequently becomes abnormal, a state will be created in which there is a normal power storage device 50 and an abnormal power storage device 50, and therefore current interruption is permitted to the abnormal power storage device 50. This makes it possible to protect the power storage devices 50 from abnormalities. Since current interruption is prohibited for the normal power storage device 50, it is possible to reduce the risk of power not being supplied to the mobile load.

[0067] When all the power storage devices 50 are abnormal, the vehicle ECU 31 prohibits current interruption for two or more power storage devices 50. In the first embodiment, since the number of power storage devices 50 is two, as a result, current interruption is prohibited for all the power storage devices 50. For example, when the number of power storage devices 50 is two and one of the two power storage devices 50 becomes abnormal, current interruption is permitted for one of the power storage devices 50. If the other power storage device 50 subsequently also becomes abnormal, current interruption is prohibited for the one of the power storage devices 50. In this way, current interruption is prohibited for two or more power storage devices 50.

[0068] In the event that all of the power storage devices 50 become abnormal, if current cutoff is prohibited for two or more power storage devices 50, the charging current is shared and received by the two or more power storage devices 50. When the charging current is shared and received by the two or more power storage devices 50, the voltage rise of each power storage device 50 is slower than when only one power storage device 50 receives the charging current, so the time until the battery performance of the power storage devices 50 is lost becomes longer. Therefore, even if all of the power storage devices 50 become abnormal while the vehicle 10 is traveling, the time for the vehicle 10 to be safely stopped can be secured.

[0069] (1-4-3) Sequence A sequence of a control method for power supply system 30 will be described with reference to Fig. 8 to Fig. 10. When power supply system 30 is started, power is supplied to engine starting device 21 to drive the engine of vehicle 10. When the engine starts to drive, alternator 23 starts generating power. When the amount of power generated by alternator 23 exceeds electric load 25, a charging current flows to two power storage devices 50, and two power storage devices 50 are charged.

[0070] The sequence shown in Fig. 8 is started upon start-up of power supply system 30. At the start of the sequence shown in Fig. 8, each power storage device 50 is normal, and current interruption device 53 of each power storage device 50 is in an energized state. The first BMU 100A detects the state (normal, abnormal) of the first power storage device 50A (S101), and transmits a state signal (normal) indicating the detected state to the vehicle ECU 31 (S102, an example of a third process). The second BMU 100B detects the state of the second power storage device 50B (S103), and transmits a state signal (normal) indicating the detected state to the vehicle ECU 31 (S104, an example of a third process).

[0071] When the vehicle ECU 31 receives the status signal from each BMU 100, it determines whether or not to permit current cutoff for each power storage device 50 based on Table 1 described above (S105). In the example shown in Fig. 8, all the power storage devices 50 are normal, so the vehicle ECU 31 determines to prohibit current cutoff for all the power storage devices 50. If all the power storage devices 50 are normal, the vehicle ECU 31 transmits a cutoff prohibition signal to all the power storage devices 50 (S105, S106). When the BMU 100 receives the cutoff prohibition signal, it places the current cutoff device 53 in a conductive state regardless of whether the power storage device 50 is normal or abnormal (if the current cutoff device 53 is already in a conductive state, it maintains the conductive state).

[0072] Fig. 9 shows a sequence in the case where an abnormality occurs in the first power storage device 50A after the sequence shown in Fig. 8. At the start of the sequence shown in Fig. 9, each power storage device 50 is normal, and the current interruption device 53 of each power storage device 50 is in an energized state.

[0073] The first BMU 100A detects that the first power storage device 50A is abnormal (S201), and transmits a status signal indicating the abnormality to the vehicle ECU 31 (S202). Since the first BMU 100A is prohibited from cutting off the current in S105, the first BMU 100A maintains the energized state even when the abnormality is detected in S201. The second BMU 100B detects that the second power storage device 50B is normal (S203), and transmits a status signal indicating normality to the vehicle ECU 31 (S204).

[0074] When the vehicle ECU 31 receives the status signal from each BMU 100, it determines whether or not to permit current cut-off for each power storage device 50 based on Table 1 described above (S205). In the example shown in Fig. 9, there are normal power storage devices 50 and abnormal power storage devices 50, so the vehicle ECU 31 determines to permit current cut-off for the abnormal power storage device 50. Specifically, in the example shown in Fig. 9, the first power storage device 50A is abnormal and the second power storage device 50B is normal, so the vehicle ECU 31 determines to permit current cut-off for the first power storage device 50A.

[0075] When the first BMU 100A detects an abnormality in the first power storage device 50A in S201, it transmits a status signal (abnormality) to the vehicle ECU 31 in S202, and then transmits a cut-off permission request to the vehicle ECU 31 (S206, an example of a step of requesting permission to cut off current). When the vehicle ECU 31 receives the cutoff permission request from the first BMU 100A, since it has been determined in S205 that cutoff of the current is permitted for the first power storage device 50A, the vehicle ECU 31 transmits a cutoff permission signal to the first BMU 100A (S207, an example of a step of permitting or prohibiting cutoff of the current). When the first BMU 100A receives the cutoff permission signal, the first BMU 100A sets the first current cutoff device 53A to the cutoff state (S208).

[0076] Fig. 10 shows a sequence in the case where an abnormality occurs in second power storage device 50B after the sequence shown in Fig. 9. At the start of the sequence shown in Fig. 10, first power storage device 50A is abnormal and second power storage device 50B is normal. At the start of the sequence shown in Fig. 10, first current interruption device 53A is in an interrupted state and second current interruption device 53B is in an energized state.

[0077] The first BMU 100A detects that the first power storage device 50A is abnormal (S301), and transmits a status signal indicating the abnormality to the vehicle ECU 31 (S302). Since the first BMU 100A has received the cutoff permission signal in S207 shown in Fig. 9, the first BMU 100A maintains the current cutoff device 53 in the cutoff state. The second BMU 100B detects that the second power storage device 50B is abnormal (S303), and transmits a status signal indicating the abnormality to the vehicle ECU 31 (S304). Since the second BMU 100B received the cutoff prohibition signal in S106, the second BMU 100B maintains the current cutoff device 53 in the energized state even if it detects an abnormality.

[0078] When the vehicle ECU 31 receives a status signal from each BMU 100, it judges whether or not to permit current cutoff for each power storage device 50 based on Table 1 described above (S305). In the example shown in FIG. 10, all the power storage devices 50 are abnormal, so the vehicle ECU 31 judges to prohibit current cutoff for two or more power storage devices 50. In this embodiment, the number of power storage devices 50 is two, so it ultimately judges to prohibit current cutoff for all the power storage devices 50. Even if the vehicle ECU 31 judges to prohibit current cutoff for two or more power storage devices 50 (here, all the power storage devices 50), it does not immediately transmit a cutoff prohibition signal, but transmits the cutoff prohibition signal after receiving a cutoff permission request from each power storage device 50. A specific description will be given below.

[0079] When the first BMU 100A detects an abnormality in the first power storage device 50A in S301, it transmits a status signal (abnormality) to the vehicle ECU 31 in S302, and then transmits a cutoff permission request to the vehicle ECU 31 (S306). The first BMU 100A has already received the cutoff permission signal in S207, but in the first embodiment, it transmits a cutoff permission request every time an abnormality is detected. When the vehicle ECU 31 receives the cutoff permission request from the first BMU 100A, the vehicle ECU 31 transmits a cutoff prohibition signal to the first BMU 100A (S307) since it has determined that cutoff of current is prohibited for all the power storage devices 50. When the first BMU 100A receives the cutoff prohibition signal, the first BMU 100A switches the first current cutoff device 53A from a cutoff state to a conducting state (S308).

[0080] When the second BMU 100B detects an abnormality in the second power storage device 50B in S303, it transmits a state signal (abnormality) to the vehicle ECU 31 in S304, and then transmits a cutoff permission request to the vehicle ECU 31 (S309). When the vehicle ECU 31 receives the cutoff permission request from the second BMU 100B, the vehicle ECU 31 transmits a cutoff prohibition signal to the second BMU 100B because it has determined that current cutoff is prohibited for all the BMUs 100B (S310). Therefore, even if the second BMU 100B detects an abnormality in the second power storage device 50B, the second BMU 100B maintains the second current cutoff device 53B in a conducting state.

[0081] When it is determined that all of the power storage devices 50 are abnormal, the vehicle ECU 31 executes a warning process (S311). The warning process is a process for warning the driver to make an emergency stop of the vehicle 10. For example, the vehicle ECU 31 turns on an abnormality warning light (not shown) mounted on the vehicle 10. The lighting of the abnormality warning light can notify the driver of an abnormality in the vehicle 10 and urge the driver to make an emergency stop. A warning sound may also be emitted. If overcharging occurs due to a failure of the alternator 23, for example, the behavior of the vehicle 10 may be abnormal. In that case, it is difficult for the driver to notice the abnormality warning light, but urging the driver to make an emergency stop by voice also makes it easier for the driver to recognize the abnormality.

[0082] When the vehicle 10 makes an emergency stop and then the engine of the vehicle 10 stops, the ECU that controls the engine notifies the vehicle ECU 31 that the vehicle 10 has made an emergency stop and the engine has stopped. Upon receiving the notification, the vehicle ECU 31 transmits a cutoff permission signal to each BMU 100 (S312, S314). When each BMU 100 receives the cutoff permission signal from the vehicle ECU 31, it sets the current cutoff device 53 to the cutoff state (S313, S315). In this manner, after an emergency stop of the vehicle 10, the use of the first power storage device 50A and the second power storage device 50B can be prohibited.

[0083] (2-2) When communication between the vehicle ECU and the BMU is lost Assume that communication between the vehicle ECU 31 and the BMU 100 is interrupted at time T1 shown in Fig. 9. The first BMU 100A transmits a status signal (abnormal) to the vehicle ECU 31 in S202, and then transmits a cutoff permission request to the vehicle ECU 31 in S206. However, since communication with the vehicle ECU 31 has been interrupted at the time of S206, the first BMU 100A does not receive a response from the vehicle ECU 31. For this reason, the first BMU 100A remains prohibited from cutting off the current. The second power storage device 50B receives the cutoff prohibition signal in S106, and is therefore prohibited from cutting off the current.

[0084] 10 is executed thereafter, the first BMU 100A maintains the current interruption device 53 in a conducting state even if it detects an abnormality in S301, because current interruption is prohibited in S105. When the first BMU 100A detects an abnormality in the first power storage device 50A in S301, the first BMU 100A transmits a status signal (abnormality) to the vehicle ECU 31 in S302, and then transmits a request for interruption permission to the vehicle ECU 31 in S306. However, because communication with the vehicle ECU 31 has been cut off, no response is received from the vehicle ECU 31. For this reason, the first BMU 100A remains prohibited from interrupting the current.

[0085] Since the second BMU 100B is also prohibited from cutting off the current, even if an abnormality is detected in S303, the current cut-off device 53 is maintained in the energized state. When the second BMU 100B detects an abnormality in the second power storage device 50B in S303, it also transmits a status signal (abnormality) to the vehicle ECU 31 in S304, and then transmits a cut-off permission request to the vehicle ECU 31 in S309. However, since communication with the vehicle ECU 31 has been cut off, no response is received from the vehicle ECU 31. For this reason, the second BMU 100B remains prohibited from cutting off the current.

[0086] (1-5) Effects of the embodiment In the control method according to the first embodiment, current interruption is permitted or prohibited for each power storage device 50 based on a combination of normal and abnormal states of each power storage device 50 so that at least one power storage device 50 is in a conducting state, and if the BMU 100 of the power storage device 50 permitted to interrupt the current detects an abnormality in the power storage device 50 at the time when current interruption is permitted, the current interruption device 53 is set to an interruption state. Since the current interruption device 53 of the power storage device 50 permitted to interrupt the current is set to an interruption state, the power storage device 50 permitted to interrupt the current can be protected from an abnormality. Even if all the power storage devices 50 become abnormal, at least one power storage device 50 is connected to the vehicle 10, and therefore the risk of power not being supplied to the mobile load can be reduced compared to the case where none of the power storage devices 50 is connected to the vehicle 10.

[0087] According to the control method of the first embodiment, an abnormality in the power storage device 50 includes an abnormality in the BMU 100, so that it is possible to ensure the safety of the power storage device 50 in the event of an abnormality in the BMU 100 while reducing the risk of power being cut off from the mobile load.

[0088] According to the control method of the first embodiment, when all the power storage devices 50 are normal, current interruption is prohibited for each power storage device 50. In this way, if communication between the vehicle ECU 31 and the power storage devices 50 is subsequently interrupted, even if an abnormality occurs in the power storage device 50, the vehicle ECU 31 does not permit current interruption, and the power storage device 50 remains prohibited from interrupting current. This reduces the risk that power will not be supplied to the mobile load even if communication between the vehicle ECU 31 and the power storage devices 50 is interrupted. The control method of the first embodiment is particularly useful in the case of a power supply system in which it is strongly desired to reduce the risk that power will not be supplied to the mobile load.

[0089] According to the control method of the first embodiment, when all of the power storage devices 50 are abnormal, current cutoff is prohibited for two or more of the power storage devices 50, so the time until the power storage devices 50 are overcharged (in other words, the time until the battery performance is lost) is extended. This ensures the time during which the vehicle 10 can be stopped safely.

[0090] According to the power supply system 30 of the first embodiment, it is possible to reduce the risk that power will not be supplied to the mobile load even if all of the multiple power storage devices 50 connected in parallel become abnormal.

[0091] According to the power storage device 50 of the first embodiment, it is possible to reduce the risk that power will not be supplied to the mobile load even if all of the multiple power storage devices 50 connected in parallel become abnormal.

[0092] <Embodiment 2> In the second embodiment, when the number of normal power storage devices 50 is two or more, current interruption is permitted for all power storage devices 50. If the BMU 100 of a power storage device 50 permitted to interrupt the current detects an abnormality in the power storage device 50 after being permitted to interrupt the current, the BMU 100 switches the current interruption device 53 to an interrupted state and interrupts the current.

[0093] (1-4-2) Permitting or prohibiting the vehicle ECU from cutting off the current Permission or prohibition of current interruption according to the second embodiment will be described with reference to Table 2 shown below. [Table 2]

[0094] When the number of normal power storage devices 50 is two or more, the vehicle ECU 31 permits current interruption to all of the power storage devices 50. Since current interruption is permitted to all of the power storage devices 50, if the BMU 100 of each power storage device 50 subsequently detects an abnormality in the power storage device 50, the current interruption device 53 is set to the interrupted state. This makes it possible to protect the power storage device 50 from abnormalities.

[0095] When the number of normal power storage devices 50 is one, the vehicle ECU 31 permits current interruption to the abnormal power storage device 50, while prohibiting current interruption to the one power storage device 50 remaining as the normal power storage device 50 until the end. For example, when the number of normal power storage devices 50 is two, those power storage devices 50 are permitted to interrupt current. If one of the two power storage devices 50 subsequently becomes abnormal, the number of normal power storage devices 50 becomes one, and therefore current interruption is prohibited to the one power storage device 50 remaining as the normal power storage device 50 until the end. By prohibiting current interruption to the one power storage device 50 remaining as the normal power storage device 50 until the end, the risk of power not being supplied to the mobile load can be reduced. Table 2 is substantially the same as Table 1 in other respects, so a detailed explanation will be omitted.

[0096] (2-1) Sequence The sequence of the control process of the power supply system 30 according to the second embodiment will be described with reference to FIGS.

[0097] The sequence shown in Fig. 11 is started upon start-up of power supply system 30. At the start of the sequence shown in Fig. 11, each power storage device 50 is normal, and current interruption device 53 of each power storage device 50 is in an energized state. The first BMU 100A detects the state (normal, abnormal) of the first power storage device 50A (S401), and transmits a state signal indicating the detected state to the vehicle ECU 31 (S402, an example of a third process). The second BMU 100B detects the state of the second power storage device 50B (S403), and transmits a state signal indicating the detected state to the vehicle ECU 31 (S404, an example of a third process).

[0098] When the vehicle ECU 31 receives the state signal from each BMU 100, it judges whether or not to permit current cutoff for each power storage device 50 based on the above-mentioned Table 2 (S405). The vehicle ECU 31 transmits a cutoff permission signal (an example of a permission signal) to the BMU 100 of the power storage device 50 for which it has determined that cutoff of the current is permitted, and transmits a cutoff prohibition signal (an example of a prohibition signal) to the BMU 100 of the power storage device 50 for which it has determined that cutoff of the current is prohibited. 11, since two or more power storage devices 50 are normal, the vehicle ECU 31 determines to permit cut-off of current to all of the power storage devices 50. Therefore, the vehicle ECU 31 transmits a cut-off permission signal to all of the BMUs 100 (S406, S407, an example of the first step, the first process, and the fourth process).

[0099] In the example shown in Fig. 11, when the first BMU 100A receives the cutoff permission signal, the first storage device 50A is normal and the first current cutoff device 53A is already in a conducting state. Therefore, the first BMU 100A maintains the first current cutoff device 53A in a conducting state. The same applies to the second storage device 50B.

[0100] Fig. 12 shows a sequence in the case where an abnormality occurs in the first power storage device 50A after the sequence shown in Fig. 11. At the start of the sequence shown in Fig. 12, all of the power storage devices 50 are normal, and the current interruption devices 53 of each power storage device 50 are in an energized state.

[0101] The first BMU 100A detects that the first power storage device 50A is abnormal (S501), and transmits a status signal indicating the abnormality to the vehicle ECU 31 (S502). Since the first BMU 100A has already received the cutoff permission signal in S406 shown in Fig. 11, when the first BMU 100A detects an abnormality in S501, it sets the first current cutoff device 53A to the cutoff state to cut off the current (S503, an example of the second step and the second process). The second BMU 100B detects that the second power storage device 50B is normal (S504), and transmits a status signal indicating normality to the vehicle ECU 31 (S505).

[0102] When the vehicle ECU 31 receives the status signal from each BMU 100, it judges whether or not to permit current cutoff for each power storage device 50 based on Table 2 described above (S506). In the example shown in Fig. 12, since the number of normal power storage devices 50 is one, the vehicle ECU 31 judges to permit current cutoff for the abnormal power storage device 50 (first power storage device 50A) and to prohibit current cutoff for the normal power storage device 50 (second power storage device 50B). Therefore, the vehicle ECU 31 transmits a cutoff permission signal to the first BMU 100A (S507) and transmits a cutoff prohibition signal to the second BMU 100B (S5208).

[0103] 12, the first BMU 100A maintains the first current interrupting device 53A in the interrupted state because the first power storage device 50A is abnormal and the first current interrupting device 53A is already in the interrupted state when the first BMU 100A receives the interruption permission signal in S507. The second BMU 100B maintains the second current interrupting device 53B in the conductive state because the second current interrupting device 53B is already in the conductive state when the second BMU 100B receives the interruption prohibition signal in S508.

[0104] Fig. 13 shows a sequence in the case where an abnormality occurs in second power storage device 50B after the sequence shown in Fig. 12. At the start of the sequence shown in Fig. 13, first power storage device 50A is abnormal and second power storage device 50B is normal. At the start of the sequence shown in Fig. 13, first current interruption device 53A is in an interrupted state and second current interruption device 53B is in an energized state.

[0105] The first BMU 100A detects that the first power storage device 50A is abnormal (S601), and transmits a status signal indicating the abnormality to the vehicle ECU 31 (S602). Since the first BMU 100A receives the cutoff permission signal in S507 shown in Fig. 12, the first BMU 100A maintains the first current cutoff device 53A in the cutoff state. The second BMU 100B detects that the second power storage device 50B is abnormal (S603), and transmits a status signal indicating the abnormality to the vehicle ECU 31 (S604). Since the second BMU 100B has received the cutoff prohibition signal in S508 shown in Fig. 12, the second BMU 100B maintains the second current cutoff device 53B in a conducting state even if it detects an abnormality.

[0106] When the vehicle ECU 31 receives the status signal from each BMU 100, it judges whether or not to permit current cutoff for each power storage device 50 based on Table 2 described above (S605). In the example shown in FIG. 13, all the power storage devices 50 are abnormal, so the vehicle ECU 31 judges to prohibit current cutoff for two or more power storage devices 50. In this embodiment, the number of power storage devices 50 is two, so it is determined that current cutoff is prohibited for all the power storage devices 50. Therefore, the vehicle ECU 31 transmits a cutoff prohibition signal to the first BMU 100A and the second BMU 100B (S606, S608).

[0107] Since the first current interruption device 53A is in an interrupted state when the first BMU 100A receives the interruption prohibition signal, the first BMU 100A immediately switches the first current interruption device 53A to an energized state (S607). Since the second current interruption device 53B is already in an energized state when the second BMU 100B receives the interruption prohibition signal, the second BMU 100B maintains the second current interruption device 53B in an energized state.

[0108] (2-3) Effects of the embodiment According to the control method of the second embodiment, when the number of normal power storage devices 50 is two or more, current cut-off is permitted for all power storage devices 50, so that in the case of an abnormal power storage device 50, the current is immediately cut off, and in the case of a normal power storage device 50, the current is cut off when the normal power storage device 50 subsequently becomes abnormal. This ensures the safety of the power storage devices 50. When two power storage devices 50 are normal, if one of the power storage devices 50 subsequently becomes abnormal, there will be only one normal power storage device 50. When there is only one normal power storage device 50, the current cut-off for that power storage device 50 is prohibited, thereby reducing the risk of power not being supplied to the mobile load.

[0109] <Embodiment 3> In the above-described first embodiment, the vehicle ECU 31 permits or prohibits current interruption for each BMU 100. In contrast, in the third embodiment, instead of the vehicle ECU 31, the first BMU 100A permits or prohibits current interruption for each BMU 100 (including the first BMU 100A).

[0110] (3-1) Power supply system configuration As shown in FIG. 14, in a power supply system 30 according to the third embodiment, a first power storage device 50A and a second power storage device 50B are connected by a signal line 210 so as to be able to communicate with each other.

[0111] The second BMU 100B transmits a state signal indicating the state of the second storage device 50B to the first BMU 100A. The first BMU 100A judges whether or not to permit current interruption for each storage device 50 (including the first storage device 50A) based on the state of the first storage device 50A and the state of the second storage device 50B. This judgment is made based on Table 1 described above. When permitting current interruption for the first storage device 50A, the first BMU 100A permits current interruption for itself, and when prohibiting current interruption, prohibits current interruption for itself. When permitting current interruption for the second storage device 50B, the first BMU 100A transmits a cutoff permission signal, and when prohibiting current interruption, transmits a cutoff prohibition signal.

[0112] Here, an example has been described in which the first BMU 100A permits or prohibits each BMU 100 from cutting off current, but the second BMU 100B may be configured to permit or prohibit each BMU 100 (including the second BMU 100B) from cutting off current.

[0113] (3-2) Effects of the embodiment According to the power supply system 30 of the third embodiment, it is possible to reduce the risk that power will not be supplied to the mobile load even if all of the multiple power storage devices 50 connected in parallel become abnormal.

[0114] <Embodiment 4> A fourth embodiment will be described with reference to Fig. 15. The fourth embodiment is a modification of the first to third embodiments. Here, a modification of the second embodiment will be described as an example. In the control method of embodiment 4, when two or more storage devices 50 are normal, if it is assumed that one of the normal storage devices 50 becomes abnormal and the current interruption device 53 of that storage device 50 is switched to an interrupted state, and the total remaining power of the other normal storage devices 50 is less than the amount of power required for the power supply system 30, the BMUs 100 of all normal storage devices 50 are prohibited from interrupting current in order to ensure the amount of power required for the power supply system 30.

[0115] In the fourth embodiment, three power storage devices 50 (the first power storage device 50A described above, the second power storage device 50B described above, and a third power storage device 50C (not shown)) are connected in parallel. The total remaining power of the second power storage device 50B and the third power storage device 50C is greater than the amount of power required for the power supply system 30. However, the remaining power of each of the second power storage device 50B and the third power storage device 50C is less than the amount of power required for the power supply system 30.

[0116] (4-1) Sequence A sequence according to the fourth embodiment will be described with reference to Fig. 15. In Fig. 15, a third BMU 100C is a BMU for a third power storage device 50C. Fig. 15 shows a sequence corresponding to Fig. 9 in the first embodiment. At the start of the sequence shown in Fig. 15, each power storage device 50 is normal, and the current interruption device 53 of each power storage device 50 is in an energized state. At the start of the sequence shown in Fig. 15, the BMU 100 of each power storage device 50 has already received an interruption permission signal from the vehicle ECU 31.

[0117] The first BMU 100A detects that the first power storage device 50A is abnormal (S701), and transmits a status signal indicating the abnormality to the vehicle ECU 31 (S702). Since the first BMU 100A has already received the cutoff permission signal, when the first BMU 100A detects the abnormality in S701, it sets the first current cutoff device 53A to the cutoff state to cut off the current (S703, an example of the second step and the second process).

[0118] The second BMU 100B detects that the second power storage device 50B is normal (S704), and transmits a status signal indicating normality to the vehicle ECU 31 (S705). The third BMU 100C detects that the third power storage device 50C is normal (S706), and transmits a status signal indicating normality to the vehicle ECU 31 (S707).

[0119] When the vehicle ECU 31 according to the fourth embodiment receives the state information from each BMU 100, since two or more power storage devices 50 are normal, the vehicle ECU 31 permits current interruption to the first power storage device 50A in which an abnormality has occurred (S709).

[0120] When two or more power storage devices 50 are normal, the vehicle ECU 31 assumes that one of the normal power storage devices 50 (the second power storage device 50B and the third power storage device 50C) has become abnormal and has set the current interruption device 53 of the abnormal power storage device 50 to an interrupted state, and determines whether or not the total remaining power of the other normal power storage devices 50 is less than the amount of power required for the power supply system 30 (S708). The total remaining power of the second power storage device 50B and the third power storage device 50C is equal to or greater than the amount of power required for the power supply system 30, but the remaining power of each of the second power storage device 50B and the third power storage device 50C is less than the amount of power required for the power supply system 30. For this reason, when the current of one of the second power storage device 50B and the third power storage device 50C is interrupted, the total remaining power of the other normal power storage devices 50 becomes less than the amount of power required for the power supply system 30. Therefore, the vehicle ECU 31 prohibits cut-off of current to all normal power storage devices 50 (the second power storage device 50B and the third power storage device 50C). Specifically, the vehicle ECU 31 transmits a cut-off prohibition signal to the second BMU 100B and the third BMU 100C (S710, S711).

[0121] (4-2) Effects of the embodiment According to the control method of the fourth embodiment, even if the power storage device 50 becomes abnormal, the amount of power required by the power supply system 30 can be secured, thereby reducing the risk of power not being supplied to the mobile load.

[0122] <Embodiment 5> The fifth embodiment is a modification of the first to fourth embodiments. Here, it will be described as a modification of the second embodiment. In the second embodiment described above, the abnormality of the power storage device 50 includes an abnormality of the secondary battery 62 and an abnormality of the BMU 100. In contrast, in the fifth embodiment, the abnormality of the power storage device 50 refers to an abnormality of the BMU 100. Therefore, in the fifth embodiment, an abnormality of the secondary battery 62 is not included in the abnormality of the power storage device 50. Permission or prohibition of current interruption according to the fifth embodiment will be described with reference to Table 3 shown below. [Table 3]

[0123] When the number of power storage devices 50 with normal BMUs 100 is two or more, the vehicle ECU 31 permits current interruption to all of the power storage devices 50. Since current interruption is permitted to all of the power storage devices 50, if the BMU 100 of each power storage device 50 subsequently detects an abnormality in the BMU 100, the vehicle ECU 31 sets the current interruption device 53 to an interrupted state. This makes it possible to protect the power storage devices 50 from abnormalities.

[0124] When the number of power storage devices 50 whose BMU 100 is normal is one, the vehicle ECU 31 permits current interruption to the power storage device 50 whose BMU 100 is abnormal, while prohibiting current interruption to the one power storage device 50 whose BMU 100 remains normal until the end. For example, when the number of power storage devices 50 whose BMU 100 is normal is two, those power storage devices 50 are permitted to interrupt current. If the BMU 100 of one of the two power storage devices 50 subsequently becomes abnormal, the number of power storage devices 50 whose BMU 100 is normal becomes one, and therefore current interruption is prohibited for the one power storage device 50 whose BMU 100 remains normal until the end. By prohibiting current interruption to the one power storage device 50 whose BMU 100 remains normal until the end, the risk of power not being supplied to the mobile load can be reduced.

[0125] When the BMUs 100 of all the power storage devices 50 are abnormal, the vehicle ECU 31 prohibits current interruption for two or more power storage devices 50. In the fifth embodiment, since the number of the power storage devices 50 is two, as a result, current interruption is prohibited for all the power storage devices 50. For example, if the number of the power storage devices 50 is two and the BMU 100 of one of the two power storage devices 50 becomes abnormal, the number of power storage devices 50 whose BMU 100 is normal becomes one, so current interruption is prohibited for the one power storage device 50 that remains until the end as the power storage device 50 whose BMU 100 is normal. After that, if the BMU 100 of the one power storage device 50 that remains until the end as the power storage device 50 whose BMU 100 is normal also becomes abnormal, current interruption is prohibited for the one power storage device 50. As a result, current interruption is prohibited for two or more power storage devices 50. In other respects, embodiment 5 is substantially the same as embodiment 2, so a description thereof will be omitted.

[0126] According to the control method of the fifth embodiment, when the number of the power storage devices 50 with the normal BMU 100 is two or more, current interruption is permitted for all the power storage devices 50. Therefore, when the power storage device 50 has an abnormal BMU 100, the current is immediately interrupted, and when the power storage device 50 has a normal BMU 100, the current is interrupted when the power storage device 50 subsequently becomes abnormal. This ensures the safety of the power storage devices 50. When the BMU 100 of two power storage devices 50 is normal, if the BMU 100 of one of the power storage devices 50 subsequently becomes abnormal, there will be only one power storage device 50 with a normal BMU 100. When there is only one power storage device 50 with a normal BMU 100, the risk of power not being supplied to the mobile load can be reduced by prohibiting current interruption for the one power storage device 50 that remains as the power storage device 50 with the normal BMU 100 until the end.

[0127] <Other embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included within the technical scope of the present invention.

[0128] (1) In the above first embodiment, the power storage device 50 includes a plurality of secondary batteries 62. However, the power storage device 50 may include only one secondary battery 62. The power storage element is not limited to the secondary battery 62, but may be a capacitor or the like. Although power supply system 30 includes DC-DC converter 35, DC-DC converter 35 may be omitted. For example, if there is no difference between how first power storage device 50A and second power storage device 50B are used, there is little need to independently adjust the charging and discharging of second power storage device 50B, and DC-DC converter 35 may be omitted. When an adjustment device such as the DC-DC converter 35 is provided, the rated voltages of the two power storage devices 50 may be the same or different. The threshold voltage Va that switches first current interrupt device 53A of first power storage device 50A to the cut-off state and the threshold voltage Va that switches second current interrupt device 53B of second power storage device 50B to the cut-off state may be different.

[0129] (2) In the above-described first embodiment, the energy storage element (secondary battery 62), the current interruption device 53, and the BMU 100 are housed in the housing 71 of the energy storage device 50. The housing 71 only needs to house at least the energy storage element and the instruments, and the current interruption device 53 and the BMU 100 may be provided outside the housing 71.

[0130] (3) In the above-described first embodiment, when the emergency stop of the vehicle 10 is completed and the engine is stopped, the current interruption device 53 is turned off to prohibit the use of the power storage device 50. The timing for prohibiting the use of the power storage device 50 may be after a predetermined time has elapsed since the engine was stopped. By prohibiting the use of the power storage device 50 after the predetermined time has elapsed since the engine was stopped, it is possible to ensure time for notifying the outside that the vehicle 10 is in an emergency stop state by turning on hazard lamps, etc.

[0131] (4) In the above embodiment, an example has been described in which current cutoff is prohibited for two or more power storage devices 50 when all of the power storage devices 50 are abnormal. However, current cutoff may be prohibited for only one power storage device 50. This is because if current cutoff is prohibited for at least one power storage device 50, it is possible to prevent a situation in which power supply to the mobile load is cut off.

[0132] In the case where current cutoff is prohibited for one power storage device 50 when all of the power storage devices 50 become abnormal, it may be determined which power storage device 50 is to be prohibited from current cutoff based on the type of abnormality. In this case, each power storage device 50 transmits the type of abnormality to the vehicle ECU 31. Specifically, when the secondary battery 62 is abnormal, continued use of the power storage device 50 may cause the power storage device 50 to become completely unusable. In contrast, when the BMU 100 is abnormal, the secondary battery 62 is normal, so that the possibility of the power storage device 50 becoming completely unusable even if the power storage device 50 is continued to be used is relatively low.

[0133] For this reason, when one power storage device 50 has an abnormality in the secondary battery 62 and the other power storage device 50 has an abnormality in the BMU 100, the power storage device 50 with the abnormality in the secondary battery 62 may be permitted to be cut off, and the power storage device 50 with the abnormality in the BMU 100 may be prohibited from being cut off. In this way, it is possible to reduce the possibility that the power storage device 50 will become completely unusable, compared to when cut-off is prohibited for the power storage device 50 with the abnormality in the secondary battery 62.

[0134] Alternatively, the types of abnormalities of the power storage device 50 can be roughly divided into overcharge and other abnormalities. The other abnormalities include, for example, overdischarge, overcurrent, temperature abnormality, and abnormality of the BMU 100. If charging continues after overcharge, the time required for the overcharged power storage device 50 to reach a voltage at which it loses its battery performance is shorter than that required for the other abnormality. For this reason, when one power storage device 50 is overcharged and the other power storage device 50 is in an abnormality other than overcharge, the cutoff may be permitted for the overcharged power storage device 50, and the cutoff may be prohibited for the other abnormality. In this way, if charging continues, it can be accepted by the non-overcharged power storage device 50. By accepting the charge current by the non-overcharged power storage device 50, the time required for the power storage device 50 to reach a voltage at which it loses its battery performance is longer than that required for the overcharged power storage device 50 to receive the charging current, so that the time required for the vehicle 10 to be safely stopped can be secured.

[0135] When current cutoff is prohibited for two or more power storage devices 50 when all of the power storage devices 50 have become abnormal, it may be determined which power storage devices 50 to prohibit current cutoff from based on the type of abnormality. For example, assume that there are three power storage devices 50, one of which has an abnormality in the secondary battery 62 and the other two have an abnormality in the BMU 100. In this case, current cutoff may be prohibited for the two power storage devices 50 with the abnormality in the BMU 100. In this way, it is possible to reduce the possibility that the power storage devices 50 for which current cutoff is prohibited become completely unusable, compared to when the determination is made regardless of the type of abnormality.

[0136] (5) In the above embodiment, an abnormality in the current interruption device 53 is not included in the abnormality in the BMU 100. However, an abnormality in the BMU 100 may include an abnormality in the current interruption device 53.

[0137] (6) In the above embodiment, the power storage device 50 including a lithium ion battery has been described as an example of the power storage device. However, some of the multiple power storage devices may be lead-acid batteries. For example, when there are two power storage devices, one may be the power storage device 50 including a lithium ion battery and the other may be a lead-acid battery. Normally, a lead-acid battery is not provided with a current interrupting device 53 or a BMU 100. For this reason, in the case of a lead-acid battery, the current interrupting device 53 and a current sensor (or a voltage sensor) may be provided outside the lead-acid battery, and the vehicle ECU 31 may function as a BMU for the lead-acid battery. In this case, permitting or prohibiting the lead-acid battery from interrupting the current means that the vehicle ECU 31 permits or prohibits itself (the vehicle ECU 31 functioning as the BMU for the lead-acid battery) from interrupting the current interrupting device.

[0138] (7) In the above embodiment, the vehicle 10 (engine-driven vehicle) is exemplified as a moving body, but the moving body is not limited to an engine-driven vehicle. For example, the moving body may be an electric vehicle or a hybrid vehicle, or may be a forklift or an automatic guided vehicle (AGV) that runs on an electric motor. [Explanation of symbols]

[0139] 10 Vehicles (an example of a moving object) 21 Engine starting device (an example of a mobile load) 25 Electrical load (an example of a mobile load) 30 Power System 31 Vehicle ECU (an example of a control unit) 50A First power storage device (an example of a power storage device) 50B Second power storage device (an example of a power storage device) 50C Third power storage device (an example of a power storage device) 53A First current interrupter (an example of a current interrupter) 53B Second current interrupting device (an example of a current interrupting device) 62 Secondary battery (an example of a storage element) 100A First BMU (an example of a management device) 100B Second BMU (an example of a management device) 100C 3rd BMU (an example of a management device)

Claims

1. A method for controlling a power supply system of a moving body, comprising: the power supply system is connected to a mobile load and includes a plurality of power storage devices connected in parallel with each other; The energy storage device includes an energy storage element, a current interruption device connected in series with the energy storage element, and a management device, The control method includes: a first step of permitting or prohibiting current interruption for each of the power storage devices based on a combination of normal and abnormal states of each of the power storage devices so that the current interruption device of at least one of the power storage devices is in a conducting state; a second step of bringing the current interruption device into an interrupted state when the management device of the power storage device that has been permitted to interrupt the current detects an abnormality in the power storage device at the time when the management device detects an abnormality in the power storage device after ... Including, The first step comprises: prohibiting current interruption for each of the power storage devices when all of the power storage devices are normal; a step of requesting permission to cut off current when the management device of the power storage device detects an abnormality in the power storage device; when permission to interrupt a current is requested from the management device, permitting or prohibiting the power storage device that requested permission to interrupt the current to interrupt the current so that the current interruption device of at least one of the power storage devices is in an energized state based on a combination of normality and abnormality of each of the power storage devices; A method for controlling a power supply system of a mobile body, comprising:

2. A method for controlling a power supply system of a moving body, comprising: the power supply system is connected to a mobile load and includes a plurality of power storage devices connected in parallel with each other; The energy storage device includes an energy storage element, a current interruption device connected in series with the energy storage element, and a management device, The control method includes: a first step of permitting or prohibiting current interruption for each of the power storage devices based on a combination of normal and abnormal states of each of the power storage devices so that the current interruption device of at least one of the power storage devices is in a conducting state; a second step of bringing the current interruption device into an interrupted state when the management device of the power storage device that has been permitted to interrupt the current detects an abnormality in the power storage device at the time when the management device detects an abnormality in the power storage device after ... Including, In the first step, when two or more of the storage devices are normal, if it is assumed that one of the normal storage devices becomes abnormal and the current interruption device of that storage device is switched to an interrupted state, and the total remaining power of the other normal storage devices is less than the amount of power required for the power supply system, a control method for a power supply system of a mobile body prohibits current interruption for all of the normal storage devices.

3. A method for controlling a power supply system of a mobile body according to claim 1 or claim 2, comprising: A control method for a power supply system of a mobile body, in which, in the first step, when all of the power storage devices are abnormal, it is determined which of the power storage devices should be prohibited from cutting off current based on the type of abnormality in each of the power storage devices.

4. A power supply system for a mobile body, comprising: A plurality of power storage devices connected to a mobile load and connected in parallel to each other; A control unit; Equipped with The energy storage device includes an energy storage element, a current interruption device connected in series with the energy storage element, and a management device, a first process in which the control unit permits or prohibits current interruption for each of the power storage devices so that the current interruption device of at least one of the power storage devices is in a conducting state based on a combination of normality and abnormality of each of the power storage devices; a second process of bringing the current interruption device into an interrupted state when the management device of the power storage device that has been permitted to interrupt the current detects an abnormality in the power storage device at the time when the management device detects an abnormality in the power storage device after the current interruption is permitted; Run The first process includes: a process of prohibiting current interruption to each of the power storage devices when all of the power storage devices are normal; A process in which the management device of the power storage device requests permission to cut off current when the management device detects an abnormality in the power storage device; a process of permitting or prohibiting current interruption for the power storage device that has requested permission to interrupt the current, based on a combination of normal and abnormal states of each of the power storage devices, so that the current interruption device of at least one of the power storage devices is in an energized state, when permission to interrupt the current is requested from the management device; A power supply system for a mobile body comprising:

5. A power supply system for a mobile body, comprising: A plurality of power storage devices connected to a mobile load and connected in parallel to each other; A control unit; Equipped with The energy storage device includes an energy storage element, a current interruption device connected in series with the energy storage element, and a management device, a first process in which the control unit permits or prohibits current interruption for each of the power storage devices so that the current interruption device of at least one of the power storage devices is in a conducting state based on a combination of normality and abnormality of each of the power storage devices; a second process of bringing the current interruption device into an interrupted state when the management device of the power storage device that has been permitted to interrupt the current detects an abnormality in the power storage device at the time when the management device detects an abnormality in the power storage device after the current interruption is permitted; Run In the first processing, when two or more of the storage devices are normal, if it is assumed that one of the normal storage devices becomes abnormal and the current interruption device of that storage device is put into an interrupted state, and the total remaining power of the other normal storage devices is less than the amount of power required by the power supply system, the power supply system of a mobile body prohibits current interruption for all of the normal storage devices.

6. A power supply system for a mobile body, comprising: The power storage device is connected to a mobile load and includes a plurality of power storage devices connected in parallel with each other, The energy storage device includes an energy storage element, a current interruption device connected in series with the energy storage element, and a management device, any one of the management devices executes a first process for permitting or prohibiting current interruption for each of the power storage devices so that the current interruption device of at least one of the power storage devices is in a conducting state based on a combination of normality and abnormality of each of the power storage devices; the management device of the power storage device that has been permitted to interrupt the current executes a second process to set the current interruption device to an interrupted state when an abnormality in the power storage device is detected at the time when interruption of the current is permitted, or when an abnormality in the power storage device is detected after interruption of the current is permitted; The first process includes: a process of prohibiting current interruption to each of the power storage devices when all of the power storage devices are normal; A process in which the management device of the power storage device requests permission to cut off current when the management device detects an abnormality in the power storage device; a process of permitting or prohibiting current interruption for the power storage device that has requested permission to interrupt the current, based on a combination of normal and abnormal states of each of the power storage devices, so that the current interruption device of at least one of the power storage devices is in an energized state, when permission to interrupt the current is requested from the management device; A power supply system for a mobile body comprising:

7. A power supply system for a mobile body, comprising: The power storage device is connected to a mobile load and includes a plurality of power storage devices connected in parallel with each other, The energy storage device includes an energy storage element, a current interruption device connected in series with the energy storage element, and a management device, any one of the management devices executes a first process for permitting or prohibiting current interruption for each of the power storage devices so that the current interruption device of at least one of the power storage devices is in a conducting state based on a combination of normality and abnormality of each of the power storage devices; the management device of the power storage device that has been permitted to interrupt the current executes a second process to set the current interruption device to an interrupted state when an abnormality in the power storage device is detected at the time when interruption of the current is permitted, or when an abnormality in the power storage device is detected after interruption of the current is permitted; In the first processing, when two or more of the storage devices are normal, if it is assumed that one of the normal storage devices becomes abnormal and the current interruption device of that storage device is put into an interrupted state, and the total remaining power of the other normal storage devices is less than the amount of power required by the power supply system, the power supply system of a mobile body prohibits current interruption for all of the normal storage devices.

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