Power supply device

Abstract

This power supply device is provided with: a plurality of battery packs (10) that are connected in parallel to a piece of external equipment (2); and a control device (9) that communicates with the plurality of battery packs. Each battery pack comprises: a plurality of battery cells (11a, 11b); and a monitoring device (13) that detects the state of the battery cells and controls an electrical connection with the external equipment in accordance with the state of the battery, in cooperation with the control device. The monitoring device grasps a subject number, which is the number of subject battery packs (10d), the subject battery packs being the battery packs that are electrically connected to the external equipment after control is performed. In accordance with the subject number, subject monitoring devices (13d), which are the monitoring devices included in the subject battery packs, each determine a fail-safe for a case in which an abnormality subsequently occurs in the battery cells included in the subject battery pack.

Description

power supply CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2024-001489 filed in Japan on January 9, 2024, and the contents of the original application are incorporated by reference in their entirety.

[0002] The disclosure herein relates to a power supply.

[0003] The power supply system described in Patent Document 1 includes a vehicle ECU, a first power storage device, and a second power storage device. The vehicle ECU is connected to the first power storage device and the second power storage device so as to be able to communicate with each other. The first power storage device includes a first current interruption device, a first assembled battery, and a first BMU. The second power storage device includes a second current interruption device, a second assembled battery, and a second BMU.

[0004] When there are normal and abnormal power storage devices, the vehicle ECU allows current to be cut off to the abnormal power storage device. This allows the vehicle to continue supplying power to the vehicle using the other power storage device even if an abnormality occurs in one power storage device, providing redundancy to the vehicle's power supply. Furthermore, when all power storage devices are abnormal, the vehicle ECU prohibits current cutoff to two or more power storage devices. This ensures time for the vehicle to stop safely.

[0005] Japanese Patent Application Laid-Open No. 2021-166434

[0006] In the configuration of Patent Document 1, the supply and cut-off of current to each power storage device is controlled based on a combination of normal and abnormal states of each power storage device so that at least one power storage device is in a powered state. In the configuration of Patent Document 1, the fail-safe is determined to be current cut-off, and it is not possible to determine the fail-safe depending on the number of battery packs currently connected to the external device.

[0007] Therefore, an object of the present disclosure is to provide a power supply device that can determine a fail-safe mode depending on the number of battery packs electrically connected to an external device.

[0008] A power supply device according to one aspect of the present disclosure comprises: a plurality of battery packs connected in parallel to an external device; and a control device that communicates with the plurality of battery packs, wherein the battery packs each have a plurality of battery cells; and a monitoring device that detects the state of the battery cells and controls electrical connection with the external device in cooperation with the control device according to the state of the battery cells, wherein the monitoring device determines the target number, which is the number of target battery packs that are battery packs electrically connected to the external device after control is performed, and a target monitoring device, which is a monitoring device included in the target battery pack, determines a fail-safe in the event that an abnormality subsequently occurs in a battery cell included in the target battery pack, according to the target number.

[0009] Depending on the number of target battery packs, which are battery packs electrically connected to external devices, the target monitoring devices included in the target battery packs can determine the subsequent fail-safe.

[0010] It should be noted that the reference numbers in parentheses in the appended claims merely indicate the corresponding relationship with the configurations described in the embodiments described below, and do not in any way limit the technical scope.

[0011] It is a block diagram showing a power system including a power supply device according to a first embodiment. It is a flowchart explaining a fail-safe of the power supply device. It is a flowchart explaining a fail-safe of the power supply device. It is a block diagram showing a power system including a power supply device according to a second embodiment.

[0012] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment will be assigned the same reference numerals, and duplicated explanations may be omitted. In each embodiment, when only a part of the configuration is described, the other previously described embodiments may be applied to the other parts of the configuration.

[0013] In addition, it is not only possible to combine parts that are explicitly stated as being possible in each embodiment, but it is also possible to partially combine embodiments, embodiments and variants, and variants even if not explicitly stated, as long as there are no particular problems with the combination.

[0014] First Embodiment FIG. 1 is a block diagram showing a power system 1 including a power supply device 3 according to a first embodiment. As an example, the power system 1 is mounted on a vehicle and supplies power for running the vehicle. However, the power system 1 is not limited to being mounted on a vehicle. Other examples of the power system 1 include mobile computing devices such as mobile phones, laptop computers, and tablet computers. Alternatively, as another example, the power system 1 may be mounted on portable multimedia devices including digital cameras, video cameras, audio / video playback devices, and the like.

[0015] The following description will mainly focus on an example in which the power system 1 is mounted on a vehicle. The power system 1 includes an electric motor mechanism 2 that supplies power to drive wheels to propel the vehicle. The electric motor mechanism 2 may include an inverter circuit 2a, a rotating electric machine 2b such as a generator motor, a power transmission device such as a transmission, and the vehicle's drive wheels. The electric motor mechanism 2 is mounted on the vehicle as the main power unit of an electric vehicle or as a power unit alongside the internal combustion engine of a hybrid vehicle. The electric motor mechanism 2 may also be referred to as an external device. In the drawings, the inverter circuit 2a is indicated as INV, and the rotating electric machine 2b is indicated as MG.

[0016] The power system 1 includes a power supply device 3 that supplies DC power to an electric mechanism 2. The power supply device 3 includes a battery pack 4 that uses the electric mechanism 2 as a load. The power supply device 3 also includes a control device 9 that controls the electric mechanism 2 and the power supply device 3. The power system 1 includes the power supply device 3 and the electric mechanism 2. The control device 9 is indicated as an ECU in the drawings.

[0017] The control device 9 controls the electric mechanism 2 so as to properly drive the vehicle. The control device 9 is also a control device for controlling the battery pack 4. For example, the control device 9 controls a plurality of relays, described below, when the power system 1 is started and stopped in order to control the power supply to the electric mechanism 2. The control device 9 provides a drive control method for controlling the electric mechanism 2 in accordance with the state of charge of the battery pack 4. The control device 9 charges the battery pack 4 by causing the electric mechanism 2 to function as a generator. Alternatively, the control device 9 provides a charge control method for controlling the power supply device 3 when the battery pack 4 is charged from an external power source.

[0018] The control device 9 is electrically connected to a rotating electric machine control device 2c of the electric mechanism 2 to control the inverter circuit 2a and the rotating electric machine 2b of the electric mechanism 2. The control device 9 is also electrically connected to monitoring devices 13 for the multiple battery packs 10 included in the battery pack 4. The electrical connection between the control device 9 and the multiple monitoring devices 13 is provided by a network connection that enables information communication. The rotating electric machine control device 2c is indicated as MGECU in the drawings.

[0019] The control device 9 and the monitoring device 13 are control devices that operate by receiving power from a low-voltage secondary battery installed in the vehicle. The control device 9 and / or the monitoring device 13 are provided by a microcomputer that includes a computer-readable storage medium. The storage medium stores a computer-readable program. The storage medium may be provided by a memory.

[0020] The programs are executed by the control device 9 and / or the monitoring device 13 to cause them to function as devices. The programs also cause the control device 9 and / or the monitoring device 13 to function to perform the control methods described in this specification. The methods provided by the control device 9 and / or the monitoring device 13 can also be called functional blocks or modules that achieve predetermined functions.

[0021] The battery pack 4 includes a plurality of battery packs 10. In the figure, a plurality of battery packs 10a, 10b, and 10c are shown as an example. In the following description, the reference numerals 10a, 10b, and 10c are used to refer to a specific battery pack, and the reference numeral 10 is used to refer to any battery pack. The plurality of battery packs 10 are connected in parallel to a load. The battery packs 10a, 10b, and 10c all have the same configuration.

[0022] The battery pack 10 includes a battery 11, a first power supply relay 12a, a second power supply relay 12b, and a monitoring device 13. The battery 11 is a large-capacity, high-voltage secondary battery that can function as a power source for driving the vehicle. The battery 11 can be provided by a lithium-ion battery that supplies a voltage of several hundred volts. The battery 11 has multiple battery cells.

[0023] In the figure, a plurality of battery cells 11a and 11b are shown as an example. The battery cell 11a and the battery cell 11b are connected in series. The positive electrode of the battery cell 11a is electrically connected to the positive electrode of the electric mechanism 2. The negative electrode of the battery cell 11a is electrically connected to the positive electrode of the battery cell 11b. The negative electrode of the battery cell 11b is electrically connected to the negative electrode of the electric mechanism 2.

[0024] The first power supply relay 12a is provided between the positive electrode of the battery cell 11a of each battery pack 10a, 10b, 10c and the electric mechanism 2. The first power supply relay 12a is a system relay on the positive electrode side of the power supply device 3. The second power supply relay 12b is provided between the negative electrode of the battery cell 11b of each battery pack 10a, 10b, 10c and the electric mechanism 2. The second power supply relay 12b is a system relay on the negative electrode side of the power supply device 3. The power supply relays 12a, 12b connect and disconnect the connection between the battery 11 and the electric mechanism 2.

[0025] The monitoring device 13 detects the status of the battery 11 in the battery pack 10 in which it is included, and controls the opening and closing of the power supply relays 12a, 12b. Note that one monitoring device 13 may monitor multiple battery packs 10. The monitoring device 13 detects the status of the battery pack 10, such as the voltage, current, and temperature. Based on the detected status, the monitoring device 13 can determine whether the battery 11 being monitored is normal or abnormal. Abnormalities in the battery 11 include overcharging, over-discharging, and temperature abnormalities. Status information for each battery pack 10 is transmitted from each monitoring device 13 to the control device 9. The status information is information on whether the battery 11 is in a normal state or an abnormal state.

[0026] In response, the control device 9 transmits control instructions to the power supply relays 12a and 12b to each monitoring device 13. As an example, the control instruction is an instruction to permit electrical conduction between the battery pack 10 including the normal battery 11 and the electric mechanism 2 when the state of the battery 11 is normal. As another example, the control instruction is an instruction to cut off electrical conduction between the battery pack 10 including the abnormal battery 11 and the electric mechanism 2 when the state of the battery 11 is abnormal. As another example, the control instruction is a control instruction issued when there is a voltage variation among the battery packs 10a, 10b, and 10c. Specifically, the control instruction is an instruction to cut off electrical conduction between the electric mechanism 2 and a battery pack 10 whose voltage significantly deviates from the average voltage.

[0027] The monitoring device 13 can control the power supply relays 12a, 12b to cut off current to the electric mechanism 2 when the battery pack 10 is abnormal or the voltage is significantly different from the average value. As described above, the battery 11 has multiple battery cells 11a, 11b connected in series. The performance and characteristics of these multiple battery cells 11a, 11b differ from one another due to product variations. Therefore, repeated charging and discharging causes the SOC of each of the multiple battery cells 11a, 11b to differ. Due to their nature, the battery cells 11a, 11b must be prevented from over-discharging and over-charging. In other words, over-discharging and over-charging are extreme drops and rises in the SOC.

[0028] Variations in the SOC of each battery cell 11a, 11b mean that the degree to which each battery cell 11a, 11b reaches over-discharge and over-charge also varies. In order to accurately control the SOC of the battery 11 so that it does not reach over-discharge and over-charge, it is necessary to equalize the SOC of the multiple battery cells 11a, 11b. In other words, it is necessary to make the SOC of each of the multiple battery cells 11a, 11b match the SOC of the battery 11, which is the sum average of these SOCs. Due to this requirement, the monitoring device 13 performs equalization processing of the battery cells 11a, 11b in addition to the fail-safe processing described below.

[0029] The control results of the power supply relays 12a, 12b by the monitoring device 13 are transmitted to the control device 9. In response to the control results, the control device 9 transmits information on the number of battery packs 10 currently electrically connected to the electric mechanism 2 to the monitoring device 13 of each battery pack 10. A battery pack 10 that is still electrically connected to the electric mechanism 2 even after the monitoring device 13 controls the power supply relays 12a, 12b may be referred to as a target battery pack 10d. A monitoring device 13 included in a target battery pack 10d may be referred to as a target monitoring device 13d. Information on the number of target battery packs 10d may be referred to as target number information.

[0030] As described above, the monitoring device 13 can determine whether the battery 11 being monitored is normal or abnormal. The target monitoring device 13d determines that the battery 11 included in the target battery pack 10d is normal. Target number information is also sent to the target monitoring device 13d from the control device 9. The target monitoring device 13d is configured to be able to determine the subsequent fail-safe action based on the target number information.

[0031] The monitoring device 13 is programmed with a fail-safe program that, if the number of target battery packs is equal to or less than a predetermined number, restricts the operation of the target battery pack 10d if an abnormality subsequently occurs in the target battery pack 10d. The monitoring device 13 is also programmed with a fail-safe program that, if the number of target battery packs is greater than the predetermined number, electrically disconnects only the target battery pack 10d in which the abnormality occurred from the electric mechanism 2 if an abnormality subsequently occurs in the target battery pack 10d. The predetermined number is, for example, 1. The predetermined number is not limited to 1. The predetermined number may be 2 or more.

[0032] When electrically disconnecting the target battery pack 10d in which an abnormality has occurred from the electric mechanism 2, a limiting signal that limits the output of the rotating electric machine 2b is transmitted from the control device 9 to the rotating electric machine control device 2c before disconnection. The rotating electric machine control device 2c limits the output of the rotating electric machine 2b based on the limiting signal. This makes it possible to reduce the amount of current required for the current path between the battery pack 10 and the electric mechanism 2. As a result, the target battery pack 10d in which an abnormality has occurred can be safely disconnected from the electric mechanism 2.

[0033] Furthermore, as a fail-safe measure when the number of target batteries is below a predetermined number, a method of limiting charging of the batteries 11 is adopted. For example, while the vehicle is running, the electric motor mechanism 2 functions as a generator, prohibiting charging of the battery pack 4. Charging gradually increases the SOC of the battery pack 10. By limiting charging before overcharging occurs, the time until the target battery pack 10d reaches a voltage at which it loses its battery performance is extended. This ensures time until the vehicle can be safely stopped.

[0034] Another fail-safe measure when the number of target battery packs is equal to or less than a predetermined number is to limit the discharge from the target battery pack 10d. Discharging gradually reduces the SOC of the battery pack 10. Limiting the discharge of the target battery pack 10d when the number of target battery packs is equal to or less than a predetermined number suppresses the reduction in SOC of the target battery pack 10d. This ensures time until the vehicle can be stopped safely.

[0035] The monitoring device 13 controls the amount of power flowing in and out of the target battery pack 10d by setting a threshold value to prevent the SOC of the target battery pack 10d from being overcharged or overdischarged. As an example, the monitoring device 13 measures the current value at regular intervals and estimates the SOC using the current integration method. The current integration method measures the amount of power flowing in and out of the battery 11 by constantly measuring the charging and discharging current of the battery 11. The SOC is then estimated by adding or subtracting this from the initial capacity. The monitoring device 13 determines that the estimated SOC or battery cell voltage is overcharged if it is greater than a predetermined upper limit, and that it is overdischarged if it is less than a predetermined lower limit.

[0036] The monitoring device 13 also has a timer that measures the time during which charging and discharging are occurring. The monitoring device 13 determines whether the measured time indicated by the timer has exceeded a preset time limit. By controlling the power input and output to and from the battery 11 before the measured time exceeds the time limit, the monitoring device 13 can ensure sufficient time for the vehicle to be safely stopped.

[0037] The electric mechanism 2 also has the function of generating electricity using at least one of the rotational energy of the engine and the rotational energy of the wheels. The rotating electric machine 2b generates AC voltage by power generation. This AC voltage is converted to DC voltage by an inverter. This DC voltage is supplied to the battery pack 10 and each of the electrical loads.

[0038] Electrical loads include general loads and protective loads that are more closely related to vehicle operation than the general loads. General loads include vehicle-mounted devices such as seat heaters, ventilation fans, electric compressors, interior lights, and headlights. These general loads do not require a constant supply of power. The amount of power required by the general loads fluctuates depending on the operation of the vehicle user, etc.

[0039] The protected loads include an electric shift positioner, electric power steering (EPS), brakes (ABS), door locks, a navigation system, and audio. These protected loads require a constant supply of power. The protected loads have the property of switching from an ON state to an OFF state when the supply voltage falls below a threshold voltage. The amount of power required by the protected loads is always above a certain amount so that they can respond to changes in vehicle driving.

[0040] The main purpose of controlling the opening and closing of the power supply relays is to supply power to the rotating electric machine. When the power system 1 is in a driving state, the monitoring device 13 controls the power supply relays 12a and 12b based on a command signal from the control device 9. The target monitoring device 13d controls the opening and closing of the power supply relays 12a and 12b based on the driving state of the rotating electric machine 2b and the SOC of the battery pack 10. The target monitoring device 13d controls the opening and closing of the power supply relays 12a and 12b so that the supply voltage to the protected load does not fall below a threshold voltage. This reduces the risk of power being cut off to the protected load.

[0041] The fail-safe function of the power supply device 3 will be described below with reference to Figure 2. The startup process is executed, for example, when the vehicle power supply is turned on and the control device 9 starts control to run the vehicle. In step S10, each monitoring device 13 detects the status of the battery 11, such as voltage, current, and temperature, and determines whether each battery pack 10 is normal or abnormal. The status of each battery pack 10 determined in step S10 is transmitted from each monitoring device 13 to the control device 9.

[0042] In step S20, the control device 9 distinguishes between battery packs 10 in a normal state and battery packs 10 in an abnormal state, and outputs different control signals to each. For battery packs 10 determined to be normal in step S20, the control device 9 sends a signal to the monitoring device 13 to close the power supply relays 12a and 12b in step S30. In step S30, the monitoring device 13 performs processing to close the power supply relays 12a and 12b for battery packs 10 determined to be normal. For battery packs 10 determined to be abnormal in step S20, the control device 9 sends a signal to the monitoring device 13 to open the power supply relays 12a and 12b in step S40. In step S40, the monitoring device 13 performs processing to open the power supply relays 12a and 12b for battery packs 10 determined to be abnormal.

[0043] Next, in step S50, the control device 9 counts the number of battery packs 10 that are currently electrically connected to the electric mechanism 2. The number of electrically connected battery packs 10 refers to the number of battery packs 10 for which both power supply relays 12a and 12b in FIG. 1 are in the connected state. The information on the number of battery packs counted in step S50 is transmitted to each monitoring device 13. In step S60, the target monitoring device 13d determines whether the number of battery packs 10 is greater than a predetermined number.

[0044] If it is determined in step S60 that the number of target battery packs 10d is equal to or less than the predetermined number, the target monitoring device 13d restricts the operation of the target battery packs 10d as a fail-safe for the target battery packs 10d thereafter in step S80. If it is determined in step S60 that the number of target battery packs 10d is greater than the predetermined number, the target monitoring device 13d electrically disconnects the target battery packs 10d from the electric mechanism 2 as a fail-safe for the target battery packs 10d thereafter in step S70. Note that in both steps S70 and S80, the above fail-safe is applied only to target battery packs 10d in which an abnormality subsequently occurs. If an abnormality subsequently occurs in some of the target battery packs 10d in step S70, only the target battery packs 10d in which an abnormality occurred are electrically disconnected from the electric mechanism 2. Target battery packs 10d that are not experiencing an abnormality remain electrically connected to the electric mechanism 2. Furthermore, if an abnormality subsequently occurs in all of the target battery packs 10d in step S70, none of the target battery packs 10d are electrically disconnected from the electric mechanism 2. At least one of the target battery packs 10d is kept electrically connected to the electric mechanism 2. The power supply device 3 starts the above-described flow again from step S70 or step S80 to END. The above-described flow is repeated until the vehicle power is turned off and the control device 9 performs control to stop the vehicle.

[0045] In step S10, each monitoring device 13 may determine whether the voltage of each battery pack 10 significantly deviates from the average value, instead of determining the state of each battery pack 10. The fail-safe of the power supply device 3 will be described with reference to Fig. 3. In step S20, the control device 9 distinguishes between battery packs 10 that significantly deviate from the average value and other battery packs 10, and outputs different control signals to each of them.

[0046] For battery packs 10 that are identified in step S20 as not significantly deviating from the average value, the control device 9 sends a signal to close the power supply relays 12a and 12b in step S30. For battery packs that are identified in step S20 as significantly deviating from the average value, the control device 9 sends a signal to open the power supply relays 12a and 12b in step S40. Note that the flow from step S50 onwards is similar and therefore will not be described here.

[0047] <Effects> The power supply device 3 has a plurality of battery packs 10 and a control device 9. The plurality of battery packs 10 are connected in parallel to the electric mechanism 2. The control device 9 communicates with the plurality of battery packs 10. Each battery pack 10 has a battery 11 and a monitoring device 13. The monitoring device 13 detects the state of the battery 11. The monitoring device 13 cooperates with the control device 9 to control the electrical connection with the electric mechanism 2 according to the state of the battery 11. The monitoring device 13 further grasps the target number, which is the number of target battery packs. Depending on the target number, the target monitoring device determines a fail-safe in the event that an abnormality subsequently occurs in a battery 11 included in the target battery pack 10d. The target monitoring device can determine subsequent fail-safes according to the number of target battery packs.

[0048] The target monitoring device restricts the operation of the target battery packs if the number of target battery packs is below a predetermined number and an abnormality subsequently occurs in a battery 11 included in the target battery pack, thereby reducing the risk of power being cut off to the electric mechanism 2 when the number of target battery packs is below the predetermined number.

[0049] If the number of target battery packs exceeds a predetermined number and an abnormality subsequently occurs in a battery 11 included in the target battery pack, the target monitoring device electrically disconnects only the target battery pack in which the abnormality occurred from the electric mechanism 2. Even if the number of target battery packs exceeds a predetermined number, the risk of power being cut off to the electric mechanism 2 can be reduced.

[0050] As a fail-safe measure in the event that the number of target battery packs exceeds a predetermined number, after restricting the current flow between the battery packs 10 and the electric mechanism 2, the target monitoring device electrically disconnects only the target battery pack in which an abnormality has occurred from the electric mechanism 2. When electrically disconnecting the target battery pack from the electric mechanism 2, a limiting signal that limits the output of the rotating electric machine 2b is sent from the control device 9 to the rotating electric machine control device 2c before disconnection. The rotating electric machine control device 2c limits the output of the rotating electric machine 2b based on the limiting signal. This makes it possible to reduce the amount of current required for the current path between the battery packs 10 and the electric mechanism 2. Therefore, the target battery pack in which an abnormality has occurred can be safely disconnected from the electric mechanism 2.

[0051] As a fail-safe measure when the number of target battery packs is below a predetermined number, the target monitoring device limits charging of the target battery pack. For example, charging from the electric mechanism 2 to the battery pack 4 while the vehicle is moving is prohibited. By limiting charging before the target battery pack becomes overcharged, the time until the target battery pack reaches a voltage at which it loses battery performance is extended, ensuring time to safely stop the vehicle.

[0052] As another fail-safe measure when the number of target battery packs is below a predetermined number, the target monitoring device limits discharge to the target battery pack. By limiting discharge to the target battery pack, the decrease in SOC of the target battery pack is suppressed, and time is secured until the vehicle can be stopped safely.

[0053] The fail-safe when the number of target battery packs is below a predetermined number is implemented according to the SOC, voltage, or time limit of the target battery packs. For example, the target monitoring device controls the amount of power input and output by setting a threshold to prevent the SOC of the target battery pack from being overcharged. The target monitoring device also sets a threshold to limit the amount of power input and output by setting a threshold to prevent the SOC of the target battery pack from being overdischarged.

[0054] The monitoring device 13 controls the power supply relays 12a and 12b based on a command signal from the control device 9. The target monitoring device controls the opening and closing of the power supply relays 12a and 12b based on the driving state of the rotating electric machine 2b, etc. The target monitoring device controls the opening and closing of the power supply relays 12a and 12b so that the voltage supplied to the rotating electric machine 2b does not fall below a threshold voltage. This can reduce the risk of power being cut off to the electric mechanism 2.

[0055] The monitoring device 13 also has a timer that measures the time during which charging and discharging are occurring. The monitoring device 13 determines whether the measured time indicated by the timer has exceeded a preset time limit. Before the measured time exceeds the time limit, the monitoring device 13 switches the battery pack 10 to limited operation by controlling the power input and output to the battery 11. This also ensures that the vehicle has enough time to stop safely.

[0056] Second Embodiment In the first embodiment, the battery pack 4 includes a plurality of battery packs 10 each including the same components. Each of the plurality of battery packs 10 in the first embodiment includes a battery 11, a first power supply relay 12 a, a second power supply relay 12 b, and a monitoring device 13.

[0057] Each monitoring device 13 in the first embodiment detects the state of the battery 11 and controls the power supply relays 12a, 12b. The status of the battery 11 in each battery pack 10 is transmitted from each monitoring device 13 to the control device 9. In response to this, the control device 9 transmits a control instruction for the power supply relays 12a, 12b to each monitoring device 13. The control results of the power supply relays 12a, 12b by the monitoring device 13 are transmitted to the control device 9. In response to the control results, the control device 9 counts the number of battery packs 10 currently connected to the electric mechanism 2.

[0058] The control device 9 transmits information on the number of battery packs 10 currently connected to the electric mechanism 2 to the monitoring device 13 of each battery pack 10. The target monitoring device 13d is configured to be able to determine the subsequent fail-safe in accordance with the target number information.

[0059] In contrast, in the second embodiment, the assembled battery 4 has a plurality of battery packs 10 including different components. Figure 4 is a block diagram showing a power system including a power supply device 3 in the second embodiment. The plurality of battery packs 10 in the second embodiment have a first battery pack 10e that is the same as in the first embodiment, and a second battery pack 10f that has a different type of monitoring device 13 from that in the first embodiment. The monitoring device 13 in the second battery pack 10f is a central monitoring device 13f that oversees information transmitted from the monitoring devices 13 provided in the first battery pack 10e.

[0060] Each monitoring device 13 in the second embodiment detects the state of the battery 11 and controls the power supply relays 12a and 12b. Each monitoring device 13e included in the first battery pack 10e transmits state information of the battery 11 in the first battery pack 10e to the central monitoring device 13f. In response to this, the central monitoring device 13f transmits a control instruction for the power supply relays 12a and 12b to the monitoring device 13e of the first battery pack 10e. The central monitoring device 13f detects the state information included in its own second battery pack 10f and controls the power supply relays 12a and 12b based on the state information.

[0061] The control results of the power supply relays 12a and 12b by the monitoring device 13e are transmitted to the central monitoring device 13f. In response to the control results, the central monitoring device 13f counts the number of battery packs 10 currently connected to the electric mechanism 2. Information on the number of battery packs 10 currently connected to the electric mechanism 2 is transmitted from the central monitoring device 13f to the monitoring device 13e of the first battery pack 10e. The target monitoring device 13d can determine a subsequent fail-safe based on the target number information. While the diagram shows a configuration in which the battery pack 10a has the central monitoring device 13f and the battery packs 10b and 10c have the target monitoring device 13d, this is not limiting. When the central monitoring device 13f itself is the target battery pack 10d, it determines a subsequent fail-safe based on the target number information it has.

[0062] In this way, in the second embodiment, at least the function of tallying the target number information and the function of transmitting the target number information to each monitoring device 13, which are possessed by the control device 9 in the first embodiment, are transferred to the central monitoring device 13f, thereby achieving the same effects as in the first embodiment.

[0063] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, although various combinations and forms are shown in the present disclosure, other combinations and forms including only one element, more, or less than one element are also within the scope and spirit of the present disclosure.

[0064] (Disclosure of Technical Ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be described in a multiple dependent form, where the subsequent clause alternatively refers to the preceding clause. Some clauses may be described in a multiple dependent form, where the subsequent clause refers to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0065] (Technical Idea 1) A power supply device comprising: a plurality of battery packs (10) connected in parallel to an external device (2); and a control device (9) that communicates with the plurality of battery packs, wherein the battery packs have a plurality of battery cells (11a, 11b); and a monitoring device (13) that detects the state of the battery cells and controls electrical connection with the external device in accordance with the state of the battery cells in cooperation with the control device, wherein the monitoring device grasps the target number, which is the number of target battery packs (10d) that are the battery packs electrically connected to the external device after the control is performed, and a target monitoring device (13d), which is the monitoring device included in the target battery pack, determines a fail-safe in the event that an abnormality subsequently occurs in the battery cells included in the target battery pack, in accordance with the target number.

[0066] (Technical Idea 2) When the number of target battery packs is less than a predetermined number, the target monitoring device is configured to limit the operation of the target battery packs as a fail-safe, if an abnormality subsequently occurs in a battery cell included in the target battery pack. This is the power supply device described in Technical Idea 1.

[0067] (Technical Idea 3) When the number of target battery packs is greater than the predetermined number, if an abnormality subsequently occurs in a battery cell included in the target battery pack, the target monitoring device electrically disconnects only the target battery pack in which an abnormality has occurred in the battery cell from the external device as a fail-safe, in accordance with Technical Idea 2.

[0068] (Technical Idea 4) A power supply device according to Technical Idea 3, in which after the flow of current between the battery pack and the external device is restricted, the target monitoring device electrically disconnects only the target battery pack in which an abnormality has occurred in the battery cell from the external device.

[0069] (Technical Concept 5) The power supply device according to Technical Concept 2, wherein the target monitoring device limits charging of the target battery pack as the fail-safe.

[0070] (Technical Concept 6) The power supply device according to Technical Concept 2 or 5, wherein the target monitoring device limits discharge of the target battery pack as the fail-safe.

[0071] (Technical Concept 7) The power supply device according to Technical Concept 5 or 6, wherein the fail-safe is performed in response to an SOC of the target battery pack, a voltage of the target battery pack, or a preset time limit.

[0072] (Technical Idea 8) A power supply device according to any one of Technical Ideas 1 to 7, wherein the target monitoring device determines the fail-safe in the event that an abnormality subsequently occurs in the battery cell included in the target battery pack, depending on the number of targets sent from the control device.

[0073] (Technical Idea 9) A power supply device according to any one of Technical Ideas 1 to 7, wherein one of the plurality of battery packs is a monitoring device that functions as a master monitoring device (13f) that oversees the monitoring devices included in the remaining battery packs and keeps track of the number of target items, and the target monitoring devices other than the master monitoring device determine the fail-safe in the event that an abnormality subsequently occurs in a battery cell included in the target battery pack, depending on the number of target items sent from the master monitoring device.

Claims

1. A power supply device comprising: a plurality of battery packs (10) connected in parallel to an external device (2); and a control device (9) communicating with the plurality of battery packs, wherein each battery pack includes: a plurality of battery cells (11a, 11b); and a monitoring device (13) that detects the state of the battery cells and controls the electrical connection with the external device in cooperation with the control device according to the state of the battery cells, the monitoring device grasps the target number which is the number of target battery packs (10d) electrically connected to the external device after the control is performed, and the target monitoring device (13d) which is the monitoring device included in the target battery pack determines a fail-safe when an abnormality occurs in the battery cells included in the target battery pack according to the target number.

2. The power supply device according to claim 1, wherein when the number of the target battery packs is less than or equal to a predetermined number, the target monitoring device restricts the operation of the target battery pack as the fail-safe when an abnormality occurs in the battery cells included in the target battery pack.

3. The power supply device according to claim 2, wherein when the number of the target battery packs is more than the predetermined number, the target monitoring device electrically disconnects only the target battery pack in which an abnormality has occurred in the battery cells from the external device as the fail-safe when an abnormality occurs in the battery cells included in the target battery pack.

4. The power supply device according to claim 3, wherein after the energization between the battery pack and the external device is restricted, the target monitoring device electrically disconnects only the target battery pack in which an abnormality has occurred in the battery cells from the external device.

5. The power supply device according to claim 2, wherein as the fail-safe, the target monitoring device restricts the charging of the target battery pack.

6. The power supply device according to claim 2, wherein as the fail-safe, the target monitoring device restricts the discharging of the target battery pack.

7. The power supply device according to claim 5 or 6, wherein the fail-safe is performed according to the state of charge (SOC) of the target battery pack, the voltage of the target battery pack, or a preset limit time.

8. The target monitoring device according to any one of claims 1 to 6, which determines the fail-safe in the case where an abnormality occurs in the battery cells included in the target battery pack thereafter, according to the number of targets sent from the control device.

9. One of the plurality of battery packs is a monitoring device that functions as an overall monitoring device (13f) that oversees the monitoring devices included in the remaining battery packs and grasps the number of targets, and the target monitoring device excluding the overall monitoring device determines the fail-safe in the case where an abnormality occurs in the battery cells included in the target battery pack thereafter, according to the number of targets sent from the overall monitoring device. The power supply device according to any one of claims 1 to 6.

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