vehicle

Abstract

To provide a vehicle that includes a detachable battery and performs appropriate electric leakage detection.SOLUTION: An ECU executes: a step (S100) of obtaining a resistance value of insulation resistance; a step (S106) of determining that electric leakage occurs in a battery pack whose resistance value is equal to or less than a threshold α when the resistance value is equal to or less than the threshold α (NO in S102); a step (S112) of turning on each SMR when the resistance value is greater than the threshold α (YES in S102); a step (S114) of obtaining the resistance value of the insulation resistance; and a step (S120) of determining that electric leakage occurs in a vehicle body when the resistance value is equal to or less than the threshold α (NO in S116).SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to vehicles with removable batteries. [Background technology]

[0002] Japanese Patent Publication No. 2020-523576 (Patent Document 1) discloses a leakage detection device that detects leakage using an insulation resistance value that indicates the state of insulation between a battery and ground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2020-523576 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned leakage detection device is not designed for vehicles equipped with detachable batteries, and therefore is not designed to detect leakage according to the battery's detachment state, and may not be able to perform appropriate leakage detection.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a vehicle equipped with a removable battery that performs appropriate leakage detection. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, a vehicle includes a vehicle body, a battery detachable from the vehicle body, and a detection device provided in the battery for detecting the presence or absence of a leakage current, the detection device detecting the presence or absence of the leakage current when the battery is in at least one of a conductive state in which the battery is connected to an electrical circuit of the vehicle body and a disconnected state in which the battery is disconnected from the electrical circuit.

[0007] In this way, the presence or absence of a leakage current can be detected when the battery and the electrical circuit on the vehicle body side are in a conductive or disconnected state, making it possible to accurately determine whether the cause of the leakage current is due to the electrical circuit on the vehicle body side or the battery.

[0008] In one embodiment, the detection device detects the presence or absence of a battery leakage when in a disconnected state, and if no leakage is detected, detects the presence or absence of a leakage when in a conductive state.

[0009] This allows the presence or absence of a battery leakage to be detected when the circuit is in the cutoff state. Furthermore, if no battery leakage is detected, the presence or absence of a leakage in the vehicle's electrical circuit can be detected when the circuit is in the conductive state.

[0010] In one embodiment, the vehicle body is configured to accommodate a plurality of batteries, and when each of the plurality of batteries is connected to the electric circuit and in a conductive state, the presence or absence of a leakage current is detected by one of the plurality of detection devices.

[0011] In this way, interference in the detection of electric leakage between a plurality of detection devices is suppressed, and electric leakage can be detected with high accuracy.

[0012] In one embodiment, the vehicle body is configured to accommodate a plurality of batteries, and when each of the plurality of batteries is in a disconnected state where it is disconnected from the electrical circuit, the detection device of each of the plurality of batteries detects whether or not there is a leakage current.

[0013] In this way, it is possible to accurately determine whether or not a leakage has occurred in each of the plurality of batteries. [Effects of the Invention]

[0014] According to the present disclosure, it is possible to provide a vehicle equipped with a removable battery that performs appropriate leakage detection. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a diagram showing an example of the configuration of a vehicle according to an embodiment of the present invention; [Figure 2] 1 is a diagram illustrating an example of the configuration of a battery exchange system for exchanging a battery pack. [Figure 3] 10 is a flowchart showing an example of a battery pack replacement method. [Figure 4] 4 is a flowchart showing an example of the leakage determination process of FIG. 3. [Figure 5] FIG. 10 is a diagram showing a first example of the configuration of a vehicle according to a modified example. [Figure 6] 10 is a flowchart showing an example of a leakage determination process in a modified example. [Figure 7] FIG. 10 is a diagram showing a second example of the configuration of a vehicle according to a modified example. [Figure 8] FIG. 10 is a diagram showing a third example of the configuration of a vehicle according to a modified example. [Figure 9] FIG. 10 is a diagram showing a fourth example of the configuration of a vehicle according to a modified example. [Figure 10] FIG. 10 is a diagram showing a fifth example of the configuration of a vehicle according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0017] FIG. 1 is a diagram showing an example of the configuration of a vehicle according to this embodiment. Referring to FIG. 1, vehicle 100 includes a vehicle body 10 and a battery pack 20. Vehicle body 10 is the portion of vehicle 100 other than battery pack 20. Vehicle body 10 includes a vehicle drive device serving as a drive source. The vehicle drive device includes an MG (Motor Generator) 11a and an inverter 11b. The vehicle drive device is configured to run vehicle 100 using power output from battery pack 20. Battery pack 20 is configured to be connectable to inverter 11b. Vehicle 100 is, for example, an electric vehicle without an internal combustion engine. However, the present invention is not limited to this, and vehicle 100 may be a plug-in hybrid vehicle with an internal combustion engine, or another type of electric vehicle.

[0018] The vehicle body 10 includes circuits CR11 and CR12. The battery pack 20 includes circuits CR21 and CR22. The circuit CR12 includes an auxiliary battery 17. The circuit CR21 includes a battery 21. The battery 21 is a secondary battery such as a lithium-ion battery, a nickel-metal hydride battery, or a sodium-ion battery. The secondary battery may be a liquid secondary battery or an all-solid-state secondary battery. A plurality of secondary batteries may form a battery pack. The auxiliary battery 17 corresponds to a low-voltage power supply that outputs power at a voltage lower than that of the battery 21. A DC / DC converter 16 is provided between the circuit CR11 and the circuit CR12.

[0019] The circuit CR11 in the vehicle body 10 includes an MG 11a, an inverter 11b, a DC charging relay 14a, a DC inlet 14b, an AC charger 15a, and an AC inlet 15b. The circuit CR21 in the battery pack 20 is provided with a BMS (Battery Management System) 22a and a leakage detector 22b.

[0020] The vehicle body 10 further includes a terminal T11 to which the battery pack 20 can be attached / detached, and an SMR (System Main Relay) 13 arranged between the terminal T11 and the vehicle drive device (inverter 11b). A circuit CR11 (high-voltage power supply line) is connected to the terminal T11 via the SMR 13. The battery pack 20 includes a terminal T21 to which the vehicle body 10 can be attached / detached, and an SMR23 arranged between the terminal T21 and the circuit CR21. The circuit CR21 (high-voltage power supply line) is connected to the terminal T21 via the SMR23.

[0021] Terminal T21 of battery pack 20 is connected to terminal T11 of vehicle body 10. SMR 23 of battery pack 20 is disposed between terminal T21 of battery pack 20 and battery 21. SMR 23 makes it possible to easily and appropriately switch between connection and disconnection between the target device (inverter 11b) and battery 21.

[0022] The vehicle body 10 further includes a terminal T12 to which the battery pack 20 can be attached and detached. A circuit CR12 (low-voltage power supply line) within the vehicle body 10 is connected to the terminal T12. A communication line CL1 (dashed line in FIG. 1) within the vehicle body 10 is also connected to the terminal T12. The battery pack 20 further includes a terminal T22. In the battery pack 20, the circuit CR22 (low-voltage power supply line) and the communication line CL2 (dashed line in FIG. 1) are connected to the terminal T22.

[0023] The auxiliary battery 17 supplies power to drive auxiliary devices mounted on the vehicle 100. The auxiliary battery 17 outputs DC power to a circuit CR12 (low-voltage power supply line). The circuit CR12 further includes ECUs 18a, 18b, and 18c in addition to the auxiliary battery 17. The circuit CR22 further includes ECUs 28a and 28b. The auxiliary battery 17 supplies power to each of the ECUs 18a to 18c, 28a, and 28b connected to the low-voltage power supply line, for example. "ECU" stands for Electronic Control Unit.

[0024] The ECU 18a corresponds to a control device (EV-ECU) that manages various controls related to the vehicle 100. The ECU 18b corresponds to a control device (Plg-ECU) that detects the respective states of the DC inlet 14b and the AC inlet 15b. The ECU 18c corresponds to a control device (Bat-C-ECU) that controls the DC charging relay 14a and the AC charger 15a. The ECU 28a corresponds to a control device (Bat-ECU) that monitors the state of the battery 21 and controls the SMR 23. The ECU 28b corresponds to a control device (earth leakage ECU) that monitors the leakage state of the circuit CR21. For example, the ECU 28b detects a current between the ground and an electric circuit including the circuit CR21, calculates a resistance value of an insulation resistor using the detected current, and determines the calculated resistance value as a leakage state.

[0025] Each ECU includes a processor and a storage device. The storage device is configured to be able to save stored information. The storage device stores programs as well as various information used by the programs. In this embodiment, various controls are performed by the processor executing the programs stored in the storage device. However, these processes may also be performed by hardware (electronic circuits) alone, without using software.

[0026] In vehicle 100, the ECUs are connected to each other so as to be able to communicate with each other via an in-vehicle network (for example, a Controller Area Network (CAN)). ECU 18a acquires information from the other ECUs, controls inverter 11b, DC / DC converter 16, and SMRs 13 and 23, and transmits control commands to ECU 18c and ECU 28a.

[0027] The BMS 22a detects the state (current, voltage, temperature, etc.) of the battery 21 and outputs the detection result to the ECU 28a. The leakage detector 22b detects the leakage state (e.g., insulation resistance) of the circuit CR21 and outputs the detection result to the ECU 28b. The ECU 18a acquires information (state information) indicating the battery state and leakage state from the ECUs 28a and 28b.

[0028] The DC / DC converter 16 transforms DC power between the circuits CR11 and CR12. Specifically, the DC / DC converter 16 steps down the DC power from the battery 21 and outputs it to the auxiliary battery 17 and other accessories connected to the circuit CR12. The capacity of the battery 21 is larger than that of the auxiliary battery 17.

[0029] Terminals T21 and T22 of battery pack 20 are connected to terminals T11 and T12, whereby battery pack 20 is mounted on vehicle body 10 to form vehicle 100. In vehicle 100, communication line CL1 of vehicle body 10 and communication line CL2 of battery pack 20 are connected. These communication lines form an in-vehicle network (e.g., CAN) of vehicle 100.

[0030] The MG 11a functions as a driving motor. The inverter 11b functions as a PCU (Power Control Unit) for the MG 11a. The inverter 11b drives the MG 11a using power supplied from the battery 21 of the battery pack 20. The MG 11a converts the power into torque to rotate the drive wheels of the vehicle 100. Furthermore, the MG 11a performs regenerative power generation, for example, when the vehicle 100 decelerates, to charge the battery 21.

[0031] Each of the DC inlet 14b and the AC inlet 15b has a terminal for detecting connection / disconnection of a charging cable (plug), and outputs a signal indicating whether the charging cable is connected to the ECU 18b. The ECU 18a acquires information indicating the inlet state from the ECU 18b, and sends a control command to the ECU 18c. The AC charger 15a performs AC / DC conversion. The ECUs 18a to 18c work together to perform plug-in charging of the battery 21.

[0032] The vehicle body 10 further includes an HMI (Human Machine Interface) 19a and a communication device 19b. The HMI 19a and the communication device 19b also receive power from the auxiliary battery 17. The HMI 19a includes an input device and a display device installed in the vehicle cabin. The HMI 19a may include a touch panel display. The input device outputs a signal corresponding to an input from a user to the ECU 18a. The communication device 19b is configured to be capable of wireless communication with a server 380 (FIG. 2) described later. The vehicle body 10 is also equipped with various sensors (not shown) (representatively referred to as an on-board sensor 19c). The ECU 18a is configured to acquire the detection results of these sensors directly or via another ECU.

[0033] In this embodiment, the HMI 19a includes a start switch. By operating the start switch, the user of the vehicle 100 can start or stop the control system (including each ECU) of the vehicle 100, or put the vehicle 100 into a Ready-ON state or a Ready-OFF state.

[0034] The Ready-ON state is a state in which the voltage of the battery 21 of the battery pack 20 connected to the vehicle body 10 is applied to the circuit CR11 of the vehicle body 10. In the Ready-ON state, the SMR 13 is closed, the SMR 23 of the battery pack 20 is also closed, and power is supplied to the vehicle drive device (MG 11a and inverter 11b) from the battery 21 corresponding to the closed SMR 23. The Ready-OFF state is a state in which the voltage of the battery 21 is not applied to the circuit CR11. In the Ready-OFF state, the SMR 13 is open, and power is not supplied from the battery 21 of the battery pack 20 to the vehicle drive device.

[0035] The battery pack 20 installed in the vehicle 100 can be replaced with another battery pack. Fig. 2 is a diagram showing an example of the configuration of a battery exchange system that exchanges battery packs. The battery exchange system 300 shown in Fig. 2 is implemented in, for example, a battery exchange station.

[0036] Referring to FIG. 2, the battery exchange system 300 is configured to remove a battery pack mounted on the vehicle 100 from the vehicle body 10 and attach another battery pack to the vehicle body 10.

[0037] Hereinafter, the battery pack collected from the vehicle 100 will be referred to as "battery pack B1," and the battery pack attached to the vehicle 100 in place of the battery pack B1 will be referred to as "battery pack B2." Each of the battery packs B1 and B2 has the configuration of the battery pack shown in FIG. 1. After being attached to the vehicle body 10, the battery pack B2 functions as the battery pack 20 (FIG. 1) in the vehicle 100.

[0038] Specifically, the battery exchange system 300 includes a first storage device 310, a second storage device 320, a collection device 330, a filling device 340, an exchange device 350, a server 380, and a display device 390. The first storage device 310 stores a plurality of battery packs to be supplied to vehicles. The first storage device 310 includes a pack storage unit (e.g., a storage facility) as well as a charger and a supply device. The second storage device 320 stores a plurality of battery packs collected from a plurality of vehicles. The second storage device 320 includes a pack storage unit (e.g., a storage facility) as well as an inspection device and a sorting device. The server 380 includes a processor, a storage device, and a communication device, and functions as a control device. The storage device stores information (e.g., specification information) about each battery pack present in the battery exchange system 300, distinguishing them by battery pack identification information (pack ID). The display device 390 displays information according to instructions from the server 380.

[0039] A battery replacement method will be described below with reference to Figures 1 to 4. Figure 3 is a flowchart showing an example of a battery pack replacement method. Figure 4 is a flowchart showing an example of the leakage determination process of Figure 3. For example, after the vehicle 100 is parked in a predetermined area in the battery replacement station, the ECU 18a starts the process flow of S10 to S14 shown in Figure 3. The ECU 18a may start the process flow in response to a request from a terminal of the user of the vehicle 100 (user terminal) or a request from an input device in the vehicle 100. The ECU 18a and the server 380 are configured to be capable of wireless communication.

[0040] In step (hereinafter, step will be abbreviated as S) 11, the ECU 18a transmits a signal requesting battery pack replacement (hereinafter, referred to as "replacement request signal") to the server 380. The replacement request signal includes identification information (vehicle ID) of the vehicle 100 and specification information of each battery pack (battery pack B1) installed in the vehicle 100. The replacement request signal may include specification information of the vehicle body 10 instead of or in addition to the specification information of the battery pack B1.

[0041] In S12, the ECU 18a determines whether or not replacement of the battery pack 20 has been performed. The determination in S12 is repeated until replacement of the battery pack 20 is completed (NO in S12).

[0042] When the server 380 receives the exchange request signal, it starts the process flow of S31 to S33 in FIG.

[0043] In S31, the server 380 selects a battery pack that matches the specifications of the vehicle 100 (the specifications of the battery pack B1 or the vehicle body 10) indicated by the replacement request signal from among the battery packs (inventory) held by the first storage device 310. If it is determined that there is no battery pack in stock that matches the specifications of the vehicle 100, the server 380 may display a message explaining the situation on the display device 390 and stop the battery replacement process. If a battery pack is selected in S31, the process proceeds to S32.

[0044] In S32, the server 380 controls the exchange device 350 to remove the battery pack B1 from the vehicle body 10. This separates the battery pack B1 from the vehicle body 10. The process then proceeds to S33.

[0045] In S33, the server 380 controls the charger of the first storage device 310 so that the battery pack B2 selected in S31 is charged. However, the charging timing can be changed as appropriate. A charged battery pack may be loaded into the first storage device 310. When charging is completed, the server 380 controls the supply device of the first storage device 310 so that the battery pack B2 is transported (supplied) from the first storage device 310 to the exchange device 350. Next, the server 380 controls the exchange device 350 so that the battery pack B2 is attached to the vehicle body 10. At this time, the SMR 23 of the attached battery pack B2 is in the open state. Thereafter, the server 380 transmits a signal (hereinafter referred to as the "exchange completion signal") to the ECU 18a notifying that the battery pack attachment is complete.

[0046] FIG. 2 shows an example in which the removal and installation of the battery pack are performed in different positions. The vehicle position may be adjusted before the removal of the battery pack, before the installation of the battery pack, or both. A transport device (e.g., a conveyor-type transport device) or a transport robot (not shown) may move the vehicle. However, the removal and installation of the battery pack may also be performed in the same position. The battery pack replacement (removal and installation) may be performed while the vehicle is stationary. The transport method for each of the collection device 330, the supply device, and the filling device 340 is also arbitrary. These transport methods may be conveyor-type or may use a transport robot. Note that the user may manually replace the battery pack (power storage device) without communication between the battery exchange system (station) and the vehicle.

[0047] For example, when battery pack B2 is attached to vehicle body 10, terminals T21 and T22 of battery pack B2 are connected to terminals T11 and T12 of vehicle body 10, respectively. This places vehicle body 10 and battery pack B2 in the connection state shown in Fig. 1. Attaching battery pack B2 to vehicle body 10 connects low-voltage power supply lines (circuits CR12 and CR22) and communication lines (communication lines CL1 and CL2) between vehicle body 10 and battery pack B2. Then, in battery pack B2, the processing flow of S21 to S24 shown in Fig. 3 is started.

[0048] In S21, the ECU 28a is started up by power supplied from the power source (auxiliary battery 17) within the vehicle body 10. Thereafter, the process proceeds to S22.

[0049] In S22, the ECU 28a transmits information indicating the state of the battery pack (hereinafter referred to as "state information") to the ECU 18a. The state information includes, for example, information about the current voltage of the battery 21 detected by the BMS 22a. Note that the state information may also include information about the leakage detection result (leakage state) detected by the leakage detector 22b and the leakage ECU 28b. The voltage of the battery 21 may vary depending on the SOC (State Of Charge) of the battery 21. The SOC is, for example, the ratio of the current amount of charge to the amount of charge in a fully charged state, expressed as 0 to 100%. Thereafter, the process proceeds to S23.

[0050] In S23, the ECU 28a determines whether or not an SMR-on command has been received from the vehicle body 10. The ECU 28a waits in S23 for an SMR-on command from the vehicle body 10 while keeping the SMR 23 open. When the ECU 28a receives the SMR-on command (YES in S23), the process proceeds to S24.

[0051] In S24, the ECU 28a switches the SMR 23 from the open state (disconnected state) to the closed state (connected state).

[0052] On the other hand, when the battery pack B2 is attached to the vehicle body 10, the ECU 18a receives an exchange completion signal (S33) from the server 380. If the determination in S12 is YES, the process proceeds to S13.

[0053] In S13, the ECU 18a determines whether or not the above-mentioned state information has been received from the ECU 28a of the battery pack B2. If the ECU 18a receives the above-mentioned state information from the battery pack (YES in S13), the process proceeds to S14.

[0054] In step S14, the ECU 18a executes a leakage determination process, which will be described below with reference to the flowchart of FIG.

[0055] In S100, the ECU 18a acquires the resistance value of the insulation resistor. The ECU 18a may acquire the resistance value of the insulation resistor from, for example, status information received from the battery pack 20, or may acquire the resistance value of the insulation resistor from the ECU 28b. If multiple battery packs are installed, the ECU 18a may acquire the resistance value of the insulation resistor corresponding to each battery pack from each battery pack. Then, the process proceeds to S102.

[0056] In S102, the ECU 18a determines whether the resistance value of the insulation resistance obtained in S100 is greater than a threshold value α. The threshold value α is a predetermined value for determining whether or not there is a leakage current, and is adapted through experiments, etc. If multiple battery packs are installed, the ECU 18a determines whether the resistance values ​​of the insulation resistance of each battery pack are all greater than the threshold value α. If it is determined that the resistance value of the insulation resistance is greater than the threshold value α (YES in S102), the process proceeds to S104.

[0057] In S104, ECU 18a determines whether the number of battery packs installed in vehicle 100 is two or more. ECU 18a determines whether the number of battery packs installed in vehicle 100 is two or more, for example, by using the number of pack IDs received from the battery packs or information about the number of installed battery packs received from server 380. Thereafter, the process proceeds to S110. Note that if it is determined in S102 that the resistance value of the insulation resistance is equal to or less than threshold value α (NO in S102), the process proceeds to S106.

[0058] In S106, the ECU 18a determines that a battery pack having an insulation resistance value equal to or less than the threshold value α is leaking electricity. For example, the ECU 18a sets a flag associated with the pack ID of the battery pack having an insulation resistance value equal to or less than the threshold value α to an ON state. Then, the process proceeds to S108.

[0059] In S108, the ECU 18a executes a first fail-safe process. The first fail-safe process may include at least one of a process of controlling the SMR 23 of the battery pack having the pack ID corresponding to the flag in the ON state to the OFF state, a process of prohibiting the SMR 23 of the battery pack from being switched to the ON state, a process of controlling the SMR 13 to the OFF state, and a process of prohibiting the SMR 13 from being switched to the ON state. The process then ends.

[0060] In S110, ECU 18a sets the leakage detection of a predetermined one of the plurality of battery packs (hereinafter referred to as the specific battery pack) to the ON state, and sets the leakage detection of the other battery packs to the OFF state. Specifically, ECU 18a turns on a switch of a circuit for detecting the resistance value of the insulation resistance of one of the battery packs to enable leakage detection, and turns off a switch of a circuit for detecting the resistance value of the insulation resistance of the other battery packs to disable leakage detection. Thereafter, the process proceeds to S112. Furthermore, if it is determined that the number of battery packs is less than two (NO in S104), the process proceeds to S112.

[0061] In S112, the ECU 18a sets each SMR to the ON state. The ECU 18a transmits an SMR ON command to the SMR 13 and the SMR 23 of the battery pack 20 (or the SMR 23 of all the battery packs if multiple battery packs 20 are installed). Then, the process proceeds to S114.

[0062] In S114, the ECU 18a acquires the resistance value of the insulation resistor. If a plurality of battery packs 20 are installed, the resistance value of the insulation resistor is acquired from a specific battery pack. Then, the process proceeds to S116.

[0063] In S116, ECU 18a determines whether the resistance value of the insulation resistance is greater than threshold value α. Threshold value α is as described above, and therefore detailed description thereof will not be repeated. If it is determined that the resistance value of the insulation resistance is greater than threshold value α (YES in S116), the process proceeds to S118.

[0064] In S118, the ECU 18a determines that there is no leakage. The process then ends. For example, the ECU 18a sets flags indicating that there is no leakage on both the vehicle body side and the battery pack side to the ON state. The ECU 18a may permit transition to the Ready-ON state on the condition that the flags indicating that there is no leakage are in the ON state. Note that if it is determined that the resistance value of the insulation resistance is equal to or less than the threshold value α (NO in S116), the process proceeds to S120.

[0065] In S120, the ECU 18a determines that there is a leakage current on the vehicle body 10 side. The ECU 18a sets, for example, a flag to an ON state indicating that there is a leakage current on the vehicle body 10 side. Thereafter, the process proceeds to S122.

[0066] In S122, the ECU 18a executes a second fail-safe process. The second fail-safe process may include a process for controlling the SMR 13 to the OFF state, a process for prohibiting the SMR 13 from being switched to the ON state, a process for controlling the SMR 23 of each battery pack (all battery packs if multiple battery packs are installed) to the OFF state, and a process for prohibiting the SMR 23 of each battery pack from being switched to the ON state. The process then ends.

[0067] As described above, vehicle 100 according to this embodiment can detect the presence or absence of a ground fault and identify the cause of the ground fault using the detection result of whether the resistance value of the insulation resistance is below a threshold value when the battery is connected to the electric circuit of vehicle body 10, and the detection result of whether the resistance value of the insulation resistance is below a threshold value when the battery is disconnected from the electric circuit of vehicle body 10. Specifically, if a ground fault is detected before SMR 23 of battery pack 20 is turned on, it can be identified that the cause of the ground fault is attributable to battery pack 20. Furthermore, if it is determined that there is no ground fault in the battery pack and then the SMR 23 of battery pack 20 is turned on and it is determined that there is a ground fault, it can be identified that the cause of the ground fault is attributable to vehicle body 10. Therefore, a vehicle equipped with a removable battery can be provided that performs appropriate ground fault detection.

[0068] Modifications will be described below.

[0069] In the above-described embodiment, the flowchart in FIG. 4 has been described as including processing assuming a case where multiple battery packs 20 are installed. However, if the vehicle 100 is a vehicle that can install a maximum of one battery pack 20 as shown in FIG. 1, the processing of S104 and the processing of S110 in the flowchart in FIG. 4 may be omitted.

[0070] Furthermore, in the above embodiment, the vehicle 100 is described as being equipped with one battery pack 20, but the vehicle 100 may be equipped with a plurality of battery packs 20. In this case, each of the plurality of battery packs 20 is provided with an SMR 23 that connects and disconnects the battery packs 20 from the electric circuit of the vehicle body 10. The ECU 18a changes the combination of the on and off states of the SMRs 23 in the plurality of battery packs 20 to detect the presence or absence of a leakage current for each battery.

[0071] Fig. 5 is a diagram showing a first example of the configuration of a vehicle 100 according to a modified example. Vehicle 100 shown in Fig. 5 differs from vehicle 100 shown in Fig. 1 in that it includes battery packs 20A and 20B instead of battery pack 20, and a parallel circuit CR13 that connects battery packs 20A and 20B in parallel to SMR 13. Battery packs 20A and 20B have the same configuration as battery pack 20. Therefore, detailed description thereof will not be repeated.

[0072] In this configuration, when the leakage current determination process shown in FIG. 4 is executed, ECU 18a acquires the resistance value of the insulation resistance from each battery pack (S100), and if the resistance value of the insulation resistance of any battery pack is equal to or less than threshold value α (NO in S102), it is determined that there is a leakage current in that battery pack (S106), and the first fail-safe process is executed (S108).

[0073] On the other hand, if the resistance value of the insulation resistance of each battery pack is greater than the threshold value α (YES in S102), the number of battery packs is two or more (YES in S104), so the leakage detection of a specific battery pack (e.g., battery pack 20A) is set to ON, and the leakage detection of another battery pack (battery pack 20B) is set to OFF (S110).

[0074] Thereafter, SMR 13, SMR 23 of battery pack 20A, and SMR 23 of battery pack 20B are turned on (S112), and the resistance value of the insulation resistance is acquired from battery pack 20A (S114). If the acquired resistance value is greater than threshold value α (YES in S116), it is determined that there is no leakage (S118), and if the resistance value is equal to or less than threshold value α, it is determined that there is leakage in the vehicle body (S120), and the second fail-safe process is executed (S122).

[0075] In this way, in a vehicle equipped with multiple battery packs, it is possible to detect the presence or absence of a leakage current in each battery pack when SMR 13 is in the disconnected state. Furthermore, if no leakage current is detected in each battery pack, it is possible to detect the presence or absence of a leakage current in the electric circuit on the vehicle body 10 when SMR 13 is in the conductive state.

[0076] Furthermore, when multiple batteries are installed and SMR13 and SMR23 of each battery pack are set to the on state, leakage detection is performed only in the specific battery pack (battery pack 20A), which reduces interference with the leakage detection devices of other battery packs 20B, allowing leakage to be detected with high accuracy.

[0077] Furthermore, in the above-described embodiment, when multiple batteries are installed, the leakage detection process when a battery pack is replaced is performed to first detect whether or not there is a leakage in each battery pack, and then the leakage detection for battery packs other than the specific battery pack is set to the OFF state. However, leakage detection for other battery packs may also be performed when Ready-OFF is activated.

[0078] The leakage determination process during Ready-OFF will be described below with reference to Fig. 6. Fig. 6 is a flowchart showing an example of leakage determination process in a modified example.

[0079] In S200, the ECU 18a determines whether the state is Ready-OFF. The ECU 18a may determine that the state is Ready-OFF if the ECU 18a has received a start switch operation (OFF operation) during Ready-ON and has not subsequently received a start switch operation (ON operation). If it is determined that the state is Ready-OFF (YES in S200), the process proceeds to S202.

[0080] In S202, the ECU 18a turns off the SMR 13 and the SMRs 23 of the battery packs 20A and 20B, and then the process proceeds to S204.

[0081] In S204, ECU 18a determines whether the number of installed battery packs is two or more. The method for determining the number of battery packs is as described above, and therefore detailed description thereof will not be repeated. If it is determined that the number of installed battery packs is two or more (YES in S204), the process proceeds to S206.

[0082] In S206, the ECU 18a sets the leakage detection of the other battery pack (battery pack 20B) to ON. Then, the process proceeds to S208. If it is determined that the number of installed battery packs is less than two (NO in S204), the process proceeds to S208.

[0083] In S208, the ECU 18a acquires the insulation resistance from the battery pack. If multiple battery packs are installed, the ECU 18a acquires the insulation resistance from each battery pack for which leakage detection is set to ON. Then, the process proceeds to S210.

[0084] In S210, the EUC 18a determines whether the resistance value of the insulation resistance is greater than threshold value α. If it is determined that the resistance value of the insulation resistance is greater than threshold value α (YES in S210), the process proceeds to S212.

[0085] In S212, the ECU 18a determines that there is no leakage, and then the process ends. If it is determined that the resistance value of the insulation resistance is equal to or less than the threshold value α (NO in S210), the process proceeds to S214.

[0086] In S214, the ECU 18a determines that a battery pack having an insulation resistance value equal to or less than the threshold value α has a leakage current. For example, the ECU 18a sets a flag associated with the pack ID of the battery pack having an insulation resistance value equal to or less than the threshold value α to an ON state. Then, the process proceeds to S214.

[0087] In S216, the ECU 18a executes fail-safe processing. The fail-safe processing may include at least one of the following: a process for controlling the SMR 23 of the battery pack having the pack ID corresponding to the flag in the ON state to the OFF state; a process for prohibiting the SMR 23 of the battery pack from being switched to the ON state; a process for controlling the SMR 13 to the OFF state; and a process for prohibiting the SMR 13 from being switched to the ON state. The processing then ends.

[0088] In this way, in a vehicle equipped with a plurality of battery packs, it is possible to detect the presence or absence of leakage in each battery pack when the SMR 13 is in the cutoff state during Ready-OFF.

[0089] Furthermore, the configuration of the vehicle body 10 shown in FIG. 1 or FIG. 5 can be modified as appropriate. For example, the SMR 13 of the vehicle body 10 may be omitted, or the SMR 23 of the battery packs 20, 20A, and 20B may be omitted. Also, at least one of the DC inlet 14b and the AC inlet 15b may be omitted, or may be replaced with a single inlet that is common to AC and DC. These inlets may be configured to enable bidirectional power transmission. The vehicle body may perform external power supply (V2X: Vehicle to Everything) using power output from the attached battery pack.

[0090] Specifically, vehicle 100 may have the configuration shown in Fig. 7. Fig. 7 is a diagram showing a second example of the configuration of vehicle 100 according to a modified example. Vehicle body 10 shown in Fig. 7 differs from vehicle body 10 shown in Fig. 1 in that it does not have SMR 13. Other than that, vehicle body 10 shown in Fig. 7 has the same configuration as vehicle body 10 shown in Fig. 1. Therefore, detailed description thereof will not be repeated.

[0091] Furthermore, the vehicle 100 may have the configuration shown in Fig. 8. Fig. 8 is a diagram showing a third example of the configuration of the vehicle 100 according to a modified example. The vehicle body 10 shown in Fig. 8 differs from the vehicle body 10 shown in Fig. 1 in that it does not have an SMR 23. Other than that, the vehicle body 10 shown in Fig. 8 has the same configuration as the vehicle body 10 shown in Fig. 1. Therefore, detailed description thereof will not be repeated.

[0092] Furthermore, the vehicle 100 may have the configuration shown in Fig. 9. Fig. 9 is a diagram showing a fourth example of the configuration of the vehicle 100 according to a modified example. The vehicle body 10 shown in Fig. 9 differs from the vehicle body 10 shown in Fig. 5 in that it does not have an SMR 13. Other than that, the vehicle body 10 shown in Fig. 9 has the same configuration as the vehicle body 10 shown in Fig. 5. Therefore, detailed description thereof will not be repeated.

[0093] Furthermore, vehicle 100 may have the configuration shown in FIG. 10. FIG. 10 is a diagram showing a fifth example of the configuration of vehicle 100 according to a modified example. Vehicle body 10 shown in FIG. 9 differs from vehicle body 10 shown in FIG. 5 in that it has SMRs 13A and 13B instead of SMRs 13 and 23. SMR 13A is provided on a power supply line connecting terminal T11A and a branch point from a power supply line connecting inverter 11b and terminal T11B. SMR 13B is provided on the power supply line between terminal T11B and the branch point. Other than that, vehicle body 10 shown in FIG. 10 has the same configuration as vehicle body 10 shown in FIG. 5. Therefore, detailed description thereof will not be repeated.

[0094] The above-described modifications may be implemented in whole or in part in appropriate combination.

[0095] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0096] 10 Body, 18a, 28a ECU, 20A, 20B Battery pack, 21 Battery, 23 SMR, 300 Battery exchange system, 350 Exchange device.

Claims

1. The car body and a battery detachable from the vehicle body; a detection device provided in the battery for detecting the presence or absence of a leakage current; A vehicle in which the detection device detects the presence or absence of a leakage current using the detection device when the vehicle is in at least one of a conductive state in which the battery and the vehicle body's electrical circuit are connected, and a disconnected state in which the battery and the electrical circuit are disconnected.

2. 2. The vehicle according to claim 1, wherein the detection device detects the presence or absence of the leakage current in the battery when the detection device is in the disconnected state, and if the leakage current is not detected, detects the presence or absence of the leakage current when the detection device is in the conductive state.

3. the vehicle body is configured to be able to mount a plurality of the batteries, 2. The vehicle according to claim 1, wherein when each of the plurality of batteries and the electric circuit are connected in a conductive state, the presence or absence of the leakage current is detected by one of the plurality of detection devices.

4. the vehicle body is configured to be able to mount a plurality of the batteries, 2. The vehicle according to claim 1, wherein when each of the plurality of batteries is in a disconnected state in which the connection between the battery and the electric circuit is disconnected, the detection device of each of the plurality of batteries detects the presence or absence of the leakage current.

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