Vehicle

Abstract

To inhibit malfunctions from being caused in a vehicle by a plurality of batteries mounted on the vehicle.SOLUTION: A vehicle includes: an object device; and a first power storage device and a second power storage device that can be connected in parallel to the object device. The first power storage device includes a first battery. The second power storage device includes a second battery. When a voltage difference between a voltage of the first battery and a voltage of the second battery is greater than a reference value (No in S102), at least one of the first battery and the second battery is not connected to the object device.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a vehicle including a plurality of power storage devices.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2022-174873 (Patent Document 1) discloses a vehicle including a plurality of replaceable batteries.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the vehicle described in Patent Document 1, batteries are provided individually for four motor control units. That is, one battery is provided for each one target device (for example, a motor control unit) mounted on the vehicle. However, it is also conceivable to connect a plurality of batteries in parallel to one target device for the purpose of supplying a large amount of power to the target device. However, when a plurality of batteries are connected to one target device, there is a possibility that a problem may occur in the vehicle depending on the states of those batteries. For example, the target device may be damaged.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to suppress the occurrence of problems in the vehicle due to a plurality of batteries mounted on the vehicle.

Means for Solving the Problems

[0006] A vehicle according to an aspect of the present disclosure includes a target device, a first power storage device, and a second power storage device that can be connected in parallel to the target device. The first power storage device includes a first battery. The second power storage device includes a second battery. When the voltage difference between the voltage of the first battery and the voltage of the second battery is greater than a reference value, at least one of the first battery and the second battery is not connected to the target device.

Advantages of the Invention

[0007] According to the present disclosure, it becomes possible to suppress the occurrence of problems in the vehicle due to a plurality of batteries mounted on the vehicle.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0009] Embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and the description thereof will not be repeated.

[0010] FIG. 1 is a diagram showing the configuration of a vehicle according to this embodiment. Referring to FIG. 1, the vehicle 100 includes a vehicle body 10, a battery pack 20A (first power storage device), and a battery pack 20B (second power storage device). The vehicle body 10 is a part of the vehicle 100 other than the battery packs 20A and 20B. The vehicle body 10 includes a vehicle drive device. The vehicle drive device includes an MG (Motor Generator) 11a and an inverter 11b, and corresponds to an example of the "target device" according to the present disclosure. The vehicle drive device is configured to drive the vehicle 100 using the electric power output from each of the battery packs 20A and 20B. The battery packs 20A and 20B are configured to be connectable in parallel to the inverter 11b. The vehicle 100 is, for example, a battery electric vehicle (BEV) that does not include an internal combustion engine. However, the present invention is not limited to this, and the vehicle 100 may be a plug-in hybrid vehicle (PHEV) including an internal combustion engine, or may be another electric vehicle (xEV). In this embodiment, since the battery packs 20A and 20B have the same configuration, hereinafter, they are referred to as "battery pack 20" when they are not distinguished from each other.

[0011] The vehicle body 10 includes circuits CR11 and CR12. The battery pack 20 includes circuits CR21 and CR22. The circuit CR12 includes an accessory battery 17. The circuit CR21 includes a battery 21. The battery 21 is a secondary battery such as, for example, a lithium-ion battery, a nickel-metal hydride battery, or a sodium-ion battery. The type of 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 accessory battery 17 corresponds to a low-voltage power supply that outputs electric 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.

[0012] 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. Further, a leakage detector 12 is provided in the circuit CR11. In the circuit CR21 in the battery pack 20, a BMS (Battery Management System) 22a and a leakage detector 22b are provided.

[0013] The vehicle body 10 further includes a terminal T11A to which the battery pack 20A is detachable, a terminal T11B to which the battery pack 20B is detachable, a parallel circuit CR13 that connects the terminal T11A and the terminal T11B in parallel, and an SMR13 disposed between the parallel circuit CR13 and the vehicle drive device (inverter 11b). The circuit CR11 (high-voltage power line) is connected to each of the terminals T11A and T11B via the SMR13 and the parallel circuit CR13. Each of the battery packs 20A and 20B includes a terminal T21 to which the vehicle body 10 is detachable, and an SMR23 disposed between the terminal T21 and the circuit CR21. The circuit CR21 (high-voltage power line) is connected to the terminal T21 via the SMR23. "SMR" means a System Main Relay.

[0014] The terminal T21 of the battery pack 20A is connected to the terminal T11A (first terminal) of the vehicle body 10. The SMR23 (first relay) of the battery pack 20A is disposed between the terminal T21 (third terminal) and the battery 21 (first battery) in the battery pack 20A. The terminal T21 of the battery pack 20B is connected to the terminal T11B (second terminal) of the vehicle body 10. The SMR23 (second relay) of the battery pack 20B is disposed between the terminal T21 (fourth terminal) and the battery 21 (second battery) in the battery pack 20B. Each relay enables easy and appropriate switching of the connection / disconnection between the target device (inverter 11b) and each of the first battery and the second battery.

[0015] The vehicle body 10 further includes a terminal T12A to which the battery pack 20A is detachable, and a terminal T12B to which the battery pack 20B is detachable. A circuit CR12 (low-voltage power line) inside the vehicle body 10 is connected to each of the terminals T12A and T12B via a parallel circuit CR13. The parallel circuit CR13 connects the terminal T12A and the terminal T12B in parallel. A communication line CL1 (broken line in FIG. 1) inside the vehicle body 10 is also connected to each of the terminals T12A and T12B. Each of the battery packs 20A and 20B further includes a terminal T22. In each of the battery packs 20A and 20B, a circuit CR22 (low-voltage power line) and a communication line CL2 (broken line in FIG. 1) are connected to the terminal T22.

[0016] The auxiliary battery 17 supplies electric power for driving auxiliary devices mounted on the vehicle 100. The auxiliary battery 17 outputs DC power to a circuit CR12 (low-voltage power line). The circuit CR12 further includes ECUs 18a, 18b, 18c, and 18d 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 18d, 28a, and 28b connected to the low-voltage power line, for example. "ECU" means an Electronic Control Unit.

[0017] The ECU 18a corresponds to a control device (EV-ECU) that overall controls various controls related to the vehicle 100. The ECU 18b corresponds to a control device (Plg-ECU) that detects the state of each 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 18d corresponds to a control device (first leakage ECU) that monitors the leakage state of the circuit CR11. 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 (second leakage ECU) that monitors the leakage state of the circuit CR21.

[0018] Each ECU includes a processor and a storage device. The storage device is configured to be able to store the stored information. In addition to the program, various information used in the program is stored in the storage device. In this embodiment, various controls are executed by the processor executing the program stored in the storage device. However, these processes may be executed only by hardware (electronic circuit) without using software.

[0019] In vehicle 100, each ECU is communicably connected to each other via an in-vehicle network (for example, CAN (Controller Area Network)). ECU18a acquires information from other ECUs, controls the inverter 11b, the DC / DC converter 16, and the SMRs 13, 23, and transmits control commands to ECU18c and ECU28a.

[0020] The leakage detector 12 detects the leakage state (for example, insulation resistance) of the circuit CR11 and outputs the detection result to the ECU18d. The BMS 22a detects the state (current, voltage, temperature, etc.) of the battery 21 and outputs the detection result to the ECU28a. The leakage detector 22b detects the leakage state of the circuit CR21 and outputs the detection result to the ECU28b. The ECU18a acquires information indicating the battery state and the leakage state from the ECUs 18d, 28a, and 28b.

[0021] The DC / DC converter 16 steps down DC power between the circuit CR11 and the circuit CR12. Specifically, the DC / DC converter 16 steps down the DC power from the battery 21 and outputs it to the auxiliary battery 17. The capacity of the battery 21 is larger than the capacity of the auxiliary battery 17.

[0022] The terminals T21 and T22 of the battery pack 20A are connected to the terminals T11A and T12A, and the terminals T21 and T22 of the battery pack 20B are connected to the terminals T11B and T12B, whereby the battery packs 20A and 20B are mounted on the vehicle body 10, and the vehicle 100 is completed. In the vehicle 100, the communication line CL1 of the vehicle body 10, the communication line CL2 of the battery pack 20A, and the communication line CL2 of the battery pack 20B are connected. These communication lines constitute the in-vehicle network (e.g., CAN) of the vehicle 100.

[0023] MG11a functions as a motor for driving. The inverter 11b functions as a PCU (Power Control Unit) for MG11a. The inverter 11b drives MG11a using the electric power supplied from the battery 21 of each battery pack. MG11a converts the electric power into torque and rotates the drive wheels of the vehicle 100. Also, MG11a performs regenerative power generation, for example, when the vehicle 100 decelerates, and charges the battery 21.

[0024] Each of the DC inlet 14b and the AC inlet 15b has a terminal for detecting the connection / disconnection of a charging cable (plug), and outputs a signal indicating whether or not the charging cable is connected to the ECU18b. The ECU18a acquires information indicating the inlet state from the ECU18b and transmits a control command to the ECU18c. The AC charger 15a performs AC / DC conversion. Plug-in charging of the battery 21 is executed by the cooperation of the ECUs 18a to 18c.

[0025] The vehicle body 10 further includes an HMI (Human Machine Interface) 19a and a communication device 19b. Note that the HMI 19a and the communication device 19b also receive power supply from the auxiliary battery 17. The HMI 19a includes an input device and a display device provided in the vehicle interior. The HMI 19a may include a touch panel display. The input device outputs a signal corresponding to an input from the 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. In addition, various sensors (in-vehicle sensors 19c) (not shown) are also mounted on the vehicle body 10. The ECU 18a is configured to acquire the detection results of these sensors directly or via other ECUs.

[0026] In this embodiment, the HMI 19a includes a start switch. Generally, the start switch is referred to as a "power switch" or an "ignition switch", etc. The user of the vehicle 100 can start or stop the control system (including each ECU) of the vehicle 100 or set the vehicle 100 to the Ready-ON state or the Ready-OFF state by operating the start switch. Each operation may be a remote operation (for example, a request by wireless communication).

[0027] The Ready-ON state is a state in which the voltage of at least one of the batteries 21 of the battery packs 20A and 20B 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 in the closed state, and at least one of the SMRs 23 of the battery packs 20A and 20B is also in the closed state, and power is supplied from the battery 21 corresponding to the closed SMR 23 to the vehicle drive device (MG11a and inverter 11b). 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 in the open state, and no power is supplied from any of the batteries 21 of the battery packs 20A and 20B to the vehicle drive device.

[0028] The battery packs 20A and 20B mounted on the vehicle 100 can be replaced with other battery packs. FIG. 2 is a diagram showing an example of the configuration of a battery replacement system for performing battery pack replacement. The battery replacement system 300 shown in FIG. 2 is implemented, for example, in a battery replacement station.

[0029] Referring to FIG. 2, the battery replacement system 300 is configured to remove the battery packs mounted on the vehicle 100 from the vehicle body 10 and attach other battery packs to the vehicle body 10. Hereinafter, an example in which two battery packs (battery packs 20A and 20B) are simultaneously removed from the vehicle 100 and two replacement battery packs are simultaneously attached to the vehicle 100 will be described. However, it is not limited to this, and the battery packs 20A and 20B may be replaced one by one in order.

[0030] Hereinafter, the two battery packs recovered from the vehicle 100 will be referred to as "battery packs B11 and B12". Also, the two battery packs attached to the vehicle 100 in place of the battery packs B11 and B12 will be referred to as "battery packs B21 and B22". Each of the battery packs B11, B12, B21, and B22 has the configuration of the battery pack shown in FIG. 1. The battery packs B21 and B22 attached to the vehicle body 10 function as the battery packs 20A and 20B (FIG. 1) in the vehicle 100.

[0031] Specifically, the battery swapping system 300 includes a first storage device 310, a second storage device 320, a recovery device 330, a charging device 340, a swapping 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. In addition to a pack storage section (e.g., a storage), the first storage device 310 includes a charger and a supply device. The second storage device 320 stores a plurality of battery packs recovered from a plurality of vehicles. In addition to a pack storage section (e.g., a storage), the second storage device 320 includes 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) regarding each battery pack existing within the battery swapping system 300, differentiated by the identification information (pack ID) of the battery pack. The display device 390 displays information according to an instruction from the server 380.

[0032] Hereinafter, a battery swapping method will be described with reference to FIGS. 1 to 3. FIG. 3 is a flowchart showing the processing related to the battery swapping method according to this embodiment. For example, after the vehicle 100 parks in a predetermined area within the battery swapping station, the ECU 18a starts the processing flow of S11 to S14 shown in FIG. 3. The ECU 18a may start the processing flow in response to a request from a user terminal (e.g., HMI 19a) of the vehicle 100. The ECU 18a and the server 380 are configured to be able to communicate wirelessly. In the flowchart, "S" means step.

[0033] Referring to FIGS. 1, 2, and 3, in S11, the ECU 18a transmits a signal (hereinafter referred to as an "exchange request signal") requesting the replacement of the battery pack to the server 380. The exchange request signal includes the identification information (vehicle ID) of the vehicle 100 and the specification information of each battery pack (battery packs B11, B12) mounted on the vehicle 100. The exchange request signal may include the specification information of the vehicle body 10 instead of or in addition to the specification information of the battery packs B11, B12. In the subsequent S12, the ECU 18a determines whether the battery pack has been replaced. While the replacement of the battery pack is not completed (NO in S12), the determination in S12 is repeatedly executed.

[0034] When the server 380 receives the above replacement request signal, it starts the processing flow of S31 to S33. In S31, the server 380 selects two battery packs that match the specifications of the vehicle 100 (the specifications of the battery packs B11, B12 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 that matches the specifications of the vehicle 100 in the inventory, the server 380 may display a message for situation explanation on the display device 390 and abort the battery replacement process. If a battery pack is selected in S31, then in the subsequent S32, the server 380 controls the replacement device 350 so that the battery packs B11, B12 are removed from the vehicle body 10. As a result, the vehicle body 10 and the battery packs B11, B12 are separated.

[0035] Although not shown in the flowchart, a reuse process is executed for the removed battery packs B11, B12. Specifically, the recovery device 330 conveys (recovers) the battery packs B11, B12 from the replacement device 350 to the second storage device 320. Then, the plurality of battery packs stored in the second storage device 320 are inspected in order by an inspection device, and a sorting device sorts those battery packs according to the inspection results for each use. Each battery pack is reused for the corresponding use (in-vehicle use, stationary use, etc.). However, battery packs that cannot be reused are discarded. The battery packs (for in-vehicle use) reused in the battery replacement system 300 are conveyed to the first storage device 310 by the filling device 340. The conveyed battery packs are filled in the first storage device 310.

[0036] In S33, the server 380 controls the charger of the first storage device 310 so that each battery 21 of the battery packs B21 and B22 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 the charging is completed, the server 380 controls the supply device of the first storage device 310 so that the battery packs B21 and B22 are transported (supplied) from the first storage device 310 to the replacement device 350. Subsequently, the server 380 controls the replacement device 350 so that the battery packs B21 and B22 are attached to the vehicle body 10. At this time, each SMR23 of the battery packs B21 and B22 is in an open state. After that, the server 380 transmits a signal (hereinafter referred to as "replacement completion signal") notifying the completion of the attachment of the battery pack to the ECU18a.

[0037] FIG. 2 shows an example in which the removal of the battery pack and the attachment of the battery pack are performed at different positions. The vehicle position may be adjusted before the removal of the battery pack, before the attachment of the battery pack, or both. A transport device (for example, a conveyor type transport device) or a transport robot (not shown) may move the vehicle. However, the removal of the battery pack and the attachment of the battery pack may be performed at the same position. The battery pack may be replaced (removed and attached) with the vehicle stationary. The transport method of each of the recovery device 330, the supply device, and the filling device 340 is also arbitrary. These transport methods may be a conveyor method or a method using a transport robot. Note that the user may manually replace the battery pack (power storage device) without the battery exchange system (station) and the vehicle communicating with each other.

[0038] When the battery packs B21 and B22 are attached to the vehicle body 10, the terminals T21 and T22 of the battery pack B21 are connected to the terminals T11A and T12A of the vehicle body 10 respectively, and the terminals T21 and T22 of the battery pack B22 are connected to the terminals T11B and T12B of the vehicle body 10 respectively. As a result, the vehicle body 10 and the battery packs B21, B22 are in the connection state shown in FIG. 1. By attaching the battery packs B21 and B22 to the vehicle body 10, a low-voltage power line (circuits CR12, CR22) and a communication line (communication lines CL1, CL2) are connected between the vehicle body 10 and each of the battery packs B21, B22. Then, in each of the battery packs B21 and B22, the processing flows of S21 to S24 shown in FIG. 3 are started.

[0039] In S21, the ECU28a is activated by the power supplied from the power source (auxiliary battery 17) in the vehicle body 10. Subsequently, in S22, the activated ECU28a transmits information indicating the state of the battery pack (hereinafter referred to as "state information") to the ECU18a. The state information indicates, for example, the current voltage of the battery 21 detected by the BMS22a. The voltage of the battery 21 can vary according to the SOC (State Of Charge) of the battery 21. The SOC represents, for example, the ratio of the current stored power to the stored power in the fully charged state, expressed as 0 to 100%.

[0040] Subsequently, in S23, the ECU28a determines whether it has received an SMR on command (S103, S107 in FIG. 4 described later) from the vehicle body 10. The ECU28a waits for the SMR on command from the vehicle body 10 in S23 while keeping the SMR23 in the open state. When the ECU28a receives the SMR on command (YES in S23), in S24, the ECU28a switches the SMR23 from the open state (cut-off state) to the closed state (connected state).

[0041] On the one hand, when the battery packs B21 and B22 are attached to the vehicle body 10, the ECU 18a receives a replacement completion signal (S33) from the server 380. As a result, it is determined as YES in S12, and the process proceeds to S13. In S13, the ECU 18a determines whether it has received the above state information from each of the ECUs 28a of the battery packs B21 and B22. When the ECU 18a receives the above state information from each battery pack (YES in S13), the ECU 18a executes the processing flow shown in FIG. 4 in S14.

[0042] FIG. 4 is a flowchart showing the processing executed by the ECU 18a in the vehicle body 10 after the battery packs B21 and B22 are attached to the vehicle body 10. Referring to FIG. 4, in S101, the ECU 18a determines whether the voltage of each battery 21 of the battery packs B21 and B22 is within a predetermined range (hereinafter referred to as the "allowable range") based on the state information (S22 in FIG. 3) acquired from the ECU 28a. The allowable range indicates the conditions under which each of the battery packs B21 and B22 can operate normally in the vehicle 100, and more specifically corresponds to the appropriate voltage range of the battery 21. The allowable range may be set according to the vehicle drive system (for example, the circuit CR11 and the control system) of the vehicle 100.

[0043] When the voltage of each battery 21 in the battery packs B21 and B22 is within the allowable range (YES in S101), the ECU18a determines in S102 whether the difference (voltage difference) between the voltage of the battery 21 (first battery) in the battery pack B21 and the voltage of the battery 21 (second battery) in the battery pack B22 is smaller than a predetermined reference value. When the voltage difference is smaller than the reference value (YES in S102), the ECU18a transmits in S103 a signal (SMR on command) instructing the closing drive of the SMR23 to each of the battery packs B21 and B22. As a result, the SMR23 of each battery pack becomes closed (S24 in FIG. 3). Subsequently, the ECU18a switches the SMR13 from the open state to the closed state in S104. Thereby, the vehicle 100 enters the Ready-ON state, the batteries 21 of each of the battery packs B21 and B22 are connected to the inverter 11b, and the voltage of each battery is applied to the inverter 11b. In this way, when the battery packs B21 and B22 are attached to the vehicle body 10, the ECU18a confirms that the voltage difference between the two batteries 21 attached to the vehicle body 10 is sufficiently small, and then connects all of the SMR13 of the vehicle body 10, the SMR23 of the battery pack B21, and the SMR23 of the battery pack B22, and applies the voltages of both of the two batteries 21 connected in parallel to the vehicle drive device to the vehicle drive device. When the process of S104 is executed, S14 in FIG. 3, and thus the processing flow regarding battery replacement ends. Thereafter, the ECU18a may start the running of the vehicle 100 in a state where a plurality of batteries (the batteries 21 of each of the battery packs B21 and B22) are connected in parallel to the vehicle drive device. During the running of the vehicle 100 or during plug-in charging, when the voltage difference between the plurality of batteries connected to the vehicle drive device becomes larger than the reference value, the ECU18a may turn off the SMR23 of either the battery pack B21 or B22 and disconnect one of those batteries from the vehicle drive device. Further, the ECU18a may execute control to equalize the power storage amounts of those batteries during the running of the vehicle 100 or during plug-in charging so that the voltage difference between those batteries does not become larger than the reference value.

[0044] If the voltage of battery 21 is not within the allowable range for at least one of battery packs B21 and B22 (NO in S101), ECU18a issues a notification prompting the replacement of the battery pack to the user terminal (e.g., HMI19a) of vehicle 100 in S108. After that, in S109, ECU18a determines whether a replacement request has been received from the user. When the user terminal receives the notification in S108, it displays, for example, screen Sc1. Screen Sc1 displays messages M11, M12 and operation units P11, P12. Message M11 prompts the user of vehicle 100 to replace the battery pack. Message M12 shows an explanation regarding operation units P11, P12. If operation unit P11 is operated, it is determined as YES in S109, and after ECU18a transmits a replacement request signal requesting the replacement of the battery pack whose voltage of battery 21 was not within the allowable range to server 380 in S110, the process returns to S12 in FIG. 3. Due to the replacement request signal, the processing flow of S31 to S33 shown in FIG. 3 starts again. However, in this processing flow, only the battery pack whose voltage of battery 21 was not within the allowable range is replaced. On the other hand, if operation unit P12 is operated, it is determined as NO in S109, S14 in FIG. 3 ends, and the processing flow regarding battery replacement ends.

[0045] If the voltage difference between the two batteries attached to vehicle body 10 is equal to or greater than the reference value (NO in S102), ECU18a issues a notification prompting the user of vehicle 100 to select either driving or replacement in S105. After that, in S106, ECU18a determines which of driving or replacement the user has selected. When the user terminal receives the notification in S105, it displays, for example, screen Sc2. Screen Sc2 displays messages M21, M22 and operation units P21, P22. Message M21 notifies the user of vehicle 100 that all battery packs cannot be used simultaneously. Message M22 prompts the user to operate either operation unit P21 corresponding to "driving" or operation unit P22 corresponding to "replacement".

[0046] When the operation unit P22 is operated, it is determined in S106 that "replacement" has been selected, and the process proceeds to S110. In S110, after the ECU18a transmits a replacement request signal to the server 380, the process returns to S12 in FIG. 3. The ECU18a may request the server 380 to replace both the battery packs B21 and B22 by the replacement request signal. Alternatively, the ECU18a may request the server 380 to replace only the battery pack with the lower priority among the battery packs B21 and B22 by the replacement request signal. The priority may be determined in the same manner as in S107 described later.

[0047] When the operation unit P21 is operated, it is determined in S106 that "travel" has been selected, and in S107, the ECU18a selects the battery pack with the higher priority among the battery packs B21 and B22, and transmits an SMR on command to the ECU28a of the selected battery pack. Specifically, the ECU18a determines the priority based on at least one of the voltage, the stored power, and the maximum output of the battery 21 of each battery pack. The ECU18a may determine that the higher the voltage of the battery 21, the higher the stored power of the battery 21, and the larger the maximum output (W) of the battery 21, the higher the priority. The ECU18a may select the battery pack with the higher voltage of the battery 21 in S107. Alternatively, the ECU18a may select the battery pack with the larger maximum output of the battery 21 in S107. When the maximum outputs of the battery 21 are the same for the battery packs B21 and B22, the ECU18a may select the battery pack with the larger stored power of the battery 21. When the output (for example, output current or output power) of the battery 21 in each battery pack is limited to be equal to or lower than the output upper limit value by control, the ECU18a may regard the output upper limit value as the maximum output.

[0048] By the process of S107, the SMR23 of the selected battery pack (the battery pack with a high priority) becomes in the closed state (S24 in FIG. 3). Subsequently, the ECU18a switches the SMR13 from the open state to the closed state in S104. As a result, the vehicle 100 becomes in the Ready-ON state, and the battery 21 of the battery pack selected in S107 is connected to the inverter 11b. According to the battery pack with a high priority, it becomes easier to supply the power required for the inverter 11b.

[0049] As described above, the battery replacement method according to this embodiment includes each process shown in FIGS. 3 and 4. The vehicle 100 according to this embodiment includes a battery pack 20A (battery pack B21) and a battery pack 20B (battery pack B22) that can be connected in parallel to a vehicle drive device (target device). And when the voltage difference between the voltage of the battery 21 of the battery pack 20A and the voltage of the battery 21 of the battery pack 20B is larger than the reference value, at least one of the battery 21 of the battery pack 20A and the battery 21 of the battery pack 20B is not connected to the vehicle drive device (inverter 11b). Specifically, when the voltage difference is smaller than the reference value (YES in S102 of FIG. 4), the ECU18a (control device) of the vehicle body 10 connects all of the SMR13 of the vehicle body 10, the SMR23 of the battery pack 20A, and the SMR23 of the battery pack 20B in the connected state, and when the voltage difference is larger than the reference value (NO in S102 of FIG. 4), the SMR23 of at least one of the battery packs 20A and 20B is put in the cut-off state.

[0050] For example, when two batteries with a large voltage difference are connected in parallel to one target device, an overcurrent may flow through the target device. Such an overcurrent may damage the target device. In this regard, according to the above configuration, when the voltage difference between the two batteries 21 included in the battery packs 20A and 20B is large, at least one of those two batteries 21 is not connected to the target device. Thereby, the flow of an overcurrent through the target device is suppressed.

[0051] The vehicle body may be configured to be connectable to three or more battery packs (power storage devices). FIG. 5 is a diagram showing a modification of the configuration shown in FIG. 1. Referring to FIG. 5, the vehicle body 10A includes detachable terminals T11A, T12A for the first battery pack, detachable terminals T11B, T12B for the second battery pack, and detachable terminals T11C, T12C for the third battery pack. The vehicle body 10A is configured to be connectable to at least the first to third battery packs. Also, the vehicle body 10A includes a parallel circuit CR13A instead of the parallel circuit CR13 (FIG. 1). The parallel circuit CR13A connects the terminals T11A, T11B, T11C (high-voltage power line) in parallel and connects the terminals T12A, T12B, T12C (low-voltage power line) in parallel.

[0052] The ECU 18a (control device) of the vehicle body 10A can also replace three or more battery packs (power storage devices) by the method shown in FIGS. 3 and 4. However, in this modification, in S102 of FIG. 4, when selecting a combination of two battery packs (two batteries) from three or more battery packs attached to the vehicle body 10A, it is determined whether the voltage difference of all combinations is smaller than the reference value. Also, the ECU 18a according to the modification executes, for example, the processing flow shown in FIG. 6 in S107 of FIG. 4. FIG. 6 is a flowchart showing a modification of the method of selecting a battery (battery pack) to be connected to the target device.

[0053] Referring to FIG. 6, in S201, the ECU 18a determines whether there is a combination of batteries with a voltage difference smaller than a predetermined reference value among three or more battery packs attached to the vehicle body 10A. Specifically, the ECU 18a acquires the voltage differences between two batteries for all combinations of three or more battery packs attached to the vehicle body 10A, and determines whether the voltage difference for each combination of batteries is smaller than the reference value. If there is even one combination of batteries with a voltage difference smaller than the reference value (YES in S201), the ECU 18a, in S202, selects a plurality of battery packs corresponding to the combination of batteries with a voltage difference smaller than the reference value, and transmits an SMR on command to each of the selected battery packs. As a result, the SMR 23 of each of the selected battery packs becomes in the closed state (S24 in FIG. 3). Thereafter, the process proceeds to S104 in FIG. 4.

[0054] For example, when a first battery pack including a first battery, a second battery pack including a second battery, and a third battery pack including a third battery are attached to the vehicle body 10A, the ECU 18a acquires the voltage difference between the first battery and the second battery (the first combination), the voltage difference between the first battery and the third battery (the second combination), and the voltage difference between the second battery and the third battery (the third combination). Each of the first to third battery packs has the same configuration as the battery pack 20 described above, and each of the first to third batteries corresponds to the battery 21 in the corresponding battery pack. If only the voltage difference of one of the first to third combinations is smaller than the reference value, an SMR on command is transmitted to each of the two battery packs corresponding to that combination. If the voltage difference of each of two of the first to third combinations is smaller than the reference value, an SMR on command is transmitted to each of the two battery packs corresponding to one combination selected from the two combinations. At this time, a combination including a battery pack with a higher priority (see S107 in FIG. 4) may be selected. If the voltage difference of each of the first to third combinations is smaller than the reference value, it is determined YES in S102 in FIG. 4, and in the subsequent S103, an SMR on command is transmitted to each of the first to third battery packs.

[0055] On the other hand, if there is no combination of batteries with a voltage difference smaller than the reference value (NO in S201), the process proceeds to S203. For example, when the first to third battery packs are attached to the vehicle body 10A, if the voltage difference of each of the first to third combinations is equal to or greater than the reference value, the process proceeds to S203. In S203, the ECU18a selects one battery pack with the highest priority (see S107 in FIG. 4) from among three or more battery packs attached to the vehicle body 10A. Then, the ECU18a sends an SMR on command to the ECU28a of the selected battery pack. As a result, the SMR23 of the selected battery pack is closed (S24 in FIG. 3). After that, the process proceeds to S104 in FIG. 4.

[0056] When three or more battery packs are attached to the vehicle body 10A, the ECU18a (control device) according to the above modification example acquires the voltage difference between two batteries for all combinations of the three or more battery packs, and connects the combination of batteries with a voltage difference smaller than the reference value to the target device (inverter 11b) (S202), and does not connect the combination of batteries with a voltage difference larger than the reference value to the target device (inverter 11b) (S202, S203). According to such a configuration, by not connecting the combination of batteries with a voltage difference larger than the reference value to the target device, it is possible to suppress the flow of an overcurrent to the target device. In addition, by connecting the combination of batteries with a voltage difference smaller than the reference value to the target device, for example, it becomes easier to supply the power required for the vehicle to travel to the target device.

[0057] The processing flows shown in FIGS. 3, 4, and 6 can be changed as appropriate. For example, in the processing flow shown in FIG. 4, S101 and subsequent steps may be omitted. Further, the processing (however, at least one of the two batteries with a voltage difference larger than the reference value is not connected to the target device) when the voltage difference between two batteries attached to the vehicle body is larger than the reference value (S105 to S107, S110) may be changed to another process.

[0058] The configuration of the vehicle body shown in FIG. 1 can be changed as appropriate. For example, SMR13 may be omitted. Also, at least one of the DC inlet 14b and the AC inlet 15b may be omitted, or they may be changed to a single inlet common to AC / DC. These inlets may be configured to enable bidirectional power transmission. The vehicle body may perform external power supply (V2X: Vehicle to Everything) using the power output from the attached battery pack. The target device is not limited to the vehicle drive device and may include a discharger and / or a discharge relay for external power supply.

[0059] The configuration of the battery pack shown in FIG. 1 can also be changed as appropriate. For example, the battery pack 20 may further include a battery temperature adjustment device driven by the power from the auxiliary battery 17. The battery pack 20 may have a power source for the ECU28a. It is not essential that the plurality of battery packs (power storage devices) provided in the vehicle have the same configuration, and they may have different configurations. The power storage device is not limited to the battery pack and may have a packless structure.

[0060] The user terminal is not limited to the in-vehicle HMI and may be a mobile terminal carried by the vehicle user. Examples of the mobile terminal include a smartphone, a laptop, a portable game machine, a wearable device, and an electronic key. The vehicle is not limited to a passenger car and may be a bus, a truck, or a work vehicle (for example, a tractor, a combine, or a forklift). The vehicle may be configured to be capable of unmanned driving by autonomous driving or remote driving.

[0061] The above various modifications may be implemented in any combination.

[0062] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present invention is shown by the claims rather than the description of the above embodiments, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0063] 100 vehicle, 10, 10A vehicle body, 13 SMR, 18a ECU, 20A, 20B battery pack, 21 battery, 23 SMR, 28a ECU, 300 battery swapping system, CR13, CR13A parallel circuit.

Claims

1. A vehicle comprising a target device, a first power storage device, and a second power storage device that can be connected in parallel to the target device, wherein the first power storage device includes a first battery, the second power storage device includes a second battery, when the voltage difference between the voltage of the first battery and the voltage of the second battery is greater than a reference value, at least one of the first battery and the second battery is not connected to the target device.

2. The vehicle further includes a vehicle body connectable to the first power storage device and the second power storage device, the vehicle body includes the target device and a control device, the control device obtains the voltage difference when the first power storage device and the second power storage device are attached to the vehicle body, and when the voltage difference is less than the reference value, connects both the first battery and the second battery to the target device. The vehicle according to claim 1.

3. When the voltage difference is greater than the reference value, the control device connects one battery selected based on at least one of voltage, power storage amount, and maximum output among the first battery and the second battery to the target device. The vehicle according to claim 2.

4. The vehicle body further includes a first terminal to which the first power storage device is detachable, a second terminal to which the second power storage device is detachable, and a parallel circuit that connects the first terminal and the second terminal in parallel, the first power storage device further includes a third terminal connectable to the first terminal and a first relay disposed between the third terminal and the first battery, the second power storage device further includes a fourth terminal connectable to the second terminal and a second relay disposed between the fourth terminal and the second battery, When the voltage difference is less than the reference value, the control device puts both the first relay and the second relay in a connected state, and when the voltage difference is greater than the reference value, puts at least one of the first relay and the second relay in a cutoff state. The vehicle according to claim 2 or 3.

5. The vehicle further includes a vehicle body connectable to three or more power storage devices including the first power storage device and the second power storage device, the vehicle body includes the target device and a control device, each of the three or more power storage devices includes a battery, When the three or more power storage devices are attached to the vehicle body, the control device obtains the voltage difference between two of the batteries for all combinations of the three or more power storage devices, connects the combination of the batteries with the voltage difference smaller than the reference value to the target device, and does not connect the combination of the batteries with the voltage difference larger than the reference value to the target device. The vehicle according to claim 1.

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