Battery electric vehicle

Abstract

The invention relates to a battery-powered vehicle. A battery-powered vehicle is provided with: a motor for travel; an inverter that drives the motor; a first battery; an electrical device operated by the power from the first battery; a detachable and movable second battery; a first connection release device for connecting and releasing the connection between a power line connected to the inverter and the first battery; a second connection release device for connecting and releasing the connection between the power line and the second battery; and a control device for controlling the first connection release device and the second connection release device, the control device controlling the first connection release device and the second connection release device such that the second battery is preferentially connected to the power line than the first battery when the temperature of the second battery is within an allowable temperature range of the second battery when a system start instruction is made.

Description

Technical Field

[0001] The present disclosure relates to a battery electric vehicle. Background Art

[0002] Conventionally, as such a battery electric vehicle, a battery electric vehicle having a motor (motor generator) for traveling, an inverter for driving the motor, an electrical device (electric heating component) that operates with the consumption of electric power, and a battery (main battery) has been proposed (for example, see Japanese Patent Application Laid-Open No. 2015-80284). In this vehicle, when the battery is at a low temperature at system startup, the electrical device is operated to preheat the battery using heat generated by the internal resistance of the battery. Summary of the invention

[0003] However, in the battery-electric vehicle described above, the battery is frequently cold when the system is started. When the battery is frequently cold, the frequency of warming up the battery increases, and the power consumption for warming up the battery increases.

[0004] A main purpose of the battery electric vehicle of the present disclosure is to suppress the power consumption for warming up of the battery.

[0005] The battery electric vehicle disclosed in the present invention adopts the following means to achieve the above-mentioned main purpose. The gist of the battery electric vehicle disclosed in the present invention is that the battery electric vehicle comprises: a motor for running; an inverter that drives the motor; a first battery; an electrical device that operates with the power from the first battery; a removable and portable second battery; a first connection release device that connects and releases the power line connected to the inverter and the first battery; a second connection release device that connects and releases the power line and the second battery; and a control device that controls the first connection release device and the second connection release device, wherein:

[0006] When a system startup instruction is given, when the temperature of the second battery is within the allowable temperature range of the second battery, the control device controls the first connection release device and the second connection release device in such a manner that the second battery is connected to the power line with priority over the first battery.

[0007] In such a battery electric vehicle disclosed in the present invention, it may be that, when the system startup indication is performed and the temperature of the second battery is within the allowable temperature range of the second battery, when a predetermined connection condition is satisfied, the control device controls the first connection release device and the second connection release device in a manner that the power line is disconnected from the first battery and the power line is connected to the second battery, and when the predetermined connection condition is not satisfied, the control device controls the first connection release device and the second connection release device in a manner that the power line is connected to the first battery and the power line is disconnected from the second battery, and operates the electrical equipment to preheat the first battery.

[0008] In this case, the predetermined connection condition may also be that all selected conditions from among the four conditions are met, namely, a first condition that the second battery is normal, a second condition that the power storage ratio of the second battery is within the allowable ratio range of the second battery, a third condition that the temperature of the second battery is higher than the temperature of the first battery, and a fourth condition that the temperature of the first battery is within the non-preheating range in which the first battery can be used without preheating.

[0009] In addition, it may be that, when the system startup instruction is issued and the temperature of the second battery is outside the allowable temperature range, or when the system startup instruction is issued and the temperature of the second battery is within the allowable temperature range and the predetermined connection condition is not satisfied, when the first battery is normal and the power storage ratio of the first battery is within the allowable ratio range of the first battery, the control device controls the first connection release device and the second connection release device in a manner of connecting the power line to the first battery and releasing the connection between the power line and the second battery, and operates the electrical equipment to preheat the first battery, and when the first battery is abnormal or the power storage ratio of the first battery is outside the allowable ratio range of the first battery, the control device prohibits the system startup.

[0010] The battery-electric vehicle of the present disclosure may include a notification device for notifying information, and the control device may control the notification device so as to notify information indicating that the second battery is installed when the system is stopped and the second battery is installed. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0012] Figure 1is a schematic structural diagram of a battery electric vehicle 20 according to an embodiment of the present disclosure;

[0013] Figure 2 is a schematic structural diagram showing the structure of the battery pack 39a;

[0014] Figure 3 is a flowchart showing an example of a startup processing routine;

[0015] Figure 4 is a flowchart showing an example of a stop-time processing routine;

[0016] Figure 5 is a schematic structural diagram of a battery electric vehicle 120 according to another embodiment; and

[0017] Figure 6 This is a flowchart showing an example of a startup processing routine according to another embodiment. DETAILED DESCRIPTION

[0018] Embodiments of the present disclosure will be described with reference to the drawings. Figure 1 1 is a schematic diagram of a battery electric vehicle 20 according to an embodiment of the present disclosure. As shown in the figure, the battery electric vehicle 20 according to the embodiment includes a motor 32, an inverter 34, a first battery 36, an electrical device 37, a second battery 39, and an electronic control unit (hereinafter referred to as "ECU") 50.

[0019] The motor 32 is configured as a three-phase AC motor, and includes a rotor with a permanent magnet embedded in the rotor core and a stator with a three-phase coil wound on the stator core. The rotor of the motor 32 is connected to the drive shaft 26 connected to the drive wheels 22a and 22b via the differential gear 24. The inverter 34 is used to drive the motor 32 and is connected to the power line 38. The inverter 34 includes 6 transistors T11 to T16 as switching elements and 6 diodes D11 to D16 connected in parallel to the 6 transistors T11 to T16, respectively. The transistors T11 to T16 are arranged in pairs of 2 each in such a way that the positive side line and the negative side line relative to the power line 38 are the source side and the drain side. Each connection point of the connection points of the paired transistors of the transistors T11 to T16 is connected to each coil of the three-phase (U phase, V phase, W phase) coil of the motor 32. Therefore, when a voltage is applied to the inverter 34 , the ECU 50 adjusts the ratio of the on-times of the paired transistors T11 to T16 , thereby forming a rotating magnetic field in the three-phase coils and rotating the motor 32 .

[0020] The first battery 36 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery having a rated voltage of several hundred V, and is a specification that cannot be removed by the user and carried indoors. The first battery 36 is connected to the power line 38 via a transistor (first connection release device) 35 as a switching element. Therefore, the transistor 35 connects and releases the first battery 36 and the power line 38. It should be noted that a DCDC converter 38a is installed on the power line 38, and the DCDC converter 38a inputs and outputs the power of the power line 38 to auxiliary machines and auxiliary machine batteries not shown in the figure along with voltage conversion. The electrical device 37 is configured as, for example, a seat heater built into a seat where an occupant sits, and operates using the power from the first battery 36.

[0021] The second battery 39 is configured by connecting two portable battery packs 39a in series, which are detachable and can be carried indoors by a user, and the overall rated voltage is approximately several hundred volts. Figure 239a is a schematic structural diagram showing the structure of the battery pack 39a. The battery pack 39a includes a battery stack 390, a connection release device (second connection release device) 394, a fuse 396, and a battery pack electronic control unit (hereinafter referred to as "battery pack ECU") 398. The battery stack 390 is composed of, for example, stacked battery cells of secondary batteries such as lithium-ion secondary batteries and nickel-hydrogen secondary batteries. The connection release device 394 includes two transistors connected between power terminals 392 and 393 connected to the power line 38 and the output terminal of the battery stack 390. The connection and disconnection of the power line 38 and the battery stack 390 are performed by turning the two transistors on and off. The fuse 396 is connected between the power terminal 392 and the connection release device 394. The battery pack ECU 398 includes a microcomputer, and the microcomputer has a CPU, a ROM, a RAM, a flash memory, an input / output port, and a communication port. The battery pack ECU 398 inputs signals from various sensors via the input port. For example, the battery pack ECU 398 inputs a voltage Vb2 from a voltage sensor 398a, a current Ib2 from a current sensor 398b, a temperature Tb2 from a temperature sensor 398c, an installation signal from an installation detection sensor, and the like. The voltage sensor 398a is installed between the terminals of the battery stack 390. The current sensor 398b is installed at the output terminal of the battery stack 390. The temperature sensor 398c detects the temperature of the battery stack 390. The installation detection sensor detects whether the battery pack 39a is installed. The battery pack ECU 398 outputs various control signals such as a control signal to the transistor of the connection release device 394 via an output port. The battery pack ECU 398 calculates the power storage ratio SOC2a of the battery stack 390a based on the integrated value of the current Ib2 of the battery stack 390 from the current sensor 398b. Here, the power storage ratio SOC2a is the ratio of the power storage capacity allocated to the battery stack 390a to the total capacity of the battery stack 390a. In addition, the battery pack ECU 398 calculates the degradation state SOH2 of the battery stack 390 as the integrated value of the absolute value of the current Ib2 of the battery stack 390 from the current sensor 398b. The battery pack ECU 398 exchanges various data by communicating with the ECU 50 via the terminal 399. Each battery pack 39a configured in this way is configured so that after the system of the battery electric vehicle 20 is stopped, it is unloaded by the user and carried indoors (inside the house) and charged by connecting to a charger indoors. In addition, each battery pack 39a is configured so that when the user uses the battery electric vehicle 20, it is carried from indoors to the battery electric vehicle 20 and installed on the power line 38 by the user.

[0022] ECU50 is equipped with a microcomputer, and the microcomputer has a CPU, ROM, RAM, flash memory, input / output ports, and a communication port. ECU50 inputs signals from various sensors via the input port. For example, ECU50 inputs the rotation position θm from the rotation position sensor (e.g., rotary transformer) 32a that detects the rotation position of the rotor of the motor 32, and the phase currents Iv and Iw from the current sensors 32v and 32w that detect the currents of the V phase and the W phase of the motor 32. ECU50 also inputs the voltage Vb1 from the voltage sensor 36a installed between the terminals of the first battery 36, the current Ib1 from the current sensor 36b installed at the output terminal of the first battery 36, and the temperature Tb1 from the temperature sensor 36v that detects the temperature of the first battery 36. The ECU 50 also inputs a start signal from the start switch 60, a shift position SP from the shift sensor 62, an accelerator opening Acc from the accelerator pedal position sensor 64, a brake pedal position BP from the brake pedal position sensor 66, a vehicle speed V from the vehicle speed sensor 67, an outside temperature Tatm from the temperature sensor 68, and an input signal from the display 70. The shift sensor 62 detects the operation position of the shift lever 61. The accelerator pedal position sensor 64 detects the amount of depression of the accelerator pedal 63. The brake pedal position sensor 66 detects the amount of depression of the brake pedal 65. The temperature sensor 68 detects the outside temperature. The display 70 is configured as a touch panel and is provided in the passenger compartment. The ECU 50 outputs various control signals such as a control signal to the transistors T11 to T16 of the inverter 34, a control signal to the speaker (notification device) 69 provided in the passenger compartment, and a control signal to the display 70 via the output port. The ECU 50 calculates the electrical angle θe and the rotation speed Nm of the motor 32 based on the rotation position θm of the rotor of the motor 32 from the rotation position sensor 32a. The ECU 50 calculates the power storage ratio SOC1 of the first battery 36 based on the integrated value of the current Ib1 from the current sensor 36b. Here, the power storage ratio SOC1 is the ratio of the power storage capacity allocated to the first battery 36 to the total capacity of the first battery 36. In addition, the ECU 50 calculates the degradation state SOH1 of the first battery 36 as the integrated value of the absolute value of the current Ib1 of the first battery 36 from the current sensor 36b. As described above, the ECU 50 exchanges various data with the battery pack ECU 398 through communication.

[0023] In the battery electric vehicle 20 of the embodiment thus configured, the ECU 50 sets the requested torque Td* requested for the fixed drive shaft 26 based on the accelerator opening Acc and the vehicle speed V, and sets the set requested torque Td* as the torque command Tm* of the motor 32, so that the motor 32 is driven by the torque command Tm* to perform switching control of the transistors T11 to T16 of the inverter 34. In the battery electric vehicle 20, when the system is stopped, the connection release device 394 of the transistor 35 and each battery pack 39a of the second battery 39 is disconnected.

[0024] Next, the operation of the battery-powered vehicle 20 according to the embodiment configured in this manner, particularly the operation at the time of system startup and the operation at the time of system shutdown, will be described. Figure 3 2 is a flowchart showing an example of a startup processing routine executed by the ECU 50. The startup processing routine is executed when the startup switch 60 is turned on and a system startup instruction is issued.

[0025] When executing the startup processing routine, the CPU of the ECU 50 executes processing for inputting the voltage Vb1, temperature Tb1, power storage ratio SOC1, degradation state SOH1, voltage Vb2, temperature Tb2, power storage ratio SOC2, and degradation state SOH2 of each battery pack 39a (S100). As the voltage Vb1 and temperature Tb1, the values ​​detected by the voltage sensor 36a and the temperature sensor 36c are input respectively. As the power storage ratio SOC1 and degradation state SOH1, the values ​​calculated by the ECU 50 are input. As for the voltage Vb2 and temperature Tb2 of each battery pack 39a, the values ​​detected by the voltage sensor 398a and the temperature sensor 398c of each battery pack 39a are input respectively through communication via the battery pack ECU 398 of each battery pack 39a. As for the power storage ratio SOC2 and degradation state SOH2 of each battery pack 39a, the values ​​calculated by the battery pack ECU 398 of each battery pack 39a are input respectively through communication.

[0026] Next, based on the input of the display 70, the CPU of the ECU 50 determines whether to select the second battery 39 as the battery used by the user (S110). It is generally believed that the user wants to actively use the second battery 39 when the driving distance is extended. In addition, since the second battery 39 is detachable, it is sometimes used as a power source for other electrical equipment at the destination, such as when used at a camping site, instead of being used as a power source for driving. In such a case, the first battery 36 or the second battery 39 can be selected as the battery used by the user through the input of the display 70.

[0027] When the second battery 39 is selected in S110, the CPU of the ECU 50 determines whether each battery pack 39a constituting the second battery 39 is installed (S120). When each battery pack 39a is installed, the CPU of the ECU 50 determines whether the temperature Tb2 of each battery pack 39a is equal to or higher than the lower limit temperature Tbmin (S130). The lower limit temperature Tbmin is the lower limit value of the allowable temperature range allowed for the use of the second battery 39 (each battery pack 39a).

[0028] When the temperature Tb2 of all battery packs 39a is higher than the lower limit temperature Tbmin in S130, the CPU of the ECU 50 determines that the second battery 39 (each battery pack 39a) is at a temperature suitable for use, and determines whether the second battery 39 is normal (first condition) (S140). Regarding this determination, when two conditions are satisfied: the voltage Vb2 of each battery pack 39a is within the normal voltage range, and the degradation state SOH2 is lower than the value indicating that the battery pack 39a is significantly degraded, the second battery 39 is determined to be normal. When the second battery 39 is normal in S140, the CPU of the ECU 50 determines whether the power storage ratio SOC2 of each battery pack 39a is within the allowable range of more than the lower limit ratio SOC2min and less than the upper limit ratio SOC2max (second condition) (S150). The lower limit ratio SOC2min and the upper limit ratio SOC2max are predetermined values ​​as the lower limit value and the upper limit value of the power storage ratio allowed when the battery pack 39a is used. When the power storage ratio SOC2 is within the allowable range in S150, the CPU of the ECU 50 determines whether the temperature Tb2 of each battery pack 39a is higher than the temperature Tb1 of the first battery 36 (third condition) (S160). When the temperature Tb2 of each battery pack 39a is higher than the temperature Tb1 of the first battery 36 in S160, the CPU of the ECU 50 determines whether it is in the non-preheating range (fourth condition) in which the temperature Tb1 of the first battery 36 is higher than the start temperature Tbst (for example, -12°C, -10°C, -8°C, etc.) (S170). The start temperature Tbst is a temperature that is a lower limit value of the temperature at which the temperature Tb1 of the first battery 36 can be used without preheating the first battery 36. When the temperature Tb1 of the first battery 36 is lower than the start temperature Tbst, the second battery 39 is used at the time of system startup, and when the power storage ratio SOC of the second battery 39 becomes low, even if the first battery 36 is used, it may not be used without preheating. S170 is a determination made in view of such a situation, and is a process for determining whether the first battery 36 can be used without preheating after the second battery 39 is used. When the temperature Tb1 of the first battery 36 is equal to or higher than the startup temperature Tbst in S170, the CPU of the ECU 50 turns off the transistor 35 to disconnect the power line 38 from the first battery 36. Then, the CPU of the ECU 50 turns on the connection disconnection device 394 of each battery pack 39a to connect the power line 38 to the second battery 39 (S180), and ends the startup processing routine. Through such processing, the power line 38 is connected to the second battery 39 at the time of system startup, and the second battery 39 is used after the system is started. In this way, when the temperature Tb2 of all the battery packs 39a is equal to or higher than the lower limit temperature Tbmin, when the conditions of S140 to S170 are met, the second battery 39 is used preferentially over the first battery 36, and the use of the first battery 36 is suppressed. Therefore, the preheating of the first battery 36 can be suppressed.This can reduce power consumption for warming up the battery.

[0029] When the second battery 39 is not selected in S110, when each battery pack 39a is not installed in S120, when the temperature Tb2 of any battery pack 39a is less than the lower limit temperature Tbmin in S130, and when the temperature Tb2 of all battery packs 39a is greater than the lower limit temperature Tbmin in S130, each condition from S140 to S170 may not be satisfied. In this case, the CPU of the ECU 50 determines that it is better to use the first battery 36 than the second battery 39, and determines whether the first battery 36 is normal (S190). This determination is made when two conditions are satisfied: the condition that the voltage Vb1 of the first battery 36 is within the normal voltage range, and the condition that the degradation state SOH1 is less than the value indicating that the first battery 36 is significantly degraded. When the first battery 36 is normal in S190, it is determined whether the power storage ratio SOC1 of the first battery 36 is within the allowable range of more than the lower limit ratio SOC1min and less than the upper limit ratio SOC1max (S200). The lower limit ratio SOC1min and the upper limit ratio SOC1max are predetermined values ​​as the lower limit value and the upper limit value of the power storage ratio allowed when the first battery 36 is used. When the power storage ratio SOC1 is within the allowable range in S200, the CPU of the ECU50 turns on the transistor 35 to connect the power line 38 to the first battery 36. Furthermore, the CPU of the ECU50 disconnects the connection release device 394 of each battery pack 39a to disconnect the power line 38 from the second battery 39, and operates the electrical device 37 to preheat the first battery 36 by using the heat generated by the internal resistance of the first battery 36 (S210). As a result, the CPU of the ECU50 ends the startup processing routine. By such processing, the power line 38 and the first battery 36 are connected at the time of system startup, and the first battery 36 is used after the system startup. In this way, when the temperature Tb2 of any battery pack 39a is lower than the lower limit temperature Tbmin, the first battery 36 can be used when the conditions of S190 to S210 are met. At this time, since the first battery 36 is preheated, the first battery 36 can be put into a good state for use.

[0030] When the first battery 36 is abnormal in S190 and the power storage ratio SOC1 is outside the permissible range in S200, it is determined that the first battery 36 should not be used, the system startup is prohibited (S220), and the startup processing routine is terminated. When the first battery 36 is abnormal and the power storage ratio SOC1 is outside the permissible range, the battery electric vehicle 20 may not be able to travel before reaching the destination after the battery electric vehicle 20 starts traveling using the first battery 36. When the first battery 36 is abnormal and the power storage ratio SOC1 is outside the permissible range, the system startup is prohibited, thereby preventing the battery electric vehicle 20 from being unable to travel after the start of traveling and before reaching the destination.

[0031] Next, the operation of battery-powered vehicle 20 when the system is stopped will be described. Figure 4 2 is a flowchart showing an example of a stop processing routine executed by the ECU 50. The stop processing routine is executed when the start switch 60 is pressed at system startup to issue a system stop instruction.

[0032] When executing the stop processing routine, the CPU of the ECU 50 performs processing of inputting the external temperature Tatm detected by the temperature sensor 68 (S300). Next, it is determined whether the second battery 39, i.e., each battery pack 39a, is installed (S310), and whether the external temperature Tatm is below the predetermined temperature Tlow (S320). The predetermined temperature Tlow is a threshold value of the external temperature at which the second battery 39 deteriorates when the second battery 39 is left installed on the power line 38, and is set to, for example, -20°C, -15°C, -10°C, etc. When each battery pack 39a is not installed, or when each battery pack 39a is installed but the external temperature Tatm exceeds the predetermined temperature Tlow, the stop processing routine is terminated.

[0033] When each battery pack 39a is installed in S310 and the outside temperature Tatm is below the predetermined temperature Tlow in S320, the CPU of the ECU 50 determines that the second battery 39 should not be placed. Then, the CPU of the ECU 50 outputs the meaning that the second battery 39 is installed by sound from the speaker 69 (S330), and ends the stop processing routine. Through such processing, it is possible to notify the user and make the user recognize that the second battery 39 is installed, and prompt the user to remove each battery pack 39a of the second battery 39. As a result, it is possible to prevent forgetting to remove each battery pack 39a, and it is possible to more reliably store the second battery 39 in a place with a high temperature such as indoors. As a result, the temperature of the second battery 39 can be within the allowable temperature range when the system is started. In addition, more preferably, the second battery 39 is connected to the power line 38 with priority over the first battery 36, and the use of the second battery 39 is prioritized over the first battery 36, so that the power consumption for preheating the first battery 36 can be suppressed. It should be noted that, in S330 , it may be determined that the second battery 39 should not be placed, and the fact that the second battery 39 is mounted may be displayed on the display 70 .

[0034] According to the battery electric vehicle 20 of the embodiment described above, when a system start instruction is issued, when the temperature Tb2 of the second battery 39 is within the allowable temperature range of the lower limit temperature Tbmin or more, the transistor 35 and the disconnection device 394 are controlled so that the second battery 39 is connected to the power line 38 with priority over the first battery 36. Therefore, the power consumption for warming up the first battery 36 can be suppressed.

[0035] In addition, when the system startup instruction is issued and the temperature Tb2 of each battery pack 39a is within the allowable temperature range, the predetermined connection conditions including S140 to S170 are sometimes satisfied. In this case, the transistor 35 and the connection release device 394 are controlled in such a manner that the connection between the power line 38 and the first battery 36 is released and the power line 38 is connected to the second battery 39. When the predetermined connection condition is not satisfied, the transistor 35 and the connection release device 394 are controlled in such a manner that the power line 38 is connected to the first battery 36 and the connection between the power line 38 and the second battery 39 is released, and the electric device 37 is operated to preheat the first battery 36. Therefore, more appropriately, the second battery 39 can be connected to the power line 38 with priority over the first battery 36, and the use of the second battery 39 can be prioritized over the first battery 36.

[0036] Furthermore, since the predetermined connection condition is satisfied when all of S140 to S170 are satisfied, it is possible that the second battery 39 is more appropriately connected to the power line 38 than the first battery 36 , and the second battery 39 is used more preferentially than the first battery 36 .

[0037] Furthermore, there is a case where the system start instruction is given and the temperature Tb2 of the second battery 39 is less than the lower limit temperature Tbmin and is outside the allowable temperature range. Alternatively, when the system start instruction is given and the temperature of the second battery 39 is within the allowable temperature range above the lower limit temperature Tbmin and the predetermined connection conditions including S140 to S170 are not satisfied, sometimes the first battery 36 is normal and the power storage ratio SOC of the first battery 36 is within the allowable ratio range of the first battery 36. In these cases, the transistor 35 and the connection release device 394 are controlled in such a manner that the power line 38 is connected to the first battery 36 and the connection between the power line 38 and the second battery 39 is released. In addition, the electrical device 37 is operated to preheat the first battery 36, and when the first battery 36 is abnormal or the power storage ratio SOC1 of the first battery 36 is outside the allowable ratio range of the first battery 36, the system start is prohibited. In this way, it is possible to prevent the battery electric vehicle 20 from being unable to travel before reaching the destination after the start of travel.

[0038] Furthermore, a speaker 69 is provided as a notification means for notifying information. When the system is stopped, if the second battery 39 is installed, the speaker 69 is controlled to notify information indicating that the second battery 39 is installed. Therefore, more preferably, the second battery 39 is connected to the power line 38 with priority over the first battery 36, and the use of the second battery 39 is prioritized over the first battery 36, so that the power consumption for warming up the first battery 36 can be suppressed.

[0039] In the above embodiment, the first battery 36 is of a specification that cannot be removed by the user and carried indoors. Figure 5 As shown in the example of the first battery 136 of the battery electric vehicle 120 of another embodiment, the first battery 136 is replaced by a first battery 136 having a total rated voltage of several hundred V and having a structure similar to the second battery 39, in which two portable battery packs 39a are connected in series and can be loaded and unloaded and carried indoors by a user. In this case, the first battery 136 is not preheated by the electrical device 37. In the battery electric vehicle 120 of another embodiment, when the system startup instruction is issued, the first battery 136 is replaced by the first battery 136. Figure 3 The startup processing routine shown in the example executes Figure 6 The startup processing routine is shown.

[0040] In execution Figure 6During the startup processing routine, the CPU of the ECU 50 executes processing (S400) of inputting the voltage Vb2, temperature Tb2, power storage ratio SOC2, and degradation state SOH2 of each battery pack 39a of the first battery 136 and the second battery 39. The voltage Vb2 and temperature Tb2 of each battery pack 39a are respectively inputted by the battery pack ECU 398 of each battery pack 39a through communication, and the values ​​detected by the voltage sensor 398a and the temperature sensor 398c of each battery pack 39a are respectively inputted. The power storage ratio SOC2 and degradation state SOH2 of each battery pack 39a are respectively inputted by the battery pack ECU 398 of each battery pack 39a through communication.

[0041] Next, the CPU of the ECU 50 determines whether all the battery packs 39a constituting the first battery 136 and the second battery 39 are installed (S410). When all the battery packs 39a are installed, the CPU of the ECU 50 determines whether the temperature Tb2 of all the battery packs 39a is higher than the start-up temperature Tbst (S420). When the temperature Tb2 of all the battery packs 39a is higher than the start-up temperature Tbst in S420, the CPU of the ECU 50 determines whether the first battery 136 is normal (S430). Regarding this determination, when two conditions are met, that the voltage Vb2 of each battery pack 39a of the first battery 136 is within the normal voltage range, and the degradation state SOH2 is lower than the value indicating that the battery pack 39a is significantly degraded, it is determined that the first battery 136 is normal. When the first battery 136 is normal in S430, the CPU of the ECU 50 determines whether the power storage ratio SOC2 of each battery pack 39a of the first battery 136 is within the allowable range of more than the lower limit ratio SOC2min and less than the upper limit ratio SOC2max (S440). When the power storage ratio SOC2 is within the allowable range in S440, the CPU of the ECU 50 determines whether the lowest temperature Tb2low1 among the temperatures Tb2 of each battery pack 39a of the first battery 136 is higher than the lowest temperature Tb2low2 among the temperatures Tb2 of each battery pack 39a of the second battery 39 (S450). When the temperature Tb2low1 is higher than the temperature Tb2low2, the CPU of the ECU 50 determines that the first battery 136 is preferably used in preference to the second battery 39. Then, the CPU of the ECU 50 turns on the connection release device 394 of each battery pack 39a of the first battery 136 to connect the power line 38 to the first battery 36. Furthermore, the CPU of the ECU 50 turns off the disconnection device 394 of each battery pack 39 a of the second battery 39 , disconnects the power line 38 from the second battery 39 ( S460 ), and terminates the startup processing routine.

[0042] When S430 to S450 are not true, Figure 3The same process as S140 of the illustrated startup processing routine is used to determine whether the second battery 39 is normal (S470). When the second battery 39 is normal, the CPU of the ECU 50 determines whether the power storage ratio SOC2 of each battery group 39a of the second battery 39 is within the allowable range of greater than the lower limit ratio SOC2min and less than the upper limit ratio SOC2max (S480). This process is similar to the Figure 3 The same processing as S150 of the illustrated startup processing routine is performed. If the power storage ratio SOC2 is within the allowable range in S480, the power storage ratio SOC2 is controlled by the Figure 3 The same process as S150 of the illustrated startup processing routine is performed, and it is determined that it is better to use the second battery 39 in priority to the first battery 136. Then, the CPU of the ECU 50 disconnects the connection release device 394 of each battery pack 39a of the first battery 136, and disconnects the power line 38 from the first battery 36. Furthermore, the CPU of the ECU 50 disconnects the connection release device 394 of each battery pack 39a of the second battery 39 and connects the power line 38 to the second battery 39 (S490), and ends the startup processing routine.

[0043] When each battery pack 39a is not installed in S410, when the temperature Tb2 of any battery pack 39a is lower than the start temperature Tbst in S420, when the second battery 39 is abnormal in S470, and when the power storage ratio SOC2 is out of the allowable range in S480, the CPU of the ECU 50 determines that the first battery 136 and the second battery 39 should not be used, prohibits system startup (S500), and ends the startup processing routine. By such processing, it is possible to prevent the battery electric vehicle 20 from being unable to travel after starting to travel but before reaching the destination.

[0044] In the above embodiment, S140 to S170 are executed, but some of the four processes may be selected and executed, and the unselected processes may not be executed. Figure 4 The stop processing routine illustrated, but the stop processing routine may not be executed. In the above-mentioned embodiment, the poor conditions of the first battery 36 and the second battery 39 of the present disclosure at low temperatures are dealt with, but the poor conditions at high temperatures can also be dealt with. In this case, for example, S130 can be changed to whether the temperature Tb2 of each battery pack 39a is below the upper limit temperature Tmax of the allowable temperature range, etc., and appropriate changes can be made. In the above-mentioned embodiment, the second battery 39 is set to a structure in which two battery packs 39a are connected in series. However, the second battery 39 can also be set to a structure in which more than three battery packs 39a are connected in series, and the second battery 39 can also be set to a structure with one battery pack 39a. The second battery 39 can also be set to a structure in which multiple battery packs 39a are connected in parallel.

[0045] It should be noted that the correspondence between the main elements of the embodiment and the main elements of the invention recorded in the "Contents of the Invention" column is an example of a way to specifically explain the embodiment for implementing the invention recorded in the "Contents of the Invention" column, and therefore does not limit the elements of the invention recorded in the "Contents of the Invention" column. That is, the interpretation of the invention recorded in the "Contents of the Invention" column should be based on the description in that column, and the embodiment is only a specific example of the invention recorded in the "Contents of the Invention" column.

[0046] As mentioned above, although the embodiment for implementing this disclosure was described, this disclosure is not limited to such embodiment at all, and it is needless to say that this disclosure can be implemented in various forms within the scope not departing from the gist of this disclosure.

Claims

1. A battery-electric vehicle, comprising: a motor for traveling; an inverter for driving the motor; a first battery; an electrical device operated by power from the first battery; a removable and movable second battery; a first connection release device for connecting and releasing a power line connected to the inverter and the first battery; a second connection release device for connecting and releasing the power line and the second battery; and a control device for controlling the first connection release device and the second connection release device, wherein: When a system startup instruction is issued, when the temperature of the second battery is within the allowable temperature range of the second battery, the control device controls the first connection release device and the second connection release device in such a manner that the second battery is connected to the power line with priority over the first battery.

2. The battery electric vehicle according to claim 1, wherein: When the system startup indication is performed and the temperature of the second battery is within the allowable temperature range of the second battery, when a predetermined connection condition is satisfied, the control device controls the first connection release device and the second connection release device in a manner that the power line is disconnected from the first battery and the power line is connected to the second battery. When the predetermined connection condition is not satisfied, the control device controls the first connection release device and the second connection release device in a manner that the power line is connected to the first battery and the power line is disconnected from the second battery, and operates the electrical equipment to preheat the first battery.

3. The battery electric vehicle according to claim 2, wherein: The predetermined connection conditions are selected from four conditions: a first condition that the second battery is normal, a second condition that the power storage ratio of the second battery is within the allowable ratio range of the second battery, a third condition that the temperature of the second battery is higher than the temperature of the first battery, and a fourth condition that the temperature of the first battery is within the non-preheating range in which the first battery can be used without preheating. All of these conditions are met.

4. The battery electric vehicle according to claim 2, wherein: When the system startup instruction is issued and the temperature of the second battery is outside the allowable temperature range, or when the system startup instruction is issued and the temperature of the second battery is within the allowable temperature range and the predetermined connection condition is not satisfied, when the first battery is normal and the power storage ratio of the first battery is within the allowable ratio range of the first battery, the control device controls the first connection release device and the second connection release device in a manner of connecting the power line to the first battery and disconnecting the power line from the second battery, and operates the electrical equipment to preheat the first battery. When the first battery is abnormal or the power storage ratio of the first battery is outside the allowable ratio range of the first battery, the control device prohibits the system startup.

5. The battery electric vehicle according to claim 1, wherein: Also provided is a notification device for notifying information, The control device controls the notification device so as to notify information indicating that the second battery is installed when the second battery is installed when the system is stopped.

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