Electric vehicles

Abstract

To suppress power consumption due to warming up a battery.SOLUTION: An electric vehicle includes: a motor for travelling; an inverter driving the motor; a first battery; electrical equipment actuated by electric power from the first battery; a detachable portable-type second battery; a first connection release device performing connection between a power line connected to the invertor, and the first battery, and performing release of the connection; a second connection release device performing connection between the power line and the second battery and performing release of the connection; and a control device controlling the first connection / release device and the second connection / release device. The control device controls the first and the second connection / release devices so that the second battery is connected to the power line preferentially to the first battery if the temperature of the second battery is within the acceptable temperature range of the second battery when a system start instruction is made.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to electric vehicles.

Background Art

[0002] Conventionally, as this type of electric vehicle, there has been proposed one including a traveling motor (motor generator), an inverter that drives the motor, an electric device (electric heating means) that operates with power consumption, and a battery (main battery) (see, for example, Patent Document 1). In this vehicle, when the battery is cold at the time of system startup, the battery is warmed up by heat generated by the internal resistance of the battery by operating the electric device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described electric vehicle, at the time of system startup, the battery is often cold. When the frequency with which the battery is cold increases, the frequency of warming up the battery increases, and the power consumption for warming up the battery increases.

[0005] The main object of the electric vehicle of the present disclosure is to suppress the power consumption for warming up the battery.

Means for Solving the Problems

[0006] To achieve the above-mentioned main objective, the electric vehicle of this disclosure employs the following means. The electric vehicle of this disclosure comprises a motor for driving, an inverter for driving the motor, a first battery, electrical equipment powered by electricity from the first battery, a detachable portable second battery, a first disconnection device for connecting and disconnecting a power line connected to the inverter from the first battery, a second disconnection device for connecting and disconnecting the power line from the second battery, and a control device for controlling the first disconnection device and the second disconnection device, wherein, when a system start command is given, the control device controls the first and second disconnection devices so that, when the temperature of the second battery is within the allowable temperature range of the second battery, the second battery takes priority over the first battery in connecting to the power line.

[0007] In the electric vehicle of this disclosure, the control device may, when the system start command is given and the temperature of the second battery is within the allowable temperature range of the second battery, control the first and second disconnection devices to disconnect the power line from the first battery and connect the power line from the second battery when predetermined connection conditions are met, and when the predetermined connection conditions are not met, control the first and second disconnection devices to connect the power line from the first battery and disconnect the power line from the second battery, and also operate the electrical equipment to warm up the first battery. In this case, the predetermined connection conditions may be all of the selected conditions from among four conditions: a first condition that the second battery is normal, a second condition that the charge 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 warm-up-less range where the first battery can be used without warming up. Furthermore, the control device may, when the system start command is issued and the temperature of the second battery is outside the allowable temperature range, or when the system start command is issued and the temperature of the second battery is within the allowable temperature range and the predetermined connection conditions are not met, control the first and second disconnection devices so that the power line and the first battery are connected and the power line and the second battery are disconnected, and operate the electrical equipment to warm up the first battery, while prohibiting the system start command when the first battery is not normal or the charge level of the first battery is outside the allowable temperature range.

[0008] An electric vehicle according to the present disclosure, comprising a notification device for notifying information, wherein the control device may control the notification device to notify information that the second battery is installed when the system is stopped and the second battery is installed. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram of the electric vehicle 20 according to the embodiment of this disclosure. [Figure 2] A schematic diagram showing the general configuration of battery pack 39a. [Figure 3] A flowchart showing an example of a startup processing routine. [Figure 4] A flowchart showing an example of a stop-down processing routine. [Figure 5] A schematic diagram of the electric vehicle 120 in another embodiment. [Figure 6] A flowchart showing an example of a startup processing routine in another embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram of an electric vehicle 20 according to an embodiment of the present disclosure. As shown in the figure, the electric vehicle 20 of the embodiment includes a motor 32, an inverter 34, a first battery 36, electrical equipment 37, a second battery 39, and an electronic control unit (hereinafter referred to as "ECU") 50.

[0011] The motor 32 is configured as a three-phase AC motor and comprises a rotor with permanent magnets embedded in a rotor core and a stator with three-phase coils wound around a stator core. The rotor of the motor 32 is connected to a drive shaft 26 which is connected to drive wheels 22a and 22b via a differential gear 24. The inverter 34 is used to drive the motor 32 and is connected to the power line 38. The inverter 34 comprises six switching elements, transistors T11 to T16, and six diodes D11 to D16, each connected in parallel to the six transistors T11 to T16. The transistors T11 to T16 are arranged in pairs, with two on each side, acting as the source and sink sides for the positive and negative lines of the power line 38. Each connection point of a pair of transistors T11 to T16 is connected to each of the three-phase (U-phase, V-phase, W-phase) coils of the motor 32. Therefore, when 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 coil and driving the motor 32 to rotate.

[0012] The first battery 36 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery with a rated voltage of several hundred volts, and is designed so that it cannot be removed by the user and transported indoors. The first battery 36 is connected to the power line 38 via a transistor (first disconnection device) 35 as a switching element. Therefore, the transistor 35 connects and disconnects the first battery 36 and the power line 38. A DC-DC converter 38a is attached to the power line 38, which inputs and outputs power from the power line 38 to auxiliary equipment and auxiliary batteries (not shown) with voltage conversion. The electrical equipment 37 is configured as, for example, a seat heater built into the seat where the occupant sits, and operates on power from the first battery 36.

[0013] The second battery 39 consists of two portable battery packs 39a connected in series, which are detachable and can be transported indoors by the user, and is configured to have a total rated voltage of several hundred volts. Figure 2 is a schematic diagram showing the configuration of the battery pack 39a. The battery pack 39a includes a cell stack 390, a disconnection device (second disconnection device) 394, a fuse 396, and an electronic control unit for the battery pack (hereinafter referred to as "battery pack ECU") 398. The cell stack 390 is composed of stacked battery cells of a secondary battery, such as a lithium-ion secondary battery or a nickel-metal hydride secondary battery. The disconnection device 394 includes two transistors connected between power terminals 392 and 393 connected to the power line 38 and the output terminal of the cell stack 390, and connects and disconnects the power line 38 and the cell stack 390 by turning the two transistors on and off. The fuse 396 is connected between the power terminal 392 and the disconnection device 394. The battery pack ECU398 is equipped with a microcomputer, which includes a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The battery pack ECU398 receives signals from various sensors via its input ports. For example, it receives voltage Vb2 from voltage sensor 398a attached between the terminals of the cell stack 390, current Ib2 from current sensor 398b attached to the output terminals of the cell stack 390, temperature Tb2 from temperature sensor 398c that detects the temperature of the cell stack 390, and an installation signal from an installation detection sensor that detects whether or not the battery pack 39a is installed. The battery pack ECU398 outputs various control signals, such as control signals to the transistors of the disconnection device 394, via its output ports. The battery pack ECU398 calculates the charge storage ratio SOC2a of the cell stack 390a based on the integrated value of the current Ib2 of the cell stack 390 from current sensor 398b. Here, the energy storage ratio SOC2a is the ratio of the capacity allocated to the energy storage in the cell stack 390a to the total capacity of the cell stack 390a.Furthermore, the battery pack ECU 398 calculates the degradation state SOH2 of the cell stack 390 as the integrated absolute value of the current Ib2 of the cell stack 390 from the current sensor 398b. The battery pack ECU 398 exchanges various data with the ECU 50 via communication through terminal 399. Each of the battery packs 39a configured in this way is removed by the user after the electric vehicle 20 system is shut down, transported indoors (inside the house), and charged by being connected to an indoor charger. When the user uses the electric vehicle 20, the battery pack is transported from indoors to the electric vehicle 20 and installed on the power line 38 by the user.

[0014] The ECU50 is equipped with a microcomputer, which includes a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The ECU50 receives signals from various sensors via its input ports. For example, the ECU50 receives the rotational position θm from a rotational position sensor (e.g., resolver) 32a that detects the rotational position of the rotor of the motor 32, and the phase currents Iv and Iw from current sensors 32v and 32w that detect the V-phase and W-phase currents of the motor 32. It also receives the voltage Vb1 from a voltage sensor 36a attached between the terminals of the first battery 36, the current Ib1 from a current sensor 36b attached to the output terminal of the first battery 36, and the temperature Tb1 from a temperature sensor 36v that detects the temperature of the first battery 36. The ECU 50 receives input signals from the start switch 60, the shift position SP from the shift sensor 62 which detects the operating position of the shift lever 61, the accelerator opening Acc from the accelerator pedal position sensor 64 which detects the amount the accelerator pedal 63 is pressed, the brake pedal position BP from the brake pedal position sensor 66 which detects the amount the brake pedal 65 is pressed, the vehicle speed V from the vehicle speed sensor 67, the outside temperature Tatm from the temperature sensor 68 which detects the outside temperature, and input signals from the display 70 which is configured as a touch panel and installed in the passenger compartment. The ECU 50 outputs various control signals via output ports, such as control signals to transistors T11 to T16 of the inverter 34, control signals to the speaker (notification device) 69 installed in the passenger compartment, and control signals to the display 70. The ECU 50 calculates the electrical angle θe and rotational speed Nm of the motor 32 based on the rotational position θm of the rotor of the motor 32 from the rotational position sensor 32a. The ECU 50 calculates the charge level SOC1 of the first battery 36 based on the integrated value of the current Ib1 from the current sensor 36b. Here, the charge level SOC1 is the ratio of the capacity stored in the first battery 36 to the total capacity of the first battery 36. The ECU 50 also calculates the degradation state SOH1 of the first battery 36 as the integrated value of the absolute values ​​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 via communication.

[0015] In the electric vehicle 20 of this configured embodiment, the ECU 50 sets the required torque Td* required for the drive shaft 26 based on the accelerator opening Acc and vehicle speed V, sets the set required torque Td* as the torque command Tm* for the motor 32, and controls the switching of transistors T11 to T16 of the inverter 34 so that the motor 32 is driven by the torque command Tm*. In the electric vehicle 20, when the system is stopped, the disconnection devices 394 for transistor 35 and each battery pack 39a of the second battery 39 are turned off.

[0016] Next, the operation of the electric vehicle 20 of the embodiment configured in this way, in particular, the operation when the system starts up and the operation when the system stops up, will be described. Figure 3 is a flowchart of an example of a startup processing routine executed by the ECU 50. The startup processing routine is executed when the start switch 60 is turned on and a system start command is given.

[0017] When the startup processing routine is executed, the CPU of ECU50 performs the process of inputting voltage Vb1, temperature Tb1, charge level SOC1, degradation state SOH1, and the voltage Vb2, temperature Tb2, charge level SOC2, and degradation state SOH2 of each battery pack 39a (S100). The voltage Vb1 and temperature Tb1 are input values ​​detected by the voltage sensor 36a and temperature sensor 36c, respectively. The charge level SOC1 and degradation state SOH1 are input values ​​calculated by ECU50. The voltage Vb2 and temperature Tb2 of each battery pack 39a are input via communication through the battery pack ECU398 of each battery pack 39a, based on values ​​detected by the voltage sensor 398a and temperature sensor 398c of each battery pack 39a. The charge level SOC2 and degradation state SOH2 of each battery pack 39a are input via communication based on values ​​calculated by the battery pack ECU398 of each battery pack 39a.

[0018] Subsequently, it is determined whether the second battery 39 is selected as the battery to be used by the user based on the input of the display 70 (S110). When the user wants to increase the driving distance, it is considered that the second battery 39 is actively used. In addition, since the second battery 39 is detachable, for example, when used at a campsite, it may be used as a power source for other electrical devices at the destination without 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 to be used by the user based on the input of the display 70.

[0019] When the second battery 39 is selected in S110, it is determined whether each battery pack 39a constituting the second battery 39 is mounted (S120). When each battery pack 39a is mounted, it is determined whether the temperature Tb2 of each battery pack 39a is not less 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).

[0020] In S130, if the temperature Tb2 of all battery packs 39a is above the lower limit temperature Tbmin, it is determined that the second battery 39 (each battery pack 39a) is at a suitable temperature for use, and it is determined whether the second battery 39 is normal (first condition) or not (S140). This determination is made when two conditions are met: the voltage Vb2 of each battery pack 39a is within the normal voltage range, and the degradation state SOH2 is below a value indicating that the battery pack 39a is significantly degraded. In S140, if the second battery 39 is normal, it is determined whether the charge level SOC2 of each battery pack 39a is within the allowable range of lower limit SOC2min or higher and upper limit SOC2max or lower (second condition) (S150). The lower limit SOC2min and upper limit SOC2max are predetermined values ​​as the lower and upper limits of the charge level that are allowed when using the battery pack 39a. In S150, if the charge level SOC2 is within the acceptable range, it is determined whether the temperature Tb2 of each battery pack 39a is higher than the temperature Tb1 of the first battery 36 (third condition) (S160). In S160, if the temperature Tb2 of each battery pack 39a is higher than the temperature Tb1 of the first battery 36, it is determined whether the temperature Tb1 of the first battery 36 is in the warm-up-free range, which is higher than or equal to the starting temperature Tbst (e.g., -12°C, -10°C, -8°C, etc.), which is the lower limit of the temperature at which the first battery 36 can be used without warming up (fourth condition) (S170). If the temperature Tb1 of the first battery 36 is below the starting temperature Tbst, the second battery 39 is used when the system starts up, and even if the first battery 36 is to be used when the charge level SOC of the second battery 39 becomes low, it may not be possible to use the first battery 36 without warming it up. S170 is a decision made in consideration of these factors, and it determines whether the first battery 36 can be used without warming up after the second battery 39 has been used. If the temperature Tb1 of the first battery 36 is equal to or greater than the starting temperature Tbst in S170, the transistor 35 is turned off to disconnect the power line 38 from the first battery 36, and the disconnection devices 394 for each battery pack 39a are turned on to connect the power line 38 from the second battery 39 (S180), and the startup processing routine is terminated.Through this process, the power line 38 and the second battery 39 are connected when the system starts up, and the second battery 39 is used after the system starts up. In this way, when the temperature Tb2 of all battery packs 39a is above the lower limit temperature Tbmin and the conditions of S140 to S170 are met, the use of the second battery 39 is prioritized over the use of the first battery 36, and the use of the first battery 36 is suppressed, thus suppressing the warming up of the first battery 36. This reduces the power consumption required for warming up the batteries.

[0021] When the second battery 39 is not selected in S110, when each battery pack 39a is not mounted in S120, when the temperature Tb2 of any one of the battery packs 39a is less than the lower limit temperature Tbmin in S130, or when all the battery packs 39a have a temperature Tb2 of the lower limit temperature Tbmin or higher in S130 but the conditions of S140 to S170 are not satisfied, it is determined that it is better to use the first battery 36 rather than the second battery 39, and it is determined whether the first battery 36 is normal (S190). This determination is made when two conditions, that is, 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 a value indicating that the first battery 3 has deteriorated significantly, are satisfied. 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 the lower limit ratio SOC1min or higher and the upper limit ratio SOC1max or lower (S200). The lower limit ratio SOC1min and the upper limit ratio SOC1max are values predetermined as the lower limit value and the upper limit value of the power storage ratio allowed when using the first battery 36. When the power storage ratio SOC1 is within the allowable range in S200, the transistor 35 is turned on to connect the power line 38 and the first battery 36, the connection release device 394 of each battery pack 39a is turned off to release the connection between the power line 38 and the second battery 39, and the electrical device 37 is operated to warm up the first battery 36 by the heat generation of the internal resistance of the first battery 36 (S210), and the startup processing routine is terminated. Through 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. Thus, when the temperature Tb2 of any one of the battery packs 39a is less than the lower limit temperature Tbmin and the conditions of S190 to S210 are satisfied, the first battery 36 can be used. At this time, since the first battery 36 is warmed up, the first battery 36 can be used in a good state.

[0022] If the first battery 36 is not functioning correctly in S190, or if the charge level SOC1 is outside the acceptable range in S200, it is determined that the first battery 36 should not be used, and the system startup is prohibited (S220), and the startup processing routine is terminated. If the first battery 36 is not functioning correctly or the charge level SOC1 is outside the acceptable range, there is a possibility that the electric vehicle 20 may become unable to operate after starting to drive using the first battery 36 but before reaching its destination. By prohibiting the system startup when the first battery 36 is not functioning correctly or the charge level SOC1 is outside the acceptable range, it is possible to prevent the electric vehicle 20 from becoming unable to operate after starting to drive but before reaching its destination.

[0023] Next, we will explain the operation of the electric vehicle 20 when the system is shut down. Figure 4 is a flowchart showing an example of a shutdown processing routine executed by the ECU 50. The shutdown processing routine is executed when the start switch 60 is pressed and a system shutdown instruction is given while the system is running.

[0024] When the shutdown processing routine is executed, the CPU of the ECU 50 performs the process of inputting the ambient temperature Tatm detected by the temperature sensor 68 (S300). Next, it determines whether the second battery 39, i.e., each battery pack 39a, is installed (S310), and whether the ambient temperature Tatm is below a predetermined temperature Tlow (S320). The predetermined temperature Tlow is the ambient temperature threshold at which the second battery 39 will deteriorate if left attached to the power line 38, and is set to, for example, -20°C, -15°C, or -10°C. If each battery pack 39a is not installed, or if each battery pack 39a is installed but the ambient temperature Tatm exceeds the predetermined temperature Tlow, the shutdown processing routine is terminated.

[0025] If, in S310, each battery pack 39a is installed, and in S320, the ambient temperature Tatm is below a predetermined temperature Tlow, the system determines that the second battery 39 should not be left unattended, and outputs a voice message from speaker 69 indicating that the second battery 39 is installed (S330), and terminates the shutdown processing routine. This process informs the user that the second battery 39 is installed and prompts the user to remove each battery pack 39a of the second battery 39. This reduces the risk of forgetting to remove each battery pack 39a and allows the second battery 39 to be stored more reliably in a warm place such as indoors. As a result, the temperature of the second battery 39 can be kept within the acceptable temperature range when the system starts up, allowing the system to more appropriately prioritize connecting the second battery 39 to the power line 38 over the first battery 36, prioritizing the use of the second battery 39 over the first battery 36, and suppressing power consumption for warming up the first battery 36. In addition, in the case of S330, if it is determined that the second battery 39 should not be left unattended, a message indicating that the second battery 39 is installed may be displayed on the display 70.

[0026] According to the electric vehicle 20 of the embodiment described above, when a system start command is given, if the temperature Tb2 of the second battery 39 is within the allowable temperature range of lower limit temperature Tbmin or higher, the transistor 35 and the disconnection device 394 are controlled so that the second battery 39 is prioritized over the first battery 36 and connected to the power line 38, thereby suppressing power consumption for warming up the first battery 36.

[0027] Furthermore, when a system start command is issued and the temperature Tb2 of each battery pack 39a is within the allowable temperature range, and the predetermined connection conditions including steps S140 to S170 are met, the transistor 35 and the disconnection device 394 are controlled so that the connection between the power line 38 and the first battery 36 is released and the power line 38 and the second battery 39 are connected. When the predetermined connection conditions are not met, the transistor 35 and the disconnection device 394 are controlled so that the power line 38 and the first battery 36 are connected and the connection between the power line 38 and the second battery 39 is released, and the electrical equipment 37 is operated to warm up the first battery 36. This allows for a more appropriate connection of the second battery 39 to the power line 38 prioritizing its use over the first battery 36.

[0028] Furthermore, since the predetermined connection conditions are met when all of steps S140 to S170 are met, it is possible to more appropriately prioritize the connection of the second battery 39 to the power line 38 over the first battery 36, thereby prioritizing the use of the second battery 39 over the first battery 36.

[0029] Furthermore, when a system start command is issued and the temperature Tb2 of the second battery 39 is below the lower limit temperature Tbmin and outside the allowable temperature range, or when a system start command is issued and the temperature of the second battery 39 is within the allowable temperature range of lower limit temperature Tbmin or higher and the predetermined connection conditions including S140 to S170 are not met, if the first battery 36 is normal and the charge level SOC of the first battery 36 is within the allowable rate range of the first battery 36, the transistor 35 and the disconnection device 394 are controlled to connect the power line 38 to the first battery 36 and disconnect the power line 38 to the second battery 39, and the electrical equipment 37 is operated to warm up the first battery 36. If the first battery 36 is not normal or the charge level SOC1 of the first battery 36 is outside the allowable rate range of the first battery 36, system start is prohibited, thereby preventing the electric vehicle 20 from becoming unable to run before reaching its destination after starting to drive.

[0030] Furthermore, the system is equipped with a speaker 69 as an information notification device, and when the system is stopped and the second battery 39 is installed, the speaker 69 is controlled to notify that the second battery 39 is installed. This allows for more appropriate connection of the second battery 39 to the power line 38, prioritizing the use of the second battery 39 over the first battery 36, and suppressing power consumption for warming up the first battery 36.

[0031] In the above-described embodiment, the first battery 36 is designed so that it cannot be removed by the user and transported indoors. However, as illustrated by the first battery 136 of the electric vehicle 120 of another embodiment in Figure 5, instead of the first battery 36, a first battery 136 may be used in which two portable battery packs 39a, which are removable and transportable indoors by the user, are connected in series, similar to the second battery 39, and the overall rated voltage is set to several hundred volts. In this case, the first battery 136 is not warmed up by the electrical equipment 37. In the electric vehicle 120 of the other embodiment, when a system start command is given, the startup processing routine illustrated in Figure 6 is executed instead of the startup processing routine illustrated in Figure 3.

[0032] When the startup processing routine shown in Figure 6 is executed, the CPU of the ECU 50 performs the process of inputting the voltage Vb2, temperature Tb2, charge level SOC2, and degradation state SOH2 of each battery pack 39a of the first and second batteries 136 and 39 (S400). The voltage Vb2 and temperature Tb2 of each battery pack 39a are input via communication through the battery pack ECU 398 of each battery pack 39a, based on values ​​detected by the voltage sensor 398a and temperature sensor 398c of each battery pack 39a. The charge level SOC2 and degradation state SOH2 of each battery pack 39a are input via communication based on values ​​calculated by the battery pack ECU 398 of each battery pack 39a.

[0033] Next, it is determined whether all battery packs 39a constituting the first and second batteries 136 and 39 are installed (S410). If all battery packs 39a are installed, it is determined whether the temperature Tb2 of all battery packs 39a is equal to or greater than the starting temperature Tbst (S420). If the temperature Tb2 of all battery packs 39a is equal to or greater than the starting temperature Tbst in S420, it is determined whether the first battery 136 is normal (S430). This determination is made when two conditions are met: 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 less than the value indicating that the battery pack 39a is significantly degraded. In S430, if the first battery 136 is normal, it is determined whether the charge level SOC2 of each battery pack 39a of the first battery 136 is within the allowable range of between the lower limit SOC2min and the upper limit SOC2max (S440). In S440, if the charge level SOC2 is within the allowable range, it is determined whether the lowest temperature Tb2low1 of the temperatures Tb2 of each battery pack 39a of the first battery 136 is higher than the lowest temperature Tb2low2 of the temperatures Tb2 of each battery pack 39a of the second battery 39 (S450). When temperature Tb2low1 is higher than temperature Tb2low2, it is determined that it is better to use the first battery 136 rather than the second battery 39, so the disconnection devices 394 for each battery pack 39a of the first battery 136 are turned on to connect the power line 38 to the first battery 36, and the disconnection devices 394 for each battery pack 39a of the second battery 39 are turned off to disconnect the power line 38 to the second battery 39 (S460), and the startup processing routine is terminated.

[0034] If S430 to S450 are not met, the system determines whether the second battery 39 is functioning correctly using the same process as S140 of the startup processing routine exemplified in Figure 3 (S470). If the second battery 39 is functioning correctly, the system determines whether the charge level SOC2 of each battery pack 39a of the second battery 39 is within the acceptable range of SOC2min or higher and SOC2max or lower, using the same process as S150 of the startup processing routine exemplified in Figure 3 (S480). If the charge level SOC2 is within the acceptable range in S480, the system determines that it is better to use the second battery 39 as a priority over the first battery 136, and turns off the disconnection devices 394 of each battery pack 39a of the first battery 136 to disconnect the power line 38 from the first battery 36, while simultaneously turning off the disconnection devices 394 of each battery pack 39a of the second battery 39 to connect the power line 38 from the second battery 39 (S490), and terminates the startup processing routine.

[0035] If, in S410, none of the battery packs 39a are installed; in S420, the temperature Tb2 of any of the battery packs 39a is below the starting temperature Tbst; in S470, the second battery 39 is not functioning correctly; or in S480, the charge level SOC2 is outside the acceptable range, the system determines that the first and second batteries 136 and 39 should not be used, prohibits system startup (S500), and terminates the startup processing routine. This process helps to prevent the electric vehicle 20 from becoming unable to operate after starting to drive but before reaching its destination.

[0036] In the embodiments described above, steps S140 to S170 are executed, but it is possible to select and execute some of these four processes and not execute the processes that are not selected. In the embodiments described above, the shutdown processing routine illustrated in Figure 4 is executed when the system is stopped, but it is possible to not execute the shutdown processing routine. In the embodiments described above, the disadvantages of the first and second batteries 36 and 39 of this disclosure at low temperatures are addressed, but disadvantages at high temperatures may also be addressed. In this case, for example, S130 may be changed to check whether the temperature Tb2 of each battery pack 39a is below the upper limit temperature Tmax, which is within the allowable temperature range, or other appropriate changes may be made. In the embodiments described above, the second battery 39 is configured as two battery packs 39a connected in series. However, the second battery 39 may be configured as three or more battery packs 39a connected in series, or the second battery 39 may be configured as one battery pack 39a, or the second battery 39 may be configured as multiple battery packs 39a connected in parallel.

[0037] Furthermore, the correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem is merely an example to specifically explain the form in which the embodiment implements the invention described in the section on means for solving the problem, and does not limit the elements of the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the embodiment is merely one specific example of the invention described in the section on means for solving the problem.

[0038] While embodiments for implementing this disclosure have been described above, this disclosure is not limited in any way to these embodiments, and can of course be implemented in various forms without departing from the gist of this disclosure. [Explanation of Symbols]

[0039] 36 First battery, 39 Second battery, 39a battery pack, 50 ECU.

Claims

1. An electric vehicle comprising: a motor for driving; an inverter for driving the motor; a first battery; electrical equipment powered by electricity from the first battery; a detachable, portable second battery; a first disconnection device for connecting and disconnecting a power line connected to the inverter from the first battery; a second disconnection device for connecting and disconnecting the power line from the second battery; and a control device for controlling the first disconnection device and the second disconnection device, When a system start command is issued and the temperature of the second battery is within the allowable temperature range of the second battery, the control device controls the first and second disconnection devices so that the connection between the power line and the first battery is released and the power line and the second battery are connected when predetermined connection conditions are met, and when the predetermined connection conditions are not met, the control device controls the first and second disconnection devices so that the power line and the first battery are connected and the connection between the power line and the second battery is released, and also operates the electrical equipment to warm up the first battery. The predetermined connection conditions are that all of the following four conditions are met: a first condition that the second battery is functioning normally; a second condition that the charge level of the second battery is within the allowable charge level range for 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 warm-up-free range for use without warming up the first battery. Electric vehicle.

2. An electric vehicle comprising: a motor for driving; an inverter for driving the motor; a first battery; electrical equipment powered by electricity from the first battery; a detachable, portable second battery; a first disconnection device for connecting and disconnecting a power line connected to the inverter from the first battery; a second disconnection device for connecting and disconnecting the power line from the second battery; and a control device for controlling the first disconnection device and the second disconnection device, When a system start command is issued and the temperature of the second battery is within the allowable temperature range of the second battery, the control device controls the first and second disconnection devices so that the connection between the power line and the first battery is released and the power line and the second battery are connected when predetermined connection conditions are met, and when the predetermined connection conditions are not met, the control device controls the first and second disconnection devices so that the power line and the first battery are connected and the connection between the power line and the second battery is released, and also operates the electrical equipment to warm up the first battery. Furthermore, The control device, when the system start command is issued and the temperature of the second battery is outside the allowable temperature range, or when the system start command is issued and the temperature of the second battery is within the allowable temperature range and the predetermined connection conditions are not met, controls the first and second disconnection devices to connect the power line to the first battery and disconnect the power line to the second battery, and operates the electrical equipment to warm up the first battery, when the first battery is not normal or the charge level of the first battery is outside the allowable temperature range, prohibits the system start. Electric vehicle.

3. An electric vehicle according to claim 1 or 2, Equipped with a notification device to broadcast information. The control device controls the notification device to notify information that the second battery is installed when the system is stopped and the second battery is installed. Electric vehicle.

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