Power supply system for electrically-powered vehicle

Abstract

Provided is a power supply system for an electrically-powered vehicle, which can reduce the harshening of the environment in the passenger compartment of the vehicle upon detection of a collision of the electrically-powered vehicle. The power supply system is mounted on an electrically-powered vehicle comprising a battery that accumulates electricity for traveling and an electric device that is driven by the electricity of the battery and that includes an electrically-powered air conditioner. The power supply system comprises: an electric circuit that transmits the electricity from the battery to the electric device; a switch that is mounted on the electric circuit; and a controller that controls the switch to a state in which the electricity transmission from the battery to the electric device is stopped, upon detection of a collision of the electrically-powered vehicle. Upon detection of a collision of the electrically-powered vehicle, the controller: performs a determination process regarding air conditioning control in the passenger compartment; controls the switch on the basis of a result of the determination process so that the electricity from the battery to the electrically-powered air conditioner is transmitted; and drives the electrically-powered air conditioner.

Description

Electric vehicle power supply system

[0001] The present invention relates to a power supply system for an electric vehicle.

[0002] Patent Document 1 describes a vehicle power supply device in which a motor control device discharges on-board equipment using power from a backup power supply when a vehicle collision signal is received.

[0003] Japanese Patent Application Laid-Open No. 2021-035092

[0004] If the battery power becomes completely unusable after a vehicle collision, the interior of the vehicle may become a harsh environment in extreme cold or under the blazing sun.

[0005] An object of the present invention is to provide a power supply system for an electric vehicle that can reduce the harsh environment inside the vehicle cabin when a collision of the electric vehicle is detected.

[0006] One aspect of the present invention is a power supply system for an electric vehicle that is mounted on an electric vehicle having a battery that stores power for driving the vehicle and electrical equipment that is powered by the power of the battery, the electrical equipment including an electric air conditioner, the power supply system comprising: an electrical circuit that transmits power from the battery to the electrical equipment; a switch provided on the electrical circuit; and a controller that controls the switch to a state in which power transmission from the battery to the electrical equipment is stopped when a collision of the electric vehicle is detected, wherein the controller performs a determination process regarding air conditioning control for the passenger compartment when a collision of the electric vehicle is detected, and based on the result of the determination process, controls the switch so that power is transmitted from the battery to the electric air conditioner, thereby driving the electric air conditioner.

[0007] According to the present invention, it is possible to obtain an effect of reducing the harsh environment inside the vehicle cabin when a collision of the electric vehicle is detected.

[0008] 1 is a block diagram showing an electric vehicle equipped with a power supply system according to an embodiment of the present invention; FIG. 2 is a circuit diagram showing the power supply system of FIG. 1; FIG. 3 is a circuit diagram showing an example of a connection state of electrical paths after a collision is detected; FIG. 4 is a part of a flowchart showing an example of a control process executed by a controller; and FIG. 5 is a circuit diagram showing a modified example of an electrical path of the power supply system according to an embodiment.

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0010] Fig. 1 is a block diagram showing an electric vehicle equipped with a power supply system according to an embodiment of the present invention. Fig. 2 is a circuit diagram showing the power supply system shown in Fig. 1. In Fig. 1, an electric circuit L of the power supply system is simplified.

[0011] An electric vehicle 1 equipped with a power supply system 30 of this embodiment includes drive wheels 2a, 2b, traction motors 3a, 3b that drive the drive wheels 2a, 2b, respectively, inverters 4a, 4b that drive the traction motors 3a, 3b, respectively, a battery 5 that stores power for driving, a driving operation unit 6 that receives driving operations from the driver, a controller 7 that controls the inverters 4a, 4b in response to signals from the driving operation unit 6, an electric air conditioner 8 that operates on power from the battery 5, a low-voltage battery 9 that supplies power supply voltage to low-voltage equipment, and a DC / DC converter 10 that receives power from the battery 5 and generates power supply voltage for the low-voltage equipment. The low-voltage equipment includes the controller 7.

[0012] The electric vehicle 1 further includes a first inlet 11 and a relay 12 for inputting a DC external power source to charge the battery 5, and a second inlet 13 and a charger 14 for inputting an AC external power source to charge the battery 5. The first inlet 11 is connected to the first electrical circuit L1 via the relay 12. The second inlet 13 is connected to the first electrical circuit L1 via the charger 14. The charger 14 converts the AC external power source into DC and sends it to the battery 5.

[0013] The electric vehicle 1 further includes an operation panel 21 that allows the rider to input commands, a communication unit 22 that can communicate with a service facility located at a remote location, a collision sensor 23 that detects a collision of the electric vehicle 1, and a position sensor 24 that measures the position of the electric vehicle 1. The communication unit 22 is configured to enable data communication between the service facility and the controller 7 in addition to communication that enables voice calls between the service facility and the rider. The collision sensor 23 is, for example, a sensor that detects the deployment of an airbag, but may be any other sensor that can detect a collision, such as an acceleration sensor. The position sensor 24 measures the position of the electric vehicle 1 using, for example, a positioning system including a positioning satellite.

[0014] The drive wheels 2a are, for example, two front wheels, and the drive wheels 2b are, for example, two rear wheels. Note that one of the traction motors 3a, 3b and one of the inverters 4a, 4b may be omitted, and the front wheels or the rear wheels may be driven wheels.

[0015] The driving operation unit 6 includes a steering unit 6a such as a steering wheel, a braking operation unit 6b such as a brake pedal, and an acceleration operation unit 6c such as an accelerator pedal. The driving operation unit 6 is configured to be operable by the driver, but may also be configured to be operated by an automated driving system.

[0016] The battery 5 is, for example, a lithium ion secondary battery, a nickel-metal hydride secondary battery, or the like, but is not particularly limited to this type. The battery 5 outputs a higher voltage (for example, 100 V or higher) than the low-voltage battery 9. The low-voltage battery 9 is, for example, a lead battery, but is not particularly limited to this type. The low-voltage battery 9 outputs a lower voltage (for example, a 12 V system voltage) than the battery 5.

[0017] The electric air conditioner 8 includes an electric heater 8b and an electric compressor 8a. The electric air conditioner 8 can raise the temperature in the vehicle cabin by sending air heated by the electric heater 8b to the vehicle cabin. The electric air conditioner 8 can lower the temperature in the vehicle cabin by driving the electric compressor 8a to operate as a heat pump and sending cooled air to the vehicle cabin. The vehicle cabin refers to the space in the electric vehicle 1 where a person rides.

[0018] The controller 7 corresponds to an example of a controller according to the present invention included in the power supply system 30. The controller 7 is a microcomputer such as an ECU (Electronic Control Unit) and operates according to a control program stored in a memory unit 7a. The controller 7 receives signals from the driving operation unit 6 and controls the inverters 4a and 4b to control the driving of the electric vehicle 1 (referred to as "driving control"). In addition, the controller 7 controls air conditioning to adjust the temperature in the vehicle compartment. The air conditioning control is performed based on commands from the operation panel 21 or based on conditions that do not depend on the operation of the passenger. In addition, the controller 7 controls switching of the electric circuit L by switching the states of switches SW1 to SW3 provided in the electric circuit L. In addition, the controller 7 performs control based on collision detection of the electric vehicle 1.

[0019] The travel control, air conditioning control, switching control of the electric line L, and control based on collision detection may be performed by multiple controllers communicating with each other and coordinating with each other, rather than by a single controller 7. In this case, the controllers that perform the air conditioning control, switching control of the electric line L, and control based on collision detection correspond to an example of a controller according to the present invention included in the power supply system 30.

[0020] <Electrical Circuit and Switch> Figures 2 and 3 are circuit diagrams showing the power supply system of Figure 1. Figure 2 shows the state of the electrical circuit L during normal operation, and Figure 3 shows an example of the connection state of the electrical circuit L after a collision is detected. In Figures 2 and 3, the current flowing from the positive pole of the battery 5 is indicated by a thick arrow.

[0021] The power supply system 30 includes an electric line L that transmits power between the battery 5 and multiple electrical devices, and switches SW1 to SW3 provided on the electric line L. The power supply system 30 may further include a blow-out fuse F1 that is connected in series to or built into the battery 5. Hereinafter, a state in which the switches SW1 to SW3 disconnect the electric line will be referred to as the switches SW1 to SW3 being off, and a state in which the switches SW1 to SW3 connect the electric line will be referred to as the switches SW1 to SW3 being on. Of the multiple switches SW1 to SW3, the switch SW1 corresponds to an example of a first switch according to the present invention. The switch SW2 corresponds to an example of a second switch according to the present invention. The switch SW3 corresponds to an example of a third switch according to the present invention.

[0022] The plurality of electrical devices include the inverters 4 a and 4 b, the first inlet 11, the charger 14, the DC / DC converter 10, and the electric air conditioner 8 described above.

[0023] The electrical circuit L includes a first electrical circuit L1 that can transmit power between the battery 5 and multiple electrical devices under normal conditions, and a second electrical circuit L2 that is used exclusively to transmit power from the battery 5 to the electric air conditioner 8 after a collision is detected.

[0024] The switches SW1 to SW3 include a switch SW1 which is a system main relay provided on the first electrical circuit L1, a switch SW2 which can disconnect the second electrical circuit L2, and a switch SW3 which can disconnect the first electrical circuit L1 and the second electrical circuit L2. The switch SW1 corresponds to an example of a first switch according to the present invention. The switch SW2 corresponds to an example of a second switch according to the present invention. The switch SW3 corresponds to an example of a third switch according to the present invention.

[0025] Each of the first electrical path L1 and the second electrical path L2 has a pair of electric wires to which the anode and cathode of the battery 5 are respectively connected.

[0026] Each of the switches SW1 to SW3 includes a pair of switches capable of disconnecting one of the pair of electric wires. Furthermore, the switches SW1 and SW2 may include a pre-charge switch that reduces inrush current from the battery 5 to the electric device by inserting a resistor R1 when the electric path is connected. Each switch is a relay, but various switches such as a contactor or a power semiconductor switch may also be used as long as they can interrupt the transmission of power.

[0027] The state of the electrical circuit L configured as above is switched as follows under the control of the switches SW1 to SW3.

[0028] <During Pause> When the system of the electric vehicle 1 is paused, the switches SW1 and SW2 are turned off and the switch SW3 is turned on, thereby causing the first electrical circuit L1 and the second electrical circuit L2 to be cut off so that power is not transmitted between the battery 5 and the plurality of electrical devices.

[0029] <During Normal Operation> During normal operation of the electric vehicle 1, as shown in Fig. 2, the switch SW1 is turned on, the switch SW3 is kept on, and the switch SW2 is kept off, thereby enabling power to be transmitted between the battery 5 and multiple electrical devices via the first electrical circuit L1. At this time, the second electrical circuit L2 is kept in a cut-off state so that power is not transmitted via the second electrical circuit L2. Normal operation refers to a period during which the electric vehicle 1 is in a normal state and the system of the electric vehicle 1 is activated, and corresponds to, for example, a period during which the electric vehicle 1 is running in a normal state, a period during which it is capable of running, a period during which charging control is being performed, etc. The normal state refers to a state in which no abnormality, such as collision detection, occurs.

[0030] <When an abnormality occurs> When an abnormality occurs in the electric vehicle 1, the switch SW1 is turned off, and the switch SW2 is kept off and the switch SW3 is kept on, thereby disconnecting the plurality of electrical devices and most of the first and second electrical circuits L1 and L2 from the battery 5. An abnormality may occur when a collision of the electric vehicle 1 is detected, for example.

[0031] <After Abnormality Occurrence> After an abnormality occurs in the electric vehicle 1, when a predetermined condition described below is satisfied, as shown in Fig. 3 , the switch SW2 is turned on, the switch SW3 is turned off, and the switch SW1 is kept off, thereby enabling power from the battery 5 to be transmitted to the electric air conditioner 8 via the second electrical path L2. In this state, electrical devices other than the electric air conditioner 8 (such as the inverters 4a, 4b, the DC / DC converter 10, or both) are disconnected from the battery 5.

[0032] The second electrical circuit L2 may be configured to be shorter than the first electrical circuit L1, and because it is shorter, it may be provided in a location that is less susceptible to the impact of a collision of the electric vehicle 1 than the first electrical circuit L1. With this configuration, even if a failure occurs in the first electrical circuit L1 due to a collision of the electric vehicle 1, power can be supplied from the battery 5 to the electric air conditioner 8 via the second electrical circuit L2. Furthermore, even if a high voltage is output to the second electrical circuit L2, it is possible to reduce the possibility that this high voltage will interfere with the recovery of the electric vehicle 1 from the failure.

[0033] The power supply system 30 further includes a discharge switch SW11 that connects the anode and cathode wires of the first electrical circuit L1 via a discharge resistor R2. The discharge resistor R2 has a sufficiently large resistance value, and when the discharge switch SW11 is turned on, the anode and cathode wires of the first electrical circuit L1 are electrically connected via the discharge resistor R2. The discharge switch SW11 and resistor R2 are configured to discharge any remaining charge in the first electrical circuit L1 and between the terminals of the electrical equipment when the switch SW1 is turned off. Even after the switch SW1 is turned off, high voltage remains between the terminals of the electrical equipment due to internal capacitors, etc. The discharge switch SW11 and discharge resistor R2 allow the high voltage to be slowly removed (e.g., over 10 minutes).

[0034] The discharge switch SW11 and the discharge resistor R2 may be provided in the first electrical path L1 or may be provided inside the electrical device.

[0035] <Services in the Event of a Collision> When a collision of the electric vehicle 1 is detected, the service facility communicates with the electric vehicle 1 via the communication unit 22 to provide various services. For example, the service facility communicates with the electric vehicle 1 to confirm the status of the occupant and the electric vehicle 1. The service facility also receives location information of the electric vehicle 1 from the controller 7 of the electric vehicle 1 and requests a rescue team or the like to that location depending on the situation. The service facility can predict the time it will take for the rescue team to arrive at the location of the electric vehicle 1 based on the location information and information on the rescue team's dispatch point. The service facility also has information on the weather and temperature at each location, as well as their forecasts.

[0036] When the service facility detects a collision of the electric vehicle 1 and requests a rescue team or the like, it sends information about the time until the rescue team arrives and information about the weather and temperature at the location where the electric vehicle 1 is located to the controller 7 via communication.

[0037] <Fault Diagnosis> The controller 7 has a fault diagnosis function for the electric air conditioner 8. In this function, the controller 7 can diagnose whether there is a fault in the electric air conditioner 8 by sending commands to the control circuit of the electric air conditioner 8 and determining whether there is a normal response to the command from the control circuit. The above command includes a command requesting a response from the control circuit of the electric air conditioner 8, and the above response may be a response confirming whether the control circuit is operating. Furthermore, the above command may include a command to operate a moving part of the electric air conditioner 8 (such as a rotating part of the electric compressor 8a), and the above response may include a response indicating that the moving part has operated normally. Furthermore, the above command may include a command to pass a current through a driving part (such as the heating wire of the electric heater 8b), and the above response may include a response indicating that a normal current has flowed.

[0038] Furthermore, the controller 7 has a function of diagnosing a fault in the battery 5. The battery 5 is equipped with a sensor for detecting leakage current and a sensor for detecting heat generation. In this function, the controller 7 monitors the outputs of these sensors and checks whether abnormal leakage current, abnormal heat generation, etc. have been detected in the battery 5, thereby diagnosing whether there is a fault in the battery 5.

[0039] 4 and 5 show an example of a flowchart of the control process executed by the controller 7. When the controller 7 is started, it executes a process (step S1) of monitoring the detection of an impact exceeding a threshold value using an acceleration sensor or the like, and repeats this process while no impact exceeding the threshold value is detected. If an impact exceeding the threshold value is detected, the controller 7 proceeds to step S2.

[0040] As a result, when the processing progresses, the controller 7 determines whether the airbag has been deployed by determining the detection result of the collision sensor 23 (step S2). The detection of the deployment of the airbag corresponds to the detection of a collision of the electric vehicle 1. If the airbag has not been deployed, the controller 7 returns the processing to step S1 again.

[0041] On the other hand, if the airbag has deployed, the controller 7 notifies a service facility of the collision via the communication unit 22 (step S3). This notification is an automatic notification that does not require any operation by the occupant. Furthermore, the controller 7 switches the switch SW1 to OFF, thereby switching to a state in which power transmission from the battery 5 to the electrical devices is stopped (step S4). Furthermore, the controller 7 switches the discharge switch SW11 to ON, thereby starting discharging of the first electrical circuit L1 (step S4). Here, if each of the multiple electrical devices includes a discharge circuit, the controller 7 may send a command to each electrical device to activate the discharge circuit, thereby starting discharging.

[0042] Next, the controller 7 executes a determination process (specifically, steps S5, S6, S8, and S9 described below) regarding air conditioning control for the passenger compartment of the electric vehicle 1. The determination regarding air conditioning control includes determining whether air conditioning control is necessary, determining whether air conditioning control is possible, and determining the air conditioning control settings (cooling, heating, intensity, etc.). The determination process of steps S5 and S6 corresponds to an example of a first determination process according to the present invention, and the determination process of steps S8 and S9 corresponds to an example of a second determination process according to the present invention.

[0043] Here, the controller 7 determines whether air conditioning control is necessary by executing steps S5 and S6. Specifically, the controller 7 first estimates the change in cabin temperature when the electric air conditioner 8 is not driven (step S5). Here, the controller 7 estimates the change in cabin temperature before the arrival of a rescue team or the like. The controller 7 acquires information on the estimated time until the arrival of a rescue team or the like from a service facility, and estimates the cabin temperature from the current cabin temperature, weather, and outside air information using an estimation function or data table. Note that one purpose of estimating the cabin temperature is to estimate whether the cabin environment in which the occupants will remain will be severe. Therefore, the controller 7 may estimate the value of the cabin temperature after a predetermined time, rather than the change in cabin temperature before the arrival of a rescue team or the like, or may estimate whether the cabin temperature will become severe, rather than the value of the cabin temperature.

[0044] Next, the controller 7 determines whether the passenger compartment temperature after the change estimated in step S5 is outside the first temperature range, i.e., whether the temperature is too low (step S6). That is, the lower limit of the first temperature range may be set to a threshold value representing an extremely low temperature, such as a value between −15° C. and 0° C., and the upper limit of the first temperature range may be set to a threshold value representing an extremely high temperature, such as a value between 35° C. and 50° C.

[0045] If the determination result in step S6 is NO (within the first temperature range), the controller 7 maintains the state of the power supply system 30 at this time and ends the control process.

[0046] On the other hand, if the determination result in step S6 is YES (outside the first temperature range), the controller 7 drives the electric air conditioner 8 using the charge remaining in the first electrical circuit L1 and being discharged as power (step S7). If the passenger compartment temperature is predicted to be low, the electric air conditioner 8 is driven to provide a heating function, and if the passenger compartment temperature is predicted to be high, the electric air conditioner 8 is driven to provide a cooling function. The inverters 4a and 4b are provided with relatively large capacitors, and the electric charge stored in these capacitors can be used to drive the electric air conditioner 8. The processing in step S7 allows the electric charge that would have been discharged to be effectively utilized.

[0047] Next, the controller 7 determines whether air conditioning control using power from the battery 5 is possible in steps S8 and S9. That is, the controller 7 first performs a fault diagnosis of the electric air conditioner 8 and a fault diagnosis of the battery 5 (step S8). The details of the fault diagnosis are as described above, and the fault diagnosis of the battery 5 includes detection of a ground leak. Next, the controller 7 determines the results of the diagnosis (step S9).

[0048] If the determination result in step S9 is abnormal, the controller 7 ends the control process while maintaining the current state of the power supply system 30. Thereafter, the battery 5 remains disconnected from the plurality of electrical devices, and the first electrical circuit L1 continues to discharge, and the power supply system 30 reaches a state corresponding to the state after a collision of the electric vehicle 1.

[0049] On the other hand, if the determination result in step S9 is normal, the controller 7 turns off the switch SW3 and turns on the switch SW2 (step S10). Note that a normal fault diagnosis result is not limited to a state in which there is no abnormality at all. For example, a normal result for the battery 5 means a diagnosis result that the battery 5 can output power. Also, a normal result for the electric air conditioner 8 means a diagnosis result that the electric air conditioner 8 can be driven.

[0050] 3 , the processing of step S10 disconnects the power supply electric circuit of the electric air conditioner 8 from the first electric circuit L1, and power is supplied to the electric air conditioner 8 from the battery 5 via the second electric circuit L2. The electric air conditioner 8 is then driven by the power of the battery 5. In step S10, the controller 7 may use a pre-charge switch to perform switching control of the switch SW2, which reduces inrush current from the battery 5. Even when the processing of step S10 is performed, the discharge of the first electric circuit L1 continues, and it is possible to prevent a high voltage from remaining in the first electric circuit L1 and the electrical devices (such as the inverters 4a and 4b) connected to the first electric circuit L1.

[0051] Furthermore, the controller 7 performs a setting process for the electric air conditioner 8 based on the time until the arrival of a rescue team or the like and the remaining charge of the battery 5 (step S11). This setting process mainly sets the intensity of the air conditioning, and it is sufficient to set the intensity so as to prevent a situation in which the remaining charge runs out in a period shorter than the time until the arrival of the rescue team or the like, causing the temperature in the vehicle cabin to become too high. Then, the controller 7 ends this control process.

[0052] By the control process described above, when a collision of the electric vehicle 1 is detected and the battery 5 and the electric air conditioner 8 are normal, air conditioning control is performed as necessary to prevent the cabin temperature from becoming too high. Therefore, even if a collision of the electric vehicle 1 leaves passengers in the cabin, it is possible to reduce the discomfort that passengers may experience due to the cabin temperature.

[0053] The program for the above-described control process is stored in a non-transitory computer readable medium such as the storage unit 7a of the controller 7. The controller 7 may be configured to read and execute a program stored in a portable non-transitory recording medium. The portable non-transitory recording medium may store the program for the above-described control process.

[0054] As described above, according to the power supply system 30 of the electric vehicle 1 of this embodiment, the controller 7 performs a determination process related to the air conditioning control of the vehicle cabin when it detects a collision of the electric vehicle 1. Then, based on the result of this determination process, the controller 7 controls the switches SW2 and SW3 to transmit power from the battery 5 to the electric air conditioner 8, thereby driving the electric air conditioner 8. Therefore, even if a collision of the electric vehicle 1 causes the battery 5 to be disconnected and the occupants remain in the vehicle cabin, the electric air conditioner 8 can be driven by power from the battery 5 depending on the situation, thereby reducing the discomfort to the occupants caused by the temperature in the vehicle cabin.

[0055] Furthermore, according to the power supply system 30 of the electric vehicle 1 of this embodiment, one of the determination processes related to the air conditioning control is to estimate a change in the passenger compartment temperature when the electric air conditioner 8 is not driven, and determine whether the estimated passenger compartment temperature is outside the first temperature range. This determination process makes it possible to determine whether air conditioning control is necessary, and to avoid unnecessary air conditioning control after a collision of the electric vehicle 1 is detected.

[0056] Furthermore, according to the power supply system 30 of the electric vehicle 1 of this embodiment, as one of the determination processes related to the air conditioning control, a fault diagnosis of the electric air conditioner 8 and a fault diagnosis of the battery 5 are performed, and the results are judged. Therefore, when an abnormality occurs in the electric air conditioner 8 or the battery 5 due to a collision or the like, attempting to drive the electric air conditioner 8 with power from the battery 5 can be prevented from worsening the abnormality. Note that if it is known that the possibility of an abnormality occurring in the electric air conditioner 8 is extremely low, the fault diagnosis of the electric air conditioner 8 may be omitted. Similarly, if it is known that the possibility of an abnormality in the battery 5 is extremely low, the fault diagnosis of the battery 5 may be omitted.

[0057] Furthermore, according to the power supply system 30 of the electric vehicle 1 of this embodiment, after a collision is detected, the discharge switch SW11 performs a discharge process to release the electric charge remaining between the first electrical circuit L1 and the electrodes of the plurality of electrical devices. Furthermore, during this discharge process, depending on the conditions, the controller 7 temporarily drives the electric air conditioner 8 using the released electric charge, i.e., the discharge power. This process makes it possible to effectively utilize the electric charge remaining in the first electrical circuit L1 and the electrical devices before release, and further shortens the discharge time.

[0058] Furthermore, according to the power supply system 30 of the electric vehicle 1 of this embodiment, if the result of the determination process of steps S5 and S6 (corresponding to the first determination process) indicates that the cabin temperature is outside the first temperature range, the controller 7 drives the electric air conditioner 8 using the charge before discharging. Thereafter, if the result of the determination process of steps S8 and S9 (corresponding to the second determination process) is normal, the controller 7 drives the electric air conditioner 8 using the power of the battery 5. Even if there is an abnormality in the battery 5 or the electric air conditioner 8 due to a collision, controlling the drive of the electric air conditioner 8 during the discharge process is unlikely to exacerbate the abnormality. Therefore, according to the above processing procedure, it is possible to achieve drive control of the electric air conditioner 8 with little waste.

[0059] Furthermore, the power supply system 30 of the electric vehicle 1 of this embodiment includes a first electrical circuit L1 that transmits power from the battery 5 to the inverters 4a, 4b and the electric air conditioner 8, and a second electrical circuit L2 that can transmit power from the battery 5 to the electric air conditioner 8 excluding the inverters 4a, 4b. The power supply system 30 also includes a switch SW1 provided on the first electrical circuit L1, a switch SW2 provided on the second electrical circuit L2, and a switch SW3 that can disconnect the first electrical circuit L1 from the second electrical circuit L2. When driving the electric air conditioner 8 with power from the battery 5 after detecting a collision, the controller 7 switches the switches SW1 to SW3 so that the power from the battery 5 is transmitted to the electric air conditioner 8 via the second electrical circuit disconnected from the first electrical circuit. With this configuration, even when driving the electric air conditioner 8 with power from the battery 5 after detecting a collision of the electric vehicle 1, the high voltage on the first electrical circuit L1 can be removed by discharging. Therefore, it is possible to prevent problems after a collision is detected that would be caused by high voltage remaining in the first electrical circuit L1. Furthermore, the existence of the second electrical circuit L2 makes it possible to drive the electric air conditioner 8 even if a failure occurs due to a collision that prevents the switch SW1 from being turned on.

[0060] The above describes an embodiment of the present invention. However, the present invention is not limited to the above embodiment. For example, in the above embodiment, the electrical circuit L of the power supply system 30 includes the first electrical circuit L1 and the second electrical circuit L2. However, the electrical circuit L may not include the second electrical circuit L2, and power may be supplied from the battery 5 to the electric air conditioner 8 via the first electrical circuit L1 after a collision is detected. Alternatively, as shown in FIG. 6 , a configuration may be adopted in which the electric air conditioner 8 is connected upstream of the first electrical circuit L1 (i.e., closer to the battery 5), other electrical devices are connected downstream, and a switch SW4 is provided in the first electrical circuit L1 to disconnect the downstream side. FIG. 6 is a circuit diagram showing a modification of the electrical circuit of the power supply system according to the embodiment. In this configuration, by turning on the switch SW1 and turning off the switch SW4, power can be supplied from the battery 5 to the electric air conditioner 8, excluding the inverters 4a and 4b. Therefore, this state may be the state of the electrical circuit L when power is supplied from the battery 5 to the electric air conditioner 8 after a collision is detected. Furthermore, in the above embodiment, an example was shown in which control was performed to prevent the cabin temperature from becoming too high or too low. However, for an electric vehicle used in, for example, an extremely cold region, control may be performed to prevent the cabin temperature from becoming too low only. In this case, the electric air conditioner does not need to be configured to lower the cabin temperature. Conversely, for an electric vehicle used in, for example, a hot region, control may be performed to prevent the cabin temperature from becoming too high only. In this case, the electric air conditioner does not need to be configured to raise the cabin temperature. Other details shown in the embodiment may be modified as appropriate without departing from the spirit of the invention.

[0061] The present invention can be used in a power supply system for an electric vehicle.

[0062] REFERENCE SIGNS LIST 1 Electric vehicle 2a, 2b Drive wheels 3a, 3b Travel motor 4a, 4b Inverter 5 Battery 6 Driving operation unit 7 Controller 7a Memory unit 8 Electric air conditioner 8a Electric compressor 8b Electric heater 9 Low voltage battery 10 DC / DC converter 11 First inlet 12 Relay 13 Second inlet 14 Charger 21 Operation panel 22 Communication unit 23 Collision sensor 24 Position sensor 30 Power supply system L Electric circuit L1 First electric circuit L2 Second electric circuit SW1 to SW4 Switch SW11 Discharge switch R2 Discharge resistor

Claims

1. A power supply system for an electric vehicle to be mounted on an electric vehicle having a battery that stores power for driving and electric equipment to which power is transferred between the battery, the electric equipment including an electric air conditioner, comprising: an electric circuit that transfers power between the battery and the electric equipment; a switch provided on the electric circuit; and a controller that controls the switch to a state in which power transfer between the battery and the electric equipment is stopped when a collision of the electric vehicle is detected, wherein the controller performs a determination process regarding air conditioning control for the passenger compartment when a collision of the electric vehicle is detected, and based on the result of the determination process, controls the switch so that power is transferred from the battery to the electric air conditioner, thereby driving the electric air conditioner.

2. The power supply system of an electric vehicle as described in claim 1, characterized in that the judgment process includes a process of estimating a temperature change in the vehicle cabin when the electric air conditioner is not driven, and determining whether the estimated temperature change is outside a first temperature range.

3. The power supply system for an electric vehicle according to claim 1, wherein the judgment process includes a process for discriminating the results of a fault diagnosis of the electric air conditioner, a fault diagnosis of the battery, or a fault diagnosis of both of these.

4. The power supply system for an electric vehicle as described in claim 1, further comprising a discharge switch that discharges remaining charge in the electric equipment, and the controller detects a collision of the electric vehicle and temporarily drives the electric air conditioner using the charge remaining in the electric equipment while the charge is being discharged by the discharge switch.

5. The power supply system for an electric vehicle as described in claim 4, characterized in that the judgment process includes a first discrimination process that predicts a temperature change in the passenger compartment when the electric air conditioner is not driven and determines whether the temperature after the predicted change is outside a first temperature range, and a second discrimination process that discriminates the results of a fault diagnosis of the electric air conditioner and a fault diagnosis of the battery, wherein the controller, when the result of the first discrimination process is outside the first temperature range, temporarily drives the electric air conditioner using the charge remaining in the electrical equipment, and then, when the result of the second discrimination process is normal, drives the electric air conditioner using the power of the battery.

6. The power supply system of an electric vehicle as described in claim 1, characterized in that the electric equipment includes an inverter that drives a traction motor, the electric circuits include a first electric circuit capable of transmitting power from the battery to the inverter and the electric air conditioner, and a second electric circuit capable of transmitting power from the battery to the electric air conditioner excluding the inverter, the switches include a first switch provided on the first electric circuit, a second switch provided on the second electric circuit, and a third switch capable of disconnecting the first electric circuit from the second electric circuit, when the electric air conditioner is driven by power from the battery based on the result of the determination process, the controller transmits power from the battery to the electric air conditioner via the second electric circuit disconnected from the first electric circuit.

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