electric vehicles

Abstract

This allows for safe movement in the event of a malfunction in the series relay. [Solution] In the electric vehicle, during normal driving control, in which the series relay is turned on and the first and second inverters are controlled to run using power from the first and second batteries, if an open circuit abnormality occurs in the series relay, the electric vehicle will perform emergency driving control, in which one of the first and second parallel relays is turned on and the first and second inverters are controlled to run using power from one of the first and second batteries whose charge level is above a threshold.

Description

Technical Field

[0001] The present disclosure relates to electric vehicles.

Background Art

[0002] Conventionally, an electric vehicle that can be charged from an external charger of a power supply facility to first and second power storage modules via a power supply cable connected to a charging port has been proposed (see, for example, Patent Document 1). In this electric vehicle, in addition to the first and second power storage modules, a series-parallel switching relay capable of switching the connection states of the first and second power storage modules in series and parallel, a power converter for transferring power between the first and second power storage modules, and a vehicle-mounted control unit that executes a voltage equalization process for controlling the power converter so that the voltage difference between the first and second power storage modules becomes below a threshold value prior to parallel switching of the first and second power storage modules are provided. The vehicle-mounted control unit sets the open / closed state of the series-parallel switching relay to a predetermined diagnostic mode and diagnoses an abnormality of the series-parallel switching relay based on the detection value of a voltage detector that detects the voltage of the charging port.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In addition to the electric vehicle with the hardware configuration described above, an electric vehicle has also been devised that includes a battery system, a motor for driving with a three-phase open winding, a first inverter connected to the positive and negative lines to which the battery system is connected and connected to one end of the three-phase open winding, and a second inverter connected to the positive and negative lines and connected to the other end of the three-phase open winding. In this electric vehicle, the battery system may include a first battery having a first positive terminal and a first negative terminal connected to the positive line, a second battery having a second positive terminal and a second negative terminal connected to the negative line, a series line connected to the first negative terminal and the second positive terminal, a first parallel line connected to the first negative terminal and the negative line, a second parallel line connected to the second positive terminal and the positive line, a series relay provided on the series line, a first parallel relay provided on the first parallel line, and a second parallel relay provided on the second parallel line. In this case, a challenge for electric vehicles is how to perform emergency maneuvers if an open circuit malfunction occurs in the series relay while the vehicle is running using power from the first and second batteries with the series relay in the ON state.

[0005] The primary purpose of the electric vehicle disclosed herein is to enable it to move in a safe position when an open circuit malfunction occurs in the series relay. [Means for solving the problem]

[0006] The electric vehicle of this disclosure employs the following means to achieve the main objective described above.

[0007] The electric vehicle disclosed herein is A battery system comprising: a first battery having a first positive terminal connected to a positive terminal line and a first negative terminal; a second battery having a second positive terminal and a second negative terminal connected to a negative terminal line; a series line connected to the first negative terminal and the second positive terminal; a first parallel line connected to the first negative terminal and the negative terminal line; a second parallel line connected to the second positive terminal and the positive terminal line; a series relay provided on the series line; a first parallel relay provided on the first parallel line; and a second parallel relay provided on the second parallel line. A motor for traction having a 3-phase open winding, A first inverter connected to the positive electrode line and the negative electrode line and connected to one end of the three-phase open winding, A second inverter connected to the positive electrode line and the negative electrode line and connected to the other end of the three-phase open winding, A control device that controls the series relay, the first and second parallel relays, and the first and second inverters, An electric vehicle equipped with, If an open circuit abnormality occurs in the series relay while the control device is performing normal driving control, which controls the first and second inverters to run using power from the first and second batteries with the series relay in the ON state, it performs retraction driving control, which controls the first and second inverters to run using power from one of the first and second batteries, provided that the charge level is above a threshold, with one of the first and second parallel relays in the ON state. This is the gist of it.

[0008] In the electric vehicle of this disclosure, the control device performs normal driving control, which controls the first and second inverters to run using power from the first and second batteries with the series relay in the ON state, and if an open circuit abnormality occurs in the series relay, it performs emergency driving control, which controls the first and second inverters to run using power from one of the first and second batteries with a charge ratio above a threshold, by turning on one of the first and second parallel relays. This allows emergency driving to be performed when an open circuit abnormality occurs in the series relay.

[0009] In the electric vehicle of this disclosure, the control device may, as the retraction driving control, perform a first retraction driving control in which, when the charge level of the first battery is equal to or greater than a first threshold, the first parallel relay is turned on and the first and second inverters are controlled to drive using power from the first battery; and a second retraction driving control in which, when the charge level of the first battery is less than a first threshold and the charge level of the second battery is equal to or greater than a second threshold, the second parallel relay is turned on and the first and second inverters are controlled to drive using power from the second battery.

[0010] In this case, the battery system further includes a positive-side relay provided between the first battery on the positive-side line and the first and second inverters, and the control device may turn off the positive-side relay when executing the second retraction travel control. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram showing the general configuration of an electric vehicle according to an embodiment of the disclosure. [Figure 2] This is an explanatory diagram showing how voltage is applied to the first and second inverters during normal driving control. [Figure 3] This flowchart shows an example of a processing routine executed by the ECU. [Figure 4] This is an explanatory diagram showing how voltage is applied to the first and second inverters during the first retraction control. [Figure 5] This is an explanatory diagram showing how voltage is applied to the first and second inverters during the second retraction control. [Modes for carrying out the invention]

[0012] Embodiments for implementing this disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram showing the general configuration of an electric vehicle 10 according to an embodiment of this disclosure. As shown in the figure, the electric vehicle 10 of the embodiment includes a battery system 11, a motor 30, first and second inverters 32 and 34, first and second capacitors 36 and 38, a changeover switch 40, a system main relay SMR, and an electronic control unit (hereinafter referred to as "ECU") 50 (control device).

[0013] The battery system 11 comprises first and second batteries 13 and 14, a series line 23, first and second parallel lines 24 and 25, a series relay Rs, and first and second parallel relays Rp1 and Rp2. The first and second batteries 13 and 14 are configured as lithium-ion secondary batteries and nickel-metal hydride secondary batteries, respectively. In this embodiment, the first and second batteries 13 and 14 are of the same specifications.

[0014] The first positive terminal of the first battery 13 is connected to the positive terminal line 21. The second negative terminal of the second battery 14 is connected to the negative terminal line 22. The series line 23 is connected to the first negative terminal of the first battery 13 and the second positive terminal of the second battery 14. The first parallel line 24 is connected to the first negative terminal of the first battery 13 and the negative terminal line 22. The second parallel line 25 is connected to the second positive terminal of the second battery 14 and to the side of the changeover switch 40 on the positive terminal line 21 that is closer to the second inverter 34 and the second capacitor 38. The series relay Rs is provided on the series line 23. The first parallel relay Rp1 is provided on the first parallel line 24. The second parallel relay Rp2 is provided on the second parallel line 25.

[0015] The motor 30 is configured as a three-phase AC motor, and includes a rotor in which permanent magnets are embedded in the rotor core, and a stator in which three-phase (U-phase, V-phase, W-phase) coils (three-phase open windings) are wound around the stator core. The rotor is connected to a drive shaft that is connected to a drive wheel via a differential gear.

[0016] The first inverter 32 is connected to the positive electrode side line 21 and the negative electrode side line 22, and is also connected to one end side of the three-phase coils of the motor 30. The second inverter 34 is connected to the side farther from the first and second batteries 13, 14 than the first inverter 32 on the positive electrode side line 21 and the negative electrode side line 22, and is connected to the other end side of the three-phase coils of the motor 30.

[0017] The first and second inverters 32, 34 each include six transistors T11 to T16, T21 to T26 as a plurality of switching elements, and six diodes D11 to D16, D21 to D26 connected in parallel to the six transistors T11 to T16, T21 to T26, respectively. As the transistors T11 to T16, T21 to T26, for example, MOSFETs, IGBTs, etc. are used. The transistors T11 to T16, T21 to T26 are arranged in pairs of two so as to be the source side and the sink side with respect to the positive electrode side line 21 and the negative electrode side line 22. Each of the connection points of the two transistors that form a pair of the transistors T11 to T16 is connected to each of one end sides of the three-phase coils of the motor 30. Each of the connection points of the two transistors that form a pair of the transistors T21 to T26 is connected to each of the other end sides of the three-phase coils of the motor 30.

[0018] The first capacitor 36 is connected near the first inverter 32 on the positive electrode side line 21 and the negative electrode side line 22. The second capacitor 38 is connected near the second inverter 34 on the positive electrode side line 21 and the negative electrode side line 22. In the embodiment, the battery system 11, the first capacitor 36, the first inverter 32, the second inverter 34, and the second capacitor 38 are connected in this order to the positive electrode side line 21 and the negative electrode side line 22 from the left side of FIG. 1. The changeover switch 40 is provided between the first and second inverters 32 and 34 on the positive electrode side line 21. As the changeover switch 40, for example, a semiconductor switch, an insulated switch, or the like is used.

[0019] The system main relay SMR includes a positive electrode side relay SMRB and a negative electrode side relay SMRG. The positive electrode side relay SMRB is provided between the connection point of the positive electrode side line 21 with the first positive electrode side terminal of the first battery 13 and the connection point with the first capacitor 36. The negative electrode side relay SMRG is provided between the connection point of the negative electrode side line 22 with the first parallel line 24 and the connection point with the first capacitor 36.

[0020] The ECU50 is a microcomputer equipped with a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, as well as various drive circuits and various logic ICs. Signals from various sensors are input to the ECU50. For example, the ECU50 receives the voltage Vb1 of the first battery 13 from the voltage sensor 13v, the temperature Tb1 of the first battery 13 from the temperature sensor 13t, the voltage Vb2 of the second battery 14 from the voltage sensor 14v, and the temperature Tb2 of the second battery 14 from the temperature sensor 14t. The ECU50 also receives the current IL1 of the positive side line 21 from the current sensor 21i and the current IL2 of the second parallel line 25 from the current sensor 25i. The ECU50 also receives the rotational position θm of the rotor of the motor 30 from the rotational position sensor 30a, and the phase currents Iu, Iv, and Iw of each phase of the motor 30 from the current sensors 30u, 30v, and 30w. ECU50 also receives the voltage VH from the first capacitor 36 via the voltage sensor 36V, and the voltage VL from the second capacitor 38 via the voltage sensor 38V. ECU50 also receives the on / off signal from the power switch, the shift position SP which is the operating position of the shift lever from the shift position sensor, the accelerator opening Acc which is the amount the accelerator pedal is pressed from the accelerator pedal position sensor, the brake pedal position BP which is the amount the brake pedal is pressed from the brake pedal position sensor, and the vehicle speed V from the vehicle speed sensor.

[0021] Various control signals are output from ECU50. For example, ECU50 outputs control signals to transistors T11~T16, T21~T26 of the first and second inverters 32 and 34, series relay Rs, first and second parallel relays Rp1 and Rp2, changeover switch 40, positive side relay SMRB, and negative side relay SMRG.

[0022] The ECU50 calculates the charge storage ratios SOC1 and SOC2 of the first and second batteries 13 and 14 based on the states of the series relay Rs, the first and second parallel relays Rp1 and Rp2, the positive-side relay SMRB, and the negative-side relay SMRG, as well as the current IL1 of the positive-side line 21 and the current IL2 of the second parallel line 25. When the series relay Rs is ON and the first and second parallel relays Rp1 and Rp2 are OFF, the current IL1 of the positive-side line 21 is equal to the current of the first and second batteries 13 and 14. Also, when the series relay Rs is OFF and the first parallel relay Rp1 is ON, the current IL1 of the positive-side line 21 is equal to the current of the first battery 13. Furthermore, when the series relay Rs is off and the second parallel relay Rp2 is on, the current IL2 in the second parallel line 25 is equal to the current in the second battery 14. The ECU 50 calculates the electrical angle θe and rotational speed Nm of the motor 30 based on the rotational position θm of the motor 30's rotor.

[0023] In the electric vehicle 10 of this embodiment, the ECU 50 basically connects the first and second batteries 13 and 14 in series by turning on the series relay Rs and turning off the first and second parallel relays Rp1 and Rp2. It also turns on the positive side relay SMRB, the negative side relay SMRG, and the changeover switch 40. Then, it sets the required torque Td* required for driving based on the accelerator opening Acc and the vehicle speed V, sets the torque command Tm* for the motor 30 to drive according to the set required torque Td*, and controls the first and second inverters 32 and 34 based on the set torque command Tm*. In controlling the first and second inverters 32 and 34, the first and second inverters 32 and 34 are controlled by pulse width modulation control (PWM control) or square wave control so that the motor 30 is driven according to the torque command Tm*. This type of control is called "normal driving control". Figure 2 is an explanatory diagram showing how voltage is applied to the first and second inverters 32 and 34 during normal driving control. During normal operation control, as shown by the thick solid lines in Figure 2, the voltage from the series connection of the first and second batteries 13 and 14 is applied to the first and second inverters 32 and 34. In this way, the vehicle runs using power from the first and second batteries 13 and 14.

[0024] Next, the operation of the electric vehicle 10 of the embodiment will be described, in particular, when an open circuit abnormality occurs in the series relay Rs during the execution of normal driving control. Figure 3 is a flowchart showing an example of a processing routine executed by the ECU 50. This routine is executed when an open circuit abnormality occurs in the series relay Rs during the execution of normal driving control.

[0025] When this routine is executed, the ECU 50 first determines whether the charge level SOC1 of the first battery 13 is greater than or equal to the threshold Sref1 (step S100). Here, the threshold Sref1 is the threshold used to determine whether the first escape driving control described later can be performed.

[0026] In step S100, when it is determined that the charge level SOC1 of the first battery 13 is equal to or greater than the threshold Sref1, it is determined that the first retraction run control can be executed and is started (step S120), and this routine ends. In the first retraction run control, the first parallel relay Rp1 is turned ON, and the first and second inverters 32 and 34 are controlled to run (retract) using only the power from the first battery 13 of the first and second batteries 13 and 14. Figure 4 is an explanatory diagram showing how voltage is applied to the first and second inverters 32 and 34 during the first retraction run control. During the first retraction run control, the voltage of the first battery 13 is applied to the first and second inverters 32 and 34 as shown by the thick solid line in Figure 4. In this way, retraction run can be performed using only the power from the first battery 13.

[0027] If it is determined in step S100 that the charge level SOC1 of the first battery 13 is less than the threshold Sref1, it is determined that the first evacuation control cannot be performed, and it is determined whether the charge level SOC2 of the second battery 14 is greater than or equal to the threshold Sref2 (step S110). Here, the threshold Sref2 is the threshold used to determine whether the second evacuation control described later can be performed.

[0028] In step S110, when it is determined that the charge level SOC2 of the second battery 14 is equal to or greater than the threshold Sref2, it is determined that the second retraction run control can be executed and is started (step S130), and this routine ends. In the second retraction run control, the second parallel relay Rp2 is turned ON, and the first and second inverters 32 and 34 are controlled to run (retract) using only the power from the second battery 14 of the first and second batteries 13 and 14. Figure 5 is an explanatory diagram showing how voltage is applied to the first and second inverters 32 and 34 during the second retraction run control. During the second retraction run control, the voltage of the second battery 14 is applied to the first and second inverters 32 and 34 as shown by the thick solid line in Figure 5. In this way, retraction run can be performed using only the power from the second battery 14.

[0029] If it is determined in step S110 that the charge level SOC2 of the second battery 14 is less than the threshold Sref2, it is determined that neither the first nor the second retraction control is executable, and retraction is disabled (step S140), and this routine is terminated.

[0030] In the electric vehicle 10 of the embodiment described above, when an open circuit abnormality occurs in the series relay Rs, if the charge level SOC1 of the first battery 13 is equal to or greater than the threshold Sref1, the ECU 50 controls the first and second inverters 32 and 34 as a first escape driving control by turning on the first parallel relay Rp1 and driving using the power from the first battery 13. Furthermore, when an open circuit abnormality occurs in the series relay Rs, if the charge level SOC1 of the first battery 13 is less than the threshold Sref1 and the charge level SOC2 of the second battery 14 is equal to or greater than the threshold Sref2, the ECU 50 controls the first and second inverters 32 and 34 as a second escape driving control by turning on the second parallel relay Rp2 and driving using the power from the second battery 14. Through this control, escape driving can be performed when an open circuit abnormality occurs in the series relay Rs.

[0031] In the above-described embodiment, when an open circuit abnormality occurs in the series relay Rs, if the charge level SOC1 of the first battery 13 is equal to or greater than the threshold Sref1, the first escape driving control is executed, and if the charge level SOC1 of the first battery 13 is less than the threshold Sref1 and the charge level SOC2 of the second battery 14 is equal to or greater than the threshold Sref2, the second escape driving control is executed. However, the embodiment is not limited to this. For example, when an open circuit abnormality occurs in the series relay Rs, regardless of the charge level SOC1 of the first battery 13, if the charge level SOC2 of the second battery 14 is equal to or greater than the threshold Sref2, the second escape driving control may be executed, and if the charge level SOC2 of the second battery 14 is less than the threshold Sref2 and the charge level SOC1 of the first battery 13 is equal to or greater than the threshold Sref1, the first escape driving control may be executed.

[0032] In the embodiment described above, the positive side relay SMRB is kept in the ON state when the second retraction travel control is executed, but the positive side relay SMRB may also be kept in the OFF state.

[0033] 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 will be explained. In this embodiment, the first battery 13 corresponds to the "first battery," the second battery 14 corresponds to the "second battery," the series line 23 corresponds to the "series line," the first parallel line 24 corresponds to the "first parallel line," the second parallel line 25 corresponds to the "second parallel line," and the battery system 11 corresponds to the "battery system." The motor 30 corresponds to the "motor," the first inverter 32 corresponds to the "first inverter," the second inverter 34 corresponds to the "second inverter," and the ECU 50 corresponds to the "control device."

[0034] 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.

[0035] The above describes the forms for implementing this disclosure using embodiments, but 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. [Industrial applicability]

[0036] This disclosure can be used in industries such as electric vehicle manufacturing. [Explanation of symbols]

[0037] 10 Electric vehicle, 11 Battery system, 13 First battery, 13t, 14t Temperature sensor, 13v, 14v, 36v, 38v Voltage sensor, 14 Second battery, 21 Positive side line, 21i, 25i, 30u, 30v, 30w Current sensor, 22 Negative side line, 23 Series line, 24 First parallel line, 25 Second parallel line, 30 Motor, 30a Rotation position sensor, 32 First inverter, 34 Second inverter, 36 First capacitor, 38 Second capacitor, 40 Changeover switch, 50 ECU, D11~D16, D21~D26 Diodes, Rp1 First parallel relay, Rp2 Second parallel relay, Rs Series relay, T11~T16, T21~T26 Transistors.

Claims

1. A battery system comprising: a first battery having a first positive terminal connected to a positive terminal line and a first negative terminal; a second battery having a second positive terminal and a second negative terminal connected to a negative terminal line; a series line connected to the first negative terminal and the second positive terminal; a first parallel line connected to the first negative terminal and the negative terminal line; a second parallel line connected to the second positive terminal and the positive terminal line; a series relay provided on the series line; a first parallel relay provided on the first parallel line; and a second parallel relay provided on the second parallel line. A motor for traction having a three-phase open winding, A first inverter connected to the positive electrode line and the negative electrode line and connected to one end of the three-phase open winding, A second inverter connected to the positive electrode line and the negative electrode line and connected to the other end of the three-phase open winding, A control device that controls the series relay, the first and second parallel relays, and the first and second inverters, An electric vehicle equipped with, If an open circuit abnormality occurs in the series relay while the control device is performing normal driving control, which controls the first and second inverters to run using power from the first and second batteries with the series relay in the ON state, the control device performs retraction driving control, which controls the first and second inverters to run using power from one of the first and second batteries, provided that the charge level is above a threshold, with one of the first and second parallel relays in the ON state. Electric car.

2. The electric vehicle according to claim 1, The control device, as the retraction travel control, If the charge level of the first battery is equal to or greater than a first threshold, a first retraction control is executed, which controls the first and second inverters to turn on the first parallel relay and run using the power from the first battery. If the charge level of the first battery is less than the first threshold and the charge level of the second battery is equal to or greater than the second threshold, a second retraction control is performed, which controls the first and second inverters to turn on the second parallel relay and run using power from the second battery. Electric car.

3. The electric vehicle according to claim 2, The battery system further includes a positive-side relay provided between the first battery and the first and second inverters in the positive-side line. When the control device performs the second retraction travel control, it turns off the positive side relay. Electric car.

Images