Vehicle and deterioration diagnostic procedures for an energy storage device

Abstract

Vehicle comprising: an internal combustion engine (10), an energy storage device (70), a rotary electric machine (20) for receiving an energy input from the energy storage device (70) and for starting the internal combustion engine (10), a sensing unit (156, 158, 160) for sensing the state of the energy storage device (70), and a control unit (200) for performing a deterioration diagnostic process to diagnose, based on the state of the energy storage device (70), whether the energy storage device (70) has deteriorated or not, when a prescribed condition is met, wherein the control unit (200) is configured in such a way as to suppress starting the internal combustion engine (10) when a condition for starting the internal combustion engine (10) is met.after the prescribed condition for carrying out the deterioration diagnosis process has been met and before the deterioration diagnosis process has been completed.

Description

field of technology The present invention relates to a deterioration diagnosis of an energy storage device which is attached to a vehicle. State of the art A hybrid vehicle is known which includes an internal combustion engine, a drive motor, and an energy storage device for supplying energy to the drive motor. In such a vehicle, it is necessary to diagnose with high accuracy whether the energy storage device has deteriorated or not. Document JP 2000 - 131 404 A discloses a deterioration-degree detection device for diagnosing, based on the amount of discharge from a fully charged state to a prescribed discharge voltage value, whether an energy storage device has deteriorated or not. Document US 2004 / 0267417A1 addresses the problem that, if the battery deteriorates, it may not be able to maintain a sufficient voltage for the starter motor of an internal combustion engine. To resolve this issue, the system activation requirement is first addressed in one step, followed by a battery deterioration assessment in a subsequent step. Summary of the invention Technical problem However, if the internal combustion engine starts during a deterioration diagnosis of the energy storage device, the voltage of the energy storage device fluctuates, and the amount of discharge cannot be calculated with high accuracy. It may therefore be impossible to accurately diagnose whether the energy storage device has deteriorated or not. Consequently, in some cases, an opportunity to perform a deterioration diagnosis with high accuracy cannot be sufficiently guaranteed. The deterioration detection device disclosed in the publication described above does not take such a problem into account at all, and therefore it cannot be solved. The present invention was made to solve the problem described above, and one object of the present invention is to provide a vehicle and a deterioration diagnostic method for an energy storage device so that it can be determined with high accuracy whether the energy storage device has deteriorated or not. Solution to the problem A vehicle according to one aspect of the present invention includes: an internal combustion engine, an energy storage device, a rotary electric machine for receiving energy input from the energy storage device and for starting the internal combustion engine, a sensing unit for detecting the state of the energy storage device, and a control unit for performing a deterioration diagnostic process to diagnose, based on the state of the energy storage device, whether the energy storage device has deteriorated or not, given a prescribed condition. The control unit prevents the internal combustion engine from starting if a condition for starting the internal combustion engine is met before the deterioration diagnostic process is complete. The control unit preferably prevents the engine from starting with internal combustion until the deterioration diagnosis process is complete. The control unit also preferably delays the starting of the internal combustion engine until the deterioration diagnosis process is complete. The control unit preferably also releases or removes a suppression of the internal combustion engine starting process when the deterioration diagnosis process is complete. If the prescribed condition is met, the control unit preferably diagnoses, based on one of the amounts of charge and discharge of the energy storage device, whether the energy storage device has deteriorated or not, when a voltage of the energy storage device is changed from a diagnostic start voltage to a diagnostic end voltage. The control unit also preferably suppresses the starting of the engine with internal combustion while the voltage of the energy storage device is changed from the diagnostic start voltage to the diagnostic end voltage. The control unit preferably suppresses the starting of the engine with internal combustion while the voltage of the energy storage device is changed from a prescribed voltage between the diagnostic start voltage and the diagnostic end voltage to the diagnostic end voltage. Furthermore, the vehicle preferably includes an energy conversion device for converting energy from the energy storage device into energy that is supplied to the rotary electric machine. The control unit prevents the internal combustion engine from starting by controlling the energy conversion device to interrupt the energy supply to the rotary electric machine. A deterioration diagnostic method for an energy storage device according to a further aspect of the present invention is a deterioration diagnostic method for an energy storage device used in a vehicle which includes an internal combustion engine, an energy storage device and a rotary electric machine for receiving an energy input from the energy storage device and for starting the internal combustion engine.The deterioration diagnosis procedure includes the following steps: detecting the state of the energy storage device, performing a deterioration diagnosis process to diagnose, based on the state of the energy storage device, whether the energy storage device has deteriorated or not, if a prescribed condition is met, and suppressing the starting of the internal combustion engine until the deterioration diagnosis process is complete. Advantageous effects of the invention According to the present invention, starting the internal combustion engine is suppressed until the deterioration diagnostic process for the energy storage device is complete. Therefore, voltage fluctuations in the energy storage device caused by starting the internal combustion engine are suppressed. Because these voltage fluctuations are suppressed, the total discharge can be calculated with high accuracy during the execution of the deterioration diagnostic process. Consequently, it can be precisely diagnosed whether the energy storage device has deteriorated or not. Furthermore, since starting the internal combustion engine is suppressed, an opportunity to perform a deterioration diagnosis with high accuracy is ensured.Therefore, a vehicle and a deterioration diagnostic procedure for an energy storage device can be provided to determine with high accuracy whether the energy storage device has deteriorated or not. Brief description of the drawings Fig. 1 is an overview block diagram of a vehicle according to a first embodiment. Fig. 2 is a functional block diagram of an ECU mounted on the vehicle according to the first embodiment. Fig. 3 is a graph describing a deterioration diagnostic procedure for an energy storage device based on a relationship between an OCV and a total discharge. Fig. 4 is a flowchart showing a control structure of a program executed by the ECU mounted on the vehicle according to the first embodiment. Fig. 5 is a timing diagram showing the operation of the ECU mounted on the vehicle according to the first embodiment. Fig. 6 is a functional block diagram of an ECU mounted in a vehicle according to a second embodiment.Figure 7 is a flowchart which shows a control structure of a program which is executed by the ECU which is attached to the vehicle according to the second embodiment. Description of the embodiments Embodiments of the present invention are described below with reference to the drawings. In the following description, the same components are designated by the same symbols. Their names and functions are also the same. Accordingly, a detailed description of these will not be repeated. <Erste Ausführungsform> With reference to Fig. 1, a block diagram of a vehicle 1 according to the present embodiment will be described. The vehicle 1 includes a motor 10, a drive shaft 16, a first motor generator (hereinafter referred to as the first MG) 20, a second motor generator (hereinafter referred to as the second MG) 30, a power distribution device 40, a speed reducer 58, a PCU (power control unit) 60, a battery 70, a charging device 78, drive wheels 80, a start switch 150, and an ECU (electronic control unit) 200. Vehicle 1 moves with the driving force supplied by at least one of the motors, motor 10 and the second MG 30. The kinetic energy generated by motor 10 is distributed via the energy distribution device 40 to two paths. One of these two paths is for transmission via the speed reducer 58 to the drive wheels 80, and the other is for transmission to the first MG 20. The first MG 20 and the second MG 30, for example, are three-phase AC rotary electric machines. The first MG 20 and the second MG 30 are driven by the PCU 60. The first MG 20 functions as a generator, producing energy to charge the battery 70 via the PCU 60 by utilizing the kinetic energy of the motor 10, which is divided by the energy distribution device 40. Additionally, the first MG 20, drawing energy from the battery 70, rotates a crankshaft of the motor 10, which serves as an output shaft. Thus, the first MG 20 functions as a starter, starting the motor 10. The second MG 30 functions as a drive motor, which, using at least one of the energy sources stored in battery 70 and energy generated by the first MG 20, provides driving force for the drive wheels 80. The second MG 30 also functions as a generator for charging battery 70 via the PCU 60 using energy generated by regenerative braking. Engine 10, for example, is an internal combustion engine, such as a gasoline engine or a diesel engine. Engine 10 includes a plurality of cylinders 102 and a fuel injection device 104 that supplies fuel to each of the plurality of cylinders 102. Based on a control signal S1 from the ECU 200, the fuel injection device 104 injects an appropriate amount of fuel for each cylinder with appropriate timing and then stops injecting fuel for each cylinder. To detect the rotational speed or speed of the crankshaft of engine 10 (hereinafter referred to as engine rotational speed) Ne, engine 10 is also equipped with an engine rotational speed sensor 11. The engine rotational speed sensor 11 transmits a signal indicating the detected engine rotational speed Ne to the ECU 200. The energy distribution device 40 mechanically couples three elements for rotating the drive wheels 80: the drive shaft 16, the output shaft of the motor 10, and a rotational shaft of the first machine gun 20. The energy distribution device 40 uses each of the three elements mentioned above as a reaction force element, thereby allowing the transfer of kinetic energy between the other two elements. A rotational shaft of the second machine gun 30 is coupled to the drive shaft 16. The energy distribution device 40 is a planetary gear mechanism comprising a sun gear 50, pinion gears 52, a carrier 54, and a ring gear 56. A pinion gear 52 engages with each of the sun gear 50 and ring gear 56. The carrier 54 supports the pinion gears 52 in such a way that it allows them to rotate and is coupled to a crankshaft of the motor 10. The sun gear 50 is coupled to the rotation shaft of the first machine gun 20. The ring gear 56 is coupled via the drive shaft 16 to the rotation shaft of the second machine gun 30 and the speed reducer 58. The speed reducer 58 transfers kinetic energy from the energy distribution device 40 and the second MG 30 to the drive wheels 80. The speed reducer 58 also transfers a reaction force received by the drive wheels 80 from a road surface to the energy distribution device 40 and the second MG 30. The PCU 60 includes a variety of switching elements 62. By controlling the ON / OFF operation of the switching elements 62, the PCU 60 converts DC energy stored in the battery 70 into AC energy to drive the first MG 20 and the second MG 30. The PCU 60 includes a converter and an inverter (both not shown), which are controlled by the ECU 200 based on a control signal S2. The converter amplifies the voltage of DC energy received from the battery 70 and outputs the amplified energy to the inverter. The inverter converts the DC energy output by the converter into AC energy to supply to the first MG 20 and / or the second MG 30. The first MG 20 and / or the second MG 30 are therefore driven using the energy stored in the battery 70.The inverter additionally converts alternating current (AC) energy generated by the first MG 20 and / or the second MG 30 into direct current (DC) energy and supplies it to the converter. The converter reduces the voltage of the DC energy supplied by the inverter and delivers the reduced voltage to battery 70. Battery 70 is thus charged using the energy generated by the first MG 20 and / or the second MG 30. It should be noted that the converter can be omitted. Battery 70 is an energy storage device and a rechargeable DC power supply. In the present embodiment, battery 70 is, for example, a lithium-ion battery. However, battery 70 is not limited to a lithium-ion battery and can, for example, be any type of battery that can degrade. Battery 70 can, for example, be a secondary battery, such as a nickel-metal hydride battery or a lead-acid battery. Furthermore, battery 70 is not limited to being a secondary battery and can, for example, be anything that can generate a DC voltage, such as a capacitor, a solar cell, or a fuel cell. Battery 70 has a voltage on the order of, for example, 200 V. Battery 70 can be charged, in contrast to using the energy generated by the first MG 20 and / or the second MG 30 as described above, by using energy supplied from an external power source (not shown). The battery 70 is equipped with a battery temperature sensor 156 for detecting a battery temperature TB of the battery 70, a current sensor 158 for detecting a current IB of the battery 70 and a voltage sensor 160 for detecting a voltage VB of the battery 70. The battery temperature sensor 156 transmits a signal indicating the battery temperature TB to the ECU 200. The current sensor 158 transmits a signal indicating the current IB to the ECU 200. The voltage sensor 160 transmits a signal indicating the voltage VB to the ECU 200. A start switch 150, for example, is a pressure switch. The start switch 150 can be one that allows a key to be inserted into a key cylinder and rotated to a prescribed position. The start switch 150 is connected to the ECU 200. In response to operation of the start switch 150 by a driver, the start switch 150 transmits a signal ST to the ECU 200. When ECU 200 detects that a start instruction has been received, for example, if the ST signal has been received while the vehicle 1 system is in a stop state, ECU 200 switches the vehicle 1 system from the stop state to a start state. ECU 200 also detects that a stop instruction has been received if the ST signal has been received while the vehicle 1 system is in the start state, and then switches the vehicle 1 system from the start state to the stop state. In the following descriptions, operation of the start switch 150 by the driver when the vehicle 1 system is in the start state is referred to as an IG OFF operation, and operation of the start switch 150 by the driver when the vehicle 1 system is in the stop state is referred to as an IG ON operation.As soon as the system of vehicle 1 switches to the start state, energy is supplied to a variety of equipment necessary for vehicle 1 to move, and this equipment then enters an operational state. Conversely, as soon as the system of vehicle 1 switches to the stop state, energy is no longer supplied to some of the equipment necessary for vehicle 1 to move, and this equipment then enters a standby operating state. A first rotary encoder 12 is provided on the first MG 20. The first rotary encoder 12 detects the rotational speed or rotational speed Nm 1 of the first MG 20. A second rotary encoder 13 is provided on the second MG 30. The first rotary encoder 12 transmits a signal indicating the detected rotational speed Nm 1 to the ECU 200. The second rotary encoder 13 detects the rotational speed or rotational speed Nm2 of the second MG 30. The second rotary encoder 13 transmits a signal indicating the detected rotational speed Nm2 to the ECU 200. A drive shaft 82 between the speed reducer 58 and the drive wheels 80 is equipped with a wheel speed sensor 14. The wheel speed sensor 14 detects a rotational speed Nw of the drive wheels 80. The wheel speed sensor 14 transmits a signal indicating the detected rotational speed Nw to the ECU 200. The ECU 200 calculates a vehicle speed V based on the received rotational speed Nw. It should be noted that the ECU 200 can also calculate the vehicle speed V based on the rotational speed Nm2 of the second MG 30 instead of the rotational speed Nw. When a charging plug 300 is attached to the vehicle 1, a charging device 78 charges the battery 70 using energy supplied by an external power supply 302. The charging plug 300 is connected to one end of a charging cable 304. The other end of the charging cable 304 is connected to the external power supply 302. A positive electrode terminal of the charging device 78 is connected to a power supply line PL, which connects a positive electrode terminal of the power control unit 60 and a positive electrode terminal of the battery 70. A negative electrode terminal of the charging device 78 is connected to a grounding line NL, which connects a negative electrode terminal of the power control unit 60 and a negative electrode terminal of the battery 70. The ECU 200 generates the control signal S1 to control motor 10 and outputs the generated control signal S1 to motor 10. Furthermore, the ECU 200 generates the control signal S2 to control PCU 60 and outputs the generated control signal S2 to PCU 60. By controlling motor 10, PCU 60 and the like, the ECU 200 controls the entire hybrid system, that is, a state of charging / discharging of the battery 70 and operating states of motor 10, the first MG 20 and the second MG 30, so that the vehicle 1 can move most efficiently. The ECU 200 calculates a requested driving force, which corresponds to the amount of depression of an accelerator pedal (not shown) provided at a driver's seat. The ECU 200 controls a torque of the first MG 20 and the second MG 30 and an output of motor 10 in accordance with the calculated requested driving force. Vehicle 1, which has a device as described above, moves solely with the aid of the second MG 30 if the motor 10 is inefficient at the start of movement or during low-speed movement. Additionally, for example during normal movement, the energy distribution device 40 splits the kinetic energy of the motor 10 into two paths of kinetic energy. Kinetic energy along one path directly drives the drive wheels 80. Kinetic energy along the other path drives the first MG 20 to generate energy. At this time, the ECU 200 uses the generated energy to drive the second MG 30. By driving the second MG 30, assistance is thus provided in driving the drive wheels 80. When vehicle 1 reduces its speed, regenerative braking is performed by the second motor 30, which follows the rotation of the drive wheels 80 and functions as a generator. The energy recovered through regenerative braking is stored in battery 70. It should be noted that when the remaining capacity (hereinafter referred to as SOC (state of charge)) of the energy storage device has decreased and requires charging, the ECU 200 increases the output of motor 10 to increase the amount of energy generated by the first motor 20. This increases the SOC of battery 70.Additionally, the ECU 200 can itself, even while moving at low speed, exercise control to increase the driving power of the motor 10 as required, for example when the battery 70 needs charging as described above, when an auxiliary machine, such as an air conditioner, is to be driven, and when the temperature of the coolant for the motor 10 is to be increased to a prescribed temperature. When controlling the charging and discharging rates of battery 70, the ECU 200, based on a battery temperature TB and the current state of charge (SOC), sets an allowable energy input when charging battery 70 (hereinafter referred to as the "upper charge energy limit Win") and a allowable energy output when discharging battery 70 (hereinafter referred to as the "upper discharge energy limit Wout"). For example, if the SOC current decreases, the upper discharge energy limit Wout is gradually set lower. Conversely, if the SOC current increases, the upper charge energy limit Win is gradually set lower. The secondary battery, used as battery 70, also exhibits a temperature dependency, causing an increase in internal resistance at low temperatures. At high temperatures, it is additionally necessary to prevent an excessive temperature increase caused by further heat generation. It is therefore preferable to reduce both the upper discharge energy limit (Wout) and the upper charge energy limit (Win) when the battery temperature (TB) is low and when the battery temperature (TB) is high. The ECU 200 sets the upper charge energy limit (Win) and the upper discharge energy limit (Wout) according to the battery temperature (TB) and the state of charge (SOC) current, for example, by using a characteristic map or similar method. In vehicle 1, which has the device described above, it is necessary to diagnose with high accuracy whether battery 70 has deteriorated or not. Therefore, when the prescribed conditions are met, ECU 200 performs a deterioration diagnostic process to determine, based on the amount of discharge, whether battery 70 has deteriorated or not. However, if engine 10 starts during the execution of the deterioration diagnostic process for battery 70, the voltage of battery 70 fluctuates, and thus the amount of discharge cannot be calculated with high accuracy in some cases. Therefore, in some cases, it cannot be precisely diagnosed whether battery 70 has deteriorated or not. Accordingly, the present embodiment has a feature in that the ECU 200 suppresses starting the engine 10 if a condition for starting the engine 10 is met before the deterioration diagnosis process for diagnosing whether the battery 70 has deteriorated or not has been completed. Fig. 2 shows a functional block diagram of the ECU 200 installed in the vehicle according to the present embodiment. The ECU 200 includes a deterioration diagnostic process unit 202, a diagnostic determination unit 204, a start suppression unit 206, a termination determination unit 208, and a suppression release unit 210. When there is a request to run the deterioration diagnosis process to diagnose whether battery 70 has deteriorated or not, the deterioration diagnosis process unit 202 runs the deterioration diagnosis process under the condition that the prescribed conditions are met. The case in which a request to perform a deterioration diagnosis exists, for example, in a case where, after the vehicle 1 was manufactured or after battery 70 was replaced with a new battery, a prescribed number of years have elapsed, during which time there is a possibility that battery 70 has deteriorated. Alternatively, the case in which a request to perform a deterioration diagnosis exists, for example, in a case where, after the aforementioned prescribed years have elapsed, a further prescribed period has elapsed without battery 70 being replaced. Alternatively, the case in which a request to perform a deterioration diagnosis exists in a case in which a user or operator of vehicle 1 makes a request. The user or operator can, for example, instruct the vehicle 1 to perform the deterioration diagnosis process by performing a prescribed, special operation of the equipment (such as an accelerator pedal, a brake pedal, or various switches) installed in the vehicle 1, which differs from the normal operation. The user or operator can also instruct the vehicle 1 to perform the deterioration diagnosis process by connecting a prescribed device (e.g., an abnormality diagnostic device) to the vehicle 1 and performing a prescribed operation of that device. In the present embodiment, the prescribed conditions are described as including, for example, a condition that the battery temperature TB is equal to or greater than a threshold TB(0), and a condition that the OCV (open circuit voltage) of the battery 70 is equal to or greater than a threshold OCV(0). The threshold TB(0) is used to determine whether a diagnostic result is affected by voltage fluctuations caused by the internal resistance of battery 70. Therefore, if the battery temperature TB is equal to or greater than the threshold TB(0), the influence of voltage fluctuations caused by the internal resistance of battery 70 on the diagnostic result can be avoided by performing the deterioration diagnostic process. The deterioration diagnostic process unit 202 estimates the OCV of battery 70 based on the voltage VB and the battery temperature TB. The deterioration diagnostic process unit 202 estimates the OCV corresponding to the voltage VB and battery temperature TB as determined, for example, using a characteristic map or the like that shows a relationship between voltage VB, battery temperature TB, and the OCV. In addition to the voltage VB and battery temperature TB, the deterioration diagnostic process unit 202 can estimate the OCV based on, for example, the state of charge (SOC) of battery 70, the degree of deterioration of battery 70, and the like. The threshold OCV(0) is a diagnostic start voltage. A value at which it is possible to ensure a total discharge sufficient to obtain a diagnostic result with sufficient accuracy can be determined as the threshold OCV(0). The total discharge is an integrated value of the amount of discharge (discharge current) when the battery 70 is discharged from the diagnostic start voltage OCV(0) to a diagnostic end voltage OCV(1) at a fixed discharge value. Preferably, the threshold OCV(0) should be a value close to the state of charge (SOC) corresponding to the fully charged state (upper limit) of battery 70. It is also preferably desirable that the diagnostic termination voltage OCV(1) should be a value close to the lower limit of the SOC of battery 70. This improves diagnostic accuracy. The OCV threshold, which is the required condition, can also be a value greater than OCV(0). When a deterioration diagnosis is requested and the prescribed conditions are met, in the present embodiment the deterioration diagnosis process unit 202 causes the battery 70 to be discharged by a fixed amount until the OCV of the battery 70 changes from the diagnostic start voltage OCV(0) to the diagnostic end voltage OCV(1), as shown in Fig. 3, and integrates this amount of discharge (current during discharge). The deterioration diagnosis process unit 202 compares a sum of discharge D(0) from the diagnostic start voltage OCV(0) to the diagnostic end voltage OCV(1) and a sum of discharge D(1) from OCV(0) to OCV(1) when the battery 70 is new, and diagnoses whether the battery 70 has deteriorated or not. Battery 70 can be discharged, for example, using a discharge resistor provided in PCU 60, or using the first MG 20 or the second MG 30, or it can be discharged by operating other electrical equipment connected to battery 70 besides PCU 60. Examples of other electrical equipment connected to battery 70 besides PCU 60 include a DC / DC converter and an air conditioning compressor. The total discharge D(1) when the battery is new can be a prescribed value, which is adjusted through experimentation or the like. If the battery 70 is discharged by a fixed amount from the diagnostic start voltage OCV(0) to the diagnostic end voltage OCV(1) during a prescribed period, a total discharge can be stored in a memory or the like as the total discharge D(1). It should be noted that the prescribed period includes, for example, a period during the manufacturing stage of vehicle 1, a period before transport of vehicle 1, a period before delivery of vehicle 1 to the user, a period from delivery to the user until the expiration of a prescribed usage period, or the like. The deterioration diagnosis process unit 202 can diagnose that battery 70 has deteriorated if, for example, the absolute value of the difference between the sums of discharges D(0) and D(1) is equal to or greater than a threshold. Alternatively, the deterioration diagnosis process unit 202 can diagnose that battery 70 has deteriorated if the ratio of the sum of discharges D(0) to the sum of discharges D(1) is less than or equal to a threshold. Alternatively, the deterioration diagnosis process unit 202 can calculate a degree of deterioration that shows a gradual or continuous change relative to the difference or ratio mentioned above. It should be noted that a value set, for example, as the fixed discharge amount, should not be too low to prevent unnecessarily extending the diagnostic time from start to finish of the deterioration diagnosis. Conversely, a value set as the fixed discharge amount should not be too high to prevent battery 70 deterioration due to the deterioration diagnosis. The fixed discharge amount can be a predefined value or can be determined based on the condition of battery 70, the condition of an auxiliary load, or similar factors when the discharge process begins. If battery 70 is diagnosed as deteriorating, the deterioration diagnostic process unit 202, for example, notifies the driver or operator to prompt battery 70 replacement. The deterioration diagnostic process unit 202 can, for example, cause a prescribed indicator light (not shown) to illuminate, cause a display device to show a message prompting battery 70 replacement, provide a notification of battery 70 replacement by means of a tone or voice, or cause the abnormality diagnostic device connected to the vehicle 1 to display a message prompting battery 70 replacement. The deterioration diagnosis process unit 202 can activate a diagnosis request flag when there is a request to execute the deterioration diagnosis process for battery 70. Furthermore, during the execution of the deterioration diagnosis process for battery 70, that is, during the period from the start to the end of the deterioration diagnosis, the deterioration diagnosis process unit 202 can activate a diagnosis execution flag indicating that the deterioration diagnosis process is in execution. The diagnostic detection unit 204 determines whether or not there is a request to execute the deterioration diagnostic process for battery 70, and whether or not the deterioration diagnostic process for battery 70 is in execution. For example, if both the diagnostic request marker and the diagnostic execution marker are ON, the diagnostic detection unit 204 can determine that there is a request to execute the deterioration diagnostic process and that the deterioration diagnostic process for battery 70 is in execution. The diagnostic detection unit 204 can, for example, turn on a diagnostic detection marker if it determines that there is a request to execute the deterioration diagnostic process and that the deterioration diagnostic process for battery 70 is in execution. When the diagnostic detection unit 204 determines that there is a request to perform the deterioration diagnostic process for battery 70, and that the deterioration diagnostic process for battery 70 is in progress, the start suppression unit 206 prevents the engine 10 from starting until the deterioration diagnostic process for battery 70 is complete. In the present embodiment, the start suppression unit 206 prevents the engine 10 from starting during the period from the start of the battery 70 deterioration diagnosis process until the completion of the deterioration diagnosis process. In other words, even if the condition for starting the engine 10 is met based on a state of the vehicle 1, the start suppression unit 206 does not start the engine 10. For example, the start suppression unit 206 either negates a request to start the engine 10 or delays the execution of the start control based on the request to start the engine 10 until the deterioration diagnosis process is complete. In the present embodiment, the condition for starting the motor 10 is different from a condition that the deterioration diagnosis process is complete, and includes, for example: a condition of IG ON, a condition that there is a request to warm up the motor 10, such as, for example, that a coolant temperature is equal to or below a threshold, a condition that a brake is in the OFF state, such as, for example, that the depressing force on the brake pedal is equal to or less than a threshold, a condition that an energy required for the vehicle 1 exceeds an output of the second MG 30 and must be balanced by an output of the motor 10, and a condition that the battery 70 must be charged using the motor 10 because the SOC falls below a threshold.It should be noted that at least one of the many conditions listed above can only be included as the condition for starting engine 10. The final determination unit 208 determines whether the deterioration diagnostic process for battery 70 has been completed. The final determination unit 208 can determine that the deterioration diagnostic process for battery 70 has been completed when, for example, the OCV has reached (decreased from) the diagnostic final voltage OCV(1). Alternatively, the final determination unit 208 can determine that the deterioration diagnostic process for battery 70 has been completed when, for example, a prescribed time has elapsed after the start of the deterioration diagnostic process for battery 70, during which completion of the deterioration diagnostic process can be reliably determined. The final investigation unit 208 can, for example, activate a final investigation marker when the deterioration diagnosis process for battery 70 has been completed. When the completion determination unit 208 determines that the deterioration diagnostic process for battery 70 has been completed, the suppression release unit 210 releases the suppression of starting engine 10. For example, the suppression release unit 210 can release the suppression of starting engine 10 if the completion determination marker is in the OFF state. After the suppression of starting engine 10 has been released, the start control for engine 10 can be executed by validating the nullified request to start engine 10, or the start control for engine 10 can be executed in response to a request to start engine 10 received after the completion of the deterioration diagnostic process for battery 70. Although the deterioration diagnostic process unit 202, the diagnostic determination unit 204, the start suppression unit 206, the termination determination unit 208, and the suppression release unit 210, shown in Fig. 2, are described in the present embodiment as being implemented by a CPU of the ECU 200 executing a program stored in memory, and are described as functioning as software, they can also be implemented in hardware. It should be noted that such a program is recorded in a storage medium for installation in the vehicle 1. Referring to Fig. 4, a control structure of a program executed by the ECU 200, which is attached to the vehicle 1 according to the present embodiment, is described. In step 100 (referred to as "S" below), the ECU 200 determines whether or not there is a request to execute the deterioration diagnostic process for battery 70, and whether or not the deterioration diagnostic process is in progress. If there is a request to execute the deterioration diagnostic process, and if the deterioration diagnostic process is in progress (YES in S100), the process proceeds to S102. If not (NO in S100), this process terminates. In S102, the ECU 200 prevents the engine 10 from starting. In S104, the ECU 200 determines whether the battery deterioration diagnostic process for battery 70 has been completed. If the battery deterioration diagnostic process for battery 70 has been completed (YES in S104), the process is transferred to S106. If not (NO in S104), the process returns to S104. In S106, the ECU 200 releases the prevention of engine 10 starting. The operation of the ECU 200, which is installed in the vehicle 1 according to the present embodiment, will now be described on the basis of the aforementioned structures and the flowchart with reference to Fig. 5. As shown in Fig. 5, for example, since the deterioration diagnosis process is not executed if there is no request to execute the deterioration diagnosis process (NO in S100), starting the engine 10 is not prevented. Therefore, the engine 10 will be started in response to a request to start the engine 10. On the other hand, since the deterioration diagnosis process is executed when there is a request to execute the deterioration diagnosis process at time T(0) and when the prescribed conditions are met at time T(1) (YES in S100), starting the engine 10 is prevented (S102). When the deterioration diagnosis process is executed, battery 70 is discharged from a state in which its OCV (Optimal Current Value) is equal to or greater than the diagnostic start voltage OCV(0) by a fixed amount of discharge. The deterioration diagnosis process is complete when, at time T(2), the OCV of battery 70 becomes equal to or less than the diagnostic end voltage OCV(1). Based on a result obtained by comparing the sum of the discharges D(0) when battery 70 is discharged until its OCV decreases from the diagnostic start voltage OCV(0) to the diagnostic end voltage OCV(1), with the sum of the discharges D(1) when battery 70 is new, the ECU 200 diagnoses whether battery 70 has deteriorated or not. Since the deterioration diagnosis process for battery 70 continues until time T(2) (NO in S104), the condition preventing engine 10 from starting persists. Therefore, even if there is a request to start engine 10, engine 10 will not start. On the other hand, if the deterioration diagnosis process for battery 70 is completed at time T(2) (YES in S104), a prevention of starting engine 10 is resolved (S106). Therefore, if there is a request to start engine 10, engine 10 is started using the first MG 20. Referring to Fig. 5, the description states that the execution of the deterioration diagnosis process is initiated upon receipt of the request to execute the deterioration diagnosis process. However, if the prescribed conditions are met at the time of receipt of the request to execute the deterioration diagnosis process, the deterioration diagnosis process will be executed from the time of receipt of the request to execute the deterioration diagnosis process. As described above, in the present embodiment of vehicle 1, starting the engine 10 is prevented until the battery deterioration diagnostic process is complete. Since starting the engine 10 is prevented, voltage fluctuations in the battery 70, which would otherwise occur if the engine 10 were to start, are suppressed. Because these voltage fluctuations are suppressed, the total discharge can be calculated with high accuracy during the execution of the battery deterioration diagnostic process. Consequently, it can be precisely diagnosed whether the battery 70 has deteriorated or not. Furthermore, since starting the engine 10 is prevented, an opportunity to perform a deterioration diagnosis with high accuracy is ensured.Therefore, a vehicle and a deterioration diagnostic method for an energy storage device can be provided to determine with high accuracy whether the energy storage device has deteriorated or not. While Fig. 1 shows a vehicle 1 which has the drive wheels 80, for example, as front wheels, the present invention is not limited to such a drive system. For example, the vehicle 1 can have the drive wheels as rear wheels. Furthermore, vehicle 1 is not limited to the type of hybrid vehicle shown in Fig. 1. For example, vehicle 1 can be a vehicle in which the second MG 30 in Fig. 1 is omitted. Alternatively, vehicle 1 can also be a vehicle in which the second MG 30 in Fig. 1 is coupled to a drive shaft for driving the rear wheels, instead of being coupled to the drive shaft 16 of the front wheels. In addition, a shifting mechanism can be provided between the drive shaft 16 and the speed reducer 58 or between the drive shaft 16 and the second MG 30. Furthermore, only the energy storage device can be attached to vehicle 1, and the present invention can be adapted to, for example, a vehicle that uses only the motor 10 as a drive source and to which an auxiliary battery is attached. Furthermore, while the ECU 200 has been described as a single ECU in Fig. 1, two or more ECUs can be used. For example, the operation of the ECU 200 according to Fig. 1 can be divided between an engine ECU for controlling the engine 10 and a hybrid ECU for controlling the PCU 60. Furthermore, in the present embodiment, the start suppression unit 206 has been described as preventing the motor 10 from starting from the time the deterioration diagnosis process begins. However, the start suppression unit 206 can also prevent the motor 10 from starting at a time after the deterioration diagnosis process has started. In other words, the start suppression unit 206 can prevent the motor 10 from starting after the deterioration diagnosis process has begun. The start suppression unit 206 can prevent the engine 10 from starting if the OCV is below a prescribed value OCV(2) ( <OCV(0)) erreicht hat, ehe diese zum Beispiel die Diagnoseabschlussspannung OCV(1) erreicht. Damit kann ein Starten des Motors 10 kurz bevor die OCV der Batterie 70 die Diagnoseabschlussspannung OCV(1) erreicht, verhindert werden. Daher kann eine Abnahme in der Genauigkeit eines Diagnoseergebnisses aufgrund eines temporären Abnehmens bei der OCV auf die Diagnoseabschlussspannung OCV(1) oder niedriger, was durch Spannungsfluktuation auf Grund des Startens des Motors 10 verursacht wird, unterdrückt werden. In the present embodiment, the prescribed conditions have been described as including the condition that the OCV of battery 70 is equal to or higher than the threshold value OCV(0). However, instead of this condition, the prescribed conditions may include a condition that the SOC of battery 70 is equal to or higher than a threshold value SOC(0), or a condition that the voltage VB of battery 70 is equal to or higher than a threshold value VB(0). It should be noted that the threshold values ​​SOC(0) and VB(0) are both values ​​that correspond to OCV(0). Furthermore, if the condition that the OCV of battery 70 is equal to or greater than the threshold OCV(0) is not met, the ECU 200 can perform the deterioration diagnostic process after the engine 10 has been started, and battery 70 will be charged until the OCV of battery 70 becomes equal to or greater than the threshold OCV(0). In the present embodiment, the description further provides that the deterioration diagnosis process unit 202 shown in Fig. 2 diagnoses whether the battery 70 has deteriorated or not based on the result obtained by comparing the sum of the discharge D(0), as a result of discharging the battery 70 at a fixed amount from the diagnostic start voltage OCV(0) to the diagnostic end voltage OCV(1), and the sum of the discharge D(1) when the battery 70 is new. However, the deterioration diagnosis process is not limited to such a process. For example, the deterioration diagnostic process unit 202 can repeat an operation of stopping the discharge at a fixed discharge amount, just before the OCV of battery 70 reaches the diagnostic cut-off voltage OCV(1), and then directly measure the OCV. This allows for a highly accurate determination of whether the OCV of battery 70 has reached the diagnostic cut-off voltage OCV(1). It should be noted that the operation described above can be repeated at prescribed time intervals. Alternatively, the deterioration diagnostic process unit 202 can cause battery 70 to discharge at a fixed rate until the voltage VB changes from the diagnostic start voltage VB(0) to a diagnostic end voltage VB(1). In this case, the deterioration diagnostic process unit 202 calculates a total discharge D(2) from the diagnostic start voltage VB(0) to the diagnostic end voltage VB(1). Based on a result obtained by comparing a calculated total discharge D(2) with a total discharge D(3) when the battery is new, the deterioration diagnostic process unit 202 diagnoses whether battery 70 has deteriorated or not. The total discharge D(3) is the total discharge until the voltage VB changes from the diagnostic start voltage VB(0) to the diagnostic end voltage VB(1) when the battery 70 is new. Alternatively, the deterioration diagnostic process unit 202 can calculate a total charge C(0) by charging battery 70 at a fixed charge level from a diagnostic start voltage OCV(3) to a diagnostic end voltage OCV(4) (>OCV(3)) and by integrating a charging current. Based on a result obtained by comparing the calculated total charge C(0) with the total charge C(1) when battery 70 is new, the deterioration diagnostic process unit 202 can diagnose whether battery 70 has deteriorated or not. Charging at a fixed charge level is implemented, for example, by charging via an external power supply 302. In this case, instead of the condition that the OCV of battery 70 is equal to or greater than a threshold OCV(0), the prescribed conditions include a condition that the OCV of battery 70 is equal to or less than the threshold OCV(3). The threshold OCV(3) is a diagnostic start voltage. A value that ensures a charging current sufficient to obtain a diagnostic result with adequate accuracy can be determined as the threshold OCV(3). The charging current is an integral value of the charging magnitude (charging current) when the battery is charged from the diagnostic start voltage OCV(3) to the diagnostic end voltage OCV(4) at a fixed charging rate. Preferably, the threshold OCV(3) should be a value close to the state of charge (SOC) corresponding to the lower limit of the SOC of battery 70. Preferably, the diagnostic termination voltage OCV(4) should be a value close to the SOC corresponding to the fully charged state (upper limit) of battery 70. This will improve diagnostic accuracy. The OCV threshold, which is the required condition, can also be a value lower than OCV(3). The diagnostic start voltage and the diagnostic end voltage can also be a value of the voltage VB instead of the OCV. Instead of requiring that the OCV of battery 70 be equal to or lower than the threshold OCV(3), the prescribed conditions for performing the deterioration diagnosis process by charging at a fixed charge amount may include a condition that the SOC of battery 70 be equal to or lower than the threshold SOC(1), or a condition that the voltage VB of battery 70 be equal to or lower than the threshold VB(1). It should be noted that the thresholds SOC(1) and VB(1) are both values ​​that correspond to OCV(3). Furthermore, the prescribed conditions for executing the deterioration diagnosis process by charging at a fixed charge level or by discharging at a fixed discharge level may include a condition that motor 10 is in a stop state. Whether motor 10 is in a stop state or not can be determined based on a state of motor 10 (e.g., if the motor rotation speed Ne is less than a threshold Ne(0), or similar) and a state of the motor 10 control system (e.g., an IG OFF state, a helper selection state where the control signal S2 is not output, or similar). Furthermore, the prescribed conditions for performing the deterioration diagnosis process by charging at a fixed amount of charge or by unloading at a fixed amount of charge may include a condition that vehicle 1 is in a stop state. Alternatively, the prescribed conditions may include a condition that vehicle 1 is in a moving state. Whether vehicle 1 is in a stop state or a moving state can be determined based on the vehicle speed V, the rotational speed Nw of the drive wheels 80, or the rotational speed Nm2 of the second MG 30. The ECU 200 can determine that vehicle 1 is in a stop state if, for example, the vehicle speed V is less than a threshold value.Alternatively, the ECU 200 can determine that vehicle 1 is in a moving state if the vehicle speed V is greater than the threshold. <Zweite Ausführungsform> A vehicle according to a second embodiment is described below. The vehicle according to the second embodiment differs from the configuration of vehicle 1 according to the first embodiment described above with regard to the operation of the ECU 200. The remaining configuration is identical to that of vehicle 1 according to the first embodiment described above. These are designated by the same reference numerals. Their functions are also identical. Accordingly, a detailed description of them will not be repeated here. The present embodiment has a feature in that the ECU 200 switches off a gate of the PCU 60 during the execution of the deterioration diagnosis process to diagnose whether the battery 70 has deteriorated or not. Fig. 6 shows a functional block diagram of the ECU 200, which is fitted to the vehicle according to the present embodiment. The functional block diagram of the ECU 200 shown in Fig. 6 differs from the functional block diagram of the ECU 200 shown in Fig. 2 of the first embodiment in that a gate shutdown unit 306 is included instead of the start suppression unit 206, and in that a shutdown release unit 310 is included instead of the suppression release unit 210. The remaining arrangement is the same as in the functional block diagram of the ECU 200 shown in Fig. 2. Accordingly, a detailed description of it will not be repeated. When the diagnostic detection unit 204 determines that there is a request to execute the deterioration diagnostic process for battery 70, and that the deterioration diagnostic process for battery 70 is in progress, the gate shutdown unit 306 switches off the gate of the PCU 60. The gate shutdown unit 306 switches off the gate of the PCU 60 by deactivating all switching elements of the plurality of switching elements 62 provided in the PCU 60. By switching off the gate of the PCU 60, the first MG 20 enters a non-operating state. Therefore, even if there is a request to start the engine 10 based on a state of the vehicle 1, the engine 10 cannot be started. In the present embodiment, the gate shutdown unit 306 is configured to shut down the gate of the PCU 60 from the start until the completion of the deterioration diagnostic process for the battery 60. However, the gate shutdown unit 306 can also shut down the gate of the PCU 60 after the start of the deterioration diagnostic process for the battery 70. When the final determination unit 208 determines that the deterioration diagnostic process for battery 70 has been completed, the shutdown release unit 310 triggers the shutdown of the PCU 60 gate. The shutdown release unit 310 can trigger the shutdown of the PCU 60 gate if, for example, the final determination marker is in the OFF state. After the shutdown of the PCU 60 gate is triggered, the first MG 20 enters an operating state. Therefore, the start control for motor 10 is executed in response to a request to start motor 10. Although the deterioration diagnostic process unit 202, the diagnostic determination unit 204, the gate shutdown unit 306, the termination determination unit 208, and the shutdown release unit 310, which are shown in Fig. 6, are described in the present embodiment as being implemented by a CPU of the ECU 200 by executing a program stored in memory, and thus functioning as software, they can also be implemented in hardware. It should be noted that such a program is included in a storage medium for installation in vehicle 1. Referring to Fig. 7, a control structure of a program executed by the ECU 200, which is attached to a vehicle 1 according to the present embodiment, is described. In the flowchart shown in Fig. 7, the same processes are assigned the same step numbers as those in the flowchart shown above in Fig. 4. The processing of these processes is also identical. Therefore, a detailed description of this process will not be repeated here. If there is a request to execute the deterioration diagnostic process for battery 70, and if the deterioration diagnostic process is in execution (YES in S100), the ECU 200 switches off the gate of the PCU 60 by switching off the multitude of switching elements 62 in S200. Furthermore, if the deterioration diagnosis process for battery 70 has been completed (YES in S104), the ECU200 triggers the shutdown of the gate of the PCU 60 in S202. The operation of the ECU 200, which is installed in the vehicle 1 according to the present embodiment, will now be described based on the preceding structures and flowcharts. Since the deterioration diagnostic process is not executed if, for example, there is no request to execute the deterioration diagnostic process (NO in S100), the gate of PCU 60 is not switched off. Therefore, motor 10 is started in response to a request to start motor 10. Since the deterioration diagnosis process is executed when there is a request to execute the deterioration diagnosis process, and when the prescribed conditions are met (YES in S100), the gate of PCU 60 is switched off (S200). When the deterioration diagnostic process is executed, battery 70 is discharged to a fixed amount from a state where the OCV of battery 70 is equal to or greater than the diagnostic start voltage OCV(0). The deterioration diagnostic process is complete when the OCV of battery 70 becomes equal to or less than the diagnostic end voltage OCV(1). ECU 200 diagnoses whether battery 70 has deteriorated based on a result obtained by comparing the sum of the discharges D(0) when battery 70 is discharged until the OCV decreases from the diagnostic start voltage OCV(0) to the diagnostic end voltage OCV(1), and the sum of the discharges D(1) when battery 70 is new. While the deterioration diagnostic process for battery 70 continues (NO in S104), the shutdown of the PCU 60 gate also continues. Even if there is a request to start motor 10, motor 10 will therefore not start because the first MG 20 is in the non-operational state. When the deterioration diagnostic process for battery 70 is complete (YES in S104), the shutdown of the PCU 60 gate is resolved (S202). The first MG 20 therefore enters the operating state. Consequently, when there is a request to start motor 10, motor 10 is started using the first MG 20. As described above, in the present embodiment of vehicle 1, the gate of the PCU 60 remains switched off until the deterioration diagnosis process for battery 70 is complete. As a result of the PCU 60 gate being switched off, the motor 10 enters a non-startable state. Since the motor 10 cannot be started, voltage fluctuations in battery 70 that would occur if the motor 10 were to start are suppressed. Because the voltage fluctuations in battery 70 are suppressed, the total discharge can be calculated with high accuracy during the execution of the deterioration diagnosis process. Consequently, it can be precisely diagnosed whether or not battery 70 has deteriorated. Furthermore, since starting the motor 10 is prevented, an opportunity to perform the deterioration diagnosis with high accuracy is ensured.Therefore, a vehicle and a deterioration diagnostic procedure can be provided to determine with high accuracy whether an energy storage device has deteriorated or not. It is understood that the embodiments disclosed herein are in every respect illustrative and not limiting. The scope of protection of the present invention is defined by the terms of the claims and not so much by those of the description above, and is to be understood as including any modifications within the scope and meaning that are equivalent to or comparable with the terms of the claims. An ECU thus executes a program which includes the steps: preventing an engine from starting (S102) when there is a request to perform a deterioration diagnostic process, and when the deterioration diagnostic process is in progress (YES in S100), and resolving a prevention of engine starting (S106) when the deterioration diagnostic process is complete (YES in S104). Reference symbol list 1 Vehicle; 10 Engine; 11 Engine Rotation Speed ​​Sensor; 12 First Rotation Indicator; 13 Second Rotation Indicator; 14 Wheel Speed ​​Sensor; 16 Drive Shaft; 20 First Machine Gear; 30 Second Machine Gear; 40 Power Distribution Device; 50 Sun Gear; 52 Pinion Gear; 54 Carrier; 56 Ring Gear; 58 Speed ​​Reducer; 60 PCU; 62 Switching Element; 70 Battery; 78 Charging Device; 80 Drive Wheel; 82 Drive Shaft; 102 Cylinder; 104 Fuel Injection Device; 150 Start Switch; 156 Battery Temperature Sensor; 158 Current Sensor; 160 Voltage Sensor; 200 ECU; 202 Deterioration Diagnostic Process Unit; 204 Diagnostic Determination Unit; 206 Start Suppression Unit; 208 End Determination Unit; 210 Suppression Release Unit; 300 Charging plug; 302 External power supply; 304 Charging cable; 306 Gate shutdown unit; 310 Shutdown release unit

Claims

Vehicle comprising: an internal combustion engine (10), an energy storage device (70), a rotary electric machine (20) for receiving an energy input from the energy storage device (70) and for starting the internal combustion engine (10), a sensing unit (156, 158, 160) for sensing the state of the energy storage device (70), and a control unit (200) for performing a deterioration diagnostic process to diagnose, based on the state of the energy storage device (70), whether the energy storage device (70) has deteriorated or not, when a prescribed condition is met, wherein the control unit (200) is configured in such a way as to suppress the starting of the internal combustion engine (10) when a condition for starting the internal combustion engine (10) is met.after the prescribed condition for carrying out the deterioration diagnosis process has been met and before the deterioration diagnosis process has been completed. Vehicle according to claim 1, wherein the control unit (200) prevents the internal combustion engine (10) from starting until the deterioration diagnosis process is completed. Vehicle according to claim 2, wherein the control unit (200) delays the starting of the internal combustion engine (10) until the deterioration diagnosis process is completed. Vehicle according to claim 1, wherein the control unit (200) releases the suppression of starting the internal combustion engine (10) when the deterioration diagnosis process is completed. Vehicle according to claim 1, wherein, when the prescribed condition is met, the control unit (200), based on one of the amounts of charge and discharge of the energy storage device, diagnoses whether the energy storage device (70) has deteriorated, or whether it has not, when a voltage of the energy storage device (70) is changed from a diagnostic start voltage to a diagnostic end voltage. Vehicle according to claim 5, wherein the control unit (200) suppresses the starting of the internal combustion engine (10) while the voltage of the energy storage device (70) is changed from the diagnostic start voltage to the diagnostic end voltage. Vehicle according to claim 5, wherein the control unit (200) suppresses the starting of the internal combustion engine (10) while the voltage of the energy storage device (70) is changed from a prescribed voltage between the diagnostic start voltage and the diagnostic end voltage to the diagnostic end voltage. Vehicle according to claim 1, which further includes: an energy conversion device (60) for converting energy from the energy storage device (70) into energy supplied to the rotary electric machine (20), wherein the control unit (200) suppresses the starting of the internal combustion engine (10) by controlling the energy conversion device (60) to interrupt the supply of energy to the rotary electric machine (20). Deterioration diagnostic procedure for an energy storage device used in a vehicle (1) comprising an internal combustion engine (10), an energy storage device (70), and a rotary electric machine (20) for receiving an energy input from the energy storage device (70) and for starting the internal combustion engine (10), wherein the deterioration diagnostic procedure comprises the steps of: detecting a state of the energy storage device (70), performing a deterioration diagnostic process to diagnose, based on the state of the energy storage device (70), whether the energy storage device (70) has deteriorated or not, if a prescribed condition is met, and suppressing a starting of the internal combustion engine (10) if a condition for starting the internal combustion engine (10) is met.after the prescribed condition for carrying out the deterioration diagnosis process has been met and before the deterioration diagnosis process has been completed.

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