JP6588407B2 - Battery heating system - Google Patents

Description

  The present invention relates to a battery temperature raising system including a heater for raising a temperature of a driving battery.

  Conventionally, as described in Patent Document 1, in a vehicle including a traveling motor and a driving battery that supplies electric power to the traveling motor, a configuration in which the temperature of the driving battery is raised by a heater at a low temperature is known. ing. In this configuration, when external charging is performed from the external power source to the driving battery, when the battery temperature of the driving battery is lower than the target temperature, the heating relay is turned on to drive the heater.

Japanese Patent Laying-Open No. 2015-225787

  Incidentally, in the configuration described in Patent Document 1, either a heater for raising the temperature of the driving battery or a temperature raising relay connected between the heater and the auxiliary battery is detected by detecting a failure or the like. May be replaced. In this case, it is conceivable to perform normality determination processing for determining whether the heater and the temperature raising relay normally operate after the replacement of the heater or the temperature raising relay. In the normality determination process, the temperature rising relay is turned on, and it is determined whether or not it is normal from the temperature rising state of the heater. At this time, in the configuration described in Patent Document 1, when the target temperature for turning on the heating relay is a low temperature such as 0 degrees, the environmental temperature is not low after the replacement in the summer or during the day In addition, the temperature increasing relay for performing the normality determination process is not turned on. Thereby, it cannot be determined whether a heater and a temperature rising relay are normal.

  An object of the present invention is to provide a battery temperature raising system that enables execution of normality determination processing even when the heater or temperature raising relay is replaced even in a low-temperature environment.

  A battery temperature raising system according to the present invention includes a driving battery that supplies electric power to a vehicle driving motor, a heater that raises the temperature of the driving battery when electric power is supplied from an auxiliary battery, A temperature rising relay for connecting or disconnecting a power path between the auxiliary battery and the heater, a battery temperature sensor for detecting a battery temperature of the driving battery, a heater temperature sensor for detecting the temperature of the heater, and the rising temperature A control unit for controlling the temperature relay. The controller performs charge temperature increase control to switch the temperature increase relay from off to on when the driving battery is being charged from an external power source and the battery temperature is equal to or lower than a first threshold temperature. After the replacement of the heater or the temperature raising relay, when the battery temperature is equal to or lower than the second threshold temperature higher than the first threshold temperature, the temperature raising relay is turned on, A normal determination process for determining whether or not the heater and the temperature raising relay are normal is performed. When the battery temperature exceeds the second threshold temperature, the temperature raising relay is turned off and the normality determination process is not performed. .

  According to the battery temperature raising system of the present invention, the normality determination process can be executed even after the replacement of the heater or the temperature raising relay even in a low temperature environment.

1 is an overall configuration diagram of a battery temperature raising system according to an embodiment of the present invention. It is a figure which shows the change about the time of the battery temperature at the time of external charging, and the temperature increase request flag of a heater. It is a flowchart which shows the method of determining whether a temperature rising relay is turned on for normal determination in each driving trip. It is a figure which shows the temperature change of a heater in a normal determination process.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, identical elements are denoted by the same reference symbols in all drawings. In the description in the text, the symbols described before are used as necessary.

  FIG. 1 is an overall configuration diagram of a battery temperature raising system 12 according to an embodiment. The temperature raising system 12 can be suitably used in an electric vehicle or a plug-in hybrid vehicle in which the driving battery 13 is charged by an external power source 60 that is a commercial power source from a household outlet. In addition, the materials, the number, and the numerical values described below are examples for explanation, and can be appropriately changed according to the specifications of the battery temperature raising system. Hereinafter, a plug-in hybrid vehicle in which the driving battery 13 can be charged by the external power source 60 will be described.

  As shown in FIG. 1, the hybrid vehicle 10 on which the battery temperature raising system 12 is mounted travels using one or both of the second motor generator 30 and the engine 50 as a drive source. Specifically, the hybrid vehicle 10 includes a drive battery 13, a second motor generator 30, an engine 50, a first motor generator 32, an inverter device 34, and a control unit 20. The driving battery 13 and the control unit 20 constitute a temperature raising system 12 described later. Hereinafter, the first motor generator 32 is referred to as a first MG 32, and the second motor generator 30 is referred to as a second MG 30. In FIG. 1, the first MG 32 and the second MG 30 are indicated as MG1 and MG2, respectively. The second MG 30 corresponds to a traveling motor.

  The drive battery 13 is connected to the inverter device 34 via the positive electrode line PL and the negative electrode line NL. A system main relay 35 is provided in each of the positive electrode line PL and the negative electrode line NL. When a start instructing unit (not shown) such as a start switch or a start button of the vehicle is operated from off to on by a user, a control unit 20 described later is activated and the system main relay 35 is switched from off to on. . As a result, the drive battery 13 is connected to the inverter device 34, and the control system of the hybrid vehicle 10 becomes ReadyON which is in the activated state.

  When the start instruction unit of the vehicle is operated from on to off, the control unit 20 is activated and stopped, and the system main relay 35 is switched from on to off. As a result, the connection between the drive battery 13 and the inverter device 34 is disconnected, and the hybrid vehicle control system becomes ReadyOFF, which is in the start-stop state.

  Inverter device 34 includes an inverter (not shown) for first MG 32 and an inverter (not shown) for second MG 30. Thereby, the drive battery 13 supplies power to the second MG 30 and the first MG 32. The first MG inverter drives the first MG 32, and the second MG inverter drives the second MG 30.

  The driving battery 13 is a high voltage battery having a voltage between terminals of about 200 volts, for example. The driving battery 13 has one or a plurality of battery modules. The battery module includes a plurality of battery cells that are secondary batteries such as a nickel metal hydride battery or a lithium ion battery, and is configured by electrically connecting the plurality of battery cells in series or in parallel. The driving battery 13 may be a battery pack configured by electrically connecting a plurality of battery modules in series.

  Each of the first MG 32 and the second MG 30 has both functions of an electric motor and a generator. The first MG 32 is driven by electric power from the drive battery 13 and also has a function as a starter motor that starts the engine 50. The second MG 30 is driven by being supplied with electric power from the driving battery 13 and driving the vehicle. Specifically, the driving force of the second MG 30 is transmitted to the driving wheel 52 via the power split mechanism 51, and the driving wheel 52 is driven. The second MG 30 is also used as a power generator that charges the drive battery 13 by regenerative power generation during braking of the vehicle and supplying power to the drive battery 13.

  The engine 50 is connected to the power split mechanism 51 and can drive the drive wheels 52 by the driving force of the engine 50. Further, the driving force of the engine 50 is transmitted to the first MG 32 via the power split mechanism 51, whereby the first MG 32 is driven to generate power. The generated power is converted from alternating current to direct current by the inverter device 34 and then supplied to the driving battery 13, and the driving battery 13 is charged.

  A boost converter (not shown) may be connected between the system main relay 35 and the inverter device 34 in the positive electrode line PL and the negative electrode line NL. The boost converter boosts the voltage of the driving battery 13 to a voltage of about 600 V, for example, and supplies the boosted voltage to the inverter device 34.

  The control unit 20 is configured by a computer, for example, and includes a CPU that is a calculation unit and a storage unit such as a memory and a hard disk device. The control unit 20 controls various devices in the vehicle. For example, the control unit 20 receives signals representing detection values from various sensors such as an accelerator opening sensor (not shown) and a vehicle speed sensor (not shown) mounted on the vehicle. Based on the reception, control unit 20 controls the on / off operation of a switching element (not shown) of inverter device 34 to control the rotation speed or torque of second MG 30.

  The driving battery 13 can be connected to an external power source 60 through a charger (not shown) provided in the vehicle and a connector 61 such as a plug provided in the cable. With the external power supply 60 connected to the connector 61, the external power supply 60 is connected between the drive battery 13 and the system main relay 35 in each of the positive electrode line PL and the negative electrode line NL. Thereby, external charging, which is charging from the external power source 60 to the driving battery 13, is possible. The charger converts AC power from the external power source 60 into DC power for charging. The charger has a control circuit that varies the output power, and is adjusted by the control unit 20 to adjust the output power. The output power is supplied to the drive battery 13 and the drive battery 13 is charged. At this time, the system main relay 35 is turned off by the control unit 20.

  The temperature raising system 12 is used to raise the temperature of the driving battery 13. The temperature raising system 12 includes a driving battery 13 and a control unit 20, a heater 14, a temperature raising relay 15, an auxiliary battery 16, a battery temperature sensor 17, a heater temperature sensor 18, and an environmental temperature sensor 19.

  In the temperature raising system 12, as will be described later, when the driving battery 13 is charged from the external power source 60, the temperature raising relay 15 is turned on when the driving battery 13 is at a low temperature. Is supplied to the heater 14. Thereby, the heater 14 is driven, and the driving battery 13 is heated by the heater.

  The temperature rising relay 15 is a relay switch that is controlled by a control signal from the control unit 20 to connect or disconnect the power path between the auxiliary battery 16 and the heater 14. The auxiliary battery 16 is connected to a position between the system main relay 35 and the inverter device 34 via the DC / DC converter 36 in each of the positive electrode line PL and the negative electrode line NL. Thus, with the system main relay 35 turned on, the voltage of the drive battery 13 is stepped down to a low voltage of about 12 V by the DC / DC converter 36 and supplied to the auxiliary battery 16. The DC / DC converter 36 is controlled by the control unit 20. The auxiliary battery 16 supplies electric power to the auxiliary machine 37. The auxiliary machine 37 is, for example, a light, an air conditioner, a power steering device, a wiper, and an audio.

  The battery temperature sensor 17 detects the battery temperature of the driving battery 13. The heater temperature sensor 18 detects the temperature of the heater 14. The environmental temperature sensor 19 detects the temperature around the temperature raising system 12, for example, the outside air temperature outside the vehicle. Signals representing detection values from the battery temperature sensor 17, the heater temperature sensor 18, and the environmental temperature sensor 19 are transmitted to the control unit 20.

  The battery temperature sensor, heater temperature sensor, and environmental temperature sensor are each composed of, for example, a thermistor element whose electrical resistance changes with temperature and an insulator such as a resin having high thermal conductivity, and covers the periphery of the thermistor element. And a protective insulating portion for protecting the thermistor element.

  The control unit 20 may include an HV integrated ECU (electronic control unit) and a battery ECU, and these ECUs may communicate with each other bidirectionally via a cable.

  Further, the auxiliary battery 16 supplies power to the heater 14 via the temperature raising relay 15. The heater 14 is composed of, for example, an electric heater that converts electric energy into heat energy.

  The control unit 20 controls opening / closing of the temperature raising relay 15 based on a signal from the battery temperature sensor 17. FIG. 2 is a diagram illustrating a change with respect to time of the battery temperature and the temperature increase request flag of the heater 14 during external charging. For example, the control unit 20 performs temperature increase control during charging during external charging from the external power source 60 to the driving battery 13. The temperature increase control during charging is started when the control unit 20 detects the start of external charging, for example, by connecting the connector 61 to the external power source 60. When the battery temperature detected by the battery temperature sensor 17 becomes equal to or lower than the first threshold temperature T1 set in advance, the temperature increase request flag set by the control unit 20 is switched from off to on. The temperature raising relay 15 is on / off controlled in accordance with the temperature raising request flag. The first threshold temperature T1 is a temperature around 0 ° C., for example. Thereby, the control unit 20 switches the temperature rising relay 15 from off to on. And the control part 20 maintains the ON state of the temperature rising relay 15 until battery temperature reaches 3rd threshold temperature T3 set beforehand. The third threshold temperature T3 is higher than the first threshold temperature T1.

  In the temperature rise control during charging, the environmental temperature, which is the temperature detected by the environmental temperature sensor 19, is equal to or lower than the fourth threshold temperature T4 lower than the first threshold temperature T1 (T4 <T1), and the battery temperature is the first threshold temperature T1. In the following cases, the temperature raising relay 15 may be turned on.

  With the temperature raising relay 15 turned on, the auxiliary battery 16 supplies power to the heater 14 and drives the heater 14 to raise the temperature of the driving battery 13. When the vehicle is used in a cold region, if the electrolyte of the drive battery 13 freezes in an extremely low temperature environment, power cannot be supplied from the drive battery 13 to the first MG 32 and the second MG 30 and the vehicle cannot travel. . Further, when the temperature of the driving battery 13 is low, the charge / discharge performance of the driving battery 13 is lowered. The heater 14 raises the temperature of the driving battery 13 to a temperature at which the electrolyte of the driving battery 13 can be prevented from freezing or the charge / discharge performance of the driving battery 13 can be sufficiently secured.

  The temperature rise control during charging is performed so that the temperature rise relay 15 is turned on when a first condition in which the battery temperature is equal to or lower than the first threshold temperature T1 and a condition different from the first condition are satisfied. Good. For example, when the departure time is set in advance by the user and the scheduled time to start turning on the temperature rising relay 15 has elapsed so that the temperature increase ends within a predetermined time immediately before the departure time. The temperature raising relay may be turned on when the first condition is satisfied. At this time, for example, an estimated temperature increase time from when the temperature increase relay 15 is turned on until the battery temperature reaches the third threshold temperature T3 is calculated, and the temperature increase relay 15 is started to be turned on from the temperature increase estimated time. Time can be calculated.

  Furthermore, in the temperature raising system 12, the heater or the temperature raising relay may be replaced when the heater 14 or the temperature raising relay 15 is detected during use. For example, there may be a sticking abnormality in which the heating relay 15 is stuck in an on or off state. After the heater 14 or the temperature raising relay 15 is replaced by an operator such as a repair shop, the temperature raising system 12 is normal for determining whether or not the heater 14 and the temperature raising relay 15 are normally operated. Execute the judgment process. In the “normality determination process”, the temperature rise relay 15 is turned on, and it is determined whether the heater 14 is normal from the temperature rise state. By determining the normality in the normality determination process, for example, a failure history (DTC) that is failure diagnosis information described later can be deleted. The failure history is a code for identifying a failed component. When a predetermined failure diagnosis program is executed by the control unit 20 and a failure is detected in the diagnosed component, the diagnosis and component are stored in the storage unit of the control unit. A failure history corresponding to is stored. When a worker connects a terminal device (not shown) such as a failure diagnosis tool to the control unit 20 at a repair shop or the like, the failure history can be read by the terminal device. The read failure history is displayed on the display unit of the terminal device. By displaying the failure history, the operator can confirm that there is still a failure part. Even if a failed part is replaced with a new part, the failure history will not be erased unless it is determined to be normal by the normal determination process. Therefore, the operator does not know whether or not the failure part is actually present, and confuses the operator. Cause.

  On the other hand, in the charge temperature increase control described above, the first threshold temperature T1 that is a threshold for turning on the temperature increase relay 15 is a low temperature such as 0 degrees, and the drive battery 13 is equal to or lower than the first threshold temperature. The temperature raising relay 15 is turned on. In this case, when the environmental temperature such as the outside air temperature is not low after replacement of the heater or the temperature raising relay, the battery temperature of the driving battery 13 is a temperature close to the environmental temperature and higher than the first threshold temperature T1. It becomes temperature. As a result, the temperature increase relay 15 is not turned on only by the above-described temperature increase control during charging, and normality determination processing cannot be performed. As a result, there is a possibility that an inconvenience that the opportunity for executing the normality determination process is limited.

  Therefore, in the embodiment, in order to eliminate this inconvenience, the control unit 20 performs the following process. Specifically, the control unit 20 is after the replacement of the heater 14 or the temperature raising relay 15, and the battery temperature is higher than the first threshold temperature T1 and is equal to or lower than the second threshold temperature T2, which is a preset temperature. In this case, the temperature rising relay 15 is turned on to perform normality determination processing. The second threshold temperature T2 is a temperature considerably higher than the normal outside air temperature, such as 50 ° C., for example. At such a high temperature, turning on the temperature raising relay 15 and heating by the heater 14 may cause a problem for the driving battery 13 and other devices. For this reason, when the battery temperature exceeds the second threshold temperature T2, the control unit 20 turns off the temperature raising relay 15 and does not perform normality determination processing.

  Next, a method of determining whether to turn on the temperature rising relay 15 for normality determination processing will be described using the flowchart shown in FIG. FIG. 3 is a flowchart showing a method for determining whether or not to turn on the temperature rising relay 15 for normality determination in each traveling trip.

  For example, in each of “travel trips” that are a plurality of system activation states, it is determined whether or not to turn on the temperature raising relay 15 for normality determination. Each traveling trip means a state from ReadyON to ReadyOFF. A program for executing the flowchart shown in FIG. 3 is stored in the storage unit of the control unit 20 and is executed when the control unit 20 is activated.

  When the control unit 20 is activated by the user's turning-on operation of the start instruction unit (becomes ReadyON state), in step S11, it is determined whether or not it is determined to be normal in the normal determination process in the previous travel trip. Hereinafter, step S is simply referred to as S.

  If the determination result in S11 is YES, it is not necessary to perform further normality determination processing, so the failure history (DTC) of the temperature rising relay 15 or the heater 14 stored in the storage unit of the control unit 20 is deleted. (S12). And a process is complete | finished in the state which turned off the temperature rising relay 15 (S13). At this time, the process of the flowchart of FIG. 3 is not resumed until the start instruction unit is turned on again and becomes Ready ON after the user turns OFF the start instruction unit.

  On the other hand, if the determination result in S11 is NO, in S14, it is determined whether or not the initial check flag is off and a failure history (DTC) is stored in the storage unit. Here, the fact that the initial check flag is OFF means that the connection between the terminal of the auxiliary battery 16 and the electrical component has been disconnected. When the temperature raising relay 15 or the heater 14 is replaced, the connection between the terminal of the auxiliary battery 16 and the electrical component is disconnected. Thereby, when the initial check flag is OFF, it is determined that there is a possibility that the temperature increasing relay 15 or the heater 14 has been replaced.

  If the determination result in S14 is YES, it is determined in S15 whether or not there is a predetermined travel history and the travel control mode is in effect. The presence of the predetermined traveling history means that the storage unit stores that the worker has traveled the vehicle in a predetermined traveling pattern after replacing the heating relay 15 or the heater 14 in the vehicle repair shop. Traveling in a predetermined travel pattern is defined as necessary travel performed after completion of work at a repair shop. By this traveling, it is possible to confirm the presence or absence of defects in the vehicle after the work is completed. Further, the driving battery 13 is not connected to the external power source 60 during the traveling control mode.

  If the determination result in S15 is YES, the predetermined voltage is such that the battery temperature is not more than the second threshold temperature T2 in S17 and the auxiliary battery voltage of the auxiliary battery 16 can exhibit the desired performance. It is determined whether it is within the range. For this determination, a special voltage sensor is not used, and it is determined by the self-diagnosis function of the control unit 20 whether the voltage is within a predetermined voltage range.

  If the determination result in S17 is YES, normal determination processing is executed in S19. That is, the temperature raising relay 15 is turned on for normality determination.

  Here, the normality determination process will be described with reference to FIG. FIG. 4 is a diagram illustrating a temperature change of the heater 14 in the normality determination process. Execution of the normality determination process is started by turning on the temperature raising relay 15. Thereby, electric power is supplied from the auxiliary battery 16 to the heater 14 and the heater 14 is heated. And the control part 20 acquires the temperature rising condition of the heater 14 from the detection value of the heater temperature sensor 18. FIG. In FIG. 4, the horizontal axis indicates the elapsed time since the heating relay 15 is turned on, and the vertical axis indicates the temperature of the heater 14. The temperature rising relay 15 is turned off when a predetermined normality determination processing time t2 elapses from when the temperature rising relay 15 starts to be turned on. Further, the temperature raising relay 15 is also turned off even when the temperature of the heater becomes equal to or higher than a predetermined normal determination temperature Tα before the normal determination processing time t2 elapses. At this time, it is determined that the temperature of the heater is rapidly increased, and is determined to be normal in the normal determination process. In FIG. 4, when the temperature of the heater rises as indicated by the straight line P1 and the temperature of the heater reaches the normal determination temperature Tα at time t2, it is determined to be normal. On the other hand, when the elapsed time from the turn-on of the temperature raising relay 15 becomes the normal determination processing time t2, the heater temperature is lower than the normal determination temperature Tα in the example of the straight line P2 in FIG. To finish the process. In this case, the heater temperature is equal to or higher than the abnormality determination temperature Tβ, and it is not determined that the heater and the temperature raising relay are abnormal. At this time, the same processing is repeated in the next traveling trip. On the other hand, when the temperature of the heater is lower than the abnormality determination temperature Tβ when the normal determination processing time t2 has elapsed, it is determined that the heater or the temperature raising relay is abnormal. At this time, for example, the control unit generates a signal indicating abnormality and notifies the operator or user by a notification unit (not shown) such as a display unit, a warning sound, or a warning light. In the embodiment, since the time from turning on to off of the temperature raising relay 15 is limited to the normal determination processing time t2, the determination processing time can be shortened.

  Returning to FIG. 3, after the temperature raising relay is turned on in S19, it is determined in S20 whether or not the normal determination processing time t2 has ended. If the determination result in S20 is YES, the temperature increase request flag is turned off in S21, and the temperature increase relay 15 is turned off in S13. At this time, if the heater temperature is lower than the abnormality determination temperature Tβ as described above, a signal indicating abnormality is generated.

  If the determination result in S20 is NO, it is determined whether or not the heater temperature is equal to or higher than the normal determination temperature Tα (S22). If the determination result in S22 is YES, it is determined that the temperature is normal, the temperature increase request flag is turned off in S21, and the temperature increase relay 15 is turned off in S13. In this case, the failure history (DTC) is still stored in the storage unit, and the failure history is deleted in S12 when the flowchart of FIG. 3 is executed in the next travel trip. On the other hand, if the determination result in S22 is NO, the process returns to S20 and is repeated.

  After the processing of S13, the flowchart of FIG. 3 is not executed until the start instruction unit is turned on again and becomes Ready ON after the user turns off the start instruction unit.

  On the other hand, when the determination result of S14 is NO, it is not after the temperature increasing relay 15 or the heater 14 is replaced, or there is no failure history, or both. The case where there is no failure history includes the case where the failure history is deleted in S12 described above. Therefore, when the determination result in S14 is NO, it is determined that the normal determination process is completed in S16 or the normal determination process is unnecessary, and the initial check flag is turned on and the temperature increase request flag is set. Turn off. And it transfers to S13 and complete | finishes a process in the state which turned off the temperature rising relay 15 as mentioned above.

  Further, when the determination result in S15 is NO, the vehicle has not yet reached the state where the normal determination process is executed, for example, the vehicle has not completed traveling in the predetermined traveling pattern. For this reason, in S18, the temperature increase request flag is turned off because it is in the standby state of the normality determination process, and the process ends with the temperature increase relay 15 turned off as described above (S13).

  If the determination result in S17 is NO, the process proceeds to S18 as in the case where the determination result in S15 is NO.

  According to the temperature raising system 12 described above, after the heater 14 or the temperature raising relay 15 is replaced, even if the environmental temperature is not a low temperature such as 0 ° C. or is not a low temperature environment, the battery temperature is not more than the first threshold temperature T1. The low temperature does not become a condition for the ON operation of the temperature raising relay 15. Thereby, even if it is not a low temperature environment, since a normal determination process can be performed, it can prevent that the opportunity which can perform a normal determination process is limited.

  In the process shown in FIG. 3, the failure history erasure condition in S12 may be that the previous normal determination process is normal in S11 and that the previous normal determination process is also normal. As a result, the condition for erasing the failure history can be made stricter from the viewpoint of safety.

  DESCRIPTION OF SYMBOLS 10 Hybrid vehicle, 12 Temperature rising system, 13 Drive battery, 14 Heater, 15 Temperature rising relay, 16 Auxiliary battery, 17 Battery temperature sensor, 18 Heater temperature sensor, 19 Environmental temperature sensor, 20 Control part, 30 2nd Motor generator (2nd MG), 32 1st motor generator (1st MG) 34 Inverter device, 35 System main relay, 36 DC / DC converter, 37 Auxiliary machine, 50 Engine, 51 Power split mechanism, 52 Drive wheel, 60 External power supply 61 connector.

Claims (1)

A driving battery for supplying electric power to a vehicle driving motor;
A heater that raises the temperature of the driving battery when power is supplied from the auxiliary battery;
A heating relay that connects or disconnects the power path between the auxiliary battery and the heater;
A battery temperature sensor for detecting a battery temperature of the driving battery;
A heater temperature sensor for detecting the temperature of the heater;
A controller for controlling the temperature raising relay,
The controller performs charge temperature increase control to switch the temperature increase relay from off to on when the driving battery is being charged from an external power source and the battery temperature is equal to or lower than a first threshold temperature. After the replacement of the heater or the temperature raising relay, when the battery temperature is equal to or lower than a second threshold temperature higher than the first threshold temperature, the temperature raising relay is turned on, A normal determination process for determining whether or not the heater and the temperature raising relay are normal is performed. When the battery temperature exceeds the second threshold temperature, the temperature raising relay is turned off and the normality determination process is not performed. Battery heating system.

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