POWER SUPPLY DEVICE

A power supply device includes: a first battery; a plurality of first temperature sensors that is attached to the first battery; a second battery that is provided adjacent to the first battery; and a plurality of second temperature sensors that is attached to the second battery. A high-temperature abnormality of the second battery is diagnosed using a second abnormality diagnosis method based on temperatures from the plurality of second temperature sensors when a high-temperature abnormality has been detected in the first battery using a first abnormality diagnosis method different from the second abnormality diagnosis method based on temperatures from the plurality of first temperature sensors.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2020-147638 filed on Sep. 2, 2020, incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a power supply device and more particularly to a power supply device including a first battery and a second battery.

2. Description of Related Art

In the related art, a power supply device including a first power supply device including a first battery, a first control unit that controls charging/discharging of the first battery, and a first monitoring unit that monitors the first battery and a second power supply device including a second battery, a second control unit that controls charging/discharging of the second battery, and a second monitoring unit that monitors the second battery has been proposed as a type of power supply device (for example, see Japanese Unexamined Patent Application Publication No. 2019-92335 (JP 2019-92335 A)). In this device, when the second monitoring unit of the second power supply device has detected an abnormality in the second battery, the first monitoring unit of the first power supply device acquires a second battery state from the second monitoring unit of the second power supply device and generates availability information indicating whether the second battery is available based on a first battery state and the second battery state. The second control unit of the second power supply device acquires the availability information generated by the first power supply device and controls charging/discharging of the second battery based on the acquired availability information.

SUMMARY

A power supply device including a first battery and a second battery often diagnoses a high-temperature abnormality of the first battery depending on whether a temperature of one of a plurality of temperature sensors attached to the first battery is equal to or greater than a threshold value, and diagnoses a high-temperature abnormality of the second battery depending on whether a temperature of one of a plurality of temperature sensors attached to the second battery is equal to or greater than a threshold value. In a power supply device in which a first battery and a second battery are provided adjacent to each other, when a high-temperature abnormality has been detected in the first battery and a high-temperature abnormality has not occurred in the second battery, it may be diagnosed that the high-temperature abnormality has occurred in the second battery when a temperature from a temperature sensor closest to the first battery out of a plurality of temperature sensors attached to the second battery is higher than a threshold value due to a high temperature of the first battery.

The present disclosure provides a power supply device that includes a first battery and a second battery which are provided adjacent to each other and that can appropriately diagnose a high-temperature abnormality in the second battery when it is diagnosed that a high-temperature abnormality has occurred in the first battery.

The power supply according to the present disclosure employs the following configurations.

According to an aspect of the present disclosure, there is provided a power supply device including: a first battery; a plurality of first temperature sensors that is attached to the first battery; a second battery that is provided adjacent to the first battery; a plurality of second temperature sensors that is attached to the second battery; and a control unit configured to manage the first battery and the second battery. The control unit is configured to diagnose a high-temperature abnormality of the second battery using a second abnormality diagnosis method based on temperatures from the plurality of second temperature sensors when a high-temperature abnormality has been detected in the first battery using a first abnormality diagnosis method different from the second abnormality diagnosis method based on temperatures from the plurality of first temperature sensors.

In the power supply device according to the aspect of the present disclosure, when a high-temperature abnormality in the first battery has been detected using the first abnormality diagnosis method based on the temperatures from the plurality of first temperature sensors attached to the first battery, a high-temperature abnormality in the second battery is diagnosed using the second abnormality diagnosis method which is different from the first abnormality diagnosis method based on the temperatures from the plurality of second temperature sensors attached to the second battery. Accordingly, it is possible to appropriately diagnose a high-temperature abnormality in the second battery when a high-temperature abnormality in the first battery has been diagnosed.

In the power supply device according to the aspect of the present disclosure, the first abnormality diagnosis method may be a method of diagnosing that the high-temperature abnormality has occurred in the first battery when the temperature from one of the plurality of first temperature sensors is equal to or greater than a first threshold value. The second abnormality diagnosis method may be a method of diagnosing that the high-temperature abnormality has occurred in the second battery when the temperature from all of the plurality of second temperature sensors is equal to or greater than a second threshold value. With this configuration, even when only the temperature from the temperature sensor provided closest to the first battery out of the plurality of second temperature sensors is equal to or greater than the second threshold value, a high-temperature abnormality in the second battery is not diagnosed. Accordingly, it is possible to appropriately diagnose a high-temperature abnormality in the second battery when a high-temperature abnormality in the first battery has been diagnosed. Here, the second threshold value may be the same value as the first threshold value or may be a value different therefrom. The first threshold value is set to a temperature which is lower than a temperature at which an abnormality such as deformation is caused in the first battery, and the second threshold value is set to a temperature which is lower than a temperature at which an abnormality such as deformation is caused in the second battery.

In the power supply device according to the aspect of the present disclosure, the control unit may be configured to limit charging of the second battery when it is not diagnosed using the second abnormality diagnosis method that the high-temperature abnormality has occurred in the second battery in a state in which the high-temperature abnormality is detected in the first battery and when a change in temperature per predetermined time from one temperature sensor other than the temperature sensor provided closest to the first battery out of the plurality of second temperature sensors is equal to or greater than a predetermined change. The limiting of charging of the second battery includes prohibition of charging of the second battery. With this configuration, it is possible to curb an increase in temperature of the second battery and to curb detection of a high-temperature abnormality in the second battery at the same time at which a high-temperature abnormality in the first battery has been detected.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1is a diagram schematically illustrating a configuration of a hybrid vehicle20in which a power supply device according to an embodiment of the present disclosure is mounted. As illustrated inFIG. 1, the hybrid vehicle20according to this embodiment includes an engine22, a motor30, an inverter32, a clutch36, an automatic gear shift device40, a high-voltage battery60, a low-voltage battery67, a DC/DC converter68, and a hybrid electronic control unit (hereinafter referred to as an “HVECU”)70.

The engine22is configured as a multi-cylinder (such as four-cylinder or six-cylinder) internal combustion engine that outputs power using fuel such as gasoline or diesel oil which is supplied from a fuel tank via a fuel supply system through four strokes including intake, compression, expansion (explosive combustion), and exhaust strokes. The operation of the engine22is controlled by an engine electronic control unit (hereinafter referred to as an “engine ECU”)24.

Although not illustrated, the engine ECU24is configured as a microprocessor including a CPU as a major component and includes a ROM that stores a processing program, a RAM that temporarily stores data, input and output ports, and a communication port in addition to the CPU. Signals from various sensors required for controlling the operation of the engine22are input to the engine ECU24via the input port. Various control signals for controlling the operation of the engine22are output from the engine ECU24via the output port.

A starter motor25that cranks the engine22is connected to a crank shaft23which is an output shaft of the engine22. An input side of a damper28which is a torsion element is also connected to the crank shaft23of the engine22.

The motor30is configured as, for example, a synchronous power generation motor. The inverter32is used to drive the motor30and is connected to a high-voltage power line61. The motor30is rotationally driven by controlling switching of a plurality of switching elements of the inverter32using the HVECU70. The clutch36is configured as, for example, a hydraulic frictional clutch and performs engagement and disengagement between an output side of the damper28and a rotation shaft of the motor30.

The automatic gear shift device40includes a torque converter43, a six-stage automatic transmission45, and a hydraulic circuit which is not illustrated. The torque converter43is configured as a general fluidic transmission device and transmits power of an input shaft41connected to the rotation shaft of the motor30to the intermediate rotation shaft44which is an input shaft of the automatic transmission45with an amplified torque or without amplifying a torque. The automatic transmission45is connected to the intermediate rotation shaft44and an output shaft42connected to the drive shaft46and includes a plurality of planetary gears and a plurality of frictional engagement elements (clutches and brakes) which are hydraulically driven. The drive shaft46is connected to rear wheels55aand55bvia an axle56and a rear differential gear57. The automatic transmission45forms first to sixth forward stages and a reverse stage and transmits power between the intermediate rotation shaft44and the output shaft42, for example, by engagement and disengagement of the plurality of frictional engagement elements.

The high-voltage battery60is configured as, for example, a lithium-ion secondary battery and is connected to the high-voltage power line61along with the inverter32. A plurality of temperature sensors60ato60care attached to the high-voltage battery60. The low-voltage battery67is configured as, for example, a lead storage battery of which the rated voltage is lower than that of the high-voltage battery60and is connected to a low-voltage power line66connected to auxiliary machinery such as the starter motor25. A plurality of temperature sensors67ato67care attached to the low-voltage battery67. The high-voltage battery60and the low-voltage battery67are provided adjacent to each other in an arrangement platform62. The DC/DC converter68is connected to the high-voltage power line61and the low-voltage power line66. The DC/DC converter68is controlled by the HVECU70such that electric power of the high-voltage power line61is supplied to the low-voltage power line66with a voltage drop.

Although not illustrated, the HVECU70is configured as a microprocessor including a CPU as a major and includes a ROM that stores a processing program, a RAM that temporarily stores data, input and output ports, and a communication port in addition to the CPU. Signals from various sensors are input to the HVECU70via the input port. Examples of the signals input to the HVECU70include a rotational position ϕm of a rotor of the motor30from a rotational position sensor (for example, a resolver)30athat detects a rotational position of the rotor of the motor30and a rotation speed Np of the drive shaft46from a rotation speed sensor46athat is attached to the drive shaft46. Examples thereof include a voltage Vh of the high-voltage battery60from a voltage sensor that is attached between terminals of the high-voltage battery60, a current Ih of the high-voltage battery60from a current sensor that is attached to an output terminal of the high-voltage battery60, and a voltage Vb of the low-voltage battery67from a voltage sensor that is attached between terminals of the low-voltage battery67. Examples thereof include temperatures from the plurality of temperature sensors60ato60cattached to the high-voltage battery60and temperatures from the plurality of temperature sensors67ato67cattached to the low-voltage battery67. Examples thereof include an ignition signal from an ignition switch80, a shift position SP from a shift position sensor82that detects an operation position of a shift lever81, an accelerator operation amount Acc from an accelerator pedal position sensor84that detects an amount of depression of an accelerator pedal83, a brake pedal position BP from a brake pedal position sensor86that detects an amount of depression of a brake pedal85, and a vehicle speed V from a vehicle speed sensor88.

Various control signals are output from the HVECU70via the output port. Examples of the signals output from the HVECU70include a control signal for the starter motor25, a control signal for the inverter32, a control signal for the clutch36, a control signal for the automatic gear shift device40, and a control signal for the DC/DC converter68. The HVECU70is connected to the engine ECU24via the communication port.

The high-voltage battery60, the low-voltage battery67, the plurality of temperature sensors60ato60cand67ato67c, and the HVECU70correspond to a power supply device.

An operation of the power supply device that is mounted in the hybrid vehicle20according to the embodiment having the aforementioned configuration, that is, an operation of diagnosing a high-temperature abnormality in the low-voltage battery67when a high-temperature abnormality in the high-voltage battery60has been diagnosed, will be described below. A high-temperature abnormality in the high-voltage battery60is diagnosed, for example, when a temperature from one temperature sensor out of the plurality of temperature sensors60ato60cattached to the high-voltage battery60is equal to or higher than a first threshold value Tref1. The first threshold value Tref1is predetermined as a temperature which is lower than a temperature at which an abnormality such as deformation occurs in cells of the high-voltage battery60and, for example, 65° C., 70° C., or 75° C. can be used.FIG. 2is a flowchart illustrating an example of an abnormality diagnosis process which is performed by the HVECU70when a high-temperature abnormality of the low-voltage battery67is diagnosed. The abnormality diagnosis process is repeatedly performed at predetermined time intervals (for example, at intervals of several tens of msec).

When the abnormality diagnosis process is performed, the HVECU70first performs a process of inputting the temperatures TLa to TLc detected by the temperature sensors67ato67cattached to the low-voltage battery67(Step S100). Subsequently, the HVECU70determines whether a high-temperature abnormality has been diagnosed (a high-temperature abnormality has occurred) in the high-voltage battery60(Step S110). Diagnosis of a high-temperature abnormality in the high-voltage battery60is the same as described above. When it is determined that a high-temperature abnormality has not been diagnosed (a high-temperature abnormality has not occurred) in the high-voltage battery60, the HVECU70diagnoses a high-temperature abnormality in the low-voltage battery67using a normal diagnosis method (Step S120) and ends this routine. Similarly to a method of diagnosing a high-temperature abnormality in the high-voltage battery60, a method of diagnosing that a high-temperature abnormality has occurred in the low-voltage battery67when one of the temperatures TLa to TLc detected by the temperature sensors67ato67cis equal to or greater than a second threshold value Tref2can be used as the normal diagnosis method. The second threshold value Tref2is predetermined as a temperature which is lower than a temperature at which an abnormality such as deformation occurs in the low-voltage battery67and, for example, 65° C., 70° C., or 75° C. can be used. The second threshold value Tref2may be the same temperature as the first threshold value Tref1or may be different therefrom.

When it is determined in Step S110that a high-temperature abnormality has been diagnosed (a high-temperature abnormality has occurred) in the high-voltage battery60, the HVECU70determines whether all of the temperatures TLa to TLc detected by the temperature sensors67ato67cattached to the low-voltage battery67are equal to or greater than the second threshold value Tref2(Step S130). When it is determined that all of the temperatures TLa to TLc are equal to or greater than the second threshold value Tref2, the HVECU70diagnoses that a high-temperature abnormality has occurred in the low-voltage battery67(Step S140), prohibits charging/discharging of the low-voltage battery67(Step S150), and ends this routine. The method of diagnosing a high-temperature abnormality in the low-voltage battery67in this case is different from the method of diagnosing a high-temperature abnormality in the low-voltage battery67in a normal state described above in Step S120(the same method as the method of diagnosing a high-temperature abnormality in the high-voltage battery60). Charging/discharging of the low-voltage battery67when a high-temperature abnormality has been diagnosed in the low-voltage battery67is prohibited to curb damage of the low-voltage battery67or the like.

When it is determined in Step S130that one of the temperatures TLa to TLc is less than the second threshold value Tref2(a high-temperature abnormality has not been diagnosed in the low-voltage battery67), the HVECU70calculates changes in temperature ΔTLb and ΔTLc of the temperatures TLb and TLc detected by the temperature sensors67band67cother than the temperature sensor67aclosest to the high-voltage battery60out of the plurality of temperature sensors67ato67cattached to the low-voltage battery67(Step S160). Specifically, the changes in temperature ΔTLb and ΔTLc are calculated by subtracting the temperatures TLb and TLc detected and input by the temperature sensors67band67cwhen the abnormality diagnosis process was previously performed from the temperatures TLb and TLc detected by the temperature sensors67band67c. In this case, the changes in temperature ΔTLb and ΔTLc are changes in temperature per start time interval of the abnormality diagnosis process. The changes in temperature ΔTLb and ΔTLc may be divided by the start time interval of the abnormality diagnosis process. In this case, changes in temperature per unit time are acquired.

Then, the HVECU70determines whether one of the changes in temperature ΔTLb and ΔTLc is equal to or greater than a third threshold value Tref3(Step S170). As the third threshold value Tref3, a value which is less than a change in temperature per start time interval of the abnormality diagnosis process when a high-temperature abnormality has occurred in the low-voltage battery67can be employed, and it can be determined in advance by experiment or the like. When it is determined that one of the changes in temperature ΔTLb and ΔTLc is equal to or greater than the third threshold value Tref3, the HVECU70determines that a high-temperature abnormality has not occurred in the low-voltage battery67but there is a likelihood that a high-temperature abnormality will occur, limits charging/discharging of the low-voltage battery67such that discharging of the low-voltage battery67is not limited but charging thereof is prohibited (Step S180), and ends this routine. Accordingly, it is possible to curb an increase in temperature of the low-voltage battery67and to prevent a high-temperature abnormality in the low-voltage battery67from being detected at the same time at which a high-temperature abnormality in the high-voltage battery60is detected.

When it is determined in Step S170that all of the changes in temperature ΔTLb and ΔTLc are less than the third threshold value Tref3, the HVECU70determines that there is no likelihood that a high-temperature abnormality will occur in the low-voltage battery67, performs charging/discharging of the low-voltage battery67normally (Step S190), and ends this routine.

In the power supply device which is mounted in the hybrid vehicle20according to the aforementioned embodiment, when it is determined that a high-temperature abnormality has been diagnosed (a high-temperature abnormality has occurred) in the high-voltage battery60, a high-temperature abnormality in the low-voltage battery67is diagnosed depending on whether all of the temperatures TLa to TLc detected by the temperature sensors67ato67cattached to the low-voltage battery67are equal to or greater than the second threshold value Tref2(using a diagnosis method different from the method of diagnosing a high-temperature abnormality in the high-voltage battery60). That is, in comparison with a case in which a high-temperature abnormality in the low-voltage battery67is diagnosed when the temperatures TLb and TLc detected by the temperature sensors67band67cother than the temperature sensor67aclosest to the high-voltage battery60out of the temperature sensors67ato67cattached to the low-voltage battery67are less than the second threshold value Tref2and the temperature TLa detected by the temperature sensor67ais equal to or greater than the second threshold value Tref2, it is possible to more appropriately diagnose a high-temperature abnormality in the low-voltage battery67when a high-temperature abnormality in the high-voltage battery60has been diagnosed.

In the power supply device which is mounted in the hybrid vehicle20according to the embodiment, when a high-temperature abnormality has not been diagnosed (a high-temperature abnormality has not occurred) in the low-voltage battery67in a state in which a high-temperature abnormality has been diagnosed in the high-voltage battery60and one of the changes in temperature ΔTLb and ΔTLc per start time interval of the abnormality diagnosis process of the temperatures TLb and TLc detected by the temperature sensors67band67cother than the temperature sensor67aclosest to the high-voltage battery60out of the temperature sensors67ato67cattached to the low-voltage battery67is equal to or greater than the third threshold value Tref3, charging/discharging of the low-voltage battery67is limited such that discharging of the low-voltage battery67is not limited but charging thereof is prohibited. Accordingly, it is possible to curb an increase in temperature of the low-voltage battery67and to prevent a high-temperature abnormality in the low-voltage battery67from being detected at the same time at which a high-temperature abnormality in the high-voltage battery60is detected.

In the power supply device which is mounted in the hybrid vehicle20according to the embodiment, when a high-temperature abnormality has not been diagnosed in the low-voltage battery67in a state in which a high-temperature abnormality has been diagnosed in the high-voltage battery60and one of the changes in temperature ΔTLb and ΔTLc of the temperatures TLb and TLc detected by the temperature sensors67band67cother than the temperature sensor67aclosest to the high-voltage battery60out of the temperature sensors67ato67cattached to the low-voltage battery67is equal to or greater than the third threshold value Tref3, charging/discharging of the low-voltage battery67is limited such that discharging of the low-voltage battery67is not limited but charging thereof is prohibited. However, charging of the low-voltage battery67may not be prohibited but limited to a certain extent or discharging of the low-voltage battery67as well as charging thereof may be slightly limited.

In the power supply device which is mounted in the hybrid vehicle20according to the embodiment, the power supply device is mounted in a hybrid vehicle20in which the starter motor25is connected to the crank shaft23of the engine22and the motor30is also connected to the crank shaft23via the clutch36. However, the power supply device may be mounted in a hybrid vehicle or an electric vehicle having various hardware configurations as long as the high-voltage battery60that supplies electric power to a driving motor and the low-voltage battery67that supplies electric power to auxiliary machinery or the like are provided. The power supply device may be mounted in a hybrid vehicle or an electric vehicle having various hardware configurations in which two high-voltage batteries that supply electric power to a driving motor are provided. The power supply device may be mounted in a vehicle or a mobile object other than an automobile as long as two batteries are provided, and may be assembled into a construction facility or the like.

Correspondence between principal elements of the embodiment and principal elements of the present disclosure described in the SUMMARY will be described below. In the embodiment, the high-voltage battery60corresponds to a “first battery,” the plurality of temperature sensors60ato60ccorresponds to a “plurality of first temperature sensors,” the low-voltage battery67corresponds to a “second battery,” the plurality of temperature sensors67ato67ccorresponds to a “plurality of second temperature sensors,” and the HVECU70corresponds to a “control unit.”

The correspondence between the principal elements in the embodiment and the principal elements of the present disclosure described in the does not limit the elements of the present disclosure described in the SUMMARY, because the embodiment is an example for specifically describing an aspect of the present disclosure described in the SUMMARY. That is, it should be noted that the present disclosure described in the SUMMARY has to be construed based on the description of the SUMMARY and the embodiment is only a specific example of the present disclosure described in the SUMMARY.

While an embodiment of the present disclosure has been described above, the applicable embodiment is not limited to the embodiment and can be modified in various forms without departing from the gist of the present disclosure.

The present disclosure is applicable to the manufacturing industry for power supply devices.