JP2016201321A - Temperature raising device for battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a battery electrolyte from being frozen for a longer period while suppressing an increase in power consumption of a heater.SOLUTION: During a first period until a lapsed time t from a plug-in state becomes a time t1, a first temperature rising control for maintaining a battery temperature Tb in a temperature range R1 is performed, original motor travelling performance being capable of being guaranteed in the temperature range R1, and, during a second period after the first period has elapsed, a second temperature rising control for maintaining the battery temperature Tb in a temperature range R2 is performed, temperatures in the temperature range R2 being lower than those in a target temperature range R1 and being higher than the temperature at which an electrolyte of a battery for drive is frozen.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a battery temperature raising device mounted on a vehicle that can be connected to an external power source.

  Japanese Patent Laying-Open No. 2011-238428 (Patent Document 1) discloses a temperature raising system including a heater that heats a battery from the outside, and a controller that raises the battery temperature by heating the battery with the heater. Yes. The control device operates the heater when the battery temperature is equal to or lower than a predetermined temperature, and stops the heater when a predetermined time has elapsed.

JP 2011-238428 A

  In the temperature raising system disclosed in Japanese Patent Application Laid-Open No. 2011-238428 (Patent Document 1), the heater is stopped when a predetermined time elapses, so that wasteful power consumption is suppressed. If the battery is left for a long period of time, the electrolyte of the battery may freeze, and the battery may not be able to be input / output at all.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to suppress freezing of the electrolyte solution of the battery for a longer period while suppressing an increase in power consumption of the heater.

  A temperature raising device according to the present invention is a battery temperature raising device that is mounted on a vehicle that can be connected to an external power source and configured to be rechargeable using electric power supplied from the external power source. And a control device that performs temperature increase control for heating the battery by heating the battery with the heater. The control device controls the heater to control the heater so that the temperature of the battery is equal to or higher than the first lower limit temperature until the first period elapses after the electric power can be supplied to the battery from the external power source. After temperature control is performed and the first period has elapsed, second temperature increase control is performed to control the heater so that the temperature of the battery is equal to or higher than the second lower limit temperature. The second lower limit temperature is lower than the first lower limit temperature and higher than the temperature at which the battery electrolyte freezes.

  According to such a configuration, the heater is continuously operated so that the temperature of the battery becomes equal to or higher than the second lower limit temperature even after the first period has elapsed. Since the second lower limit temperature is lower than the first lower limit temperature during the first period, the power consumption of the heater is suppressed more than during the first period. Furthermore, the second lower limit temperature is higher than the temperature at which the battery electrolyte freezes. Therefore, freezing of the battery electrolyte can be suppressed for a longer period while suppressing an increase in power consumption of the heater.

  Preferably, the vehicle generates the vehicle driving force by operating the motor using the electric power of the battery. The first lower limit temperature is a temperature at which the battery can output higher power to the motor than when the battery temperature is the second lower limit temperature.

  According to such a configuration, when the vehicle travel is started during the first period, the vehicle travel can be started with a larger vehicle driving force than when the vehicle travel is started after the first period.

  Preferably, the control device stops the second temperature increase control when the second period has elapsed since the start of the second temperature increase control.

  According to such a configuration, since it is assumed that the vehicle is not used when the second period has elapsed since the start of the second temperature increase control, the heater consumption is stopped by stopping the second temperature increase control. It can suppress that electric power increases wastefully.

Preferably, the second period is longer than the first period.
According to such a configuration, the second period with low power consumption is made longer than the first period with high power consumption, thereby suppressing the increase in power consumption of the heater and further freezing the electrolytic solution of the battery. The period can be suppressed.

  Preferably, the first temperature rise control is a control for operating and stopping the heater so as to maintain the temperature of the battery in a first temperature region that is equal to or higher than the first lower limit temperature and lower than the first upper limit temperature. The second temperature increase control is a control for operating and stopping the heater so as to maintain the temperature of the battery in a second temperature region that is equal to or higher than the second lower limit temperature and lower than the second upper limit temperature. The second upper limit temperature is lower than the first upper limit temperature.

  According to such a configuration, since the second upper limit temperature during the second period is lower than the first upper limit temperature during the first period, the power consumption of the heater during the second period is reduced by the consumption of the heater during the first period. It can be suppressed more than electric power.

1 is an overall configuration diagram of a vehicle. It is a figure which shows an example of the change of the battery temperature Tb by temperature rising control. It is a flowchart which shows the flow of a process of a control apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is an overall configuration diagram of a vehicle 1 provided with a battery temperature increasing device according to the present embodiment. The vehicle 1 includes a drive battery 10, a DC / DC converter 20, an auxiliary battery 30, a heater 40, a charger 50, an inlet 51, a timer 60, and a control device 100.

  The vehicle 1 is an electric vehicle that can travel by driving a motor (not shown) with electric power stored in the driving battery 10. The vehicle 1 may include an engine in addition to the motor as a power source. That is, the vehicle 1 may be an electric vehicle or a hybrid vehicle.

  The driving battery 10 is a secondary battery that stores electric power for operating the motor. The drive battery 10 includes, for example, lithium ion battery cells, nickel metal hydride battery cells, and the like.

  The DC / DC converter 20 steps down and outputs a high voltage system voltage (for example, about 200 volts) including the drive battery 10 to a low voltage system voltage (for example, about 12 volts) including the auxiliary battery 30. Thereby, the high-voltage power is also supplied to the low-pressure system. The DC / DC converter 20 is controlled based on a control signal from the control device 100.

  The auxiliary battery 30 is a secondary battery that stores electric power for operating auxiliary devices (such as the heater 40 and the control device 100) of the vehicle 1. The auxiliary battery 30 typically includes a lead storage battery. The voltage of the auxiliary battery 30 is a relatively low value of about 12 volts as described above.

  The heater 40 heats the driving battery 10 from the outside by generating Joule heat when energized. When the switch 41 is closed by a control signal from the control device 100, the heater 40 supplies power supplied from the auxiliary battery 30, power supplied from the driving battery 10 via the DC / DC converter 20, DC / DC Heat is generated by at least one of the electric power supplied from the external power source 200 via the converter 20.

  The inlet 51 is provided on the body surface of the vehicle 1 and is configured to be connectable to the connector 201 of the external power source 200. When the connector 201 of the external power source 200 is connected to the inlet 51, AC power from the external power source 200 (hereinafter also referred to as “external power”) is input to the inlet 51.

  The charger 50 is controlled by a control signal from the control device 100 and converts external power (AC power) input from the external power source 200 to the inlet 51 into power (DC power) that can be charged to the driving battery 10. Supply to high pressure system. As a result, the driving battery 10 is charged by the external power. Hereinafter, charging the driving battery 10 with external power is referred to as “external charging”.

  When the connector 201 of the external power source 200 is connected to the inlet 51, a control pilot signal (hereinafter referred to as “CPLT signal”) is input to the inlet 51 from the charging cable 202 of the external power source 200. The CPLT signal oscillates at a duty cycle corresponding to the current that can be supplied from the external power supply 200 to the vehicle 1. The CPLT signal is input to the control device 100 via the inlet 51.

  The vehicle 1 includes a monitoring unit 11 that detects the state of the driving battery 10, specifically, temperature (hereinafter also referred to as “battery temperature Tb”), current, voltage, and the like. Further, the vehicle 1 has a plurality of sensors (all of which are shown in FIG. 1) that detect information necessary for controlling the traveling of the vehicle 1, such as the state of the auxiliary battery 30 (voltage, current, temperature, etc.), the accelerator pedal position, and the vehicle speed. Not shown). Each sensor outputs a detection result to the control device 100.

  The timer 60 measures an elapsed time t from the start timing instructed from the control device 100 and outputs the measured elapsed time t to the control device 100. The timer 60 can be realized by, for example, an in-vehicle clock or a navigation device. In the example shown in FIG. 1, the timer 60 is provided outside the control device 100, but the timer 60 may be provided inside the control device 100.

  The control device 100 includes a CPU (Central Processing Unit) and a memory, and controls each device of the vehicle 1 according to information stored in the memory, detection results of each sensor, and the like. In FIG. 1, the control device 100 is a single unit, but may be divided for each function.

  When external power supply 200 is connected to inlet 51, control device 100 determines whether or not external charging is possible based on a CPLT signal from charging cable 202. When it is determined that external charging is possible, control device 100 operates charger 50 to start external charging. Control device 100 stops charger 50 and terminates external charging when the amount of power stored in drive battery 10 reaches a target value due to external charging.

  When the vehicle 1 having the above configuration is left in an extremely low temperature environment during external charging or after completion of external charging, the battery temperature Tb decreases and the output performance (output power) of the driving battery 10 decreases. It will be in the state. In such a state, even if the user tries to run the vehicle 1 next time, sufficient power cannot be supplied from the driving battery 10 to the motor, and there is a concern that the motor running performance deteriorates.

  In view of such a point, the control device 100 performs control (hereinafter also referred to as “temperature increase control”) for operating the heater 40 to raise the temperature of the driving battery 10 during external charging or after completion of external charging. . After the start of external charging, the external power source 200 is connected to the inlet 51 and the heater 40 can be operated using external power, so that the driving battery 10 does not decrease the amount of power stored in the driving battery 10. A temperature increase of 10 can be performed.

  However, it is also assumed that the vehicle 1 is left unused for a long period (for example, several tens of days or more). In such a case, if the temperature increase control is continued for a long time until the vehicle 1 is next used, the energy required for increasing the temperature of the drive battery 10 is wasted. On the other hand, if the period during which the temperature raising control is continued is a short period (for example, about several days), the electrolyte of the driving battery 10 is frozen even if the user tries to run the vehicle 1 after the temperature raising control is stopped. Thus, there is a risk that the drive battery 10 cannot be input / output at all and the vehicle 1 cannot be retreated.

  In view of the above problems, control device 100 according to the present embodiment divides a period during which temperature increase control is continued into a first period and a second period, and changes the target temperature for temperature increase in each period. The first period of the first half is defined as a period in which the user is relatively likely to use the vehicle 1, and the purpose is to guarantee a certain running performance (original motor running performance) by the motor from the start of running. And a relatively high target temperature. The second period in the latter half is defined as a period in which the user is relatively unlikely to use the vehicle 1, and is set to a minimum target temperature necessary for preventing the electrolyte solution of the driving battery 10 from freezing.

  FIG. 2 is a diagram illustrating an example of a change in the battery temperature Tb by the temperature increase control performed by the control device 100. In FIG. 2, the horizontal axis indicates the elapsed time t since the plug-in state (the external power source 200 is connected to the inlet 51 and external charging is possible), and the vertical axis indicates the battery temperature Tb.

  In FIG. 2, the period until the elapsed time t from the plug-in state becomes the time t1 is the first period. During the first period, control device 100 operates and stops heater 40 so as to maintain battery temperature Tb in target temperature region R1 between upper limit temperature T1 and lower limit temperature T2. More specifically, the control device 100 closes the switch 41 to operate the heater 40 when the battery temperature Tb falls to the lower limit temperature T2, and operates the switch 41 when the battery temperature Tb rises to the upper limit temperature T1 by the operation of the heater 40. Open and stop the heater 40. Hereinafter, the temperature increase control executed during the first period is also referred to as “first temperature increase control”.

  As described above, the target temperature region R1 during the first temperature rise control is set to a relatively high target temperature for the purpose of guaranteeing a constant running performance (original motor running performance) by the motor from the start of running. Is done. In other words, the target temperature region R1 during the first temperature increase control has a higher power than that when the battery temperature Tb is maintained in the target temperature region R2 (described later) during the second temperature increase control. This is the temperature range that can be output. Therefore, during the first period, vehicle travel can be started with a greater vehicle driving force than during the second period. That is, when the user uses the vehicle 1 during the first period, even if the outside air temperature is extremely low, the original motor running performance can be exhibited from the start of the vehicle running.

  In FIG. 2, the period from when the elapsed time t after the plug-in state is reached to time t1 until time t2 is the second period. During the second period, control device 100 operates and stops heater 40 to maintain battery temperature Tb in target temperature region R2 between upper limit temperature T3 and lower limit temperature T4. More specifically, the control device 100 closes the switch 41 when the battery temperature Tb falls to the lower limit temperature T4 and activates the heater 40. When the battery temperature Tb rises to the upper limit temperature T3 due to the operation of the heater 40, the control device 100 turns off the switch 41. Open and stop the heater 40. Hereinafter, the temperature increase control executed during the second period is also referred to as “second temperature increase control”.

  The lower limit temperature T4 of the target temperature region R2 during the second temperature increase control is lower than the lower limit temperature T2 of the target temperature region R1 during the first temperature increase control, and is lower than the temperature at which the electrolyte of the drive battery 10 freezes. Set to high temperature. In the present embodiment, a relational expression of T1> T2> T3> T4 is established between the temperatures T1 to T4 as shown in FIG. For example, a relational expression of T1> T3> T2> T4 may be established between the temperatures T1 to T4.

  Thus, even after the first period has elapsed, the upper limit temperature T3 of the battery temperature Tb is maintained at a temperature lower than the upper limit temperature T1 during the first period, and the lower limit temperature T4 of the battery temperature Tb is maintained during the first period. The heater 40 is continuously operated so as to be maintained at a temperature lower than the upper limit temperature T2 and higher than a temperature at which the electrolyte of the driving battery 10 freezes, thereby driving while suppressing an increase in power consumption of the heater 40. Freezing of the electrolyte solution of the battery 10 can be suppressed for a longer period. Therefore, when the user uses the vehicle 1 during the second period, even if the outside air temperature is extremely low, the electrolyte of the driving battery 10 is not frozen and the vehicle 1 is at least retracted. be able to.

  In the present embodiment, the second period is set to a period longer than the first period. For example, the first period can be set to several days, and the second period can be set to several tens of days. As described above, the second period in which the power consumption of the heater 40 is low is made longer than the first period in which the power consumption of the heater 40 is high, so that the increase in the power consumption of the heater 40 is suppressed and the electrolyte is frozen. It can be suppressed for a longer period.

  In addition, since it is assumed that the vehicle 1 is not used after the 2nd period passes, the control apparatus 100 stops temperature increase control (2nd temperature increase control). Thereby, it can suppress that the power consumption of the heater 40 increases uselessly.

  FIG. 3 is a flowchart showing a flow of processing when the control device 100 performs the temperature rise control. This flowchart is started when the plug-in state is entered (the external power source 200 is connected to the inlet 51 and external charging is possible).

  In step (hereinafter, step is abbreviated as “S”) 11, control device 100 outputs to timer 60 a command to start counting elapsed time t after the plug-in state is reached.

  In S <b> 12, control device 100 acquires elapsed time t from timer 60. In S13, control device 100 determines whether or not elapsed time t has exceeded time t1 (for example, about several days).

  If elapsed time t does not exceed time t1 (NO in S13), control device 100 sets target upper limit temperature High and target lower limit temperature Tlow to upper limit temperature T1 and lower limit temperature T2, respectively (see FIG. 2). ).

  When elapsed time t exceeds time t1 (YES in S13), control device 100 sets target upper limit temperature High and target lower limit temperature Tlow, and upper limit temperature T3 and lower limit temperature T4, respectively, in S15 (see FIG. 2). Set to.

  In S16, control device 100 acquires battery temperature Tb from monitoring unit 11. In S17, control device 100 switches operation (on) and stop (off) of heater 40 such that battery temperature Tb is maintained between target upper limit temperature High and target lower limit temperature Tlow. This process corresponds to temperature increase control (first temperature increase control or second temperature increase control).

  In S18, control device 100 determines whether or not elapsed time t has exceeded time t2 (for example, about several tens of days).

  When elapsed time t does not exceed time t2 (NO in S18), control device 100 returns the process to S12 and repeats the processes of S12 to S18.

  When elapsed time t exceeds time t2 (YES in S18), control device 100 shuts down the entire temperature raising system including itself. Thereby, the second temperature raising control is stopped.

  As described above, the control device 100 according to the present embodiment guarantees the original motor running performance for the battery temperature Tb during the first period until the elapsed time t from the plug-in state reaches the time t1. The first temperature increase control is performed to maintain the temperature range R1 within the possible range, and the battery temperature Tb is lower than the target temperature range R1 during the second period after the first period has elapsed, and the electrolyte of the driving battery 10 The second temperature rise control is performed to maintain the temperature region R2 higher than the temperature at which the water freezes. Thereby, freezing of the electrolyte solution of the drive battery 10 can be suppressed for a longer period while suppressing an increase in power consumption of the heater 40.

<Modification>
In the above-described embodiment, the temperature raising system including the control device 100 is maintained in the operating state during the temperature raising control (the first temperature raising control and the second temperature raising control).

  However, the temperature raising system may be intermittently stopped during the temperature raising control (the first temperature raising control and the second temperature raising control). For example, the control device 100 learns a change waveform of the outside air temperature, and the battery temperature Tb becomes the target lower limit temperature Tlow from the learning result of the outside air temperature change waveform and the outside air temperature when the battery temperature Tb reaches the target upper limit temperature High. It is also possible to predict the time when the temperature will decrease and to set the predicted time as the next system start time and then temporarily stop the temperature raising system. If it does in this way, energy required for temperature rise of drive battery 10 can be reduced more.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Vehicle, 10 Drive battery, 11 Monitoring unit, 20 DC / DC converter, 30 Auxiliary battery, 40 Heater, 41 Switch, 50 Charger, 51 Inlet, 60 Timer, 100 Control apparatus, 200 External power supply, 201 Connector, 202 Charging cable.

Claims (5)

A battery temperature increasing device that is mounted on a vehicle that can be connected to an external power source and configured to be rechargeable using electric power supplied from the external power source,
A heater for heating the battery from the outside;
A controller for performing a temperature rise control for heating the battery by heating the battery with the heater;
The controller is
During the period from when the external power source is able to supply power to the battery until the first period elapses, a first rise for controlling the heater so that the temperature of the battery is equal to or higher than a first lower limit temperature. Temperature control,
After the first period has elapsed, a second temperature increase control is performed to control the heater so that the temperature of the battery is equal to or higher than a second lower limit temperature,
The battery temperature raising device, wherein the second lower limit temperature is lower than the first lower limit temperature and higher than a temperature at which the electrolyte of the battery freezes. The vehicle generates vehicle driving force by operating a motor using electric power of the battery,
2. The temperature rise of the battery according to claim 1, wherein the first lower limit temperature is a temperature at which the battery can output higher power to the motor than when the temperature of the battery is the second lower limit temperature. apparatus.   3. The battery temperature rising device according to claim 1, wherein the control device stops the second temperature rising control when a second period has elapsed since the start of the second temperature rising control. 4.   The battery temperature increasing device according to claim 3, wherein the second period is longer than the first period. The first temperature increase control is a control for operating and stopping the heater so as to maintain the temperature of the battery in a first temperature region that is equal to or higher than the first lower limit temperature and lower than the first upper limit temperature.
The second temperature increase control is a control for operating and stopping the heater so as to maintain the temperature of the battery in a second temperature region that is equal to or higher than the second lower limit temperature and lower than the second upper limit temperature.
The battery temperature increasing device according to claim 1, wherein the second upper limit temperature is lower than the first upper limit temperature.

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