JP6402687B2 - Vehicle battery system - Google Patents

Description

  The present invention relates to a vehicle battery system mounted on a vehicle.

  2. Description of the Related Art Conventionally, electric vehicles that use a rotating electric machine as one of the power sources, such as hybrid vehicles and electric vehicles, are widely known. Such an electric vehicle is equipped with a battery for supplying electric power to the rotating electrical machine. The in-vehicle battery is a secondary battery that can be charged and discharged, and can charge electric power generated by a rotating electrical machine and electric power from an external power source. Such an in-vehicle battery has a longer charging time due to a decrease in chargeable capacity and a decrease in allowable charging current when the temperature is lowered. Moreover, when the vehicle-mounted battery falls to the freezing temperature, there is a characteristic that charging and discharging cannot be performed.

  Here, an electric vehicle may be in the plug-in connection state which connects a vehicle-mounted battery and an external power supply for a charge after a stop. At this time, if the environmental temperature is low, the battery temperature also decreases with time, and there is a problem that charging from an external power source cannot be performed appropriately. Therefore, in some cases, it has been proposed to raise the temperature of the in-vehicle battery with a heater so that the temperature of the in-vehicle battery is equal to or higher than a reference value in the plug-in connection state. At this time, a system is disclosed in which charging control for terminating charging of the in-vehicle battery is completed by a user set time set by the user and temperature increase control for increasing the temperature of the in-vehicle battery is disclosed (Patent Document 1).

JP 2014-207723 A

  By the way, in a vehicle placed in an external environment where the temperature of the in-vehicle battery needs to be raised, the vehicle window may freeze. When the vehicle window freezes, even if the in-vehicle battery has been charged by the user-set time and the in-vehicle battery has reached a temperature at which it can run, the vehicle cannot be run immediately due to the freezing of the window, and has adhered to the window. Work to melt ice is required.

  One aspect of the present invention includes a battery for supplying driving power to a vehicle, anti-freezing control means for preventing the vehicle window from freezing, and charging power that is variable when the battery is less than a predetermined voltage. A first charging control period for charging and a second charging control period for charging the battery with a constant charging power when the battery is equal to or higher than a predetermined voltage are set by the user by charging the battery. Charging control means for performing charge control so that charging of the battery is completed at a user set time, and the freeze prevention control means freezes the window by the user set time in the second charge control period. If not expected, the window is frozen during the first charge control period, and the window is frozen before the user set time during the second charge control period. If it is expected it is a vehicle battery system and performs processing to prevent freezing of the window at the second charging control period.

  According to the present invention, it is possible to immediately run the vehicle at the user set time set by the user by terminating the charging of the battery and preventing the vehicle window from freezing.

It is a figure which shows schematic structure of the hybrid drive system which is embodiment of this invention. It is a timing chart explaining charge control in an embodiment of the invention. It is a flowchart which shows the freeze prevention control in embodiment of this invention. It is a figure which shows the example of registration of the freezing database in embodiment of this invention. It is a figure which shows the example of registration of the melting database in embodiment of this invention. It is a timing chart explaining the freeze prevention process in embodiment of this invention. It is a timing chart explaining the freeze prevention process in embodiment of this invention. It is a timing chart explaining the freeze prevention process in embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a hybrid drive system 10 according to an embodiment of the present invention. This hybrid drive system 10 is provided with two rotating electrical machines MG1 and MG2 and one engine 12 as power sources. The hybrid drive system 10 is provided with a main battery 20 that supplies electric power to the rotating electric machines MG1 and MG2 or stores electric power generated by the rotating electric machines MG1 and MG2. The main battery 20 has a plurality of single cells connected in series. As the single battery, a secondary battery such as a nickel metal hydride battery or a lithium ion battery can be used. In addition, an electric double layer capacitor can be used instead of the secondary battery. The main battery 20 may include a plurality of single cells connected in parallel.

  The voltage value VB of the main battery 20 is detected by the voltage sensor 22 and input to the controller 26. The current value IB of the current of the main battery 20 is detected by the current sensor 23 and input to the controller 26. A temperature sensor 24 for detecting the temperature of the main battery 20 (battery temperature Tb) is also provided in the vicinity of the main battery 20. The temperature sensor 24 functions as a battery temperature acquisition unit that acquires the battery temperature Tb. The battery temperature Tb detected by the temperature sensor 24 is input to the controller 26.

  In addition, a temperature sensor 25 that measures an environmental temperature Ta, which is the temperature of the environment in which the main battery 20 is installed, is provided in order to perform a temperature raising operation that will be described later. The temperature sensor 25 measures the environmental temperature Ta in the external environment of the vehicle in which the hybrid drive system 10 is provided, and outputs the measured environmental temperature Ta to the controller 26. For example, the temperature sensor 25 may be provided outside the passenger compartment or in the refrigerant intake path for cooling the main battery 20.

  The main battery 20 is connected to the inverter 18 via the system main relay 44. When the ignition switch of the vehicle is switched from OFF to ON, the controller 26 electrically connects the main battery 20 and the inverter 18 by switching these system main relays 44 from OFF to ON. Conversely, when the ignition switch of the vehicle is switched from on to off, the controller 26 electrically disconnects the main battery 20 and the inverter 18 by switching these system main relays 44 from on to off.

  The inverter 18 converts the DC power supplied from the main battery 20 into AC power and outputs the AC power to the second rotating electrical machine MG2. The second rotating electrical machine MG2 receives the AC power output from the inverter 18 and generates kinetic energy for running the vehicle. The kinetic energy generated by the second rotating electrical machine MG2 is transmitted to the drive wheels 16 so that the vehicle travels. The second rotating electrical machine MG2 converts kinetic energy generated during braking of the vehicle into electrical energy. The inverter 18 converts AC power (regenerative power) generated by the second rotating electrical machine MG2 into DC power and supplies it to the main battery 20. Thereby, the main battery 20 is charged.

  The power split mechanism 14 transmits the power of the engine 12 to the drive wheels 16 or to the first rotating electrical machine MG1. First rotating electrical machine MG1 receives power from engine 12 to generate power. The electric power generated by the first rotating electrical machine MG1 is supplied to the second rotating electrical machine MG2 via the inverter 18 or supplied to the main battery 20. The main battery 20 is charged by supplying power to the main battery 20.

  A booster circuit (not shown) is also provided in the current path between the main battery 20 and the inverter 18. The booster circuit boosts the output voltage of the main battery 20 and outputs the boosted power to the inverter 18. The booster circuit steps down the output voltage of the inverter 18 and outputs the reduced power to the main battery 20.

  A DC / DC converter 30 is also connected to the main battery 20. The DC / DC converter 30 is connected in parallel with the inverter 18. An auxiliary machine 36, an auxiliary battery 34, and a heater 32 are connected to the DC / DC converter 30. The DC / DC converter 30 steps down the output voltage of the main battery 20 and supplies the reduced power to the auxiliary machine 36 and the auxiliary battery 34. Thereby, the auxiliary machine 36 can be operated and the auxiliary machine battery 34 can be charged. The operation of the DC / DC converter 30 is controlled by the controller 26.

  The heater 32 is used to raise the temperature of the main battery 20. The heater 32 is provided in the vicinity of the main battery 20. Further, the heater 32 may be one or plural. A switch 46 is provided in the current path between the DC / DC converter 30 and the heater 32. The switch 46 receives a control signal from the controller 26 and electrically connects or disconnects the DC / DC converter 30 and the heater 32. When the switch 46 is turned on, predetermined power is supplied from the DC / DC converter 30 to the heater 32, and the heater 32 can generate heat. And when the heater 32 generates heat, the main battery 20 is heated. The heater 32 is controlled by the controller 26. That is, the battery temperature raising means for raising the temperature of the main battery 20 is configured by the heater 32, the temperature sensor 24, the controller 26, and the like.

  The auxiliary machine 36 includes an air conditioner (A / C) 36a. By operating the air conditioner 36a, the temperature in the passenger compartment of the vehicle in which the hybrid drive system 10 is provided can be adjusted. In addition to the use of the air conditioner 36a, the interior of the vehicle compartment may be heated using heat from the heater 32 or exhaust heat from the main battery 20. Thereby, when the window of a vehicle freezes, the adhering ice can be thawed and the window can be prevented from freezing in advance. That is, the heater 32, the air conditioner 36a, the controller 26, and the like constitute a freeze prevention control means for preventing the window from freezing.

  A charger 38 is further connected to the main battery 20. A charging relay 42 is provided between the main battery 20 and the charger 38. The charge relay 42 receives a control signal from the controller 26 and electrically connects or disconnects the charger 38 and the main battery 20. A connector 40 (inlet) is connected to the charger 38. A connector 102 (charging plug) of an external power supply 100 (for example, commercial power supply) can be connected to the connector 40. The controller 26 monitors whether the two connectors 40 and 102 are connected, that is, whether the two connectors 40 and 102 are plugged in or the two connectors 40 and 102 are disconnected.

  When connector 40 is connected to connector 102 and charging relay 42 is on, charger 38 converts AC power from external power supply 100 into DC power and outputs DC power. The operations of the charger 38 and the charging relay 42 are controlled by the controller 26. The DC power output from the charger 38 is supplied to the main battery 20, thereby charging the main battery 20. Hereinafter, charging the main battery 20 using the power from the external power supply 100 is referred to as “external charging”.

  In the hybrid vehicle, external charging is possible while the vehicle is stopped, but the user can set the end time of the external charging as the user set time tx. That is, the user can set the user set time tx so that charging of the main battery 20 will be completed by considering the time when the vehicle is scheduled to be used next.

  The controller 26 controls charging of the main battery 20 by external charging. The controller 26 receives the voltage value VB of the main battery 20 from the voltage sensor 22 and controls the charging power supplied to the main battery 20 from the relationship between the voltage value VB and a predetermined reference voltage. As shown in FIG. 2, when the voltage value VB is less than a predetermined reference voltage, the controller 26 sets the first charge control CP1 that the power supplied to the main battery 20 may change with time, and the voltage value VB. Is equal to or higher than a predetermined reference voltage, the second charge control CP2 is set to keep the power supplied to the main battery 20 as constant as possible. In the first charge control CP1, the main battery 20 can be charged rapidly, and in the second charge control CP2, the main battery 20 can be more fully charged due to effects such as push-in charging.

  As shown in FIG. 2, the controller 26 sets the charging start time t0 of the main battery 20 so that the charging of the main battery 20 is completed at the user set time tx. That is, the time before the user setting time tx by the period T1 of the first charging control CP1 and the period T2 of the second charging control CP2 is set as the charging start time t0. Then, the controller 26 starts charging the main battery 20 from the charging start time t0. The controller 26 estimates the period T1 of the first charging control CP1 and the period T2 for performing the second charging control CP2 from conditions such as the battery temperature Tb of the main battery 20 and the current charging state Soc. Since the battery temperature Tb and the like of the main battery 20 change from moment to moment, the controller 26 estimates and updates the periods T1 and T2 as needed until charge control is started, and the charge start time t0 is set at an appropriate time as possible. It may be set.

  In the plug-in state, the power from the charger 38 can be supplied not only to the main battery 20 but also to the DC / DC converter 30. Here, when the switch 46 is turned on, the DC / DC converter 30 can step down the electric power from the charger 38 and supply the electric power after the step down to the heater 32. That is, in the plug-in state, the main battery 20 can be heated by driving the heater 32 using a part of the electric power from the external power supply 100.

The main battery 20 has a characteristic that when the temperature is lowered, the charging time becomes longer due to a decrease in chargeable capacity and a decrease in allowable charge amount. Moreover, when the temperature of the main battery 20 falls too much, there exists a possibility that charging / discharging cannot be performed. Therefore, even after the vehicle is stopped, in the plug-in state, the controller 26 performs the temperature increasing operation of the main battery 20 by the heater 32. When the user set time tx is set, the controller 26 uses the heater 32 at the user set time tx to control the temperature increase so that the battery temperature Tb of the main battery 20 becomes equal to or higher than the set battery temperature lower limit value Tb _min. I do. Further, when the vehicle is not used after the user set time tx has elapsed, the controller 26 intermittently moves the main battery 20 using the heater 32 for a certain period of time so that the temperature of the main battery 20 does not decrease. Temperature rise control.

  In hybrid drive system 10 in the present embodiment, charging of main battery 20 is completed at user set time tx, and anti-freezing control is performed to keep the vehicle window free from freezing. Hereinafter, the freeze prevention control process will be described with reference to the flowchart of FIG.

  When charging control is started in the external charging state by plug-in, the controller 26 starts anti-freezing control.

  In step S10, it is determined whether or not the current time exceeds the user set time tx. If the current time is less than the user set time tx, the controller 26 shifts the process to step S12 to perform temperature increase control, and if the current time is greater than or equal to the user set time tx, the controller 26 performs process to perform intermittent temperature increase control. To step S22.

  In step S12, it is determined whether or not the period T2 is equal to or longer than the time tim2 until the vehicle window freezes. The time tim2 until the vehicle window freezes is the time until the window freezes from the state where the vehicle window is not frozen at all. The time tim2 changes according to the temperature of the environment in which the vehicle is placed, that is, the environmental temperature Ta measured by the temperature sensor 25. Therefore, as shown in FIG. 4, the relationship between the environmental temperature Ta and the time tim2 until the window is frozen is examined in advance and registered in the memory 28 as a frozen database. The controller 26 reads the time tim2 corresponding to the environmental temperature Ta input from the temperature sensor 25 with reference to the freezing database.

  Then, the controller 26 shifts the process to step S14 if the period T2 is less than the time tim2, and shifts the process to step S18 if the period T2 is equal to or greater than the time tim2. The period T2 being less than the time tim2 indicates that the second charge control is performed if the process of melting the freezing of the window is terminated at the start time of the second charge control CP2 (that is, the end time of the first charge control CP1). This means that there is no possibility that the window will freeze again during the period T2 during which CP2 is performed. Therefore, the process is shifted to step S14, and the window freeze prevention control is performed in the period T1 of the first charging control CP1. On the other hand, the period T2 is equal to or greater than the time tim2 even if the process of melting the freezing of the window at the start time of the second charge control CP2 (that is, the end time of the first charge control CP1) is terminated. This means that the window may freeze again during the period T2 during which the charging control CP2 is performed. Therefore, the process proceeds to step S18, and the window freeze prevention control is performed during the period T2 of the second charge control CP2.

  In step S14, it is determined whether or not the remaining time obtained by subtracting the current time from the start time of the second charge control CP2 is larger than the time tim1 necessary for melting the frozen ice on the window. The time tim1 required for melting the frozen window ice varies depending on the temperature of the environment in which the vehicle is placed, that is, the ambient temperature Ta measured by the temperature sensor 25. Therefore, as shown in FIG. 5, the relationship between the environmental temperature Ta and the time tim1 required for melting is investigated in advance and registered in the memory 28 as a melting database. The controller 26 reads the time tim1 corresponding to the environmental temperature Ta input from the temperature sensor 25 with reference to the melting database. The controller 26 stands by until the remaining time obtained by subtracting the current time from the start time of the second charge control CP2 reaches a time tim1 for melting the frozen ice on the window, and from the start time of the second charge control CP2. When the remaining time after subtracting the time reaches the time tim1 for thawing the frozen ice on the window, the process proceeds to step S16.

  In step S16, the frozen window ice is thawed. As shown in FIG. 6, the controller 26 becomes the time tim1 necessary for melting the ice of the frozen window, which is the remaining time obtained by subtracting the current time from the start time of the second charge control CP2, that is, the second When the time before the time tim1 comes from the start time of the charging control CP2, the melting process is started. The controller 26 operates the air conditioner 36a to increase the in-vehicle temperature of the vehicle on which the hybrid drive system 10 is mounted. At this time, it is preferable to use the exhaust heat in the temperature rise control of the main battery 20 by the heater 32 together with the use of the air conditioner 36a. The melting process is performed for a time tim1. After the melting process, it is determined in step S26 whether or not the vehicle has been restarted. If the vehicle has been restarted, the freeze prevention control is terminated, and if not, the process returns to step S10.

  As a result of the process in step S16, the ice in the window frozen up to the start time of the second charge control CP2 is melted. Further, since the period T2 of the second charging control CP2 is shorter than the time tim2 until the window is frozen again, the window is not frozen when the user set time tx is reached. Therefore, it is possible to prevent the window from being frozen when the vehicle is restarted at the user set time tx, and the user can use the vehicle smoothly.

  In step S18, it is determined whether or not the remaining time obtained by subtracting the current time from the user set time tx is greater than the time tim1 necessary for thawing the frozen window ice. The controller 26 reads the time tim1 corresponding to the environmental temperature Ta input from the temperature sensor 25 with reference to the melting database. The controller 26 waits until the remaining time obtained by subtracting the current time from the user set time tx reaches a time tim1 necessary for thawing the frozen window ice, and the remaining time obtained by subtracting the current time from the user set time tx. When the time tim1 necessary for thawing the frozen ice on the window is reached, the process proceeds to step S20.

  In step S20, the frozen window ice is thawed. As shown in FIG. 7, the controller 26 obtains the time tim1 necessary for melting the frozen ice of the frozen window by subtracting the current time from the user set time tx, that is, the time tim1 from the user set time tx. The melting process is started only at the previous time. The controller 26 operates the air conditioner 36a to increase the in-vehicle temperature of the vehicle on which the hybrid drive system 10 is mounted. At this time, it is preferable to use the exhaust heat in the temperature rise control of the main battery 20 by the heater 32 together with the use of the air conditioner 36a. The melting process is performed for a time tim1. After the melting process, it is determined in step S26 whether or not the vehicle has been restarted. If the vehicle has been restarted, the freeze prevention control is terminated, and if not, the process returns to step S10.

  By the processing in step S20, the window ice is melted at the user set time tx. Therefore, it is possible to prevent the window from being frozen when the vehicle is restarted at the user set time tx, and the user can use the vehicle smoothly.

  In step S12, by determining whether or not the period T2 of the second charge control CP2 is equal to or longer than the time tim2 until the vehicle window freezes, the freezing is performed in the period T2 of the second charge control CP2. If there is no fear, the freeze prevention process can be performed in the period T1 of the first charge control CP1. That is, it is possible to make the window not frozen at the user set time tx while avoiding the freeze prevention process in the period T2 of the second charge control CP2 in which the main battery 20 needs to be charged with constant power.

  In steps S22 and S24, intermittent temperature increase control after the user set time tx is performed. In step S22, it is determined whether or not the elapsed time T3 from the time when the previous window ice melting process is completed is equal to or longer than the time tim2 until the vehicle window freezes. The controller 26 reads the time tim2 at the environmental temperature Ta input from the temperature sensor 25 with reference to the freezing database. If the elapsed time T3 is equal to or longer than the time tim2 until the vehicle window freezes, the controller 26 shifts the process to S24, and if not, shifts the process to step S26.

  In step S24, the frozen window ice is thawed. The controller 26 begins the process of thawing frozen window ice. The controller 26 reads the time tim1 at the environmental temperature Ta input from the temperature sensor 25 with reference to the melting database. Then, the controller 26 performs the melting process for the time tim1. As a result, as shown in FIG. 8, the melting process is performed for the time tim1 every time tim2 from the time when the previous melting process is completed until the window is frozen. In step S26, it is determined whether or not the vehicle has been restarted. If the vehicle has been restarted, the freeze prevention control is terminated; otherwise, the process returns to step S10.

  The configurations described so far are only examples, and any configuration can be used as long as the window is not frozen at the user set time tx. For example, in the present embodiment, the environmental temperature Ta of the vehicle is measured using the temperature sensor 25, but the environmental temperature Ta may be estimated from the battery temperature Tb. In the present embodiment, a hybrid vehicle has been described as an example. However, the scope of application of the present invention is not limited to a hybrid vehicle, and any other vehicle such as an electric vehicle may be used as long as the vehicle (including a fuel cell) is mounted. Or a fuel cell vehicle.

  10 hybrid drive system, 12 engine, 14 power split mechanism, 16 drive wheels, 18 inverter, 20 main battery, 22 voltage sensor, 23 current sensor, 24, 25 temperature sensor, 26 controller, 28 memory, 30 DC / DC converter, 32 heater, 34 auxiliary battery, 36 auxiliary machine, 36a air conditioner, 38 charger, 40,102 connector, 42,44 relay, 46 switch, 100 external power supply, MG1, MG2 rotating electrical machine.

Claims (1)

A battery for supplying driving power to the vehicle;
Anti-freezing control means for preventing the vehicle window from freezing;
A first charging control period for charging the battery with variable charging power when the battery is less than a predetermined voltage, and a second charging for charging the battery with constant charging power when the battery is equal to or higher than a predetermined voltage. Charging control means for charging the battery in a charging control period, and charging control so that charging of the battery is completed at a user set time set by the user,
With
The freeze prevention control means uses the power from the battery in the first charge control period when the window is not expected to freeze by the user set time in the second charge control period. If the window is expected to freeze by the user set time in the second charge control period, power from the battery is used in the second charge control period. The vehicle battery system is characterized by performing a process for preventing the window from freezing.

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