JP2021118629A - Vehicle battery control device - Google Patents

Abstract

To provide a vehicle battery control device that can prevent battery deterioration while meeting the requirements of fail-safe design.SOLUTION: A battery control device 1 includes a battery 20 that supplies electric power to a motor 11 that drives a vehicle 10, an in-vehicle charger (charge control unit) 17 for supplying electric power supplied from an external power supply device 100 to the battery, a main contactor unit 22a (switch unit) for connecting and disconnecting the battery and the charge control unit, a switch control unit 51 for controlling the switch unit, a heater 40 connected to the charge control unit for increasing the temperature of the battery, a heater control unit 52 for controlling the energization of the heater, and a limiting resistor unit 28 that has an impedance higher than the impedance of the heater. The switch control unit controls the switch unit such that the limiting resistor unit is connected in series with the battery when the heater control unit determines that the heater is energized at the time of charging the battery from the external power supply device.SELECTED DRAWING: Figure 2

Description

The present invention relates to a vehicle battery control device, and more particularly to a vehicle battery control device that controls charging using electric power of an external power supply device in an extremely low temperature environment.

Batteries such as lithium ion batteries and nickel-metal hydride batteries are known as drive batteries mounted on electric vehicles such as electric vehicles and hybrid vehicles.

Such a battery is known to have problems in an extremely low temperature environment. For example, when a lithium-ion battery is energized by charging and discharging in an extremely low temperature environment of about -10 to -30 degrees Celsius, lithium metal is likely to precipitate, which accelerates battery deterioration and increases the risk of short circuit. do.

In consideration of such a problem, for example, in Patent Document 1, when the drive battery is charged in an extremely low temperature environment, the drive battery is supplied from an external charging device or the like after the main contactor of the drive battery is turned off. A technique is disclosed in which a heater is driven by electric power, and when the driving battery reaches a predetermined temperature or higher, the main contactor is turned on and charging is started.

JP-A-2015-47027

However, in recent years, in such a charging system, from the viewpoint of fail-safe design, it has been required to turn on the main contactor of the drive battery when a high voltage charging power is supplied from the outside into the vehicle. There is.

Specifically, even when the heater is driven to raise the temperature of the battery by the electric power supplied from the external charging device, for example, when an ignition occurs due to a short circuit on the high voltage circuit, the drive battery is appropriately discharged. It is necessary to turn on the main contactor in order to operate the safety device such as the fire extinguishing device.

On the other hand, when the main contactor of the drive battery is turned on, the internal resistance value of the battery in an extremely low temperature environment is lower than the resistance value of the heater, so the power supplied from the external power supply device is not only the heater but also a certain amount. It is also supplied to the drive battery. Therefore, as a result, there is a risk of increasing the risk of short circuit in the battery and deteriorating the battery.

From the above, the problem to be solved in the present application is that the vehicle can prevent the risk of short circuit of the drive battery from increasing and deterioration while satisfying the requirement of fail-safe design when the charging power is supplied to the battery of the vehicle from the outside. The purpose is to provide a battery control device.

The present invention has been made to solve at least a part of the above-mentioned problems, and can be realized as the following aspects or application examples.

(1) The vehicle battery control device according to the present application example includes a battery for supplying electric power to a motor for driving the vehicle, and a charge control unit for supplying electric power supplied from an external power supply device to the battery. , A switch unit for connecting and disconnecting the battery and the charge control unit, a switch control unit for controlling the connection and disconnection of the switch unit, and a charge control unit for connecting and raising the temperature of the battery. The heater control unit includes a heater, a heater control unit for controlling energization of the heater, and a limiting resistance unit having an impedance higher than the impedance of the heater, and the heater control unit charges the battery from the external power supply device. When it is determined that the heater is energized, the switch control unit controls the switch unit so that the limiting resistance unit is connected in series with the battery.

That is, according to the vehicle battery control device according to the above application example, when the battery is charged from the external power supply device, the electric power of the external power supply device is applied to the heater to raise the temperature of the battery, and the battery is heated according to the request of fail-safe. If the second switch is made conductive in the switch unit that connects the battery and the external power supply device, a resistance larger than the resistance value of the heater is provided in series with the battery. This limits the flow of current from the external power supply into the battery while meeting the requirements of a fail-safe design, preventing increased risk of short circuit and deterioration of the battery, and allowing more current to flow to the heater. As a result, the temperature of the battery can be raised quickly.

(2) In the vehicle battery control device according to the above application example, in the above (1), the impedance value Z _limit of the limiting resistor portion is the impedance value Z _heater of the heater and the current value I _{heater flowing into the heater.} The relationship between and the minimum current value I _{min flowing into the battery is}
Z _heater × I _heater / I _min <Z _limit
It may have a value such as. As a result, in the system design, by setting the minimum current value I _min flowing into the battery 20 to a value capable of suppressing battery deterioration, the current value I _heater flowing into the heater 40 and the impedance value Z _{heater of the heater 40} Therefore, the minimum value of the _{impedance value Z limit} of the limiting resistance unit 28 can be determined.

(3) In the vehicle battery control device according to the above application example, in the above (1) or (2), the switch unit is configured in parallel with the first path including the first switch and the first path. When the heater control unit energizes the heater when charging the battery from the external power supply device, the heater control unit includes a second path including a second switch connected in series with the limiting resistance unit. When determining, the switch control unit may perform control in which the first switch is disconnected and the second switch is in contact. As a result, the limiting resistor can be added only when it is necessary to add it.

(4) The vehicle battery control device according to the above application example further includes a temperature sensor for detecting the temperature of the battery in any of the above (1) to (3), and the heater control unit is the temperature sensor. It may be determined whether or not to energize the heater based on the information from. As a result, it is possible to limit the inflow of current from the external power supply device to the battery in an extremely low temperature environment in which the battery is likely to deteriorate, and it is possible to suppress the risk of short circuit and deterioration in the battery.

(5) In the vehicle battery control device according to the above application example, in the above (4), the switch control unit may perform control to change the impedance of the limiting resistor unit based on the information of the temperature sensor. .. Specifically, the impedance of the limiting resistor is increased or decreased according to the rise or fall of the battery temperature to increase or decrease the inflow current to the battery. As a result, charging can be performed while the temperature of the battery is rising, and the time from the start of raising the temperature to the end of charging can be shortened. As a result, the energy received from the external power supply device can be efficiently used.

(6) The vehicle battery control device according to the above application example may include a variable resistor in any of the above (1) to (5). As a result, as the battery temperature rises, the resistance value of the limiting resistance portion can be reduced to increase the charging current to the battery, so that the same effect as in (5) above can be obtained.

(7) In any of (4) to (6) subordinate to the above (3) or (3), the vehicle battery control device according to the above application example has the limiting resistance portion as a resistor and the resistance. The switch control unit may control to change the opening / closing speed of the third switch while the switch control unit is in contact with the second switch, including a third switch connected in parallel to the body. As a result, the distribution of the time when the limiting resistor is added to the battery circuit and the time when the limiting resistor is not added can be changed according to the change in the battery temperature. That is, since the current limit amount can be changed over time, for example, when the battery temperature rises, the current limit amount can be reduced. As a result, the same effect as in (4) above can be obtained.

(8) In any of the above (1) to (7), the vehicle battery control device according to the above application example may be provided with the limiting resistor portion on the positive electrode side of the battery. Thereby, the inrush current can be relaxed.

It is an overall block diagram including the battery control device of the vehicle which concerns on one Embodiment of this invention. It is a circuit diagram of the battery control device of the vehicle which concerns on one Embodiment of this invention. It is a flowchart which shows the control routine executed by the control part of the battery control device of the vehicle which concerns on one Embodiment of this invention. It is a figure which shows the 1st modification of the limiting resistance part of FIG. It is a figure which shows the 2nd modification of the limiting resistance part of FIG.

Hereinafter, an embodiment embodying the present invention will be described.

FIG. 1 shows a schematic configuration diagram of a vehicle 10 including a battery control device 1 according to an embodiment of the present invention.

The vehicle 10 shown in FIG. 1 is, for example, an electric truck, and is equipped with a traveling motor 11 (hereinafter referred to as a motor 11) as a power source. The output shaft of the motor 11 is connected to the left and right drive wheels 14 via a power transmission unit 12 and a drive shaft 13 composed of a speed reducer and a differential device.

Further, the motor 11 is electrically connected to a high voltage drive battery (hereinafter referred to as a battery) 20 via an inverter converter (hereinafter, simply referred to as an inverter 15) 15 and a junction box 16.

The battery 20 converts the stored DC power into AC power via the inverter 15 and supplies it to the motor 11. Then, the driving force generated by the motor 11 is transmitted to the driving wheels 14 to drive the vehicle 10. Further, for example, when the vehicle 10 is decelerating or traveling on a downhill road (regenerative traveling), the motor 11 operates as a generator by the reverse driving force from the drive wheel 14 side (regenerative operation). The motor 11 functions as a generator by being rotated by the input reverse driving force. The AC power generated by the motor 11 is converted into DC power by the inverter 15 and charged into the battery 20 via the junction box 16. Further, when the motor 11 functions as a generator, resistance to the input reverse driving force is generated, so that a braking force is generated on the driving wheels 14.

The battery 20 is a secondary battery such as a lithium ion battery. Lithium-ion batteries have a predetermined operating temperature range suitable for exhibiting performance as a characteristic. Although the battery 20 is shown as a single block in FIG. 1, it is actually configured by connecting a plurality of cells in series or in parallel. Further, the battery 20 is provided with a service plug MSD (Manual Service Disconnect) having a mechanism capable of physically blocking and removing the power supply circuit to prevent electric shock during inspection or service.

The junction box 16 has a function of connecting the battery 20 and various electric devices mounted on the vehicle 10. Inside the junction box 16, an electric circuit for electrically connecting the battery 20 and various electric devices and switches such as various contactors (electromagnetic contacts) and relays for connecting and disconnecting the electric circuit are provided, and the switch is provided. It is possible to control the supply and disconnection of electric power from the battery 20 to various electric devices by connecting and disconnecting the batteries.

The in-vehicle charger 17 (charge control unit) includes a filter, a power conversion circuit, and a relay (not shown), converts the power input from the external power supply device 100 into a voltage suitable for charging the battery 20, and supplies the battery 20 with a voltage suitable for charging the battery 20. Has a function.

The external power supply device 100 is a facility for supplying electric power to the vehicle 10. For example, a normal charging device using 100V or 200V for home use, a quick charging device such as a charging stand, a non-contact charging device, or the like. The vehicle 10 can charge the battery 20 by receiving electric power from the external power supply device 100. As shown in FIG. 1, the in-vehicle charger is formed by engaging the power receiving terminal 30 formed in the vehicle 10 connected to the in-vehicle charger 17 with the power supply terminal (connector) 101 connected to the external power supply device 100. 17 can be connected to the external power supply device 100. The battery 20 can be charged by the electric power supplied from the external power supply device 100 by being connected to the external power supply device 100 via the junction box 16 and the vehicle-mounted charger 17.

The heater 40 is an element having a predetermined resistance value R _heater , and generates heat when receiving electric power. The heater 40 is arranged close to the battery 20 in order to raise the temperature of the battery 20. The heater 40 is, for example, a PTC (Positive Temperature Coefficient) heater. As the PTC heater, a heater having a resistance value of 32Ω can be used. Although the heater 40 uses a PTC heater in the present embodiment, another element that is supplied with electric power to generate heat may be used.

The heater circuit 43 is a circuit for connecting the heater 40 to the vehicle-mounted charger 17 via the junction box 16. Therefore, in a state where the battery 20 can be charged from the external power supply device 100, the heater 40 can be energized by using the electric power of the external power supply device 100 to generate heat.

The vehicle control unit 50 (hereinafter referred to as ECU 50) is a control unit including a central processing unit (CPU), a storage device (ROM, RAM, etc.) used for storing control programs, control maps, etc., an input / output device, a timer counter, and the like. Is. The ECU 50 is connected so as to communicate information with various devices and other control units mounted on the vehicle 10 and to perform control via the Control Area Network 60 (hereinafter referred to as CAN60), which is an in-vehicle communication network. There is. The ECU 50 of the present embodiment is a control unit that mainly monitors the state of the battery 20 and controls charging, temperature rise, etc., but the vehicle 10 is also provided with various ECUs. May be good.

FIG. 2 is a circuit diagram of the battery control device 1 of the vehicle 10 according to the present embodiment, and the circuit configuration of the battery control device 1 will be described below with reference to this figure.

As shown in FIG. 2, the battery 20 and the vehicle-mounted charger 17 are connected by a positive electrode side electric circuit BLP21a and a negative electrode side electric circuit BLN21b to form a battery circuit 27. The positive electrode side electric circuit BLP21a is provided with a positive electrode side main contactor portion 22a (switch portion) in the middle of the electric circuit. The negative electrode side electric circuit BLN21b is provided with a negative electrode side main contactor portion 22b in the middle of the electric circuit. The positive electrode side main contactor portion 22a (switch portion) includes a first electric circuit 24a (first path) including a positive electrode side main relay 23a (first switch), a heat mode relay 25 (second switch), and a first resistor. Three electric circuits, a second electric circuit 24b (second path) in which R1 (restrictive resistance portion 28) is connected in series, and a third electric circuit 24c in which the precharge relay 26 and the second resistor R2 are connected in series. Are connected in parallel. Further, a negative electrode side main relay 23b is inserted into the negative electrode side main contactor portion 22b.

When the external power supply device 100 is connected to the vehicle-mounted charger 17 to charge the battery 20, by connecting both the relay of the positive electrode side main contactor portion 22a and the negative electrode side main relay 23b, the external power supply device 100 is connected. The battery 20 conducts with the external power supply device 100 via the vehicle-mounted charger 17, and power is supplied to the battery 20 from the external power supply device 100 to charge the battery 20. The positive electrode side electric circuit BLP21a and the negative electrode side electric circuit BLN21b are taken over from the positive electrode and the negative electrode of the battery 20 to the circuit in the junction box 16, and the circuits and the switches including the positive electrode side main contactor portion 22a and the negative electrode side main contactor portion 22b are junctions. It is mounted as a substrate in the box 16.

Further, the disconnection and disconnection of each relay in the junction box 16 including the positive electrode side main contactor unit 22a (switch unit) is controlled by a signal from the switch control unit 51.

As shown in FIG. 2, the positive electrode side electric circuit BLP21a and the negative electrode side electric circuit BLN21b are connected by branching the on-vehicle charger 17, the inverter 15, the heater circuit 43, etc. at the same potential at the branch point X on the positive electrode side and the branch point Y on the negative electrode side. Will be done.

The limiting resistance portion 28 of the second electric circuit 24b in the present embodiment is a first resistor R1 made of a fixed resistor. The first resistor R1 has a _{resistance value R limit} larger than the resistance value R _heater of the heater 40. That is, in the present embodiment, the limiting resistor portion 28 has an impedance value Z _{limit higher than the impedance value Z heater} of the heater 40 (condition 1). Here, the impedance is a quantity representing the difficulty of current flow in an AC circuit, and corresponds to a resistance in a DC circuit. Inductance and capacitance contribute to impedance in addition to resistance. In the present embodiment, the battery 20 is charged by direct current by supplying power from the external power supply device 100, but it is appropriate to use impedance when performing switching control described later. The resistance value R _limit is, for example, 1 kΩ. As a result, even when the internal resistance of the battery 20 is low at a low temperature, a high resistance value can be given to the battery circuit 27, and the battery 20 is supplied to the battery 20 with respect to the current supplied to the heater 40. The ratio of current can be reduced. Further, the resistance value R _limit of the limiting resistance unit 28 has a relationship between the resistance value R _heater of the heater 40, the current value I _heater flowing into the heater 40, and the minimum current value I _{min flowing into the battery 20.}
R _heater × I _heater / I _min <R _limit
It is preferable to have a resistance value that satisfies (Condition 2). In this way, the resistance value R _limit of the limiting resistance unit 28 is set so as to satisfy the above condition 2 in addition to the above condition 1, so that the minimum current value I _min that flows into the battery 20 more reliably is minimized. Can be transformed into. Further, although the limiting resistance portion 28 has been described as being a fixed resistance having a fixed resistance value, it may be configured to include a variable resistance element. Further, it may be composed of a combination of a plurality of impedance elements including a resistance component. Although the limiting resistor portion 28 is incorporated in the positive electrode side main contactor portion 22a in the present embodiment, it may be connected in series with the battery 20 from the branch point X shown in FIG. 2 via the battery 20. It may be placed anywhere up to the branch point Y.

In the third electric circuit 24c, the precharge relay 26 and the second resistor R2 are connected in series. The main relays 23a, 23b, etc. as described above may be welded due to aged deterioration due to long-term use, arcs generated during opening / closing operation, and the like. The precharge relay 26 is a relay used for detecting such welding and suppressing an inrush current. Specifically, the pre-charge relay 26 is used to connect and disconnect each relay at the time of starting the vehicle 10 or starting charging from the external power supply device 100, and to determine whether or not welding is performed. Further, since the resistor R2 is inserted in series with the precharge relay 26, the precharge relay 26 is connected, the current is supplied via the resistor R2, and then the positive electrode side main relay 23a is connected. , The inrush current can be relaxed. The resistor R2 can be of several tens of Ω from the viewpoint of suppressing power consumption, and is, for example, 30 Ω.

The configuration of the positive electrode side main contactor portion 22a described above may be replaced with the configuration of the negative electrode side main contactor portion 22b.

The heater 40 is provided with an electric circuit HLP41a between the branch point X and the heater 40 shown in FIG. 2, and an electric path HLN41b between the branch point Y and the heater 40. That is, the heater 40 and the battery 20 are connected in parallel to the vehicle-mounted charger 17 by the heater circuit 43 and the battery circuit 27. Further, a positive electrode side heater relay 42a is inserted in the electric circuit HLP41a, and a negative electrode side heater relay 42b is inserted in the electric circuit HLN41b in series, and power from the battery 20 or the external power supply device 100 is used by connecting both of these relays. The heater 40 can be energized. The positive electrode side heater relay 42a and the negative electrode side heater relay 42b are controlled by a command from the heater control unit 52.

The positive electrode side main relay 23a, the negative electrode side main relay 23b, the heat mode relay 25, the precharge relay 26, and the heater relay 42 may be, for example, a non-contact type semiconductor relay or the like, or a contact type electromagnetic mechanical relay or the like. Further, each of these relays is normally off, and when the ignition switch of the vehicle 10 is off, the relays are not energized, so that each relay is always turned off.

The ECU 50 is communicably connected to the battery 20, the heater 40, the in-vehicle charger 17, and the like. The ECU 50 can acquire information on the battery state such as SOC (State Of Charge) corresponding to the charge amount of the battery 20 and the battery temperature Tb from the battery 20. In addition, the ECU 50 can also acquire information on whether or not the external power supply device 100 is connected from the in-vehicle charger 17. The ECU 50 is not limited to a configuration in which information is directly acquired from each device or directly controls each device, and for example, information on the battery status may be acquired or controlled via a control unit for battery management (not shown). good.

The switch control unit 51 has a function of controlling switches including the main relay 23 in the junction box 16. In particular, when the external power supply device 100 is connected to the in-vehicle charger 17, it has a function of connecting and disconnecting switches and performing charging control based on the battery state such as the battery temperature Tb and SOC.

The heater control unit 52 has a function of controlling the heater 40 to be energized or shut off in order to raise the temperature of the battery 20 based on the information from the battery temperature sensor 53. The battery temperature sensor 53 is a sensor that is arranged in the vicinity of the battery 20 and detects the battery temperature Tb of the battery 20. The battery temperature Tb is acquired by the ECU 50 at predetermined intervals. Then, the heater control unit 52 determines whether or not the battery temperature Tb is less than a predetermined threshold value Ts at the start of charging the battery 20. As a result of the determination, if it is less than a predetermined threshold value Ts, the heater control unit 52 energizes the heater 40, and as a result, the temperature of the battery 20 is raised. After that, when the battery temperature Tb becomes equal to or higher than the threshold value Ts, the heater control unit 52 shuts off the energization of the heater 40 and ends the temperature rise of the battery 20.

Although the switch control unit 51 and the heater control unit 52 are incorporated in the ECU 50 in this embodiment, they may be individually mounted as modules or programs. Further, the switch control unit 51 and the heater control unit 52 may have a function of performing control by combining information acquired by communicating with the ECU 50 and other devices.

Next, when the battery 20 is charged by receiving electric power from the external power supply device 100, a normal mode in which the heater 40 is not energized and a heat mode in which the heater 40 is energized will be described.

When charging the battery 20 from the external power supply device 100, as described above, the heater control unit 52 determines whether or not to energize the heater 40.

When the heater control unit 52 determines that the heater 40 is not energized, charging is performed in the normal mode. That is, the switch control unit 51 performs a predetermined welding check using the precharge relay 26. If there is no problem in the check, all relays that can connect and disconnect the battery 20 and the heater 40 and the in-vehicle charger 17 are disconnected. After that, first, the negative electrode side main relay 23b is in contact, and then the positive electrode side main relay 23a is in contact, and the battery 20 and the vehicle-mounted charger 17 are made conductive to receive power from the external power supply device 100.

On the other hand, when the heater control unit 52 determines that the heater 40 is energized, the heater 40 is charged in the heat mode. At that time, the switch control unit 51 can connect and disconnect the battery 20 and the heater 40 and the in-vehicle charger 17 if there is no problem in the check after performing a predetermined welding check using the precharge relay 26. Turn off all relays. After that, first the negative electrode side main relay 23b is brought into contact, and then the heat mode relay 25 of the second electric circuit 24b on the battery positive electrode side is brought into contact. As a result, the resistor R1 of the limiting resistor portion 28 is connected to the external power supply device 100 via the vehicle-mounted charger 17 in a configuration in which the resistor R1 is connected in series with the battery 20. Further, the heater control unit 52 connects the negative electrode side heater relay 42b and the positive electrode side heater relay 42a in this order. As a result, the heater 40 conducts with the external power supply device 100 via the vehicle-mounted charger 17. As a result, the inflow of current into the battery 20 is restricted by the resistor R1 having a resistance _{value R limit} larger than the _{resistance value R heater of the heater 40.}

FIG. 3 is a flowchart showing a process when the battery 20 is charged from the external power supply device 100 executed by the battery control device 1 of the present embodiment.

First, the battery control device 1 starts the process when the external power supply device 100 is connected. In step S1, the heater control unit 52 determines whether or not the battery temperature Tb acquired from the battery temperature sensor 53 is smaller than the threshold value Ts. If the determination result is true (YES), the process shifts to the heat mode and proceeds to step S2. On the other hand, if the determination result is false (NO), the process proceeds to step S7.

In step S2, the switch control unit 51 contacts the negative electrode side main relay 23b and the heat mode relay 25. Then, the process proceeds to step S3.

In step S3, the heater control unit 52 contacts the heater relays 42a and 42b. As a result, electric power is applied to the heater 40, and heating of the battery 20 is started. Then, the process proceeds to step S4.

In step S4, the heater control unit 52 compares the battery temperature Tb acquired from the battery temperature sensor 53 with the threshold value Ts in the same manner as in step S1, and determines whether or not it is Ts or more. If the determination result is true (YES), the process proceeds to step S5. On the other hand, if the determination result is false (NO), the process returns to step S4 and the routine of monitoring the battery temperature Tb by the heater control unit 52 is repeated.

In step S5, the heater control unit 52 disconnects the heater relays 42a and 42b, and stops energizing the heater 40. Then, the process proceeds to step S6.

In step S6, the switch control unit 51 disconnects the heat mode relay 25, and the current limitation by the limiting resistor unit 28 is released. Then, the process proceeds to step S7.

In step S7, the switch control unit 51 contacts the positive electrode side main relay 23a, the external power supply device 100 normally charges the battery 20, and the routine ends.

According to the battery control device 1 of the vehicle 10 according to the above embodiment, the battery 20 for supplying electric power to the motor 11 for driving the vehicle 10 and the vehicle-mounted battery 20 for supplying electric power supplied from the external power supply device 100 to the battery 20. The charger 17, the positive side main contactor unit 22a (switch unit) for connecting and disconnecting the battery 20 and the vehicle-mounted charger 17, and the switch control unit 51 for controlling the connection and disconnection of the positive side main contactor unit 22a. A heater 40 connected to the vehicle-mounted charger 17 to raise the temperature of the battery 20, a heater control unit 52 for controlling energization of the heater 40, and a limiting resistance unit 28 having an impedance higher than that of the heater 40. When the heater control unit 52 determines that the heater 40 is energized when charging the battery 20 from the external power supply device 100, the switch control unit 51 has a limiting resistance unit 28 in series with the battery 20. Control is performed so that the positive side heat mode relay 25 is in contact with the positive side heat mode relay 25 so as to be connected. As a result, when charging the battery 20 from the external power supply device 100, when the electric power of the external power supply device 100 is applied to the heater 40 to raise the temperature of the battery, the battery 20 and the external power supply device 100 are connected according to the request of fail-safe. If the positive electrode side heat mode relay 25 is conducted in the positive electrode side main contactor portion 22a (switch portion), a resistor R1 having a resistance value R _{limit larger than the resistance value R heater of the heater 40 is provided in series with the battery 20.} As a result, while satisfying the requirements of the fail-safe design, the current from the external power supply device 100 is restricted from flowing into the battery 20, the risk of short circuit of the battery 20 can be prevented from increasing or deterioration, and more can be applied to the heater 40. The temperature of the battery 20 can be quickly raised by the flow of the current.

Further, the impedance value Z _limit of the limiting resistor portion 28 has a relationship between the impedance value Zheater of the heater 40, the current value I _heater flowing into the heater 40, and the minimum current value I _min flowing into the battery 20.
Z _heater x I _heater / I _min <Z _limitsy
It can be a value that satisfies. As a result, in the system design, by setting the minimum current value I _min flowing into the battery 20 to a value capable of suppressing battery deterioration, the current value I _heater flowing into the heater 40 and the impedance value Z _{heater of the heater 40} Therefore, the minimum value of the _{impedance value Z limit} of the limiting resistance unit 28 can be determined.

Further, the positive electrode side main contactor portion 22a (switch portion) is configured in parallel with the first electric circuit 24a having the positive electrode side main relay 23a and the first electric circuit 24a, and is connected in series with the resistor R1. When the heater control unit 52 determines that the heater 40 is energized when charging the battery 20 from the external power supply device 100, the switch control unit 51 sets the positive electrode side main relay 23a. By performing control with the heat mode relay 25 as a contact, it can be added only when it is necessary to add a limiting resistor.

Further, a battery temperature sensor 53 that detects the battery temperature Tb of the battery 20 is provided, and the heater control unit 52 energizes the heater 40 based on the battery temperature Tb, so that the battery 20 is likely to deteriorate in an extremely low temperature environment. In the battery charging of the above, the inflow of current from the external power supply device 100 to the battery 20 can be restricted, and as a result, the risk of short circuit and deterioration of the battery 20 can be suppressed.

Further, the switch control unit 51 controls to change the impedance of the limiting resistor unit 28 based on the battery temperature Tb acquired from the battery temperature sensor 53, thereby increasing or decreasing the impedance according to the rise or fall of the battery temperature Tb. The inflow current from the external power supply device 100 to the battery 20 can be increased or decreased. As a result, while preventing deterioration of the battery 20 (battery protection), charging can be performed while the temperature of the battery 20 is raised by the heater 40, and the time from the start of the temperature rise to the end of charging can be shortened (time reduction). As a result, the energy supplied from the external charging device 100 can be efficiently used (energy efficiency utilization).

Further, by configuring the limiting resistance unit 28 to include the variable resistor, the switch control unit 51 controls to reduce the resistance value of the variable resistor of the limiting resistance unit 28 as the battery temperature Tb rises, and externally. Since the amount of current inflow (charging current) from the power supply device 100 to the battery 20 can be increased, the above-mentioned effects of battery protection, time reduction, and energy efficiency utilization can be obtained.

Further, by inserting the limiting resistor portion 28 into the positive electrode side electric circuit BNP 21a of the battery 20, the inrush current to the battery 20 can be relaxed.

Although the description of the embodiment of the present invention is completed above, the aspect of the present invention is not limited to this embodiment.

For example, as shown in FIG. 4, the limiting resistor section 28 includes a resistor R1', a heat mode relay 25 connected in series with the resistor R1', and a limiting resistor relay 29a connected in parallel with the resistor R1'. It may be configured as follows. Specifically, while the switch control unit 51 is in contact with the heat mode relay 25, the switch control unit 51 PWMs the opening / closing speed of the limiting resistor relay 29a connected to the bypass path connected in parallel to the resistor R1'. Control (switching control) that changes by control may be performed. As a result, the time during which the resistor R1'is added to the battery circuit according to the change in the battery temperature Tb and the state in which the resistor R1'is substantially not added to the battery circuit via the bypass path. The allocation with time can be changed. That is, according to this configuration, the time average impedance of the limiting resistor portion 28 can be changed by the opening / closing time of the limiting resistor relay 29a. Therefore, since the current limit amount can be changed, for example, when the battery temperature Tb rises, the current limit amount can be reduced. As a result, the above-mentioned effects of battery protection, time saving and energy efficiency utilization can be obtained.

Further, for example, as shown in FIG. 5, the limiting resistor portion 28 includes a resistor R1 ", a heat mode relay 25 connected in series with the resistor R1", and an inductor 29b connected in series with the resistor R1 ". And the limiting resistor relay 29 (third switch) connected in parallel to the resistor R1 ”may be included. Specifically, while the switch control unit 51 is in contact with the heat mode relay 25, the switch control unit 51 further changes the opening / closing speed of the limiting resistor relay 29a connected in parallel to the resistor R1 ”by PWM control or the like. Control may be performed. As a result, the time during which the resistor R1 ”and the relay 29b are added to the battery circuit and the time during which only the relay 29b is added according to the change in the battery temperature Tb. Distribution can be changed. Further, since the impedance of the inductor 29b increases as the switching cycle becomes higher, an impedance larger than that of the resistor R1 "can be added to the limiting resistor section 28. On the other hand, the inductor is connected in parallel to the resistor R1". When the limiting resistor relay 29a is maintained in contact (when switching is not performed), the impedance of the inductor 29b becomes substantially 0, and the current can be limited only by the resistor R1 ”. As a result, the above battery protection and time reduction can be performed. And the effect of energy efficiency utilization can be obtained.

Further, in the above embodiment, the determination to operate the heater 40 is made based on the battery temperature Tb. For example, the SOC (State Of Charge) corresponding to the charge amount of the battery 20, the internal resistance of the battery 20, and the outside Information such as temperature may be combined as appropriate, and a judgment may be made based on such information.

1 Battery control device 10 Vehicle 11 Motor 12 Power transmission unit 13 Drive shaft 14 Drive wheel 15 Inverter 16 Junction box 17 In-vehicle charger 20 Drive battery 21a Positive electrode side electric circuit BLP
21b Negative electrode side electric circuit BLN
22a Positive electrode side main contactor part 22b Negative electrode side main contactor part 23a Positive electrode side main relay 23b Negative electrode side main relay 24a First electric circuit (L1)
24b 2nd electric line (L2)
24c 3rd electric line (L3)
25 Heat mode relay 26 Precharge relay 27 Battery circuit 28 Limiting resistance part 29a Limiting resistance relay 29b Inductor 30 Power receiving terminal 40 Heater (PTC heater)
41a Electric circuit HLP
41b Electric circuit HLN
42a Positive electrode side heater relay 42b Negative electrode side heater relay 43 Heater circuit 50 Vehicle control unit (ECU)
51 Switch control unit 52 Heater control unit 53 Battery temperature sensor 60 CAN
100 External power supply 101 Power supply terminal (connector)
R1 1st resistor (resistance value R _limit )
R2 2nd resistor

Claims (8)

A battery to power the motor that drives the vehicle,
A charge control unit for supplying the electric power supplied from the external power supply device to the battery, and
A switch unit for connecting and disconnecting the battery and the charge control unit,
A switch control unit for controlling the disconnection and connection of the switch unit,
A heater connected to the charge control unit to raise the temperature of the battery,
A heater control unit for controlling the energization of the heater and
A limiting resistor having an impedance higher than the impedance of the heater,
Including
When the heater control unit determines that the heater is energized when charging the battery from the external power supply device, the switch control unit is such that the limiting resistance unit is connected in series with the battery. A vehicle battery control device that controls the switch unit in contact with the switch. The impedance value Z _limit of the limiting resistor is
The impedance value Z _heater of the heater and
The current value I _heater flowing into the heater and
The minimum current value I _min flowing into the battery and
Relationship,
Z _heater × I _heater / I _min <Z _limit
The vehicle battery control device according to claim 1, which has a value of. The switch unit
The first path with the first switch and
A second path including a second switch configured in parallel with the first path and connected in series with the limiting resistor.
Including
When the heater control unit determines that the heater is energized when charging the battery from the external power supply device, the switch control unit disconnects the first switch and contacts the second switch. The vehicle battery control device according to claim 1 or 2. Further equipped with a temperature sensor for detecting the temperature of the battery,
The vehicle battery control device according to any one of claims 1 to 3, wherein the heater control unit determines whether or not to energize the heater based on information from the temperature sensor. The vehicle battery control device according to claim 4, wherein the switch control unit controls to change the impedance of the limiting resistor unit based on the information of the temperature sensor. The vehicle battery control device according to any one of claims 1 to 5, wherein the limiting resistance unit includes a variable resistor. The limiting resistor includes a resistor and a third switch connected in parallel to the resistor.
The switch control unit controls to change the opening / closing speed of the third switch while the switch control unit is in contact with the second switch. The vehicle battery control device according to claim 1. The vehicle battery control device according to any one of claims 1 to 7, wherein the limiting resistor portion is provided on the positive electrode side of the battery.

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