JP2020059375A - Temperature control system of battery for vehicle driving - Google Patents

Abstract

To provide a temperature control system which can reduce the size of a battery for vehicle driving.SOLUTION: A temperature control system 100 of a battery for vehicle driving includes a battery 10 for vehicle driving, a motor 40 for vehicle driving, a first radiator circuit 50, a power control unit (PCU) 30 having a driving circuit 32 driving the motor 40 for vehicle driving, a second radiator circuit 60, and a circulation circuit 70. When the battery 10 for vehicle driving is equal to or lower than a predetermined temperature, circulation of a medium in the first radiator circuit in the first radiation 58 is blocked with a first valve 51, circulation of a medium in the second radiator circuit in a second radiator 68 is blocked with a second valve 62, circulation of the media in the first radiator circuit and the second radiator circuit in the circulation circuit are permitted with third and fourth valves 73 and 74 and the driving circuit 32 is operated in a state in which power conversion efficiency of the driving circuit 32 is lowered.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a system for controlling the temperature (battery temperature) of a drive battery mounted on a vehicle such as an electric vehicle (EV), and particularly when the battery temperature before starting is low because the outside air temperature is low. , Its battery temperature can be raised.

  For example, according to the vehicle warm-up control device disclosed in Patent Document 1, the warm-up heater is mounted on the vehicle, and the warm-up heater controls the current supplied from the battery and the current supplied from the external power source. It can be used to generate heat for warming up the vehicle (paragraph [0020] of Patent Document 1). The heat for warming up here means all the heat for warming the power plant (power unit) at the time of cold start of the vehicle, and is used, for example, to raise the temperature of the battery and the motor for traveling. Further, in the case of a hybrid vehicle equipped with an engine in addition to the electric motor, the heat is used to warm the engine body, engine oil, engine cooling water, and other in-vehicle devices. In the vehicle warm-up control device disclosed in Patent Document 1, a heater is mainly used to raise the temperature of the battery after charging the battery with an external power source. The warm-up control for raising the temperature of the battery may be performed not only after charging the battery but also before or during charging (paragraph [0020] of Patent Document 1).

JP, 2005-027220, A

  However, the warm-up heater has a drawback that the power consumption is relatively large. In addition, in order to warm the drive battery with the warm-up heater, it is necessary to dispose the warm-up heater around the drive battery, and the disposition space is required only for the drive battery.

  An object of the present invention is to provide a temperature control system capable of miniaturizing a vehicle drive battery. Other objects of the present invention will become apparent to those skilled in the art by referring to the aspects and best modes illustrated below, and the attached drawings.

  Hereinafter, for easy understanding of the outline of the present invention, embodiments according to the present invention will be exemplified.

In the present aspect, the temperature control system for the vehicle drive battery is a first radiator circuit capable of cooling the vehicle drive battery, the vehicle drive motor by the electric power from the vehicle drive battery, and the vehicle drive battery. A power control unit (PCU) having a drive circuit for driving the vehicle drive motor; a second radiator circuit capable of cooling the vehicle drive motor and the drive circuit; and a first radiator circuit in the first radiator circuit. And a circulation circuit capable of circulating the medium and the medium in the second radiator circuit,
Equipped with
When the vehicle driving battery has a temperature equal to or lower than a predetermined temperature, the first valve prevents the medium in the first radiator circuit from circulating in the first radiator circuit, and the medium in the second radiator circuit is blocked. A second valve prevents the medium from circulating in the second radiator, and a third valve allows the medium in the first radiator circuit to circulate in the circulation circuit; A fourth valve permits the medium in the second radiator circuit to circulate in the circulation circuit, and the drive circuit is operated in a state in which the power conversion efficiency of the drive circuit is reduced.

  According to this aspect, since the power conversion efficiency is lowered, the heat in the drive circuit is intentionally increased as compared with the normal time. The heat can be transferred from the second radiator circuit to the first radiator circuit through the circulation circuit, and as a result, the vehicle drive battery can be warmed. Since the first radiator circuit capable of adjusting the temperature of the vehicle driving battery is an existing circuit, the arrangement space of the circulation circuit is small compared to the case where the warming-up heater is arranged around the driving battery. Can be converted.

  Those skilled in the art will readily appreciate that the illustrated embodiments according to the invention may be further modified without departing from the spirit of the invention.

1A and 1B are schematic block diagrams for explaining a configuration example of a temperature control system for a vehicle drive battery, and FIG. 1A shows a low temperature drive vehicle battery. FIG. 1B shows the flow of the medium (cooling water) during the normal operation (normal running) when the temperature is low, and FIG. 1B shows the flow of the medium during the heat operation when the temperature of the vehicle driving battery is low.

  The best mode described below is used for easy understanding of the present invention. Therefore, those skilled in the art should note that the present invention is not unduly limited by the embodiments described below.

  Reference is made to FIG. FIG. 1A shows the flow of the medium (cooling water) during normal operation (normal running) when the temperature of the vehicle drive battery 10 is not low. In other words, when a vehicle such as an electric vehicle (EV) is traveling, the electric power of the vehicle drive battery 10 is consumed or charged to suppress the heat generation of the vehicle drive battery 10. A first radiator circuit 50 capable of cooling the drive battery 10 is provided. That is, when the vehicle is traveling, the heat of the medium that circulates in the first radiator circuit 50 is released to the outside of the vehicle through the first radiator 58, becomes cooling water, and becomes the surroundings of the vehicle drive battery 10. It can circulate or flow.

  In the example shown in FIG. 1A, the first radiator circuit 50 is provided with a first circulation pump 59 (water pump) and a first valve 51, and the first circulation circuit 59 and the first valve 51 are provided according to the temperature of the vehicle drive battery 10. The first circulation pump 59 operates, and if necessary, the opening degree of the first valve 51 (medium flow rate) is adjusted. In the example of FIG. 1A, the first valve 51 is fully opened, and the cooling water flows from the first radiator 58 into the vehicle drive battery 10 by the first circulation pump 59, which is preferably an electric pump. .

  In general, the rated temperature of the vehicle driving battery 10 and the rated temperatures of the power control unit (PCU) 30 and the vehicle driving motor 40 are different, so that the medium in the first radiator circuit 50 is the second radiator circuit 60. A second radiator circuit 60 capable of cooling the power control unit 30 and the vehicle driving motor 40, whose cooling water passages are separated, is provided so as not to mix inside. The power control unit 30 mainly includes a drive circuit 32 that generates heat, and when the vehicle travels, the heat of the medium circulating in the second radiator circuit 60 is released to the outside of the vehicle via the second radiator 68. As cooling water, it can circulate or flow around the power control unit 30 (particularly the drive circuit 32) and the vehicle drive motor 40.

  In the example of FIG. 1 (A), the second radiator circuit 60 is provided with a second circulation pump 69 (water pump) and a second valve 62, and the temperature of the power control unit 30 and the vehicle drive motor 40 is reduced. The second circulation pump 69 operates according to the above, and the opening degree of the second valve 62 (medium flow rate) is adjusted as necessary. In the example of FIG. 1 (A), the second valve 62 is fully opened, and cooling water is supplied from the second radiator 68 to the power control unit 30 and the vehicle by the second circulation pump 69, which is preferably an electric pump. It flows into the motor 40.

  In the example of FIG. 1A, the vehicle drive battery 10 is, for example, a high-voltage battery of several hundred [V] or higher, and the power control unit 30 rotates wheels of a vehicle such as an electric vehicle or a hybrid vehicle. It has the drive circuit 32 (for example, DC-AC inverter circuit) for driving the vehicle drive motor 40 (for example, three-phase motor). The configuration of the drive circuit 32 that drives the vehicle drive motor 40 is known, and therefore description thereof will be omitted. It is disclosed in Japanese Patent No. 107893 (motor drive inverter Im) and the like.

  A J / B (junction box) 20 in FIG. 1A can include a relay circuit or the like that can supply / interrupt the electric power of the vehicle driving battery 10, and protects the electrodes or terminals of the vehicle driving battery 10. be able to.

  Reference is made to FIG. FIG. 1B shows the flow of the medium during the heating operation when the temperature of the vehicle driving battery 10 is low. The vehicle drive battery 10 has a rated temperature in order to ensure its performance. In other words, at the time of starting the vehicle such as in the morning of midwinter, the temperature of the battery 10 for driving the vehicle is low, so that the performance thereof is degraded. Therefore, in Patent Document 1, a dedicated heater is provided in order to improve or ensure its performance.

  In the embodiment according to the present invention, as shown in FIG. 1B, the temperature control system 100 for the vehicle or the vehicle driving battery 10 does not have such a heater. In other words, since the performance deterioration of the vehicle drive battery 10 is known, the temperature control system 100 can set the threshold value or the low temperature appropriately according to the specific specifications of the vehicle drive battery 10. However, the temperature control system 100 of FIG. 1B includes a circulation circuit 70 instead of the conventional heater. Further, as will be described later, the temperature control system 100 is characterized by operating the drive circuit 32 in a state where the power conversion efficiency of the drive circuit 32 is reduced when the vehicle drive battery 10 is at a low temperature.

  Note that whether or not the temperature of the vehicle driving battery 10 is equal to or lower than a threshold value (low temperature) may be performed by a calculation unit (CPU) of the power control unit 30 or by a battery control control unit (not shown). Alternatively, it may be implemented by a vehicle power control unit (VCU) that integrates them. Similarly, the other determination and the other control may be actually performed by any arithmetic unit.

  When the temperature of the vehicle driving battery 10 is below a threshold value (predetermined temperature), the medium (preferably antifreeze liquid / cooling water) in the first radiator circuit 50 circulates in the first radiator 58. Valve 51 to prevent the medium in the second radiator circuit 60 from circulating in the second radiator 68 by the second valve 62, and the medium in the first radiator circuit 50 to the circulating circuit 70. A third valve 73 permits circulation therein, and a fourth valve 74 permits the medium in the second radiator circuit 60 to circulate in the circulation circuit 70. In the example of FIG. 1 (B), the first valve 51 and the second valve 62 are fully closed, the third valve 73 and the fourth valve 74 are fully opened, and the first circulation pump 59 and the By the second circulation pump 69, the medium does not flow into the first radiator 58 and the second radiator 68, and the circulation circuit 70 causes the medium in the first radiator circuit 50 and the medium in the second radiator circuit 60. And circulate.

  In the example of FIG. 1B, since the power conversion efficiency of the drive circuit 32 is reduced, the heat in the drive circuit 32 is intentionally increased as compared with the normal time. The heat can be transferred from the second radiator circuit 60 to the first radiator circuit 50 via the circulation circuit 70, and as a result, the vehicle drive battery 10 can be warmed.

  As an example, a vehicle power control unit (VCU) (not shown) determines whether or not the temperature of the vehicle drive battery 10 is equal to or lower than a predetermined temperature, and preferably the VCU determines that the temperature of the vehicle drive battery 10 is equal to or lower than the predetermined temperature. The radiator circuit of FIG. 1B is adopted or implemented when the start switch (for example, a start button) (not shown) of the vehicle drive motor 40 is turned on. After that, when the temperature of the vehicle drive battery 10 exceeds a predetermined temperature, for example, the VCU normally adopts or implements the radiator circuit of FIG. 1A, and normally reduces the power conversion efficiency of the drive circuit 32. Return to the state. Note that, for example, the VCU determines whether or not the start timer of the vehicle drive motor 40 is turned on, instead of determining whether or not the start switch of the vehicle drive motor 40 is turned on. A radiator circuit may be adopted or implemented.

  In the example of FIG. 1B, the state in which the power conversion efficiency of the drive circuit 32 is reduced means, for example, that the drive circuit 32 or each switching element that constitutes the DC-AC inverter circuit is driven from the upper and lower arm switching elements. Changing to one-arm switching, increasing the frequency (carrier frequency) that determines the pulse width modulation period when PWM controlling each switching element, gate resistance of each switching element (rise time Tr and fall time Tf) Is increased, and the gate voltage of each switching element is decreased (the collector-emitter saturation voltage VCE (sat) is increased).

  In addition, the state in which the power conversion efficiency of the drive circuit 32 is reduced means that the drive circuit 32 generates a current (predetermined current) that does not rotate the vehicle drive motor 40 even when the vehicle is stopped. Yes, preferably, the drive circuit 32 can generate a maximum current at which the vehicle drive motor 40 does not rotate when the vehicle is stopped, and can supply the maximum current to the vehicle drive motor 40.

  Note that the power control unit (PCU) 30 further includes a power circuit such as another inverter (power generation inverter Ig) as well as the motor driving inverter Im, as disclosed in JP-A-2018-107893. At times, the power control unit 30 of FIG. 1 (B) may reduce conversion efficiency as a whole and generate more heat.

  Further, when the second radiator circuit 60 can also cool the vehicle power control unit (VCU), for example, the voltage supplied to the VCU is changed from a high voltage to a low voltage to increase energy loss due to a transient response. The heat can also warm the vehicle drive battery 10.

  The present invention is not limited to the above-described exemplary embodiments, and those skilled in the art can easily change the above-described exemplary embodiments to the scope included in the claims. .

  10 ... Vehicle drive battery, 20 ... Junction box, 30 ... Power control unit, 32 ... Drive circuit, 40 ... Vehicle drive motor, 50, 60 ... Radiator circuit, 51 , 62 ... Valve, 58, 68 ... Radiator, 59, 69 ... Circulation pump, 70 ... Circulation circuit, 73, 74 ... Valve, 100 ... Temperature control system.

Claims (1)

A vehicle drive battery,
A vehicle drive motor by electric power from the vehicle drive battery,
A first radiator circuit capable of cooling the vehicle drive battery;
A power control unit (PCU) having a drive circuit for driving the vehicle drive motor;
A second radiator circuit capable of cooling the vehicle drive motor and the drive circuit;
A circulation circuit capable of circulating the medium in the first radiator circuit and the medium in the second radiator circuit;
Equipped with
When the vehicle driving battery has a temperature equal to or lower than a predetermined temperature, the first valve prevents the medium in the first radiator circuit from circulating in the first radiator circuit, and the medium in the second radiator circuit is blocked. A second valve prevents the medium from circulating in the second radiator, and a third valve allows the medium in the first radiator circuit to circulate in the circulation circuit; A fourth valve allows the medium in the second radiator circuit to circulate in the circulation circuit, and the drive circuit is operated in a state where the power conversion efficiency of the drive circuit is reduced. A characteristic temperature control system for a vehicle drive battery.

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