Electric motor car

Abstract

To provide a technique which enables improvement of energy efficiency with respect to heating inside a cabin of an electric motor car.SOLUTION: An electric motor car comprises a battery, a cooling system for cooling the battery, and an air conditioning system for heating inside a cabin by using heat generated by power supplied from the battery and waste-heat from the cooling system. When a heating request is predicted to be issued to the air conditioning system, the cooling system sets a cooling target temperature of the battery to a higher temperature than a prescribed standard value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This specification relates to an electric vehicle, and in particular to heating of the vehicle interior. The electric vehicle referred to here includes a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a fuel cell electric vehicle (FCEV), and the like. [Background technology]

[0002] Patent Document 1 describes an electric vehicle. This electric vehicle is equipped with a cooling system that cools a high-voltage battery (hereinafter simply referred to as the battery) for driving, and an air conditioning system that heats the interior of the vehicle. The air conditioning system is configured to heat the interior of the vehicle using heat generated by a heater supplied with power from the battery and exhaust heat from the cooling system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-192884 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described conventional configuration, when the heating of the vehicle interior is not performed, the heat exhausted by the cooling system is released to the outside. When the heating of the vehicle interior is started thereafter, the heat exhausted from the cooling system alone is usually insufficient, so heat generated by the heating element by the power supply from the battery is also used. When the power of the battery is consumed for heating the vehicle interior, the energy efficiency (also referred to as fuel efficiency or electricity cost) of the electric vehicle decreases. This specification provides a technology that can improve the energy efficiency regarding the heating of the vehicle interior in an electric vehicle. [Means for solving the problem]

[0005] The electric vehicle disclosed in this specification includes a battery, a cooling system that cools the battery, and an air conditioning system that heats the vehicle interior using heat generated by the power supplied to the battery and exhaust heat from the cooling system, and the cooling system sets a cooling target temperature of the battery to a temperature higher than a predetermined standard value when a heating request is predicted for the air conditioning system.

[0006] In the configuration according to the present technology, even if the vehicle interior is not heated, when the vehicle interior is predicted to be heated in the future, the exhaust heat discharged from the cooling system to the outside can be suppressed and the heat can be stored in the battery. As a result, when the vehicle interior is subsequently heated, the amount of heat required for the heater is reduced and the power consumption from the battery is suppressed. This improves the energy efficiency of the electric vehicle.

[0007] In the above-mentioned configuration, the cooling system may set the cooling target temperature of the battery to a temperature higher than a predetermined standard value when a heating request is predicted for the air conditioning system and parking is predicted before the heating prediction. The battery does not substantially generate heat while the electric vehicle is parked. Therefore, when parking of the electric vehicle is predicted, it is preferable to further suppress the exhaust heat released to the outside from the cooling system and store a large amount of heat in the battery. [Brief description of the drawings]

[0008] [Figure 1] 4 is a flowchart of a process executed by an electric vehicle. [Diagram 2] FIG. 2(a) is a time chart when the electric vehicle is stopped, and FIG. 2(b) is a time chart when the electric vehicle is running. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] This specification discloses technology related to an electric vehicle equipped with a battery and a motor for driving. In this specification, "electric vehicle" includes battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell electric vehicles (FCEVs), etc.

[0010] The electric power output by the battery is converted by a power conversion device. The electric vehicle can run by supplying the electric power converted by the power conversion device to a motor for running. The battery is, for example, a secondary battery such as a lithium ion battery.

[0011] When a current flows through a battery during battery operation or charging, the battery generates heat. For this reason, electric vehicles are equipped with a cooling system to cool the battery. The cooling system uses, for example, a liquid refrigerant (such as water or LLC (short for Long Life Coolant)) to cool the battery.

[0012] The electric vehicle also includes an air conditioning system that heats the vehicle cabin. The air conditioning system of this embodiment heats the vehicle cabin using heat generated by power supplied from the battery and exhaust heat from the cooling system. That is, the electric vehicle includes a heater that generates heat using power supplied from the battery, and can heat the vehicle cabin using the heat generated by the heater. The electric vehicle also generates hot air using a refrigerant whose temperature has increased by cooling the battery, and supplies the hot air to the vehicle cabin, thereby heating the vehicle cabin.

[0013] In heating using heat generated by the battery's power supply, the battery consumes a lot of power to generate heat. This may result in a decrease in the energy efficiency of the electric vehicle. To avoid this, it is effective to use more of the exhaust heat from the battery's cooling system (i.e., the battery's Joule heat) for heating. Therefore, the control device for an electric vehicle in this embodiment improves the energy efficiency of the electric vehicle by executing the process shown in FIG. 1, which will be described below.

[0014] The process executed by the control device mounted on the electric vehicle of this embodiment will be described with reference to Fig. 1. In the following, for ease of understanding, the electric vehicle will be described as the subject of the process instead of the control device. In S10, the electric vehicle determines whether or not the electric vehicle is being charged. If the electric vehicle determines that it is being charged (YES in S10), it proceeds to S12, and if it determines that it is not being charged (NO in S10), it proceeds to S20.

[0015] In S12, the electric vehicle determines whether or not the situation is such that use of the heater is predicted (i.e., a heating request is predicted for the air conditioning system). The electric vehicle determines whether or not the situation is such that use of the heater is predicted by using at least one of the following information: outside air temperature, time, temperature inside the vehicle cabin, solar radiation information, user information, wiper operation information, headlight illumination information, and position information. For example, the electric vehicle may determine that the situation is such that use of the heater is predicted when the outside air temperature is equal to or lower than a predetermined temperature, and may determine that the situation is such that use of the heater is predicted when the outside air temperature is higher than the predetermined temperature. If the electric vehicle determines that the situation is such that use of the heater is predicted (NO in S12), it proceeds to S14, and if the electric vehicle determines that the situation is such that use of the heater is predicted (YES in S12), it proceeds to S16.

[0016] In S14, the electric vehicle sets the cooling target temperature of the battery to X [° C.], where X [° C.] is a predetermined standard value of the cooling target temperature when the battery is being charged.

[0017] In S16, the electric vehicle sets the battery cooling target temperature to X+A [°C]. That is, when the electric vehicle determines that the situation predicts the use of heating (YES in S12), it sets the battery cooling target temperature to a temperature higher than a predetermined standard value (i.e., X [°C]) of the cooling target temperature during battery charging.

[0018] Furthermore, if the electric vehicle determines NO in S10, it executes the process of S20. The process of S20 is the same as the process of S12. If the electric vehicle determines YES in S20, it proceeds to S22, and if the electric vehicle determines NO in S20, it proceeds to S24.

[0019] In S22, the electric vehicle determines whether the current battery temperature is within the battery cooling required range. Specifically, the electric vehicle determines whether the current battery temperature is higher than a predetermined temperature. If the current battery temperature is within the battery cooling required range (YES in S22), the electric vehicle proceeds to S26. On the other hand, if the current battery temperature is not within the battery cooling required range (NO in S22), the electric vehicle proceeds to S24.

[0020] In S24, the electric vehicle sets the cooling target temperature of the battery to Y [°C]. Here, temperature Y [°C] is a predetermined standard value of the cooling target temperature when the battery is not being charged. Temperature Y [°C] is a temperature higher than temperature X [°C], which is a predetermined standard value of the cooling target temperature when the battery is being charged.

[0021] In S26, the electric vehicle determines whether or not parking is predicted. The electric vehicle determines whether or not parking is predicted by using, for example, information from a car navigation system. For example, the electric vehicle may determine that parking is predicted when the distance between the current position of the electric vehicle and the home of the user of the electric vehicle is equal to or less than a predetermined distance, and may determine that parking is not predicted when the distance between the current position of the electric vehicle and the home of the user of the electric vehicle is greater than the predetermined distance. If the electric vehicle determines that parking is predicted (YES in S26), it proceeds to S28, and if the electric vehicle determines that parking is not predicted (NO in S26), it proceeds to S30.

[0022] In S28, the electric vehicle sets the battery cooling target temperature to Y+B [°C]. That is, when the electric vehicle determines that the situation is one in which use of heating is predicted, the battery temperature is in a range requiring cooling, and parking is predicted (YES in S20, YES in S22, YES in S26), it sets the battery cooling target temperature to a temperature higher than a predetermined standard value (i.e., Y [°C]) of the cooling target temperature when the battery is not being charged.

[0023] In S30, the electric vehicle sets the battery cooling target temperature to Y+C [°C]. That is, when the electric vehicle determines that the situation is predicted to be one in which heating will be used, that the battery temperature is in a range requiring cooling, and that parking is not predicted (YES in S20, YES in S22, NO in S26), it sets the battery cooling target temperature to a temperature higher than a predetermined standard value (i.e., Y [°C]) of the cooling target temperature when the battery is not being charged. Here, the temperature Y+C [°C] set in S30 is a temperature lower than the temperature Y+B [°C] set in S28.

[0024] Next, specific cases will be described with reference to FIG. 2. First, a case in which an electric vehicle is stopped will be described with reference to FIG. 2(a). The item "Plug-in" in FIG. 2(a) indicates either "OFF" indicating that the electric vehicle is not charging, or "ON" indicating that the electric vehicle is charging. The item "Heating Use Prediction" indicates either "OFF" indicating that the situation is one in which it is predicted that the heating will not be used, or "ON" indicating that the heating will be used. The item "Cooling target temperature" indicates the cooling target temperature of the battery. Also, the curve in FIG. 2(a) indicates the progress of the actual temperature of the battery.

[0025] 2(a), from time t0 to time t1, the electric vehicle is not charging (plugged in = OFF) and is predicted not to use the heater (heating use prediction = OFF). Therefore, from time t0 to time t1, the electric vehicle sets the battery cooling target temperature to Y [°C] (NO in S10, NO in S20, S24 in FIG. 1).

[0026] After that, at time t1, charging of the electric vehicle begins (plug-in = ON). It is predicted that heating will not be used between time t1 and time t2 (heating use prediction = OFF). Therefore, the electric vehicle sets the battery cooling target temperature to X [°C] between time t1 and time t2 (YES in S10, NO in S12, S14 in FIG. 1). As described above, temperature X [°C] is a lower value than temperature Y [°C].

[0027] After that, at time t2, the situation changes to one in which it is predicted that heating will be used (heating use prediction = ON). Therefore, after time t2, the electric vehicle sets the cooling target temperature to X+A [°C] (YES in S10, YES in S12, S16 in FIG. 1).

[0028] Next, a case where the electric vehicle is running will be described with reference to Fig. 2(b). The item "Parking prediction" in Fig. 2(b) indicates either "OFF" indicating that parking is not predicted, or "ON" indicating that parking is predicted. As shown in Fig. 2(b), the battery cooling required range is set to Y [°C] or higher.

[0029] 2(b), from time t10 to time t11, it is predicted that the heating will not be used (heating use prediction = OFF), and parking is not predicted (parking prediction = OFF). Therefore, the electric vehicle sets the battery cooling target temperature to Y [°C] from time t10 to time t11 (NO in S10, NO in S20, S24 in FIG. 1).

[0030] After that, at time t11, the situation changes to one in which it is predicted that heating will be used (heating use prediction = ON). In addition, between time t11 and time t12, the battery temperature is below Y [°C], and therefore the battery temperature is not within the range in which the battery needs to be cooled. Therefore, the electric vehicle maintains the battery cooling target temperature at Y [°C] between time t11 and time t12 (NO in S10, YES in S20, NO in S22, S24 in FIG. 1).

[0031] After that, at time t12, the battery temperature rises to Y [°C]. That is, the battery temperature after time t12 is equal to or higher than Y [°C]. Furthermore, parking is not predicted between time t12 and time t13 (parking prediction = OFF). Therefore, the electric vehicle sets the battery cooling target temperature to Y+C [°C] between time t12 and time t13 (NO in S10, YES in S20, YES in S22, NO in S26, S30 in FIG. 1).

[0032] After that, at time t13, the situation changes to one in which parking is predicted (parking prediction = ON). Therefore, the electric vehicle sets the cooling target temperature to Y+B [°C] after time t13 (NO in S10, YES in S20, YES in S22, YES in S26, S28 in FIG. 1).

[0033] According to the above configuration, even if the heating of the vehicle interior is not being performed, when the heating of the vehicle interior is predicted thereafter, the electric vehicle of this embodiment sets the cooling target temperature of the battery to a temperature higher than a predetermined standard value (see S16, S28, and S30 in FIG. 1). That is, the exhaust heat discharged from the cooling system to the outside can be suppressed, and the amount of heat can be stored in the battery. As a result, when the heating is started thereafter, the amount of heat required for the heater is reduced, and the power consumption from the battery is suppressed. In addition, since the cooling target temperature of the battery is set to a temperature higher than the predetermined standard value, the energy required to cool the battery can be reduced (for example, the power required to drive a pump that supplies refrigerant can be reduced) compared to when the cooling target temperature is the predetermined standard value. This improves the energy efficiency of the electric vehicle.

[0034] Furthermore, with the above configuration, in a situation where the use of the heater is predicted, the electric vehicle sets the target cooling temperature of the battery when parking is predicted to be higher than the target cooling temperature of the battery when parking is not predicted (see S28 and S30 in FIG. 1). While the electric vehicle is parked, the battery does not substantially generate heat. Therefore, when parking of the electric vehicle is predicted, the exhaust heat released to the outside from the cooling system can be further suppressed, and a larger amount of heat can be stored in the battery. That is, the energy efficiency of the electric vehicle is improved.

Claims

[Claim 1] There is an electric car, A battery; a cooling system for cooling the battery; an air conditioning system that heats a vehicle interior using heat generated by the power supplied from the battery and exhaust heat from the cooling system; Equipped with the cooling system sets a cooling target temperature of the battery to a temperature higher than a predetermined standard value when a heating request is predicted for the air conditioning system. Electric car.

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