Electric vehicle

Abstract

To make temperature of a battery easily raise during external charging even when outside temperature is low.SOLUTION: A battery 10 is mounted on a floor 1a of an electric vehicle 1. The battery 10 becomes, when a charge plug 40 is connected with a charge connector 30, chargeable from the external. An ECU 100 lowers, when outside temperature detected by an outside air temperature sensor 61 is a prescribed temperature β or less at the time of the external charging of the battery 10, a vehicle height of the electric vehicle 1 through a height control system 20. Thereby, a distance between the floor 1a and a road surface is shortened, heat of the battery 10 cooled by the outside temperature is reduced.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to electric vehicles. [Background technology]

[0002] Japanese Patent Laid-Open Publication No. 2018-7428 (Patent Document 1) discloses a battery charging system for an electric vehicle that can charge the battery from an external power source. In this battery charging system, when the battery temperature is low at the start time of external charging, a heater that heats the battery is energized to heat the battery to a target heating temperature. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-7428 A Summary of the Invention [Problem to be solved by the invention]

[0004] Even if the battery is heated when the battery temperature is low as disclosed in Patent Document 1, if the outside air temperature is low, the heat of the battery is taken away by the outside air, making it difficult to heat the battery.

[0005] An object of the present disclosure is to prevent the battery from becoming difficult to heat up during external charging, even when the outside air temperature is low. [Means for solving the problem]

[0006] The electric vehicle according to the present disclosure includes a battery that is mounted on a floor and capable of being charged externally, a suspension device that is capable of adjusting the vehicle height, and a control device that controls the suspension device. When an outside air temperature is equal to or lower than a predetermined temperature during external charging, the control device controls the suspension device so that the vehicle height is lower than when the outside air temperature is higher than the predetermined temperature.

[0007] The battery is mounted on the floor of the electric vehicle, and when the outside air temperature is low, heat from the battery is carried away by the outside air between the floor and the road surface. With this configuration, when the battery is externally charged, the vehicle height of the electric vehicle is lower when the outside air temperature is equal to or lower than a predetermined temperature compared to when the outside air temperature is higher than the predetermined temperature, and the distance between the floor and the road surface (ground) is shortened. When the distance between the floor and the road surface is shortened, less outside air passes between the floor and the road surface (or is present between the floor and the road surface), and less heat is carried away from the battery. This makes it possible to prevent the battery from becoming difficult to warm up during external charging, even when the outside air temperature is low.

[0008] The battery only needs to be mounted on the floor of the electric vehicle, and may be on the inside or outside of the vehicle cabin on the floor. The electric vehicle of the present disclosure may or may not be equipped with a heating device for heating the battery. When a heating device is not provided, heat generated by polarization heat (resistance heating) of the battery during external charging can be effectively used. When a heating device is provided, the energy consumption of the heating device can be reduced. Effect of the Invention

[0009] According to the present disclosure, even when the outside air temperature is low, it is possible to prevent the battery from becoming difficult to heat up during external charging. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram showing a schematic overall configuration of an electric vehicle according to an embodiment of the present invention; [Diagram 2] 5 is a flowchart showing an example of a process for vehicle height control during external charging, which is executed by an ECU. [Diagram 3] 1A and 1B are diagrams illustrating the operation of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference characters, and the description thereof will not be repeated.

[0012] Fig. 1 is a diagram showing a schematic overall configuration of an electric vehicle 1 according to the present embodiment. The electric vehicle 1 is equipped with a battery 10 that stores electric power for running. The electric vehicle 1 is configured to be able to run using the electric power stored in the battery 10. In the present embodiment, the electric vehicle 1 is an electric vehicle that does not have an engine (internal combustion engine), but may also be a plug-in hybrid vehicle that has an engine.

[0013] The electric vehicle 1 includes a suspension 2 having a vehicle height adjustment device 20. The vehicle height adjustment device 20 includes a compressor 21, a dryer 22, a control valve 23, an air spring (pneumatic cylinder) 24, and an air tube 25. The air spring 24 is a suspension spring of the suspension 2 provided on each wheel of the electric vehicle 1. When air is compressed by the compressor 21, moisture in the compressed air is removed by the dryer 22, and the compressed air is supplied to the air spring 24 via the air tube 25. The vehicle height of the electric vehicle 1 is adjusted by supplying and discharging the compressed air inside (chamber) of the air spring 24 by the control valve 23. When compressed air is supplied to the air spring 24, the vehicle height of the electric vehicle 1 increases. When compressed air is discharged from the air spring 24, the vehicle height of the electric vehicle 1 decreases.

[0014] Battery 10 is an assembled battery in which a plurality of secondary batteries (for example, lithium ion batteries) are connected in series, and can be charged (external charging) using a power source external to the vehicle. Battery 10 is mounted on a floor (floor panel) 1a of electric vehicle 1, and may be mounted on the interior side of the vehicle cabin of electric vehicle 1, or on the exterior side of the vehicle cabin of electric vehicle 1. In this embodiment, a space for mounting battery 10 is formed in floor 1a, and battery 10 is mounted on the exterior side of the vehicle cabin (under the floor).

[0015] The electric vehicle 1 includes a charging connector 30, which is connected to the battery 10 by a power line via a charging circuit 31. When a charging plug 40 is connected to the charging connector 30, the battery 10 can be externally charged. The charging connector 30 is provided at the end of a charging cable 41 that is connected to an external power source (not shown). When the external power source is an AC power source, the charging circuit 31 includes a charger that converts AC power into DC power.

[0016] The battery 10 can be heated by using a thermal management circuit 200. The thermal management circuit 200 includes a battery circuit 50, a refrigeration circuit 60, and a heating circuit 70. The refrigeration circuit 60 is a refrigeration cycle including a compressor, a condenser, an expansion valve, an evaporator, etc., and is used for cooling the vehicle air conditioner. The refrigerant of this refrigeration cycle (refrigeration circuit 60) flows into a chiller 51 of the battery circuit 50 via an expansion valve.

[0017] The heating circuit 70 is used for heating the vehicle air conditioner by circulating a heat medium. The heating circuit 70 includes a heater (electric heater), a heater core, a pump, etc., and the heat medium of the heating circuit 70 can also be circulated to a high-temperature radiator 71. The heat medium of the heating circuit 70 exchanges heat with a condenser of the refrigeration circuit 60.

[0018] The battery circuit 50 cools and heats (heats) the battery 10 by circulating the heat medium. The battery circuit 50 functions as a cooling device and a heating device for the battery 10. The battery circuit 50 includes a chiller 51, a pump 52, a three-way valve 53, a battery heater (electric heater) 54, and a low-temperature radiator 55. When cooling the battery 10, the heat medium cooled (has undergone heat exchange) in the chiller 51 absorbs heat from the battery 10 as it passes through the battery 10, thereby cooling the battery 10. When heating the battery 10, the battery heater 54 is energized, and the heat medium is heated by the heat generated by the battery heater 54. The heat exchange between the heat medium and the battery 10 causes the battery 10 to heat up (become heated).

[0019] Also, in addition to or instead of the battery heater 54, the battery 10 can be heated using a heater for heating in the heating circuit 70. In this case, the heating circuit 70 is controlled so that the heat medium heated by the heater for heating passes through the high-temperature radiator 71. The three-way valve 53 is controlled so that the heat medium discharged from the pump 52 circulates through the low-temperature radiator 55. Heat exchange occurs between the high-temperature radiator 71 and the low-temperature radiator 55, the temperature of the heat medium in the battery circuit 50 increases, and the temperature of the battery 10 is raised. At this time, if the battery heater 54 is energized, the battery 10 can be heated using the heater for heating in addition to the battery heater 54. If the battery heater 54 is stopped being energized, the battery 10 can be heated using the heater for heating instead of the battery heater 54. In this way, even if the configuration does not include the battery heater 54, the battery 10 can be heated using the heater for heating.

[0020] The electric vehicle 1 includes a control device (ECU: Electronic Control Unit) 100. The ECU 100 is configured to perform charge / discharge control of the battery 10, vehicle height adjustment control of the electric vehicle 1, etc. Detection signals of an outside air temperature sensor 61 that detects an outside air temperature TA and a vehicle height sensor 62 that detects the vehicle height H of the electric vehicle 1 are input to the ECU 100.

[0021] The monitoring module 11 includes various sensors that detect the state of the battery 10 (for example, the voltage VB, the current IB, and the temperature TB) and outputs the detection results to the ECU 150. The monitoring module 11 may be configured to calculate the SOC (State Of Charge) of the battery 10 from the detection results of these sensors.

[0022] When external charging of the battery 10 is performed, if the temperature (battery temperature) TB of the battery 10 is low, the internal resistance is large, and there is a concern that charging efficiency may deteriorate. For this reason, when external charging is performed, it is preferable to raise the temperature of the battery 10 when the battery temperature TB is low.

[0023] In the case where the battery 10 is mounted on the floor 1a of the electric vehicle 1, if the outside air temperature is low when the battery 10 is being heated, the heat of the battery 10 is carried away by the outside air between the floor and the road surface, and the temperature of the battery 10 may not be raised efficiently. In this embodiment, when the outside air temperature is low during external charging, the vehicle height of the electric vehicle 1 is lowered to reduce the distance between the floor 1a and the road surface, thereby reducing the amount of outside air passing between the floor 1a and the road surface (or existing between the floor 1a and the road surface). This reduces the heat carried away from the battery 10 by the outside air.

[0024] 2 is a flowchart showing an example of a process for vehicle height control during external charging, which is executed by ECU 100. This flowchart is started when charging plug 40 is connected to charging connector 30 and external charging is started. Note that, in the case of timer charging, the process is executed when a set time arrives and external charging is started.

[0025] First, in step (hereinafter, step is abbreviated as "S") 10, it is determined whether or not the battery temperature TB is equal to or lower than a predetermined temperature α. The predetermined temperature α may be, for example, a value at which the battery 10 is heated using the battery circuit 50 when the battery temperature TB is equal to or lower than the predetermined temperature α. If the battery temperature TB is equal to or lower than the predetermined temperature α, a positive determination is made and the process proceeds to S11. If the battery temperature TB is higher than the predetermined temperature α, a negative determination is made and the process proceeds to S13.

[0026] In S11, it is determined whether the outside air temperature TA is equal to or lower than a predetermined temperature β. The predetermined temperature β may be "-30° C." If the outside air temperature TA is equal to or lower than the predetermined temperature β, a positive determination is made and the process proceeds to S12. If the outside air temperature TA is higher than the predetermined temperature β, a negative determination is made and the process proceeds to S13.

[0027] In S12, the vehicle height is lowered and flag F is set to 1. The vehicle height adjustment device 20 controls the vehicle height H to the minimum vehicle height Hlow. The initial value (default value) of flag F is 0. The minimum vehicle height Hlow is the lowest vehicle height at which the undercarriage components of the floor 1a of the electric vehicle 1 do not interfere with the road surface. In the following S13, it is determined whether external charging has ended. If external charging has not ended, a negative determination is made and the process returns to S10. If external charging has ended, the process proceeds to S14.

[0028] In S14, it is determined whether or not flag F is 1. If flag F is 1, the process proceeds to S15, and if flag F is 0, the current routine is terminated. In S15, the vehicle height is restored (raised) and flag F is set to 0, and the current routine is terminated. The vehicle height adjusting device 20 controls the vehicle height H to the normal vehicle height Hnormal. The normal vehicle height Hnormal is, for example, the vehicle height when the electric vehicle 1 is running.

[0029] FIG. 3 is a diagram for explaining the operation of this embodiment. FIG. 3(A) shows a case where the vehicle height H is the normal vehicle height Hnormal, and FIG. 3(B) shows a case where the vehicle height H is the minimum vehicle height Hlow. As shown in FIG. 3(B), when the vehicle height H becomes the minimum vehicle height Hlow, the distance between the floor 1a and the road surface becomes shorter, and the amount of outside air passing between the floor 1a and the road surface (or existing between the floor 1a and the road surface) becomes smaller, and the heat carried away from the battery 10 becomes less. As a result, even when the outside air temperature TA is low, it is possible to suppress the battery 10 from becoming difficult to increase in temperature during external charging.

[0030] In the above embodiment, the temperature of the battery 10 is increased by the battery circuit 50 (temperature increasing device), but the battery circuit 50 may be omitted. In this case, heat generated by polarization heat generation of the battery 10 during external charging can be effectively used.

[0031] In the above embodiment, the vehicle height is adjusted by the air spring 24, but other configurations may be used as long as they are capable of adjusting the vehicle height of the electric vehicle 1. For example, a hydraulic suspension may be used.

[0032] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0033] 1 electric vehicle, 2 suspension, 10 battery, 20 height adjustment device, 30 charging connector, 40 charging plug, 50 battery circuit, 60 refrigeration circuit, 70 heating circuit, 100 control unit (ECU), 200 thermal management circuit.

Claims

[Claim 1] A battery that is mounted on the floor and can be charged externally; A suspension device capable of adjusting the vehicle height; A control device for controlling the suspension device, The control device controls the suspension device to lower the vehicle height when an outside air temperature is equal to or lower than a predetermined temperature during external charging, compared to when the outside air temperature is higher than the predetermined temperature.

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