Battery cooling method, battery cooling circuit, and, battery cooling control device

Abstract

To provide a battery cooling method, a battery cooling circuit and a battery cooling control device which efficiently suppress deterioration of the battery by decreasing temperature of a battery greatly by electric power consumption which is less than before.SOLUTION: The battery cooling method is for cooling a battery 12, in an electric vehicle that is provided with the battery 12 and a battery cooling circuit (101) which circulates refrigerant liquid into the battery 12 using a pump 19. In the battery cooling method, an outside air temperature Tenv that is a temperature of outside air is obtained, a battery temperature Tbat that is a temperature of the battery 12 is obtained, a proper temperature range in which the battery 12 hardly deteriorates is set for the battery temperature Tbat, and when the battery temperature Tbat is within the proper temperature range and when the outside air temperature Tenv is lower than the battery temperature Tbat, refrigerant liquid is circulated into a radiator 13 that exchanges heat with outside air and the battery 12, and thus the battery 12 is cooled.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a battery cooling method, a battery cooling circuit, and a battery cooling device for cooling a battery mounted on a vehicle. [Background technology]

[0002] Patent Document 1 discloses a technique for lowering the temperature and SOC of a battery mounted on a hybrid vehicle in order to prevent deterioration of the battery. Specifically, Patent Document 1 describes that when the battery temperature or SOC is high, the SOC is lowered by operating an air conditioner, and the battery temperature is lowered by blowing air cooled by the air conditioner to the battery using a battery fan. Patent Document 1 also mentions that when the battery temperature is not so high and the SOC is to be lowered slightly, only the battery fan is driven. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4589872 Summary of the Invention [Problem to be solved by the invention]

[0004] In hybrid vehicles and other electrically powered vehicles, it is required to prevent battery degradation as much as possible even when the battery is repeatedly charged and discharged.

[0005] Generally, factors that cause a battery to deteriorate include temperature and the accumulated charge / discharge amount. Specifically, when the temperature of a battery rises due to charging or discharging, the performance of the battery deteriorates. Furthermore, the more the battery is repeatedly charged and discharged, and the greater the accumulated amount (accumulated charge / discharge amount), the more the performance deteriorates. However, since the accumulated charge / discharge amount is highly dependent on the specific or actual usage of the electric vehicle, it is not easy for the electric vehicle to actively control (limit) the accumulated charge / discharge amount in order to suppress battery deterioration. For this reason, in electric vehicles, the battery performance deterioration is suppressed mainly by managing the temperature of the battery so that the battery is used within an appropriate temperature range where performance deterioration is unlikely to occur. For example, when the temperature of the battery is about to rise beyond the appropriate temperature range, the battery is cooled using an air conditioning system or the like.

[0006] However, cooling by an air conditioning system or the like requires a large amount of power. The power required for cooling by an air conditioning system or the like is supplied from the battery, which is the object to be cooled. For this reason, when cooling a battery using an air conditioning system or the like, even if the temperature of the battery can be lowered, the cumulative charge / discharge amount increases. In other words, when deterioration due to temperature rise and deterioration due to an increase in the cumulative charge / discharge amount are taken into consideration comprehensively, the result may be that battery deterioration cannot be efficiently suppressed.

[0007] Therefore, in order to efficiently suppress battery deterioration while taking into consideration the temperature and the accumulated charge / discharge amount, it is necessary to reduce the battery temperature while suppressing the battery's power consumption. In other words, there is a demand for a cooling technology that can significantly reduce the battery temperature while consuming less power than before.

[0008] The present invention aims to provide a battery cooling method, a battery cooling circuit, and a battery cooling device that can efficiently suppress battery deterioration by lowering the battery temperature with less power consumption than conventional methods. [Means for solving the problem]

[0009] One aspect of the present invention is a battery cooling method for cooling a battery in an electric vehicle having a battery and a battery cooling circuit that circulates a refrigerant liquid through the battery using a pump. In this battery cooling method, an outside air temperature, which is the temperature of the outside air, is obtained, and a battery temperature, which is the temperature of the battery, is obtained. Then, when the outside air temperature is lower than the battery temperature, the refrigerant liquid is circulated through a radiator that exchanges heat with the outside air and the battery, thereby cooling the battery. Effect of the Invention

[0010] According to the present invention, it is possible to provide a battery cooling method, a battery cooling circuit, and a battery cooling device that efficiently suppress battery deterioration by significantly lowering the battery temperature with less power consumption than conventional methods. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic configuration of a cooling system. [Diagram 2] FIG. 2 is an explanatory diagram showing the configuration of the first mode. [Diagram 3] FIG. 3 is an explanatory diagram showing the configuration of the second mode. [Figure 4] FIG. 4 is an explanatory diagram showing the configuration of the third mode. [Diagram 5] FIG. 5 is an explanatory diagram showing a configuration of the fourth mode. [Figure 6] FIG. 6 is an explanatory diagram showing a configuration of the fifth mode. [Figure 7] FIG. 7 is a flowchart showing a switching manner among the first mode, the second mode, and the third mode. [Figure 8] FIG. 8 is a flowchart showing the selection and switching between the fourth mode and the fifth mode. [Figure 9] FIG. 9 is a graph showing a schematic diagram of the circadian changes in the outside air temperature and the battery temperature. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] [Embodiment] 1 is an explanatory diagram showing a schematic configuration of a cooling system 100. The cooling system 100 is a system that is mounted on an electric vehicle such as an electric car or a hybrid car, and cools parts of the electric vehicle whose temperature needs to be controlled. In principle, the cooling system 100 is a system for cooling parts that generate heat, but the cooling system 100 may warm (heat) the target parts as necessary in order to maintain the temperature of the target parts.

[0014] As shown in FIG. 1, the cooling system 100 is a system that cools an electric powertrain 11 and a battery 12, which are main objects to be cooled in an electric vehicle, and includes a cooling circuit 101 and a controller .

[0015] The electric powertrain 11 is composed of, for example, an electric motor, an inverter for driving the electric motor, and a mechanism for transmitting torque generated by the electric motor to wheels. The electric powertrain may also include a generator and an internal combustion engine for driving the generator. Of these, the parts to be cooled by the cooling system 100 are, for example, the electric motor, the inverter, the generator, and the internal combustion engine.

[0016] The battery 12 is, for example, a secondary battery such as a lithium ion battery, and can repeatedly be charged and discharged (to supply power to the electric power train 11, etc.) The battery 12 is a so-called high-voltage battery that stores power for driving an electric vehicle.

[0017] The temperature of the battery 12 increases due to charging and discharging. If the temperature exceeds the appropriate temperature range (hereinafter, the battery temperature T bat When the battery temperature T batWhen the temperature drops, the internal resistance increases and the actual capacity drop becomes significant. The appropriate temperature range in which deterioration due to temperature rise and capacity drop due to temperature drop are unlikely to occur is, for example, from about 0°C to about 45°C.

[0018] Therefore, the battery temperature T bat The battery 12 is cooled or heated by the cooling system 100 so that the battery temperature T bat (Hereinafter, the upper limit T batUL ), and the battery temperature T bat (Hereinafter, the lower limit T batLL The upper limit T batUL is set to a value lower than the upper limit of the appropriate temperature range (e.g., 45° C.). batLL is set to a value higher than the lower limit of the appropriate temperature range (eg, 0° C.), for example.

[0019] The cooling circuit 101 functions as an electric powertrain cooling circuit that cools the electric powertrain 11, and also functions as a battery cooling circuit that cools the battery 12. Specifically, the cooling circuit 101 includes a refrigerant liquid circulation circuit 112 and a refrigerant gas circulation circuit 113.

[0020] The refrigerant liquid circulation circuit 112 is a circuit that cools the electric powertrain 11 and the battery 12 by circulating water or other liquid (hereinafter referred to as refrigerant liquid). The electric powertrain 11 and the battery 12 are each covered with a water jacket, and the refrigerant liquid exchanges heat with the main bodies of the electric powertrain 11 and the battery 12 by flowing through each water jacket. In Fig. 1, paths through which the refrigerant liquid can circulate are indicated by solid lines.

[0021] The refrigerant liquid circulation circuit 112 includes a radiator 13, a chiller 14, and a heater 15 as elements for controlling the temperature of the refrigerant liquid.

[0022] The radiator 13 is a heat exchanger that exchanges heat between the outside air and the refrigerant liquid. env The temperature of the refrigerant liquid (hereinafter referred to as the refrigerant liquid temperature T ref As long as the refrigerant liquid temperature T ref When the electric vehicle is moving and is exposed to wind due to traveling, the heat exchange performance of the radiator 13 is improved. That is, when there is wind due to traveling, the refrigerant liquid in the radiator 13 is easily cooled.

[0023] The chiller 14 is a heat exchanger that exchanges heat between the refrigerant gas in the refrigerant gas circulation circuit 113 (described later) and the refrigerant liquid. In this embodiment, the refrigerant liquid loses heat to the refrigerant gas as it flows through the chiller 14. Therefore, the refrigerant liquid temperature T ref decreases.

[0024] The heater 15 heats the refrigerant liquid flowing through the battery 12. For example, the battery temperature T bat is the lower limit T batLL When the battery temperature T is lower than the battery temperature T , the heater 15 heats the refrigerant liquid flowing through the battery 12. This allows the battery 12 to be maintained at a temperature higher than the lower limit of the appropriate temperature range. The heater 15 is, for example, a PTC (Positive Temperature Coefficient) heater. In this embodiment, the battery temperature T bat is equal to or higher than the lower limit of the appropriate temperature range. Therefore, in this embodiment, the heater 15 is not used.

[0025] The refrigerant liquid circulation circuit 112 includes valves 16 and 17 as elements for switching the circulation path (flow path) of the refrigerant liquid.

[0026] The valve 16 switches whether or not to circulate the refrigerant liquid through the electric powertrain 11. When the ignition (power switch) is on and the electric vehicle is in a state in which it can run, the valve 16 switches the circulation path of the refrigerant liquid so that the refrigerant liquid that has circulated through the radiator 13 flows into the electric powertrain 11. In other words, in a situation in which it is necessary to cool the electric powertrain 11, the valve 16 switches the circulation path of the refrigerant liquid so that the refrigerant liquid circulates between the electric powertrain 11 and the radiator 13.

[0027] The valve 17 switches the circulation destination of the refrigerant liquid supplied to the battery 12 between the radiator 13 and the chiller 14 .

[0028] In this embodiment, when the vehicle is traveling under high load or when the battery 12 is being rapidly charged, the battery temperature T bat is the upper limit T batUL In the above-described situation, in a scene where the battery 12 needs to be cooled (a scene where cooling of the battery is essential), the valve 17 switches the circulation path of the refrigerant liquid flowing through the battery 12 so that the refrigerant liquid is circulated to the chiller 14. That is, the battery temperature T bat When cooling of the battery 12 becomes necessary to maintain the battery 12 within an appropriate temperature range, the valve 17 switches the circulation path of the refrigerant liquid so that it circulates through the battery 12 and the chiller 14.

[0029] On the other hand, the battery temperature T bat is the upper limit T batUL Battery temperature T bat In a situation where the battery temperature T is within the appropriate temperature range but the deterioration of the battery 12 can be suppressed by cooling the battery 12 in advance, the valve 17 switches the circulation path of the refrigerant liquid flowing through the battery 12 so that the refrigerant liquid is circulated to the radiator 13. That is, in this embodiment, batFrom this perspective, cooling of the battery 12 is not essential, but there are cases where the battery 12 is cooled preventively to suppress deterioration of the battery 12. In this case, the valve 17 switches the circulation path of the refrigerant liquid so that it circulates between the battery 12 and the radiator 13.

[0030] In the following, the battery temperature T bat is the upper limit T batUL When the battery temperature T bat is the upper limit T batUL Preventive cooling refers to cooling the battery 12 preventively when the battery temperature is lower than the required temperature in order to efficiently suppress future performance deterioration of the battery 12. When mandatory cooling is performed, the refrigerant liquid for cooling the battery 12 is circulated to the chiller 14, and when preventive cooling is performed, the refrigerant liquid for cooling the battery 12 is circulated to the radiator 13.

[0031] The refrigerant liquid circulation circuit 112 includes pumps 18 and 19 as elements for circulating the refrigerant liquid.

[0032] The pump 18 circulates the refrigerant liquid through the electric powertrain 11 and the radiator 13. Therefore, the pump 18 is disposed between the electric powertrain 11 and the radiator 13 in the circulation path of the refrigerant liquid. Note that the pump 18 can change the flow rate of the refrigerant liquid circulating through the electric powertrain 11 and the radiator 13 (the amount of refrigerant liquid supplied to the electric powertrain 11) by adjusting the output. The output of the pump 18 is adjusted appropriately according to the temperature of the electric powertrain 11, etc.

[0033] The pump 19 circulates the refrigerant liquid between the battery 12 and the radiator 13, or between the battery 12 and the chiller 14. Therefore, the pump 19 is disposed in the circulation path of the refrigerant liquid between the battery 12 and the radiator 13 and between the battery 12 and the chiller 14. Note that the pump 19 can change the flow rate of the refrigerant liquid circulating between the battery 12 and the radiator 13 or the chiller 14 (the amount of refrigerant liquid supplied to the battery 12) by adjusting the output.

[0034] When the battery 12 is cooled by the refrigerant liquid circulating through the battery 12 and the chiller 14, i.e., when essential cooling is performed, the output of the pump 19 is increased by a factor of 10. bat It will be adjusted appropriately depending on the situation.

[0035] When the battery 12 is cooled by the refrigerant liquid circulating through the battery 12 and the radiator 13, i.e., when preventive cooling is performed, the output of the pump 19 is increased by a factor of 10. bat In addition, the output of the pump 19 is adjusted depending on whether the electric vehicle is running or not, or whether the ignition is on and the electric vehicle is in a runnable state or not. In this embodiment, the output of the pump 19 is adjusted so that the flow rate of the refrigerant liquid when the ignition is off and the electric vehicle is in a non-runnable state is smaller than the flow rate of the refrigerant liquid when the ignition is on and the electric vehicle is in a runnable state. That is, when preventive cooling is performed, when the electric vehicle is in a runnable state, the output of the pump 19 is suppressed and the amount of refrigerant liquid supplied to the battery 12 (amount of refrigerant liquid supplied per unit time) is reduced compared to when the electric vehicle is in a runnable state.

[0036] Note that the drivable state means a state in which the electric vehicle can run if the driver operates the accelerator or the like. In the present embodiment, the drivable state includes a state in which the electric vehicle is actually running (a running state). Further, the non-drivable state means a state in which, for example, the motor which is a drive source is not energized, and the electric vehicle cannot run even if the driver operates the accelerator or the like. In the present embodiment, the non-drivable state includes not only a state in which power is not supplied to any part of the electric vehicle, but also a state in which parts other than the drive system of the electric vehicle (such as a pump operating at low power) can be used.

[0037] The refrigerant gas circulation circuit 113 is constituted by a compression / expansion unit 21, a condenser 22, and a chiller 14, and is a circuit that generates a temperature difference between the chiller 14 and the condenser 22 by the latent heat when expanding and compressing the refrigerant gas. In FIG. 1, the circulation path of the refrigerant gas is indicated by a double line.

[0038] The compression / expansion unit 21 is a unit including a compressor that compresses the refrigerant gas, an expansion valve that expands the refrigerant gas, and the like.

[0039] The refrigerant gas compressed by the compressor and having become high temperature and high pressure is sent to the condenser 22. In the present embodiment, the condenser 22 is a so-called air-cooled condenser, and cools and condenses the refrigerant gas by heat exchange with the outside air. The refrigerant gas condensed by the condenser 22 is introduced into the expansion valve. The expansion valve diffuses and expands the condensed refrigerant gas and introduces it into the chiller 14. As a result, the condenser 22 becomes relatively high temperature, and the chiller 14 becomes relatively low temperature. Further, in the chiller 14, the refrigerant gas takes the heat of the refrigerant liquid flowing through the refrigerant liquid circulation circuit 112. Then, the refrigerant gas that has taken the heat from the refrigerant liquid flowing through the refrigerant liquid circulation circuit 112 is introduced into the compressor. As a result, overall, the heat that the refrigerant liquid had is discharged to the outside air in the condenser 22. Therefore, when the circulation destination of the refrigerant liquid flowing through the battery 12 is the chiller 14, the battery 12 is cooled by the refrigerant gas circulation circuit 113.

[0040] However, the compressor is driven by the power of the battery 12 and consumes a large amount of power compared to the pumps 18 and 19. Therefore, cooling of the battery 12 using the refrigerant gas circulation circuit 113 is performed at a temperature T bat However, the cumulative charge and discharge amount tends to increase.

[0041] The refrigerant gas circulation circuit 113 is also used for air conditioning (particularly cooling) of the vehicle interior. In this case, the refrigerant gas circulation circuit 113 is a part of the air conditioning (cooling) system for the vehicle interior.

[0042] In addition to the above, the cooling circuit 101 includes a grill shutter 23 and a blower fan 24 .

[0043] The grill shutter 23 can be opened and closed freely, and adjusts the outside air introduced through a grill (a mesh-like or slit-like opening) provided on the front of the electric vehicle. Specifically, the grill shutter 23 opens to introduce outside air into the radiator 13 and the condenser 22 when the electric vehicle is running. The grill shutter 23 closes to promote warming up of the electric powertrain 11, etc., or to suppress excessive cooling. In other words, the grill shutter 23 blocks ventilation to the radiator 13 as necessary. Particularly in this embodiment, when preventive cooling of the battery 12 is performed, if the grill shutter 23 was closed, the grill shutter 23 is opened.

[0044] The blower fan 24 sends outside air to the radiator 13 and the condenser 22. In this embodiment, the blower fan 24 operates as necessary when the electric vehicle is stopped or when the electric vehicle is not capable of traveling. That is, when wind caused by running is not introduced into the radiator 13 and the condenser 22, the blower fan 24 operates in order to increase the efficiency of heat exchange between the radiator 13 and the condenser 22 and the outside air. Even when the electric vehicle is running and wind caused by running is available, if the amount of wind introduced into the radiator 13 and the condenser 22 is insufficient, the blower fan 24 can be operated to increase the efficiency of heat exchange between the radiator 13 and the condenser 22 and the outside air.

[0045] The output of the blower fan 24 can be adjusted to change the amount of air sent to the radiator 13 and the condenser 22. In particular, when preventive cooling is performed when the electric vehicle is in a non-travelable state, it is preferable to operate the blower fan 24. In addition, it is preferable to adjust the output of the blower fan 24 so that the amount of air sent when the electric vehicle is in a non-travelable state is smaller than the amount of air sent when the electric vehicle is in a travelable state.

[0046] The controller 102 is a device that controls (manages) the temperatures of the electric power train 11 and the battery 12 by comprehensively controlling the operations of each part that constitutes the cooling circuit 101. Particularly in this embodiment, the controller 102 functions as a battery cooling control device that controls the cooling of the battery 12. The controller 102 is configured by, for example, one or more computers. A program for the controller 102 to control the cooling of the battery 12 is a battery cooling control program.

[0047] The controller 102 can appropriately acquire or calculate parameters that need to be referred to for controlling the temperatures of the electric powertrain 11 and the battery 12. The controller 102 can appropriately acquire information such as the on / off state of the ignition (distinguishing between a running state and a non-running state) and whether the electric vehicle is running or not. In addition, for example, the controller 102 can acquire the temperature of the electric powertrain 11, the battery temperature T bat , outside temperature T env , and the refrigerant liquid temperature T ref The above can be appropriately acquired or calculated using a temperature sensor (not shown).

[0048] In this embodiment, the controller 102 controls the temperature of the battery 12 based on the battery temperature T bat , outside temperature T env , and the current refrigerant liquid temperature T ref (Hereafter, current refrigerant liquid temperature T ref-C (called "information").

[0049] The controller 102 also detects the battery temperature T bat and outside temperature T env Based on this, when the refrigerant liquid is circulated to the battery 12 and the radiator 13 (i.e., when preventive cooling is performed), the temperature of the refrigerant liquid to be supplied to the battery 12 (hereinafter referred to as the supply refrigerant liquid temperature T ref-est In this embodiment, the controller 102 calculates (estimates) the outside air temperature T env and the current refrigerant liquid temperature T ref-C and the supply refrigerant liquid temperature T ref-est The controller 102 stores in advance a supply refrigerant liquid temperature estimation map (not shown) that associates the supply refrigerant liquid temperature with the outside air temperature T env and the current refrigerant liquid temperature T ref-C Based on the supply refrigerant liquid temperature T ref-est can be calculated.

[0050] When cooling the electric powertrain 11, the battery 12, or both, the controller 102 operates the cooling circuit 101 in five operating modes: a first mode, a second mode, a third mode, a fourth mode, and a fifth mode.

[0051] Fig. 2 is an explanatory diagram showing the configuration of the first mode. In Fig. 2, the paths through which the refrigerant liquid circulates in the first mode are shown by solid lines, and the paths through which the flow of the refrigerant liquid or the like is stopped are shown by dashed lines.

[0052] 2, the first mode is a mode in which only the electric powertrain 11 is cooled out of the electric powertrain 11 and the battery 12. For this reason, the controller 102 controls the valves 16, 17 and the pump 18 to circulate the refrigerant liquid to the electric powertrain 11 and the radiator 13 and to stop the circulation of the refrigerant liquid to the battery 12. As a result, the electric powertrain 11 is cooled by exchanging heat with outside air via the radiator 13.

[0053] The first mode is selected, for example, when the electric vehicle is in a state where it can run or when the electric vehicle is actually running and cooling of the electric powertrain 11 is necessary, but cooling of the battery 12 (essential cooling) is not necessary and preventive cooling is not (cannot be) performed.

[0054] The controller 102 adjusts the output of the pump 18 in accordance with the temperature of the electric powertrain 11 and the like.

[0055] Fig. 3 is an explanatory diagram showing the configuration of the second mode. In Fig. 3, solid lines indicate paths through which the refrigerant liquid or refrigerant gas circulates in the second mode, and dashed lines indicate paths through which the flow of the refrigerant liquid is stopped.

[0056] 3, the second mode is a mode in which both the electric powertrain 11 and the battery 12 are cooled separately (the battery 12 must be cooled). Specifically, the controller 102 controls the valve 16 and the pump 18 to circulate the refrigerant liquid through the electric powertrain 11 and the radiator 13. As a result, the electric powertrain 11 is cooled by exchanging heat with outside air via the radiator 13.

[0057] On the other hand, the controller 102 controls the valve 17 and the pump 19 to circulate the refrigerant liquid to the battery 12 and the chiller 14, independently of the circulation of the refrigerant liquid in the electric power train 11 and the radiator 13. The controller 102 also operates the compressor of the compression / expansion unit 21 to circulate the refrigerant gas to the refrigerant gas circulation circuit 113. This causes the refrigerant liquid circulating through the battery 12 via the chiller 14 to be cooled. As a result, the battery 12 is cooled. That is, in the second mode, the battery 12 is cooled in exchange for power consumption in the compressor of the compression / expansion unit 21.

[0058] The second mode is selected when the electric powertrain 11 needs to be cooled, for example, when the electric vehicle is running, and further when the battery 12 needs to be cooled (essential cooling). For example, the second mode is selected when the electric vehicle runs under high load or after the battery 12 is quickly charged.

[0059] The controller 102 adjusts the output of the pump 18 in accordance with the temperature of the electric power train 11, etc. Also, the controller 102 adjusts the output of the pump 18 in accordance with the temperature of the battery T bat The cooling speed of the battery 12 can be changed by adjusting the output of the pump 19 according to the battery 12. In this embodiment, when the second mode is selected, the controller 102, in principle, adjusts the output of the pump 19 to the maximum to cool the battery 12 as quickly as possible. In addition, the refrigerant liquid circulating through the battery 12 and the chiller 14 also circulates through the heater 15, but in a scene where the cooling circuit 101 is operated in the second mode to cool the battery 12, the controller 102 turns off the heater 15.

[0060] Fig. 4 is an explanatory diagram showing the configuration of the third mode. In Fig. 4, solid lines indicate paths through which the refrigerant liquid or refrigerant gas circulates in the third mode, and dashed lines indicate paths through which the flow of the refrigerant liquid is stopped.

[0061] As shown in FIG. 4, the third mode is a mode in which the battery 12 is cooled alone (mandatory cooling) among the electric power train 11 and the battery 12. For this reason, the controller 102 controls the valves 16, 17 and the pump 19 to circulate the refrigerant liquid to the battery 12 and the chiller 14 and to stop the circulation of the refrigerant liquid to the electric power train 11. The controller 102 also operates the compressor of the compression / expansion unit 21 to circulate the refrigerant gas to the refrigerant gas circulation circuit 113. This causes the refrigerant liquid circulating through the battery 12 via the chiller 14 to be cooled. As a result, the battery 12 is cooled. That is, in the third mode, the battery 12 is cooled in exchange for power consumption in the compressor of the compression / expansion unit 21.

[0062] The third mode is selected when the battery 12 must be cooled (essential cooling) in a case where cooling of the electric powertrain 11 is not required, such as when the ignition of the electric vehicle is off (non-driving state). The third mode is selected, for example, when the electric vehicle is stopped with the temperature of the battery 12 still elevated due to power consumption for driving, or when the battery 12 is to be rapidly charged.

[0063] The controller 102 may, for example, detect the battery temperature T bat The cooling speed of the battery 12 can be changed by adjusting the output of the pump 19 according to the battery 12. In this embodiment, when the third mode is selected, the controller 102, in principle, adjusts the output of the pump 19 to the maximum to cool the battery 12 as quickly as possible. Furthermore, the refrigerant liquid circulating through the battery 12 and the chiller 14 also circulates through the heater 15, but in a scene where the cooling circuit 101 is operated in the third mode to cool the battery 12, the controller 102 turns off the heater 15.

[0064] Fig. 5 is an explanatory diagram showing the configuration of the fourth mode. In Fig. 5, the paths through which the refrigerant liquid circulates in the fourth mode are shown by solid lines, and the paths through which the flow of the refrigerant liquid or refrigerant gas is stopped are shown by dashed lines.

[0065] As shown in FIG. 5, the fourth mode is a mode in which both the electric powertrain 11 and the battery 12 are cooled (preventive cooling is performed for the battery 12). For this reason, the controller 102 controls the valves 16, 17 and the pumps 18, 19 to circulate the refrigerant liquid to the electric powertrain 11 and the radiator 13, and also to circulate the refrigerant liquid to the battery 12 and the radiator 13. In addition, the controller 102 stops the compressor of the compression / expansion unit 21 to stop the circulation of the refrigerant gas in the refrigerant gas circulation circuit 113. As a result, the electric powertrain 11 is cooled by heat exchange with the outside air via the radiator 13. In addition, since the power consumption of the pump 19 is small compared to the power consumption of the compressor, the battery 12 is also cooled substantially by heat exchange with the outside air via the radiator 13.

[0066] In the fourth mode, when the ignition of the electric vehicle is on (in a running state), etc., the electric power train 11 needs to be cooled, and the battery temperature T bat is in the appropriate temperature range, but in order to efficiently suppress future deterioration of the performance of the battery 12, the battery 12 is preventively cooled (when preventive cooling can be performed). For example, when the electric vehicle is in a state where it can run or is actually running and the outside air temperature T env is the battery temperature T bat When the dc voltage is lower than 0.5 V, the fourth mode is selected.

[0067] The controller 102 adjusts the output of the pump 18 in accordance with the temperature of the electric power train 11, etc. Also, the controller 102 adjusts the output of the pump 18 in accordance with the temperature of the battery T bat In response to the above, the output of the pump 19 can be adjusted to change the cooling speed of the battery 12. In this embodiment, when the fourth mode is selected, the controller 102, in principle, adjusts the output of the pump 19 to the maximum, thereby cooling the battery 12 as quickly as possible.

[0068] Furthermore, even when the electric vehicle is in a state where it can run (or is actually running), the controller 102 operates the blower fan 24, thereby improving the efficiency of heat exchange between the refrigerant liquid in the radiator 13 and the outside air. In this embodiment, when the fourth mode is selected, the controller 102 operates the blower fan 24. Furthermore, when operating the blower fan 24, the controller 102 can adjust the output of the blower fan 24. In this embodiment, when the fourth mode is selected, the controller 102 sets the output of the blower fan 24 to a relatively high value. This promotes cooling (preventive cooling) of the battery 12.

[0069] In addition, the refrigerant liquid circulating through the battery 12 and chiller 14 also circulates through the heater 15, but in a scene where the cooling circuit 101 is operated in the second mode to cool the battery 12, the controller 102 turns off the heater 15.

[0070] Fig. 6 is an explanatory diagram showing the configuration of the fifth mode. In Fig. 6, the paths through which the refrigerant liquid circulates in the fifth mode are shown by solid lines, and the paths through which the flow of the refrigerant liquid or refrigerant gas is stopped are shown by dashed lines.

[0071] As shown in FIG. 6, the fifth mode is a mode in which the battery 12 is cooled alone (preventive cooling) among the electric power train 11 and the battery 12. For this reason, the controller 102 controls the valves 16, 17 and the pump 19 to circulate the refrigerant liquid to the battery 12 and the radiator 13 and to stop the circulation of the refrigerant liquid to the electric power train 11. In addition, the controller 102 stops the compressor of the compression / expansion unit 21 to stop the circulation of the refrigerant gas in the refrigerant gas circulation circuit 113. The power consumption of the pump 19 is small compared to the power consumption of the compressor. Therefore, in the fifth mode, the battery 12 is substantially cooled by heat exchange with the outside air via the radiator 13.

[0072] In the fifth mode, when the ignition of the electric vehicle is off (not in a running state), etc., cooling of the electric power train 11 is not required, and the battery temperature T bat is within the appropriate temperature range, but in order to efficiently suppress future deterioration of the performance of the battery 12, the battery 12 is preventively cooled (when preventive cooling can be performed). For example, when the outside temperature T env The natural decrease in the outside temperature T env is the battery temperature T bat When the θ is smaller than θ, the fifth mode is selected.

[0073] The controller 102 may, for example, detect the battery temperature T bat The output of the pump 19 can be adjusted depending on the state of the battery 12, thereby changing the cooling rate of the battery 12. In this embodiment, when the fifth mode is selected, the controller 102 reduces the output of the pump 19 compared to when the fourth mode is selected. That is, when preventively cooling the battery 12, the controller 102 reduces the flow rate of refrigerant liquid supplied to the battery 12 when the electric vehicle is in a non-travelable state, compared to the flow rate of refrigerant liquid supplied to the battery 12 when the electric vehicle is in a travelable state (or is actually traveling). As a result, when the electric vehicle is in a non-travelable state, the battery 12 is cooled (preventively cooled) more slowly than when the electric vehicle is in a travelable state.

[0074] Furthermore, when the fifth mode is selected, that is, when preventive cooling of the battery 12 is performed when the electric vehicle is in a non-travelable state, the controller 102 can operate the blower fan 24. At this time, the controller 102 can arbitrarily adjust the output of the blower fan 24. In this embodiment, when the fifth mode is selected, the controller 102 reduces the output of the blower fan 24 compared to when the fourth mode is selected. That is, the controller 102 reduces the amount of air blown by the blower fan 24 when the electric vehicle is in a non-travelable state, compared to the amount of air blown by the blower fan 24 when the electric vehicle is in a travelable state. As a result, when the electric vehicle is in a non-travelable state, the battery 12 is cooled (preventively cooled) more slowly than when the electric vehicle is in a travelable state.

[0075] In the following, a manner in which the operation mode of the cooling circuit 101 is switched when the electric power train 11 and the battery 12 are cooled in the cooling system 100 configured as described above, and the action thereof will be described.

[0076] Fig. 7 is a flowchart showing a switching manner among the first mode, the second mode, and the third mode. As shown in Fig. 7, in step S10, the controller 102 determines whether the electric vehicle is in a runnable state based on the state of the ignition (IGN) of the electric vehicle.

[0077] If it is determined in step S10 that the ignition is on (ING=ON) and the electric vehicle is in a runnable state, the process proceeds to step S11. In step S11, the controller 102 selects the first mode as the operation mode of the cooling circuit 101. That is, in a scene where cooling of the electric powertrain 11 is required, the operation mode of the cooling circuit 101 is selected to be the first mode in principle.

[0078] Then, in step S12, the controller 102 calculates the battery temperature T bat and the upper limit T batULBy comparing these values, it is determined whether cooling of the battery 12 (mandatory cooling) is required.

[0079] In step S12, the battery temperature T bat is the upper limit T batUL or more, and the battery temperature T bat If it is determined that the battery 12 must be cooled in order to maintain the battery temperature T within the appropriate temperature range, the process proceeds to step S13. Then, in step S13, the controller 102 switches the selection to the second mode and drives the cooling circuit 101 in the second mode. For example, when the battery temperature T bat rises, and the upper limit T batUL When this occurs, the cooling circuit 101 is operated in the second mode.

[0080] When the cooling circuit 101 is operated in the second mode, the battery temperature T bat is the upper limit T batUL The battery temperature T bat When the battery temperature T falls within the appropriate temperature range, the controller 102 ends the operation in the second mode and switches the operation mode of the cooling circuit 101 to the first mode. bat is temporarily selected until the temperature falls within the appropriate temperature range.

[0081] In step S12, the battery temperature T bat is the upper limit T batUL Battery temperature T bat If the temperature is already within the appropriate temperature range and there is no need to immediately cool the battery 12, step S13 is skipped. Then, the controller 102 drives the cooling circuit 101 in the first operation mode.

[0082] When it is determined in step S10 that the ignition is off (IGN=OFF) and the electric vehicle is in a state in which it can run, the process proceeds to step S14. In step S14, the controller 102 calculates the battery temperature T bat and the upper limit TbatUL By comparing these values, it is determined whether cooling of the battery 12 (mandatory cooling) is required.

[0083] In step S14, the battery temperature T bat is the upper limit T batUL or more, and the battery temperature T bat When it is determined that the battery 12 must be cooled in order to maintain the battery temperature T within an appropriate temperature range, the process proceeds to step S15. In step S15, the controller 102 selects the third mode as the operation mode of the cooling circuit 101, and drives the cooling circuit 101 in the third mode. For example, after high load driving, bat is the upper limit T batUL If the electric vehicle is stopped while the battery temperature is above T bat rises, and the upper limit T batUL If this is the case, the cooling circuit 101 is operated in the third mode.

[0084] When the cooling circuit 101 is driven in the third mode, the battery temperature T bat is the upper limit T batUL The battery temperature T bat When the battery temperature T bat When the time required for the battery temperature T to reach the appropriate temperature range is known through an experiment, a simulation, or the like, the controller 102 can drive the cooling circuit 101 in the third mode for a predetermined time and then stop driving the cooling circuit 101. In any case, the third mode is bat is temporarily selected until the temperature falls within the appropriate temperature range.

[0085] In step S14, the battery temperature T bat is the upper limit T batUL Battery temperature T batWhen the temperature of the cooling circuit 101 is already within the appropriate temperature range and there is no need to immediately cool the battery 12, the controller 102 skips step S15 and maintains the cooling circuit 101 in a stopped state.

[0086] FIG. 8 is a flowchart showing the selection and switching between the fourth mode and the fifth mode.

[0087] The controller 102 selects the fourth or fifth mode as necessary when the cooling circuit 101 is operated in the first mode or when the cooling circuit 101 is stopped. That is, when the cooling circuit 101 must be operated in the second or third mode, these operating modes are prioritized, and when operation in the second or third mode is not required, the fourth or fifth mode is selected. More simply, the fourth or fifth mode is selected when preventive cooling can be performed in a scene where mandatory cooling is not required.

[0088] Specifically, as shown in FIG. 8, in step S20, the controller 102 env , battery temperature T bat , and the current refrigerant liquid temperature T ref-C In step S21, the controller 102 acquires the outside air temperature T env and the current refrigerant liquid temperature T ref-C Based on this, the supply refrigerant liquid temperature T ref-est Calculate (estimate) the following.

[0089] In step S22, the controller 102 detects the outside air temperature T env is the battery temperature T bat In this embodiment, in more detail, the controller 102 determines whether the supply refrigerant liquid temperature T ref-est and battery temperature T bat Difference (T ref-est -T batWhether or not effective preventive cooling can be performed is determined by comparing the calculated temperature difference Δ with a reference value Δ. The reference value Δ is determined in advance by an experiment, a simulation, or the like.

[0090] In step S22, the supply refrigerant liquid temperature T ref-est and battery temperature T bat Difference (T ref-est -T bat ) is greater than the reference value Δ and it is determined that effective preventive cooling can be performed, the process proceeds to step S23.

[0091] In step S23, the controller 102 determines whether the battery 12 is excessively cooled. In this embodiment, the controller 102 determines a lower limit T batLL The threshold value (T batLL +δ) and battery temperature T bat By comparing the temperature margin δ with the temperature margin δ, it is determined whether or not the battery 12 is excessively cooled. The temperature margin δ is determined by an experiment, a simulation, or the like.

[0092] In step S23, the battery temperature T bat is the threshold (T batLL +δ) and it is determined that the battery 12 is not excessively cooled, the process proceeds to step S24. In step S24, the controller 102 determines whether the electric vehicle is in a runnable state based on the state of the ignition (IGN) of the electric vehicle.

[0093] If it is determined in step S24 that the ignition is on (ING=ON) and the electric vehicle is in a runnable state, the process proceeds to step S25. Then, in step S25, the controller 102 selects the fourth mode. That is, the controller 102 switches the operation mode of the cooling circuit 101 from the first mode and drives the cooling circuit 101 in the fourth mode.

[0094] On the other hand, if it is determined in step S24 that the ignition is off (IGN=OFF) and the electric vehicle is not capable of traveling, the process proceeds to step S26. Then, in step S26, the controller 102 selects the fifth mode. That is, the controller 102 drives the cooling circuit 101, which has been stopped, in the fifth mode.

[0095] When the cooling circuit 101 is driven in the fourth or fifth mode in this way, the process proceeds to step S27. In step S27, the controller 102 checks whether the grill shutter 23 is open or closed, and opens the grill shutter 23 when the grill shutter 23 is closed.

[0096] In step S28, the controller 102 adjusts the output of the pump 19 and the output of the blower fan 24 depending on the operating mode of the cooling circuit 101 (the fourth mode or the fifth mode), and adjusts the flow rate of the refrigerant liquid circulating through the battery 12 and the radiator 13, and the amount of air blown to the radiator 13.

[0097] Specifically, when the cooling circuit 101 is operated in the fifth mode, the controller 102 operates the pump 19 and / or the blower fan 24 at a relatively low output so that the flow rate of the refrigerant liquid and / or the amount of blown air are smaller than when the cooling circuit 101 is operated in the fourth mode. That is, when preventive cooling of the battery 12 is performed, when the electric vehicle is in a non-travelable state (fifth mode), the flow rate of the refrigerant liquid and the amount of blown air are made smaller than when the electric vehicle is in a travelable state (fourth mode). Note that in the fifth mode, the blower fan 24 may be stopped.

[0098] On the other hand, when the cooling circuit 101 is operated in the fourth mode, the controller 102 operates the pump 19 and / or the blower fan 24 at a relatively high output so that the flow rate of the refrigerant liquid and / or the amount of blown air are increased compared to when the cooling circuit 101 is operated in the fifth mode. That is, when preventive cooling of the battery 12 is performed, when the electric vehicle is in a runnable state (fourth mode), the flow rate of the refrigerant liquid and the amount of blown air are increased compared to when the electric vehicle is in a non-runnable state (fifth mode). In this embodiment, when the cooling circuit 101 is operated in the fourth mode, the controller 102 operates the pump 19 and the blower fan 24 at substantially maximum output.

[0099] In step S22, the battery temperature T bat is the outside temperature T env The supply refrigerant liquid temperature T ref-est and battery temperature T bat When it is determined that the difference between the battery temperature T bat is the threshold (T batLL +δ) or less and it is determined that the battery 12 has been sufficiently cooled, the process proceeds to step S29, and the controller 102 stops preventive cooling of the battery 12.

[0100] Figure 9 shows the outside temperature T env and battery temperature T bat 9 is a graph showing a schematic diagram of the circadian change of the outside air temperature T env is shown by a dashed line, and the battery temperature T bat The circadian change of bat1 9, for comparison, the battery temperature T bat The circadian change in bat2 For simplicity, in Fig. 9, the outside air temperature T env Battery temperature T bat This shows the change in

[0101] As shown in FIG. 9, the battery temperature T bat is the outside temperature T env Specifically, it varies depending on the outside temperature T env rises during the day and falls at night. Therefore, the battery temperature T bat Moko's outside temperature T env It rises during the day and falls at night, roughly following the changes in

[0102] At this time, in this embodiment, the outside air temperature T env is the battery temperature T bat For example, after midnight, the supply refrigerant liquid temperature T ref-est and battery temperature T bat Difference (T ref-est -T bat When the battery temperature T bat Since both temperatures are within the appropriate temperature range, the operation mode of the cooling circuit 101 is the fifth mode.

[0103] And the battery temperature T bat Solid line indicating (T bat1 ) and the battery temperature T without preventive cooling bat The dashed line (T bat2 ) and, as shown by, preventive cooling reduces the daytime battery temperature T bat Including battery temperature T bat Therefore, even when the electric vehicle is driven, the battery temperature T bat This makes it easier to keep the temperature of the battery 12 within an appropriate temperature range, thereby suppressing (preventing) deterioration of the battery 12.

[0104] Thus, the battery temperature T batWhen the temperature is within the appropriate temperature range, the refrigerant gas circulation circuit 113 (compressor) can be used for essential cooling when the battery 12 is preventively cooled to suppress deterioration.

[0105] However, the refrigerant gas circulation circuit 113 (compressor) consumes a large amount of power from the battery 12. Therefore, when the refrigerant gas circulation circuit 113 (compressor) is used for preventive cooling, the battery 12 deteriorates due to an increase in the integrated charge / discharge amount. In other words, when the refrigerant gas circulation circuit 113 (compressor) is used for preventive cooling, the battery temperature T bat From this viewpoint, it may seem that the deterioration of the battery 12 can be suppressed, but from the viewpoint of the integrated charge / discharge amount, the deterioration of the battery 12 is accelerated. As a result, when the refrigerant gas circulation circuit 113 (compressor) is used, the deterioration of the battery 12 cannot be substantially suppressed. Moreover, the increase in the integrated charge / discharge amount may cause the deterioration of the battery 12 to progress rather than to progress.

[0106] On the other hand, in this embodiment, preventive cooling of the battery 12 is performed by exchanging heat with the outside air using the pump 19 and the blower fan 24, without using the refrigerant gas circulation circuit 113 (compressor). Compared with the power consumption of the refrigerant gas circulation circuit 113 (compressor), the power consumption of the pump 19 and the blower fan 24 is very small. In other words, the preventive cooling of this embodiment can reduce the battery temperature T bat Therefore, in this embodiment, the battery temperature T bat Therefore, the temperature of the battery 12 can be kept low within an appropriate temperature range, and deterioration of the battery 12 can be suppressed (prevented).

[0107] In addition, for example, if a battery fan (not shown) is used to blow air directly onto the battery 12 to cool it, the battery temperature T bat However, in this case, the battery temperature T bat In other words, the decrease in the battery temperature Tbat Therefore, it is not possible to effectively suppress (prevent) deterioration of the battery 12.

[0108] In contrast, in the preventive cooling of the present embodiment, as described above, the battery temperature T bat Since the current can be reduced relatively significantly, the deterioration of the battery 12 can be effectively suppressed (prevented).

[0109] As in the above embodiment, the preventive cooling of this embodiment may be performed when the electric vehicle is not capable of traveling. In this way, when the electric vehicle is not capable of traveling, it is difficult for the user (driver, passenger, etc.) to predict that the cooling circuit 101 will be activated for preventive cooling of the battery 12. For this reason, if the cooling circuit 101 is activated unexpectedly for preventive cooling, the user of the electric vehicle may feel uncomfortable (surprised, etc.) with respect to the electric vehicle. In addition, when the electric vehicle is not traveling, the user may be away from the electric vehicle. In such a case, the user of the electric vehicle may feel uncomfortable with the electric vehicle due to the unexpected activation of the cooling circuit 101 for preventive cooling.

[0110] Therefore, when the electric vehicle is in a non-travelable state and refrigerant liquid is circulated through the battery 12 and the radiator 13 to perform preventive cooling, it is preferable to notify a user of the electric vehicle that the battery 12 is being cooled. In this case, the controller 102 can select an arbitrary notification method. For example, the controller 102 can notify a user of the electric vehicle that the battery 12 is being cooled by displaying an HMI (human machine interface). In addition, the controller 102 can notify a user of the electric vehicle that the battery 12 is being cooled via an application program running on the user's smartphone.

[0111] Furthermore, when the electric vehicle is in a non-travelable state, people in the vicinity of the electric vehicle also cannot foresee that the cooling circuit 101 will be activated for preventive cooling of the battery 12. For this reason, when the electric vehicle appears to be in a non-travelable state based on its appearance (such as the lit state of lamps, etc.), if the cooling circuit 101 suddenly activates for preventive cooling of the battery 12, people in the vicinity of the electric vehicle may feel uneasy (surprised, etc.) about the electric vehicle. In particular, when the user is away from the electric vehicle, people in the vicinity of the electric vehicle are likely to feel uneasy (surprised, etc.) about the electric vehicle.

[0112] Therefore, when the electric vehicle is in a non-travelable state and the refrigerant liquid is circulated through the battery 12 and the radiator 13 to perform preventive cooling, it is preferable to notify people around the electric vehicle that the battery 12 is undergoing a cooling operation. In this case, the controller 102 can select any notification method that can be perceived from outside the electric vehicle. For example, the controller 102 can notify people around the electric vehicle that the battery 12 is undergoing a cooling operation by creating a state that reminds people from outside the electric vehicle that the electric vehicle is in a powered state, such as by activating a part of the HMI or a room lamp. In addition, when the electric vehicle is equipped with a device that displays characters, symbols, or the like or issues sounds or voices toward the outside of the vehicle, the controller 102 can use the device to notify people around the electric vehicle that the battery 12 is undergoing a cooling operation.

[0113] As described above, the battery cooling method according to the above-mentioned embodiment and the modified examples is a method for cooling the battery 12 in an electric vehicle having the battery 12 and the battery cooling circuit (101) that circulates a refrigerant liquid through the battery 12 using the pump 19. In this battery cooling method, the outside air temperature T env The battery temperature T bat Get the battery temperature T bat For the battery temperature T batis within the appropriate temperature range, and the outside temperature T env is the battery temperature T bat When the temperature is lower than 100° C., the battery 12 is cooled by circulating a refrigerant liquid through the radiator 13 that exchanges heat with the outside air and the battery 12.

[0114] Thus, the battery temperature T bat Even if the temperature is within the appropriate temperature range, the outside temperature T env is the battery temperature T bat If the battery 12 is preemptively cooled when the battery temperature T bat Since the increase in the battery temperature T bat Therefore, according to the battery cooling method according to the above embodiment and the modified example, the temperature of the battery can be significantly reduced with a smaller power consumption than in the past, and deterioration of the battery 12 can be effectively suppressed (prevented) even in terms of the integrated charge / discharge amount.

[0115] In the battery cooling method according to the above embodiment and the modified example, when the ignition of the electric vehicle is turned off and the electric vehicle is in a non-traveling state, the outside air temperature T env is the battery temperature T bat When the temperature is lower than this, the refrigerant liquid is circulated through the radiator 13 to cool the battery 12 even if the electric vehicle is not capable of running.

[0116] In this way, if preventive cooling is performed when the electric vehicle is not capable of running, deterioration of the battery 12 is particularly likely to be suppressed (prevented).

[0117] In the battery cooling methods according to the above-described embodiments and modified examples, the output of pump 19 is adjusted to reduce the flow rate of refrigerant liquid when the electric vehicle is in a non-travelable state, compared to the flow rate of refrigerant liquid when the electric vehicle is in a travelable state.

[0118] In this way, when performing preventive cooling while the electric vehicle is in a drivable state, by reducing the flow rate of the refrigerant liquid circulating through the battery 12 and the radiator 13, the power consumption of the pump 19 can be kept particularly low while the battery temperature T bat Therefore, even from the viewpoint of the integrated charge / discharge amount, deterioration of the battery 12 is particularly likely to be suppressed (prevented).

[0119] In the battery cooling methods according to the above-described embodiments and modified examples, the electric vehicle has a blower fan that blows air to the radiator 13, and when the electric vehicle is in a non-travelable state, the blower fan 24 is operated when circulating refrigerant liquid through the radiator 13.

[0120] In this way, when the blower fan 24 is operated for preventive cooling while the electric vehicle is not capable of traveling, even when there is no wind generated by traveling, the efficiency of heat exchange between the radiator 13 and the refrigerant liquid can be increased with very little power consumption by the blower fan 24. As a result, even from the viewpoint of the integrated charge / discharge amount, deterioration of the battery 12 is particularly easily suppressed (prevented).

[0121] In the battery cooling methods according to the above-described embodiments and modified examples, the output of the blower fan 24 is adjusted to reduce the amount of air blown when the electric vehicle is in a non-travelable state compared to the amount of air blown when the electric vehicle is in a travelable state.

[0122] In this way, when the blower fan 24 is operated while the electric vehicle is in a non-travelable state, if the output of the blower fan 24 is set to a small value, the power consumption of the blower fan 24 can be suppressed while the battery temperature T bat Therefore, even from the viewpoint of the integrated charge / discharge amount, deterioration of the battery 12 is particularly likely to be suppressed (prevented). In addition, since preventive cooling may be performed at night (late at night) when the electric vehicle is not capable of running, there is an advantage in that the operating noise of the blower fan 24 can be reduced by suppressing the output of the blower fan 24 as described above.

[0123] In the battery cooling method according to the above embodiment and modified examples, the electric vehicle has a refrigerant gas circulation circuit 113 that generates a temperature difference between the chiller 14 and the condenser 22 by the latent heat of the refrigerant gas, and an upper limit value T batUL Set the battery temperature T bat is the upper limit T batUL When the battery temperature T bat is the upper limit T batUL If the outside temperature T env is the battery temperature T bat When the temperature is lower than 100° C., the battery 12 is cooled by circulating a refrigerant liquid through the battery 12 and the radiator 13.

[0124] In this way, even if the refrigerant gas circulation circuit 113 (compressor) is used for essential cooling, preventive cooling is performed by circulating refrigerant liquid through the battery 12 and the radiator 13 and exchanging heat with the outside air, so that the battery temperature T bat Therefore, according to the battery cooling method according to the above embodiment and the modified examples, deterioration of the battery 12 can be effectively suppressed (prevented) from the viewpoint of the integrated charge / discharge amount as well.

[0125] In the battery cooling method according to the above embodiment and modified example, the outside air temperature T env and the current refrigerant liquid temperature T ref-C Based on this, the supply refrigerant liquid temperature T ref-est Then, estimate the outside temperature T env is the battery temperature T bat The supply refrigerant liquid temperature T ref-est and battery temperature T bat Difference (T ref-est -T batWhen the difference (T ref-est -T bat When the difference between the refrigerant temperature and the refrigerant amount becomes equal to or smaller than the reference value Δ, the circulation of the refrigerant liquid in the radiator 13 and the battery 12 is stopped.

[0126] In this way, the supply refrigerant liquid temperature T ref-est If the start and stop of preventive cooling is determined based on the above, deterioration of the battery 12 can be effectively suppressed (prevented) in particular from the viewpoint of the integrated charge / discharge amount.

[0127] In the battery cooling method according to the above embodiment and modified example, the battery temperature T bat is a predetermined threshold (T batLL +δ) or less, the circulation of the refrigerant liquid in the radiator 13 and the battery 12 is stopped.

[0128] Thus, the battery temperature T bat is a predetermined threshold (T batLL If preventive cooling is stopped when the temperature drops below 100°C (+δ), excessive cooling due to preventive cooling can be prevented.

[0129] In the battery cooling method according to the above-described embodiments and modified examples, the electric vehicle has a grill shutter 23 that blocks ventilation to the radiator 13, and when circulating refrigerant liquid through the radiator 13 and the battery 12, the grill shutter 23 is opened.

[0130] In this way, when the electric vehicle has the grill shutter 23, opening the grill shutter 23 during preventive cooling can improve the efficiency of heat exchange between the outside air and the coolant in the radiator 13. This makes it particularly easy to suppress (prevent) deterioration of the battery 12 in terms of the accumulated charge / discharge amount.

[0131] In the battery cooling method according to the above-described embodiment and modification examples, when circulating the refrigerant liquid through the battery 12 and the radiator 13 while the electric vehicle is in a non-drivable state, the user of the electric vehicle is notified that the battery 12 is in the cooling operation.

[0132] Thus, when performing preventive cooling while the electric vehicle is in a non-drivable state, if the user of the electric vehicle is notified that the battery 12 is in the cooling operation, the user is less likely to feel uncomfortable with the electric vehicle.

[0133] In the battery cooling method according to the above-described embodiment and modification examples, when circulating the refrigerant liquid through the battery 12 and the radiator 13 while the electric vehicle is in a non-drivable state, the people around the electric vehicle are notified that the battery 12 is in the cooling operation.

[0134] Thus, when performing preventive cooling while the electric vehicle is in a non-drivable state, if the people around the electric vehicle are notified that the battery 12 is in the cooling operation, the people around the electric vehicle are less likely to feel uncomfortable with the electric vehicle.

[0135] The battery cooling circuit according to the above-described embodiment and modification examples is a battery cooling circuit (101) mounted on an electric vehicle having a refrigerant gas circulation circuit 113 that generates a temperature difference between the chiller 14 and the capacitor 22 by the latent heat of the refrigerant gas, and circulates the refrigerant liquid through the battery 12 using the pump 19. This battery cooling circuit (101) has a battery temperature T which is the temperature of the battery 12 bat When it becomes equal to or higher than a preset upper limit value T batUL the refrigerant liquid is circulated through the chiller 14 cooled by the refrigerant gas circulation circuit 113. On the other hand, when the battery temperature T bat is lower than the upper limit value T batUL and the outside air temperature T env which is the temperature of the outside air is lower than the battery temperature T bat the refrigerant liquid is circulated through the battery 12 and the radiator 13 that exchanges heat with the outside air.

[0136] In this way, even if the refrigerant gas circulation circuit 113 (compressor) is used for essential cooling, preventive cooling is performed by circulating refrigerant liquid through the battery 12 and the radiator 13 and exchanging heat with the outside air, so that the battery temperature T bat Therefore, according to the battery cooling method according to the above embodiment and the modified examples, deterioration of the battery 12 can be effectively suppressed (prevented) from the viewpoint of the integrated charge / discharge amount as well.

[0137] The battery cooling control device according to the above-mentioned embodiment and modified examples is a battery cooling control device (controller 102) that controls the cooling of the battery 12 in an electric vehicle having a battery 12 and a battery cooling circuit (101) that circulates a refrigerant liquid through the battery 12 using a pump 19. This battery cooling control device (controller 102) controls the cooling of the battery 12 based on an outside air temperature T env The battery temperature T bat Get the battery temperature T bat For the battery temperature T bat is within the appropriate temperature range, and the outside temperature T env is the battery temperature T bat When the temperature is lower than 100° C., the battery 12 is cooled by circulating a refrigerant liquid through the radiator 13 that exchanges heat with the outside air and the battery 12.

[0138] Thus, the battery temperature T bat Even if the temperature is within the appropriate temperature range, the outside temperature T env is the battery temperature T bat If the battery 12 is preemptively cooled when the battery temperature T bat Since the increase in the battery temperature T batTherefore, according to the battery cooling method according to the above embodiment and the modified example, the temperature of the battery can be significantly reduced with a smaller power consumption than in the past, and deterioration of the battery 12 can be effectively suppressed (prevented) even in terms of the integrated charge / discharge amount.

[0139] Although the embodiments of the present invention have been described above, the configurations described in the above embodiments and modified examples merely show some of the application examples of the present invention and are not intended to limit the technical scope of the present invention. [Explanation of symbols]

[0140] 11: electric power train, 12: battery, 13: radiator, 14: chiller, 15: heater, 16: valve, 17: valve, 18: pump, 19: pump, 21: expansion unit, 22: condenser, 23: grill shutter, 24: blower fan, 100: cooling system, 101: cooling circuit, 102: controller, 112: refrigerant liquid circulation circuit, 113: refrigerant gas circulation circuit

Claims

1. A battery cooling method for cooling a battery in an electric vehicle having a battery and a battery cooling circuit that circulates a refrigerant liquid through the battery using a pump, comprising: Obtain the outside air temperature, which is the temperature of the outside air, A battery temperature is acquired, the battery temperature being a temperature of the battery; setting an appropriate temperature range for the battery temperature in which deterioration of the battery is unlikely to occur; When the battery temperature is within the appropriate temperature range and the outside air temperature is lower than the battery temperature, the refrigerant liquid is circulated through the battery and a radiator that exchanges heat with the outside air, thereby cooling the battery. Battery cooling method.

2. 2. The battery cooling method according to claim 1, When an ignition of the electric vehicle is turned off and the electric vehicle is in a non-traveling state, when the outside air temperature becomes lower than the battery temperature, the refrigerant liquid is circulated through the radiator to cool the battery even when the electric vehicle is in a non-traveling state. Battery cooling method.

3. 3. The battery cooling method according to claim 2, further comprising: By adjusting an output of the pump, a flow rate of the refrigerant liquid when the electric vehicle is in a non-travelable state is reduced compared to a flow rate of the refrigerant liquid when the electric vehicle is in a travelable state. Battery cooling method.

4. 3. The battery cooling method according to claim 2, further comprising: the electric vehicle has a blower fan that blows air to the radiator, When the electric vehicle is in a non-travelable state, the blower fan is operated when the refrigerant liquid is circulated through the radiator. Battery cooling method.

5. 5. The battery cooling method according to claim 4, further comprising the steps of: By adjusting the output of the blower fan, the amount of air blown when the electric vehicle is in a non-travelable state is reduced compared to the amount of air blown when the electric vehicle is in a travelable state. Battery cooling method.

6. The battery cooling method according to any one of claims 1 to 5, The electric vehicle has a refrigerant gas circulation circuit that generates a temperature difference between a chiller and a condenser by latent heat of a refrigerant gas, setting an upper limit value for the battery temperature; When the battery temperature is equal to or higher than the upper limit value, the chiller is cooled by the refrigerant gas circulation circuit, and the refrigerant liquid is circulated through the battery and the chiller to cool the battery; When the battery temperature is lower than the upper limit value and the outside air temperature is lower than the battery temperature, the battery is cooled by circulating the refrigerant liquid through the battery and the radiator. Battery cooling method.

7. The battery cooling method according to any one of claims 1 to 5, estimating a supply refrigerant liquid temperature, which is the temperature of the refrigerant liquid supplied to the battery when the refrigerant liquid is circulated through the radiator, based on the outside air temperature and a current refrigerant liquid temperature, which is the current temperature of the refrigerant liquid; when the outside air temperature is lower than the battery temperature and a difference between the supply refrigerant liquid temperature and the battery temperature is greater than a predetermined reference value, starting circulation of the refrigerant liquid in the radiator and the battery; When the difference becomes equal to or smaller than the reference value, the circulation of the refrigerant liquid in the radiator and the battery is stopped. Battery cooling method.

8. 8. The battery cooling method according to claim 7, further comprising: When the battery temperature becomes equal to or lower than a predetermined threshold value, the circulation of the refrigerant liquid in the radiator and the battery is stopped. Battery cooling method.

9. 2. The battery cooling method according to claim 1, the electric vehicle has a grill shutter that blocks ventilation to the radiator, When the refrigerant liquid is circulated through the radiator and the battery, the grill shutter is opened. Battery cooling method.

10. 3. The battery cooling method according to claim 2, further comprising: When the electric vehicle is in a non-travelable state and the refrigerant liquid is circulated through the battery and the radiator, a user of the electric vehicle is notified that a cooling operation of the battery is being performed. Battery cooling method.

11. 3. The battery cooling method according to claim 2, further comprising: When the electric vehicle is in a non-travelable state and the refrigerant liquid is circulated through the battery and the radiator, a person in the vicinity of the electric vehicle is notified that a cooling operation of the battery is being performed. Battery cooling method.

12. A battery cooling circuit that is mounted on an electric vehicle having a refrigerant gas circulation circuit that generates a temperature difference between a chiller and a condenser by latent heat of a refrigerant gas, and circulates a refrigerant liquid to a battery using a pump, When a battery temperature, which is a temperature of the battery, becomes equal to or higher than a predetermined upper limit value, the refrigerant liquid is circulated through the chiller cooled by the refrigerant gas circulation circuit; When the battery temperature is lower than the upper limit value, and an outside air temperature is lower than the battery temperature, the refrigerant liquid is circulated through the battery and a radiator that exchanges heat with the outside air. Battery cooling circuit.

13. A battery cooling control device for an electric vehicle having a battery and a battery cooling circuit that circulates a refrigerant liquid through the battery using a pump, the battery cooling control device comprising: Obtain the outside air temperature, which is the temperature of the outside air, A battery temperature is acquired, the battery temperature being a temperature of the battery; setting an appropriate temperature range for the battery temperature in which deterioration of the battery is unlikely to occur; When the battery temperature is within the appropriate temperature range and the outside air temperature is lower than the battery temperature, the refrigerant liquid is circulated through the battery and a radiator that exchanges heat with the outside air, thereby cooling the battery. Battery cooling control device.

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