Cooling System of Electrical Energy Storage Device

Abstract

A cooling system for an electricity storage device, the cooling system of the electricity storage device includes a blower fan and a control device for controlling the blower fan. The blower fan is mounted on a vehicle together with the electricity storage device and blows the air in the vehicle interior towards the electricity storage device. The control device stops the blower fan when it confirms the establishment of a predetermined condition, and the predetermined condition is that the vehicle is in a parked state, and a current-related value related to the current of the electricity storage device is within a predetermined range including the value 0, and the blower fan is being driven, and the temperature of the electricity storage device continues to rise.

Description

Technical Field

[0001] The present invention relates to a cooling system for an electricity storage device. Background Art

[0002] Conventionally, as a cooling system for such an electricity storage device, a cooling system has been proposed which includes "a cooling fan that takes in air in the vehicle interior and blows it into the electricity storage device" and "an intake air temperature sensor provided in an intake air passage from an intake port of the air in the vehicle interior to the electricity storage device via the cooling fan" (for example, refer to Japanese Unexamined Patent Application Publication No. 2018-95061). In this cooling system, variable control is performed to change the rotational speed of the cooling fan according to the temperature of the electricity storage device within a range below the maximum allowable rotational speed of the cooling fan corresponding to the vehicle speed. Further, when the volume of the air sent out by the cooling fan becomes equal to or greater than the volume of the intake air passage from the intake port of the air to the intake air temperature sensor, the intake air temperature is obtained from the intake air temperature sensor, and when the intake air temperature is equal to or higher than the temperature of the electricity storage device, the cooling fan is stopped. In this way, an increase in the temperature of the electricity storage device due to the temperature in the vehicle interior being higher than the temperature of the electricity storage device is suppressed. Summary of the Invention

[0003] In the above-described cooling system, in order to determine whether the temperature in the vehicle interior is higher than the temperature of the electricity storage device, it is necessary to detect the intake air temperature by the intake air temperature sensor. On the other hand, in order to reduce the number of components of the system, etc., it is also required to omit the intake air temperature sensor, or not to use the intake air temperature detected by the intake air temperature sensor when the reliability of the intake air temperature sensor is low. Therefore, "being able to suppress an increase in the temperature of the electricity storage device due to the temperature in the vehicle interior being higher than the temperature of the electricity storage device without providing an intake air temperature sensor or without using the intake air temperature detected by the intake air temperature sensor" has become one of the problems.

[0004] The main object of the cooling system for an electricity storage device of the present invention is to be able to suppress an increase in the temperature of the electricity storage device due to the temperature in the vehicle interior being higher than the temperature of the electricity storage device in a state where no temperature sensor is provided in the intake air passage for blowing the air in the vehicle interior into the electricity storage device, or without using the detection value of the temperature sensor when the temperature sensor is provided.

[0005] The cooling system for an electricity storage device of the present invention adopts the following technical means in order to achieve the above main object.

[0006] The gist of the cooling system for an electricity storage device of the present invention is that,

[0007] the cooling system for the electricity storage device includes a blower fan and a control device that controls the blower fan, the blower fan being mounted on a vehicle together with the electricity storage device and blowing the air in the vehicle interior toward the electricity storage device,

[0008] When the control device confirms the establishment of a predetermined condition, it stops the air supply fan. The predetermined condition is that the vehicle is in a parked state, a current-related value related to the current of the power storage device is within a predetermined range including the value 0, the air supply fan is being driven, and the temperature of the power storage device continues to rise.

[0009] In the cooling system of the power storage device of the present invention, when the establishment of a predetermined condition is confirmed, the air supply fan is stopped. The predetermined condition is that the vehicle is in a parked state, a current-related value related to the current of the power storage device is within a predetermined range including the value 0, the air supply fan is being driven, and the temperature of the power storage device continues to rise. When the vehicle is in a parked state, the current-related value is within a predetermined range (assuming that the heat generation of the power storage device is small enough), and the air supply fan is being driven, if the temperature of the power storage device continues to rise, it is assumed that the temperature in the vehicle interior is higher than the temperature of the power storage device. Therefore, by stopping the air supply fan when the establishment of the predetermined condition is confirmed, it is possible to suppress a further temperature rise of the power storage device caused by the temperature in the vehicle interior being higher than the temperature of the power storage device. Here, the "current-related value" includes not only current but also the square value of the current, a processed value obtained by performing a slow change process on the current and the square value of the current, the heat generation amount of the power storage device obtained by multiplying the square value of the current by the internal resistance value of the power storage device, and the like.

[0010] In the cooling system of the power storage device of the present invention, it may be that the control device determines that the establishment of the predetermined condition is confirmed when the duration of the establishment of the predetermined condition reaches a predetermined time or more. Additionally, it may be that the control device counts a counter as the predetermined condition continues to hold, and resets the counter when the predetermined condition does not hold, and determines that the establishment of the predetermined condition is confirmed when the counter reaches a predetermined value or more. Thereby, it is possible to more appropriately confirm the establishment of the predetermined condition.

[0011] In the cooling system of the power storage device of the present invention, it may be that the control device, after stopping the air supply fan upon confirming the establishment of the predetermined condition, drives the air supply fan when the temperature of the power storage device reaches a first predetermined temperature or more, and continues to drive the air supply fan until the temperature of the power storage device becomes lower than a second predetermined temperature lower than the first predetermined temperature. When the temperature of the power storage device reaches a first predetermined temperature or more after the air supply fan is stopped upon confirming the establishment of the predetermined condition, it is assumed that the temperature rise of the power storage device is not caused by "blowing the air in the vehicle interior, the temperature of which is higher than the temperature of the power storage device, onto the power storage device by the air supply fan", but by other factors. Therefore, by driving the air supply fan, it is possible to suppress overheating of the power storage device. Description of the Drawings

[0012] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals denote like elements, and in which:

[0013] Figure 1 is a configuration diagram showing a general configuration of an electric vehicle 20 equipped with a cooling system for a power storage device as an embodiment of the present invention.

[0014] Figure 2 is a flowchart showing an example of a control routine executed by the ECU 70.

[0015] Figure 3 is an explanatory diagram showing an example of the temperature Tb of the main battery 38 and the driving state of the air supply fan 60 when the parking state condition and the low heat generation condition are satisfied.

[0016] Figure 4 is a flowchart showing an example of a control routine executed by the ECU 70.

[0017] Figure 5 is an explanatory diagram showing an example of the temperature Tb of the main battery 38 and the driving state of the air supply fan 60 when the parking state condition and the low heat generation condition are satisfied. Detailed Embodiments

[0018] Next, embodiments of the present invention will be described using examples.

[0019] Figure 1 is a configuration diagram showing a general configuration of an electric vehicle 20 equipped with a cooling system for a power storage device as an embodiment of the present invention. The electric vehicle 20 of the embodiment includes a driving motor 32, a driving inverter 34, a main battery 38 as a power storage device, an auxiliary battery 40, a DC / DC converter 44, a cooling device 50, and an electronic control unit (hereinafter referred to as "ECU") 70. In addition, the electric vehicle 20 can charge the main battery 38 using power from an external power source during system shutdown. The cooling system for the power storage device as an embodiment mainly includes the cooling device 50 and the ECU 70.

[0020] The traveling motor 32 is configured as a synchronous generator motor, for example. The rotor of the traveling motor 32 is connected to the drive shaft 26, and the drive shaft 26 is connected to the drive wheels 22 via the differential gear 24. The traveling converter 34 is used to drive the traveling motor 32 and is connected to the power line 36. When a voltage is applied to the traveling converter 34, the ECU 70 performs switching control on a plurality of switching elements of the traveling converter 34, and the traveling motor 32 is driven to rotate. An air conditioning device (compressor) (not shown) that performs air conditioning in the vehicle interior is also connected to the power line 36.

[0021] The main battery 38 is configured as a lithium-ion secondary battery or a nickel-metal hydride secondary battery with a rated voltage of about several hundred V, for example, and is connected to the power line 36. The main battery 38 is housed in the housing 52. The auxiliary battery 40 is configured as a lithium-ion secondary battery, a nickel-metal hydride secondary battery, or a lead-acid battery with a rated voltage of 12V, for example, and is connected to the power line 42. In addition to the auxiliary battery 40, a fan converter 64 of the cooling device 50, the ECU 70, lights (not shown), an audio system, a navigation device, etc. are also connected to the power line 42. The DC / DC converter 44 is connected to the power line 36 and the power line 42, steps down the power of the power line 36, and supplies it to the power line 42.

[0022] The cooling device 50 includes the above-described housing 52, an intake passage 54, a blower fan 60, a fan motor 62, and a fan converter 64. The main battery 38 and the cooling device 50 are arranged in the vehicle interior, for example, under the rear seat. An intake port 52i and an exhaust port 52o are formed in the housing 52. The air blown by the blower fan 60 circulates in the housing 52 through the intake port 52i and exchanges heat with the main battery 38. In addition, the air in the housing 52 is discharged from the exhaust port 52o.

[0023] The intake passage 54 is a passage for taking in the air in the vehicle interior from the intake opening 55 and guiding it to the intake port 52i of the housing 52 via the blower fan 60. In addition to the intake opening 55, it also has an intake channel 56, a housing portion 57 that houses the blower fan 60, and a connection channel 58. A filter 55f for removing dust is installed at the intake opening 55. The intake channel 56 is a passage for guiding the air from the intake opening 55 to the intake port 57i formed in the housing portion 57. In the housing portion 57, in addition to the intake port 57i for sucking the air from the intake channel 56, an air outlet 57o for sending out the air in the housing portion 57 to the connection channel 58 is also formed. The connection channel 58 is a passage for guiding the air from the housing portion 57 to the intake port 52i of the housing 52.

[0024] The air supply fan 60 is configured as, for example, a multi-blade fan (multi-wing air blower). The air supply fan 60 sends the air taken into the housing portion 57 through the intake port 57i from the intake passage 56 to the connection passage 58 through the air outlet 57o. The fan motor 62 is a motor for driving the air supply fan 60 to rotate, and is configured as, for example, a synchronous motor. The fan inverter 64 is used to drive the fan motor 62 and is connected to the power line 42. When a voltage is applied to the fan inverter 64, the ECU 70 performs switching control on a plurality of switching elements of the fan inverter 64, whereby the fan motor 62 (air supply fan 60) is driven to rotate.

[0025] Although not shown, the ECU 70 includes a microcomputer having a CPU, a ROM, a RAM, a flash memory, an input / output port, and a communication port. Signals from various sensors are input to the ECU 70 through the input port. As the signals input to the ECU 70, for example, the rotational position θmr of the rotor of the traveling motor 32 from a rotational position sensor (e.g., resolver 32a) can be cited. The temperature Tb of the main battery 38 from the temperature sensor 38t, the voltage Vb of the main battery 38 from the voltage sensor 38v, and the current Ib of the main battery 38 from the current sensor 38i can also be cited. The rotational position θmf of the fan motor 62 (air supply fan 60) from a rotational position sensor (e.g., resolver) 62a can also be cited. The start signal from the start switch 72, the shift position SP from a shift position sensor (not shown) that detects the operation position of a shift lever (not shown), the accelerator opening Acc from an accelerator pedal position sensor (not shown) that detects the depression amount of an accelerator pedal (not shown), the brake pedal position (not shown) from a brake pedal position sensor that detects the depression amount of a brake pedal (not shown), and the vehicle speed V from the vehicle speed sensor 74 can also be cited.

[0026] Various control signals are output from the ECU 70 via the output ports. As signals output from the ECU 70, for example, there can be cited a control signal for the traveling converter 34, a control signal for the DC / DC converter 44, and a control signal for the fan converter 64. The ECU 70 calculates the rotational speed Nmr of the traveling motor 32 based on the rotational position θmr of the rotor of the traveling motor 32 from the rotational position sensor 32a, and calculates the rotational speed Nmf (rotational speed Nf of the blower fan 60) of the fan motor 62 based on the rotational position θmf of the rotor of the fan motor 62 from the rotational position sensor 62a. In addition, the ECU 70 calculates the state of charge SOC of the main battery 38 based on the cumulative value of the current Ib of the main battery 38 from the current sensor 38i, and sets the allowable input / output power Win, Wout of the main battery 38 based on the temperature Tb of the main battery 38 and the state of charge SOC from the temperature sensor 38t (the side of discharging from the main battery 38 is positive). The allowable input power Win of the main battery 38 is set such that in the range of 0 or less, the higher the state of charge SOC, the smaller the absolute value, and the absolute value becomes smaller in the region where the temperature Tb is higher than the threshold Tbhi compared to the region where the temperature Tb is below the threshold Tbhi. The allowable output power Wout of the main battery 38 is set such that in the range of 0 or more, the lower the state of charge SOC, the smaller the absolute value, and the absolute value becomes smaller in the region where the temperature Tb is higher than the threshold Tbhi compared to the region where the temperature Tb is below the threshold Tbhi.

[0027] In the electric vehicle 20 of the embodiment configured as described above, the ECU 70 sets the required torque Td* (required for the drive shaft 26) for traveling based on the accelerator opening Acc and the vehicle speed V, and sets a temporary value, i.e., a temporary torque Tmtmp, of the torque command Tm* of the traveling motor 32 so as to output the set required torque Td* to the drive shaft 26. In addition, the allowable input / output power Win, Wout of the main battery 38 is divided by the rotational speed Nmr of the traveling motor 32 to set the allowable upper and lower limit torques Tmin, Tmax of the traveling motor 32. Then, the temporary torque Tmtmp of the traveling motor 32 is limited by the allowable upper and lower limit torques Tmin, Tmax to set the torque command Tm* of the traveling motor 32, and the plurality of switching elements of the traveling converter 34 are switched and controlled so that the traveling motor 32 is driven according to the torque command Tm*.

[0028] Next, the operation of the cooling system of the power storage device provided in the electric vehicle 20 of the embodiment, particularly, the control of the blower fan 60 will be described. Figure 2 It is a flowchart showing an example of a control routine executed by the ECU 70. This routine is repeatedly executed.

[0029] When executedFigure 2 When the control routine is executed, the ECU 70 first inputs data such as the temperature Tb, current Ib, and vehicle speed V of the main battery 38 (step S100). Here, regarding the temperature Tb of the main battery 38, the value detected by the temperature sensor 38t is input. Regarding the current Ib of the main battery 38, the value detected by the current sensor 38i is input. Regarding the vehicle speed V, the value detected by the vehicle speed sensor 74 is input.

[0030] After the data is input in this way, it is determined whether the parking state condition indicating that the vehicle is in a parked state is satisfied based on the vehicle speed V (step S110), whether the small heat generation condition indicating that the heat generation of the main battery 38 is small enough not to affect its temperature rise is satisfied based on the current Ib of the main battery 38 (step S120), and whether the drive temperature condition requiring the drive of the blower fan 60 to cool the main battery 38 is satisfied based on the temperature Tb of the main battery 38 (step S130).

[0031] Here, the process of step S110 is performed by determining whether the vehicle speed V is equal to or lower than the threshold value Vref. As the threshold value Vref, for example, 0 km / h or a value slightly higher than that is used. The process of step S120 is performed by determining whether the square value of the current Ib of the main battery 38 is equal to or lower than the threshold value Ibref, and for example, a square value of about several A is used. The threshold value Ibref is set based on the specifications of the main battery 38, especially its heat capacity, etc. The process of step S130 is performed by determining whether the temperature Tb of the main battery 38 is equal to or higher than the threshold value Tbref1. The threshold value Tbref1 is set based on the specifications of the main battery 38, and for example, about 30°C to 40°C is used.

[0032] When it is determined in step S110 that the parking state condition is not satisfied, when it is determined in step S120 that the small heat generation condition is not satisfied, and when it is determined in step S130 that the drive temperature condition is not satisfied, the normal control of the blower fan 60 is executed (step S140), the counter Csp is reset to the value 0 (step S150), and this routine ends. Here, the counter Csp represents the duration when the parking state condition, the small heat generation condition, and the drive temperature condition are satisfied, the blower fan 60 is being driven, and the temperature of the main battery 38 continues to rise.

[0033] Here, the fan normal control is performed as follows. During the stop period of the air supply fan 60 (fan motor 62), when the temperature Tb of the main battery 38 reaches a threshold Tbref1 or higher, the ECU 70 starts driving the air supply fan 60. During the driving period of the air supply fan 60, when the temperature Tb of the main battery 38 reaches a threshold Tbref2 or lower that is lower than the threshold Tbref1, the ECU 70 stops driving the air supply fan 60. The threshold Tbref1 is a threshold for determining whether the above driving temperature condition is satisfied during the stop period of the air supply fan 60. The threshold Tbref2 is a threshold for determining whether the stop temperature condition for requiring the stop of the driving of the air supply fan 60 is satisfied during the driving period of the air supply fan 60. As the threshold Tbref2, for example, a value that is several °C lower than the threshold Tbref1 is used.

[0034] When driving the air supply fan 60, the following fan drive control is executed. The ECU 70 sets the target rotational speed Nf* of the air supply fan 60 (fan motor 62) based on the temperature Tb of the main battery 38 and the vehicle speed V, and performs switching control of a plurality of switching elements of the fan converter 64 so that the air supply fan 60 rotates at the target rotational speed Nf*. The target rotational speed Nf* can be set, for example, by protecting the temporary rotational speed Nftmp based on the temperature Tb of the main battery 38 with the allowable upper limit rotational speed Nfmax based on the vehicle speed V. The temporary rotational speed Nftmp is set such that the higher the temperature Tb of the main battery 38, the higher the temporary rotational speed Nftmp. This is to cool the main battery 38 according to the temperature Tb of the main battery 38. The allowable upper limit rotational speed Nfmax is set such that the higher the vehicle speed V, the higher the allowable upper limit rotational speed Nfmax. This is because the higher the vehicle speed V, the more the noise caused by the driving of the air supply fan 60 and the fan motor 62 will be mixed into the road noise, etc.

[0035] When it is determined in step S110 that the parking state condition is satisfied, and in step S120 that the low heat generation condition is satisfied, and in step S130 that the driving temperature condition is satisfied, it is determined whether the air supply fan 60 is in a forced stop state (step S160). The forced stop of the air supply fan 60 is performed by the process of step S210 described below. When it is determined that the air supply fan 60 is not in the forced stop state, the driving of the air supply fan 60 is started or continued (step S170). When driving the air supply fan 60, the above-described fan drive control is executed.

[0036] Next, it is determined whether the temperature of the main battery 38 continues to rise (step S180). This process can be performed, for example, by determining whether the current value of the temperature Tb of the main battery 38 is higher than the previous value. When the parking state condition, the low heat generation condition, and the driving temperature condition are satisfied and the air blowing fan 60 is being driven, the main battery 38 can be substantially cooled by blowing the air in the vehicle interior into the housing 52 by the air blowing fan 60. However, in the case of heating the vehicle interior using an air conditioning device (not shown) that can operate using the power from the power line 36 (main battery 38), etc., when the temperature in the vehicle interior is higher than the temperature Tb of the main battery 38 and the air with a temperature higher than the temperature Tb of the main battery 38 is blown into the housing 52 by the air blowing fan 60, the temperature Tb of the main battery 38 will rise. The process of step S180 is performed in consideration of this situation.

[0037] When it is determined in step S180 that the temperature of the main battery 38 does not continue to rise, the counter Csp is reset to the value 0 (step S150), and this routine ends. In this case, it is assumed that the main battery 38 is cooled by blowing the air in the vehicle interior into the housing 52 by the air blowing fan 60. And thereafter, when at least one of the parking state condition, the low heat generation condition, and the driving temperature condition is not satisfied, the normal control of the air blowing fan 60 is executed.

[0038] When it is determined in step S180 that the temperature of the main battery 38 continues to rise, the value of the counter Csp is incremented by 1 (step S190), and it is determined whether this counter Csp has reached a threshold value Cspref or more (step S200). As described above, when the parking state condition, the low heat generation condition, and the driving temperature condition are satisfied and the air blowing fan 60 is being driven, when the air with a temperature higher than the temperature Tb of the main battery 38 is blown into the housing 52 by the air blowing fan 60, the temperature Tb of the main battery 38 will rise. The threshold value Cspref is a count value corresponding to the time required to confirm the situation where "the parking state condition, the low heat generation condition, and the driving temperature condition are satisfied, and the air blowing fan 60 is being driven, and the temperature of the main battery 38 continues to rise", and the time required to determine the situation where "the temperature of the main battery 38 has risen due to blowing the air with a temperature higher than the temperature Tb of the main battery 38 into the housing 52 by the air blowing fan 60". As this threshold value Cspref, for example, a count value corresponding to about several minutes to several tens of minutes is used. In addition, as a situation where the parking state condition, the low heat generation condition, and the driving temperature condition are satisfied, and the air blowing fan 60 is being driven, and the temperature of the main battery 38 continues to rise, for example, the situation where an operator is inspecting the vehicle while heating the vehicle interior using an air conditioning device (not shown) at a dealership or a repair factory can be cited. When it is determined in step S200 that the counter Csp is less than the threshold value Cspref, this routine ends.

[0039] When it is determined in step S200 that the counter Csp is equal to or higher than the threshold value Cspref, it is determined that the situation of "the parking state condition, the low heat generation condition, the driving temperature condition are satisfied, the air supply fan 60 is being driven, and the temperature of the main battery 38 continues to rise" is confirmed, and it is determined that the situation of "the temperature of the main battery 38 rises by blowing air having a temperature higher than the temperature Tb of the main battery 38 into the housing 52 by the air supply fan 60" has occurred. Then, the air supply fan 60 is forcibly stopped (step S210), and this routine ends. Thereby, it is possible to suppress a further temperature rise of the main battery 38 caused by the temperature in the vehicle interior being higher than the temperature Tb of the main battery 38 without providing a temperature sensor in the intake passage 54 or without using the detected value thereof even if a temperature sensor is provided. And thereafter, when all of the parking state condition, the low heat generation condition, and the driving temperature condition are satisfied, it is determined in step S160 that the air supply fan 60 is in the forcibly stopped state, and this routine ends.

[0040] Figure 3 FIG. is an explanatory diagram showing an example of the temperature Tb of the main battery 38 and the presence or absence of driving of the air supply fan 60 when the parking state condition and the low heat generation condition are satisfied. As shown in the figure, during the stop period of the air supply fan 60 (in the stopped state), when the temperature Tb of the main battery 38 reaches a value equal to or higher than the threshold value Tbref1 and the driving temperature condition is satisfied (time t11), the driving of the air supply fan 60 is started. Then, during the driving period of the air supply fan 60, the counter Csp is incremented as the temperature of the main battery 38 rises, and when the counter Csp reaches a value equal to or higher than the threshold value Cspref (time t12), the air supply fan 60 is forcibly stopped. Thereby, it is possible to suppress a further temperature rise of the main battery 38 caused by the temperature in the vehicle interior being higher than the temperature Tb of the main battery 38 without providing a temperature sensor in the intake passage 54 or without using the detected value thereof even if a temperature sensor is provided.

[0041] In the cooling system of the power storage device included in the electric vehicle 20 according to the embodiment described above, when it is confirmed that the parking state condition, the low heat generation condition, the driving temperature condition are satisfied, the air supply fan 60 is being driven, and the temperature of the main battery 38 continues to rise, the air supply fan 60 is forcibly stopped. Thereby, it is possible to suppress a further temperature rise of the main battery 38 caused by the temperature in the vehicle interior being higher than the temperature Tb of the main battery 38 without providing a temperature sensor in the intake passage 54 or without using the detected value thereof even if a temperature sensor is provided.

[0042] In the cooling system of the power storage device of the embodiment, the ECU 70 determines whether the parking state condition is satisfied by determining whether the vehicle speed V is less than or equal to the threshold value Vref. However, it is also possible to determine whether the parking state condition is satisfied by determining whether the absolute value of the rotation speed Nmr of the travel motor 32 is less than or equal to the threshold value Nmrref, whether the rotation speed Nd of the drive shaft 26 is less than or equal to the threshold value Ndref, or whether the rotation speed Nw of the drive wheel 22 is less than or equal to the threshold value Nwref.

[0043] In the cooling system of the power storage device of the embodiment, the ECU 70 determines whether the heat generation condition is satisfied by determining whether the square value of the current Ib of the main battery 38 is below the threshold value Ibref. However, the heat generation condition may be satisfied by determining whether a processed value Ibsc obtained by applying a slow change process such as passivation processing (weighted average, etc.) or delay processing to the square value of the current Ib of the main battery 38 is below the threshold value Ibref2, whether the absolute value of the current Ib of the main battery 38 is below the threshold value Ibref3, or whether the absolute value of the processed value Ibsc2 obtained by applying a slow change process to the current Ib of the main battery 38 is below the threshold value Ibref4. In addition, the establishment of the low heat generation condition can be determined by determining whether the heat generation Qb of the main battery 38 obtained by multiplying the square value of the current Ib of the main battery 38 by the internal resistance value of the main battery 38 is below the threshold value Qbref1, or whether the processed value Qbsc after the heat generation Qb of the main battery 38 is subjected to a slow change process is below the threshold value Qbref2.

[0044] In the cooling system for the power storage device of the embodiment, the ECU 70 executes Figure 2 However, it is also possible to execute the control routine instead of Figure 4 control routine. Figure 4 The control routine of is the same as that of Figure 2 The control routines are the same. Figure 4 The control routine of Figure 2 The same processing in the control routine is marked with the same step number, and the detailed description is omitted.

[0045] exist Figure 4In the control routine, when the ECU 70 determines in step S180 that the air supply fan 60 is in the forced stop state, it determines whether the temperature Tb of the main battery 38 is equal to or higher than a threshold Tbref3 that is higher than the above-mentioned threshold Tbref1 (step S300). Here, the threshold Tbref3 is set to a temperature slightly lower than the overheat temperature of the main battery 38. For example, a temperature that is several tens of °C higher than the threshold Tbref1 and near the above-mentioned threshold Tbhi is used. When the temperature Tb of the main battery 38 further rises and reaches equal to or higher than the threshold Tbref3 while the air supply fan 60 is forced to stop, it is assumed that the temperature rise of the main battery 38 does not occur by blowing air with a temperature higher than the temperature Tb of the main battery 38 into the housing 52 by the air supply fan 60, but due to other factors. As other factors, for example, malfunction of an unillustrated heater that can use the power from the power line 42 (auxiliary battery 40) to heat the main battery 38 can be cited. The process of step 300 is to determine whether the temperature rise of the main battery 38 occurs due to such other factors. When it is determined in step S300 that the temperature Tb of the main battery 38 is lower than the threshold Tbref3, this routine ends.

[0046] When it is determined in step S300 that the temperature Tb of the main battery 38 is equal to or higher than the threshold Tbref3, it is determined that the temperature rise of the main battery 38 occurs due to the above-mentioned other factors, and the forced drive of the air supply fan 60 is started (step S310). When the forced drive of the air supply fan 60 is performed, the above-mentioned fan drive control is executed. Thereby, overheat of the main battery 38 can be suppressed. In addition, it is possible to suppress a malfunction caused by the temperature Tb of the main battery 38 being higher than the threshold Tbhi. For example, a malfunction such that the absolute values of the allowable input / output power Win and Wout of the main battery 38 become smaller and the performance of the main battery 38 cannot be fully exhibited. Next, the temperature Tb of the main battery 38 is input (step S320), and it is determined whether the input temperature Tb of the main battery 38 has reached equal to or lower than the above-mentioned threshold Tbref2 (step S330). When it is determined that the temperature Tb of the main battery 38 is higher than the threshold Tbref2, the process returns to step S320. By repeatedly executing the processes of steps S320 and S330 like this, when it is determined in step S340 that the main battery 38 has reached equal to or lower than the threshold Tbref2, the air supply fan 60 is stopped (step S340), and this routine ends.

[0047] Figure 5It is an explanatory diagram showing an example of the temperature Tb of the main battery 38 and the driving state of the air supply fan 60 when the parking state condition and the low heat generation condition are satisfied. As shown in the figure, during the stop period of the air supply fan 60, when the temperature Tb of the main battery 38 reaches or exceeds the threshold Tbref1 and the driving temperature condition is satisfied (time t21), the driving of the air supply fan 60 is started. Then, during the driving period of the air supply fan 60, the counter Csp is incremented as the temperature of the main battery 38 rises. When the counter Csp reaches or exceeds the threshold Cspref (time t22), the air supply fan 60 is forced to stop. When the temperature Tb of the main battery 38 further rises and reaches or exceeds the threshold Tbref3 even after the air supply fan 60 is forced to stop (time t23), it is determined that the temperature rise of the main battery 38 has occurred due to the above-mentioned other factors, and the forced driving of the air supply fan 60 is started. Thus, overheating of the main battery 38 can be suppressed. During the forced driving period of the air supply fan 60, when the temperature Tb of the main battery 38 reaches or falls below the threshold Tbref2 (time t24), the air supply fan 60 is stopped.

[0048] In the embodiment, it is assumed that the electric vehicle 20 includes a driving motor 32 and a main battery 38. However, it may also be configured as a hybrid vehicle that includes an engine in addition to the driving motor and the main battery 38. Alternatively, it may be configured as a fuel cell vehicle that includes a fuel cell in addition to the driving motor and the main battery 38.

[0049] The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of the technical solution for solving the problem will be described. In the embodiment, the air supply fan 60 corresponds to the "air supply fan", and the ECU 70 corresponds to the "control device".

[0050] In addition, in the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of the technical solution for solving the problem, the embodiment is an example for specifically explaining the implementation mode of the invention described in the column of the technical solution for solving the problem, and thus does not limit the elements of the invention described in the column of the technical solution for solving the problem. That is, the interpretation of the invention described in the column of the technical solution for solving the problem should be based on the description in that column, and the embodiment is merely a specific example of the invention described in the column of the technical solution for solving the problem.

[0051] As described above, the embodiments of the present invention have been described, but the present invention is not limited to such embodiments. Of course, it can be implemented in various ways without departing from the gist of the present invention.

[0052] The present invention can be applied to the manufacturing industry of the cooling system of the power storage device, etc.

Claims

1. A cooling system for an electricity storage device, The cooling system of the electricity storage device includes a blower fan and a control device for controlling the blower fan. The blower fan is mounted on a vehicle together with the electricity storage device and blows air in the vehicle interior toward the electricity storage device. When the control device confirms the establishment of a predetermined condition, the control device stops the blower fan, so as to suppress the temperature rise of the electricity storage device caused by the temperature in the vehicle interior being higher than the temperature of the electricity storage device, in a case where a temperature sensor is not provided in an intake passage for introducing air in the vehicle interior into the electricity storage device or the detected value of the temperature sensor is not used when the temperature sensor is provided. The predetermined condition is a condition that the vehicle is in a stopped state, a current-related value related to the current of the electricity storage device is within a predetermined range including the value 0, the blower fan is being driven, and the temperature of the electricity storage device continues to rise.

2. The cooling system for an electricity storage device according to claim 1, When the duration for which the predetermined condition is established reaches a predetermined time or more, the control device determines that the establishment of the predetermined condition has been confirmed.

3. The cooling system for an electricity storage device according to claim 1, The control device counts a counter as the predetermined condition continues to be established, resets the counter when the predetermined condition is not established, and determines that the establishment of the predetermined condition has been confirmed when the counter reaches a predetermined value or more.

4. The cooling system for an electricity storage device according to any one of claims 1 to 3, After the control device stops the blower fan upon confirming the establishment of the predetermined condition, when the temperature of the electricity storage device reaches a first predetermined temperature or more, the control device drives the blower fan and continues to drive the blower fan until the temperature of the electricity storage device becomes lower than a second predetermined temperature lower than the first predetermined temperature.

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