JP2006213210A - On-vehicle battery cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle battery cooling device having a battery mounted on a vehicle and a cooling fan to cool the battery to control the operational mode of the cooling fan which is capable of reducing the fan noise level sensible by an occupant, controlling the cooling fan to meet the cooling request in future, effectively cooling the battery, and reducing the power consumption of the cooling fan. <P>SOLUTION: The degree of the preceding cooling request of a battery 3 is operated based on at least the charging/discharging current of the battery 3 and the temperature of air sucked by a cooling fan 4. If the degree of the preceding cooling request is below a predetermined value, the target noise level of the cooling fan 4 is operated in a range of the background noise level based on the background noise level in a cabin and the degree of the preceding cooling request, and the rotational speed of the cooling fan 4 is controlled so as to reach the target noise level. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an in-vehicle battery cooling device for controlling an operation mode of a cooling fan for cooling a battery mounted on a vehicle.

  In hybrid vehicles and electric vehicles, the driving force of the vehicle can be obtained by driving the electric motor, and the electric energy stored in the rechargeable battery is used to drive the electric motor. I am doing so. Since such a battery has internal resistance, the temperature of the battery rises when charging and discharging are repeated. In general, if a battery continues to be used in a high temperature state, its life is shortened. Therefore, it is necessary to cool the battery so as to have an appropriate temperature.

For this reason, conventionally, for example, an apparatus as shown in Patent Document 1 or 2 below has been considered.
Among them, the device disclosed in Patent Document 1 relates to fan control for cooling a battery mounted on a vehicle. In order to cool an in-vehicle battery while reducing sensory noise due to fan operation noise, the temperature of the battery is set. The rotational speed of the fan is controlled based on the temperature level detected from the temperature sensor to be detected and the background noise prediction level obtained from the vehicle speed, the rotational speed of the internal combustion engine, and the like.

  In addition, in the apparatus disclosed in Patent Document 2, the cooling fan is controlled based on the battery temperature and the rate of change over time in order to reduce the power consumption by the cooling fan. The cooling fan is controlled to be turned on and off and the operating voltage of the cooling fan is switched so that the required blowing state is an adjusted blowing state adjusted according to the rate of change in battery temperature over time.

JP 2004-48981 A JP-A-10-64598

  However, in the configuration disclosed in Patent Document 1, since the rotation speed of the cooling fan is determined based on the battery temperature and the background noise of the passenger compartment, the cooling request of the battery is not necessarily reflected. In other words, since the battery generates heat after being energized and there is a time delay until the temperature of the battery rises, if the rotation speed of the cooling fan is controlled based on the actual battery temperature, a future cooling request is anticipated. The optimum fan operation cannot be performed, and effective battery cooling cannot be performed. In addition, since fan operation that anticipates future cooling requests is not performed, it is difficult to reduce power consumption of the cooling fan.

  Further, in the configuration disclosed in Patent Document 2, the rotation speed of the cooling fan is controlled regardless of the background noise in the passenger compartment, so that the operating noise of the cooling fan is relative to the background noise in the passenger compartment. The size of the vehicle increases, which is harsh to the passengers and uncomfortable.

  The present invention has been made in view of the above-described circumstances, and can reduce the fan noise level that can be perceived by an occupant. Further, the present invention can effectively control a cooling fan in response to a future cooling request. The main object is to provide an in-vehicle battery cooling device that can cool the battery and reduce the power consumption of the cooling fan.

  In order to achieve the above object, an in-vehicle battery cooling device according to the present invention includes a battery mounted on a vehicle and a cooling fan that cools the battery, and controls an operation mode of the cooling fan. In the configuration, at least a permissible noise level calculation means for calculating a background noise level in a vehicle interior excluding noise generated by rotation of the cooling fan, a charge / discharge current of the battery, and a temperature of air taken in by the cooling fan A prior cooling request degree calculating means for calculating the prior cooling request degree of the battery based on the background noise level and the preceding noise request level when the preceding cooling request degree calculated by the preceding cooling request degree calculating means is a predetermined value or less. Based on the degree of cooling requirement, the target noise level of the cooling fan is calculated within the background noise level range. A target noise level computing means is characterized by comprising a fan drive control means for controlling the rotation speed of the cooling fan so that the target noise level (claim 1).

  Therefore, when the advance cooling request calculation means calculates the advance cooling request degree of the battery based at least on the charge / discharge current of the battery and the intake air temperature, and the advance cooling request degree is a predetermined value or less, the target noise level calculation means The target noise level of the cooling fan that can be masked with the background noise level is calculated on the basis of the background noise level and the prior cooling requirement level, and the fan drive control means controls the rotation speed of the cooling fan so that the target noise level is reached. Therefore, when the prior cooling request level is equal to or less than a predetermined value, the operating noise of the cooling fan does not increase relative to the background noise of the passenger compartment, and masking with background noise is possible. Therefore, the operation noise of the cooling fan, which is annoying for passengers, is eliminated.

  In addition, the battery has a time lag from when the charge / discharge current flowing through it changes to when its temperature changes, but the battery's pre-cooling request degree is calculated based at least on the charge / discharge current of the battery and the intake air temperature. Therefore, it becomes possible to control the operation mode of the cooling fan when the charge / discharge current of the battery changes, cool the battery before the battery temperature changes, and cope with the time delay of the battery temperature change It becomes possible to do. For this reason, since it becomes possible to cool in anticipation of future heat generation of the battery, it is possible to suppress the fan rotation speed necessary for cooling the battery, compared with the case of cooling after grasping the temperature of the battery. .

  Further, when the preceding cooling request level calculated by the preceding cooling request calculating means becomes larger than a predetermined value, the target noise level may be made constant regardless of the background noise level, and battery cooling may be prioritized. (Claim 2).

In order to facilitate tuning of the cooling fan control, the fan drive control means may be feedback controlled by a linear feedback control loop using a conversion map of fan speed and perceived noise level. 3).
Furthermore, in order to reduce the fluctuation of the battery temperature, the heat storage agent and the radiation fins may be fixed to the battery.

  As described above, according to the first aspect of the present invention, when the degree of prior cooling requirement of the battery calculated based at least on the charging / discharging current of the battery and the intake air temperature is equal to or less than a predetermined value, it is annoying to the passenger. This eliminates the noise generated by the cooling fan, which makes it possible to reduce the fan noise level that can be perceived by the occupant and to control the cooling fan in response to future cooling requirements. Can be cooled.

  In addition, since it is possible to cool in anticipation of future heat generation of the battery, it is possible to reduce the fan rotation speed required for battery cooling compared to the conventional case, and to reduce the power consumption of the cooling fan. Is possible.

  According to the second aspect of the present invention, the target noise level becomes constant regardless of the background noise level when the degree of the preceding cooling request calculated by the preceding cooling request calculating means is greater than the predetermined value, so that noise reduction is achieved. It is possible to prioritize the cooling of the battery in preference to the above.

  According to the third aspect of the present invention, since the cooling fan drive is feedback-controlled by the linear feedback control loop using the conversion map of the fan speed and the perceived noise level, tuning of the cooling fan drive control is easy. Can be performed.

  According to the fourth aspect of the invention, since the heat storage agent and the heat radiation fin are fixed to the battery, it is possible to reduce the fluctuation of the battery temperature.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best embodiment of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows a configuration example of a cooling device for cooling a battery mounted on a vehicle. This battery cooling device ventilates a battery 3 and a cooling fan 4 through a housing case 2 in which an air passage 1 is formed. The air is sucked from the wind inlet 2a of the housing case 2 by the rotation of the cooling fan 4, and the sucked air passes through the periphery of the battery 3 and is sent out from the wind outlet 2b. The battery 3 is configured to be cooled by the air flowing through the ventilation passage 1.

  The control unit 10 is a known unit including a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), an input / output port (I / O), and the like. A current sensor 11 for detecting the discharge current Ib, an intake air temperature sensor 12 for detecting the temperature (intake air temperature) of the intake air sucked into the housing case 2, a battery temperature sensor 13 for detecting the temperature of the battery 3, and a vehicle speed for detecting the vehicle speed. Various signals are input from the sensor 14 and a blower speed sensor 15 for detecting the blower speed of an air conditioner (not shown), and the signals from the various sensors are processed in accordance with a predetermined program given to the ROM. The power supply to the motor 4a of the cooling fan 4 is turned on / off, the rotational speed is controlled, and the like.

  The control unit 10 includes, as its processing functions, a preceding cooling request degree calculation unit 20 that calculates a preceding cooling request degree k of the battery 3 based on detection signals from the current sensor 11, the intake air temperature sensor 12, and the battery temperature sensor 13, and a vehicle speed. Based on detection signals from the sensor 14 and the blower speed sensor 15, an allowable noise level calculation unit 21 for calculating an allowable noise level NB0 in the vehicle interior, the preceding cooling request degree k calculated by the preceding cooling request degree calculation unit 20, and the allowable noise. A target noise level calculation unit 22 that calculates the target noise level NB of the cooling fan 4 based on the allowable noise level NB0 calculated by the level calculation unit 21, and a cooling fan to converge the noise level of the cooling fan 4 to the target noise level. And a fan rotation speed calculation unit 23 for calculating a rotation speed Vf of 4. By the drive circuit 16 so that to drive the cooling fan 4 at a rotational speed Vf calculated in the fan rotation speed calculation unit 23.

  As shown in FIG. 2, the allowable noise level calculation unit 21 calculates the noise level in the vehicle interior corresponding to the vehicle speed from the vehicle speed based on the conversion map 31 between the vehicle speed and the noise level of the vehicle compartment obtained in advance by experiments or the like. Further, based on the conversion map 32 of the air conditioner blower rotation speed (air conditioner blower speed) and the passenger compartment noise level obtained in advance through experiments or the like, the noise level in the passenger compartment is calculated from the air conditioner blower speed. By adding the noise level, the background noise level in the vehicle interior excluding the noise caused by the rotation of the cooling fan 4 is calculated as the allowable noise level NB0.

  The prior cooling request degree calculation unit 20 performs the calculation process shown in FIGS. 3 and 4, and the amount of heat generated by the battery 3 is proportional to the square of the charge / discharge current Ib. By calculating the calorific value of the battery 3 based on the discharge current Ib, adding the intake air temperature Tin detected by the intake air temperature sensor 12 to the calorific value, and integrating it taking into account the amount of heat escaping from the battery 3 (leakage integration) The estimated heat generation temperature ΔT caused by the amount of heat generated from the battery 3 is calculated. Based on the estimated heat generation temperature ΔT of the battery 3 and the current temperature of the battery (battery temperature detected by the battery temperature sensor) Tb, the advance cooling request degree k is calculated based on the characteristic line also shown in FIG. . That is, a characteristic line (indicated by a solid line) indicating the relationship between the current battery temperature Tb and the prior cooling request degree k is shifted by the estimated heat generation temperature ΔT, and the current battery temperature Tb detected by the battery temperature sensor 13 is changed. The cooling request degree k of the battery 3 in anticipation of future heat generation is calculated.

  Therefore, as the estimated heat generation temperature ΔT is larger, the shift amount of the characteristic line is larger, and the advance cooling request degree k is larger even if the battery temperature Tb is the same.

  The target noise level calculation unit 22 calculates the target noise level NB according to the flowchart shown in FIG. 5 based on the preceding cooling request degree k calculated as described above and the allowable noise level NB0. The following description will be made based on this flowchart. In order to calculate the target noise level NB, the state variable S is used to represent the current state of the battery 3, and the initial value of the state variable S is set to zero. Start processing.

  First, in order to reflect the current state in the state variable S, the size of the state variable is determined in step 50. If the state variable S is 0, the process proceeds to step 52. If the state variable S is 1, the process proceeds to step 54. If the state variable S is 2, the process proceeds to step 56 to reset the state variable S based on the magnitude of the preceding cooling request degree k.

  That is, in step 52, if k is 1 or less shown in FIG. 4 (k ≦ 1), the operation state S of the cooling fan 4 is set to “0” indicating the intermittent operation state, and k is greater than 1. If there is (1 <k), the operation state S of the cooling fan 4 is set to “1” indicating a low-speed continuous operation (Low continuous operation) state.

  In step 54, if k is smaller than 1−Δh in consideration of the hysteresis width Δh (k <1−Δh), the operation state S of the cooling fan 4 is set to “0” indicating the intermittent operation state. If k is 1−Δh or more and smaller than C shown in FIG. 4 (1−Δh ≦ k <C), the operation state S of the cooling fan 4 is set to the low-speed continuous operation (Low continuous operation) state. If k is equal to or greater than C (C ≦ k), the operation state of the cooling fan 4 is set to “2” indicating a high-speed continuous operation (Hi continuous operation) state.

  In step 56, if k is smaller than C−Δh (k <C−Δh), the operation state S of the cooling fan 4 is set to “1” indicating the low-speed continuous operation (Low continuous operation) state. (Step 68) If k is equal to or greater than C−Δh (C−Δh ≦ k), the operation state S of the cooling fan 4 is set to “2” indicating a high-speed continuous operation (Hi continuous operation) state (Step 70). ).

Then, the state variable S reset as described above is discriminated (step 72), and the target noise level NB is set as follows.
That is, when the state variable S is set to “0” indicating the intermittent operation state of the cooling fan 4, the target noise level NB is set to the prior cooling request degree k and the allowable noise level (background noise level) NB0. When the noise level represented by the product is set (step 74) and the state variable S is set to "1" indicating the low-speed continuous operation (low continuous operation) state of the cooling fan 4, the target noise level NB Is set to the limit value of the permissible level, that is, the limit level NBLow (the noise level at which NB = NB0) that does not exceed the background noise level (step 76), and the state variable S is the high-speed continuous operation (Hi When set to “2” indicating the continuous operation) state, the target noise level NB is set to the maximum value NBmax exceeding the background noise level in order to give priority to cooling of the battery 3 regardless of the allowable noise level. The (Step 78).

  Accordingly, the relationship between the prior cooling request level k and the target noise level NB is as shown in FIG. 6, and if the prior cooling request level k is small, the target noise level NB is kept below the background noise level. If the prior cooling request degree k is large, the target noise level is set to be higher than the background noise level, and the cooling of the battery 3 is promoted by giving priority to the rotation of the cooling fan 4.

In the fan rotation speed calculation unit 23, a subtractor 36 for calculating a deviation between the target noise level NB output from the target noise level calculation unit 22 and the noise level output from the fan speed-noise conversion unit 35; A PI control unit 37 that outputs a fan speed Vf by proportional-integral control calculation based on the deviation calculated by the subtractor 36 is used to perform PI control by feedback control.
Here, the fan speed-noise conversion unit 35 has a conversion map between the fan speed and the perceived noise level created in advance by experiments or the like, and converts the fan speed Vf output from the PI control unit 37 into a perceived noise level. Then, it is output to the subtracter 36 as a feedback value.

  In the above control, assuming that the charging / discharging current Ib and the vehicle speed of the battery 3 change as shown in FIG. 7, the prior cooling request degree k changes following the change of the charging / discharging current Ib of the battery. When the charging / discharging current of the battery 3 frequently flows, the leakage integral value increases and the estimated heat generation temperature ΔT of the battery 3 increases, so that the relational characteristic shown in FIG. 4 increases.

  Further, the allowable noise level NB0 changes following the conversion of the vehicle speed. The target noise level NB is a noise level represented by the product of the prior cooling requirement degree k and the allowable noise level (background noise level) NB when k is small (when it is 1 or less), and k is greater than 1. Then, the target noise level NB is fixed to a limit level NBLow (a noise level at which NB = NB0) that does not exceed the background noise level, and when k is large (when larger than C), the target noise level NB Is fixed at the maximum value NBmax exceeding the background noise level.

  Accordingly, while the degree of prior cooling request k is small, the target noise level is set according to the change in the allowable noise level, and the rotational speed of the cooling fan 4 changes following this target noise level. When it becomes large, the cooling fan is rotated within a range that can be masked by background noise, and the battery 3 is pre-cooled (fan operation # 1 portion in the figure). Further, when the required cooling level k exceeds 1 and the allowable noise level NB0 is large, noise caused by the rotation of the cooling fan 3 can be masked by background noise (in the figure, the fan Operation # 2), for example, if the allowable noise level decreases and the advance cooling request level k increases beyond C, the cooling of the battery 3 cannot catch up. In order to promote the cooling of the cooling fan 3, the rotation speed of the cooling fan 4 is set large (in the figure, the part of fan operation # 3). In this case, the driving sound of the cooling fan 4 is recognized by the occupant, but the battery 3 is cooled as much as possible when the operating sound of the cooling fan 4 has a large allowable noise level that can be masked by background noise. Therefore, the battery temperature Tb can be kept low as indicated by the solid line.

  When the cooling fan is controlled based on the battery temperature Tb that follows the current change of the battery 3 with a delay, the preceding cooling is not performed, and therefore the battery temperature Tb changes as indicated by a one-dot chain line. In order to cool such a battery 3, it is necessary to increase the rotation speed of the cooling fan 4. However, as shown in the present embodiment, the prior cooling request degree k reflecting the charge / discharge current change of the battery 3 is increased. When the cooling fan 4 is controlled based on the above, the cooling fan 3 can be operated as much as possible within the range where the operation noise does not exceed the background noise when the allowable noise level is high, and the battery 3 can be preliminarily cooled. It is possible to keep the battery temperature Tb low while preventing the occupant from recognizing driving noise.

Further, since the preceding cooling is performed, it is not necessary to drive the cooling fan 4 excessively in order to cool the battery 3, and the power consumption of the cooling fan 4 can be reduced as compared with the conventional case.
Furthermore, when the degree of cooling request of the battery 3 is excessively large, it is possible to prioritize cooling of the battery 3 ignoring the need for noise reduction, as in the past, in order to quickly cool the battery 3. It becomes.

  Furthermore, in the above configuration example, a linear feedback control loop using a map representing the relationship between the fan speed and the perceived noise level is used in the feedback system provided in the fan rotation speed calculation unit 23. Tuning is facilitated when the cooling fan 4 is driven and controlled at a fan speed corresponding to the noise level.

The battery 3 may be housed in the housing case 2 alone, but may be housed in the housing case 3 with the heat storage material and the radiation fins attached.
Specifically, as shown in FIG. 8, a heat storage material 41 is attached in contact with the battery 3, and for example, corrugated radiating fins 42 are arranged on the heat storage material 41 at a predetermined interval from the heat storage agent 41. The battery 3, the heat storage material 41, and the heat radiation fins 42 are fixed and integrated with a band 44 and the like, and the ventilation path of the heat radiation fins 42 is connected to the end plate 43. You may make it arrange | position according to.

  By adopting such a configuration, the heat storage material 4 can be pre-cooled together with the battery 3 by blowing the cooling fan 4 at the time of pre-cooling. Therefore, even when the charge / discharge current of the battery 3 increases later, the battery temperature The rise in Tb can be effectively suppressed over a long period of time, and the fluctuation range of the battery temperature Tb can be reduced.

FIG. 1 is a block diagram showing an overall configuration example of an in-vehicle battery cooling device according to the present invention. FIG. 2 is a block diagram showing an example of calculation processing of the allowable noise level calculation unit of FIG. FIG. 3 is a block diagram illustrating an example of calculation processing of the preceding cooling request degree calculation unit in FIG. 1. FIG. 4 is a diagram for explaining an example of map calculation processing for calculating the degree of advance cooling request using a map from the heat generation estimated temperature ΔT and the battery temperature Tb. FIG. 5 is a flowchart showing an example of calculation processing of the target noise level calculation unit of FIG. FIG. 6 is a diagram showing the relationship between the prior cooling request level k and the target noise level NB. FIG. 7 is a diagram illustrating changes with time of each parameter with respect to changes in the charge / discharge current of the battery and changes in the vehicle speed. FIG. 8 is a view showing a state in which a heat storage material and a cooling fin are attached to a battery. FIG. 8A is a perspective view thereof, and FIG. 8B is a front view thereof.

Explanation of symbols

3 Battery 4 Cooling fan 41 Thermal storage agent 42 Radiation fin

Claims (4)

In-vehicle battery cooling device comprising a battery mounted on a vehicle and a cooling fan for cooling the battery, and controlling an operation mode of the cooling fan.
An allowable noise level calculation means for calculating a background noise level in the passenger compartment excluding noise generated by rotation of the cooling fan;
A pre-cooling request degree calculating means for calculating the pre-cooling request degree of the battery based at least on the charge / discharge current of the battery and the temperature of the air taken in by the cooling fan;
When the preceding cooling request degree calculated by the preceding cooling request degree calculating means is less than or equal to a predetermined value, the cooling fan within the background noise level range based on the background noise level and the preceding cooling request degree. Target noise level calculation means for calculating the target noise level;
An in-vehicle battery cooling device comprising fan drive control means for controlling the rotational speed of the cooling fan so as to achieve the target noise level. 2. The on-vehicle device according to claim 1, wherein when the degree of advance cooling request calculated by the advance cooling request calculating means is greater than a predetermined value, the target noise level is made constant regardless of the background noise level. Battery cooling device. 2. The on-vehicle battery cooling device according to claim 1, wherein the fan drive control means performs feedback control by a linear feedback control loop using a conversion map of fan speed and perceived noise level. The in-vehicle battery cooling device according to claim 1, wherein a regenerator and a radiation fin are fixed to the battery.

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