JP2016115609A - Battery cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery cooling device capable of contributing to the reduction of energy consumption required for battery cooling by achieving efficient operation of battery cooling means to maintain a battery temperature within a proper temperature range.SOLUTION: The temperature transition of a battery (11) is predicted from positional information of own vehicle and route information in a predetermined prediction range of vehicle front. In the cooling control for controlling a battery cooling circuit (20) so that an average temperature becomes an indicated temperature while dispersing battery temperature in a managed temperature width when the battery temperature exceeds a proper temperature range, when a battery use state based on ΣΔSOCin the prediction range is larger than a predetermined value (Yes in S20), operation is put in a cooling mode, and the managed temperature width is made to be a narrow first temperature width, then a quick cooling mode whose prediction range is a narrow first range is selected (S21).SELECTED DRAWING: Figure 6

Description

  The present invention relates to a battery cooling device.

  A battery usually has an appropriate temperature range for use. If the temperature is higher than this temperature range, the performance and product life are reduced. Therefore, as described in Patent Document 1, for example, the temperature of a battery that supplies electric power to a motor serving as a drive source in a hybrid vehicle is estimated based on road information about a travel route, so that the battery is in an appropriate temperature range. There is known a battery cooling device for controlling the temperature.

JP 2006-139963 A

  In the technology described in Patent Document 1, cooling is performed in advance when the battery temperature exceeds an appropriate temperature range. However, the required cooling work amount of the battery according to the use state of the battery according to the traveling state of the vehicle. No consideration is given to changes in (cooling work amount that varies depending on cooling water flow rate and cooling fan output).

  For example, when the battery temperature exceeds the appropriate temperature range, if the battery cooling fan is always driven at the maximum output in order to maintain the appropriate temperature range, more energy than necessary is consumed, resulting in poor efficiency. is there. In addition, when the regenerative operation is continuously performed on a long downhill road, the use of the battery increases according to the traveling state of the vehicle, so that the battery cooling work required per unit time also increases. .

  The present invention has been made to solve such a problem. In order to maintain the battery temperature within an appropriate temperature range, the battery cooling means can be efficiently operated to reduce energy consumption required for battery cooling. An object of the present invention is to provide a battery cooling device capable of reliably responding to a change in required battery cooling work amount according to a traveling state of a vehicle while contributing.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

  The battery cooling device according to this application example is mounted on a vehicle, acquires a battery having a predetermined appropriate temperature range, battery cooling means for cooling the battery, route information in a predetermined prediction range in front of the vehicle, When predicting the driving state of the vehicle at each point on the route, predicting the battery temperature transition, and when the battery temperature transition predicted by the battery temperature prediction means exceeds the appropriate temperature range, A cooling setting means for setting an instruction temperature for the battery cooling means to maintain the temperature of the battery within an appropriate temperature range; and a predetermined management temperature in the prediction range with respect to the instruction temperature set by the cooling setting means. The battery cooling means is controlled so that the average temperature becomes the indicated temperature while having variation within the range. A rejection control unit, a battery usage state estimation unit that estimates a usage state of the battery in the prediction range, and a battery usage state estimated by the battery usage state estimation unit is greater than a predetermined threshold, Management temperature width setting means for setting the management temperature width of the cooling control means to be narrower than in the case where the cooling control means is equal to or less than a threshold.

  According to the present invention using the above means, it is possible to maintain the battery temperature in an appropriate temperature range, realize an efficient operation of the battery cooling means, and contribute to reduction of energy consumption required for battery cooling.

It is a schematic block diagram of the battery cooling device which concerns on one Embodiment of this invention. It is a flowchart showing the battery cooling control routine which ECU of the battery cooling device which concerns on one Embodiment of this invention performs. It is a time chart which shows the example of the temperature transition of a battery. It is a control flow which calculates the control base value and control gain in battery cooling. It is a related figure of the average temperature of a battery temperature in a prediction range, and a cooling work amount. It is a flowchart showing the setting control routine of the management temperature range and prediction range which ECU of the battery cooling device which concerns on one Embodiment of this invention performs.

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

  FIG. 1 is a schematic configuration diagram of a battery cooling device for a hybrid vehicle according to an embodiment of the present invention, which will be described with reference to FIG.

  The hybrid vehicle 1 is configured as a so-called parallel hybrid truck, and is simply referred to as a vehicle in the following description.

  A vehicle 1 is equipped with a diesel engine (hereinafter referred to as an engine) 2 as a driving power source and a motor 3 (electric motor) that can also operate as a generator. A clutch 4 is connected to the output shaft of the engine 2, and an input side of the transmission 5 is connected to the clutch 4 via a rotating shaft of the motor 3. A differential device 7 is connected to the output side of the transmission 5 via a propeller shaft 6, and left and right drive wheels 9 are connected to the differential device 7 via a drive shaft 8.

  Specifically, the motor 3 is a synchronous generator motor including a rotor on which a permanent magnet is attached and a stator on which a three-phase coil is wound, and is connected to a battery 11 via a power converter 10. .

  The power converter 10 can convert DC power from the battery 11 into AC power and supply it to the motor 3, and can rectify AC power from the motor 3 and supply it to the battery 11.

  The vehicle 1 configured as described above travels by transmitting the driving force generated by the engine 2 or the motor 3 by the transmission 5 and then transmitting it to the driving wheels 9. For example, when the vehicle 1 decelerates or travels on a downhill road, the motor 3 operates as a generator by reverse driving from the drive wheel 9 side. The negative driving force generated by the motor 3 is transmitted to the driving wheel 9 side as a braking force, and the AC power generated by the motor 3 is converted into DC power by the power converter 10 and charged to the battery 11. .

  Further, the vehicle 1 is provided with a battery cooling circuit 20 (battery cooling means) for cooling the battery 11. The battery cooling circuit 20 is a so-called water-cooled cooling structure that uses cooling water as a refrigerant. The battery cooling circuit 20 includes a battery 11, a pump 21, a cooling water tank 22, and a radiator 23.

  Specifically, the pump 21 is driven to circulate cooling water in the battery cooling circuit 20. The pump 21 is electrically driven, and the flow rate of the cooling water can be changed by adjusting the rotation speed. In the battery cooling circuit 20 in this embodiment, cooling water circulates from the pump 21 in the order of the battery 11, the cooling water tank 22, and the radiator 23.

  The cooling water tank 22 stores cooling water, and the radiator 23 is a heat exchanger that cools the cooling water by exchanging heat with the outside air. Further, a fan 24 that blows air toward the radiator 23 is disposed in the vicinity of the radiator 23.

  The fan 24 is electrically driven, and the amount of blown air can be varied by adjusting the rotational speed. In the radiator 23, heat exchange with the outside air is promoted by the air blown from the fan 24.

  In the battery cooling circuit 20 configured as described above, when the battery 11 is cooled, the pump 21 is driven so that the cooling water that has absorbed the heat of the battery 11 is sent to the radiator 23. In the radiator 23, the cooling water is cooled by exchanging heat between the cooling water and the outside air. Then, the sufficiently cooled cooling water is sent to the battery 11 again.

  The amount of heat released from the battery 11 by the battery cooling circuit 20 varies according to the drive amount of the pump 21 and the fan 24. For example, if the driving amount of the pump is increased, the circulation rate of the cooling water is increased and the heat dissipation amount of the battery 11 is increased. Further, if the driving amount of the fan is increased, the heat dissipation of the cooling water in the radiator 23 is promoted and the cooling water can be maintained at a low temperature, so that the heat dissipation amount of the battery 11 increases.

  The vehicle 1 includes an ECU 30 that manages the battery 11, including the battery cooling circuit 20. A battery temperature sensor 31 that detects the temperature of the battery 11 and an outside air temperature sensor 32 that detects the outside air temperature outside the vehicle 1 are connected to the ECU 30. Further, the ECU 30 detects the voltage of the battery 11 from the battery 11, the current flowing between the power converter 10 and the battery 11, and calculates the SOC (State Of Charge) of the battery 11 from these detection results. To do.

  The ECU 30 also performs cooling control of the battery 11 using the battery cooling circuit 20. In the cooling control of the battery 11, the ECU 30 predicts the travel of the vehicle 1, predicts a change in the battery temperature corresponding to the travel, and performs the battery cooling control so that the battery temperature is maintained within an appropriate temperature range.

  Specifically, the ECU 30 acquires road environment information (route information) in a predetermined prediction range in the travel route ahead of the host vehicle, and predicts the driving state of the vehicle 1 at each point on the route. Therefore, the ECU 30 is connected to a GPS (Global Positioning System) 33 that acquires position information of the host vehicle and a navigation unit 34 that detects route information ahead of the host vehicle. For example, the navigation unit 34 can store map data, road information, road surface gradient information, and the like in its own storage area, and can receive road traffic information such as traffic jams and traffic regulations from an external communication network.

  2 to 5, FIG. 2 is a flowchart showing a battery cooling control routine executed by the ECU 30, FIG. 3 is a time chart showing an example of a temperature transition of the battery 11, and FIG. FIG. 5 shows a control flow for calculating the control base value and the control gain in the battery cooling. FIG. 5 shows a relationship diagram between the average temperature of the battery temperature and the cooling work amount in the prediction range. The battery cooling control according to the present embodiment will be described with reference to FIGS.

  First, in step S <b> 1, the ECU 30 acquires the position information of the host vehicle from the GPS 33 and acquires road surface gradient information within a predetermined prediction range from the navigation unit 34.

Subsequently, in step S2, the ECU 30 predicts the temperature transition of the battery 11 (battery temperature prediction means). Specifically, the route ahead of the vehicle is classified based on the road surface gradient information acquired in step S1, and the variation of the SOC is predicted from the gradient change on the route expected in each section and the driving state of the vehicle 1. For example, in the downhill road section, it is predicted that the regenerative operation is performed by the motor 3, and the SOC is predicted to rise. Further, in a section of an uphill road or a flat road, if the SOC predicted in the section is relatively large, it is predicted that the motor 3 alone or both the motor 3 and the engine 2 will travel, and the SOC is consumed. I predict. On the other hand, if the flat road continues and regenerative operation cannot be expected and the SOC is small, it is predicted that the engine 2 will run alone, so the SOC is predicted to hardly increase or decrease. Then, the ECU 30 predicts the temperature change of the battery 11 from such SOC fluctuation. For example, since the SOC is calculated from the current history, it can be calculated by ΔSOC ² (the square of the amount of change in SOC) in the same manner as I ² R (the square of the current × the internal resistance) for calculating the heat generation amount.

  In step S3, the ECU 30 determines whether or not the predicted battery temperature exceeds a predetermined appropriate temperature range of the battery 11. If the determination result is false (No), that is, if the battery temperature changes within the appropriate temperature range, it is not necessary to cool the battery, and the routine returns.

  On the other hand, as shown in FIG. 3, in the transition of the predicted battery temperature, if the appropriate temperature range is exceeded unless battery cooling is performed, the determination result in step S3 is true (Yes), and the battery cooling is not performed. Proceed to step S4 to do so.

  In step S4, the ECU 30 sets an instruction temperature TTarget and a management temperature range TBand for cooling the battery (cooling setting means). The instruction temperature TTarget here is set to a temperature for keeping the battery temperature within an appropriate temperature range, and is set to, for example, an upper limit value TLimit of the appropriate temperature range (TTarget = TLimit). Further, the management temperature range corresponds to a range that allows variation in battery temperature, and is set according to the usage state of the battery 11 in the prediction range, as will be described in detail later.

  In subsequent step S5, the ECU 30 calculates a control base value TBase and a control gain TGain for obtaining a cooling command value for the battery cooling circuit 20 from the instruction temperature TTarget and the management temperature width TBand according to the control flow shown in FIG.

Specifically, as shown in FIG. 4, the ECU 30 detects the indicated temperature TTarget, the management temperature range TBand, ΣΔSOC ² (the integrated value of the square of the change amount of the SOC) within the prediction range, and the outside air temperature calculated by the outside air temperature sensor 32. The control gain TGain is calculated from the first map based on TAmbient and vehicle speed. Then, a control base value TBase is calculated from this control gain TGain, a second map based on the command temperature TTarget, ΣΔSOC ² within the prediction range, the outside air temperature TAmbient, and the vehicle speed. The first map and the second map take into account that the battery temperature is affected by external factors such as the driving pattern of the vehicle 1 and the outside air temperature TAmbient, and in accordance with these external factors in advance for the indicated temperature TTarget and the management temperature range TBand. The appropriate control base value TBase and control gain TGain are obtained by experiment and set in advance.

  Here, the control base value TBase and the control gain TGain will be described based on the relationship diagram between the average temperature of the battery temperature and the cooling work amount in the prediction range of FIG. In the relationship diagram, the outside air temperature is a constant value TAmbient1 (for example, 35 ° C.).

  In the figure, the black dots indicate the relationship between the battery average temperature TAve and the cooling work E when the management temperature width is 0, that is, when the control gain TGain is 100%. In this case, as indicated by the alternate long and short dash line, the cooling work E tends to decrease as the battery average temperature TAve increases, that is, as the difference between the battery temperature and the outside air temperature TAmbient1 increases.

  On the other hand, the white point indicates the relationship between the battery average temperature TAve and the cooling work E when the predetermined management temperature width TBand1 is given to the black point condition. In this case, as shown by a two-dot chain line, the cooling work as a whole becomes lower than the one-dot chain line. In addition, the cooling work E tends to decrease as the battery average temperature TAve increases so as to be parallel to the alternate long and short dash line.

  Here, in FIG. 5, the black point when the management temperature width is set to 0 and the instruction temperature TTarget is controlled as the upper limit value TLimit of the appropriate temperature range is the point a. In this case, as shown in the normal distribution diagram (a), the distribution of the battery temperature within the predicted range is controlled by the command temperature TTarget at almost all times within the predicted range, and the average value TAve1 is almost equal to the command temperature. Same as TTarget. The actual temperature width at point a is relatively narrow ΔTb1, and the cooling work is E1.

  On the other hand, if the specified temperature TTarget is set to the upper limit value TLimit of the appropriate temperature range and has a predetermined management temperature range TBand1, the white point b is obtained. In this case, as shown in the normal distribution diagram (b), the battery temperature varies more than in the case of the black spot a, and the actual temperature range extends to ΔTb2 (ΔTb2> ΔTb1). The average temperature TAve2 slightly increases (TAve2> TAve1), while the cooling work amount decreases from E1 to E2 (E2 <E1). In other words, by providing the management temperature width TBand1 and allowing variation in battery temperature, the cooling accuracy of the battery 11 by the battery cooling circuit 20 is lowered while the cooling work is reduced.

  The ECU 30 maintains the management temperature range TBand1 while maintaining the management temperature range TBand1 while the average temperature TAve of the battery 11 increases and deviates from the instruction temperature TTarget by having the management temperature range TBand1. Thus, the control base value TBase and the control gain TGain are set by the first map and the second map. That is, as shown by the white point c in FIG. 5, the average temperature TAve3 is set as the instruction temperature TTarget along the tendency from the white point b to the two-dot chain line. Then, the cooling work E3 at the white point c is higher than the cooling work E2 at the white point b, but is lower than the cooling work E1 at the black point a when the management temperature range is not given. Realized (E3 <E1).

  After setting the control base value TBase and the control gain TGain, the ECU 30 cools the battery using a value obtained by multiplying the control base value TBase and the control gain TGain as a cooling command value (= TBase × TGain) in the subsequent step S6. The circuit 20 is controlled (cooling control means). Specifically, the ECU 30 drives and controls the pump 21 and the fan 24 according to the cooling command value so that the average temperature TAve becomes the command temperature TTarget while the battery temperature varies within the management temperature range TBand within a predetermined prediction range. To do.

  As described above, the ECU 30 predicts the temperature transition of the battery 11 and, when exceeding the appropriate temperature range, suppresses the battery temperature to the instruction temperature TTarget before exceeding the appropriate temperature, thereby ensuring the battery temperature. Is maintained within the proper temperature range.

  Furthermore, the ECU 30 in this embodiment sets the management temperature range in step S3 of FIG. 2 according to the usage state of the battery 11 and the predetermined prediction range of step S1 according to the environmental state of the battery 11, respectively. change.

  Specifically, FIG. 6 shows a flowchart showing a control routine for setting the management temperature range and the prediction range executed by the ECU 30.

  As a premise, the ECU 30 stores two temperature ranges, a first temperature range that is a relatively narrow range as the management temperature range and a second temperature range that is wider than the first temperature range. As shown in FIG. 3, as the prediction range, a base range serving as a base, a first range shorter than the base range, and a second range longer than the base range are stored in the ECU 30. And ECU30 is equipped with three types of cooling modes from which the combination of these management temperature widths and prediction ranges differs.

As shown in the flowchart of FIG. 6, first, as step S20, the ECU 30 calculates ΣΔSOC ² (integrated value of the square of the amount of change in SOC) of the battery 11 in the prediction range (for example, the base range), and the ΣΔSOC ² is predetermined. It is determined whether or not the predetermined value is larger. In this determination, the usage state of the battery 11 is estimated from the current flowing in and out of the battery 11 (battery usage state estimation means). The predetermined value here is set to, for example, ΣΔSOC ² where the battery temperature may exceed the appropriate temperature range. Therefore, when the regenerative operation is continuously performed on a long downhill road or when the power running operation with the motor 3 is performed for a long time, ΣΔSOC ² becomes larger than a predetermined value. If ShigumaderutaSOC ² is larger than the predetermined value, the determination result goes true (Yes), and the step S21.

In step S21, the ECU 30 selects the rapid cooling mode in which the battery 11 is cooled early as the battery cooling mode. In the rapid cooling mode, the first temperature range having a narrow management temperature range is set and the first range having a short prediction range is set (management temperature range setting means). The first temperature range corresponds to, for example, a temperature range in which the above-described control gain TGain is 100% or close to 100%, and the battery temperature is controlled almost according to the instruction temperature TTarget with almost no variation in battery temperature. Then, by setting the prediction range to the short first range, since the tendency of ΔSOC ^{2 for} a short period from the present is used, a large over-temperature amount is estimated, and the required cooling work amount is increased, and the prediction frequency is increased. Since the feedback correction interval of the increased cooling work amount is shortened, the battery temperature is cooled to the indicated temperature in a short period.

  Therefore, the ECU 30 according to the present embodiment changes the battery usage state depending on the running state such as when the regenerative operation is continuously performed on a long downhill road, and the battery cooling work required for a unit time increases. When predicted, the battery 11 can be rapidly cooled by providing a rapid cooling mode in which the management temperature range is set narrower than the cooling mode described later. Thereby, the change of the cooling work amount of the battery 11 according to the traveling state of the vehicle can be reliably handled.

On the other hand, if the determination result at Step S20 is if false (No), i.e. if ShigumaderutaSOC ² is a normal battery state of use of less than a predetermined value, the process proceeds to step S22.

  In step S22, the ECU 30 detects the outside air temperature TAmbient from the outside air temperature sensor 32, and determines whether or not the outside air temperature TAmbient is lower than a predetermined temperature. The predetermined temperature is set to a relatively low temperature with respect to the appropriate temperature range of the battery 11, and when the outside air temperature TAmbient is a low temperature state lower than the predetermined temperature, the determination result is true (Yes), Proceed to step S23.

  In step S23, the ECU 30 selects the low temperature mode corresponding to the battery 11 in the low temperature state as the battery cooling mode. In the low temperature mode, since the difference between the battery 11 and the outside air temperature is large and the environment is easy to cool, the second temperature range having a wide management temperature range is set to the second range having a long predicted range (management temperature range setting means). ). By widening the management temperature range in this way, the above-described control gain TGain is lowered, and variation in battery temperature is allowed and the cooling work E is reduced. And since the temperature of the battery 11 is cooled to instruction | indication temperature TTarget over a long time by extending a prediction range, a cooling work amount can be reduced more.

  On the other hand, if the determination result in step S22 is false (No), that is, if the vehicle is in an environment where the outside air temperature is equal to or higher than a predetermined temperature, the process proceeds to step S24.

  In step S24, the ECU 30 selects the normal mode as the battery cooling mode. In the normal mode, the second temperature range with a wide management temperature range is set, and the predicted range is set as the base range (management temperature range setting means). Thus, the cooling work amount E can be reduced by setting the management temperature range to the second temperature range.

  As described above, after selecting the cooling mode in steps S21, S23, and S24 and determining the management temperature range and the prediction range, the routine is returned.

  And ECU30 performs battery cooling control shown in FIG. 2 mentioned above in the management temperature range and prediction range according to cooling mode.

As described above, the battery 11 is used from the ΣΔSOC ^2, and the battery use state changes depending on the running state such as when the regenerative operation is continuously performed on a long downhill road. When an increase in the cooling work amount is predicted, the battery 11 is cooled early by selecting the rapid cooling mode, so that the battery temperature can be reliably maintained within an appropriate temperature range, and the battery performance is maintained. be able to. On the other hand, when the load of the battery 11 is not large, the battery 11 can be efficiently cooled by providing a management temperature range and extending the prediction range, and energy consumption required for battery cooling can be reduced. it can.

  Further, when the outside air temperature is low, the battery temperature can be efficiently maintained within the appropriate temperature range by taking a long time by extending the prediction range.

  Although the description of the embodiment of the battery cooling device according to the present invention is finished above, the embodiment is not limited to the above embodiment.

  The devices provided in the battery cooling circuit 20 of the above embodiment are not limited to those described above, and the arrangement of each device is not limited to this, and other devices may be provided or the arrangement may be changed. Also good. Moreover, although the battery cooling circuit 20 of the said embodiment is a water cooling type, the air cooling type which drives a fan according to a cooling command value may be sufficient.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Engine 3 Motor 4 Clutch 5 Transmission 11 Battery 20 Battery cooling circuit (battery cooling means)
21 pump 22 cooling water tank 23 radiator 30 ECU (battery temperature prediction means, cooling setting means, cooling control means, battery use state estimation means, management temperature range setting means)
31 Battery temperature sensor 32 Outside temperature sensor 33 GPS
34 Navigation unit

Claims (1)

A battery mounted on the vehicle and having a predetermined appropriate temperature range;
Battery cooling means for cooling the battery;
Battery temperature prediction means for acquiring route information in a predetermined prediction range ahead of the vehicle, predicting the driving state of the vehicle at each point on the route, and predicting the battery temperature transition;
When the battery temperature transition predicted by the battery temperature prediction unit exceeds the appropriate temperature range, a cooling setting unit that sets an instruction temperature for the battery cooling unit to maintain the temperature of the battery within the appropriate temperature range;
Cooling control means for controlling the battery cooling means so that an average temperature becomes the indicated temperature while having a variation within a predetermined management temperature range in the predicted range with respect to the indicated temperature set by the cooling setting means. ,
Battery usage state estimation means for estimating a usage state of the battery in the prediction range;
When the battery usage state estimated by the battery usage state estimation unit is larger than a predetermined threshold value, a management temperature range setting unit that sets the management temperature range of the cooling control unit to be narrower than the threshold value or less. When,
A battery cooling device.

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