JPH09289701A - Output controller of electric automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the output controller of an electric automobile which can prevent the unnecessary deceleration caused by the capacity setting of a blower and suppress the excessive rise of the battery temperature. SOLUTION: This is an output controller mounted on an electric automobile which has a vehicle propulsive motor 70, a plurality of battery modules 2, a blower 20 which sends air to a battery case 10, and a plurality of battery temperature sensors 30 which detect the battery temperature of each battery module, and this is equipped with a limit threshold temperature changing means 40 which varies the first threshold temperature to start the output limitation of the motor and the second threshold temperature to begin to maintain the output of the motor to its minimum, according to the temperature difference between the battery modules 2. The magnitude of the battery load is judged by the temperature difference between the battery modules 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output control device for a propulsion motor of an electric vehicle equipped with a secondary battery pack.

[0002]

2. Description of the Related Art In addition to lead batteries, nickel-based batteries such as nickel-cadmium batteries and lithium-based batteries such as lithium-ion batteries are being adopted as storage batteries for electric vehicles. Since it is accompanied by an exothermic reaction during charging, it needs to be cooled during running.

As a cooling device for a battery for an electric vehicle of this type, a cooling fan (hereinafter, also referred to as a blower) has hitherto been used.
However, the battery load that causes a rise in the battery temperature depends on how the electric vehicle runs, that is, the running environment of the electric vehicle, and it is possible to drive in an urban area. In most electric vehicles, the load on the battery is rarely high.

Therefore, assuming all driving environments,
In order to support all these driving environments, that is, assuming that the possibility of running under high load is not zero even if the load is low, it is not possible to set the capacity of the cooling fan to the maximum. However, it is not preferable in terms of driving efficiency of the fan, and also in terms of installation space and weight of the cooling fan.

Therefore, the capacity of the cooling fan is set on the assumption that the vehicle is generally driven in urban areas, and the output of the propulsion motor is limited to increase the battery temperature for high loads such as high-speed traveling. It is being suppressed. For example, the battery surface temperature is detected by a temperature sensor provided in the battery, and when the maximum value of the battery surface temperature reaches the first threshold temperature T _li shown in FIG. 5, the output of the propulsion motor is started to be limited, and the maximum output corresponding to the remaining capacity of the battery at the time, yet the maximum value of the battery temperature, reaches the second threshold temperature T _lf, is limited to the minimum output of the degree that the vehicle can move. As a result, the minimum required blower is sufficient, the installation space, cost, and weight are favorable, and the drive efficiency of the blower is also improved.

[0006]

However, in the above-mentioned conventional output control device for an electric vehicle, since the battery surface temperature is simply detected, as shown in FIG. 6, a low load in which the battery temperature hardly rises. Even though the vehicle is traveling, if the battery temperature exceeds the first threshold temperature T _li because the outside air temperature is high, the output of the propulsion motor is limited. That is,
Even when there is almost no possibility of reaching the upper limit temperature T _lmax of the battery, the output limit of the propulsion motor is started just as the battery temperature reaches the first threshold temperature T _li , and as a result, This may give an uncomfortable feeling to the occupant.

Further, as shown in FIG. 7, when traveling at an extremely high load, the output of the propulsion motor is limited, but in the conventional limiting method, only a static factor such as the battery temperature is used. Since only the detection is performed and no dynamic factors such as the rate of increase in battery temperature are taken into consideration, the battery temperature may rise more than expected and exceed the upper limit operating temperature T _lmax .

The present invention has been made in view of the above problems of the prior art, and it is possible to prevent unnecessary deceleration due to the setting of the capacity of the blower and to suppress an excessive rise in battery temperature. An object is to provide an output control device for a vehicle.

[0009]

In order to achieve the above object, an output control device for an electric vehicle according to the present invention as set forth in claim 1 comprises a motor as a propulsion source for the vehicle and a plurality of power sources for the motor. A battery module, a case that houses the plurality of battery modules, a blower that blows cooling air to the case, and a plurality of battery temperature sensors that detect the battery temperature of each of the battery modules are mounted on an electric vehicle,
In an output control device for an electric vehicle that controls the output of the motor based on each battery temperature detected by the plurality of battery temperature sensors, a first threshold temperature for starting output limitation of the motor, and an output of the motor And a second threshold temperature that starts to be maintained to a minimum, the limit threshold temperature changing means for varying the second threshold temperature according to each battery temperature.

In the output control device for an electric vehicle according to the first aspect of the present invention, the output of the motor is limited based on the battery temperature, and the insufficient capacity of the blower is compensated to suppress an excessive rise in the battery temperature. That is, when the battery temperature detected by the battery temperature sensor reaches the first threshold temperature, the output limitation of the motor is started, and when the battery temperature further rises and reaches the second threshold temperature, the motor temperature is reduced. The output is maintained at a minimum, but the first threshold temperature and the second threshold temperature are not fixed values, but are varied according to the battery temperature of each battery module.

In this case, the partial cooling phenomenon by the blower is utilized. That is, when the battery load is large, the output of the blower also becomes large, but when the output of the blower is large, the batteries in the vicinity of the blower are easily cooled, so uneven cooling occurs in each battery module, and the battery temperature of each battery module is increased. A temperature difference occurs. On the other hand, when the battery load is small, the output of the blower is also small, and the battery temperatures of the battery modules are almost equal. By utilizing such a phenomenon, the load state of the battery is judged, and when the battery load is large, the first threshold temperature and the second threshold temperature are set low, while when the battery load is small, the first threshold temperature and the second threshold temperature are set low. The threshold temperature and the second threshold temperature are set high.

As described above, in the output control device for the electric vehicle according to the first aspect, the first threshold temperature and the second threshold temperature are changed in consideration of the battery load, so that even if the battery temperature is high, When the load is small, the first threshold temperature and the second threshold temperature are set high, and unnecessary output limitation of the motor is not performed. Further, when the battery load is large, such as when the vehicle runs at a high speed suddenly, the first threshold temperature and the second threshold temperature are set low, so that the output of the motor is reduced before the upper limit temperature of the battery is reached. The temperature can be limited and an excessive temperature rise can be suppressed.

Further, since the battery temperature changes very slowly, it is not necessary to prepare a complicated control map or the like for controlling the output of the motor. Therefore, practical application of the output control device for an electric vehicle according to the first aspect can be greatly expected.

In the output control device for an electric vehicle according to claim 1, the limiting threshold temperature changing means is based on each battery temperature, in other words, has some relation with each battery temperature, and has a first threshold temperature and a second threshold temperature. Although the temperature is changed, the specific content thereof is not particularly limited. For example, in the output control device of the electric vehicle according to claim 2, the limiting threshold temperature changing means is configured to change the first threshold temperature based on a temperature difference between the maximum battery temperature and the minimum battery temperature of the plurality of battery modules. And varying the second threshold temperature.

In the output control device for an electric vehicle according to the second aspect, attention is paid to the point that the maximum temperature difference between the battery modules correlates with the magnitude of the battery load. That is, when the battery load is large, the blower is driven with a large output, which causes uneven cooling between the battery modules. Therefore, the temperature difference between the maximum battery temperature and the minimum battery temperature of the battery module becomes large, and in this case, the limiting threshold temperature changing means sets the first threshold temperature and the second threshold temperature low. on the other hand,
When the battery load is small, the blower stops or is driven with a small output, so that uneven cooling does not occur between the battery modules. Therefore, the temperature difference between the maximum battery temperature and the minimum battery temperature of the battery module becomes small, and in this case, the first threshold temperature and the second threshold temperature are set high.

In the output control device for an electric vehicle according to the first aspect, the control content of the limiting threshold temperature changing means can be modified in various ways. For example, in the output control device for an electric vehicle according to claim 3, the limiting threshold temperature changing means is configured to change the first threshold temperature and the second threshold temperature based on variations in battery temperatures of the plurality of battery modules. And are varied.

In the output control device for an electric vehicle according to the present invention, the battery load is judged not by the temperature difference between the maximum battery temperature and the minimum battery temperature of the battery module but by the variation of the battery temperature of the battery module. That is, like the output control device for an electric vehicle according to claim 2 described above, when the battery load is large, the blower drives with a large output, which causes uneven cooling between the battery modules. Therefore, the variation in the battery temperature of the battery module becomes large, and in this case, the limiting threshold temperature changing means sets the first threshold temperature and the second threshold temperature low. On the other hand, when the battery load is small, the blower stops or is driven with a slight output, and uneven cooling does not occur between the battery modules. Therefore, the variation in the battery temperature of the battery module becomes small, and in this case, the first threshold temperature and the second threshold temperature are set high.

In the output control device for an electric vehicle according to any one of claims 2 to 3, the limit threshold temperature is changed based on the difference or variation in the battery temperature of the battery module. However, the output control device for the electric vehicle according to claim 4 Is characterized in that the limiting threshold temperature changing means changes the first threshold temperature and the second threshold temperature based on a temperature change rate of battery temperatures of the plurality of battery modules. Here, the rate of change of the battery temperature is a value obtained by dividing the temperature difference obtained by subtracting the battery temperature T _b-1 before the unit time τ from the current battery temperature T _b by the unit time (T _b
-T _b-1 ) / τ.

In the output control device for an electric vehicle according to the present invention, the battery load is judged by the rate of change of the battery temperature rather than the state of partial cooling by the blower. That is, when the battery load is large, the rate of change in battery temperature increases to the positive side, and in this case, the first threshold temperature and the second threshold temperature are set low by the limiting threshold temperature changing means. On the other hand, when the battery load is small, the rate of change in battery temperature decreases on the plus side, so in this case, the first threshold temperature and the second threshold temperature are set high. In the output control device for an electric vehicle according to the present invention, since the rate of change in battery temperature is used instead of utilizing the partial cooling phenomenon by the blower, there is a case where cooling is not performed due to a failure of the blower. Can also determine the battery load.

In the output control device for an electric vehicle according to any one of claims 1 to 4, the type of battery is not particularly limited, and in addition to lead batteries, nickel-based batteries such as nickel-cadmium batteries, sodium-sulfur batteries, lithium-ion batteries, etc. A lithium battery or the like can be applied.

[0021]

According to the output control device for an electric vehicle of the first to third aspects, since the first threshold temperature and the second threshold temperature are changed in consideration of the battery load, the battery temperature is simply high. Also, when the battery load is small, unnecessary output limitation of the motor is not performed, and the passenger does not feel uncomfortable deceleration. Further, when the battery load is large, such as when the vehicle travels rapidly at a high speed, the output of the motor can be limited before the upper limit temperature of the battery is reached, and an excessive temperature rise can be suppressed. Further, since the temperature change of the battery is extremely slow, it is not necessary to create a complicated control map or the like for controlling the output of the motor. Therefore, practical application of the output control device for an electric vehicle according to the first to third aspects can be expected.

According to the output control device of the electric vehicle of the fourth aspect, since the rate of change of the battery temperature is used instead of utilizing the partial cooling phenomenon by the blower, cooling is not performed due to a failure of the blower. Even in this case, the battery load can be determined. As a result, it is possible to prevent unnecessary output limitation of the motor and suppress an excessive rise in battery temperature.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 is a configuration diagram showing a first embodiment of an output control device for an electric vehicle according to the present invention.
Twelve battery modules 2 arranged in 6 rows are provided, and one battery module 2 is composed of eight cell batteries 1 made of a cylindrical lithium ion secondary battery. FIG. 1 illustrates only one row on one side of the 2 × 6 row battery module 2.

The battery case 10 is mounted, for example, on the floor between the wheel bases of an electric vehicle with the left side of FIG. 1 facing the front of the vehicle. An intake port 11 is opened, and the intake port 11 is opened toward the motor room via a duct (not shown).

On the other hand, an exhaust port 12 is opened at the rear of the battery case 10, and a blower 20 having a fan 21 driven to rotate by a fan motor 22 is attached to the exhaust port 12. Then, when the blower 20 is driven, cooling air is introduced from the motor room into the battery case 10 through the air inlet 11, and the cooling air is discharged from the exhaust port 12 while flowing through the gap between the battery modules 2. In this way, the battery case 10 houses the battery module 2 and constitutes a blower duct of the cooling device.

The battery cells 1 are all connected in series to form an assembled battery, and the voltage across the assembled battery is, for example, 300 to
It is 400V. Although not shown, the high-voltage power source using the assembled battery is connected to the propulsion motor 70 of the electric vehicle via the motor controller 60 such as an inverter, and the electric vehicle runs thereby.

As shown in FIG. 1, the voltage across the assembled battery is converted into a low voltage of 12 V by the DC / DC converter 4, which charges the auxiliary battery 5 and also serves as a drive source for the fan motor 22. The power source that has been turned to a low voltage by the DC / DC converter 4 is connected to, for example, a light, a wiper motor, a power steering pump, and other electrical components in addition to the auxiliary battery 5 and the fan motor 22, and is used as a drive source thereof. In FIG. 1, “3” is a cell controller provided in each battery module 2 and prevents over-discharging and over-charging in each battery module 2.

Each battery module 2 is provided with a battery temperature sensor 30 for detecting the battery temperature. The battery temperature sensor 30 is used as a general purpose, and its output signal is the blower controller 50 and the limiting threshold temperature changing means. It is connected so as to be input to 40.

The blower controller 50 takes in a signal from the battery temperature sensor 30 at a predetermined sampling time,
The output duty ratio of the blower 20 is controlled based on the battery temperature. The blower controller is configured by, for example, a microcomputer and an inverter to control the rotation speed of the fan motor 22, or by a microcomputer and a relay to control the operation / stop time ratio of the fan motor 22. Can be converted.

In the present embodiment, the battery temperature data of each battery module 2 from each battery temperature sensor 30 is sent to the limiting threshold temperature changing means 40, and the difference between the maximum battery temperature T _bmax and the minimum battery temperature T _bmin. The temperature DT is calculated. The limiting threshold temperature changing means 40 is composed of, for example, a microcomputer, and has the maximum battery temperature T _bmax and the minimum battery temperature T _{bm in.}
In addition to calculating the temperature difference DT with
Output limit start temperature (first threshold temperature) T _li of the motor 70 and maximum output limit temperature (second threshold temperature) T of the motor 70
_lf is determined based on the control maps shown in FIGS. 2 and 3.

FIG. 2 is a two-dimensional graph showing the control content of the limiting threshold temperature changing means 40, and FIG. 3 is a three-dimensional graph showing the same. As shown in FIG. 3, when the temperature difference DT between the battery modules 2 changes from 0 ° C. to 7 ° C., the maximum outputtable power of the motor shown on the vertical axis is
It is set by a three-dimensional matrix in the range of 10% to 100%. Here, the maximum outputtable power of the motor is set to a minimum value of 10%, which means an output that allows the electric vehicle to move. Specifically, it varies depending on the remaining capacity of the battery at that time. Although not shown, when the temperature difference DT exceeds 7 ° C, the control is the same as 7 ° C.

In the limiting threshold temperature changing means 40, for example, when the temperature difference DT between the battery modules 2 is as large as 7 ° C., that is, when the battery load is large, the maximum value T _bmax of the battery temperature of each battery module 2 is set. On the other hand, the output limit start temperature T _li of the motor and the maximum output limit temperature T of the motor are set so that the maximum _outputtable power of the motor becomes the curve shown in FIG.
_lf is set. In this case, as shown in FIGS. 2 and 3, the temperature range between the motor output limit start temperature T _li and the motor maximum output limit temperature T _lf is set to be relatively large (that is, a curve with a smooth fall). and then), it starts the motor output restriction at relatively low temperatures T _li, the maximum output restriction of the motor to a certain extent high temperature T _lf (10
%).

[0033] In contrast, the temperature difference DT is little between the battery module 2, if it is 0 ° C., that is, when the battery load is small, relative to the maximum value T _{bm ax} battery temperature of the battery modules 2 The maximum output power of the motor is shown in Fig. 2.
Motor output limit start temperature T
_li a motor output maximum temperature limit T _lf is set. In this case, as shown in FIGS. 2 and 3, the temperature range between the motor output limit start temperature T _li and the motor maximum output limit temperature T _lf is set to be relatively small (that is, a curve with a sharp fall). However, the output limitation of the motor is not started until the temperature becomes relatively high T _li . This is because the output limitation of the motor is not started early in response to the gradual temperature rise of the battery.

Next, the operation will be described. In this embodiment, 1
The battery temperature sensor 30 provided in each of the two battery modules 2 detects the battery temperature in each battery module 2 and sends it to the blower controller 50 and the limiting threshold temperature changing means 40. The battery temperature data is taken in at 1 second intervals, and an average value for 10 seconds is sampled at 1 minute intervals and used for control.

The blower controller 50 controls the output duty ratio of the blower 20 based on the battery temperature from the battery temperature sensor 30. When the battery load is large, the cooling capacity of the blower 20 is increased, while the battery load is small. In some cases, the cooling capacity is suppressed.

When the blower 20 is driven, a large amount of cooling air flows from the intake port 11 toward the exhaust port 12, but the air distribution is not uniform due to ventilation resistance and the like, and the larger the output of the blower 20 is. The flow rate near the blower 20 increases. Therefore, the battery module 2 arranged near the blower 20 has a relatively low temperature, and the blower 20
The temperature of the battery module 2 away from is relatively high. Therefore, in this case, the temperature difference DT between the battery modules 2 becomes large. On the other hand, when the battery load is small and the blower 20 is stopped or slightly driven, the amount of cooling air flowing from the intake port 11 to the exhaust port 12 is small, so that the battery module 2 The temperatures are almost equalized and the temperature difference DT is reduced. In the present embodiment, this partial cooling phenomenon is used for determining the battery load, which will be described later.

The battery temperature of each battery module 2 detected by the battery temperature sensor 30 is also sent to the limiting threshold temperature changing means 40, which is the highest among the input battery temperatures. Let the temperature be the maximum battery temperature T _bmax at that time, and the lowest temperature be the minimum battery temperature T _bmin at that time. And the maximum battery temperature T
temperature difference DT between _bmax and a minimum battery temperature T _bmin is calculated.
Further, based on the difference temperature DT which is the result of this calculation, the output limit start temperature T _li of the motor and the maximum output limit temperature T _lf of the motor are determined based on the control maps shown in FIGS. 2 and 3.

Further, when the control graph is determined by selecting the motor output limit start temperature T _li and the motor output maximum limit temperature T _lf , the limit threshold temperature changing means 40 determines the battery input from the battery temperature sensor 30. Of the temperatures, the maximum battery temperature T _bmax
The output limit signal of the motor 70 is sent to the motor controller 60 in accordance with the determined control graph. The motor controller 60 controls the motor 70 based on the output limit signal from the limit threshold temperature changing means 40.
Control the output of

For example, when traveling with a low load, the battery temperature rises little and the blower 20 is hardly driven. Therefore, the temperature difference DT between the battery modules 2 is 0.
Alternatively, the value becomes close to 0, and the control curve B shown in FIG. 2 is selected. As a result, even when the outside air temperature is high and the initial value of the battery temperature is also high, the temperature T _{lih at} which the output limitation of the motor 70 is started is relatively high as shown by B in FIG. Unnecessary output limitation of the motor 70 is avoided.

In addition, when traveling under high load
Indicates that the battery temperature rises significantly and the blower 20 rotates at full speed.
As a result, a temperature difference occurs between the battery modules 2 as shown in FIG.
Control curve B is selected. As a result, the output of the motor 70
Force limit T_lilAnd the maximum limit T _lflFunctions at relatively low temperatures
So even if the temperature rises suddenly,
Upper limit temperature T_lmaxCan be controlled not to exceed
You. The maximum temperature T of the battery module 2_bmaxIs a motor
70 output maximum limit temperature T_lfBefore reaching 3 ℃, the battery
More precise, switching the temperature sampling time every second
Control. However, the temperature data acquired one second ago
The latest capture data is calculated based on the average value for 10 seconds calculated in
The maximum battery temperature T_bmaxToss
You.

Further, when the vehicle is traveling at a medium level, the control curve of the three-dimensional matrix shown in FIG. 3 is selected according to the temperature difference DT between the battery modules 2 and the same control is performed. Further, in all cases, when the upper limit temperature of the battery is reached for some reason, the power distribution from the battery is immediately stopped to protect the battery, and then when the temperature falls below the output limit start temperature T _{li of the} motor 70, the _vehicle runs again. Return to a ready state. However, if the vehicle is stopped due to a failure of other equipment, it will not return to the runnable state.

As described above, according to the output control device of the electric vehicle of the present embodiment, even if the battery load is large and the cooling capacity of the blower 20 is insufficient, the output of the motor 70 is limited so that the battery temperature becomes excessive. Can be suppressed.

In particular, at this time, the battery load is judged by the temperature difference DT between the battery modules 2, and the output limit start temperature T _li of the motor 70 and the maximum output limit temperature T _{lf of the} motor are thereby determined.
Since the output of the motor 70 is limited after appropriately changing and, the output of the motor 70 is not limited when the output does not have to be limited, and the occupant does not feel uncomfortable deceleration. Moreover, since the output of the motor can be limited before the upper limit temperature T _lmax of the battery is reached, an excessive temperature rise can be suppressed. Since the temperature change of the battery is extremely slow, it is not necessary to create a complicated control map or the like for the output control of the motor 70 in the control of this embodiment.

Second Embodiment The output control device for an electric vehicle of the present invention can be modified in various ways. FIG. 4 is a graph showing three-dimensionally the control contents according to the second embodiment of the output control device for the electric vehicle of the present invention, and the device configuration is the same as that of the above-mentioned first embodiment, but the limit threshold temperature is changed. The method of determining the control curve in the means 40 is different.

That is, in the present embodiment, in determining the battery load, the rate of change (rate of increase) in battery temperature is used instead of the temperature difference DT between the battery modules 2. Then, in the limiting threshold temperature changing means 40, the maximum value _Tbmax of the battery temperatures detected by the battery temperature sensor 30 and the maximum value _Tbmax-1 taken one minute before the sampling time τ are obtained.
And the temperature change rate per unit time k = (T _bmax −T _{bmax −1} ) / τ are calculated.

Temperature change rate k obtained by this calculation
Is a limit control graph of the maximum outputtable power of the motor when it changes from 0 to 0.3 degrees / minute. As shown in FIG. 4, the maximum outputtable power of the motor is 10% to It is set by a three-dimensional matrix in the range of 100%. Here, the maximum outputtable power of the motor is set to a minimum value of 10%, which means an output that allows the electric vehicle to move. Specifically, it varies depending on the remaining capacity of the battery at that time. Although not shown, when the temperature change rate k exceeds 0.3 degrees / minute,
The control is the same as 0.3 degree / minute.

According to the limit control graph shown in FIG. 4, for example, when the rate of change k of the battery temperature is as large as 0.3 degrees / minute, that is, when the battery load is large, the maximum battery temperature of each battery module 2 is increased. With respect to the value T _bmax , the motor output limit start temperature T _li and the motor output maximum limit temperature T _lf are set so that the maximum _outputtable power of the motor becomes the curve shown in FIG. In this case, as shown in the same figure, the motor output limit start temperature T _li and the motor output maximum limit temperature T _lf
The temperature range between and is set to be relatively large (that is, a curve having a smooth fall), the output limitation of the motor is started at a relatively low temperature T _li , and the output limitation of the motor is limited to a high temperature T _lf. The maximum (10%) is not set.

On the other hand, when there is almost no change in battery temperature and k = 0, that is, when the battery load is small, the maximum value T _bmax of the battery temperature of each battery module 2 is set for the motor. The output limit start temperature T _li of the motor and the maximum output limit temperature T _{lf of the} motor are set so that the maximum _outputtable power becomes the curve shown in B of FIG. In this case, as shown in the figure, the temperature range between the motor output limit start temperature T _li and the motor output maximum limit temperature T _lf is set to be relatively small (that is, a sharp fall curve), The output limitation of the motor is not started until the temperature becomes relatively high _Tli . This is because the output limitation of the motor is not started early in response to the gradual temperature rise of the battery.

According to the output control device for an electric vehicle of this embodiment, the output of the motor 70 is limited even if the battery load is large and the cooling capacity of the blower 20 is insufficient, as in the first embodiment described above. Thus, it is possible to suppress an excessive rise in battery temperature.

In particular, at this time, the battery load is determined by the temperature change rate k of the battery module 2, and the output limit start temperature T _li of the motor 70 and the maximum output limit temperature T _lf of the motor 70 are thereby determined.
Since the output of the motor 70 is limited after appropriately changing and, the output of the motor 70 is not limited and the occupant does not feel uncomfortable when the output is not limited. . Moreover, since the output of the motor can be limited before the upper limit temperature T _lmax of the battery is reached, an excessive temperature rise can be suppressed. Since the temperature change of the battery is extremely slow, it is not necessary to create a complicated control map or the like for the output control of the motor 70 in the control of this embodiment.

Further, in the output control device for the electric vehicle of this embodiment, the rate of change k of the battery temperature is used instead of utilizing the partial cooling phenomenon by the blower 20.
The battery load can be determined even when 0 is not used and cooling is not performed.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, in the first embodiment, the temperature difference DT between the battery modules 2 is used as the criterion for determining the battery load, but the temperature variation of the battery modules 2 may be used as the criterion for determining the battery load.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of an output control device for an electric vehicle of the present invention.

FIG. 2 is a graph showing two-dimensionally the control contents in the limiting threshold temperature changing means according to the first embodiment.

FIG. 3 is a graph showing three-dimensionally the control contents in the limiting threshold temperature changing means according to the first embodiment.

FIG. 4 is a three-dimensional graph showing the control contents in the second embodiment of the output control device for the electric vehicle of the present invention.

FIG. 5 is a graph showing the control contents of a conventional electric vehicle output control device.

FIG. 6 is a graph for explaining the problems of the conventional example.

FIG. 7 is a graph for explaining the problems of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cell battery 2 ... Battery module 3 ... Cell controller 4 ... DC / DC converter 5 ... Auxiliary battery 10 ... Battery case 11 ... Intake port 12 ... Exhaust port 20 ... Blower 21 ... Fan 22 ... Fan motor 30 ... Battery temperature sensor 40 ... limit threshold temperature changing means 50 ... blower control means 60 ... motor controller 70 ... motor

Claims (4)

[Claims] 1. A motor that serves as a propulsion source for a vehicle, a plurality of battery modules that serve as a power source for the motor, a case that houses the plurality of battery modules, a blower that blows cooling air to the case, and Output control of an electric vehicle that is mounted on an electric vehicle having a plurality of battery temperature sensors that detect the battery temperature of a battery module and that controls the output of the motor based on each battery temperature detected by the plurality of battery temperature sensors In the device, a first threshold temperature at which the output of the motor is started, and a second threshold temperature at which the output of the motor is started to be kept at a minimum,
An output control device for an electric vehicle, comprising limit threshold temperature changing means for changing the temperature according to each battery temperature. 2. The limiting threshold temperature changing means changes the first threshold temperature and the second threshold temperature based on a temperature difference between the maximum battery temperature and the minimum battery temperature of the plurality of battery modules. The output control device for an electric vehicle according to claim 1, wherein 3. The limiting threshold temperature changing means changes the first threshold temperature and the second threshold temperature based on variations in battery temperatures of the plurality of battery modules. Item 1. An output control device for an electric vehicle according to item 1. 4. The limiting threshold temperature changing means changes the first threshold temperature and the second threshold temperature based on a temperature change rate of battery temperatures of the plurality of battery modules. The output control device for an electric vehicle according to claim 1.