JP2001130268A - Forced cooling device of battery for electric car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forced cooling device of a battery for an electric car to suppress the high-temperature degradation of the battery with small power consumption while suppressing complicate configuration. SOLUTION: In a battery cooling fan 3 to feed the outside air to be cooled to the battery 1 and cool it, the operation of the battery cooling fan 3 is stopped when the temperature of the battery 1 reaches or falls below the preset temperature (also, referred to as the target value) for stopping the cooling, and the operation of the battery cooling fan 3 is also stopped when the temperature of the battery reaches or falls below the predetermined offset temperature ΔT added to the temperature of the cooling air. In this configuration, heat generation from the battery 1 is small in a condition where the temperature of the cooling air exceeds the target temperature such as under the burning sun, and wasteful power consumption of the fan can be saved if the cooling air contributes less to the battery cooling in a condition where the temperature of the battery reaches or falls below the predetermined offset temperature ΔT added to the temperature of the cooling air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for forcibly cooling a battery for an electric vehicle.

[0002]

2. Description of the Related Art An assembled battery for driving an electric vehicle (hereinafter also referred to as a battery) has a structure in which several tens of battery modules of several volts to several tens of volts are connected in series, and these are assembled into one package. For example, it is mounted under the floor of the passenger compartment.

The performance and life of a battery greatly depend on the temperature environment. Particularly, when the battery is charged and discharged at a high temperature (for example, 40 ° C. or more), the deterioration is remarkable. Therefore, it is known that a traveling wind is introduced into a cooling air flow path around the battery. Have been.

Further, when sufficient traveling wind is not obtained (for example, when the battery is charged from the outside), the outside air is forcibly blown into the cooling air passage by a fan,
Furthermore, a cooling device for air cooling (commonly known as
It has been considered to provide an evaporator for an air conditioner and blow the cold air to a battery.

[0005] The use of such a fan or air conditioner consumes the stored power of the battery.
This battery temperature is set to a preset target temperature (for example, 3
Power consumption is reduced by performing fan operation control for operating the fan in a range exceeding about (0 ° C.).

When the battery temperature reaches a predetermined value,
It is also known to forcibly cut off the charge / discharge current of a battery to protect the battery and ensure safety.

[0007]

However, in the above-described conventional forced air blowing system, when the outside air temperature exceeds the target temperature, such as in hot summer weather, the fan operates continuously regardless of the battery heat generation condition. However, naturally, the battery temperature does not fall below the outside air temperature and below the target temperature, and when the heat generation of the battery is small, the effect of the forced air blowing is hardly exerted, and the efficiency of the stored power in the electric vehicle is small. Because use is extremely important,
On the contrary, the disadvantage of increasing the power consumption of the fan increases.

[0008] It is effective to add a cooling device for air cooling (commonly called an air conditioner) and provide an evaporator in a ventilation path for battery cooling to cool the battery cooling air, which is effective for battery cooling. Practical use has been difficult in view of the increase in size, cost, and power consumption. In the power consumption of the air conditioner, the power of the compressor of the air conditioner is much larger than that of the fan, and further, the fan power for cooling the condenser of the air conditioner is required.

Shutting down or limiting the battery charge / discharge current to protect the battery and ensure safety when the battery temperature rises causes a great decline in the performance of an electric vehicle using the stored power of the battery as running energy, and is avoided as much as possible. Needless to say, it is necessary.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a forced cooling device for an electric vehicle battery that suppresses high-temperature deterioration of a battery with low power consumption while suppressing complication of the configuration. That is the purpose.

[0011]

According to the forcible cooling device for an electric vehicle battery of the present invention, the battery cooling fan for blowing the outside air cooling air to the battery to cool the battery has a predetermined battery temperature. When the operation of the battery cooling fan is stopped when the temperature becomes equal to or lower than the cooling stop set temperature value (also referred to as a target temperature), and when the battery temperature becomes equal to or lower than a value obtained by adding a predetermined offset temperature ΔT to the temperature of the cooling air. The operation of the battery cooling fan is also stopped.

With this arrangement, in a situation where the temperature of the cooling air exceeds the target temperature, such as in hot summer weather, the heat generation of the battery is small, and the battery temperature is a value obtained by adding the predetermined offset temperature ΔT to the temperature of the cooling air. Under the following circumstances, wasteful fan power consumption when the cooling air does not contribute much to battery cooling can be saved, and further, battery heat generation due to this power consumption can be reduced.

In the present invention, the electric vehicle includes a type in which running energy is purely provided only by a secondary battery, and a type in which a part or all of the electric vehicle is provided by an internal combustion engine or a fuel cell. The offset temperature ΔT is usually set to several degrees Celsius or less in consideration of the temperature difference due to the thermal resistance between the battery and the cooling air. However, the offset temperature ΔT can be set to almost zero.

According to a second aspect of the present invention, in the forced cooling device for an electric vehicle battery according to the first aspect,
The cooling air temperature sensor is an outside air temperature sensor that detects an outside air temperature.

In other words, the forced cooling device of the present configuration employs an external air fan which consumes less power and can reduce the device configuration and weight as a battery cooling fan. In this configuration, the battery cooling air is kept at the external air temperature or lower. Therefore, the situation that the temperature of the battery cooling air exceeds the target temperature is likely to occur, and the fan power saving effect by stopping the fan in this situation is great.

According to a third aspect of the present invention, in the forced cooling device for an electric vehicle battery according to the first aspect,
The controller adjusts the air volume of the battery cooling fan so that the difference between the cooling air temperature and the battery temperature and the difference between the battery temperature and the cooling stop set temperature value have a positive correlation with each other. It is possible to finely reduce the fan power consumption while suppressing.

According to a fourth aspect of the present invention, in the forced cooling device for an electric vehicle battery according to the first aspect,
When the battery temperature exceeds a predetermined threshold temperature, the airflow (cold air) for the vehicle interior air conditioning of the vehicle interior air conditioning is branched to the battery as the cooling air, so it is necessary to newly install a battery cooling air conditioner. As a result, the battery cooling effect can be further improved while avoiding an increase in vehicle size, weight and cost.

According to a fifth aspect of the present invention, in the forced cooling device for an electric vehicle battery according to the fourth aspect,
If the battery temperature is equal to or lower than a predetermined threshold, the battery is cooled by a forced air blowing method using a battery cooling fan,
If the battery temperature exceeds the predetermined threshold value, the vehicle compartment air-conditioning air flow branching means and the vehicle compartment air-conditioning device are operated to introduce the vehicle compartment air-conditioning airflow into the air passage of the battery cooling fan to cool the battery. .

In this way, the battery can normally be cooled with the power consumption of only the battery cooling fan,
When the temperature of the battery rises abnormally or when the outside air temperature is extremely high, the battery can be cooled by the cold air of the vehicle interior air conditioner, so that the battery protection is improved,
In addition, the battery operation can be performed in a severe temperature environment without adopting the charge / discharge current interruption or reduction of the battery, and the vehicle operation performance can be improved.

According to the sixth aspect of the present invention, when the battery temperature exceeds a predetermined threshold temperature, the cool air formed by the air conditioner with the refrigerator for air conditioning in the vehicle compartment is branched to the battery, so that the battery is simple. With the configuration, battery operation can be realized even at high temperatures while battery deterioration is suppressed.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to examples.

[0022]

Embodiment 1 (Configuration) FIG. 2 shows a layout of the battery for an electric vehicle.

Reference numeral 1 denotes a running battery, which is divided into a large number (three in FIG. 1) of battery blocks 10 electrically connected in series in this embodiment.
It consists of a number of cells connected in series. Running battery 1
Is mounted in a battery compartment s below the floor of the cabin of the electric vehicle. The front end of the battery chamber s is opened to be an outside air intake s1, and the rear end is opened to be an exhaust port s2. The traveling battery 1 supplies power to the traveling motor through a traveling inverter (not shown), and is charged from an external charging means through a charging connector (not shown).

Reference numeral 2 denotes a plurality of battery temperature detection sensors disposed close to or incorporated in the traveling battery 1. Each battery temperature sensor 2 measures the temperature of each battery block 10 of the traveling battery 1.

Reference numeral 3 denotes a battery cooling fan that forcibly cools the traveling battery 1 and is disposed between the outside air intake s1 and the traveling battery 1 in the battery chamber s. By driving the battery cooling fan 3, the outside air introduced into the battery pack from the outside air intake s 1 is used as cool air, and is forcibly blown to the cooling space s 2 to drive the running battery 1.
To cool down.

Reference numeral 4 denotes an outside air temperature sensor which is arranged near the outside air intake s1 and measures the outside air temperature.

A controller 5 controls the operation of the battery cooling fan 3 based on the temperatures obtained from the battery temperature sensor 2 and the outside air temperature sensor 4. (Operation) Next, the drive control of the battery cooling fan 3 by the controller 5 will be described with reference to the flowchart shown in FIG.

First, the connection of the charging connector is confirmed (S
1) If the connection is interrupted, the charging is stopped (S2) and the battery cooling fan 3 is stopped (S3), and all the systems are terminated.

If the charging connector is connected, data from each battery temperature sensor 2 is calculated to determine the battery temperature (S4). This calculation is, for example, a calculation for calculating an average value or a calculation for extracting a maximum value.

Next, the outside air temperature T is read from the outside air temperature sensor 4 (S5), the total current IB of the running battery 1 is read from a current sensor (not shown), and the terminal voltage is detected from each unit cell or each battery block. (S6).

Next, the charge amount of the traveling battery 1 is calculated from these data (S7) to determine whether or not the battery is fully charged (S8). If the battery is fully charged, the charging is stopped at S11 and S13. Proceed to.

If the battery is not fully charged, it is checked whether the battery temperature TB is higher than a preset upper limit temperature KTlimit. If it is higher, the charging is stopped (S11). If not, the charging is started or continued. (S10), proceed to S12.

In steps S12 and S13, a cooling target temperature (target temperature) Tref of the battery 1 is set. Since the rise in the temperature of the traveling battery 1 is suppressed after charging is completed as compared to during charging, in this embodiment, the cooling target temperature Tref is separately set during charging and after charging, so that the battery temperature TB becomes higher. To reach the target temperature early,
The operation of the battery cooling fan 3 is stopped early. That is, the cooling target temperature Tref is KT when charging is continued.
1 is set to KT2 when charging is completed. However, KT1 is a lower value than KT2.

Next, the set cooling target temperature Tref is compared with the outside air temperature T (S14). If the outside air temperature T is lower than the cooling target temperature Tref, the stop temperature Tstop is set to the cooling target temperature Tref (S16). If the outside air temperature T is equal to or higher than the cooling target temperature Tref, the cooling stop temperature Tstop
Is set to the outside air temperature T + ΔT. ΔT is the offset temperature, the temperature of the battery 1 for running is slightly increased, the temperature of the battery cooling fan 3 is stopped, and the temperature is substantially equal to the temperature detected by the battery temperature sensor 2, for example, 0 or less than several degrees Celsius.
Preferably, it is set to about 1 ° C.

Next, the cooling stop temperature Tst set here is set.
op is compared with the battery temperature TB (S17). If the battery temperature TB is higher than the cooling stop temperature Tstop, the battery cooling fan 3 is operated or the operation is continued (S18). If the battery temperature TB becomes lower than the cooling stop temperature Tstop, the battery is turned off. The cooling fan 3 is stopped (S19).

Thus, the outside air temperature T becomes equal to the cooling target temperature T.
If the temperature is higher than ref, the battery temperature TB cannot be lowered to the cooling target temperature Tref or less, and thus the operation of the battery cooling fan 3 cannot be stopped, and wasteful power consumption with a poor cooling effect has been continued (see FIG. 3), in this embodiment, the battery temperature TB is lower than the outside air temperature T +.
Since the battery cooling fan 3 can be stopped at the time when ΔT has been reached, wasteful power consumption can be suppressed (see FIG. 4).

As in the conventional case, when the cooling target temperature Tref is higher than the outside air temperature T, the battery temperature TB
When the temperature reaches the cooling target temperature Tref, the battery cooling fan 3 is stopped to reduce power consumption (see FIG. 5).

Further, in this embodiment, after the battery cooling fan 3 is stopped (S19), it is determined that charging is completed (S2).
0) During the charging, the drive control routine of the battery cooling fan 3 of FIG. 2 is executed.

(Modification) In the above embodiment, as shown in FIG. 2, the cooling stop temperature T is switched to one of the outside air temperature T + the offset temperature ΔT and the cooling target temperature Tref.
Although the stop and the battery temperature were compared, the outside air temperature T +
The offset temperature ΔT is compared with the battery temperature TB, the cooling target temperature Tref is compared with the battery temperature TB, and in either case, the battery cooling fan 3 may be operated only when the battery temperature TB is high. Is obvious.

(Modification) In the above embodiment, as shown in FIG. 2, the battery cooling fan 3 during vehicle stop charging is used.
Is described, but it is needless to say that the control at the time of discharging or charging (hybrid vehicle) of the traveling battery 1 during the operation of the vehicle can be similarly performed.

[0041]

Embodiment 2 Another embodiment of the present invention will be described with reference to the layout diagram shown in FIG. 6 and the flowchart shown in FIG.

The arrangement shown in FIG. 6 is different from the arrangement of the first embodiment shown in FIG. 1 in that the cool air of the vehicle air conditioner 6 can be taken into the battery compartment s.

The cabin air conditioner 6 comprises a cabin air conditioning duct 6
1. An evaporator 62 provided in the cabin air-conditioning duct 61, a compressor 63, a fan-equipped condenser 64, an expansion valve 65, and a refrigerant that circulate the refrigerant together with the evaporator 62 to form a cabin air-conditioning refrigeration cycle. A refrigerant pipe 66 is provided. Further, the cabin air conditioner 6 has a branch duct 66 branched from the cabin air conditioning duct 61 and connected to the entrance of the battery compartment S, and branch dampers 67 and 68 installed at the entrance and exit of the branch duct 66. ing. The branch damper 67 is an opening / closing damper or a proportional control damper for switching the cool air cooled by the evaporator 62 to either the vehicle room or the battery room S. Similarly, the branch damper 68 is configured to use the cool air from the evaporator 62 and the outside air. And an open / close damper or a proportional control damper for introducing the battery chamber S by switching either of them. Although two dampers are used in this embodiment, the branch damper 67 may be omitted.

The cabin air conditioner 6 is a conventional cabin air conditioner
The air conditioning is performed in the manual control mode or the automatic control mode. (Operation) Next, the branch damper 6 by the controller 5
7, 68 and the control of the vehicle interior air conditioner 6 will be described with reference to the flowchart shown in FIG.

The control of this embodiment is similar to the control of the first embodiment shown in FIG. 2, except that a step S2 is performed between S17 and S18 to compare the battery temperature TB with a predetermined threshold temperature Tth.
1 and control steps S22 and S23 of the branch dampers 67 and 68 and the vehicle interior air conditioner 6 based on the comparison result, and a control step S24 of the rotation speed of the battery cooling fan 3 are added.

However, in step 5 (S5), the outside air temperature sensor 4 accurately detects the air temperature (also referred to as cooling air temperature) T before the battery cooling fan 3, and proceeds to step 1
4 (S14), the air temperature (cooling air temperature) T is compared with the cooling stop temperature Tstop, and the process proceeds to step S15.
In (S15), the cooling stop temperature Tstop is set to this air temperature (cooling air temperature) T + ΔT.

At S21, as described above, the battery temperature T
B is compared with a predetermined threshold temperature Tth. If the battery temperature TB is higher than the threshold temperature Tth, the process proceeds to S22; otherwise, the process proceeds to S23. In this embodiment, the predetermined threshold temperature Tth is lower than the upper limit temperature KTlimit for prohibiting charging, but is set to be considerably higher than the cooling target temperature Tref. For example, in this embodiment, the predetermined threshold temperature Tth is equal to the upper limit temperature KTli.
5 ° C. lower than mit.

In step S22, it is determined that the battery temperature TB is high and the battery temperature TB should be strongly reduced. The branch damper 68 is controlled to the open side and the branch damper 68 is controlled to the outside air cutoff side. Thereby, the cooling air of the vehicle interior air conditioner 6 is introduced into the battery compartment S, and the traveling battery 1 is cooled strongly.

In S23, it is determined that the battery temperature TB is low, and that the strong cooling by the cabin air conditioner 6 is not necessary, the shutoff of the cabin air conditioner 6 is instructed, and the branch damper 67 is controlled to the branch duct 66 closing side. The branch damper 68 is controlled to the outside air introduction side. Thereby, outside air is introduced into the battery chamber S,
The running battery 1 is economically cooled.

At S24, the air temperature T (also referred to as cooling air temperature) T before the battery cooling fan 3 and the battery temperature TB
The airflow of the battery cooling fan 3 is determined based on a map of the temperature and the cooling stop temperature Tstop. It is assumed that the battery cooling fan 3 has a variable air volume, that is, a variable number of revolutions, by inverter control.

In this map, as the battery temperature TB becomes higher than the cooling air temperature T, the battery cooling fan 3
It is assumed that the airflow of the battery cooling fan 3 is further increased as the battery temperature TB becomes higher than the cooling stop temperature Tstop. In this way, it is possible to save the power consumption of the battery cooling fan 3 while suppressing a decrease in the temperature of the traveling battery 1.

(Modification) The branch dampers 67 and 68 may be constituted by one multi-branch damper. Also, the branch damper 6
7 is a proportional control damper, so that the cabin air conditioner 6
, Air conditioning and battery cooling can be performed simultaneously.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a forced cooling device for an electric vehicle battery according to the present invention.

FIG. 2 is a flowchart illustrating a control example of a controller illustrated in FIG. 1;

FIG. 3 is a timing chart showing a transition of a battery temperature TB in the conventional battery cooling fan control.

FIG. 4 is a timing chart (when the outside air temperature is high) showing a transition of a battery temperature TB in the battery cooling fan control of FIG. 2;

FIG. 5 is a timing chart (when the outside air temperature is low) showing a transition of a battery temperature TB in the battery cooling fan control of FIG. 2;

FIG. 6 is a block diagram showing another embodiment of the forced cooling device for an electric vehicle battery according to the present invention.

FIG. 7 is a flowchart illustrating a control example of the controller illustrated in FIG. 6;

[Description of Signs] 1 is a running battery 1, 2 is a battery temperature sensor, 3 is a battery cooling fan, 4 is an outside air temperature sensor (cooling air temperature sensor), 5 is a controller, 6 is a vehicle cabin air conditioner, 6
Reference numerals 7 and 68 denote branch ducts (air flow branching means for cabin air conditioning).

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3D035 AA03 3D038 AA09 AB01 AC00 AC04 AC22 3H021 AA01 BA04 BA11 BA12 BA20 CA06 CA09 DA01 DA02 DA12 EA07 5H115 PA08 PA11 PG04 PI16 PO07 PO14 TI10 TO05 TR19 TU12 UI29 UI35 UI35

Claims (6)

[Claims] 1. A battery cooling fan that blows air to a battery for an electric vehicle to cool the battery, a battery temperature sensor that detects a temperature of the battery, and a battery temperature that is equal to or lower than a predetermined cooling stop set temperature value. A controller for stopping the operation of the battery cooling fan when the battery cooling fan is turned off, comprising: a cooling air temperature sensor for detecting a temperature of cooling air introduced into the battery by the battery cooling fan. An electric vehicle, wherein the controller stops the operation of the battery cooling fan when the battery temperature becomes equal to or less than a value obtained by adding a predetermined offset temperature ΔT to the temperature of the cooling air. Battery forced cooling device. 2. The forced cooling device for an electric vehicle battery according to claim 1, wherein the cooling air temperature sensor is an outside air temperature sensor that detects an outside air temperature. . 3. The forced cooling device for an electric vehicle battery according to claim 1, wherein the controller adjusts the flow rate of the battery cooling fan with a positive correlation with a difference between the cooling air temperature and the battery temperature. A forced cooling device for the battery of the electric vehicle, wherein the airflow of the battery cooling fan is adjusted with a positive correlation between a difference between the battery temperature and the set temperature value for cooling stop. 4. The forced cooling device for a battery of an electric vehicle according to claim 1, wherein an airflow for air conditioning of a vehicle room sent by a vehicle air conditioner for air-conditioning a vehicle room of the electric vehicle is used as the cooling air as the cooling air. A controller for instructing the cabin air-conditioning air flow branching unit when the battery temperature exceeds a predetermined threshold temperature, wherein A forced cooling device for an electric vehicle battery, wherein an air flow is branched to the battery. 5. The forced cooling device for an electric vehicle battery according to claim 4, wherein the controller is configured to control the battery cooling fan only when the battery temperature exceeds the predetermined threshold value despite the operation of the battery cooling fan. A forced cooling device for a battery of an electric vehicle, wherein the compartment air-conditioning air flow branching means and the compartment air-conditioning device are operated to introduce the compartment air-conditioning air flow into a ventilation path of the battery cooling fan. . 6. A forced cooling device for an electric vehicle battery that blows air to a battery for an electric vehicle to cool the battery, comprising: a battery temperature sensor for detecting a temperature of the battery; A vehicle air-conditioning air flow branching unit that branches the vehicle air-conditioning air flow sent by the vehicle room air-conditioning device to the battery side as cooling air, and the vehicle room air-conditioning when the battery temperature exceeds a predetermined threshold temperature. A controller for instructing the airflow branching means to branch the airflow for cabin air conditioning to the battery.