JP6358425B2 - In-vehicle battery temperature control device - Google Patents

Description

  The present invention relates to a temperature control device that controls temperature by circulating a heat medium in a battery mounted on a vehicle.

Some vehicles equipped with a high-capacity, high-power battery such as an electric vehicle or a hybrid vehicle are equipped with a battery temperature control device for controlling the temperature of the battery. As the battery temperature control device, for example, a cooling device such as an air cooling type or a liquid cooling type (water cooling type) that cools the battery using a heat medium such as cooling water has been developed.
Further, Patent Document 1 discloses a heat exchange state in which a heat medium is circulated through a battery pack (battery stack) in which a battery is mounted therein and the battery can be cooled, and a heat insulation state in which the heat medium is discharged from the battery pack. A cooling device having a switchable configuration has been proposed. In this cooling device, for example, when the vehicle is left in a cold state and the battery temperature is low, the heat medium is discharged from the battery pack to reduce the heat capacity of the battery, and the battery temperature is reduced by self-heating of the battery. Immediately raise to improve battery performance.

Japanese Patent No. 4131110

However, in Patent Document 1, the timing for discharging the heat medium is limited at the start, and when the battery is cooled by circulating the heat medium, the cooling performance varies depending on the surrounding environment. Under the circumstances, it is desired to further improve the battery performance by maintaining the temperature of the battery at an appropriate temperature or making it closer to the appropriate temperature more quickly.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicle-mounted battery that appropriately switches between a heat exchange state and a heat-retaining state under various circumstances, thereby making the battery suitable temperature. It is to provide a temperature control apparatus.

In order to achieve the above object, a temperature control device for an on-vehicle battery according to claim 1 includes a heat medium path that allows a heat medium to pass around a battery mounted on the vehicle, a heat medium that passes through the heat medium path, and outside air. A vehicle-mounted battery temperature control device comprising a heat exchanger for exchanging heat between the heat medium path and the heat exchanger to circulate the heat medium between the outside air and the battery via the heat medium. A heat exchanging state for exchanging heat, a switching device that switches the heat medium from the heat medium path to a heat retaining state that suppresses heat exchange between the outside air via the heat medium and the battery, and the temperature of the battery A control device configured to control the operation of the switching device on the basis of an outside air temperature and set the switching between the heat exchange state and the heat retaining state, and the control device has a temperature of the battery at the outside air temperature. Switching when the threshold is greater than the threshold set based on And the battery is a power supply source at the start of the vehicle, and the threshold is set when the temperature of the battery is lower than the threshold. Is set higher as the outside air temperature is lowered, and is set lower than when the vehicle is stopped when the vehicle is started .

Also, temperature control device of a vehicle-mounted battery according to claim 2, in claim 1, during traveling of the vehicle, the threshold value regardless of the outside air temperature is characterized in that it is set to a constant value.

According to a third aspect of the present invention, there is provided the temperature control device for an in-vehicle battery according to the first or second aspect , wherein the control device is in the warm state when the outside air temperature is higher than an appropriate temperature range set according to the characteristics of the battery. It is characterized by setting.

  According to the temperature control device for the on-vehicle battery according to claim 1, the temperature control device is switched between the heat exchange state and the heat insulation state based on the battery temperature and the outside air temperature. Accordingly, it is possible to switch between the heat exchange state and the heat retention state at an appropriate timing using the temperature control effect of different batteries. As a result, the battery temperature can be set to an appropriate temperature under various circumstances, and the battery performance can be improved.

Batteries temperature is set to the heat exchanger state when it is set threshold or more on the basis of the outside air temperature, together with the set warmth state when the battery temperature is less than the threshold value, the outside air temperature decreases Accordingly, the threshold value is set high, so that the battery temperature becomes lower as the outside air temperature rises as switching between the heat exchange state and the heat retaining state is performed at a higher battery temperature as the outside air temperature falls. The temperature is switched between the heat exchange state and the heat insulation state. Therefore, when the outside air temperature is low, excessive cooling can be suppressed and the battery temperature can be maintained at an appropriate temperature. When the outside air temperature is high, the battery temperature can be increased if the battery temperature is low. The temperature can be quickly brought close to the appropriate temperature.

Further, since the threshold is set lower at the time of starting than at the time of stopping, switching between the heat exchange state and the heat retaining state is performed at the battery temperature at the time of starting lower than that at the time of stopping. Therefore, switching between the heat exchange state and the heat retaining state is performed in consideration of the fact that the battery temperature rises due to self-heating due to the use of electric power at the time of starting, and appropriate switching can be performed at each time of starting and stopping. .

According to the temperature control device of a vehicle-mounted battery according to claim 2, in traveling, because the outside air temperature and the battery temperature becomes substantially constant relationship accurately switching determination of the insulation state and heat exchange state only the battery temperature And can be done easily.
According to the temperature control device for an in-vehicle battery according to claim 3 , when the outside air temperature is higher than the appropriate temperature range of the battery, the heat exchange between the outside air and the battery is suppressed by keeping the temperature, so that the appropriate battery Temperature rise exceeding the temperature range can be suppressed.

It is a block diagram of the temperature control apparatus of the vehicle-mounted battery which concerns on one Embodiment of this invention. In the temperature control apparatus of the vehicle-mounted battery of this embodiment, it is explanatory drawing which shows the position of the cooling water in a heat exchange state. In the temperature control apparatus of the vehicle-mounted battery of this embodiment, it is explanatory drawing which shows the position of the cooling water in a heat retention state. It is a flowchart which shows the operating point of each valve | bulb and water pump at the time of switching from a heat exchange state to a heat retention state. It is a flowchart which shows the operating point of each valve | bulb and water pump at the time of switching from a heat retention state to a heat exchange state. It is an example of the map for switching determination of a heat exchange state and a heat retention state.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a temperature control device for an in-vehicle battery according to an embodiment of the present invention.
The in-vehicle battery temperature control device 1 of the present embodiment is applied to a vehicle equipped with an in-vehicle battery that outputs electric power to a travel drive motor, such as an electric vehicle or a plug-in hybrid vehicle.
In the present embodiment, the battery pack 2 is mounted on the vehicle as an in-vehicle battery.

  As shown in FIG. 1, the battery pack 2 is configured by mounting a plurality of batteries 4 in a case 3. Inside the battery pack 2, an internal cooling water passage 5 (heat medium passage) that is a passage of cooling water (heat medium) is formed around each battery 4. The internal cooling water channel 5 is supplied with cooling water from an inflow port 6 provided at the upper part of the battery pack 2, and from a discharge port 7 provided at the lower part of the battery pack 2, specifically at the lowest position of the internal cooling water channel 5. The cooling water can be discharged, and heat can be exchanged between the cooling water flowing through the internal cooling water channel 5 and the battery 4.

In the battery pack 2, a lower cooling water tank 8, which is a space in which cooling water can be stored, is provided below the battery 4. The lower cooling water tank 8 is capable of inflowing and discharging cooling water from a lower tank outflow inlet 9 provided at the lowest position. The upper part of the lower cooling water tank 8 communicates with the upper part of the internal cooling water channel 5 via the upper communication path 10.
The inlet 6 and the outlet 7 are communicated with each other by an external cooling water passage 15 provided outside the battery pack 2, and a heat exchanger 16 is interposed in the external cooling water passage 15. The heat exchanger 16 has a function of exchanging heat between the cooling water passing through the external cooling water passage 15 and the outside air.

The external cooling water passage 15 between the discharge port 7 and the heat exchanger 16 and the lower tank outflow inlet 9 communicate with each other via the lower communication passage 17.
In the external cooling water passage 15, a water pump 20 (WP) is provided between the connection portion 18 with the lower communication passage 17 and the heat exchanger 16. The water pump 20 has a function of discharging the cooling water in the external cooling water passage 15 from the discharge port 7 side toward the inflow port 6 side.

Between the heat exchanger 16 and the inlet 6 of the external cooling water channel 15, a first opening / closing valve 21 (V 1) that opens and closes the external cooling water channel 15 is provided. A second opening / closing valve 22 (V2) for opening and closing the external cooling water passage 15 is provided between the discharge port 7 of the external cooling water passage 15 and the connecting portion 18.
The lower communication path 17 is provided with a third opening / closing valve 23 (V3) for opening and closing the lower communication path 17.

A connecting portion between the upper communication passage 10 and the lower cooling water tank 8 is provided with a fourth opening / closing valve 24 (V4) for opening and closing the upper communication passage 10.
The water pump 20, the first on-off valve 21, the second on-off valve 22, the third on-off valve 23, and the fourth on-off valve 24 correspond to the switching device of the present invention.
The battery pack 2 is provided with a battery temperature sensor 30 that detects the temperature of the battery 4.
The vehicle is also provided with an outside air temperature sensor 31 that detects the outside air temperature.

The water pump 20, the first on-off valve 21, the second on-off valve 22, the third on-off valve 23, and the fourth on-off valve 24 are controlled by a control unit 40 (control device).
The control unit 40 includes an input / output device, a storage device (ROM, RAM, nonvolatile RAM, etc.), a central processing unit (CPU), a timer, and the like. From the vehicle control unit (not shown), the vehicle state (running, At the time of stoppage and start-up), and the battery temperature and the outside air temperature are inputted from the battery temperature sensor 30 and the outside air temperature sensor 31, and the water pump 20, the first opening / closing valve 21, the second opening / closing valve 22, and the third opening / closing. Operation control of the valve 23 and the fourth open / close valve 24 is performed.

In this embodiment, the water pump 20 and the valves 21 to 24 are operated and controlled, the cooling water in the temperature control device 1 is moved, and the internal cooling water passage 5 and the external cooling water passage 15 are filled with the cooling water and circulated. It is possible to switch between an exchange state and a heat retention state in which cooling water is discharged from the internal cooling water channel 5 to the lower cooling water tank 8.
FIG. 2 is an explanatory diagram showing the position of the cooling water in the heat exchange state. FIG. 3 is an explanatory diagram showing the position of the cooling water in the heat retaining state. In FIGS. 2 and 3, the horizontal hatching indicates the position of the cooling water.

In the heat exchange state, the first on-off valve 21 and the second on-off valve 22 are opened, and the third on-off valve 23 and the fourth on-off valve 24 are closed.
Then, as shown in FIG. 2, the internal cooling water channel 5 and the external cooling water channel 15 are filled with cooling water, and by operating the water pump 20 in this state, as shown by the arrows in FIG. Cooling water circulates through the cooling water channel 5 and the external cooling water channel 15. At this time, when the battery 4 is in a high temperature state, the battery 4 is cooled by exchanging heat with the battery 4 by the cooling water passing through the internal cooling water channel 5, and the high temperature cooling water is cooled by the heat exchanger 16. Return to the internal cooling water channel 5.

In the heat retaining state, the third opening / closing valve 23 is opened, and the first opening / closing valve 21, the second opening / closing valve 22, and the fourth opening / closing valve 24 are closed.
As shown in FIG. 3, the heat retaining state is a state in which the cooling water is discharged from the internal cooling water channel 5 and flows into the lower cooling water tank 8.
FIG. 4 is a flowchart showing the operating procedure of the valves 21 to 24 and the water pump 20 when switching from the heat exchange state to the heat insulation state.

This control is executed when it is determined to switch from the heat exchange state as shown in FIG. 2 to the heat insulation state as shown in FIG.
First, in step S10, the operation of the water pump 20 is stopped. Then, the process proceeds to step S20.
In step S20, the third on-off valve 23 and the fourth on-off valve 24 are opened. Since the first on-off valve 21 and the second on-off valve 22 are opened in the heat exchange state, they are left in the open state. Thereby, the cooling water in the internal cooling water channel 5 flows into the lower cooling water tank 8 through the lower communication passage 17. Then, the process proceeds to step S30.

  In step S30, the process waits until the cooling water has been moved to the lower cooling water tank 8. Specifically, in step S20, the process waits until a predetermined time elapses after the third opening / closing valve 23 and the fourth opening / closing valve 24 are opened. The predetermined time may be set to be longer than the time required for the cooling water to move from the internal cooling water channel 5 to the lower cooling water tank 8. At this time, the upper communication passage 10 functions as an air vent passage. Then, the process proceeds to step S40.

In step S40, the first opening / closing valve 21, the second opening / closing valve 22, and the fourth opening / closing valve 24 are closed. Then, this routine ends.
FIG. 5 is a flowchart showing the operating procedure of the valves 21 to 24 and the water pump 20 when switching from the heat retention state as shown in FIG. 3 to the heat exchange state as shown in FIG.
This control is executed when it is determined to switch from the heat retaining state to the heat exchange state by switching determination control described later.

First, in step S100, the second opening / closing valve 22 is closed. Although the second opening / closing valve 22 is closed in the heat retaining state, the valve closing operation is performed in this step in order to ensure the valve closing state. Then, the process proceeds to step S110.
In step S110, the first on-off valve 21, the third on-off valve 23, and the fourth on-off valve 24 are opened. Then, the process proceeds to step S120.

In step S120, the water pump 20 is operated. Thereby, the cooling water in the lower cooling water tank 8 flows into the internal cooling water channel 5 from the inlet 6 through the lower communication passage 17. Then, the process proceeds to step S130.
In step S130, the process waits until the cooling water has been moved to the internal cooling water channel 5. Specifically, in step S120, the operation waits until a predetermined time elapses after the water pump 20 starts operating. The predetermined time may be set to be equal to or longer than the time required to complete the movement of the cooling water from the lower cooling water tank 8 to the internal cooling water channel 5. Then, the process proceeds to step S140.

In step S140, the water pump 20 is stopped. Then, the process proceeds to step S150.
In step S150, the third on-off valve 23 and the fourth on-off valve 24 are closed. Then, the process proceeds to step S160.
In step S160, the second opening / closing valve 22 is opened. Then, the process proceeds to step S170.

In step S170, the operation of the water pump 20 is started. This completes the transition to the heat exchange state. Then, this routine ends.
Next, the switching determination control between the heat exchange state and the heat retaining state in the control unit 40 will be described with reference to FIG.
FIG. 6 is an example of a map for switching determination between the heat exchange state and the heat insulation state.

  Based on the vehicle state, the battery temperature input from the battery temperature sensor 30, and the outside air temperature input from the outside air temperature sensor 31, the control unit 40 switches between the heat exchange state and the heat insulation state. In the present embodiment shown in FIG. 1, there is one battery temperature sensor 30, but each battery 4 may be provided with a battery temperature sensor 30, and the highest value among the detected battery temperatures may be used as the battery temperature. The average temperature may be the battery temperature.

The switching determination between the heat exchange state and the heat retention state is performed using a map as shown in FIG.
As shown in FIG. 6, threshold values set at each vehicle state, specifically when stopped, running, and starting (in FIG. 6, line A: when stopped, line B: when starting, line C: while traveling) If the battery temperature or the outside air temperature is higher (the region on the right side or the upper side than each line A to C in FIG. 6), it is determined that the heat exchange state is established, and if the battery temperature or the outside air temperature is low (each line A in FIG. 6). In the region on the left side or the lower side of the. That is, when the battery temperature is equal to or higher than a threshold value (lines A to C in FIG. 6) set based on the outside air temperature in each vehicle state, the heat exchange state is determined, and when the battery temperature is lower than the threshold value, heat is It is determined that it is in an exchange state.

Further, the threshold value at start (line A) and the threshold value at stop (line B) are set such that the battery temperature decreases as the outside air temperature increases and the battery temperature increases as the outside air temperature decreases. Has been.
Furthermore, the threshold value based on the outside air temperature is set lower at the time of starting than at the time of stopping.
Specifically, at the time of start-up, the battery temperature is switched to a heat exchange state and a heat insulation state at a temperature lower than the appropriate temperature range, and at a stop, the outside air temperature is lower than the appropriate temperature range even when the battery temperature is within the appropriate temperature range. Switch between heat exchange and heat insulation.

  In addition, when the battery temperature and the outside air temperature are both in the appropriate temperature range or higher than the appropriate temperature range at both the start time and the stop time, the heat exchange state is determined. For example, the upper limit temperature (on the high temperature side) of the appropriate temperature range is approximately 50 degrees Celsius for lead batteries and nickel metal hydride batteries, and approximately 60 degrees Celsius for nickel cadmium batteries and lithium ion batteries. Further, the lower limit temperature (low temperature side) of the appropriate temperature range is approximately −15 degrees to −20 degrees Celsius for lead batteries, nickel cadmium batteries and lithium ion batteries, and −5 degrees Celsius for nickel hydrogen batteries.

Also, during traveling, regardless of the outside air temperature, if the battery temperature is higher than a threshold (constant value) set to a temperature slightly lower than the lower limit value of the appropriate temperature range, it is determined that the heat exchange state, When it is less than the threshold value, it is determined that the temperature is kept.
Further, when the outside air temperature is extremely high (a temperature significantly higher than the appropriate temperature range of the battery temperature), it is determined that the temperature is kept within the appropriate temperature range of the battery temperature when starting and stopping (in FIG. 6). Area above the line D).

Then, when the battery temperature exceeds the threshold set based on the vehicle state and the outside air temperature and the heat exchange state is changed to the heat insulation state, the switching control shown in FIG. 4 is executed, and the heat exchange state is changed to the heat exchange state. When the change is made, the switching control shown in FIG. 5 is executed.
As described above, in the present embodiment, when the vehicle is stopped or started, the temperature control device 1 of the in-vehicle battery is switched between the heat exchange state and the heat retention state based on the battery temperature and the outside air temperature.

  For example, when the battery temperature is within the appropriate temperature range but the outside air temperature is low, such as immediately after stopping from running in a cold region, the heat exchange state is maintained in the prior art disclosed in Patent Document 1. On the other hand, in the present embodiment, when the battery temperature is within the appropriate temperature range, but the outside air temperature is lower than the appropriate temperature range, the temperature is set to the heat retention state, so that the decrease in the battery temperature is suppressed. Can do.

In addition, when the battery temperature is lower than the appropriate temperature range and the outside air temperature is high when the vehicle is stopped, the heat exchange state is set in the present embodiment, so the battery temperature is raised by the heat of the outside air and the battery temperature is set within the appropriate temperature range. Can be as close as possible.
Thus, since the heat exchange state and the heat retention state are switched based not only on the battery temperature but also on the outside air temperature, the battery temperature can be maintained at an appropriate temperature when the vehicle is stopped.

Further, at the time of start-up, similarly to when the vehicle is stopped, the heat exchange state and the heat insulation state are switched based on the battery temperature and the outside air temperature, and further, the battery temperature is switched to the heat insulation state at a lower temperature than when the vehicle is stopped. This is because the battery temperature rises due to energization at start-up, and the battery temperature can be maintained within an appropriate temperature range even if the battery temperature is low and the heat exchange state.
In addition, at the time of start-up, when the battery temperature is lower than the appropriate temperature range and the outside air temperature is high, the conventional technique shown in Patent Document 1 enters the heat retaining state, but in this embodiment, the heat exchange state is set. The battery temperature can be raised by the heat of the outside air to quickly approach the appropriate temperature range.

Also, when the outside air temperature is significantly higher than the appropriate temperature range of the battery temperature at the time of stopping and starting, the battery is switched to the heat retaining state when the battery temperature is within the appropriate temperature range. Can be prevented from rising beyond the appropriate temperature range.
As described above, in the present embodiment, the temperature control device 1 of the in-vehicle battery is switched between the heat exchange state and the heat retention state based on the battery temperature and the outside air temperature, so that the switching can be appropriately performed at the time of stopping or at the time of starting. The battery can be brought to an appropriate temperature, and the battery performance can be improved.

In the present embodiment, the temperature control device 1 of the in-vehicle battery is switched depending on the battery temperature regardless of the outside air temperature during traveling. This is because the battery temperature and the outside air temperature substantially coincide with each other during traveling because the heat exchange rate in the heat exchanger is high due to traveling wind. Therefore, it is possible to accurately and easily determine the heat exchange state and the heat retention state only from the battery temperature.
Further, in the present embodiment, since the lower cooling water tank 8 is located below the internal cooling water channel 5, when switching from the heat exchange state to the heat retaining state, the valve is simply opened without operating the water pump 20. The cooling water can be moved by its own weight. Thereby, power consumption can be suppressed.

In addition, this invention is not limited to the said embodiment.
For example, the map for determining whether to switch between the heat exchange state and the heat retention state may have a region other than that shown in FIG. 6 for determination based on the battery temperature and the outside air temperature, depending on the performance of the temperature control device, the battery capacity, and the like. May be changed as appropriate.
Further, the configuration of the temperature control device may be changed as appropriate so that the lower cooling water tank 8 is arranged outside the battery pack 2 or other than below the internal cooling water channel 5.

  In the present embodiment, the battery pack 2 is a battery for supplying power to the travel drive motor. However, the present invention can be widely applied to an in-vehicle battery that exchanges heat with the outside air via a heat medium.

DESCRIPTION OF SYMBOLS 1 Temperature control apparatus 2 Battery pack 4 Battery 5 Internal cooling water channel (heat-medium channel)
20 Water pump (switching device)
21 First open / close valve (switching device)
22 Second open / close valve (switching device)
23 Third open / close valve (switching device)
24 Fourth open / close valve (switching device)
40 Control unit (control device)

Claims (3)

A temperature control device for an in-vehicle battery comprising a heat medium path that allows a heat medium to pass around a battery mounted on a vehicle, and a heat exchanger that exchanges heat between the heat medium that has passed through the heat medium path and outside air,
A heat exchange state in which the heat medium is circulated between the heat medium path and the heat exchanger to exchange heat between the outside air and the battery via the heat medium; and the heat medium is discharged from the heat medium path. A switching device for switching to a heat retaining state that suppresses heat exchange between the outside air and the battery via the heat medium;
The operating controls the switching device based on the temperature and the ambient temperature of the battery, and a control device for setting the switching between the heat retaining state and the heat exchange state,
The control device sets the switching device to the heat exchange state when the temperature of the battery is equal to or higher than a threshold set based on the outside air temperature, and when the temperature of the battery is lower than the threshold, Set the switching device to the heat retaining state,
The battery is a power supply source at the start of the vehicle,
The temperature control device for an in-vehicle battery is characterized in that the threshold is set higher as the outside air temperature decreases and is set lower than when the vehicle is stopped when the vehicle is started . The on-vehicle battery temperature control device according to claim 1 , wherein the threshold value is set to a constant value regardless of the outside air temperature while the vehicle is running. The temperature control device for an in-vehicle battery according to claim 1 or 2 , wherein the control device sets the heat insulation state when an outside air temperature is higher than an appropriate temperature range set according to characteristics of the battery. .

Images