JP6344556B2 - Battery heating device for hybrid vehicle - Google Patents

Description

  The present invention relates to a battery heating device for a hybrid vehicle that heats a battery.

A hybrid vehicle equipped with an engine, a motor, and a battery pack (battery) has EV driving (running by battery power) and series driving (power generated by engine driving) according to the driving state and the amount of power of the battery pack. ) And parallel travel (travel that assists engine travel by motor drive).
By the way, it is known that the output of a battery pack mounted on a vehicle decreases at low temperatures. Therefore, in the hybrid vehicle, air heated by the heater element is supplied to the inside of the battery pack at a low temperature to warm the internal battery module.

  However, the output of the heater element is limited. For this reason, it is difficult to maintain an appropriate temperature in a driving environment in which the amount of heat of the battery pack that escapes to the outside increases, such as driving in a cryogenic environment where the outside air temperature is extremely low, especially at high speeds. The battery temperature cannot be kept at the target temperature (because the battery pack is easily affected by the driving wind). Therefore, the battery pack cannot secure the target output characteristics (decrease in battery output), and there is a concern that the power performance of the vehicle will deteriorate.

  Therefore, a technique has been proposed in which air around the engine is circulated around the battery pack using the introduction duct as in Patent Document 1, and the air that has passed through the battery pack is returned from the return duct to the middle of the path of the introduction duct. Yes. That is, the battery pack is warmed from the surroundings by the waste heat of the engine.

JP 2013-180614 A

However, in Patent Document 1, since the air after passing through the battery pack is joined in the middle of the air flow toward the battery pack, the temperature of the air introduced to the periphery of the battery pack is likely to decrease. With this, the battery pack is not sufficiently warmed, and the battery temperature hardly reaches the target temperature.
Accordingly, an object of the present invention is to provide a battery heating device for a hybrid vehicle in which the battery is efficiently warmed by the air that has passed around the engine.

An aspect of the present invention relates to a battery heating device for a hybrid vehicle provided with an engine provided in front of the vehicle , a blower that blows air to the engine, and a battery that drives the driving motor, and is blown by the blower and passes around the engine. and a waste heat introduction passage for guiding air to the surroundings of the battery, comprising a return path for the air passing through the periphery of the battery back to the blowing direction windward of the engine, an exhaust pipe extending from the engine to the rear of the vehicle, the return path The vehicle is adjacent to the exhaust pipe from the rear of the vehicle to the front of the vehicle (claim 1).

Good Mashiku includes outside air temperature detection unit for detecting an outside air temperature, and further comprising a battery temperature detecting unit for detecting the temperature of the battery, the blower unit includes a running wind introduction portion for guiding running wind to the engine, the outside air temperature There when: the temperature of the battery, close the running wind introduction part was to have a closing shutter (claim 2).

Preferably, the apparatus further includes a first damper portion that is provided in the waste heat introduction path and switches a flow direction of the air that has passed around the engine, and a control portion that controls the first damper portion. When the temperature of the battery is below a predetermined temperature, the first damper unit is controlled so that the air that has passed around the engine is guided to the periphery of the battery. When the temperature of the battery is equal to or higher than the predetermined temperature, the air that has passed around the engine is The first damper portion is controlled so as to lead to the return path ( claim 3 ).

Preferably, the vehicle is further provided with a second damper portion that is provided on the vehicle rear side of the return path and opens and closes between the return path and the atmosphere, and the control unit has the second damper portion when the temperature of the battery is lower than a predetermined temperature. The second damper portion is controlled to be opened when the temperature of the battery is equal to or higher than a predetermined temperature ( Claim 4 ).

According to the present invention, the air containing the waste heat of the engine room is not only led to the periphery of the battery, but also after the heat exchange with the battery, the air is returned to the windward side of the engine in the ventilation direction, and again by the waste heat of the engine. After being heated, it is led around the battery again.
Therefore, the battery can be efficiently heated by recirculation of the air that has passed around the battery. In particular, since the return path is along an exhaust pipe extending from the engine provided in the front of the vehicle to the rear of the vehicle, the return air is forwarded from the rear of the vehicle to the front by the engine waste heat by using a route to return to the front of the engine. Thus, the battery pack can be heated by fully utilizing the waste heat of the engine.

The figure which shows the structure of the battery heating apparatus used as the aspect which concerns on one Embodiment of this invention with the flow of air in normal time (the request | requirement of battery heating is not required). The flowchart which shows the control in which a battery is heated with the waste heat of an engine at the time of the request | requirement of battery heating. The figure which shows the flow of the air at the time of the battery heating.

Hereinafter, the present invention will be described based on an embodiment shown in FIGS.
FIG. 1 shows a hybrid vehicle to which the present invention is applied. The hybrid vehicle includes a vehicle body 1 having an engine room 3 at the front and a vehicle compartment 5 at the center. The engine room 3 houses an engine 7 and a generator driven by the engine 7 (not shown). Of course, the engine 7 includes an intake manifold (not shown), an exhaust manifold (not shown), an exhaust pipe 7a extending from the exhaust manifold to the rear of the vehicle, a catalyst (not shown), and the like.

  A radiator 9 is provided on the front side of the engine 7 together with an electric radiator fan 9a. At the front end of the engine room 3 facing the radiator 9, a grill 11 (corresponding to the opening of the present application) having an opening 11a for introducing running air is provided. As a result, traveling wind generated by traveling the vehicle and wind generated by the operation of the radiator fan 9a are introduced into the engine room 3. That is, the grill 11 and the radiator fan 9a serve as a blowing section, and the blowing is performed from the front side of the vehicle to the engine 7. Incidentally, the radiator fan 9a operates under various conditions of the engine 7, but here it is assumed that the radiator fan 9a operates in accordance with the operation of the engine 7 in order to simplify the description.

  A battery pack 13 serving as a traveling battery is provided below the vehicle body 1, for example, below the floor 5 a of the passenger compartment 5. An under cover 13 a is provided immediately below the lower portion of the battery pack 13 so as to cover the entire lower surface of the battery pack 13. The battery pack 13 is configured, for example, by accommodating a large number of battery modules 14b in a flat battery case 14a. The peripheral edge of the under cover 13a is fixed to the lower surface of the floor 5a. Incidentally, although not shown, a device for circulating the air heated by the heater element inside the battery case 14a is housed inside the battery case 14a.

Below the floor 5 a at the rear of the vehicle body 1, a traveling motor 15 (for example, a three-phase AC synchronous motor: hereinafter simply referred to as a motor 15), a DC voltage of the battery pack 13 is converted into an AC voltage and supplied to the motor 15. An inverter 17 and the like are provided.
The hybrid vehicle is equipped with a control unit 19 composed of, for example, a microcomputer. The control unit 19 performs control for executing various travel modes such as an EV travel mode, a series travel mode, and a parallel travel mode based on the engine speed and the throttle opening representing the driving state of the vehicle, and the battery power amount. Is set. Incidentally, the EV traveling mode here is a traveling mode in which the motor 15 is driven by the electric power stored in the battery pack 13 when traveling at a low load, for example, and the series traveling mode is an electric power amount of the battery pack 13. When a decrease or high power is required, the engine 7 drives a generator (not shown) and the motor 15 is driven by the generated power to travel. The parallel travel mode is, for example, when driving at a high load. A traveling mode in which the vehicle travels with the driving force of the engine 7 and assists the engine traveling with the driving force of the motor 15.

Further, the hybrid vehicle is equipped with a battery heating device 21 that warms the battery pack 13 from the surroundings using engine waste heat in the engine room 3. FIG. 1 shows a normal state (not requiring battery heating) in the battery heating device 21, and FIG. 3 shows a state when the battery pack 13 is heated.
Referring to FIGS. 1 and 3, the main configuration of the battery heating device 21 will be described. Of the fixed portions 23 a fixing the lower surface of the floor 5 a surrounding the battery pack 13 and the peripheral portion of the under cover 13 a, For example, a waste heat introduction port 23b provided in the front part of the vehicle similarly indicates a waste heat outlet port provided in the rear part of the vehicle, for example.

  A waste heat introduction path 25 communicates between the waste heat introduction port 23a and the engine room 3 portion in front of the entrance 23a. The waste heat introduction path 25 is formed by, for example, an introduction duct portion 25 a that passes under the dash panel 4 that partitions the engine room 3 and the vehicle compartment 5. And one end part used as the inlet_port | entrance of the introduction duct part 25a faces the rear part (vehicle rear side) of the engine 7, for example, and the other end part used as an exit is connected with the waste heat introduction port 23a.

  In this introduction duct portion 25a, the air that has passed around the engine 7 in the engine room 3 as the vehicle travels and the radiator fan 9a is operated is surrounded by the battery pack 13, that is, the battery case 14a, the floor 5a, and the undercover. It is made to flow into a gap between the terminal 13a. Thereby, the waste heat of the engine 7 is transmitted to the internal battery module 14b via the battery case 14a. That is, the battery module 14b is heated by engine waste heat.

  In addition, the battery pack 13 is provided with a return path 27 for returning the air after heat exchange with the battery pack 13. The return path 27 is formed from a lead-out duct portion 27 a that continuously extends from the waste heat lead-out port 23 b to the engine 7. Specifically, the return path 27 is formed, for example, by a lead-out duct part 27a that reaches the waste heat outlet 23b through the bottom face of the engine 7, the bottom face of the waste heat introduction path 25, and the bottom face of the under cover 13a. Here, the lead-out duct portion 27a is disposed adjacent to the exhaust pipe 7a extending from the engine 7 to the rear of the vehicle, specifically along the exhaust pipe 7a.

  The rear end of the return path 27 and the waste heat outlet 23b of the battery pack 13 are in communication with each other via an exhaust damper 29 (corresponding to the second damper portion of the present application). The exhaust damper 29 is a rotary damper that can be opened and closed between the waste heat outlet 23b and the rear end of the return path 27 and the atmosphere opening 28 that opens to the atmosphere. In FIG. 1, “a” indicates an atmospheric release position where the exhaust heat outlet 23 b and the rear end portion of the return path 27 and the atmospheric release port 28 communicate with each other among the operating positions of the damper, and “b” in FIG. The air release port portion 28 is closed, and a communication position where the waste heat outlet port 23b and the rear end portion of the return path 27 communicate with each other is shown. That is, the air that has passed around the battery pack 13 is introduced into the return path 27 by the exhaust damper 29 at the position b. Further, the rear end portion on the inlet side of the return path 27 is opened to the atmosphere by the exhaust damper 29 at the position a.

  The front end portion of the return path 27 extends to the suction side of the radiator 9 that is the windward side of the engine 7 and the outlet formed at the front end is disposed on the suction side of the radiator 9. Thereby, the air that has passed through the battery pack 13 returns to the upwind direction of the engine 7 in the blowing direction. That is, the air that has finished heat exchange with the battery pack 13 is again heated by the waste heat of the engine 7.

  The grill 11 includes, for example, a rotary grill shutter 31 (corresponding to the open / close shutter of the present application) that opens and closes the opening 11 a of the grill 11. The grill shutter 31 closes the opening portion 11a when the outside air temperature detected by the outside air temperature sensor 42 becomes equal to or lower than the battery temperature. As a result, when the opening 11a of the grill 11 is closed in a state where the engine room 3, the waste heat introduction path 25, the battery pack 13 and the return path 27 are in communication (FIG. 3), a closed space is formed. The engine room 3, the waste heat introduction path 25, the gap around the battery pack 13, and the return path 27 are closed spaces. That is, the air that has passed through the engine 7 circulates around the battery pack 13 in a closed space.

  Further, a switching unit 33 for deriving engine waste heat to the outside as shown in FIG. 1 and FIG. 3 is provided in the waste heat introduction path 25 so as to respond to normal time when heating (heating) of the battery pack 13 is not required. Is provided. That is, the switching unit 33 includes a waste heat introduction damper 37 (corresponding to the first damper unit of the present application). Here, the waste heat introduction damper 37 is, for example, a waste heat introduction position (c position in FIG. 3) that connects the waste heat introduction path 25 and the waste heat introduction port 23a shown in FIG. The waste heat extraction position (d position in FIG. 1) that communicates the heat introduction path 25 and the switching port 35 formed in the duct portion of the return path 27 is configured to be a rotatable damper.

  Thus, when the battery pack 13 needs to be heated, the waste heat introduction damper 25 communicates with the waste heat introduction path 25 and the waste heat introduction port 23a as shown in FIG. Thus, the air containing the engine waste heat in the engine room 3 is guided to the battery pack 13. When heating of the battery pack 13 is not required, the waste heat introduction damper 25 communicates with the waste heat introduction path 25 and the switching port 35 as shown in FIG. 1, and the waste heat introduction port 23a is closed. Thus, the air that has passed around the engine in the engine room 3 does not go to the battery pack 13 but is introduced into the return path 27 from the reverse direction. More specifically, the engine waste heat is led to the atmosphere through the return path 27 in cooperation with the exhaust damper 29 (second damper portion) that is opened to the atmosphere.

  The control unit 19 is set to control the grill shutter 31 and the dampers 29 and 37 in response to a request for heating or non-request (normal time) of the battery pack 13. This includes, for example, a battery temperature sensor 39 that detects the battery temperature (battery module temperature), a sensor that determines whether or not the engine 7 is operating, for example, an introduction that detects the temperature of the air introduced into the waste heat introduction passage 25. Setting that introduces engine waste heat into the battery pack 13 when the air temperature sensor 41 and the outside air temperature sensor 42 that detects the outside air temperature (corresponding to the outside air temperature detecting unit of the present application) are required. Is used.

  Specifically, the control part 19 sets the heating permission temperature value Th as a threshold value which prescribes | regulates the battery heating start, for example. When the battery heating is not required, the normal mode, that is, the grill shutter 31 is opened from the determination that the battery temperature is equal to or higher than a predetermined temperature (in this case, exceeds the outside air temperature), that is, the heating permission temperature value Th or higher. The waste heat introduction port 23a is closed (switching port 35: open), and the rear end portions of the waste heat outlet port 23b and the return path 27 are switched to the atmosphere open side. By this setting, the air in the engine room 3 does not pass around the battery pack 13 but is released from the return path 27 to the atmosphere.

Also, when the battery temperature falls below the heating permission temperature value Th, battery heating is required unlike the normal time. At this time, if the air temperature introduced into the battery pack 13 is higher than the battery temperature, it is determined that the waste heat of the engine 7 is secured, and the battery heating mode is executed. Further, since the outside air temperature is equal to or lower than the battery temperature, the grill shutter 31 is set to be closed.
Specifically, in the battery heating mode, the waste heat introduction port 23a is opened (switching port 35: closed), and the mode is switched to the side where the waste heat outlet port 23b and the rear end portion of the return path 27 communicate with each other. The grill shutter 31 is closed so that the air in the engine room 3 circulates around the battery pack 13 in the closed space. Incidentally, the grille shutter 31 is set in a plurality of stages, and the opening degree of the grille shutter 31 can be set in a plurality of stages. It is also conceivable to vary the opening. When the outside air temperature is higher than the battery temperature, the grille shutter 31 is opened, the waste heat introduction port 23a is opened (switching port 35: closed), and the waste heat outlet port 23b is communicated with the rear end of the return path 27. As a mode for switching to the side to perform, outside air temperature may be taken in.

The more specific control of battery heating is shown in the flowchart of FIG.
The control will be described in detail with reference to FIG. 2. In step S1, the battery temperature (battery module temperature) Tb is detected from the battery temperature sensor 39, and in the subsequent step S3, the engine room is detected from the introduction air temperature sensor 41. The air temperature Tin in 3 is detected.

At this time, the hybrid vehicle is running in a series running (running with the generated power that drives the generator with the engine) or parallel running (running that assists the engine running with the motor drive) under normal outside air temperature. To do.
At this time, since the battery temperature is rising (exceeding the outside air temperature), heating of the battery pack 13 by waste heat of the engine 7 is not necessary.

  Explaining this point, in the following step S5, the battery temperature Tb is compared with the battery heating permission temperature value Th to determine whether or not the battery heating is present. At this time, the battery temperature Ttb exceeds the outside air temperature, The behavior which becomes higher than heating permission temperature value Th is shown. Therefore, the process proceeds from step S5 to step S7, and the control unit 19 sets the exhaust damper 29 to “open”, the grill shutter 31 to “open”, and the waste heat introduction damper 37 to “close” as shown in FIG.

  Then, the air that has passed around the engine 7 is introduced from the switching port 35 to the return path 27 from the direction opposite to the flow direction of the return path 27. Thereby, the air is led out to the atmosphere through the return path 27 from the atmosphere opening port 28 at the end of the return path 27. That is, normally, the air that has passed around the engine is not sent to the battery pack 13. Further, the waste heat outlet 23b is opened to the atmosphere, and a countermeasure suitable for normal times, that is, a countermeasure for suppressing the temperature rise of the battery pack 13 is taken.

On the other hand, it is assumed that the hybrid vehicle travels at a high speed (series travel or parallel travel), for example, in a cryogenic environment.
A hybrid vehicle that is traveling at a high speed under an extremely low temperature is in a situation where it is difficult to maintain the battery temperature Tb at an appropriate temperature. For this reason, unlike normal time, the battery temperature Tb is lower than the outside air temperature or the battery heating permission temperature Th. Therefore, the process proceeds from step S5 to step S9.

  In step S9, the battery temperature Tb is compared with the temperature Tin of the air introduced into the battery pack 13. Here, the air temperature (corresponding to the introduced air temperature Tin) in the engine room 3 in the hybrid vehicle running at high speed is calculated. Since the temperature rises due to the waste heat generated in the engine 7, the behavior becomes higher than the battery temperature Tb. Thus, the control unit 19 determines that the air introduced into the battery pack 13 has heat that can heat the battery pack 13. Of course, it is also determined that engine waste heat that can heat the battery pack 13 is secured.

Thereby, it progresses from step S9 to step S11. Then, the control unit 19 “closes” the exhaust damper 29, “closes” the grill shutter 31, and “opens” the waste heat introduction damper 37 as shown in FIG.
With this control, as shown in FIG. 3, the engine room 3, the waste heat introduction path 25, the gap around the battery pack 13, and the return path 27 become closed spaces disconnected from the outside. Under this closed space, the air that has passed around the engine as shown by the arrow in FIG. Led. Heat exchange is performed while this air passes through the gap between the battery case 14a and the floor 5a or the under cover 13a, and the battery module 14b in the battery case 14a is warmed by engine waste heat.

The air that has passed through the battery pack 13 (temperature reduction due to heat exchange) passes through the return path 27 from the waste heat outlet 23b, and is sucked into the radiator 9 disposed in front of the engine 7, that is, on the wind direction of the engine 7 Return to the side. Incidentally, when passing through the return path 27, the air is heated (heated) by receiving the heat of the exhaust gas flowing through the adjacent exhaust pipe 7a.
The air that has returned to the engine room 3 is heated again when it passes around the engine 7. Then, the cycle of being guided to the battery pack 13 again and circulating around the battery pack 13 is repeated.

Thus, when battery heating is required, the battery pack 13 can efficiently heat the air that has passed around the engine by using the recirculation heating of the air that has passed around the battery. Thereby, even when traveling at a high speed in a cryogenic environment, the battery temperature can be maintained at the target temperature.
Therefore, it is possible to suppress a decrease in battery output under a cryogenic environment of the hybrid vehicle, and it is possible to suppress a decrease in vehicle running performance. In particular, when battery heating is required (when the outside air temperature is lower than the battery temperature), the grille shutter 31 is used to close the engine room 3, the waste heat introduction path 25, the gap around the battery pack 13, and the return path 27. Thus, the waste heat of the engine 7 can be transmitted to the battery pack 13 most effectively.

Further, by arranging the return path 27 along the exhaust pipe 7a extending from the engine 7 provided in the front of the vehicle to the rear of the vehicle (adjacent arrangement), the return air is supplied to the engine 7 by using the path to return to the front of the engine. The waste heat can be heated from the rear to the front of the vehicle, and the battery pack 13 can be heated by fully utilizing the waste heat of the engine 7.
In addition, when there is no request for heating of the battery pack 13, the engine waste heat in the engine room 3 is led out to the outside (atmosphere). Temperature rise is suppressed. Therefore, battery heating is compatible with normal times. In particular, the return path 27 is circulated in the reverse direction by using a waste heat introduction damper 37 that connects the engine room 3 and the exit side of the return path 27 and an exhaust damper 29 that opens the vehicle rear side of the return path 27 to the atmosphere. Since the waste heat of the engine is led out to the outside by the method, the waste heat from the engine 7 can be discharged outside the vehicle without hitting the battery pack 13.

It should be noted that each configuration and combination thereof in the above-described embodiment is an example, and the addition, omission, replacement, and other changes of the configuration are possible without departing from the spirit of the present invention. Needless to say. Further, the present invention is not limited by the embodiment, and it is needless to say that the present invention is limited only by the “claims”.
For example, in one embodiment, the case where battery heating (heating) is required has been described as an example of high-speed traveling at an extremely low temperature. However, the present invention is not limited to this. In one embodiment, although the hybrid vehicle which has a device which warms the inside of a battery pack using a heater element was mentioned, the present invention may be applied to a hybrid vehicle without the device.

1 Car body 7 Engine 7a Exhaust pipe 9a, 11 Radiator fan, grill (blower part)
11a Opening 13 Battery pack (battery)
15 Motor (traveling motor)
19 Control section 25 Waste heat introduction path 27 Return path 29 Exhaust damper (second damper section)
31 Grill shutter (opening / closing shutter part)
37 Waste heat introduction damper (first damper part)
41 Inlet air temperature sensor (battery temperature detector)
42 Outside temperature sensor (outside temperature detector)

Claims (4)

In a battery heating device for a hybrid vehicle provided with an engine provided in front of the vehicle , a blower for blowing air to the engine, and a battery for driving a driving motor,
A waste heat introduction path that guides air that has been blown by the blower and passed around the engine to the periphery of the battery;
A return path for returning the air that has passed around the battery to the windward side of the engine in the air blowing direction;
An exhaust pipe extending from the engine to the rear of the vehicle;
Equipped with,
The return path is adjacent along the exhaust pipe from the rear of the vehicle to the front of the vehicle.
Battery heating system for a hybrid vehicle, wherein the. An outside air temperature detector for detecting outside air temperature,
A battery temperature detecting unit for detecting the temperature of the battery;
The blowing section is
A traveling wind introduction section for guiding traveling wind to the engine;
When the outside air temperature is equal to or lower than the temperature of the battery, an open / close shutter that closes the traveling wind introduction portion,
The battery heating device for a hybrid vehicle according to claim 1, comprising: A first damper portion provided in the waste heat introduction path and switching a flow direction of air that has passed around the engine;
A control unit for controlling the first damper unit;
The controller is
When the temperature of the battery is lower than a predetermined temperature, the first damper unit is controlled to guide the air that has passed around the engine to the periphery of the battery,
3. The hybrid vehicle battery according to claim 2 , wherein when the temperature of the battery is equal to or higher than a predetermined temperature, the first damper unit is controlled so as to guide air that has passed around the engine to the return path. 4. Heating device. A second damper portion that is provided on the vehicle rear side of the return path and opens and closes between the return path and the atmosphere;
The controller is
When the temperature of the battery is lower than a predetermined temperature, control to close the second damper part,
The battery heating device for a hybrid vehicle according to claim 3 , wherein when the temperature of the battery is equal to or higher than a predetermined temperature, the second damper unit is controlled to be opened.

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