Battery cooling structure

The invention relates to a battery cooling structure for cooling a battery mounted in a vehicle. This battery cooling structure includes a battery pack (20) within which the battery is housed in an internal space; an air supplying device (26) that is configured to send cooling air to the battery pack (20); and an air exhausting device (30) is configured to discharge exhaust air from the battery pack (20). The battery pack (20) is arranged under a rear seat (10) of the vehicle. An exhaust vent (54) of the air exhausting device 30) is provided on a floor surface in a rearward space behind the rear seat (10) in the vehicle, and discharges the exhaust air from the battery pack (20) upward into the rearward space from the exhaust vent (54) provided in the floor surface.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a battery cooling structure for cooling a battery mounted in a vehicle.

2. Description of Related Art

Vehicles such as hybrid vehicles (HV) and electric vehicles (EV) run by driving a motor using electric power from a battery. Therefore, a battery that ensures the necessary electric power is mounted in the vehicle. Also, in order to improve the battery mounting space efficiency, Japanese Patent Application Publication No. 2010-036723 (JP 2010-036723 A) proposes to house the battery under a rear seat. Also, a battery generates heat as it charges and discharges. In particular, with a battery for a vehicle, large current often flows, so the amount of heat generated is large. If the temperature of the battery becomes high, the battery will deteriorate, so it is necessary to provide a structure to cool the battery. JP 2010-036723 A describes a structure that draws air into a vehicle cabin from in front of a lower portion of the rear seat, and discharges this air out of the vehicle from behind a lower portion of the rear seat.

SUMMARY OF THE INVENTION

Here, if exhaust air that has cooled the battery under the rear seat is discharged out of the vehicle as it is, the exhaust passage is able to be short, which is advantageous in terms of space, and pressure loss is low, so it is efficient. However, with this configuration, an exhaust vent is arranged in a relatively low position, so sufficient consideration must be given so that foreign matter and water and the like on the road does not get into the battery pack.

Therefore, one aspect of the invention relates to a battery cooling structure for cooling a battery mounted in a vehicle. This battery cooling structure includes a battery pack, an air supplying device, and an air exhausting device. The battery pack houses the battery in an internal space, and is arranged under a rear seat of the vehicle. The air supplying device is configured to send cooling air to the battery pack. The air exhausting device is configured to discharge exhaust air from the battery pack. An exhaust vent that discharges the exhaust air is provided in a floor surface in a rearward space behind the rear seat in the vehicle. The exhaust vent is configured to discharge the exhaust air from the battery pack upward into the rearward space from the exhaust vent.

Also, in the battery cooling structure described above, the rearward space may be a luggage space of the vehicle, and a spare tire housing space may be provided in a lower portion of the luggage space. Also, the exhaust vent may be positioned in front of the spare tire housing space.

Also, in the battery cooling structure described above, the air exhausting device may have an exhaust air duct that extends from the battery pack to the rearward space, and an exhaust port of the exhaust air duct may be provided underneath the floor surface and open into a discharge duct that extends in a vehicle width direction. The discharge duct may have a discharge port in a position planarly offset with respect to the exhaust port on a front surface side of the discharge duct. After exhaust air discharged from the exhaust port of the exhaust air duct flows through the discharge duct in a direction parallel to the floor surface in the vehicle width direction, the exhaust air may be discharged upward into the rearward space via the discharge port and the exhaust vent.

Also, in the battery cooling structure described above, the discharge port of the exhaust air duct may be covered by cloth. Also, in the battery cooling structure described above, the discharge port of the exhaust air duct may be covered by lattice. Furthermore, in the battery cooling structure described above, the discharge port of the exhaust air duct may be provided in a direction excluding in front, with respect to a vehicle longitudinal direction, of the exhaust port, and a closed portion may be provided in front, with respect to the vehicle longitudinal direction, of the exhaust port.

This kind of battery cooling structure makes it possible to effectively inhibit foreign matter and the like from getting in through the exhaust vent.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, example embodiments of the invention will be described with reference to the accompanying drawings. The invention is not limited to the example embodiments described here.

First, the structure related to supply air and exhaust air in a battery cooling structure of this example embodiment will be described.FIGS. 1A and 1Bare views of the structure related to the flow of supply air and exhaust air to and from a battery pack in this example embodiment.

A rear seat10includes a seat cushion10a, a seatback10b, and a battery housing space10cbelow the seat cushion10a. The front and sides of the battery housing space10care surrounded by a lower trim12. Also, a vehicle body14is positioned on a bottom surface side of the battery housing space10c.

A battery pack20is arranged inside of the battery housing space10c, and a battery stack22is arranged inside of this battery pack20. This battery stack22is formed by a plurality of battery modules24connected together in series.

The inside of the battery pack20is sealed by a lower case and an upper cover. A supply air flow path is formed above the battery stack22and an exhaust air flow path is formed below the battery stack22.

A supply air duct26is connected to a rear side of the supply air flow path above the battery stack22inside the Battery pack20, as shown inFIG. 1A, and this supply air duct26extends toward the rear and is connected to a blowing side of a blower28.

An exhaust air duct30is connected to a rear side of the exhaust air flow path below the battery stack22of the battery pack20, as shown inFIG. 1B, and this exhaust air duct30extends toward the rear, with an exhaust port32opening upward.

A rear side (back) space of the seatback10bof the rear seat10serves as a luggage space40. A floor surface of the luggage space40is formed by a deck board42. This deck board42is placed in the luggage space40, so it is able to be picked up and removed. A spare tire space44within which a spare tire is housed is provide below the deck board42, and a spare tire is housed here. Also, an accessories compartment such as a shelf is provided below the deck board42, at a front upper portion in the spare tire space44.

Also, the blower28described above is arranged behind the rear seat10and in front of the spare tire space44. That is, there is a space below the luggage space40to the rear of the rear seat10and in front of the spare tire space44, and the blower28is arranged here. An intake air duct60(seeFIG. 2) and the supply air duct26are connected to this blower28. Also, a rear side portion of the exhaust air duct30and the exhaust port32are provided. A discharge duct48that extends in a vehicle width direction is provided on an upper portion of this exhaust port32, and a discharge port panel50is provided on a front surface of this discharge duct48. This discharge port panel50has a closed portion and an open portion. The open portion is an exhaust port. An exhaust vent54formed by a gap between a tip end of the deck board42and a back surface of the seatback10babove this exhaust port is open to the luggage space40. A seat member52is provided between a lower front end of the discharge duct48and the back surface of the seatback10bso that articles will not fall down.

Here,FIG. 2is a perspective view of the battery pack20and a duct. In this case, the intake air duct60is connected to the intake side of the blower28. This intake air duct60draws in air from an inlet62in a side surface on the door side of lower trim of the rear seat10. InFIG. 2, the seat cushion10aand the lower trim12and the like shown inFIGS. 1A and 1Bhave been removed, but the inlet62is open to the door-side side surface of the lower trim12. Cloth or lattice or the like is placed over the front surface of the inlet62to prevent foreign matter from getting in from the outside.

In this way, the intake air duct60, the supply air duct26, and the exhaust air duct30are arranged in order from the door side toward the inside, in the space below the seat cushion10aof the rear seat10.

Next, the structure to the rear of the battery cooling structure of this example embodiment will be described. Here,FIGS. 3A, 3B, and 3Care views of the structure of a portion where the exhaust port32opens out. InFIG. 3A, the top of the drawing is toward the vehicle rear and the side of the drawing is in the vehicle width direction. InFIG. 3B, the top of the drawing is upward with respect to the vehicle, and the side of the drawing is in the vehicle width direction. InFIG. 3C, the top of the drawing is upward with respect to the vehicle, the left side of the drawing is toward the vehicle front, and the right side of the drawing is toward the vehicle rear.

In this way, the exhaust port32is provided in front of an accessories compartment46, and is open to a bottom surface of the discharge duct48that extends in the width direction of the vehicle. This discharge duct48has the discharge port panel50on the front side. This discharge port panel50has a discharge port50athat is covered by cloth or lattice or the like, and a closed portion50b. This discharge port50ais provided somewhere other than on (i.e., in a location excluding) the front side of the exhaust port32. The front of the exhaust port32is the closed portion50b. The discharge port panel50may be formed by a panel in which the discharge port50ais formed as an opening, or the closed portion50bmay be arranged at appropriate intervals so as to form an open portion (i.e., the discharge port50a) therebetween.

Therefore, after exhaust air from the exhaust port32temporarily curves in the width direction of the vehicle, it then flows forward toward the back surface of the seatback10bof the rear seat10. The exhaust air then passes through the exhaust vent54that is the gap between the tip end of the deck board42and the back surface of the seatback10b, and is discharged upward into the luggage space40.

Cloth or lattice may also be arranged on the upper surface of the exhaust port32so that articles will not fall into the exhaust port32. Also, the discharge port panel50is preferably able to be removed from the discharge duct48. Further, the upper end of the exhaust port32is flange-shaped and positioned above the bottom surface of the discharge duct48. By having this portion extend upward in a pipe-shape, water and the like will not reach the exhaust port32even if it gets into the discharge duct48.

Next, the flow of air in the battery cooling structure of this example embodiment will be described. Air inside the vehicle cabin is drawn in from the inlet62by driving the blower28. This air is drawn into the blower28via the intake air duct60. Discharged air from the blower28is supplied into an upper space (i.e., a supply air flow path) in the battery pack20via the supply air duct26. The battery stack22is arranged inside the battery pack20, but because there is a gap between battery modules24of the battery stack22, the air flows downward through this gap, such that the battery modules24are effectively cooled. Here, cooling air is able to be made to pass through this gap between the stacked battery modules24by closing off the area between the periphery of the battery stack22and a peripheral inside wall of the battery pack20.

Exhaust air is discharged from a lower space (i.e., an exhaust air, flow path) in the battery pack20into the luggage space40through the exhaust air duct30, the exhaust port32, the discharge duct48, the discharge port panel50, and the exhaust vent54that is the gap between the tip end of the deck board42and the back surface of the seatback10b. In this example, the exhaust vent54is positioned along almost the entire width in the width direction of the vehicle, but it may also be limited to only a specific portion.

Next, the individual structures of the battery cooling structure of this example embodiment will be described. InFIGS. 1A and 1B, only one rear seat10is shown, but normally there are two rear seats10, and battery packs20, as well as a mechanism for cooling the battery packs20, are arranged with the same configuration under the rear seats10, as shown inFIGS. 1A and 1B.

Here,FIGS. 4A, 4B, and 4Care views of the exteriors of the exhaust air duct30, the supply air duct26, and the intake air duct60, respectively. As shown inFIG. 4A, the exhaust air duct30extends toward the rear from a rear end of a lower case that forms a bottom surface of the battery pack20. As shown in the drawing, a front end of the exhaust air duct30is a flat opening that is vertically narrow (i.e., narrow in the vehicle height direction) and wide (in the vehicle width direction). Air from the whole discharge flow path below the battery stack22is discharged from this opening. The width of the exhaust air duct30gradually narrows toward the exhaust port32, and the exhaust port32is a generally square-shaped opening.

Also, a periphery of an open portion30aof the front end of the exhaust air duct30is reinforced by a flange portion30b. This open portion30ais able to be connected to the discharge flow path in an airtight manner by placing the lower side of the flange portion30bclose against the lower case and holding the upper side of the flange portion30bdown against the rear side end portion of the battery stack22. A side portion of the flange portion30bis connected in an airtight manner to an inside wall of an upper cover that covers a side portion and an upper portion of the battery pack20. An airtight seal is achieved by arranging a sealant around the flange portion30b.

A more reliable seal is achieved by providing a recessed portion that is recessed downward in two locations as shown inFIG. 4A, on an upper edge portion of the flange portion30b, and adjusting the shape of a lower surface of the rear end of the battery stack22accordingly. Also, having the recessed portion directly contact the lower edge portion of the flange portion gives the flange portion30bsufficient strength.

The front end of the supply air duct26is a flat open portion26athat is vertically narrow and wide in the width direction, matching the shape of the upper space (i.e., the supply air flow path) of the battery pack20, as shown inFIG. 4B. Also, a flange portion26bis formed around the open portion26a, and the periphery of this flange portion26bis sealed via a sealant between the rear upper end portion of the battery stack22and the upper cover of the battery pack20. The supply air duct26extends toward the rear, while the width thereof gradually becomes narrower. This supply air duct26is connected to an air outlet28aaround the blower28. The blower28has a cylindrical shape and blows out air drawn in from a side intake port28bin a radial direction, and blows out air from the air outlet28aprovided in a portion of a donut-shaped blowing chamber.

The intake air duct60has a pipe-shape that extends from the front toward the rear, and the rear end of the intake air duct60is connected to the intake port28bof the blower28, as shown inFIG. 4C. The front end is a rectangular-shaped inlet62.

Next, the effects of the example embodiment will be described. In this way, with this example embodiment, the battery pack20is housed in the battery housing space10cbelow the seat cushion10aof the rear seat10, so the battery will not get in the way of other equipment and vehicle space is able to be more efficiently utilized. Also, the discharge port50aof the discharge duct48is provided right behind the back surface lower portion of the seatback10bof the rear seat10, so the discharge duct48is able to be relatively short, which enables pressure loss there to be small.

Furthermore, the exhaust port32opens into the discharge duct48, the discharge duct48discharges exhaust air from the discharge port50a, and the discharge port50ais pointed in a substantially horizontal direction and is covered by cloth or the like, so foreign matter is able to be prevented from getting in from the outside. In particular, the discharge port50ais offset from the exhaust port32in the width direction, so air discharged upward from the exhaust port32temporarily travels in the width direction of the vehicle, and then strikes the back surface of the seatback10bfrom the discharge port50ain the front surface and escapes upward. This kind of an air path makes it possible to reliably prevent foreign matter from getting in and the like. Also, the discharge port50ais provided over a relatively large area in the vehicle width direction, so pressure loss is able to be reduced with a relatively complex path.

Exhaust air is discharged into the luggage space40from the opening between the deck board42and the back surface of the seatback10b. Therefore, it is unlikely that this airflow will affect an occupant, so exhaust air will not cause the occupant any discomfort.

Also, the inlet62is on a side lower portion of the rear seat, so it is less likely that the flow of intake air from here will be felt by a leg of an occupant or the like. Moreover, the inlet62is pointed at an angle, so the flow of intake air is not that fast. As a result, the intake air will not easily be felt by an occupant, and noise generated by the intake air is also able to be suppressed.