JP5434662B2 - Drainage structure for vehicle battery unit - Google Patents

Description

  The present invention relates to a drainage structure that discharges condensed water generated in association with cooling of a vehicle battery unit.

  In recent years, various types of eco-cars equipped with a power source other than an internal combustion engine (engine) have been developed in view of the magnitude of environmental load on the global environment. In an electric vehicle or a fuel cell vehicle, an electric motor or a motor generator driven by electric energy stored in a battery (secondary battery or capacitor such as a storage battery or a rechargeable battery) is used as a power source. Also, in hybrid cars and plug-in hybrid cars, an internal combustion engine and a motor generator are used in combination, for example, driving and charging a motor generator with power generated by the internal combustion engine, or using regenerative energy during deceleration. In addition to charging by an internal combustion engine and a motor generator, charging from an external power source has been proposed.

The battery mounted on the vehicle as described above generates Joule heat due to internal resistance and heat due to a chemical reaction inside the battery during charging and discharging. The amount of heat generated by the battery increases as the power consumption and the frequency of charging and discharging increase. On the other hand, in order to exhibit battery performance, it is desirable to keep the battery temperature within an appropriate operating range.
Therefore, a technique has been proposed in which the air cooled by the passenger compartment air conditioner is supplied to the battery to control the battery temperature. For example, it is known to provide a duct for introducing cool air blown from an air conditioner into a vehicle interior and a duct for introducing cool air to the battery side, and a switching damper is provided at a branching point of these ducts. By controlling the switching damper according to the temperature in the passenger compartment and the battery temperature, both the passenger compartment and the battery can be cooled, and appropriate temperature management can be realized.

  In addition, a technique is also known in which a cooling device dedicated to a battery is provided separately from the vehicle compartment air conditioner (for example, Patent Document 1). That is, a heat exchanger is disposed inside the battery case to cool the air, and this is supplied to the entire battery case by a blower. With this technique, it is said that the cooling efficiency of the battery can be improved.

JP 2008-54379 A

  By the way, since water droplets condense inside the cooling device and the surface of the heat exchanger, it is necessary to discharge them outside the vehicle. For example, in the technique of Patent Literature 1, the cooling device is attached to be inclined to the outside of the battery case, and a drainage drain is provided below the cooling device to discharge condensed water droplets to the outside of the battery case. That is, the internal space of the cooling device is opened to the outside through the drainage drain.

  Therefore, considering the layout with a large-capacity battery unit attached to the lower part of the vehicle floor, moisture and sludge enter the drainage drain to discharge condensed water when the vehicle travels in a flooded channel or mud. There is a fear. On the other hand, if the battery case and the cooling device are hermetically sealed, internal contamination due to moisture and sludge is prevented, but condensed water that is inevitably generated by cooling cannot be discharged.

Thus, in the conventional vehicle battery unit provided below the vehicle body floor, there is a problem that it is difficult to achieve both protection against moisture and sludge and drainage of condensed water.
One of the purposes of this case was created in view of such problems, and by improving the drainage of condensed water while ensuring moisture shielding against the lower side of the vehicle floor with a simple configuration. is there.

  The present invention is not limited to this purpose, and is a function and effect derived from each configuration shown in the embodiments for carrying out the invention described later, and other effects of the present invention are to obtain a function and effect that cannot be obtained by conventional techniques. Can be positioned.

The vehicle battery unit drainage structure disclosed herein includes a battery pack provided below the vehicle floor, a cooling unit that is built in the battery pack and includes a heat exchanger that cools the air inside the battery pack, A first drainage hole formed below the cooling unit and opened below the vehicle floor, and a first drainage hole formed below the first drainage hole at the bottom of the battery pack and opened below the vehicle floor. a secondary drainage holes, by water pressure from the lower side of said vehicle floor closes the said second drainage holes, comprising a closed chain means that to prevent water penetration from said first drain hole and said second drain hole, a, The first drain hole and the second drain hole are provided at positions overlapping in the vertical direction .

Further, the first drain hole is preferably formed through the bottom of the battery pack.
Also, the closed chain means, than the first drain hole and said second drain hole provided below the floating member for closing the lower end of the second drain hole with moves upward by receiving the buoyancy in water It is preferable to have .

Also, the closed chain means comprises a sensor for detecting the moisture in the vicinity of the first drainage hole and said second drain hole, when said moisture is detected by said sensor, said first drain hole and said second And a control valve for closing the drain hole .

In the disclosed drainage structure for a vehicle battery unit , the first drainage hole and the second drainage hole are provided at positions overlapping in the vertical direction. Also, closing the second water discharge hole by pressure from below the vehicle, it is closed chain means is provided that to prevent water penetration from the first drain hole and a second drain hole. Thus, it is possible to discharge the condensed water from the first drain hole and a second drain hole, and can control the opening and closing state of the first drain hole and a second drain hole at the same time, intrusion of moisture from the outside Can be prevented. That is, it is possible to improve the drainage of condensed water while ensuring the moisture shielding property on the lower side of the vehicle body floor, and to prevent internal cooling of the cooling unit.

It is a perspective view of the battery unit for vehicles provided with the drainage structure concerning one embodiment. It is a disassembled perspective view which shows the structure of the battery unit of FIG. It is a longitudinal cross-sectional view which shows typically the internal structure of the battery unit of FIG. 2, (a) shows the open state of a 1st drain hole, (b) shows a closed state. It is a perspective view which shows the closing valve of the battery unit of FIG. It is a longitudinal cross-sectional view which shows typically the internal structure of the battery unit for vehicles provided with the drainage structure as a 1st modification, (a) shows the open state of a 1st drainage hole, (b) shows a closed state. Show. It is a longitudinal cross-sectional view which shows typically the internal structure of the vehicle battery unit provided with the drainage structure as a 2nd modification, (a) shows the open state of a 1st drainage hole and a 2nd drainage hole, (b) Indicates a closed state. It is a vehicle battery unit provided with the drainage structure as a 3rd modification, Comprising: It is a figure which shows notionally the structure at the time of a cooling unit being provided in the exterior of a battery pack, (a) is draining to the cooling unit side A hole is provided, (b) is provided with a drain hole on the battery pack side, and (c) is provided with a drain hole on both the cooling unit and the battery pack.

Hereinafter, an embodiment of a drainage structure for a vehicle battery unit will be described with reference to the drawings. However, the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not clearly shown in the embodiment described below.
[1. overall structure]
FIG. 1 shows a battery unit 10 and a vehicle body frame 7 to which a drainage structure according to an embodiment is applied. The body frame 7 is a monocoque body sub-frame, and a pair of left and right side members 7a extending in the vehicle length direction (front-rear direction) of the vehicle, and a plurality of cross members 7b spanned between the left and right side members 7a in the vehicle width direction. And are provided. Here, the pair of side members 7a are spaced apart in the vehicle width direction, and the cross member 7b is spaced apart in the vehicle length direction.

  Both ends of the cross member 7b are fixed to the left and right side members 7a by welding to form a ladder-like structure. The battery unit 10 is fixed to the lower surface of the body frame 7 with fasteners such as bolts and nuts. The lower surface of the vehicle body frame 7 here is a lower part of a vehicle floor panel (hereinafter also referred to as a vehicle floor), for example, a portion that may be below the water surface when the vehicle travels in a puddle.

[2. Battery unit]
The battery unit 10 includes a battery pack 1 and a cooling unit 2 disposed therein.
The battery pack 1 is a highly rigid insulating case made of a reinforced resin, a reinforcing metal plate, or the like. The shape of the battery pack 1 is a flat shape extending in the horizontal direction, and the amount of protrusion downward from the body frame 7 is suppressed. Battery pack 1 is provided below the vehicle floor.

  As shown in FIG. 2, the battery pack 1 is divided into two parts in the vertical direction, and is composed of a lower battery tray 1a and an upper battery cover 1b. The battery tray 1a and the battery cover 1b are members molded in a container shape that is open at the top and bottom, respectively, and the opened surfaces are combined to face each other so that the internal space of the battery pack 1 can be combined. Form.

  A plurality of brackets 11 protrude in the horizontal direction on the side surface of the battery tray 1a (here, the left and right side surfaces of the vehicle). These brackets 11 are members for fastening and fixing the battery pack 1 to the vehicle body frame 7. In addition, a refrigerant piping hole 13 is drilled on the other side surface of the battery tray 1a (here, the side surface on the vehicle front side). The refrigerant pipe hole 13 is an opening through which a refrigerant pipe 2f connected to the cooling unit 2 described later is passed.

A duct 1c having a shape bulging upward is formed on the upper surface of the battery cover 1b. The duct 1c is a member that forms a passage for supplying air cooled by a cooling unit 2 described later to every corner of the battery pack 1. A fan 9 for blowing air is housed inside the battery pack 1 on the upper surface of the battery cover 1b.
A plurality of battery modules 8 and a cooling unit 2 are provided inside the battery pack 1. The battery modules 8 are arranged on the battery tray 1a at a predetermined interval. Each battery module 8 is connected to a wiring member (not shown), and power is supplied to an electric motor provided outside the battery pack 1.

The cooling unit 2 is disposed at a side end portion in the battery pack 1 and circulates while cooling the air inside the battery pack 1. The air cooled by the cooling unit 2 is pushed out by the fan 9, passes through the duct 1 c, cools the battery modules 8 while passing through the gaps between the battery modules 8, and is sucked into the cooling unit 2 again to be cooled. Is done.
2, the cooling unit 2 includes an evaporator 2a (heat exchanger), a cooling tray 2b, and a cooling cover 2c. The evaporator 2a is connected to a refrigerant pipe 2f that receives supply of refrigerant vaporized by an expansion valve (not shown). In the core 2e of the evaporator 2a, a plurality of fins through which the refrigerant flows are arranged in parallel at predetermined intervals, and the refrigerant flowing through the core 2e takes heat from the air passing between these fins. Cool the air.

  As shown in FIG. 3A, the cooling tray 2b and the cooling cover 2c are formed in a container shape having a size for accommodating the evaporator 2a therein. Moreover, the opening part 12 is provided in the side surface of the cooling unit 2 facing the core 2e of the evaporator 2a. Air inside the battery pack 1 is introduced into the cooling unit 2 through the opening 12 and passes through the core 2e of the evaporator 2a.

A fan duct 2d is connected to the top of the cooling cover 2c. The fan duct 2 d introduces cooled air to the fan 9 side, and is connected to the vicinity of the suction port of the fan 9. In addition, the flow of air is shown by the white arrow in Fig.3 (a).
A cylindrical first drain hole 3 is formed on the bottom surface 2g of the cooling tray 2b. A through hole 1g is also drilled in the bottom surface 1f of the battery tray 1a at a position overlapping the first drain hole 3 in a top view. The inner diameter of the through hole 1 g is formed larger than the outer diameter of the first drain hole 3.

  The first drain hole 3 is a hole opened below the vehicle floor so as to discharge water droplets condensed on the core 2e of the evaporator 2a and the inner wall of the cooling unit 2, and is provided at the lowest position of the bottom surface 2g. It is done. Here, as shown to Fig.3 (a), the bottom face 2g is formed in the funnel shape centering on the 1st drain hole 3. As shown in FIG. That is, the bottom surface 2g is inclined such that the position of the first drainage hole 3 is the lowest and becomes higher as the horizontal distance from the first drainage hole 3 increases.

  Moreover, the hole wall of the 1st drain hole 3 is formed so that it may extend below, and the lower end 3a has reached below rather than the bottom face 1f of the battery tray 1a. That is, the first drain hole 3 passes through the bottom surface 1f of the battery pack 1 and protrudes downward through the through hole 1g. Therefore, when water droplets generated in the cooling unit 2 fall to the bottom surface 2 g, the water droplets flow toward the first drain hole 3 and are discharged to the outside of the battery pack 1 through the inside of the first drain hole 3. The flow of water droplets is indicated by black arrows in FIG.

  An annular seal 1e is provided between the bottom surface 1f of the battery tray 1a and the bottom surface 2g of the cooling tray 2b so as to surround the through hole 1g. The seal 1e is an elastic member that is in close contact with both the bottom surfaces 1f and 2g. As a result, the gap between the outer side of the hole wall of the first drain hole 3 and the through hole 1g is sealed. A grommet 1d made of an elastic member is inserted into the refrigerant pipe hole 13 through which the refrigerant pipe 2f passes through the side surface of the battery cover 1b. Thereby, the airtightness of the internal space of the battery pack 1 and watertightness are ensured.

[3. Closing valve]
A closing valve 4 (first closing means) is loosely inserted into the first drain hole 3. That is, the closing valve 4 is provided so as to be movable in the vertical direction inside the first drain hole 3. As shown in FIG. 4, the shut-off valve 4 is a valve body formed of a lightweight resin or metal, and includes a shaft member 4a, a gap holding member 4b, and a floating member 4c.

  The shaft member 4 a is a shaft-like member provided so as to extend in the vertical direction through the inside of the first drain hole 3. The outer diameter of the shaft member 4 a is smaller than the inner diameter of the first drain hole 3, and a slight gap is formed between the shaft member 4 a and the hole wall of the first drain hole 3. The vertical length of the shaft member 4a is longer than the vertical dimension of the first drainage hole 3 (the depth of the hole, the dimension from the bottom surface 2g to the lower end 3a of the first drainage hole 3). It is formed. The gap holding member 4b is fixed to the upper end of the shaft member 4a, and the floating member 4c is fixed to the lower end.

  The gap holding member 4b is a disk-like member that spreads in the horizontal direction, and a plurality of protrusions 4d are formed on the lower surface thereof. These protrusions 4d are hemispherical portions that protrude downward from the surface of the gap holding member 4b, contact the bottom face 2g of the cooling tray 2b, and between the bottom face 2g and the lower face of the gap holding member 4b. A predetermined gap is formed. FIG. 4 illustrates an example in which the shaft member 4a, the gap holding member 4b, and the plurality of protrusions 4d are integrally formed.

  The floating member 4c is also a disk-shaped member spreading in the horizontal direction. The upper surface of the floating member 4 c contacts the lower end 3 a of the first drain hole 3 to close the first drain hole 3, and is at least larger than the inner diameter of the hole of the first drain hole 3. In FIG. 4, the floating member 4c is formed separately from the shaft member 4a, and is illustrated as being fixed to the shaft member 4a by an arbitrary fixing means such as a bolt or a screw screw.

  The mass of the shut-off valve 4 is heavy enough to receive upward buoyancy in water and move upward. Here, as shown in FIG. 3B, the weights of the shaft member 4a, the gap holding member 4b, and the floating member 4c are set so that the floating member 4c floats up to the water surface when the water is immersed. In addition, it is preferable to form the inside of the shaft member 4a, the gap holding member 4b, and the floating member 4c hollow.

[4. Action, effect]
As shown in FIG. 3A, during normal driving of the vehicle, the plurality of protrusions 4d come into contact with the bottom surface 2g of the cooling tray 2b due to the dead weight of the closing valve 4, and the gap between the bottom surface 2g and the gap holding member 4b is formed. Retained. That is, the internal space of the cooling unit 2 is always open to the outside of the battery pack 1. As a result, water droplets condensed on the surface of the evaporator 2 a and the inside of the cooling unit 2 are smoothly discharged to the outside of the battery pack 1 through the bottom surface 2 g and the inside of the first drain hole 3. On the other hand, when the vehicle travels on a submerged channel and the water surface approaches just below the battery pack 1, the floating member 4c receives the buoyancy and moves upward as shown in FIG. The lower end 3a is closed. That is, the shut-off valve 4 functions to prevent water intrusion from the first drain hole 3 by water pressure from below the vehicle floor.

As described above, by providing the shut-off valve 4 in the first drain hole 3, water droplets condensed in the cooling unit 2 can be discharged at all times, and when the water surface approaches just below the battery pack 1. It is possible to prevent moisture from entering the cooling unit 2 from the outside.
In addition, with a simple configuration in which the first drain hole 3 protrudes downward so as to penetrate the bottom surface 1f of the battery pack 1, water droplets discharged from the first drain hole 3 can be reliably discharged, and The first drain hole 3 can be closed at the lower surface than the battery pack 1.

Further, since the seal 1e is provided between the bottom surface 1f of the battery tray 1a and the bottom surface 2g of the cooling tray 2b so as to surround the through hole 1g, the water level is higher than the bottom surface 1f of the battery tray 1a. Even if it rises to the upper limit, moisture can be prevented from entering the battery pack 1.
Furthermore, the opening and closing of the first drain hole 3 can be controlled with a simple configuration in which the floating member 4c that moves upward in response to buoyancy is used, and the cost can be reduced. Further, since the vertical dimension (thickness) is not required for the floating member 4c, the protruding dimension from the bottom surface of the battery pack 1 on the lower surface of the vehicle body floor can be reduced, and the vehicle battery unit can be downsized. it can.

  Since the floating member 4c is formed separately from the shaft member 4a, the closing valve 4 can be easily attached to the first drain hole 3.

[5. Modifications etc.]
[5-1. First modification]
The internal structure of the battery unit for vehicles provided with the drainage structure as a 1st modification is shown to Fig.5 (a), (b). In addition, the same code | symbol is attached | subjected to the thing corresponding to each structure demonstrated by the above-mentioned embodiment, and description is abbreviate | omitted.

  As shown in FIG. 5A, in this modification, the shape of the first drain hole 3 and the closing valve 4 for closing the first drain hole 3 are different from those of the above-described embodiment. The hole wall of the first drain hole 3 has a diameter lower than the upper side to form a valve body chamber 4e containing a ball 4h as a valve body. The mass of the ball 4h is small enough to receive the buoyancy and move upward as in the above-described floating member 4c, and floats up to the water surface inside the valve body chamber 4e when flooded.

The upper surface 4f of the valve body chamber 4e has a triangular pyramid-shaped cavity, and its top communicates with the internal space of the cooling unit 2. A plurality of holes 4g are formed in the lower surface of the valve body chamber 4e so that the valve body chamber 4e communicates with the outside regardless of the position of the ball 4h in the valve body chamber 4e.
With such a configuration, for example, when the water surface reaches the inside of the valve body chamber 4e during traveling in a submerged channel, the ball 4h rises and contacts the upper surface 4f of the valve body chamber 4e as shown in FIG. 5B. Then, the first drain hole 3 is closed. On the other hand, as shown in FIG. 5A, when the water level is lowered, the ball 4h is moved downward in the valve body chamber 4e by its own weight, and the first drain hole 3 is opened.

  Therefore, also in this first modification, the same effect as in the above-described embodiment can be obtained, water droplets condensed in the cooling unit 2 can be always discharged, and the water surface is directly below the battery pack 1. In the case of approaching the water, it is possible to prevent moisture from entering the cooling unit 2 from the outside.

[5-2. Second modification]
The internal structure of the battery unit for vehicles provided with the drainage structure as a 2nd modification is shown to Fig.6 (a), (b). In addition, the same code | symbol is attached | subjected to the thing corresponding to each structure demonstrated by the above-mentioned embodiment, and description is abbreviate | omitted.

As shown to Fig.6 (a), in this modification, the 2nd drainage hole 5 is provided instead of the through hole 1g of the above-mentioned embodiment. The second drain hole 5 is formed in a cylindrical shape having a larger diameter than the first drain hole 3 and opens the internal space of the battery pack 1 to the lower side of the vehicle body floor. That is, here, the seal 1e of the above-described embodiment is omitted. The hole wall of the second drain hole 5 is formed to extend downward, and the lower end 5 a thereof is set lower than the lower end 3 a of the first drain hole 3. Therefore, the first drain hole 3 is disposed inside the cylindrical second drain hole 5 .

  With such a configuration, during normal driving of the vehicle, as shown in FIG. 6A, the plurality of protrusions 4d come into contact with the bottom surface 2g of the cooling tray 2b due to the dead weight of the shut-off valve 4, and the clearance from the bottom surface 2g is maintained. A gap with the member 4b is maintained. Therefore, the condensed water in the cooling unit 2 is discharged outside through the hole of the first drain hole 3. Even if condensation occurs on the inner wall or duct 1c of the battery pack 1 cooled by the cold air blown out from the cooling unit 2, the water droplets travel along the bottom surface 1f of the battery tray 1a and enter the hole of the second drain hole 5. And discharged to the outside.

  On the other hand, when the vehicle travels on a submerged channel or the like and the water surface approaches just below the battery pack 1, the floating member 4c receives the buoyancy and moves upward as shown in FIG. 6B, and the upper surface of the floating member 4c. Closes the lower end 5 a of the second drain hole 5. Since the first drain hole 3 is located inside the closed battery pack 1, the first drain hole 3 is also closed at the same time. Accordingly, moisture can be prevented from entering the battery pack 1 and the cooling unit 2.

As described above, in the second modified example, in addition to the effects of the above-described embodiment, the condensed water in the battery pack 1 can be discharged to the outside, and the intrusion of moisture from the outside can be prevented. .
Further, in the battery pack 1 incorporating the cooling unit 2, the first drain hole 3 and the second drain hole 3 and the second drain hole 5 are overlapped by a simple configuration in which the position of the first drain hole 3 and the position of the second drain hole 5 are overlapped. The open / close state of the two drain holes 5 can be controlled simultaneously. That is, since only one means for preventing water from entering the battery pack 1 and the cooling unit 2 is required, the cost can be reduced.

Incidentally, the lower end 3a of the first drainage hole 3 to set to be positioned lower end 5a of the second drain hole 5 downward, for example, the upper surface of the buoy member 4c is for horizontal plane. That is, the height and end face shape of the lower end 3a of the first drain hole 3 and the lower end 5a of the second drain hole 5 can be arbitrarily set according to the shape of the upper surface of the floating member 4c. At least, by contacting the upper surface of the float member 4c on the entire lower end 5 a of the second drain hole 5 can be closed substantially to the first drainage hole 3 and a second drain hole 5 at the same time.

[5-3. Third modification]
A drainage structure when the cooling unit 2 of the above-described embodiment is arranged outside the battery pack 1 will be described with reference to FIGS. When the battery pack 1 and the cooling unit 2 are individually provided below the vehicle body floor, the following two types of moisture to be discharged outside the vehicle can be considered.
(i) Moisture condensed in the cooling unit 2
(ii) Moisture condensed in the battery pack 1

  In view of the fact that the air inside the battery pack 1 and the cooling unit 2 circulates in the almost closed space, the amount of condensation in the duct 1c and the battery pack 1 cooled by the cold air from the cooling unit 2 is If the amount is expected to be very small, it may be possible to use a drainage structure corresponding only to the above (i). On the other hand, if importance is attached to the drainage of water in the battery pack 1 even in a very small amount, it is necessary to use only the above (ii) or a drainage structure corresponding to the above (i) and (ii). Conceivable. These drainage structures can be appropriately selected according to the installation height of the battery pack 1 and the cooling unit 2, the required drainage performance, the expected condensed water content, the manufacturing cost of the battery pack 1 and the cooling unit 2, and the like.

  The example shown in FIG. 7A is a drainage structure corresponding to the above (i). Here, a shut-off valve 4 is interposed in the first drain hole 3 formed in the bottom surface 2g of the cooling tray 2b. Therefore, when the water surface approaches immediately below the cooling tray 2b, the first drain hole 3 is closed, and moisture can be prevented from entering the cooling unit 2 from the outside. On the other hand, the opening opened downward is not formed in the bottom face 1f of the battery tray 1a. Therefore, even if the water surface approaches just below the battery pack 1, moisture does not enter the battery pack 1.

  The example shown in FIG. 7B is a drainage structure corresponding to the above (ii). Here, a second closing valve 6 (second closing means) is interposed in the second drain hole 5 formed in the bottom surface 1f of the battery tray 1a. The second closing valve 6 is a valve body having a configuration similar to that of the closing valve 4, moves upward due to buoyancy, and closes the second drain hole 5. Therefore, when the water surface approaches immediately below the battery pack 1, the second drain hole 5 is closed, and moisture can be prevented from entering the battery pack 1 from the outside. On the other hand, the opening part opened downward is not formed in the bottom face 2g of the cooling tray 2b. Therefore, even if the water surface approaches immediately below the cooling unit 2, moisture does not enter the cooling unit 2.

  The example shown in FIG. 7C is a drainage structure corresponding to both the above (i) and (ii). In this case, it is possible to discharge all the moisture condensed inside the battery pack 1 and the cooling unit 2 and to prevent moisture from entering from the outside.

[6. Others]
Regardless of one example and modification of the embodiment described above, various modifications can be made without departing from the spirit of the invention. Each composition of this embodiment and a modification can be chosen as needed, or may be combined suitably.

  In the above-described embodiment and modification, the one using the closing valve 4 using buoyancy is illustrated, but instead of or in addition to such a configuration, the discharge hole may be closed by electronic control. Good. For example, in the configuration shown in FIG. 3A, when a moisture sensor for detecting moisture is provided near the through hole 1g or near the lower end 3a of the first drain hole 3, and moisture is detected by this moisture sensor. It is conceivable to provide an electronic control valve for closing the first drain hole 3. With such a configuration, flexible control according to the running state of the vehicle is possible. For example, the first drain hole 3 can be closed not only when the vehicle is submerged but also when the water rebounds frequently from the road surface, and the internal submersion of the cooling unit 2 can be more reliably prevented.

In addition, the specific structure of the closing valve 4 is not limited to the thing of embodiment and a modification. At least the water pressure from the lower part of the vehicle floor may prevent water intrusion from the first drain hole 3. For example, the closing valve 4 itself such as a valve structure using a member having elasticity or flexibility is vertically moved. Includes structures that do not move.
Moreover, in the above-mentioned embodiment and modification, although the 1st drainage hole 3 and the 2nd drainage hole 5 illustrated what was formed in the bottom face of the cooling unit 2 or the battery pack 1, these drainage holes are not necessarily in the bottom face. There is no need to provide it. It suffices to be provided at least in the lower part of the cooling unit 2 or the battery pack 1, and may be a position where the internal moisture is discharged to the outside.

  Moreover, although the structure which attaches the battery pack 1 to the sub-frame of a monocoque body was shown in the above-mentioned embodiment, application to the vehicle which has vehicle body structures other than a monocoque body is also possible, for example with respect to a ladder frame structure The battery pack 1 may be fixed. At least, it can be applied to all vehicles in which the battery pack 1 and the cooling unit 2 are provided below the vehicle floor.

DESCRIPTION OF SYMBOLS 1 Battery pack 1a Battery tray 1b Battery cover 1c Duct 1d Grommet 1e Seal 1f Bottom face 1g Through hole 2 Cooling unit 2a Evaporator (heat exchanger)
2b Cooling tray 2c Cooling cover 2d Fan duct 2e Core 2f Refrigerant piping 2g Bottom surface 3 First drain hole 3a Lower end 4 Shut-off valve (first closing means)
4a Shaft member 4b Gap holding member 4c Floating member 4d Protrusion 4e Valve body chamber 4f Upper surface 4g Hole 4h Ball 5 Second drain hole 5a Lower end 6 Second closing valve (second closing means)
7 Body frame 7a Side member 7b Cross member 8 Battery module 9 Fan 10 Battery unit 11 Bracket 12 Opening 13 Refrigerant piping hole

Claims (4)

A battery pack provided below the vehicle floor;
A cooling unit built in the battery pack and having a heat exchanger for cooling the air inside the battery pack;
A first drain hole formed in a lower portion of the cooling unit and opened below the vehicle floor;
A second drainage hole formed below the first drainage hole in the lower part of the battery pack and opened below the vehicle floor;
Closing said second drain hole by pressure from below the said vehicle floor, comprising a closed chain means that to prevent water penetration from said first drain hole and said second drain hole, a,
A drainage structure for a vehicle battery unit, wherein the first drainage hole and the second drainage hole are provided at positions overlapping in the vertical direction . Drainage structure of the first drainage holes, characterized in that it is formed through the lower portion of the battery pack, the vehicle battery unit according to claim 1, wherein. The closed chain means,
Than the first drain hole and said second drain hole provided below, and having a float member which closes the lower end of the second drain hole with moves upward by receiving the buoyancy in water, wherein Item 3. A drainage structure for a vehicle battery unit according to item 1 or 2. The closed chain means,
A sensor for detecting moisture in the vicinity of the first drain hole and the second drain hole ;
The control valve according to any one of claims 1 to 3, further comprising a control valve that closes the first drain hole and the second drain hole when the moisture is detected by the sensor. The drainage structure of the vehicle battery unit.

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