JP4791076B2 - Battery box cooling structure - Google Patents

Description

  The present invention relates to a cooling structure for a battery box mounted on an electric vehicle such as a hybrid vehicle or an electric vehicle.

Conventionally, as a cooling structure of the battery box in the electric vehicle, in order to suppress the temperature variation of the battery module and maintain its power generation performance well, the cooling performance is improved by forming a turn flow in which the cooling air reciprocates in the battery box. There is one that increases the flow velocity on the downstream side where the temperature of the cooling air is likely to increase by increasing the flow rate (see, for example, Patent Documents 1 to 3) or by narrowing the cross-sectional area on the downstream side of the cooling air flow channel (for example, Patent References 3 and 4).
JP 2002-31440 A JP 2000-301954 A JP-A-8-310256 JP-A-10-255859

However, even if the above-described configuration is adopted, there may be a variation in the temperature of the battery module due to a rise in the cooling air temperature on the downstream side with respect to the upstream side of the cooling air flow path.
In particular, in a battery box that accommodates a plurality of long battery modules in combination with a plurality of battery cells in parallel at predetermined intervals, cooling air is supplied from the direction orthogonal to the longitudinal direction of the battery modules to cool them. In such a case, since the battery module has a long shape, the cross-sectional area of the cooling air flow path is large and it is difficult to sufficiently increase the flow velocity of the cooling air, and each battery is caused by an increase in the cooling air temperature on the downstream side. Since it becomes easy for the temperature variation of a module to arise, the improvement of such a point is desired.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to further suppress the temperature variation of each battery module in a battery box cooling structure in which a plurality of long battery modules are accommodated in parallel.

  As a means for solving the above-mentioned problems, the invention described in claim 1 is directed to an elongated battery module (for example, the battery module 22 of the embodiment) in which a plurality of battery cells (for example, the battery cell 36 of the embodiment) are combined. A cooling air flow path (for example, the cooling air flow path 30 of the embodiment) is arranged inside a battery box (for example, the battery boxes 20 and 50 of the embodiment) that is accommodated in parallel at intervals so as to cross the longitudinal direction of the battery module. A partition member (for example, the holders 25 and 56 of the embodiment) for partitioning the internal space of the battery box, and the partition member takes in the cooling air into the battery box (for example, the intake port 24 of the embodiment). And an exhaust port (for example, the exhaust port 2 of the embodiment) that discharges the cooling air to the outside of the battery box. In the cooling structure of the battery box that forms a return path (for example, the return path 32 of the embodiment) that leads to the exhaust path, the cross-sectional area on the exhaust port side in the cooling air flow path is smaller than the cross-sectional area on the exhaust port side. In addition to providing a partition member, the partition member is provided with a bypass hole (for example, bypass holes 35 and 57 in the embodiment) that connects the forward path and the return path.

According to this configuration, the cooling air taken into the battery box from the air inlet first enters the forward path, and flows downstream while passing through the portions facing the forward path of each battery module. Then, it turns back in the turn chamber in the battery box, enters the return path, flows between the parts facing the return path of each battery module and flows to the downstream side while cooling them, and then flows from the exhaust port to the outside of the battery box. To be discharged.
At this time, by providing a long battery module so as to straddle the forward path and the return path that form the cooling air turn flow, the temperature variation between the forward path and the return path due to the heat conduction of the battery module itself Is suppressed.

Also, by making the cross-sectional area on the exhaust port side smaller than the cross-sectional area on the intake port side of the cooling air flow path, the flow velocity on the exhaust air side (downstream side) of the cooling air increases, and the temperature rises due to heat absorption from the battery module Even with the cooled cooling air, the battery module on the exhaust port side is cooled well.
Moreover, by providing a bypass hole in the partition member between the forward path and the return path, the cooling air at the relatively low temperature on the forward path side is taken into the return path side at a relatively high flow rate, and the battery module on the exhaust port side is even better. To be cooled.

The invention described in claim 2 is characterized in that a cross-sectional area of the cooling air flow path formed in the battery box decreases from the upstream side to the downstream side.
According to this configuration, it is possible to maintain a good flow rate by gradually reducing the cross-sectional area of the cooling air flow path, and to improve the cooling performance of the battery module.

The invention described in claim 3 is characterized in that the partition member is formed of a holder for holding the battery module.
According to this configuration, it is not necessary to provide a dedicated partition member by effectively using the holder that holds the battery module, and the number of parts of the battery box can be suppressed.

The invention described in claim 4 is characterized in that a plurality of the bypass holes are formed in the partition member and are reduced in size from the upstream side to the downstream side in the forward path.
According to this configuration, since the temperature difference of the cooling air between the forward path and the backward path is relatively small on the downstream side of the forward path (the upstream side of the backward path), the upstream side of the forward path (the downstream side of the backward path) becomes the downstream side of the forward path. By reducing the size of the bypass hole, it is possible to maintain a good turn flow of the cooling air while promoting equalization of the cooling air temperature to suppress uneven cooling of the battery module.

  According to the present invention, a cooling air turn flow is formed in the battery box, and the elongated battery module is provided so as to straddle the forward path and the return path, so that the temperature of the battery module is made uniform by heat conduction. Can be achieved. In addition, the downstream area of the cooling air flow passage is reduced, and a bypass hole is provided in the partition member between the forward path and the return path, so that the relatively cool cooling air upstream of the forward path can be Therefore, the battery module temperature can be made more uniform.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the directions such as front, rear, left and right in the following description are the same as those in the vehicle unless otherwise specified. In the figure, the arrow FR indicates the front, the arrow LH indicates the left, and the arrow UP indicates the upward.

In FIG. 1, reference numeral 1 denotes a so-called parallel type hybrid vehicle (electric vehicle).
An engine 3, which is an internal combustion engine, a motor generator 4, and a transmission 5 are arranged in series in the engine room 2 at the front of the vehicle body of the hybrid vehicle 1. The motor generator 4 can be driven by supplying power from the battery box 20 in the trunk room 10 at the rear of the vehicle body, and the driving force of the motor generator 4 and the engine 3 is transmitted to the front wheels 6 as drive wheels via the transmission 5. Is possible. Further, when the hybrid vehicle 1 cruises or decelerates, the driving force of the engine 3 and the front wheels 6 is transmitted to the motor generator 4, and the battery generator 20 can be charged by functioning the motor generator 4 as a generator. It is.

Front and rear seats 8 and 9 are disposed in a vehicle compartment 7 behind the engine room 2, and a trunk room 10 is continuously provided behind the rear seat 9 via a partition or the like.
Referring also to FIG. 2, the battery box 20 is arranged in the trunk room 10 on the floor 11 immediately behind the rear seat 9 in a state of being fixed to a cross member of the vehicle body. The battery box 20 is formed by housing a plurality of battery modules 22 in a box-shaped case 21, and has a cooling fan 23 for circulating cooling air for cooling the battery modules 22 into the case 21. By operating the cooling fan 23, the air in the passenger compartment 7 can be sucked into the case 21 from the air inlet 24 that opens toward the space under the rear seat 9 in the case 21. A configuration in which a duct or the like is separately connected to the air inlet 24 may be used.

  The cooling air after flowing through the case 21 is discharged to the trunk room 10 or the outside of the vehicle after being used for cooling a device such as an inverter through a duct or the like as necessary. In the figure, reference numeral 2 denotes a spare tire accommodated in the recess 13 of the floor 11, and reference numeral 14 denotes a rear wheel 15 that bulges into the trunk room 10 on both rear sides of the rear seat 9 (both sides of the battery box 20) (see FIG. 1). ) Wheel house.

  As shown in FIGS. 3 to 5, each battery module 22 is formed in a long bar shape with a circular cross section, and these are arranged in parallel with the left and right direction (vehicle width direction), and on the pair of left and right holders 25 and the holding frame 26. It is accommodated in the case 21 in a held state. A predetermined gap is formed between the battery modules 22, and the entire surface of each battery module 22 is cooled by passing cooling air through the gap.

  The cooling air is sucked into the case 21 from the air inlet 24 on the right side of the front end of the case 21 and flows backward, and then turns back through the turn chamber 27 at the rear part in the case 21 and flows forward. It is discharged out of the case 21 through the exhaust port 28 on the left side of the front end. The flow of the cooling air at this time is indicated by a chain line arrow in FIG. The opening area of the exhaust port 28 is made smaller than the opening area of the intake port 24. A cooling fan 23 is attached to the exhaust port 28, and a turn flow in which the cooling air is turned back as described above is formed by the operation of the cooling fan 23. Hereinafter, a portion in front of the turn chamber 27 in the case 21 is referred to as a battery housing chamber 29.

  Each holder 25 is a plate-like one arranged so as to be substantially orthogonal to the longitudinal direction (left-right direction) of the battery module 22, and holds each battery module 22 in a state of passing through the battery module 22. The battery housing chamber 29 is divided into three regions in the left-right direction. Among these regions, the right and center regions are used as a forward passage 31 serving as a cooling air flow passage 30 through which cooling air is circulated from the intake port 24 opened to the front end thereof to the turn chamber 27, and the left region is a turn chamber. Similarly, a return path 32 is provided as a cooling air flow path 30 through which the cooling air flows from 27 to an exhaust port 28 opened at the front end of the region. The forward path 31 is wider than the return path 32, and thus the cross-sectional area of the return path 32 is smaller than the cross-sectional area of the forward path 31. Here, the left holder 25 of the holders 25 functions as a partition member that partitions the forward path 31 and the return path 32.

The cooling fan 23 is a centrifugal fan having a suction port 33 in the direction of the rotation axis and a blowout port 34 in a tangential direction around the rotation axis, the rotation axis being substantially parallel to the front-rear direction, and the suction port 33 being a case 21 in a state of being directly connected to the exhaust port 28 of the engine 21. If the suction port 33 is connected to the exhaust port 28 via a duct or the like, the layout flexibility of the cooling fan 23 and the battery box 20 can be increased.
As a result, the negative pressure can be reduced to the downstream side of the return path 32, and the cooling air can be sent well to the stagnation portion between the battery modules 22 on the downstream side of the return path 32. Moreover, the cooling property of the battery module 22 is further improved by sucking the lower air in the passenger compartment 7 that is less affected by the outside air temperature. Moreover, the exhaust from the battery box 20 is discharged outside the trunk room 10 or the vehicle, thereby suppressing the influence on the temperature inside the vehicle compartment 7.
At this time, as will be described in detail later, by providing a bypass hole 35 that communicates the upstream side of the forward path 31 (intake port 24 side) and the downstream side of the return path 32 (exhaust port side), cold cooling of the upstream side of the forward path 31 is performed. The wind can be sent to the stagnation point downstream of the return path 32. The cooling fan 23 may be attached to the intake port 24 of the case 21 or disposed in the turn chamber 27.

  Here, the battery box 20 is provided so as to gradually narrow the cross-sectional area of the cooling air flow path 30 from the upstream side toward the downstream side by changing the vertical width of the case 21 and each holder 25. Specifically, the part constituting the upper and lower walls of the forward path 31 in the case 21 is provided so as to narrow the vertical width of the forward path 31 from the upstream side toward the downstream side, and the part constituting the upper and lower walls of the return path 32 is Similarly, the upper and lower widths of the return path 32 are provided so as to narrow from the upstream side toward the downstream side. Further, in order to align with the upper and lower walls of such a case 21, each holder 25 is also provided so as to change its vertical width. In this embodiment, the left holder 25 is orthogonal to the longitudinal direction of the battery module 22, but it is possible to further reduce the cross-sectional area of the cooling air passage 30 by inclining the holder 25 in a top view. .

Further, here, a plurality of (two in FIG. 3) bypass holes 35 communicating with the forward path 31 and the return path 32 are provided in a portion of the holder 25 near the intake port 24 in, for example, the front-rear direction (the flow direction of the cooling air). Provided side by side. Each bypass hole 35 is located at a position where the upstream side of the forward path 31 (intake port 24 side) and the downstream side of the return path 32 (exhaust port 28 side) communicate with each other, and the air at the lowest temperature in the cooling air flow path 30 has the highest temperature. Therefore, the battery module 22 downstream of the return path 32 can be effectively cooled.
Further, the downstream side of the return path 32 has another battery module 22 located on the upstream side, so that it is difficult for the cooling air to come into contact with it, and stagnation is likely to occur. Thus, the battery module 22 on the downstream side of the return path 32 can be more effectively cooled. Here, the bypass hole 35 positioned on the downstream side of the forward path 31 (upstream side of the return path 32) is provided so as to be reduced with respect to the bypass hole positioned on the upstream side of the forward path 31 (downstream side of the return path 32).

  As shown in FIG. 6, the battery module 22 is formed by electrically and structurally connecting a plurality of cylindrical battery cells 36 in series, and in FIG. The negative electrodes are arranged in reverse, and the end portions thereof are connected by an end plate 37. Reference numeral 38 in the figure denotes a spacer that is sandwiched between the battery modules 22.

  Eight such battery modules 22 are arranged at substantially equal intervals in the upper, middle, and lower stages of the battery box 20 (see FIGS. 4 and 5). At this time, the battery modules 22 are stacked in a staggered manner in a side view so as to effectively use the arrangement space. Each of these battery modules 22 is connected by a bus bar plate 39 (see FIG. 3) attached to both side ends thereof to constitute an integrated high voltage battery.

  The battery module 22 is configured to enhance the heat conduction between the battery cells 36 in order to enhance the heat conduction in the longitudinal direction. That is, in the battery module 22 in which the outer cylindrical members of the battery cells 36 are connected by welding, the distance between the battery cells 36 is minimized, the number of welding points and the number of welds are increased so as to increase the heat conduction at the connection portion of the battery cells 36. The area is increased, the thickness of the connection member between the battery cells 36 is increased, or the material is changed. Such a configuration is also preferable from the viewpoint of reducing internal resistance at the battery cell 36 connection portion. Further, a heat pipe may be attached to the battery module 22 in order to further increase the heat conduction. At this time, a member connected to the temperature detection element of the battery module 22 may also be used for heat conduction, or the member itself may be formed into a heat pipe.

  Here, each holder 25 is made of an insulating resin, and is divided into four parts of an upper holder 41, a second holder 42, a third holder 43, and a lower holder 44 in order from the top in the vertical direction as shown in FIGS. The Each of the holders 41 to 44 is divided by a substantially horizontal dividing surface positioned at the center height of the upper, middle, and lower battery modules 22. Are provided with a semicircular alignment portion 45 that matches the outer periphery of each battery module 22 (see FIG. 8). By sandwiching the battery modules 22 with the holders 41 to 44, the battery modules 22 are held in a state where the battery modules 22 are positioned.

  As shown in FIGS. 7 and 8, the bypass hole 35 formed in the left holder 25 uses a gap formed by partially cutting the abutting portion 46 on the dividing surface of each holder 41 to 44. With such a configuration, the parts cost of the holder 25 is reduced. Of course, a configuration in which the bypass hole 35 is formed in the holder 25 may be used.

FIG. 9 is a graph showing the temperature of the battery module 22 on the vertical axis and the temperature measurement position on the cooling air flow path 30 of the battery module 22 on the horizontal axis.
In FIG. 9, when the temperature change of the battery module 22 when the bypass hole 35 of the holder 25 is provided is a line a, and the temperature change when the battery module 22 is not provided is a line b, these are compared, from the upstream side of the forward path 31 to the upstream side of the return path 32 Although the temperature of the battery module 22 changes substantially regardless of the presence or absence of the bypass hole 35, when the bypass hole 35 is provided, the bypass hole 35 is provided in the return path 32 as compared with the case where the bypass hole 35 is not provided. The temperature of the battery module 22 is lower on the downstream side than the portion.

  Further, the temperature change of the battery module 22 when the heat conduction is not performed between the forward path 31 side and the return path 32 side of the battery module 22 due to, for example, the battery module 22 being divided at the holder 25 is shown as a line. c, and when compared with the lines a and b where the heat conduction is performed, when the heat conduction is not performed, the battery module after the upstream side of the forward path 31 is compared with the case where the heat conduction is performed. The temperature change of 22 becomes large. That is, the temperature variation of the battery module 22 is also suppressed by conducting heat conduction of the battery module 22 itself. Here, if the flow velocity on the downstream side of the cooling air is further increased by arranging the holder 25 or changing the shape of the case 21, it is possible to further suppress the temperature variation of the battery module 22. In addition, the line d in a figure shows the temperature change of the battery module 22 at the time of making this flow only in one direction, without forming the turn flow of cooling air in the battery box 20. FIG.

  As described above, the cooling structure of the battery box 20 in the embodiment described above is inside the battery box 20 that accommodates a plurality of long battery modules 22 in combination with a plurality of battery cells 36 in parallel at an arbitrary interval. The battery module 22 includes a holder 25 as a partition member that is arranged so as to intersect with the longitudinal direction of the battery module 22 and partitions the internal space of the battery box 20 to form the cooling air flow path 30. And a return path 32 connected to the exhaust port 28 for discharging the cooling air to the outside of the battery box 20, and a cross-sectional area of the cooling air channel 30 on the side of the intake port 24 The holder 25 is provided so that the cross-sectional area on the exhaust port 28 side becomes smaller than that of the outlet 25 and the forward path 3 When is provided with a bypass hole 35 connecting the return path 32.

According to this configuration, the cooling air taken into the battery box 20 from the air inlet 24 first enters the forward path 31 and cools them while passing between the parts facing the forward path 31 of each battery module 22. However, after flowing in the downstream side of the battery box 20, it turns back into the return path 32, enters the return path 32 of each battery module 22, passes through the portions facing the return path 32, and cools them downstream. After flowing, it is discharged out of the battery box 20 through the exhaust port 28.
At this time, by providing the battery module 22 having an elongated shape so as to straddle the forward path 31 and the backward path 32 forming the turn flow of the cooling air, the forward path 31 side and the backward path 32 side due to the heat conduction of the battery module 22 itself. Temperature variation between the two is suppressed.

Further, by reducing the cross-sectional area on the exhaust port 28 side from the cross-sectional area on the intake port 24 side of the cooling air flow path 30, the flow velocity of the cooling air on the exhaust port 28 side (downstream side) increases, Even with the cooling air whose temperature has increased due to heat absorption, the battery module 22 on the exhaust port 28 side is well cooled.
That is, the flow rate of the cooling air can be easily adjusted by controlling the flow path cross-sectional area using the holder 25 which is a partition member between the forward path 31 and the return path 32. Without being affected by the arrangement of the battery modules 22 and the like, the battery modules 22 can be evenly cooled to suppress temperature variations.

In addition, by providing the bypass hole 35 in the holder 25 between the forward path 31 and the return path 32, the cooling air on the relatively low temperature forward path 31 side is introduced into the return path 32 side having a relatively high flow velocity, and the exhaust port 28 side. The battery module 22 is cooled more satisfactorily.
That is, the temperature variation of the battery module 22 can be further suppressed by utilizing the fact that the temperature variation distributions of the forward path 31 and the backward path 32 are opposite to each other.

Further, in the cooling structure, the cross-sectional area of the cooling air flow path 30 formed in the battery box 20 becomes smaller from the upstream side to the downstream side.
According to this configuration, it is possible to maintain a good flow rate by gradually reducing the cross-sectional area of the cooling air flow path 30 and to improve the cooling performance of the battery module 22.

Further, in the cooling structure, a partition member for the forward path 31 and the backward path 32 is formed by a holder 25 that holds the battery module 22.
According to this configuration, it is not necessary to provide a dedicated partition member by effectively using the holder 25 that holds the battery module 22, and the number of parts of the battery box 20 can be suppressed.

Further, in the cooling structure, a plurality of bypass holes 35 are formed in the holder 25 and are reduced in size from the upstream side to the downstream side in the forward path 31.
According to this configuration, since the temperature difference of the cooling air between the forward path 31 and the backward path 32 is relatively small on the downstream side of the forward path 31 (upstream side of the backward path 32), the outbound path from the upstream side of the forward path 31 (downstream side of the backward path 32). 31 By reducing the bypass hole 35 toward the downstream side, it is possible to favorably maintain the turn flow of the cooling air while facilitating equalization of the cooling air temperature and suppressing the uneven cooling of the battery module 22.

Next, a second embodiment of the present invention will be described.
The battery box 50 in this embodiment does not change the vertical width of the case 21 and each holder 25 with respect to the battery box 20 of the first embodiment, and is a left-side holder that is a partition member between the forward path 31 and the return path 32 The main difference is that the cross-sectional area of the cooling air flow passage 30 is gradually narrowed from the upstream side to the downstream side and the layout of the cooling fan 23 is changed. The parts corresponding to one embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIGS. 10 and 11, the cooling fan 23 is disposed on the left side of the turn chamber 27 with the rotation axis thereof being substantially parallel to the left-right direction. At this time, the outlet 34 is directed to the inlet of the return path 32 and the suction port 33 is directed to the right side of the turn chamber 27 (outward path 31 side). When such a cooling fan 23 is activated, the entire turn chamber 27 is negative. The cooling air is uniformly distributed in the wide forward path 31 as a pressure, and the cooling air sucked by the cooling fan 23 is turned 90 degrees and then directly discharged toward the return path 32. The flow of the cooling air at this time is indicated by a chain line arrow in FIG.

  Thereby, the pressure loss of the cooling air in the turn chamber 27 is greatly reduced, and the heat transfer of the battery module 22 is promoted by the turbulent flow accompanying the dynamic pressure on the blowing side, and the cooling performance in the return path 32 is improved and the battery is improved. The temperature variation of the module 22 is suppressed. In addition, the cooling fan 23 moves away from the air inlet 24 that opens into the vehicle compartment 7, and noise in the vehicle compartment 7 associated with the operation is reduced. Moreover, the cooling property of the battery module 22 is further improved by sucking the lower air in the passenger compartment 7 that is less affected by the outside air temperature. In addition, the exhaust from the battery box 50 is discharged outside the trunk room 10 or the vehicle, thereby suppressing the influence on the temperature inside the vehicle compartment 7.

  Here, the left holder 25 has a cross-sectional area of the return path 32 so that the cross-sectional area of the forward path 31 gradually decreases from the upstream side (the intake port 24 side) toward the downstream side (the turn chamber 27 side). Inclined in top view with respect to the right holder 25 orthogonal to the longitudinal direction of the battery module 22 so as to gradually decrease from the upstream side (turn chamber 27 side) to the downstream side (exhaust port 28 side). It is done.

  Also in the second embodiment, similarly to the first embodiment, a cooling air turn flow is formed in the battery box 50 and the elongated battery module 22 is provided so as to straddle the forward path 31 and the return path 32. Thus, the temperature can be made uniform by the heat conduction of the battery module 22. In addition, the cross-sectional area of the cooling air flow path 30 is reduced toward the downstream side, and a bypass hole 35 is provided in the holder 25 between the forward path 31 and the return path 32, so that the relatively low temperature cooling air upstream of the forward path 31 is returned to the return path 32. The battery module 22 can be directly fed to the relatively high temperature battery module 22 on the downstream side, and the temperature of the battery module 22 can be made more uniform.

  The present invention is not limited to the above-described embodiments. For example, as shown in FIGS. 12 and 13, an insulating resin or rubber grommet 55 is integrally provided on the outer periphery of the battery module 22, and the grommet 55 is attached to the battery module. The holder 56 corresponding to the holder 25 may be configured by stacking together with the holder 22. At this time, a bypass hole 57 corresponding to the bypass hole 35 may be formed using a gap formed by cutting a part of the grommet 55.

In addition, the cooling air is circulated twice or more in the battery boxes 20 and 50 and a turn flow is formed so that the cooling air passes through the surface of the same battery module 22 twice or more. The temperature variation of the battery module 22 that occurs between the upstream side and the downstream side can be further suppressed. Here, the battery module 22 may be configured not to be parallel to the left-right direction, but to be parallel to the front-rear direction, for example.
The configuration in each of the above embodiments is an example of the present invention, and is not limited to application to a hybrid vehicle. Needless to say, various modifications can be made without departing from the gist of the present invention. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. It is side explanatory drawing which shows the principal part of the said hybrid vehicle. It is upper surface explanatory drawing of the battery box of the said hybrid vehicle. It is side explanatory drawing which looked at the said battery box from the left side. It is side explanatory drawing which looked at the said battery box from the right side. It is a perspective view which shows the one side of the battery module in the said battery box. It is a side view which shows the principal part of the holder of the said battery box. It is a perspective view of the components which constitute the holder. It is a graph which shows the temperature change of the battery module in the said battery box. It is upper surface explanatory drawing of the battery box in 2nd Example of this invention. It is side surface explanatory drawing of the battery box of FIG. It is a side view which shows the modification of the holder of each said battery box. It is a perspective view of the holder of FIG.

Explanation of symbols

20, 50 Battery box 22 Battery module 24 Air inlet 25, 56 Holder (partition member)
28 Exhaust port 30 Cooling air flow path 31 Outward path 32 Return path 35, 57 Bypass hole

Claims (4)

A battery that is disposed inside a battery box that accommodates a plurality of long battery modules in combination with a plurality of battery cells in parallel at an arbitrary interval so as to intersect with the longitudinal direction of the battery module to form a cooling air flow path. A partition member for partitioning the internal space of the box is formed, and the partition member forms an outward path connected to an intake port for taking cooling air into the battery box and a return path connected to an exhaust port for discharging the cooling air outside the battery box. In the cooling structure of the battery box,
The partition member is provided so that the cross-sectional area on the exhaust port side is smaller than the cross-sectional area on the intake port side in the cooling air flow path, and a bypass hole is provided in the partition member to connect the forward path and the return path. The battery box cooling structure. 2. The cooling structure of the battery box according to claim 1, wherein a cross-sectional area of the cooling air flow path formed in the battery box decreases from the upstream side to the downstream side. The battery box cooling structure according to claim 1, wherein the partition member is formed of a holder that holds the battery module. 4. The cooling of the battery box according to claim 1, wherein a plurality of the bypass holes are formed in the partition member, and are reduced as they go from the upstream side to the downstream side in the forward path. Construction.

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