JP2007165200A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack allowing its height and size to be reduced, and allowing the whole of a battery module to be evenly cooled. <P>SOLUTION: This battery pack includes: the battery module; an internal inlet duct for supplying a cooling medium introduced from a cooling medium introduction opening in the direction of the battery module; an internal discharge duct for discharging the cooling medium led out from the direction of the battery module from a cooling medium discharge opening; and an external inlet duct connected to the cooling medium introduction opening. The cross-sectional area of a surface vertical to the flowing direction of the cooling medium of a space for running the cooling medium in the external inlet duct is maximized between a connection surface of the external inlet duct to the cooling medium introduction opening and a predetermined position, and is further reduced on the upstream side; the cooling medium introduction opening and the cooling medium discharge opening are arranged on the same surface side of a housing; the cooling medium introduction opening guides the cooling medium passing through the cooling medium introduction opening in a first direction; and the internal inlet duct has a rectifying means for deflecting the cooling medium led out from a lead-out opening of the internal inlet duct in a second direction substantially perpendicular to the first direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a battery pack mounted on an electric vehicle or the like.

  In recent years, an electric vehicle using an electric motor as a drive source and a so-called hybrid electric vehicle combining an electric motor and another drive source have been put into practical use. In such a vehicle, a battery for supplying electric energy to the electric motor is mounted. As this battery, for example, a secondary battery such as a nickel cadmium battery, a nickel hydride battery, or a lithium ion battery that can be repeatedly charged and discharged is used.

  Usually, the secondary battery is configured as a battery module in which battery cells are stacked, and is mounted on a vehicle or the like in a state where the battery module is accommodated in a casing. In the present application, the casing, a housing component such as a battery module housed in the housing, and a component such as a piping component externally connected to the housing are collectively referred to as a battery pack.

  The battery module generates heat due to an internal electrochemical reaction, and its temperature rises. Since the power generation efficiency of the battery module decreases when the temperature rises, for example, cooling air or the like is introduced into the housing from the outside to cool the battery module.

  Various types of battery pack cooling structures using this cooling air have been proposed. For example, the battery module is accommodated in the housing in an inclined state in the longitudinal direction so that the refrigerant is uniformly supplied in the longitudinal direction of the battery module, and the cross-sectional area of the cooling air supply path to the battery cell is set upstream. A method has been proposed in which the pressure is lowered toward the downstream side (Patent Document 1).

In addition, the battery pack is required to have a low profile due to the mounting space when the battery pack is mounted on the vehicle. Therefore, normally, the intake fan and the exhaust fan of the battery pack are arranged so as to protrude from both side surfaces sandwiching the longitudinal direction of the battery module.
Japanese Unexamined Patent Publication No. 7-320794

  However, when the height of the battery pack is reduced by the above-described arrangement, the battery module intake fan and exhaust fan are arranged on the opposite side of the battery pack, so that the battery pack cannot be sufficiently downsized. There is a problem that it cannot be installed.

  As a countermeasure for this problem, it is conceivable to configure the cooling flow path of the battery pack so that the intake fan and the exhaust fan can be installed on the same side of the battery pack. It is necessary to deflect the flow of cooling air, and it is difficult to maintain a uniform flow of cooling air supplied to the battery module. Therefore, there exists a problem that temperature distribution arises in a battery module and favorable performance cannot be obtained.

  The present invention has been made in view of such problems, and it is possible to reduce the height and size of the battery pack and to provide a battery pack having a cooling structure capable of uniformly cooling the entire battery module. The issue is to provide.

  In order to solve the above problems, in the present invention, a battery module configured by stacking a plurality of cells in a casing and a refrigerant introduced into the casing through a refrigerant inlet are supplied in the direction of the battery module. An internal air intake duct, and an internal exhaust duct that discharges the refrigerant derived from the direction of the battery module to the outside of the housing through the refrigerant discharge port, and is connected to the refrigerant introduction port outside the housing. A battery pack having an external air intake duct, wherein a cross-sectional area of a surface perpendicular to a direction in which the refrigerant flows in a space in which the refrigerant flows in the external air intake duct is predetermined from a connection surface between the external air intake duct and the refrigerant introduction port. The refrigerant introduction port and the refrigerant discharge port are installed on the same surface side of the housing, and the refrigerant introduction port is the refrigerant introduction port. The refrigerant that passes through the first The internal intake duct has a rectifying means for deflecting the refrigerant derived from the outlet of the internal intake duct in a second direction substantially perpendicular to the first direction. A battery pack is provided.

  By defining the structure of the battery pack in this way, the battery pack can be reduced in height and size. In addition, since the shape of the external intake duct is determined as described above and the rectifying means is provided in the internal intake duct, the refrigerant introduced from the external intake duct is uniformly introduced into the rectifying means of the internal intake duct. Even if the flow of the refrigerant is deflected in the internal intake duct, turbulence or the like hardly occurs. Accordingly, the refrigerant can be supplied at a uniform flow rate throughout the battery module.

  The rectifying means is composed of a plurality of slits installed on the bottom or top surface of the internal intake duct, each of the plurality of slits having a respective opening at the outlet of the internal intake duct, Further, it may be installed along the second direction so as to partition the bottom or top surface of the internal air intake duct without any breaks. By configuring the shape of the rectifying means in this way, the above-described effects can be easily obtained.

  Here, it is preferable that the slit width and the installation interval in the first direction of the plurality of slits are constant. Thus, a suitable refrigerant supply structure to the battery module can be obtained without increasing the design parameters so much.

  Further, a closed portion where the refrigerant does not flow may be installed in the vicinity of the connection surface with the refrigerant introduction port inside the external intake duct.

  Further, the blocking portion is installed with a predetermined thickness (X) in contact with a part of the inner wall of the external intake duct along the flow direction of the refrigerant in the external intake duct, and the external intake duct and the refrigerant introduction You may comprise so that it may have a downstream edge part in predetermined distance (W) from the connection surface of an opening | mouth.

  Here, the distance (W) from the connection surface between the external intake duct and the refrigerant inlet to the downstream end of the closed portion is 1/2 or more of the total height (H) of the connection surface. Is preferred.

  Moreover, it is preferable that the thickness (X) of the blocking portion is ¼ or more of the total height (H) of the connection surface. By configuring the blocking portion in this way, the above-described effects of the present invention can be expressed more effectively.

  Furthermore, the first direction may be a direction substantially parallel to the cell stacking direction. Thereby, it becomes possible to cool each laminated battery cell more uniformly.

  In the battery pack of the present invention, since the introduction part of the refrigerant into the housing and the exhaust part are installed on the same side surface of the housing, the battery pack can be reduced in height and size. In addition, due to the aforementioned structure of the external intake duct and the internal intake duct, the refrigerant introduced from the external intake duct is uniformly supplied to the battery module via the internal intake duct, so that the entire battery module is uniformly cooled. Is possible.

  Embodiments based on the present invention will be described below.

  FIG. 1 shows an example of a mounting state of a battery pack in a vehicle according to the present embodiment.

  In FIG. 1, the battery pack 1 is mounted on the rear side of the rear seat 500 of the vehicle. However, it should be noted that the mounting location of the battery pack 1 is not particularly limited. As the refrigerant introduced into the battery pack 1, for example, cooling air by air in the vehicle compartment is used. The same side surface of the battery pack 1 includes an external intake duct 80 for guiding the air in the vehicle interior to the battery pack 1 and an external exhaust duct 90 for exhausting the cooling air introduced into the battery pack 1 to the outside. It is connected to.

  FIG. 2 is a block diagram when the vehicle 100 is driven by a battery system having a battery pack according to the present invention. The vehicle 100 includes a control unit 101, a battery unit 102 including a battery pack, and a drive unit 103. The control unit 101 is installed in a device box 30 (see FIG. 3) arranged inside the battery pack 1, and controls the battery 102 and the drive unit 103. The drive unit 103 may include an internal combustion engine such as a gasoline engine or a diesel engine in addition to an electric motor such as a motor driven by a current supplied from the battery unit 102. That is, the vehicle 100 includes not only an electric vehicle but also a hybrid car provided with a driving means other than an electric motor such as a gasoline engine.

  FIG. 3 is a perspective view of the battery pack of the present invention, and FIG. 4 is a schematic cross-sectional view taken along the line III-III of the battery pack shown in FIG. Note that the cooling structure of the battery pack 1 of this embodiment is a so-called upflow type in which the refrigerant flows from the bottom to the top in the battery module. In each figure, the white arrow indicates the flow of the refrigerant. In the following description, the case where this refrigerant is cooling air will be described as an example. However, it will be apparent to those skilled in the art that the refrigerant is not limited to this in the present invention.

  As shown in FIG. 3 and FIG. 4, the battery pack 1 includes a housing 2 composed of an upper case 3 and a lower case 4, a battery module 10 disposed inside the housing 2, an internal intake duct 8, and an internal An exhaust duct 9 and an equipment box 30 are provided. As defined above, the battery pack 1 further includes an external intake duct 80 connected through the internal intake duct 8 and the intake port 8a, and an external exhaust duct connected through the internal exhaust duct 9 and the exhaust port 9a. 90 (not shown).

  The housing 2 is configured by combining the upper case 3 and the lower case 4 and fastening the ends with bolts 33, and has a space inside.

  The battery module 10 is configured by stacking a plurality of battery cells 11 as shown in FIG. As the battery cell, for example, a secondary battery such as a nickel cadmium battery, a nickel hydrogen battery, or a lithium ion battery can be used. The battery cell 11 has a so-called square plate-like outer shape.

  Projections 11a are provided on the side surfaces of the individual battery cells 11 (both ends in the Y direction in FIG. 4), and the projections 11a extend to the side surfaces of the battery module 10 after the battery cells 11 are stacked. Parts. End plates 15 that maintain the stacked state of the battery modules 10 are disposed at both ends in the stacking direction (X direction) of the battery modules 10 (see FIG. 5). They are connected by a blanket 26 and a restraining belt 16 (see FIG. 4) that engage with protrusions formed on the side surfaces.

  Convex portions (not shown) are provided on the main surface (both end surfaces in the X direction) of each battery cell 11, and cooling air is circulated between the stacked battery cells 11 by this convex portion. A part of the passage (hereinafter referred to as “cooling passage”) is formed. In the present embodiment, the battery module 10 is installed so as to have a predetermined angle of inclination with respect to the bottom surface of the lower case 4 (inclination in the Y direction in FIG. 4). This is because the cooling air discharged from the internal intake duct 8 is uniformly supplied to the lower surface side of the battery module 10.

  The internal space of the housing 2 is partitioned by the battery module 10. An upper space is formed between the upper surface of the battery module 10 and the upper case 3, and the upper cooling flow path 5 is shaped by this upper space. Further, a lower space is formed between the lower surface of the battery module 10 and the lower case 4, and the lower cooling flow path 6 is shaped by this lower space. Therefore, the cooling channel is constituted by the space in which the upper cooling channel 5, the lower cooling channel 6 and the battery module 10 are installed (the cooling channel formed by the above-described convex portions). Between one of the side end surfaces (side end surfaces orthogonal to the Y direction) of the battery module 10 parallel to the stacking (X) direction of the cells 11 and the side surfaces of the upper case 3 and the bottom case 4 facing each other, the first Side space 7a is formed. Between the other of the side end surfaces (side end surfaces orthogonal to the Y direction) of the battery module 10 parallel to the stacking (X) direction of the cells 11 and the side surfaces of the upper case 3 and the bottom case 4 facing each other, Two side spaces 7b are formed.

  A gasket 23 is installed between the upper cooling flow path 5, the first side space 7a, and the second side space 7b, and airtightness between these spaces is ensured. Further, a gasket 23 is installed between the lower cooling flow path 6 and the first side space 7a and the second side space 7b, and the confidentiality between these spaces is ensured. For this gasket 23, for example, an independent foamed EPDM rubber or the like is used.

  An internal intake duct 8 and an internal exhaust duct 9 are installed in the first side space 7a and the second side space 7b located on the side surface side of the battery module 10, respectively. As shown in FIG. 3, an intake port 8a is provided on one surface of the housing so that cooling air is supplied in the longitudinal direction (X direction) of the internal intake duct 8, and the internal intake duct 8 It communicates with the mouth 8a. Further, an exhaust port 9a is provided on the same housing surface as the surface on which the intake port 8a is provided so that the cooling air is discharged in the longitudinal direction (X direction) of the internal exhaust duct 9, and the internal exhaust duct 9 Communicates with the exhaust port 9a. The internal intake duct 8 corresponds to a communication portion that connects the intake port 8a corresponding to the cooling air introduction port and the lower cooling channel 6 that is a part of the cooling channel. Similarly, the internal exhaust duct 9 corresponds to a communication portion that connects the exhaust port 9a corresponding to the cooling air outlet and the upper cooling channel 5 that is a part of the cooling channel.

  As described above, according to the battery pack 1 of the present invention, the introduction portion of the cooling air to the housing and the exhaust portion are installed on the same side surface of the housing, so that the battery pack can be reduced in height and size. .

  However, in such a battery pack cooling structure, after the cooling air is introduced into the internal intake duct 8, it is necessary to deflect the cooling air toward the battery module 10 (more precisely, the lower cooling flow path 6). In general, the deflection of the cooling air causes turbulence and eddy currents. In such a situation where the turbulent flow or vortex of the cooling air is generated, the cooling air introduced from the internal intake duct 8 through the lower cooling flow path 6 is not uniformly supplied to the battery module 10 side, and is locally supplied to the battery module. Temperature rise may occur. Such a local temperature rise of the battery module may deteriorate the battery performance and impair the reliability of the battery.

  Therefore, in the present invention, the cross-sectional area of the surface of the external intake duct 80 perpendicular to the direction in which the cooling air flows is the largest from the connection surface between the external intake duct 80 and the intake port 8a to a predetermined position, and further upstream. On the side, the external intake duct 80 is configured to be smaller. Further, rectifying means for deflecting the cooling air introduced from the intake port 8a is installed in the internal intake duct 8. As a result, when the cooling air introduced through the external intake duct 80 and the intake port 8a is deflected in the internal intake duct 8, generation of turbulence and vortex is effectively suppressed and deflected. It is possible to maintain a constant flow velocity when the cooled air is introduced from the internal intake duct 8 into the lower cooling flow path 6 in the stacking (X) direction of the cells 11. Therefore, in the battery pack of the present invention, uniform cooling air can be supplied to the entire battery module, and local temperature rise of the battery module can be suppressed.

  Hereinafter, the rectifying means provided in the internal intake duct 8 and the shape of the external intake duct 80 will be described with reference to specific examples. Note that the structure of the internal exhaust duct 9 is not particularly limited when the effects of the present invention are manifested. Therefore, the internal exhaust duct 9 may have a conventional structure.

  First, an example of rectifying means provided in the internal intake duct 8 will be described. FIG. 5 shows the positional relationship between the internal intake duct 8, the internal exhaust duct 9, and the battery module 10. FIG. 6 shows an enlarged perspective view of a portion surrounded by VI in FIG. The internal intake duct 8 has three surfaces perpendicular to the Y direction (first surface 8d1, second surface 8d2, and third surface 8d3 in order from the upstream side in the direction of cooling air flow along the Y direction, respectively). Have On the third surface 8d3 of the internal intake duct 8, openings corresponding to each of the plurality of slits 55 provided in the internal intake duct 8 are provided in a row. The plurality of slits 55 extend along the Y direction on the bottom surface of the internal intake duct 8 and extend from the third surface 8d3 to the first surface 8d1 of the internal intake duct 8 on the bottom surface of the internal intake duct 8. It is installed to partition. 5 and 6, the intervals between the slits 55 are shown at equal intervals, but the embodiment of the present invention is not limited to this, and the intervals between the slits 55 gradually decrease as the distance from the intake port increases. It may be set to. However, in order to avoid an increase in design parameters, it is preferable that the slit intervals are equal.

  By providing such a slit 55 as a rectification means in the internal intake duct 8, it becomes possible to significantly prevent the turbulence of the cooling air that occurs when the flow of the cooling air is deflected, and the rectified cooling air is The lower cooling flow path 6 can be supplied. This is because the cooling air is adjusted so as to have a parallel flow by each slit 55 before being led out from the outlet of the internal intake duct 8.

  However, it is difficult to keep the flow velocity of the cooling air flowing through each slit 55 constant only by installing a rectifying means such as a slit. This is because, generally, the slit closer to the intake port 8a tends to increase the flow velocity of the cooling air. In this case, as viewed from the flow of the cooling air along the X direction in FIG. 5, the battery module 10 is less likely to be cooled toward the downstream side.

  Here, generally, the flow velocity distribution of the cooling air flowing through the connection surface between the external intake duct 80 and the intake port 8a varies depending on the internal structure of the external intake duct 80. Therefore, in the present invention, the cooling air is uniformly introduced into the slits 55 of the internal intake duct 80 by controlling the flow velocity distribution of the cooling air on the connection surface. That is, the external intake duct 80 has the above-described structure, the flow velocity distribution of the cooling air flowing through the connection surface is adjusted, and the cooling air is uniformly introduced into the rectifying means of the internal intake duct 8, so that the internal intake duct 80 The flow velocity of the derived cooling air is made uniform with respect to the X direction of the battery module. Hereinafter, such an effect of the present invention will be described by taking an external intake duct 80 having a closed portion as an example as means for changing the internal sectional area. However, in order to exert the effects of the present invention, the external intake duct 80 does not necessarily have a closed portion, and the shape of the external intake duct 80 itself may be a structure that satisfies the above-described cross-sectional area state. It will be clear.

  FIG. 7 and FIG. 8 show a schematic cross-sectional view along the flow direction of the cooling air in the vicinity of a portion in contact with the intake port 8a of the conventional external intake duct 80, and a schematic cross-sectional view of the same portion according to the present invention, respectively. . In the case of the shape of the conventional external intake duct 80 of FIG. 7, the flow velocity of the cooling air flowing in the duct is maximized at the center of the duct and decreases as it approaches the inner wall of the duct. Accordingly, the flow velocity in the height direction of the cooling air flowing in the intake port 8a is roughly distributed as shown on the right side of FIG. 7 (hereinafter referred to as a non-linear distribution). In the cooling air passing through the intake port 8a in such a flow velocity distribution state, the flow velocity increases as the slit is closer to the intake port 8a as described above. Therefore, the flow rate of the cooling air derived from the outlet of the internal intake duct 8 is uneven with respect to the X direction. On the other hand, the external intake duct 80 of the present invention has a closed portion 85 where cooling air does not flow at a predetermined distance (W) from the joint surface with the intake port 8a. The height of the blocking portion 85 is X. When such a blocking portion is appropriately installed in the flow path, the flow velocity of the cooling air at the joint surface between the external intake duct 80 and the intake port 8a increases toward the upper side of the intake port 8a. That is, the flow velocity in the height direction of the cooling air flowing through the intake port 8a has a distribution as schematically shown on the right side of FIG. 8 (hereinafter referred to as a linear distribution). In such a flow velocity distribution, the cooling air passing through the intake port 8a is also close to the slit of the internal intake duct 8 located far from the intake port 8a (downstream side in the X direction) and close to the intake port 8a (upstream side in the X direction). ) Flows in the same manner as the slits in (), so that it becomes difficult for the cooling air led out from the outlet of the internal intake duct 8 to have a deviation in flow velocity. Accordingly, the cooling air is uniformly supplied from the internal intake duct 8 to the entire lower cooling flow path 6, and a local temperature rise of the battery module 11 can be suppressed.

  Here, it is preferable that the distance W from the joint surface of the closing portion 85 with the intake port 8a is 1/2 or more of the height H of the external intake duct 80. When the distance W is W <H / 2, the distance that the cooling air is affected by the step of the blocking portion 85 (the influence of the discontinuity of the cooling air flow passage cross-sectional area) is too short, so the external intake duct 80 and the intake port 8a This is because the flow velocity distribution of the cooling air at the joint surface is not a clear linear distribution, and the effects of the present invention cannot be sufficiently obtained. The height X of the closing portion 85 is preferably not less than 1/4 of the height H of the external intake duct 80. When the height X is X <H / 4, the cooling air is less affected by the blocking portion 85, and the flow velocity distribution of the cooling air at the joint surface between the external intake duct 80 and the intake port 8a becomes the conventional nonlinear distribution. This is to get closer.

  Thus, in the battery pack 1 of the present invention, the cooling air is deflected in the internal intake duct 8 even when the introduction portion of the cooling air to the housing 2 and the exhaust portion are installed on the same side surface of the housing 2. It is possible to suppress the disturbance of the cooling air that occurs when In addition, it becomes possible to suppress the deviation of the flow velocity of the cooling air derived from the outlet of the internal intake duct 8 in the X direction, so that the cooling air can be uniformly supplied from the internal intake duct 8 to the entire battery module 11. it can. Accordingly, the battery module 10 can be lowered in height, and the battery module 10 can be uniformly cooled, thereby suppressing a local temperature rise.

  In each of the above embodiments, the case where air in the vehicle compartment is used as the refrigerant of the battery pack 1 has been described as an example. However, other refrigerant gas or liquid may be used. These refrigerants may be circulated through a heat exchanger or the like.

  In the above description, the configuration in which the battery module 10 is inclined at a predetermined angle with respect to the bottom surface of the bottom case 4 in the upflow type cooling structure is shown as an example. However, the present invention is not limited to the cooling structure having such a structure. For example, by simply changing the positional relationship of the rectifying means with respect to the internal intake duct 8 and the position of the closed portion 85 of the external intake duct 80, for example, downflow The present invention can also be applied to a mold cooling structure or a structure in which the battery module 10 is arranged in parallel to the bottom surface of the bottom case 4. Furthermore, in the present invention, it should be noted that the internal intake duct, the battery module, and the internal exhaust duct may be configured in any arrangement relationship as long as the same effect can be obtained.

It is a figure which shows the mounting state to the vehicle of a battery pack. It is a block diagram in the case of driving a vehicle with a battery system having a battery pack according to the present invention. 1 is a schematic perspective view of a battery pack according to the present invention. FIG. 4 is a schematic cross-sectional view taken along line III-III in FIG. FIG. 3 is an exploded perspective view showing a positional relationship between an internal intake duct, an internal exhaust duct, and a battery module of the battery pack according to the present invention. FIG. 6 is an enlarged view of a portion surrounded by VI in FIG. It is a figure which shows the structure of the conventional external intake duct, and the flow velocity distribution of the cooling air which passes along the junction part of an external intake duct and an inlet port. It is a figure which shows the structure of the external intake duct of the Example of this invention, and the flow velocity distribution of the cooling air which passes along the junction part of an external intake duct and an inlet port.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery pack 2 Case 3 Upper case 4 Lower case 5 Upper cooling flow path 6 Lower cooling flow path 7a 1st side space 7b 2nd side space 8 Internal intake duct 8a Intake port 8d1 Y direction of internal intake duct 8d2 Second surface perpendicular to the Y direction of the internal intake duct 8d3 Third surface perpendicular to the Y direction of the internal intake duct 9 Internal exhaust duct 9a Exhaust port 10 Battery module 11 Cell 11a Projection 15 End plate 30 Equipment box 33 Bolt 55 Slit 80 External intake duct 85 Closed portion 90 External exhaust duct 100 Vehicle 101 Control unit 102 Battery unit 103 Drive unit 500 Rear seat.

Claims (8)

A battery module configured by stacking a plurality of cells in the housing, an internal intake duct for supplying the refrigerant introduced into the housing through the refrigerant inlet in the direction of the battery module, and from the direction of the battery module An internal exhaust duct for discharging the derived refrigerant to the outside of the housing through the refrigerant discharge port,
A battery pack having an external intake duct connected to the refrigerant introduction port outside the housing,
The cross-sectional area of the surface through which the refrigerant in the external intake duct flows is perpendicular to the direction in which the refrigerant flows, and is the largest from the connection surface between the external intake duct and the refrigerant inlet to a predetermined position, and further upstream. So it ’s getting smaller,
The refrigerant introduction port and the refrigerant discharge port are installed on the same surface side of the housing, the refrigerant introduction port guides the refrigerant passing through the refrigerant introduction port in a first direction,
The battery pack, wherein the internal intake duct has rectifying means for deflecting the refrigerant derived from the outlet of the internal intake duct in a second direction substantially perpendicular to the first direction. The rectifying means is composed of a plurality of slits installed on the bottom surface or top surface of the internal intake duct,
Each of the plurality of slits has a respective opening at the outlet of the internal air intake duct, and is installed so as to partition the bottom surface or the upper surface of the internal air intake duct substantially without being cut along the second direction. 2. The battery pack according to claim 1, wherein:   3. The battery pack according to claim 2, wherein a slit width and an installation interval in the first direction of the plurality of slits are constant.   The battery pack according to any one of the preceding claims, wherein a closed portion where no refrigerant flows is installed in the vicinity of a connection surface with the refrigerant introduction port inside the external intake duct.   The blocking portion is installed with a predetermined thickness (X) in a state in contact with a part of the inner wall of the external intake duct along a direction in which the refrigerant in the external intake duct flows, and the external intake duct and the refrigerant introduction port 5. The battery pack according to claim 4, further comprising a downstream end portion at a predetermined distance (W) from the connection surface.   The distance (W) from the connection surface between the external intake duct and the refrigerant introduction port to the downstream end of the closed portion is 1/2 or more of the total height (H) of the connection surface, The battery pack according to claim 5.   7. The battery pack according to claim 5, wherein the thickness (X) of the blocking portion is ¼ or more of the total height (H) of the connection surface.   The battery pack according to any one of the preceding claims, wherein the first direction is a direction substantially parallel to a cell stacking direction.

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