JP7632003B2 - Battery Cooling Device - Google Patents

Description

This disclosure relates to a liquid-cooled battery cooling device that uses a refrigerant liquid.

Patent Document 1 discloses an electricity storage device equipped with a cooling body that cools a plurality of battery cells (i.e., batteries). The cooling body has a refrigerant flow path through which a refrigerant (e.g., cooling water) flows. The discharge pipe and the supply pipe are provided integrally with the cooling body and communicate with the refrigerant flow path.

JP 2020-145046 A

In the configuration described in Patent Document 1, if air gets into the cooling body from the supply piping, problems such as a decrease in the heat dissipation performance of the cooling body can occur due to reasons such as an increase in the thermal resistance value of the cooling body. For this reason, it is necessary to quickly separate the air that has flowed into the cooling body together with the refrigerant liquid from the cooling liquid and discharge it outside the cooling body, thereby reducing the amount of air circulating inside the cooling body together with the refrigerant liquid.

This disclosure was made in consideration of the above-mentioned problems, and aims to provide a battery cooling device that uses a simple structure to quickly separate air that has flowed into the cooling body together with the refrigerant liquid from the cooling liquid and discharge it outside the cooling body.

A battery cooling device according to the present disclosure includes a refrigerant circulation circuit through which a refrigerant liquid circulates, a pump, and a cooling body. The pump is disposed on the refrigerant circulation circuit and circulates the refrigerant liquid. The cooling body is disposed on the refrigerant circulation circuit and cools the battery. The cooling body includes a supply port, a discharge port, an internal refrigerant passage, and a short-circuit passage.
Refrigerant liquid flows into the supply port. The discharge port is disposed vertically above the supply port on the same plane as the supply port, and discharges the refrigerant liquid. The internal refrigerant passage includes an outward path through which the refrigerant liquid flowing in from the supply port flows, a return path through which the refrigerant liquid flows toward the discharge port after passing through the outward path and being reversed, and a first partition wall located between the supply port and the discharge port in the vertical direction and dividing the internal space of the cooling body into the outward path and the return path. The short-circuit passage has one or more through holes penetrating the first partition wall, and short-circuits the supply port and the discharge port.
The one or more through holes are provided in the first partition wall at a position closer to the end of the outward path and the return path on the supply port side than to the end on the turn-back portion side, and have a cross-sectional area smaller than the cross-sectional area of the outward path.

The one or more through holes may be formed at the end of the first partition on the supply port side.

The internal refrigerant passage may include a guide wall that is disposed in the forward path so as to face the flow of the refrigerant liquid flowing in from the supply port, and that guides the air that flows in from the supply port together with the refrigerant liquid so that it flows vertically upward.

The supply port and the discharge port may be arranged so as to overlap when viewed vertically. The one or more through holes may include a through hole arranged so as to be aligned on the same straight line as the supply port and the discharge port when viewed vertically.

The cooling body may include a first and a second internal space obtained by dividing the internal space of the cooling body by a second partition wall, and may have a combination of the supply port, the discharge port, the internal refrigerant passage, and the short-circuit passage for each of the first and second internal spaces. The flow direction of the outward passage of the internal refrigerant passage on the first internal space side may be opposed to the flow direction of the outward passage of the internal refrigerant passage on the second internal space side via the second partition wall.

According to the battery cooling device of the present disclosure, air that has entered the cooling body from the supply port together with the refrigerant liquid can be discharged from the discharge port by utilizing a short-circuit passage that short-circuits between the supply port and the discharge port. Therefore, the fluid passing through the forward and return paths of the internal refrigerant passage becomes refrigerant liquid from which the air has been well separated. In addition, since the cross-sectional area of the through hole is smaller than that of the forward path, short-circuiting of the refrigerant liquid due to the presence of the short-circuit passage can be suppressed. As described above, according to the battery cooling device of the present disclosure, it is possible to quickly separate the air that has flowed into the cooling body together with the refrigerant liquid from the cooling liquid and discharge it outside the cooling body by utilizing a simple structure.

1 is a schematic diagram showing an example of the configuration of a battery cooling device according to a first embodiment; 2 is a diagram for explaining the internal structure of a cooling body (tank portion) shown in FIG. 1 . FIG. 3 is a diagram showing the configuration around the tank shown in FIG. 2 as viewed from the vertical direction. FIG. 4 is a graph for explaining the effect on the heat dissipation performance of the cooling body obtained by the battery cooling device of embodiment 1. 11A and 11B are diagrams for explaining the configuration of a cooling body according to a second embodiment. 13A to 13C are diagrams for explaining the configuration of a cooling body according to embodiment 3. 13 is a graph for explaining the effect on the heat dissipation performance of the cooling body obtained by the battery cooling device of embodiment 3.

In each embodiment described below, elements common to each figure are given the same reference numerals, and duplicate explanations are omitted or simplified. Furthermore, when the number, quantity, amount, range, etc. of each element is mentioned in the embodiments described below, the technical idea of this disclosure is not limited to the mentioned number, unless otherwise specified or clearly specified in principle. Furthermore, the structures, etc. described in the embodiments described below are not necessarily essential to the technical idea of this disclosure, unless otherwise specified or clearly specified in principle.

1. First embodiment
1-1. Example of a configuration of a battery cooling device Fig. 1 is a schematic diagram showing an example of a configuration of a battery cooling device 10 according to the first embodiment. The battery cooling device 10 shown in Fig. 1 is configured to cool a battery module 1. The battery module 1 is an assembly of a plurality of battery cells, and corresponds to an example of a "battery" according to the present disclosure. The battery cooling device 10 is typically housed in a battery pack housing together with the battery module 1. The battery pack is mounted on an electric vehicle and supplies power to an electric motor for driving the vehicle.

The battery cooling device 10 includes a refrigerant circulation circuit 12 for circulating a refrigerant liquid. The refrigerant liquid is, for example, a cooling liquid with high insulating performance (i.e., high resistance). A specific example of the refrigerant liquid is an insulating LLC (long life coolant). In the refrigerant circulation circuit 12, a gas-liquid separation tank 14, a pump 16, and a cooling body 18 are arranged in this order, for example.

The gas-liquid separation tank (in other words, reserve tank) 14 stores the refrigerant liquid circulating in the refrigerant circulation circuit 12. The water inlet provided on the top surface of the gas-liquid separation tank 14 is closed by a cap 14a except when water is being poured. The gas-liquid separation tank 14 also has an inlet 14b and an outlet 14c for the refrigerant liquid. The internal space of the gas-liquid separation tank 14 constitutes part of the refrigerant circulation circuit 12. To make it difficult for air at the top of the gas-liquid separation tank 14 to be discharged from the outlet 14c, the outlet 14c is positioned vertically below the inlet 14b.

The pump 16 is, for example, electrically driven, and circulates the refrigerant liquid within the refrigerant circulation circuit 12. Specifically, when the pump 16 operates, the refrigerant liquid in the gas-liquid separation tank 14 is supplied to the cooling body 18. The refrigerant liquid that has passed through the cooling body 18 returns to the gas-liquid separation tank 14. The pump is controlled by an electronic control unit (ECU), not shown.

The cooling body 18 has a tank portion 20, which is an internal space in which the refrigerant liquid circulates. The specific configuration of the tank portion 20 will be described later with reference to Figures 2 and 3. In order to cool the battery module 1, the cooling body 18 is disposed, for example, on the underside of the battery module 1. However, the positional relationship between the battery module 1 and the cooling body 18 is not particularly limited. In addition, the cooling body 18 may have a battery contact surface that is in direct contact with the battery module 1, or a thermally conductive material may be interposed between the cooling body 18 and the battery module 1.

According to the above-described battery cooling device 10, heat generated in the battery module 1 is released to the refrigerant liquid via the cooling body 18. In other words, the battery module 1 is indirectly cooled by the refrigerant liquid via the cooling body 18. Note that the refrigerant circulation circuit 12 may be provided with a radiator for cooling the refrigerant liquid.

Here, there is a possibility that air may be mixed into the refrigerant liquid supplied to the cooling body 18. Specifically, for example, air may be mixed in by remaining in the refrigerant circulation circuit 12 when the refrigerant liquid is filled into the refrigerant circulation circuit 12. Also, for example, when high front-to-rear or left-to-right G forces act on the battery cooling device 10 while the vehicle is running, the liquid level in the gas-liquid separation tank 14 may tilt, and air may be supplied from the gas-liquid separation tank 14 to the cooling body 18.

When air gets mixed into the cooling body 18, the proportion of air bubbles (air bubble rate) contained in the refrigerant liquid increases, and the thermal resistance value of the cooling body 18 rises. Furthermore, the mixing of air leads to a decrease in the heat dissipation area of the cooling body 18. For these reasons, problems may occur such as a decrease in the heat dissipation performance of the cooling body 18 and an increase in the temperature of the refrigerant liquid.

To address the above problem, it is necessary to quickly separate the air that has flowed into the cooling body 18 together with the refrigerant liquid from the cooling liquid and discharge it outside the cooling body 18, thereby reducing the amount of air circulating inside the cooling body 18 together with the refrigerant liquid. In consideration of these issues, the cooling body 18 of this embodiment is configured as described below.

Figure 2 is a diagram for explaining the internal structure of the cooling body 18 (tank portion 20) shown in Figure 1. The tank portion 20, in which the refrigerant liquid circulates inside the cooling body 18, typically has a substantially rectangular parallelepiped shape. The cooling body 18 has a supply port 22 through which the refrigerant liquid flows in and a discharge port 24 through which the refrigerant liquid is discharged. More specifically, the supply port 22 and the discharge port 24 are inlets and outlets for the refrigerant liquid to the tank portion 20. The discharge port 24 is disposed vertically above the supply port 22 on the same plane as the supply port 22 (on the surface of the tank portion 20 including the tank outline 20a in Figure 2). In addition, Figure 2 is a diagram of the tank portion 20 viewed from a direction perpendicular to the flow direction of the refrigerant liquid passing through the supply port 22 and the discharge port 24 and the vertical direction.

The cooling body 18 further includes an internal refrigerant passage 26 and a short-circuit passage 28. The internal space of the tank portion 20 is used as the internal refrigerant passage 26. The internal refrigerant passage 26 constitutes part of the refrigerant circulation circuit 12.

Specifically, the internal refrigerant passage 26 includes an outward path 26a through which the refrigerant liquid flowing from the supply port 22 flows, a return path 26b through which the refrigerant liquid that has passed through the outward path 26a flows inverted toward the discharge port 24, and a partition wall 26c. The partition wall 26c is located between the supply port 22 and the discharge port 24 in the vertical direction, and is formed to divide the internal space of the cooling body 18 (tank portion 20) into the outward path 26a and the return path 26b. The partition wall 26c is formed to extend in the horizontal direction. In other words, as shown in FIG. 2, the internal refrigerant passage 26 has a U-turn shape. The thin lines around the arrows indicating the flow of the refrigerant liquid in FIG. 2 indicate the flow lines of the refrigerant liquid. The partition wall 26c corresponds to an example of a "first partition wall" according to the present disclosure.

The short-circuit passage 28 has a through hole 30 penetrating the partition wall 26c, and short-circuits the supply port 22 and the discharge port 24. The through hole 30 is provided in the partition wall 26c at a position closer to the end 26f on the supply port 22 side than the end 26e on the side of the folded portion 26d of the forward path 26a and the return path 26b. More specifically, in the example shown in FIG. 2, the through hole 30 is formed in the end 26g on the supply port 22 side of the partition wall 26c (in other words, near the end 26f). The through hole 30 has a cross-sectional area smaller than the cross-sectional area of the forward path 26a.

Figure 3 is a vertical view of the configuration around the tank section 20 shown in Figure 2. As shown in Figure 3, the supply port 22 and the discharge port 24 are arranged to overlap when viewed vertically, as an example. The through hole 30 is arranged to be aligned on the same straight line L as the supply port 22 and the discharge port 24 when viewed vertically. In addition, although there is one through hole 30 in the example shown in Figure 3, there may be multiple through holes. In an example in which there are multiple through holes 30, the multiple through holes 30 may all be arranged on the same straight line L, or may include through holes that are not on the same straight line L. The through hole 30 is, for example, circular, but its shape is not particularly limited.

1-2. Effects and Effects Air that has entered the cooling body 18 (tank portion 20) from the supply port 22 rises vertically upward due to buoyancy. In the absence of the short-circuit passage 28, the outward path 26a and the return path 26b are separated by a partition (corresponding to the partition 26c without the through-hole 30). For this reason, a portion of the air flows through the outward path 26a and the return path 26b together with the refrigerant liquid and is then discharged from the discharge port 24, while the remainder of the air remains in the tank portion 20 (for example, near the partition on the outward path 26a side and near the upper wall of the tank portion 20).

In contrast, in the cooling body 18 having the short-circuit passage 28, most of the mixed air rises due to buoyancy and heads toward the exhaust port 24 together with the cooling liquid that flows through the return path 26b after passing through the through hole 30. The air is then discharged from the exhaust port 24 together with the surrounding refrigerant liquid. That is, most of the mixed air does not head toward the folded portion 26d, but is discharged through the short-circuit passage 28 that short-circuits the supply port 22 and the exhaust port 24. Therefore, the fluid that passes through the forward path 26a and the return path 26b via the folded portion 26d becomes refrigerant liquid from which the air has been well separated. That is, the amount of air circulating through the forward path 26a and the return path 26b, which are the flow paths of the refrigerant liquid for cooling the battery module 1, is reduced. In addition, since the cross-sectional area of the through hole 30 is smaller than that of the forward path 26a, the short-circuiting of the refrigerant liquid due to the presence of the short-circuit passage 28 can be suppressed.

As described above, the battery cooling device 10 of this embodiment uses a simple structure to quickly separate the air that has flowed into the cooling body 18 together with the refrigerant liquid from the cooling liquid and discharge it to the outside of the cooling body 18. As a result, the amount of air circulating through the forward path 26a and the return path 26b, which are the flow paths of the refrigerant liquid, is reduced (in other words, the above-mentioned reduction in the bubble rate), which leads to the resolution of the above-mentioned problem.

Figure 4 is a graph for explaining the effect of the heat dissipation performance of the cooling body 18 obtained by the battery cooling device 10 of embodiment 1. The cooling body position, which is the horizontal axis of Figure 4, corresponds to the horizontal position of the tank section 20 shown in Figure 3, as indicated by positions P1 and P2. The solid waveform in Figure 4 corresponds to the battery cooling device 10 equipped with the short-circuit path 28, and the dashed waveform in the same figure corresponds to the comparative example not equipped with the short-circuit path 28.

As mentioned above, the inclusion of air leads to a decrease in heat dissipation performance. In the comparative example (dashed line), the air that flows into the tank part of the cooling body is likely to remain at each position in the tank part (especially near the folded part) due to the resistance of the flow of the refrigerant liquid in the tank part. This leads to an increase in the difference (variation) in the battery temperature (temperature of the battery module 1) according to the cooling body position, as shown by the dashed line in FIG. 4. In contrast, in the present embodiment (solid line) equipped with the short-circuit passage 28, the heat dissipation performance is locally decreased near the short-circuit passage 28 through which the air passes (near position P1), and the battery temperature rises. However, when viewed as a whole, the tank part 20 has an effect of suppressing the decrease in heat dissipation performance due to the inclusion of air, and the temperature rise of the refrigerant liquid is suppressed by suppressing the inclusion of air. In particular, the decrease in heat dissipation performance is well suppressed near the folded part 26d (near position P2), and the temperature rise of the refrigerant liquid is suppressed. Furthermore, the difference (variation) in battery temperature between the vicinity of the short-circuit passage 28 and the vicinity of the folded-back portion 26d is reduced more satisfactorily than in the comparative example.

As shown in FIG. 2, in the battery cooling device 10 of this embodiment, the through hole 30 is formed in the end 26g (in other words, near the end 26f) of the partition 26c on the supply port 22 side. This allows the air to be effectively short-circuited between immediately after the supply port 22 and immediately before the exhaust port 24 in the tank section 20.

Furthermore, in the battery cooling device 10, as shown in FIG. 3, the supply port 22 and the exhaust port 24 are arranged so as to overlap when viewed vertically. The through hole 30 is arranged so as to be aligned on the same straight line L as the supply port 22 and the exhaust port 24 when viewed vertically. Unlike this example, the supply port 22 and the exhaust port 24 do not necessarily have to overlap when viewed vertically, and the through hole 30 does not have to be aligned on the same straight line L as the supply port 22 and the exhaust port 24. In addition, by adopting the configuration shown in FIG. 3, it is possible to configure the short-circuit passage 28 to be shorter than the example in which the through hole 30, the supply port 22, and the exhaust port 24 are not aligned on the same straight line L when viewed vertically. Then, a configuration is obtained in which the air that flows in from the supply port 22 and then rises vertically upward can be quickly passed through the through path 30 and guided to the exhaust port 24.

2. Second embodiment
5 is a diagram for explaining the configuration of a cooling body 40 according to embodiment 2. An internal refrigerant passage 42 included in the cooling body 40 of this embodiment is configured similarly to the internal refrigerant passage 26 according to embodiment 1, except that it includes a guide wall 44.

As shown in FIG. 5, the guide wall (in other words, the baffle plate) 44 is disposed in the outward path 26a so as to face the flow of the refrigerant liquid flowing in from the supply port 22. The guide wall 44 is disposed and formed so as to be able to guide the air that flows in together with the refrigerant liquid from the supply port 22 so that it flows vertically upward.

More specifically, in order to realize the above-mentioned function, the guide wall 44 is provided, for example, at a position equivalent to the through hole 30 in the flow direction of the refrigerant liquid in the outward passage 26a (direction from the right side to the left side of the paper in FIG. 5). However, the position of the guide wall 44 in the flow direction may be any position that can realize the above-mentioned function, and may be upstream or downstream of the through hole 30. In addition, the guide wall 44 is formed, for example, in a plate shape in which the flow direction is the thickness direction. The opposing surface of the guide wall 44 that faces the flow of the refrigerant liquid from the supply port 22 has, for example, the same size as the supply port 22. In addition, the guide wall 44 is fixed to the wall of the cooling body 40 in the depth direction of the paper in FIG. 5 via, for example, an attachment member (not shown).

According to the cooling body 40 having the guide wall 44 described above, the refrigerant liquid containing air immediately after flowing in from the supply port 22 can be made to hit the guide wall 44, thereby encouraging the air to flow vertically upward. Therefore, the air that has flowed in together with the refrigerant liquid from the supply port 22 can be shunted to the exhaust port 24 via the shunt passage 46 more reliably than in the cooling body 40 of embodiment 1 that does not have the guide wall 44.

3. Third embodiment
6 is a diagram for explaining the configuration of a cooling body 50 according to embodiment 3. An internal space 52 of the cooling body 50 (more specifically, an internal space of a tank portion of the cooling body 50) is divided into a first internal space 52a and a second internal space 52b by a partition wall 54. More specifically, the first internal space 52a and the second internal space 52b are arranged horizontally with the partition wall 54 interposed therebetween. The partition wall 54 corresponds to an example of a "second partition wall" according to the present disclosure.

The cooling body 50 has a combination of the "supply port," "exhaust port," "internal refrigerant passage," and "short-circuit passage" according to the present disclosure for each of the first internal space 52a and the second internal space 52b. Specifically, the supply port 22, the exhaust port 24, the internal refrigerant passage 56, and the short-circuit passage 58 are arranged on the first internal space 52a side, and the supply port 22, the exhaust port 24, the internal refrigerant passage 60, and the short-circuit passage 62 are arranged on the second internal space 52b side.

The internal refrigerant passage 56 on the first internal space 52a side has an outward passage 56a and a return passage 56b partitioned by a partition wall 56c. The internal refrigerant passage 60 on the second internal space 52b side has an outward passage 60a and a return passage 60b partitioned by a partition wall 60c. A through hole 30 is formed in each of these partition walls 56c and 60c. In addition, as shown in FIG. 6, the flow direction of the outward passage 56a on the first internal space 52a side faces the flow direction of the outward passage 60a on the second internal space 52b side via the partition wall 54. In this way, the cooling body 50 has two U-turn shaped internal refrigerant passages 56 and 60 that face each other.

In addition, the configuration of the refrigerant circulation circuit 64 for circulating the refrigerant liquid in the pair of internal refrigerant passages 56 and 60 shown in FIG. 6 is not particularly limited. The refrigerant circulation circuit 64 may be configured, for example, so that the cooling liquid passes from the supply port 22 on the first internal space 52a side through the internal refrigerant passage 56 and exits from the discharge port 24, then passes from the supply port 22 on the second internal space 52b side through the internal refrigerant passage 60 and exits from the discharge port 24. Alternatively, the refrigerant circulation circuit 64 may be configured, for example, so that it branches into two on the upstream side of the cooling body 50, and the refrigerant liquid is supplied from the supply ports 22 of both the first internal space 52a and the second internal space 52b to the internal refrigerant passages 56 and 60, respectively, and then merges after being discharged from both discharge ports 24.

The battery cooling device of embodiment 3, which is equipped with the cooling body 50 configured as described above, can also utilize a simple structure to quickly separate the air that has flowed into the cooling body 50 (internal spaces 52a and 52b) together with the refrigerant liquid from the cooling liquid and discharge it outside the cooling body 50.

Figure 7 is a graph for explaining the effect on the heat dissipation performance of the cooling body 50 obtained by the battery cooling device of embodiment 3. The cooling body position on the horizontal axis of Figure 7 corresponds to the horizontal positions of the internal space 52 shown in Figure 6, as indicated by positions P3 to P5. The solid waveform in Figure 7 corresponds to the battery cooling device of embodiment 3 that is equipped with the short-circuit paths 58 and 62. On the other hand, the dashed waveform in the figure corresponds to the comparative example that is not equipped with the short-circuit paths 58 and 62.

As shown in FIG. 7, the cooling body 50 having the flow path configuration shown in FIG. 6 also provides the same effect as the cooling body 18 of embodiment 1. That is, the heat dissipation performance is locally reduced near the short-circuit passages 58 and 62 through which air passes, but when viewed as a whole tank section of the cooling body 50, the effect of suppressing the reduction in heat dissipation performance due to air mixing is obtained, and the suppression of air mixing suppresses the temperature rise of the refrigerant liquid. Furthermore, the difference (variation) in the battery temperature between the vicinity of the short-circuit passages 58 and 62 and the vicinity of the turn-back portion (near position P5) is successfully reduced compared to the comparative example.

The cooling body 50 of this embodiment has two U-shaped internal refrigerant passages 56 and 60 facing each other. With this configuration, the flow path length of the cooling body 50 in the horizontal direction (see FIG. 6) in each of the internal refrigerant passages 56 and 60 is shortened compared to an example having one U-shaped internal refrigerant passage. The shortening of the flow path length leads to a reduction in the contact area between the refrigerant liquid and the cooling body 50 (reduction in heat capacity). Therefore, the effect of reducing the battery temperature due to the difference in the position of the cooling body 50 in the horizontal direction (cooling body position on the horizontal axis in FIG. 7) is improved, making it possible to further improve heat dissipation performance.

In addition, the guide wall 44 shown in FIG. 5 may be similarly arranged on at least one of the outward paths 56a and 60a of the cooling body 50 shown in FIG. 6.

REFERENCE SIGNS LIST 1 Battery module 10 Battery cooling device 12, 64 Coolant circulation circuit 14 Gas-liquid separation tank 16 Pump 18, 40, 50 Cooling body 20 Cooling body tank portion 22 Cooling body supply port 24 Cooling body discharge port 26, 42, 56, 60 Internal cooling medium passage 26a, 56a, 60a Internal cooling medium passage outward passage 26b, 56b, 60b Internal cooling medium passage return passage 26c, 56c, 60c Partition wall (first partition wall)
26d Folded portion 26g End portion 28, 46, 58, 62 of first partition wall on the supply port side Short-circuit passage 30 Through hole 44 Guide wall 52 Internal space 52a of cooling body (tank portion) First internal space 52b Second internal space 54 Partition wall (second partition wall)

Claims (5)

a refrigerant circulation circuit in which a refrigerant liquid circulates;
a pump disposed on the refrigerant circulation circuit and configured to circulate the refrigerant liquid;
A cooling body disposed on the refrigerant circulation circuit and configured to cool the battery;
Equipped with
The cooling body is
a supply port into which the refrigerant liquid flows;
a discharge port that is disposed vertically above the supply port on the same plane as the supply port and that discharges the refrigerant liquid;
an internal refrigerant passage including an outward path through which the refrigerant liquid flowing in from the supply port flows, a return path through which the refrigerant liquid flows toward the discharge port after passing through the outward path and being reversed; and a first partition wall located between the supply port and the discharge port in the vertical direction and dividing an internal space of the cooling body into the outward path and the return path;
a short-circuit passage having one or a plurality of through holes penetrating the first partition wall and short-circuiting the supply port and the discharge port;
Including,
A battery cooling device characterized in that the one or more through holes are provided in the first partition at a position closer to the end on the supply port side than to the end on the folded portion side of the outward path and the return path, and have a cross-sectional area smaller than the cross-sectional area of the outward path. The battery cooling device according to claim 1 , wherein the one or more through holes are formed at an end of the first partition wall on a side of the supply port. The battery cooling device according to claim 1 or 2, characterized in that the internal refrigerant passage is arranged in the outward path so as to face the flow of the refrigerant liquid flowing in from the supply port, and includes a guide wall that guides the air that flows in from the supply port together with the refrigerant liquid to flow upward in the vertical direction. the supply port and the discharge port are arranged to overlap when viewed in the vertical direction,
The battery cooling device of any one of claims 1 to 3, characterized in that the one or more through holes include a through hole arranged so as to be aligned in the same straight line as the supply port and the exhaust port when viewed from the vertical direction. the cooling body includes first and second internal spaces obtained by dividing an internal space of the cooling body by a second partition wall, and a combination of the supply port, the discharge port, the internal refrigerant passage, and the short-circuit passage is provided for each of the first and second internal spaces;
The battery cooling device according to any one of claims 1 to 4, characterized in that the flow direction of the forward path of the internal refrigerant passage on the first internal space side is opposed to the flow direction of the forward path of the internal refrigerant passage on the second internal space side via the second partition.

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