JP2023017373A - battery cooling system - Google Patents

Abstract

To easily adjust temperatures of all batteries to a predetermined set temperature.SOLUTION: An inlet 30a of a bypass passage 30 is connected to an upper side in the vertical direction relative to mainstream piping 22. Drawing of a gas refrigerant toward the bypass passage 30 enables a liquid refrigerant flowing in the mainstream piping 22 to easily flow toward the downstream side in the refrigerant flowing direction in the mainstream piping 22. This can suppress reduction of a flow rate of the liquid refrigerant distributed to branch piping 23 connected to the downstream side in the refrigerant flowing direction relative to the mainstream piping 22. Since a bypass restrictor is provided in the bypass passage 30, this structure inhibits the liquid refrigerant flowing in the mainstream piping 22 from preferentially flowing into the bypass passage 30. Since the entire bypass passage 30 is located on the upper side in the vertical direction of the mainstream piping 22, this arrangement inhibits the liquid refrigerant flowing into the bypass passage 30 from being discharged to collective piping via the bypass passage 30.SELECTED DRAWING: Figure 3

Description

The present invention relates to a battery cooling system with a refrigeration cycle.

2. Description of the Related Art For example, Patent Document 1 is known as a battery cooling system that cools a battery using a refrigeration cycle and adjusts the temperature of the battery to a predetermined set temperature. A refrigeration cycle has a compressor, a condenser, a throttle, and a heat exchanger. The compressor compresses the refrigerant and discharges the refrigerant. The condenser condenses the refrigerant discharged from the compressor. The throttle reduces the pressure of the refrigerant condensed by the condenser. Refrigerant decompressed by the throttle flows through the heat exchanger. The heat exchanger exchanges heat between the refrigerant flowing inside and the battery.

Further, in the refrigeration cycle, when the temperatures of a plurality of batteries are adjusted, for example, a plurality of heat exchangers are arranged corresponding to each of the plurality of batteries. In this case, the refrigerating cycle has supply pipes for supplying the refrigerant condensed by the condenser to each of the plurality of heat exchangers. The supply pipe has a main pipe connected to the condenser and a plurality of branch pipes. Refrigerant condensed by the condenser flows through the main pipe. A plurality of branch pipes connect the main pipe and each heat exchanger, distribute the refrigerant from the main pipe and supply it to each heat exchanger. A plurality of branch pipes may be connected in parallel in the flow direction of the refrigerant with respect to the main pipe. Each branch pipe is provided with a throttle.

JP 2013-61099 A

By the way, for example, consider a case where all the refrigerant condensed by the condenser is liquid refrigerant. In this case, the inside of the mainstream pipe is filled with the liquid refrigerant. Then, even if a plurality of branch pipes are connected in parallel with the main pipe in the flow direction of the refrigerant, the liquid refrigerant is easily distributed to the branch pipes evenly. Therefore, in a plurality of heat exchangers, the flow rate of the liquid refrigerant supplied to each heat exchanger from each branch pipe is less likely to vary, and as a result, all batteries are easily adjusted to a predetermined set temperature. Become.

On the other hand, for example, it is conceivable that not all the refrigerant condensed by the condenser becomes liquid refrigerant, and the refrigerant condensed by the condenser is in a gas-liquid two-phase state in which liquid refrigerant and gas refrigerant are mixed. . At this time, if the inlet of each branch pipe is connected below the main pipe in the vertical direction, including the horizontal plane, the liquid refrigerant flowing through the main pipe will flow into the main pipe due to its own weight. It becomes easy to flow into the branch pipe connected to the upstream side in the flow direction. As a result, the flow rate of the liquid refrigerant distributed to the branch pipes connected downstream in the flow direction of the refrigerant with respect to the main pipe decreases. Therefore, in a plurality of heat exchangers, the flow rate of the liquid refrigerant supplied from each branch pipe to each heat exchanger varies, and as a result, it is difficult to adjust all the batteries to a predetermined set temperature. There is a risk of becoming.

A battery cooling system that solves the above problems includes a compressor that compresses a refrigerant and discharges the refrigerant, a condenser that condenses the refrigerant discharged from the compressor, and a throttle that decompresses the refrigerant condensed by the condenser. and a plurality of heat exchangers arranged corresponding to each of the plurality of batteries, in which the refrigerant decompressed by the throttle flows, and which exchange heat between the refrigerant and each of the batteries. wherein the refrigeration cycle has a supply pipe for supplying refrigerant condensed by the condenser to each of the plurality of heat exchangers, the supply pipe comprising a main pipe connected to the condenser; and a plurality of branch pipes that connect the pipes and the heat exchangers, distribute the refrigerant from the main pipe and supply the refrigerant to the heat exchangers, and the throttles are provided in the branch pipes. a battery cooling system in which the inlet of each of the branch pipes is connected below the main pipe in a vertical direction including a horizontal plane, and branched from the main pipe and from the heat exchanger to the A bypass passage connected to a passage leading to a compressor is provided, the bypass passage is provided with a bypass throttle, and an inlet of the bypass passage is connected vertically above the main pipe including the horizontal plane. At least a portion of the bypass passage is positioned vertically above the main pipe, and the bypass passage is a passage for the gas refrigerant in the main pipe from the heat exchanger to the compressor. to the

Here, for example, consider a case where not all the refrigerant condensed by the condenser becomes liquid refrigerant, but the refrigerant condensed by the condenser is in a gas-liquid two-phase state in which liquid refrigerant and gas refrigerant are mixed. In such a case, the liquid refrigerant tends to flow more vertically downward than the horizontal plane in the mainstream pipe due to its own weight, and the gas refrigerant tends to flow more vertically upward than the horizontal plane in the mainstream pipe. At this time, the inlet of the bypass passage is connected above the main pipe in the vertical direction including the horizontal plane. According to this, the gaseous refrigerant, which tends to flow upward in the vertical direction in the main pipe rather than in the horizontal plane, is more likely to be drawn toward the bypass passage. The bypass passage discharges the gas refrigerant in the main pipe to the passage from the heat exchanger to the compressor. The liquid refrigerant flowing inside the main pipe follows the drawing of the gas refrigerant toward the bypass passage, and easily flows toward the downstream side in the flow direction of the refrigerant inside the main pipe. As a result, a decrease in the flow rate of the liquid refrigerant distributed to the branch pipes connected downstream in the flow direction of the refrigerant with respect to the main pipe is suppressed.

Moreover, since the bypass throttle is provided in the bypass passage, the liquid refrigerant flowing in the main pipe is suppressed from preferentially flowing into the bypass passage. Therefore, the liquid refrigerant flowing in the main pipe is easily distributed evenly to each branch pipe. Furthermore, since at least a portion of the bypass passage is positioned vertically above the main pipe, even if the liquid refrigerant flows into the bypass passage, the liquid refrigerant flowing into the bypass passage exchanges heat through the bypass passage. It is suppressed from being discharged from the vessel to the passage leading to the compressor. Therefore, the liquid refrigerant flowing in the main pipe is easily distributed evenly to each branch pipe.

As described above, since the liquid refrigerant is easily distributed to the branch pipes evenly, the flow rate of the liquid refrigerant supplied from each branch pipe to each heat exchanger is less likely to vary in the plurality of heat exchangers. As a result, it is possible to easily adjust all the batteries to the preset set temperatures.

In the battery cooling system described above, the inlet of the bypass passage may be connected to a portion of the main pipe located downstream of a central portion in the flow direction of the coolant.
According to this, the liquid refrigerant flowing inside the main pipe follows the drawing of the gas refrigerant toward the bypass passage, and it becomes easier for the liquid refrigerant to flow further downstream in the flow direction of the refrigerant inside the main pipe. As a result, it is possible to more easily suppress a decrease in the flow rate of the liquid refrigerant distributed to the branch pipes connected downstream in the flow direction of the refrigerant with respect to the main pipe.

In the above battery cooling system, a branch pipe in which an inlet of the bypass passage is positioned furthest downstream of the plurality of branch pipes with respect to the main pipe in a flow direction of the refrigerant in the main pipe, and the branch pipe and adjacent branch pipes. Such a configuration is suitable for constructing a bypass passage branched from the main pipe and connected to a passage extending from the heat exchanger to the compressor.

In the battery cooling system described above, an inlet of the bypass passage may be connected to a portion of the main pipe located most downstream in a flow direction of the coolant.
According to this, the liquid refrigerant flowing inside the main pipe follows the drawing of the gas refrigerant toward the bypass passage, and it becomes easier for the liquid refrigerant to flow further downstream in the flow direction of the refrigerant inside the main pipe. As a result, it is possible to more easily suppress a decrease in the flow rate of the liquid refrigerant distributed to the branch pipes connected downstream in the flow direction of the refrigerant with respect to the main pipe.

The battery cooling system described above includes an on-off valve provided in the bypass passage, and an on-off valve control unit that controls driving of the on-off valve. It is preferable to control the driving of the on-off valve so that the on-off valve is closed when the temperature is lower than the saturation temperature of the refrigerant determined based on the pressure in the main pipe.

When the temperature of the refrigerant flowing through the main pipe is lower than the saturation temperature, all the refrigerant flowing through the main pipe is liquid refrigerant. Therefore, the on-off valve control unit controls driving of the on-off valve so that the on-off valve is closed when the temperature of the refrigerant flowing through the main pipe is lower than the saturation temperature. According to this, even if the liquid refrigerant flows into the bypass passage, the liquid refrigerant that has flowed into the bypass passage is not discharged to the passage from the heat exchanger to the compressor via the bypass passage. Therefore, since the liquid refrigerant flowing in the main pipe is efficiently distributed to the respective branch pipes, it is possible to easily adjust all the batteries to the predetermined set temperatures.

In the above battery cooling system, the bypass throttle is a variable throttle, and includes a variable throttle control unit that controls driving of the bypass throttle to control the opening degree of the bypass throttle, and the variable throttle control unit the bypass throttle so that the opening degree of the bypass throttle becomes small when the temperature of the refrigerant flowing through the mainstream pipe is lower than the saturation temperature of the refrigerant determined based on the pressure in the mainstream pipe; should be controlled.

When the temperature of the refrigerant flowing through the main pipe is lower than the saturation temperature, all the refrigerant flowing through the main pipe is liquid refrigerant. Therefore, when the temperature of the refrigerant flowing through the main pipe is lower than the saturation temperature, the variable throttle control unit controls the driving of the bypass throttle so that the opening degree of the bypass throttle becomes small. According to this, even if the liquid refrigerant flows into the bypass passage, the liquid refrigerant that has flowed into the bypass passage is less likely to be discharged to the passage from the heat exchanger to the compressor via the bypass passage. Therefore, since the liquid refrigerant flowing in the main pipe is efficiently distributed to the respective branch pipes, it is possible to easily adjust all the batteries to the predetermined set temperatures.

In the battery cooling system described above, a float valve may be provided at an inlet of the bypass passage.
For example, when all the refrigerant condensed by the condenser is liquid refrigerant, the inside of the main pipe is filled with liquid refrigerant, and part of the liquid refrigerant in the main pipe may flow into the bypass passage. At this time, the liquid refrigerant flowing into the bypass passage causes the float valve to float, causing the float valve to block the bypass passage. According to this, even if the liquid refrigerant flows into the bypass passage, the liquid refrigerant that has flowed into the bypass passage is less likely to be discharged to the passage from the heat exchanger to the compressor via the bypass passage. Therefore, since the liquid refrigerant flowing in the main pipe is efficiently distributed to the respective branch pipes, it is possible to easily adjust all the batteries to the predetermined set temperatures.

In the above battery cooling system, the refrigerating cycle has an accumulator disposed in the middle of a passage from the heat exchanger to the compressor and allowing gas refrigerant to flow out to the compressor, and the bypass passage may be connected to a passage leading from the heat exchanger to the accumulator.

In the refrigeration cycle, the gas refrigerant in the accumulator becomes saturated vapor. Here, by discharging the gas refrigerant in the mainstream pipe to the passage from the heat exchanger to the accumulator via the bypass passage, the refrigerant state at the outlet of each heat exchanger can be easily turned into wet vapor. Therefore, the state of the refrigerant passing through each heat exchanger can be maintained as wet steam up to the outlet of each heat exchanger, thereby facilitating uniform adjustment of the temperature of the entire battery to a predetermined set temperature. be able to.

In the above battery cooling system, the refrigerating cycle has an accumulator disposed in the middle of a passage from the heat exchanger to the compressor and allowing gas refrigerant to flow out to the compressor, and the bypass passage may be connected to a passage leading from the accumulator to the compressor.

In the refrigeration cycle, the gas refrigerant in the accumulator becomes saturated vapor. Here, by discharging the gas refrigerant in the main pipe through the bypass passage to the passage from the accumulator to the compressor, the state of the refrigerant at the inlet of the compressor can be easily changed to dry vapor. As a result, it is possible to improve the compression efficiency of the refrigerant in the compressor.

According to the present invention, it is possible to easily adjust all the batteries to a predetermined set temperature.

1 is a schematic configuration diagram showing a battery cooling system according to an embodiment; FIG. Schematic diagram showing a battery cooling system. Sectional drawing which shows a part of supply piping and a bypass channel. Sectional drawing which shows a part of supply piping and bypass passage in another embodiment. Sectional drawing for demonstrating the float valve in another embodiment. Sectional drawing for demonstrating a float valve. Sectional drawing for demonstrating a float valve. The schematic block diagram which shows the battery cooling system in another embodiment. The schematic block diagram which shows the battery cooling system in another embodiment.

An embodiment embodying a battery cooling system will be described below with reference to FIGS. 1 to 3. FIG. The battery cooling system of this embodiment is mounted on a vehicle, for example.
(Overall Configuration of Battery Cooling System 10)
As shown in FIGS. 1 and 2 , the battery cooling system 10 has a refrigeration cycle 11 . The battery cooling system 10 cools the plurality of batteries 12 using the refrigeration cycle 11 and adjusts the temperature of the plurality of batteries 12 to a predetermined set temperature. In addition, in FIG. 2, each battery 12 is indicated by a two-dot chain line. The battery 12 is in the shape of a rectangular block. The battery 12 is configured by arranging a plurality of battery cells (not shown) in parallel. The direction in which the battery cells are arranged is the long side direction of the battery 12 . Battery cells are, for example, lithium-ion batteries and nickel-metal hydride batteries. The plurality of batteries 12 are arranged side by side in a direction orthogonal to the direction in which the battery cells are arranged side by side. Therefore, the plurality of batteries 12 are arranged side by side with the short sides of the batteries 12 aligned. The plurality of batteries 12 are packaged as one battery pack, for example, by being accommodated in a housing (not shown).

(Configuration of refrigeration cycle 11)
The refrigeration cycle 11 has a compressor 13 , a condenser 14 , a throttle 15 , a plurality of heat exchangers 16 and an accumulator 17 . The compressor 13 compresses a low-temperature, low-pressure gas refrigerant and discharges a high-temperature, high-pressure gas refrigerant. The condenser 14 condenses the gas refrigerant discharged from the compressor 13 . The throttle 15 reduces the pressure of the high-temperature, high-pressure refrigerant condensed by the condenser 14 . The refrigerant is depressurized by the throttle 15 and becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant. Gas-liquid two-phase refrigerant decompressed by the throttle 15 flows through each heat exchanger 16 . The accumulator 17 allows gas refrigerant to flow out to the compressor 13 and prevents liquid refrigerant to flow out to the compressor 13 . The accumulator 17 and the compressor 13 are connected by a pipe 18 . A pipe 18 constitutes a passage from the accumulator 17 to the compressor 13 . Compressor 13 and condenser 14 are connected by pipe 19 .

As shown in FIG. 2, the plurality of heat exchangers 16 are arranged corresponding to each of the plurality of batteries 12 . Each heat exchanger 16 is thermally coupled with each battery 12 . The plurality of heat exchangers 16 exchange heat between the refrigerant flowing inside and each battery 12 . The plurality of heat exchangers 16 are arranged side by side in the direction in which the plurality of batteries 12 are arranged. Each heat exchanger 16 has, for example, a flat rectangular tube shape. All heat exchangers 16 have the same shape. Therefore, each heat exchanger 16 has the same flow passage cross-sectional area.

Each heat exchanger 16 is connected to an accumulator 17 via a collective pipe 20 . Refrigerant discharged from each heat exchanger 16 flows into the accumulator 17 via the collecting pipe 20 . The collecting pipe 20 constitutes a passage from each heat exchanger 16 to the accumulator 17 . Collective pipe 20 , accumulator 17 , and pipe 18 form a passage from heat exchanger 16 to compressor 13 . Therefore, the accumulator 17 is arranged in the middle of the passage from the heat exchanger 16 to the compressor 13 .

(Configuration of supply pipe 21)
The refrigeration cycle 11 has a supply pipe 21 . The supply pipe 21 supplies the refrigerant condensed by the condenser 14 to each of the plurality of heat exchangers 16 . The supply pipe 21 has a main pipe 22 and a plurality of branch pipes 23 . The mainstream pipe 22 has a circular tubular shape. Main stream pipe 22 is connected to condenser 14 . The refrigerant condensed by the condenser 14 flows through the main pipe 22 . Each branch pipe 23 has a circular tubular shape. A plurality of branch pipes 23 connect the main pipe 22 and each heat exchanger 16 , distribute the refrigerant from the main pipe 22 , and supply it to each heat exchanger 16 .

A throttle 15 is provided in each branch pipe 23 . Each throttle 15 is an orifice formed by reducing the passage cross-sectional area of a part of each branch pipe 23 . Each diaphragm 15 is a fixed diaphragm. Each aperture 15 has the same passage cross-sectional area.

As shown in FIG. 3, the mainstream pipe 22 extends horizontally from the condenser 14 . The flow direction of the refrigerant flowing from the condenser 14 inside the main pipe 22 is horizontal. In FIG. 3, the arrow X1 indicates the flow direction of the coolant. The end of the mainstream pipe 22 opposite to the condenser 14 is closed. Therefore, the most downstream portion of the main pipe 22 in the flow direction of the refrigerant is closed.

A plurality of branch pipes 23 are connected in parallel to the main pipe 22 in the refrigerant flow direction. Each branch pipe 23 extends vertically downward from the bottom of the main pipe 22 . Therefore, the plurality of branch pipes 23 are connected to the main pipe 22 with the inlets 23 a of the respective branch pipes 23 connected vertically downward to the main pipe 22 . In FIG. 3, the vertical direction is indicated by an arrow Z1.

(Configuration of Bypass Passage 30)
As shown in FIGS. 1 and 2 , the battery cooling system 10 has a bypass passage 30 . The bypass passage 30 branches off from the main pipe 22 . The bypass passage 30 is connected to the collective pipe 20 . Therefore, the bypass passage 30 is branched from the main pipe 22 and connected to a passage extending from the heat exchanger 16 to the accumulator 17 . Therefore, the bypass passage 30 is branched from the main pipe 22 and connected to a passage extending from the heat exchanger 16 to the compressor 13 . The bypass passage 30 discharges the gas refrigerant in the main pipe 22 to the collective pipe 20 . Therefore, the bypass passage 30 discharges the gas refrigerant in the main pipe 22 to the passage from the heat exchanger 16 to the compressor 13 .

A bypass throttle 31 is provided in the bypass passage 30 . The bypass throttle 31 is an orifice in which the passage cross-sectional area of a part of the bypass passage 30 is reduced. The bypass throttle 31 is a variable throttle. Therefore, the bypass throttle 31 can adjust the passage cross-sectional area of the bypass passage 30 by adjusting its own passage cross-sectional area. The bypass throttle 31 is a flow control valve whose opening is electrically controlled. The gas refrigerant flowing through the bypass passage 30 is decompressed by the bypass throttle 31 . Therefore, the bypass passage 30 discharges the decompressed gas refrigerant to the collection pipe 20 .

As shown in FIG. 3, the bypass passage 30 is, for example, piping. The bypass passage 30 has a circular tubular shape. The bypass passage 30 extends vertically upward from the top of the main pipe 22 and then extends toward the collective pipe 20 . Therefore, the inlet 30 a of the bypass passage 30 is connected vertically above the main pipe 22 , and the entire bypass passage 30 is positioned above the main pipe 22 in the vertical direction.

In the main pipe 22, the inlet 30a of the bypass passage 30 is the branch pipe 23 located most downstream in the flow direction of the refrigerant with respect to the main pipe 22 among the plurality of branch pipes 23, and the branch pipe 23 adjacent to the branch pipe 23. It is connected to a portion corresponding to the position between the pipe 23 . Therefore, the inlet 30a of the bypass passage 30 is connected to a portion of the main pipe 22 located downstream of the central portion in the refrigerant flow direction.

(Regarding the electrical configuration of the battery cooling system 10)
As shown in FIGS. 1 and 2 , the battery cooling system 10 includes a pressure sensor 41 that detects the pressure inside the main pipe 22 . The battery cooling system 10 also includes a temperature sensor 42 that detects the temperature of the coolant flowing through the main pipe 22 .

The battery cooling system 10 has a controller 40 . The control unit 40 has a central processing control unit (CPU). The control unit 40 also includes a memory including a read-only memory (ROM) in which various programs, maps, and the like are stored in advance, and a random access memory (RAM) in which CPU calculation results and the like are temporarily stored. Furthermore, the control unit 40 has a timer counter, an input interface, an output interface, and the like.

The controller 40 is electrically connected to the pressure sensor 41 . From the pressure sensor 41 , the control unit 40 receives information about the pressure in the main pipe 22 detected by the pressure sensor 41 . Also, the controller 40 is electrically connected to the temperature sensor 42 . From the temperature sensor 42 , the control unit 40 receives information about the temperature of the refrigerant detected by the temperature sensor 42 .

The controller 40 is electrically connected to the bypass throttle 31 . The control unit 40 stores in advance a program for controlling driving of the bypass diaphragm 31 in order to control the opening degree of the bypass diaphragm 31 . Therefore, the control unit 40 functions as a variable aperture control unit that controls driving of the bypass aperture 31 in order to control the opening degree of the bypass aperture 31 .

The controller 40 stores in advance a map that associates the pressure in the main pipe 22 with the saturation temperature of the refrigerant. The control unit 40 obtains in advance the saturation temperature of the refrigerant based on the pressure in the main pipe 22 detected by the pressure sensor 41 using a map.

When the temperature of the refrigerant flowing through the main pipe 22 is the same as the saturation temperature of the refrigerant which is determined based on the pressure inside the main pipe 22, the control unit 40 sets the opening degree of the bypass throttle 31 to a predetermined opening degree. A program for controlling the driving of the bypass diaphragm 31 is stored in advance. On the other hand, when the temperature of the refrigerant flowing through the main pipe 22 is lower than the saturation temperature of the refrigerant that is determined based on the pressure inside the main pipe 22, the control unit 40 reduces the degree of opening of the bypass throttle 31. A program for controlling the driving of the bypass diaphragm 31 is stored in advance. Therefore, when the temperature of the refrigerant flowing through the main pipe 22 is lower than the saturation temperature of the refrigerant which is determined based on the pressure inside the main pipe 22, the controller 40 controls the opening degree of the bypass throttle 31 to be small. , the drive of the bypass diaphragm 31 is controlled. Specifically, when the temperature of the refrigerant flowing through the main pipe 22 is lower than the saturation temperature, the control unit 40 makes the degree of opening of the bypass throttle 31 smaller than a predetermined degree of opening. The predetermined opening degree of the bypass throttle 31 is an opening degree at which the passage cross-sectional area of the bypass throttle 31 is smaller than the sum of the passage cross-sectional areas of the respective throttles 15 .

(action)
Next, the operation of this embodiment will be described.
By the way, when the temperature of the refrigerant flowing through the main pipe 22 is lower than the saturation temperature, it is presumed that all the refrigerant condensed by the condenser 14 flows through the main pipe 22 in a liquid state. In this case, the inside of the main pipe 22 is filled with the liquid refrigerant. Therefore, when the temperature of the refrigerant flowing through the main pipe 22 is lower than the saturation temperature, the control unit 40 controls the driving of the bypass throttle 31 so that the opening degree of the bypass throttle 31 is smaller than a predetermined opening degree. do. Therefore, even if liquid refrigerant flows into the bypass passage 30 , the liquid refrigerant that has flowed into the bypass passage 30 is less likely to be discharged to the collecting pipe 20 via the bypass passage 30 . As a result, even if a plurality of branch pipes 23 are connected in parallel with the main pipe 22 in the flow direction of the refrigerant, the liquid refrigerant is easily distributed equally to each branch pipe 23 . Therefore, in the plurality of heat exchangers 16, variation in the flow rate of the liquid refrigerant supplied from each branch pipe 23 to each heat exchanger 16 is less likely to occur. Then, heat is exchanged between the liquid refrigerant and each battery 12 via each heat exchanger 16, and each battery 12 is cooled by the latent heat required when the liquid refrigerant changes to gas refrigerant, and all Battery 12 is adjusted to a predetermined set temperature.

On the other hand, when the temperature of the refrigerant flowing through the main pipe 22 is the same as the saturation temperature, all the refrigerant condensed by the condenser 14 does not become liquid refrigerant, and the refrigerant condensed by the condenser 14 becomes liquid refrigerant and gas refrigerant. It is presumed to be a gas-liquid two-phase state in which In such a case, the liquid refrigerant tends to flow vertically below the horizontal plane in the main pipe 22 due to its own weight, and the gas refrigerant tends to flow vertically above the horizontal plane within the main pipe 22 .

Therefore, when the temperature of the refrigerant flowing through the main pipe 22 is the same as the saturation temperature, the control unit 40 controls the driving of the bypass throttle 31 so that the opening degree of the bypass throttle 31 becomes a predetermined opening degree. Here, the inlet 30a of the bypass passage 30 is connected to the upper part of the main pipe 22 in the vertical direction. Therefore, the gaseous refrigerant, which tends to flow upward in the vertical direction in the mainstream pipe 22 rather than in the horizontal plane, is more likely to be drawn toward the bypass passage 30 as indicated by arrow R1 in FIG. The bypass passage 30 discharges the gas refrigerant in the main pipe 22 to the collective pipe 20 . The liquid refrigerant flowing inside the main pipe 22 follows the drawing of the gas refrigerant toward the bypass passage 30 and easily flows downstream in the flow direction of the refrigerant inside the main pipe 22 . As a result, the flow rate of the liquid refrigerant distributed to the branch pipe 23 connected to the downstream side of the main pipe 22 in the flow direction of the refrigerant is suppressed from decreasing.

Moreover, since the bypass throttle 31 is provided in the bypass passage 30 , preferential flow of the liquid refrigerant flowing through the main pipe 22 into the bypass passage 30 is suppressed. Therefore, the liquid refrigerant flowing through the main pipe 22 is easily distributed equally to the branch pipes 23 . Furthermore, since the entire bypass passage 30 is located above the main pipe 22 in the vertical direction, even if the liquid refrigerant flows into the bypass passage 30, the liquid refrigerant that has flowed into the bypass passage 30 does not pass through the bypass passage 30. It is suppressed to be discharged to the collecting pipe 20 through. Therefore, the liquid refrigerant flowing through the main pipe 22 is easily distributed equally to the branch pipes 23 . Therefore, in the plurality of heat exchangers 16, the flow rate of the liquid refrigerant supplied from each branch pipe 23 to each heat exchanger 16 is less likely to vary. is easily adjusted to

In the refrigeration cycle 11, the gas refrigerant in the accumulator 17 becomes saturated steam. Here, the gas refrigerant in the main pipe 22 is discharged through the bypass passage 30 to the collection pipe 20 which is a passage from each heat exchanger 16 to the accumulator 17, thereby reducing the refrigerant at the outlet of each heat exchanger 16. The state tends to become wet steam. Therefore, since the state of the refrigerant passing through each heat exchanger 16 is easily maintained as wet steam until the outlet of each heat exchanger 16, the temperature of the entire battery 12 is uniformly adjusted to a predetermined set temperature. becomes easier.

(effect)
The following effects can be obtained in the above embodiment.
(1) The inlet 30a of the bypass passage 30 is connected vertically above the main pipe 22 . This makes it easier for the gas refrigerant, which tends to flow upward in the vertical direction in the mainstream pipe 22 than in the horizontal plane, to be drawn toward the bypass passage 30 . The bypass passage 30 discharges the gas refrigerant in the main pipe 22 to the collective pipe 20 . The liquid refrigerant flowing inside the main pipe 22 follows the drawing of the gas refrigerant toward the bypass passage 30 and easily flows downstream in the flow direction of the refrigerant inside the main pipe 22 . As a result, the flow rate of the liquid refrigerant distributed to the branch pipe 23 connected to the downstream side of the main pipe 22 in the flow direction of the refrigerant is suppressed from decreasing.

Moreover, since the bypass throttle 31 is provided in the bypass passage 30 , preferential flow of the liquid refrigerant flowing through the main pipe 22 into the bypass passage 30 is suppressed. Therefore, the liquid refrigerant flowing through the main pipe 22 is easily distributed equally to the branch pipes 23 . Furthermore, the entire bypass passage 30 is located above the main pipe 22 in the vertical direction. Therefore, even if the liquid refrigerant flows into the bypass passage 30 , the liquid refrigerant that has flowed into the bypass passage 30 is suppressed from being discharged to the collecting pipe 20 via the bypass passage 30 . Therefore, the liquid refrigerant flowing through the main pipe 22 is easily distributed equally to the branch pipes 23 .

As described above, since the liquid refrigerant is easily distributed to each branch pipe 23 evenly, in the plurality of heat exchangers 16, the flow rate of the liquid refrigerant supplied from each branch pipe 23 to each heat exchanger 16 varies. it gets harder. As a result, it is possible to easily adjust all the batteries 12 to a predetermined set temperature.

(2) The inlet 30a of the bypass passage 30 is connected to a portion of the main pipe 22 located downstream of the central portion in the refrigerant flow direction. According to this, the liquid refrigerant flowing in the main pipe 22 follows the drawing of the gas refrigerant toward the bypass passage 30, and more easily flows downstream in the flow direction of the refrigerant in the main pipe 22. Become. As a result, it is possible to more easily suppress a decrease in the flow rate of the liquid refrigerant distributed to the branch pipe 23 connected downstream of the main pipe 22 in the flow direction of the refrigerant.

(3) the branch pipe 23 in which the inlet 30a of the bypass passage 30 is located most downstream in the flow direction of the refrigerant with respect to the main pipe 22 among the plurality of branch pipes 23 in the main pipe 22; It is connected to a portion corresponding to a position between adjacent branch pipes 23 . Such a configuration is suitable for constructing the bypass passage 30 branched from the main pipe 22 and connected to the collective pipe 20 .

(4) When the temperature of the refrigerant flowing through the main pipe 22 is lower than the saturation temperature, the control unit 40 controls driving of the bypass throttle 31 so that the opening degree of the bypass throttle 31 is reduced. Accordingly, even if the liquid refrigerant flows into the bypass passage 30 , the liquid refrigerant that has flowed into the bypass passage 30 is less likely to be discharged to the collecting pipe 20 via the bypass passage 30 . Therefore, since the liquid refrigerant flowing in the main pipe 22 is efficiently distributed to the respective branch pipes 23, it is possible to easily adjust all the batteries 12 to a predetermined set temperature.

(5) The bypass passage 30 is connected to the collective pipe 20 which is a passage from each heat exchanger 16 to the accumulator 17 . In the refrigeration cycle 11, the gas refrigerant in the accumulator 17 becomes saturated steam. Here, the gas refrigerant in the main pipe 22 is discharged through the bypass passage 30 to the collection pipe 20 which is a passage from each heat exchanger 16 to the accumulator 17, thereby reducing the refrigerant at the outlet of each heat exchanger 16. Conditions can be facilitated to wet steam. Therefore, since the state of the refrigerant passing through each heat exchanger 16 can be maintained as wet steam up to the outlet of each heat exchanger 16, the temperature of the entire battery 12 can be uniformly adjusted to a predetermined set temperature. can be made easier.

(Change example)
It should be noted that the above embodiment can be implemented with the following modifications. The above embodiments and the following modifications can be combined with each other within a technically consistent range.

O As shown in FIG. 4, the inlet 30a of the bypass passage 30 may be connected to the most downstream portion of the main pipe 22 in the refrigerant flow direction. According to this, the liquid refrigerant flowing in the main pipe 22 follows the drawing of the gas refrigerant toward the bypass passage 30, and more easily flows downstream in the flow direction of the refrigerant in the main pipe 22. Become. As a result, it is possible to more easily suppress a decrease in the flow rate of the liquid refrigerant distributed to the branch pipe 23 connected downstream of the main pipe 22 in the flow direction of the refrigerant.

A float valve 50 may be provided at the inlet 30a of the bypass passage 30, as shown in FIGS. In this case, the bypass passage 30 is formed with a valve seat 51 on which the float valve 50 is seated. The float valve 50 can be moved toward and away from the valve seat 51 . As shown in FIGS. 5 and 6 , the float valve 50 opens the bypass passage 30 by separating from the valve seat 51 . Further, as shown in FIG. 7 , the float valve 50 closes the bypass passage 30 by being seated on the valve seat 51 .

For example, when all the refrigerant condensed by the condenser 14 is liquid refrigerant, the inside of the main pipe 22 is filled with liquid refrigerant, and part of the liquid refrigerant in the main pipe 22 may flow into the bypass passage 30. be. At this time, the liquid refrigerant flowing into the bypass passage 30 floats the float valve 50 so that the float valve 50 closes the bypass passage 30 . Accordingly, even if the liquid refrigerant flows into the bypass passage 30 , the liquid refrigerant that has flowed into the bypass passage 30 is less likely to be discharged to the collecting pipe 20 via the bypass passage 30 . Therefore, since the liquid refrigerant flowing in the main pipe 22 is efficiently distributed to the respective branch pipes 23, it is possible to easily adjust all the batteries 12 to a predetermined set temperature.

In addition, in the case of the embodiments shown in FIGS. 5, 6 and 7, the bypass throttle 31 may be a fixed throttle. In this case, the passage cross-sectional area of the bypass throttle 31 is preferably smaller than the sum of the passage cross-sectional areas of the respective throttles 15 .

O As shown in FIG. 8 , the battery cooling system 10 may include an on-off valve 60 provided in the bypass passage 30 . The on-off valve 60 is arranged at a portion closer to the mainstream pipe 22 than the bypass throttle 31 in the bypass passage 30 . The on-off valve 60 is an electromagnetic valve whose open state and closed state are electrically controlled. The controller 40 is electrically connected to the on-off valve 60 . The control unit 40 controls driving of the on-off valve 60 so that the on-off valve 60 opens when the temperature of the refrigerant flowing through the main pipe 22 is the same as the saturation temperature. Further, the control unit 40 controls driving of the on-off valve 60 so that the on-off valve 60 is closed when the temperature of the refrigerant flowing through the main pipe 22 is lower than the saturation temperature. Therefore, the control unit 40 functions as an on-off valve control unit that controls driving of the on-off valve 60 .

When the temperature of the refrigerant flowing through the main pipe 22 is lower than the saturation temperature, all the refrigerant flowing through the main pipe 22 is liquid refrigerant. Therefore, the control unit 40 controls driving of the on-off valve 60 so that the on-off valve 60 is closed when the temperature of the refrigerant flowing through the main pipe 22 is lower than the saturation temperature. According to this, even if the liquid refrigerant flows into the bypass passage 30 , the liquid refrigerant that has flowed into the bypass passage 30 will not be discharged to the collecting pipe 20 via the bypass passage 30 . Therefore, since the liquid refrigerant flowing in the main pipe 22 is efficiently distributed to the respective branch pipes 23, it is possible to easily adjust all the batteries 12 to a predetermined set temperature.

In addition, in the case of the embodiment shown in FIG. 8, the bypass throttle 31 may be a fixed throttle. In this case, the passage cross-sectional area of the bypass throttle 31 is preferably smaller than the sum of the passage cross-sectional areas of the respective throttles 15 .

O As shown in FIG. 9 , the bypass passage 30 may be connected to the pipe 18 that is a passage from the accumulator 17 to the compressor 13 . In the refrigeration cycle 11, the gas refrigerant in the accumulator 17 becomes saturated steam. Here, by discharging the gas refrigerant in the main pipe 22 through the bypass passage 30 to the pipe 18 which is a passage from the accumulator 17 to the compressor 13, the state of the refrigerant at the inlet of the compressor 13 is changed to dry vapor. can be made easier. As a result, the refrigerant compression efficiency in the compressor 13 can be improved.

O In the embodiment, each branch pipe 23 does not have to extend vertically downward from the bottom of the main pipe 22 . For example, the inlet 23a of each branch pipe 23 may be connected to a portion of the main pipe 22 positioned in the horizontal direction. The point is that the inlet 23a of each branch pipe 23 should be connected to the main pipe 22 vertically downward including the horizontal plane.

O In the embodiment, the bypass passage 30 does not have to extend vertically upward from the top of the mainstream pipe 22 . For example, the inlet 30a of the bypass passage 30 may be connected to a horizontally positioned portion of the main pipe 22 . After the bypass passage 30 extends horizontally from the main pipe 22 , the bypass passage 30 may extend vertically above the main pipe 22 and then extend toward the collective pipe 20 . In short, the inlet 30a of the bypass passage 30 is connected above the main pipe 22 in the vertical direction including the horizontal plane, and at least a part of the bypass passage 30 is positioned above the main pipe 22 in the vertical direction. All you have to do is

O In the embodiment, the inlet 30a of the bypass passage 30 may be connected to a portion of the main pipe 22 located upstream of the central portion in the flow direction of the refrigerant.
In the embodiment, the predetermined degree of opening of the bypass throttle 31 may be such that the passage cross-sectional area of the bypass throttle 31 is the same as the sum of the passage cross-sectional areas of the respective throttles 15 .

In the embodiment, the predetermined degree of opening of the bypass throttle 31 may be such that the passage cross-sectional area of the bypass throttle 31 is larger than the sum of the passage cross-sectional areas of the respective throttles 15 .
O In the embodiment, the bypass throttle 31 may be a fixed throttle. In this case, the passage cross-sectional area of the bypass throttle 31 is preferably smaller than the sum of the passage cross-sectional areas of the respective throttles 15 .

(circle) in embodiment, the shape of the heat exchanger 16 is not specifically limited.
(circle) in embodiment, the number of the heat exchangers 16 is not specifically limited. The number of heat exchangers 16 is appropriately changed according to the number of batteries 12 . The number of branch pipes 23 is appropriately changed according to the number of heat exchangers 16 .

DESCRIPTION OF SYMBOLS 10... Battery cooling system, 11... Refrigeration cycle, 12... Battery, 13... Compressor, 14... Condenser, 15... Condenser, 16... Heat exchanger, 17... Accumulator, 21... Supply pipe, 22... Main stream pipe, 23 Branch pipe 23a Inlet 30 Bypass passage 30a Inlet 31 Bypass throttle 40 Control section functioning as variable throttle control section and on-off valve control section 50 Float valve 60 On-off valve.

Claims (9)

a compressor that compresses a refrigerant and discharges the refrigerant;
a condenser for condensing the refrigerant discharged from the compressor;
a throttle for decompressing the refrigerant condensed by the condenser;
A refrigeration cycle having a plurality of heat exchangers arranged corresponding to each of the plurality of batteries and having a refrigerant decompressed by the throttle flow therein to exchange heat between the refrigerant and the batteries,
The refrigeration cycle has a supply pipe that supplies the refrigerant condensed by the condenser to each of the plurality of heat exchangers,
The supply pipe is
a mainstream pipe connected to the condenser;
a plurality of branch pipes connecting the main pipe and each heat exchanger, distributing the refrigerant from the main pipe and supplying it to each heat exchanger;
Each of the branch pipes is provided with the throttle,
A battery cooling system in which the inlet of each branch pipe is connected vertically below the main pipe, including a horizontal plane,
A bypass passage branched from the main pipe and connected to a passage from the heat exchanger to the compressor,
A bypass throttle is provided in the bypass passage,
an inlet of the bypass passage is connected vertically above the main pipe including the horizontal plane, and at least a portion of the bypass passage is positioned above the main pipe in the vertical direction;
The battery cooling system, wherein the bypass passage discharges gas refrigerant in the main pipe to a passage extending from the heat exchanger to the compressor. 2. The battery cooling system according to claim 1, wherein the inlet of the bypass passage is connected to a portion of the main pipe located downstream of a central portion in the flow direction of the coolant. A branch pipe in which the entrance of the bypass passage is located most downstream in the flow direction of the refrigerant with respect to the main pipe among the plurality of branch pipes in the main pipe, and a branch pipe adjacent to the branch pipe. 3. The battery cooling system according to claim 2, wherein the battery cooling system is connected to a portion corresponding to a position between . 3. The battery cooling system according to claim 2, wherein the inlet of the bypass passage is connected to a most downstream portion of the main pipe in the flow direction of the coolant. an on-off valve provided in the bypass passage;
an on-off valve control unit that controls driving of the on-off valve,
The on-off valve controller controls the on-off valve so that the on-off valve closes when the temperature of the refrigerant flowing through the main pipe is lower than the saturation temperature of the refrigerant determined based on the pressure in the main pipe. 5. The battery cooling system according to any one of claims 1 to 4, wherein the drive of the valve is controlled. The bypass throttle is a variable throttle,
a variable aperture control unit for controlling driving of the bypass aperture in order to control the opening degree of the bypass aperture;
The variable throttle control unit reduces the opening degree of the bypass throttle when the temperature of the refrigerant flowing through the main pipe is lower than the saturation temperature of the refrigerant determined based on the pressure in the main pipe. 6. The battery cooling system according to any one of claims 1 to 5, wherein the driving of the bypass throttle is controlled at the same time. The battery cooling system according to any one of claims 1 to 6, wherein a float valve is provided at an inlet of the bypass passage. The refrigeration cycle has an accumulator disposed in the middle of a passage from the heat exchanger to the compressor and allowing gas refrigerant to flow out to the compressor,
The battery cooling system according to any one of claims 1 to 7, wherein the bypass passage is connected to a passage extending from the heat exchanger to the accumulator. The refrigeration cycle has an accumulator disposed in the middle of a passage from the heat exchanger to the compressor and allowing gas refrigerant to flow out to the compressor,
The battery cooling system according to any one of claims 1 to 7, wherein the bypass passage is connected to a passage extending from the accumulator to the compressor.

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