JP2021120598A - Cooling device - Google Patents

Abstract

To provide a cooling device capable of restraining the backflow of a liquid-phase cooling refrigerant from liquid-phase piping to gas-phase piping through connection piping, and capable of discharging the liquid-phase refrigerant in the gas-phase piping into the liquid-phase piping through the connection piping.SOLUTION: A cooling device includes an evaporating part for evaporating a liquid-phase refrigerant, a condensing part disposed above the evaporating part and condensing a gas-phase refrigerant, gas-phase piping for guiding the gas-phase refrigerant from the evaporating part to the condensing part, liquid-phase piping for guiding the liquid-phase refrigerant from the condensing part to the evaporating part, and connection piping for connecting the gas-phase piping and the liquid-phase piping. The cooling device further includes a control valve provided in the connection piping and controlling the flow of the refrigerant between the gas-phase piping and the liquid-phase piping by changing an opening and closing degree of a flow passage in the connection piping, and a control device for controlling the control valve so that the opening and closing degree is reduced when pressure in the liquid-phase piping side is higher than pressure in the gas-phase piping side and the opening and closing degree is increased when the pressure in the liquid-phase piping side is lower than the pressure in the gas-phase piping side.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cooling device.

Conventionally, in a vehicle, a connection for connecting a liquid phase pipe through which a liquid phase refrigerant flows and a gas phase pipe through which a gas phase refrigerant flows to a cooling device that cools a battery, which is a cooling object, by boiling and condensing the refrigerant. It is known to provide piping (Patent Document 1 and the like).

Japanese Unexamined Patent Publication No. 2019-035572

In the cooling device, the liquid phase refrigerant enters the gas phase pipe by inclining when the vehicle descends, or the gas phase refrigerant in the gas phase pipe is cooled by the outside air and condensed into the liquid phase refrigerant. Therefore, it is conceivable that the liquid phase refrigerant in the gas phase pipe is discharged to the liquid phase pipe via the connection pipe. However, if the pressure on the liquid phase pipe side is higher than the pressure on the gas phase pipe side depending on the operating conditions of the vehicle, the liquid phase refrigerant in the liquid phase pipe flows back into the gas phase pipe via the connection pipe due to the pressure difference. There is a risk.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent backflow of the liquid phase cooling refrigerant from the liquid phase pipe to the gas phase pipe via the connecting pipe, and to prevent the liquid phase cooling refrigerant from flowing back through the connecting pipe. It is an object of the present invention to provide a cooling device capable of discharging the liquid phase refrigerant in the gas phase pipe into the liquid phase pipe.

In order to solve the above-mentioned problems and achieve the object, the cooling device according to the present invention cools the object to be cooled by evaporating the refrigerant in the liquid phase by heat exchange between the object to be cooled and the refrigerant. The evaporating part and the condensing part which are arranged above the evaporating part and dissipate the heat of the refrigerant to the external fluid by condensing the refrigerant in the gas phase by heat exchange between the refrigerant and the external fluid. A gas phase pipe for guiding the gas phase refrigerant from the evaporating part to the condensing part, a liquid phase pipe for guiding the liquid phase refrigerant from the condensing part to the evaporating part, and the gas phase pipe. A cooling device including a connecting pipe for connecting the liquid phase pipe and the liquid phase pipe, which is provided in the connecting pipe and allows the flow of the refrigerant between the gas phase pipe and the liquid phase pipe to flow. A control valve controlled by changing the opening / closing degree of the flow path in the connecting pipe, and the liquidus phase by reducing the opening / closing degree when the pressure on the liquid phase piping side is higher than the pressure on the gas phase piping side. It is characterized by including a control device for controlling the control valve so that the opening / closing degree is increased when the pressure on the piping side is lower than the pressure on the gas phase piping side.

The cooling device according to the present invention reduces the opening / closing degree of the control valve provided in the connecting pipe when the pressure on the liquid phase pipe side is higher than the pressure on the gas phase pipe side, and is larger than the pressure on the gas phase pipe side. By increasing the degree of opening and closing when the pressure is low, the backflow of the liquid phase cooling refrigerant from the liquid phase pipe to the gas phase pipe via the connecting pipe is suppressed, and the liquid phase in the gas phase pipe is suppressed through the connecting pipe. It has the effect of being able to discharge the refrigerant of the above into the liquid phase piping.

FIG. 1 is a perspective view showing a schematic configuration of a cooling device according to an embodiment. FIG. 2 is a diagram showing the liquid phase refrigerant existing inside the liquid phase pipe and the sub gas phase pipe in the cooling device according to the embodiment. FIG. 3 is a diagram showing an example of the state of the cooling device during high-load operation of the vehicle. FIG. 4 is a diagram showing an example of the state of the cooling device during light load operation of the vehicle. FIG. 5 is a diagram showing the posture of the cooling device when the vehicle descends a slope. FIG. 6 is a graph showing the relationship between the battery temperature and the refrigerant saturation pressure. FIG. 7A is a graph showing the relationship between the amount of heat generated by the battery and the amount of refrigerant circulating. FIG. 7B is a graph showing the relationship between the amount of refrigerant circulating and the height of the liquid column. FIG. 8 is a diagram showing a method of calculating the pressure at the connection portion between the liquid phase pipe and the joint pipe. FIG. 9 is a flowchart showing an example of control performed by the electronic control device in the cooling device according to the embodiment.

Hereinafter, embodiments of the cooling device according to the present invention will be described. The present invention is not limited to the present embodiment.

FIG. 1 is a perspective view showing a schematic configuration of the cooling device 1 according to the embodiment. The cooling device 1 according to the embodiment shown in FIG. 1 adjusts the battery temperature of the assembled battery 2 by cooling the assembled battery 2 mounted on the vehicle as a cooling object. As the vehicle equipped with the cooling device 1, an electric vehicle or a hybrid vehicle that can be driven by a motor (not shown) that uses the assembled battery 2 as a power source is assumed.

The assembled battery 2 has a plurality of rectangular parallelepiped battery cells 21 and a battery temperature sensor 22 that detects the battery temperature, which is the temperature of the battery cells 21. The plurality of battery cells 21 are arranged in the vehicle width direction orthogonal to the vehicle front-rear direction. The battery temperature sensor 22 is provided only for one battery cell 21 of the plurality of battery cells 21, but the battery temperature sensor 22 is provided for each of the plurality of battery cells 21 such as all the battery cells 21. You may. In the present embodiment, the vehicle front-rear direction intersects the vehicle height direction that coincides with the vertical direction when the vehicle is located on a horizontal road surface, and more specifically, is orthogonal to the vehicle height direction. It is one of the directions to do.

The cooling device 1 includes an electronic control device 3, a condenser 11, an evaporator 12, a liquid phase pipe 13, a main gas phase pipe 14, a sub gas phase pipe 15, a connection pipe 16, an on-off valve 17, and the like. It constitutes a refrigerant circuit in which the refrigerant circulates. As the refrigerant that circulates in this refrigerant circuit, the refrigerants used in the vapor compression refrigeration cycle (for example, R134a and R1234yf) are adopted.

The electronic control device 3 is, for example, a device that controls the opening / closing operation of the on-off valve 17, which is a control valve, based on at least the detection result of the battery temperature sensor 22. The electronic control device 3 may also serve as an electronic control device that performs various controls related to the running of the vehicle on which the cooling device 1 is mounted.

FIG. 2 is a diagram showing the liquid phase refrigerant L existing inside the liquid phase pipe 13 and the sub gas phase pipe 15 in the cooling device 1 according to the embodiment.

In the cooling device 1 according to the embodiment, the condenser 11 which is a condensing portion is located on the front side of the vehicle in the front-rear direction of the vehicle. The condenser 11 is a heat exchanger that condenses the gas phase refrigerant evaporated in the evaporator 12. The condenser 11 is arranged in the engine room of the vehicle, for example, and dissipates heat from the gas phase refrigerant by heat exchange with the refrigerant which is the external fluid of the refrigerating cycle device for air conditioning installed in the engine room. Condenses the refrigerant. Further, by arranging the condenser 11 in the engine room of the vehicle, it is possible to effectively utilize the space in the engine room.

In the cooling device 1 according to the embodiment, the evaporator 12 which is an evaporator is located on the rear side of the vehicle in the vehicle front-rear direction. The evaporator 12 is a heat exchanger that exchanges heat between the refrigerant circulating in the evaporator 12 and the assembled battery 2. That is, the evaporator 12 absorbs heat from the assembled battery 2 to the liquid-phase refrigerant L as the refrigerant circulates in the refrigerant circuit, thereby evaporating (boiling and vaporizing) the liquid-phase refrigerant L. The evaporator 12 is thermally conductively connected to the side of the assembled battery 2. Further, the evaporator 12 is arranged below the condenser 11 in the vehicle height direction. As a result, the liquid-phase refrigerant L is accumulated in the lower part of the refrigerant circuit including the evaporator 12 by gravity.

The liquid phase pipe 13 which is a liquid phase passage portion guides the liquid phase refrigerant L condensed in the condenser 11 to the evaporator 12. The end of the liquid phase pipe 13 on the front side of the vehicle in the front-rear direction of the vehicle is connected to the fluid outlet 111 of the condenser 11. The end of the liquid phase pipe 13 on the rear side of the vehicle in the front-rear direction of the vehicle is connected to the fluid inlet portion 121 of the evaporator 12. As a result, a liquid passage for flowing the liquid phase refrigerant L from the condenser 11 to the evaporator 12 is formed inside the liquid phase pipe 13.

The main vapor phase pipe 14 which is the first vapor phase passage portion guides the refrigerant of the vapor phase evaporated by the evaporator 12 to the condenser 11. The main gas phase pipe 14 is inclined uphill toward the front side of the vehicle when viewed from the rear side of the vehicle in the front-rear direction of the vehicle, and extends in the height direction of the vehicle.

The end of the main vapor phase pipe 14 on the rear side of the vehicle in the front-rear direction of the vehicle is connected to the fluid outlet of the evaporator 12. The end of the main gas phase pipe 14 on the front side of the vehicle in the front-rear direction of the vehicle is connected to the condenser 11. As a result, a flow path for flowing the vapor phase refrigerant from the evaporator 12 to the condenser 11 is formed inside the main vapor phase pipe 14.

The sub-gas phase pipe 15 which is the second gas phase passage portion is located above the main gas phase pipe 14, and guides the refrigerant of the gas phase evaporated by the evaporator 12 to the condenser 11. The sub-gas phase pipe 15 is composed of a first pipe portion 151, a second pipe portion 152, a third pipe portion 153, a fourth pipe portion 154, a fifth pipe portion 155, and a sixth pipe portion 156. The first pipe portion 151 is erected above the main gas phase pipe 14 in the vehicle height direction. The second pipe portion 152 extends in the front-rear direction of the vehicle. The third pipe portion 153 is inclined downward to the front side of the vehicle when viewed from the rear side of the vehicle in the front-rear direction of the vehicle, and extends in the height direction of the vehicle. The fourth pipe portion 154 is inclined downward to the front side of the vehicle when viewed from the rear side of the vehicle in the front-rear direction of the vehicle, and extends in the front-rear direction of the vehicle. The fifth pipe portion 155 is inclined uphill toward the front side of the vehicle when viewed from the rear side of the vehicle in the front-rear direction of the vehicle, and extends in the height direction of the vehicle. The sixth pipe portion 156 extends in the front-rear direction of the vehicle.

The lower end of the first pipe portion 151 in the vehicle height direction is connected to the rear end of the main vapor phase pipe 14 in the vehicle front-rear direction. The upper end of the first pipe portion 151 in the vehicle height direction is connected to the rear end of the second pipe portion 152 in the vehicle front-rear direction. The front end of the second pipe portion 152 in the vehicle front-rear direction is connected to the upper end portion of the third pipe portion 153 in the vehicle height direction. The lower end of the third pipe 153 in the vehicle height direction is connected to the rear end of the fourth pipe 154 in the vehicle front-rear direction. The front end of the fourth pipe 154 in the vehicle front-rear direction is connected to the lower end of the fifth pipe 155 in the vehicle height direction. The upper end of the fifth pipe 155 in the vehicle height direction is connected to the rear end of the sixth pipe 156 in the vehicle front-rear direction. The end of the sixth pipe portion 156 on the front side of the vehicle in the front-rear direction of the vehicle is connected to the condenser 11. As a result, a flow path for flowing the vapor phase refrigerant from the evaporator 12 to the condenser 11 is formed inside the sub gas phase pipe 15. In the sub-gas phase pipe 15, the connecting portion between the pipe portions may have an R shape.

Further, in the cooling device 1 according to the embodiment, the first pipe portion 151, the second pipe portion 152, and the third pipe portion 153 of the sub gas phase pipe 15 make the sub gas phase pipe 15 rearward of the vehicle in the vehicle front-rear direction. At the end portion (on one side in the predetermined direction), a tsuno portion 150, which is a rising portion whose at least a part rises above the periphery, is formed. The weapon portion 150 has a convex shape in which the first pipe portion 151 rises upward and then the third pipe portion 153 bends downward via the second pipe portion 152.

In the cooling device 1 according to the embodiment, as shown in FIG. 1, a liquid phase pipe 13, a main gas phase pipe 14, and a sub gas phase pipe 15 are provided on both sides in the vehicle width direction with the assembled battery 2 interposed therebetween. It is arranged separately. Here, when the liquid phase piping 13, the main gas phase piping 14 and the sub gas phase piping 15 are arranged together on only one side in the vehicle width direction of the assembled battery 2, when the liquid phase piping 13, the main gas phase piping 14 and the sub gas phase piping 15 are arranged together on both sides in the vehicle width direction of the assembled battery 2. One of the provided spaces for preventing damage to the assembled battery 2 when a collision in the vehicle width direction occurs in the vehicle becomes a dead space. On the other hand, like the cooling device 1 according to the embodiment, the liquid phase pipe 13, the main gas phase pipe 14, and the sub gas phase pipe 15 are divided into one side each on both sides in the vehicle width direction of the assembled battery 2. By arranging the assembled batteries 2 in the vehicle width direction, both of the spaces provided on both sides in the vehicle width direction can be fully utilized.

The connection pipe 16 is connected to the liquid phase pipe 13 and the sub gas phase pipe 15, and is configured so that the liquid phase refrigerant L in the sub gas phase pipe 15 can be discharged into the liquid phase pipe 13. Further, in the middle of the connecting pipe 16, the flow of the liquid phase refrigerant L between the liquid phase pipe 13 and the sub-gas phase pipe 15 is controlled by changing the degree of opening / closing of the flow path in the connecting pipe 16. An on-off valve 17 which is a control valve is provided.

The first merging portion 191 in which the liquid phase pipe 13 and the connecting pipe 16 are connected and the flow path in the liquid phase pipe 13 and the flow path in the connecting pipe 16 meet is evaporated with the condenser 11 in the vehicle height direction. It is located between the vessel 12 and the vessel 12. Specifically, the first confluence portion 191 is located below the fluid outlet portion 111 of the condenser 11 to which the end portion on the front side of the vehicle is connected in the vehicle height direction and the vehicle front-rear direction of the liquid phase pipe 13. The liquid phase pipe 13 is located above the fluid inlet portion 121 of the evaporator 12 to which the end portion on the rear side of the vehicle is connected in the vehicle front-rear direction.

The second merging portion 192, in which the sub-gas phase pipe 15 and the connecting pipe 16 are connected and the flow path in the sub-gas phase pipe 15 and the flow path in the connecting pipe 16 merge, is the first in the sub-gas phase pipe 15. It is provided at a connecting portion between the end portion on the front side of the vehicle in the vehicle front-rear direction of the four pipe portions 154 and the end portion on the rear side of the vehicle in the vehicle front-rear direction of the fifth pipe portion 155. In the cooling device 1 according to the embodiment, when viewed from the rear side of the vehicle in the front-rear direction of the vehicle, the fourth pipe portion 154 is inclined downward to the front side of the vehicle, and the fifth pipe portion 155 is inclined upward to the front side of the vehicle. It is leaning. Therefore, the second merging portion 192 is located in the recess (valley) of the sub gas phase pipe 15 formed by the fourth pipe portion 154 and the fifth pipe portion 155.

Subsequently, the basic operation of the cooling device 1 according to the embodiment will be described with reference to FIG. In the cooling device 1, when the battery temperature of the assembled battery 2 rises due to self-heating during traveling of the vehicle or the like, the heat of the assembled battery 2 is transferred to the evaporator 12. In the evaporator 12, a part of the liquid phase refrigerant L evaporates by absorbing heat from the assembled battery 2. The assembled battery 2 is cooled by the latent heat of vaporization of the refrigerant existing inside the evaporator 12, and the temperature of the assembled battery 2 is lowered. The refrigerant evaporated in the evaporator 12 flows out from the evaporator 12 to the main vapor phase pipe 14, and moves to the condenser 11 via the main vapor phase pipe 14. In the condenser 11, the liquid-phase refrigerant L condensed by the heat dissipation of the gas-phase refrigerant is lowered by gravity. As a result, the liquid-phase refrigerant L condensed in the condenser 11 flows out from the condenser 11 to the liquid-phase pipe 13, and moves to the evaporator 12 via the liquid-phase pipe 13. Then, in the evaporator 12, a part of the refrigerant L in the inflowing liquid phase evaporates by absorbing heat from the assembled battery 2.

In this way, in the cooling device 1, the refrigerant circulates between the evaporator 12 and the condenser 11 while changing the phase between the gas phase and the liquid phase, and heat is transported from the evaporator 12 to the condenser 11. As a result, the assembled battery 2 to be cooled is cooled. The cooling device 1 has a configuration in which the refrigerant naturally circulates inside the refrigerant circuit even if there is no driving force required for circulating the refrigerant by a compressor or the like. Therefore, the cooling device 1 can realize efficient cooling of the assembled battery 2 while suppressing both power consumption and noise.

Here, in the cooling device 1, a part of the gas phase refrigerant flowing through the sub-gas phase piping 15 from the evaporator 12 side to the condenser 11 side is cooled by outside air or the like as it approaches the condenser 11. It may condense and become the liquid phase refrigerant L. The liquid phase refrigerant L in the sub-gas phase pipe 15 is provided on the rear side of the sub-gas phase pipe 15 in the vehicle front-rear direction, so that the sub-gas phase pipe 15 is provided on the rear side of the sub-gas phase pipe 15 in the vehicle front-rear direction. It cannot be discharged into the evaporator 12 from the end of the pipe, and may stay in the sub-gas phase pipe 15 and block the sub-gas phase pipe 15.

Therefore, in the cooling device 1 according to the embodiment, the liquid staying in the sub-gas phase pipe 15 is formed by connecting the connection pipe 16 to the recess (valley) where the liquid phase refrigerant L tends to accumulate in the sub-gas phase pipe 15. The phase refrigerant L can be efficiently discharged to the liquid phase pipe 13 via the connecting pipe 16. As described above, in the cooling device 1 according to the embodiment, the sub-gas phase pipe 15 provided with the horn portion 150 in which the liquid phase refrigerant L is difficult to be discharged and the liquid phase pipe 13 are connected by the connecting pipe 16. The liquid phase refrigerant L can be discharged to the liquid phase pipe 13 from the sub-gas phase pipe 15 in which the liquid phase refrigerant L is difficult to be discharged.

Further, in the cooling device 1 according to the embodiment, the connection pipe 16 is connected to the liquid phase pipe 13 and the sub gas phase pipe 15 so that the sub gas phase pipe 15 side is higher than the liquid phase pipe 13 side. As a result, the weight of the liquid phase refrigerant L makes it easy to discharge the liquid phase refrigerant L from the sub-gas phase pipe 15 into the liquid phase pipe 13 via the connection pipe 16, and the connection pipe 16 can be connected. It is possible to make it difficult for the liquid phase refrigerant L to flow back from the liquid phase pipe 13 into the sub gas phase pipe 15.

Here, if the liquid phase refrigerant L can always be discharged between the liquid phase pipe 13 and the sub gas phase pipe 15 via the connection pipe 16, the liquid phase refrigerant L in the liquid phase pipe 13 can be discharged. Is likely to flow back into the sub-gas phase pipe 15. In particular, when the pressure on the liquid phase pipe 13 side is higher than the pressure on the sub gas phase pipe 15, the liquid phase refrigerant L enters the sub gas phase pipe 15 from the liquid phase pipe 13 via the connecting pipe 16 due to the pressure difference. Will flow backwards.

Therefore, in the cooling device 1 according to the embodiment, the liquid phase refrigerant L accumulated in the second merging portion 192 of the sub gas phase pipe 15 is discharged to the liquid phase pipe 13 via the connecting pipe 16 according to the necessity. The opening / closing operation of the on-off valve 17 is controlled by the electronic control device 3 according to predetermined conditions. Specifically, the on-off valve 17 reduces the opening / closing degree of the flow path in the connecting pipe 16 when the pressure on the liquid phase pipe 13 side is higher than the pressure on the sub-gas phase pipe 15 side, and reduces the opening / closing degree on the liquid phase pipe 13 side. Is controlled by the electronic control device 3 so as to increase the opening / closing degree when the pressure of the sub-gas phase pipe 15 is lower than the pressure on the sub-gas phase pipe 15 side. In the cooling device 1 according to the embodiment, the on-off valve 17 is closed when the pressure on the liquid phase pipe 13 side is higher than the pressure on the sub gas phase pipe 15, and the pressure on the liquid phase pipe 13 side is on the sub gas phase pipe 15 side. The on-off valve 17 is opened when the pressure is lower than the pressure of.

As a result, when the pressure on the liquid phase pipe 13 side is higher than the pressure on the sub gas phase pipe 15, the liquid phase is prevented from flowing from the liquid phase pipe 13 side to the sub gas phase pipe 15 side. The flow of the liquid phase refrigerant L between the pipe 13 and the sub-gas phase pipe 15 is controlled by the on-off valve 17. When the pressure on the liquid phase pipe 13 side is lower than the pressure on the sub gas phase pipe 15, the liquid phase pipe 13 flows so that the liquid phase refrigerant L flows from the sub gas phase pipe 15 side to the liquid phase pipe 13 side. The flow of the liquid phase refrigerant L between the gas phase pipe 15 and the sub gas phase pipe 15 is controlled by the on-off valve 17. Therefore, in the cooling device 1 according to the first embodiment, the liquid phase cooling refrigerant is suppressed from flowing back from the liquid phase pipe 13 to the sub gas phase pipe 15 via the connecting pipe 16 and stays in the sub gas phase pipe 15. The liquid-phase refrigerant L can be efficiently discharged to the liquid-phase pipe 13 via the connecting pipe 16.

The pressure on the liquid phase pipe 13 side is, for example, the pressure of the first confluence portion 191, specifically, as shown in FIG. 2, the head pressure of the liquid phase refrigerant L in the liquid phase pipe 13. Therefore, the hydraulic column head pressure P at the confluence portion at the position of the first confluence portion 191 between the liquid phase pipe 13 and the connection pipe 16 can be used. The head pressure P of the liquid column at the confluence can be estimated from the liquid level height h1 in the liquid phase pipe 13. The liquid level height h1 is the height from the position at the lowermost end of the liquid phase pipe 13 in the vehicle height direction to the liquid level of the liquid phase refrigerant L in the vehicle height direction. In FIG. 2, the lowermost end of the liquid phase pipe 13 in the vehicle height direction is the end portion of the liquid phase pipe 13 on the vehicle rear side in the vehicle front-rear direction, and the fluid inlet of the evaporator 12 connected to the end portion. The height from the portion 121 to the liquid level is defined as the liquid level height h1. Further, the height H of the connecting portion, which is determined by the configuration of the cooling device 1, is obtained by actually measuring it in advance. The height H of the connection portion is the first of the liquid phase pipe 13 and the connection pipe 16 from the fluid inlet portion 121 of the evaporator 12 connected to the rear end of the vehicle in the vehicle front-rear direction of the liquid phase pipe 13. It is the height in the vehicle height direction up to the confluence 191. Then, the liquid column head pressure corresponding to the liquid column height h2, which is the height obtained by subtracting the connection portion height H from the liquid level height h1, is merged at the position of the first confluence portion 191 in the liquid phase pipe 13. It can be estimated as the head pressure P of the partial liquid column. In the present embodiment, the portion of the liquid phase refrigerant L existing between the first confluence portion 191 and the liquid surface in the vehicle height direction in the liquid phase pipe 13 is referred to as a “liquid column”.

In the liquid phase pipe 13, the head pressure of the liquid column increases as the height of the vehicle becomes lower than the liquid level. On the other hand, the pressure in the condenser 11 is the lowest pressure in the refrigerant circuit. The lowermost portion of the liquid phase pipe 13 is in a state where the pressure is about 1 to several [kPa] higher than that of the fluid inlet portion of the condenser 11 to which the uppermost portion of the sub gas phase pipe 15 is connected. Since the water column water head pressure in the liquid phase pipe 13 decreases from the lowermost end to the uppermost end (condenser 11) side of the liquid phase pipe 13, the pressure in the sub gas phase pipe 15 is equal to or lower than that in the sub gas phase pipe 15. , Exists between the lowermost end and the uppermost end of the liquid phase pipe 13. Therefore, by connecting the connection pipe 16 to the liquid phase pipe 13 at a position higher than the lowermost end of the liquid phase pipe 13, the sub-gas phase pipe 15 is higher than the confluence liquid column head pressure P at the first confluence part 191. It becomes easy to secure a pressure difference between the pressure on the liquid phase pipe 13 side and the pressure on the sub gas phase pipe 15 side so that the pressure inside becomes high. As a result, it is possible to broaden the operating conditions of the vehicle in which the liquid phase refrigerant L in the sub-gas phase pipe 15 is discharged to the liquid phase pipe 13 without backflow.

FIG. 3 is a diagram showing an example of the state of the cooling device 1 during high-load operation of the vehicle. During high-load operation of the vehicle, the electric power output from the assembled battery 2 to the motor is large, so that the amount of heat generated by the battery cell 21 of the assembled battery 2 increases. The liquid level height h1 in the liquid phase pipe 13 increases as the amount of heat generated by the battery increases. Therefore, as shown in FIG. 3, when the liquid level height h1 is significantly higher than that of the first confluence portion 191 of the liquid phase pipe 13 and the connecting pipe 16, "pressure in the sub gas phase pipe 15". There is a possibility that a state satisfying the relationship of <pressure at the first merging portion 191] may occur. Therefore, under the operating conditions of the vehicle in which the relationship of "pressure in the sub-gas phase pipe 15 <pressure at the first confluence 191" is satisfied, the on-off valve 17 is closed and the liquid phase pipe 13 to the sub-gas phase pipe 15 are used. Prevents backflow of refrigerant to. As a result, the increase in pressure loss due to the retention of the liquid phase refrigerant L in the sub-gas phase pipe 15 is reduced, the temperature rise of the battery cell 21 of the assembled battery 2 is suppressed, and the assembled battery 2 (battery cell 21) The life can be improved.

FIG. 4 is a diagram showing an example of the state of the cooling device 1 during light load operation of the vehicle. Since the electric power output from the assembled battery 2 to the motor is small during the light load operation of the vehicle, the amount of heat generated by the battery cell 21 of the assembled battery 2 is reduced. The smaller the amount of heat generated by the battery, the smaller the amount of refrigerant that evaporates in the evaporator 12, and the smaller the amount of refrigerant that circulates. Therefore, a large amount of liquid-phase refrigerant L is stored in the evaporator 12. Therefore, the liquid level height h1 in the liquid phase pipe 13 becomes lower as the amount of heat generated by the battery decreases. Therefore, as shown in FIG. 4, when the liquid level height h1 is lower than the first confluence portion 191 of the liquid phase pipe 13 and the connecting pipe 16 by a distance x, the first in the liquid phase pipe 13 Since the liquid column head pressure does not act at the position of the merging portion 191, the relationship of "pressure in the sub gas phase pipe 15> pressure at the first merging portion 191" is satisfied. Therefore, under the operating conditions of the vehicle that satisfies the relationship of "pressure in the sub-gas phase pipe 15> pressure at the first merging portion 191", the on-off valve 17 is opened and the liquid phase pipe is connected to the sub-gas phase pipe 15. It enables the discharge of the liquid phase refrigerant L to 13.

FIG. 5 is a diagram showing the posture of the cooling device 1 when the vehicle descends a slope. As shown in FIG. 5, the posture of the cooling device 1 when the vehicle descends is inclined with respect to the horizontal direction so that the front side of the vehicle is lower than the rear side of the vehicle in the front-rear direction of the vehicle. In this way, when the cooling device 1 is tilted, the vertical component in the liquid column (the component in the gravity direction of the liquid phase refrigerant L) in the liquid phase pipe 13 decreases, so that the liquid phase pipe 13 and the connecting pipe 16 are connected to each other. The confluence liquid column head pressure P at the position of the first confluence 191 is lower than when the vehicle is located on a horizontal road surface. Therefore, even when the liquid level height h1 is higher than that of the first merging portion 191 of the liquid phase pipe 13 and the connecting pipe 16, "pressure in the sub gas phase pipe 15> pressure at the first merging portion 191". Under the operating conditions of the vehicle that satisfies the relationship of "", the on-off valve 17 is opened to enable the discharge of the liquid phase refrigerant L from the sub-gas phase pipe 15 to the liquid phase pipe 13.

The magnitude of the pressure in the liquid phase pipe 13 can be estimated from the liquid level h1 of the liquid phase refrigerant L. The magnitude of the liquid level height h1 can be predicted from, for example, the inclination of the vehicle body, the battery load of the assembled battery 2, the piping pressure, and the like, and various sensors for acquiring such information may be provided. When the battery load is high, such as the amount of heat generated by the battery cell 21 of the assembled battery 2, the high output of the motor that supplies power from the assembled battery 2, and the high outside temperature, the amount of heat generated by the battery is high. Since the liquid phase refrigerant L is largely vaporized and the internal pressure in the evaporator 12 is high, it is difficult for the liquid phase refrigerant L to enter the evaporator 12 from the liquid phase piping 13, and the liquid level of the liquid phase refrigerant L is high. h1 (liquid column height h2) tends to be high.

FIG. 6 is a graph showing the relationship between the battery temperature and the refrigerant saturation pressure. The horizontal axis in FIG. 6 is the battery temperature of the battery cell 21 of the assembled battery 2. The vertical axis in FIG. 6 is the refrigerant saturation pressure of the refrigerant in the sub-gas phase pipe 15.

The magnitude of the pressure in the sub-gas phase pipe 15 can be estimated as the battery load of the assembled battery 2 from, for example, the battery temperature of the battery cell 21 detected by the battery temperature sensor 22. As shown in FIG. 6, the battery temperature and the refrigerant saturation pressure are in a proportional relationship, and the higher the battery temperature, the higher the refrigerant saturation pressure. Further, there is a proportional relationship between the refrigerant saturation pressure and the pressure in the sub-gas phase pipe 15, and the higher the refrigerant saturation pressure, the higher the pressure in the sub-gas phase pipe 15. From this, since there is a relationship of "pressure in the sub-gas phase pipe 15 ∝ refrigerant saturation pressure ∝ battery temperature", the pressure in the sub-gas phase pipe 15 can be estimated from the battery temperature. Further, if the battery temperature is used as an argument, it is possible to obtain an index that correlates with the pressure in the sub-gas phase pipe 15 instead of the absolute value of the pressure in the sub-gas phase pipe 15.

FIG. 7A is a graph showing the relationship between the amount of heat generated by the battery and the amount of refrigerant circulating. The horizontal axis in FIG. 7A is the amount of heat generated by the battery cell 21 of the assembled battery 2. The amount of heat generated by the battery is calculated using, for example, a voltage value and a current value when power is output from the battery cell 21. The vertical axis in FIG. 7A is the amount of refrigerant circulating in the refrigerant circuit of the cooling device 1. FIG. 7B is a graph showing the relationship between the amount of refrigerant circulating and the height of the liquid column h2. The horizontal axis in FIG. 7B is the amount of refrigerant circulating in the refrigerant circuit of the cooling device 1. The vertical axis in FIG. 7B is the height h2 of the liquid column of the liquid phase refrigerant L in the liquid phase pipe 13.

As shown in FIG. 7A, the battery calorific value and the refrigerant circulation amount are in a proportional relationship, and the larger the battery calorific value, the larger the refrigerant circulation amount. Further, as shown in FIG. 7B, there is a proportional relationship between the refrigerant circulation amount and the liquid column height h2, and the liquid column height h2 increases as the refrigerant circulation amount increases. From this, since there is a relationship of "battery calorific value ∝ refrigerant circulation amount ∝ liquid column height h2", the liquid column height h2 and thus the confluence liquid column head pressure P can be estimated from the battery calorific value. Further, if the battery calorific value is used as an argument, an index correlating with the liquid column height h2 can be obtained. Needless to say, since the liquid level height h1 and the liquid column height h2 in the liquid phase pipe 13 are in a proportional relationship, the liquid level height h1 can be estimated from the amount of heat generated by the battery.

FIG. 8 is a diagram showing a method of calculating the pressure at the first confluence portion 191 in the liquid phase pipe 13. As shown in FIG. 8, the head pressure P of the confluence portion at the first confluence portion 191 in the liquid phase pipe 13 is relative to the liquid column height h2 obtained by subtracting the connection portion height H from the liquid level height h1. Therefore, it is preferable to calculate by considering the inclination angle (inclination angle of the liquid phase pipe 13) θ of the liquid column with respect to the horizontal at the position of the liquid level in the liquid phase pipe 13. As a result, the cooling device 1 is tilted when the vehicle descends, based on the detection result of the vehicle tilt sensor provided on the vehicle, with reference to the tilt angle θ when the vehicle is positioned on the horizontal road surface. The head pressure P of the confluence part liquid column in the posture can be estimated more accurately.

Further, in the cooling device 1 according to the embodiment, the magnitude relationship between the pressure on the liquid phase pipe 13 side and the pressure on the sub gas phase pipe 15 side is the pressure on the liquid phase pipe 13 side and the pressure on the sub gas phase pipe 15 side. It may be estimated from only one of the above. That is, the magnitude relationship between the pressure on the liquid phase pipe 13 side and the pressure on the sub gas phase pipe 15 side is determined based only on the battery calorific value related to the pressure on the liquid phase pipe 13 side (confluence part liquid column water head pressure P). You may estimate. Alternatively, the magnitude relationship between the pressure on the liquid phase pipe 13 side and the pressure on the sub gas phase pipe 15 side may be estimated based only on the battery temperature related to the pressure in the sub gas phase pipe 15.

Further, in the cooling device 1 according to the embodiment, the pressure on the liquid phase pipe 13 side (confluence portion liquid column head pressure P), the liquid level height h1, the pressure in the sub gas phase pipe 15, and the like are directly controlled. A sensor or the like for detecting may be provided.

FIG. 9 is a flowchart showing an example of the control performed by the electronic control device 3 in the cooling device 1 according to the embodiment. In the flowchart shown in FIG. 9, it is assumed that the on-off valve 17 is closed at the start of control.

First, the electronic control device 3 determines whether the sub gas phase pipe 15 is blocked by the liquid phase refrigerant L (step S1). At this time, to determine whether or not the sub-gas phase pipe 15 is blocked by the liquid phase refrigerant L, for example, predetermined determination information such as the number of inclinations of the vehicle and the outside air temperature is detected by a sensor mounted on the vehicle. However, it can be performed based on the detection result. When it is determined that the sub-gas phase pipe 15 is not blocked by the liquid phase refrigerant L (No in step S1), the electronic control device 3 keeps the on-off valve 17 closed (step S8). End a series of controls.

On the other hand, when it is determined that the sub gas phase pipe 15 is blocked by the liquid phase refrigerant L (Yes in step S1), the electronic control device 3 estimates the pressure in the sub gas phase pipe 15 (step S2). ). Next, the electronic control device 3 estimates the liquid column height h2 in the liquid phase pipe 13 (step S3). Next, the electronic control device 3 calculates the pressure of the first confluence portion 191 between the liquid phase pipe 13 and the connection pipe 16 in consideration of the inclination of the vehicle (step S4). Next, the electronic control device 3 determines whether or not the relationship of "pressure in the first merging portion 191 <pressure in the sub gas phase pipe 15" is satisfied (step S5). As described above, the pressure of the first confluence portion 191 corresponds to the head pressure P of the confluence portion liquid column. When it is determined that the relationship of "pressure in the first merging section 191 <pressure in the sub gas phase pipe 15" is not satisfied (No in step S5), the electronic control device 3 maintains the on-off valve 17 closed. Then (step S8), a series of control is terminated.

On the other hand, when it is determined that the relationship of "pressure of the first merging portion 191 <pressure in the sub gas phase pipe 15" is satisfied (Yes in step S5), the electronic control device 3 opens the on-off valve 17 for a predetermined time (yes). Step S6). Next, the electronic control device 3 closes the on-off valve 17 after a lapse of a predetermined time (step S7), and ends a series of controls.

As described above, in the cooling device 1 according to the embodiment, the pressure of the first confluence portion 191 between the liquid phase pipe 13 and the connection pipe 16 is applied to the on-off valve 17 provided in the connection pipe 16 in the sub gas phase pipe 15. It closes when it is higher than the pressure of, and opens when it is lower than the pressure in the sub-gas phase pipe 15. As a result, the liquid phase refrigerant L is suppressed from flowing back from the liquid phase pipe 13 to the sub gas phase pipe 15 via the connection pipe 16, and the liquid phase refrigerant L staying in the sub gas phase pipe 15 is transferred to the sub gas phase pipe 15. It can be efficiently discharged to the liquid phase pipe 13 via the connecting pipe 16.

1 Cooling device 2 Set battery 3 Electronic control device 11 Condenser 12 Evaporator 13 Liquid phase piping 14 Main gas phase piping 15 Sub gas phase piping 16 Connection piping 17 On-off valve 21 Battery cell 22 Battery temperature sensor 151 1st pipe part 152 No. 2 Pipe 153 3rd pipe 154 4th pipe 155 5th pipe 156 6th pipe L Liquid phase refrigerant

Claims (1)

An evaporating part that cools the object to be cooled by evaporating the refrigerant in the liquid phase by heat exchange between the object to be cooled and the refrigerant.
A condensing section that is arranged above the evaporating section and that dissipates the heat of the refrigerant to the external fluid by condensing the refrigerant in the gas phase by heat exchange between the refrigerant and the external fluid.
A gas phase pipe for guiding the refrigerant of the gas phase from the evaporation part to the condensing part, and
A liquid phase pipe for guiding the liquid phase refrigerant from the condensing part to the evaporating part,
A connection pipe connecting the gas phase pipe and the liquid phase pipe,
It is a cooling device equipped with
A control valve provided in the connecting pipe and controlling the flow of the refrigerant between the gas phase pipe and the liquid phase pipe by changing the degree of opening / closing of the flow path in the connecting pipe.
When the pressure on the liquid phase piping side is higher than the pressure on the gas phase piping side, the opening / closing degree is reduced, and when the pressure on the liquid phase piping side is lower than the pressure on the gas phase piping side, the opening / closing degree is reduced. A control device that controls the control valve so as to increase the size of
A cooling device characterized by being provided with.

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