Reservoir tank

Abstract

To suppress entrainment of air into cooling water in a reservoir tank connected to a plurality of cooling systems.SOLUTION: A reservoir tank 10 is used in a cooling system for an electric automobile. The reservoir tank 10 has a first chamber 11 and a second chamber 12 partitioned by a partition wall 15, and a third chamber 13. The first chamber 11 has a first inflow port and a first outflow port connected to a first cooling system, and the second chamber 12 has a second inflow port and a second outflow port connected to a second cooling system. Cooling water can move between the first chamber 11 and the second chamber 12 through the third chamber 13. A through hole 16 is provided on the partition wall 15 at a position higher than an upper limit of a water level of the cooling water. In an operation mode in which the cooling water flowing into the first chamber 11 from the first inflow port 21 flows out of the second outflow port 24 through the third chamber 13 and then the second chamber 12, the water level of the cooling water in the first chamber 11 rises, and the cooling water flows from the first chamber 11 to the second chamber 12 also via the through hole 16.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a reservoir tank, and more particularly to a reservoir tank connected to a plurality of cooling systems. [Background technology]

[0002] Reservoir tanks are used in cooling systems for vehicles, for example. The reservoir tank, which is connected to the cooling system (hereinafter also referred to as the "cooling circuit" or "cooling path") of the cooling system, performs functions such as absorbing volume changes caused by the temperature of the coolant and separating air bubbles contained in the coolant. Typically, a cap is provided on the reservoir tank, and the coolant is filled or replenished through the reservoir tank.

[0003] As electric vehicles and hybrid vehicles have come into practical use, the cooling systems of these vehicles have also become more sophisticated, and cooling systems that have multiple cooling circuits connected to a single reservoir tank have come into practical use. For example, Patent Document 1 describes a reservoir tank that can accommodate multiple refrigerants and can switch the flow of refrigerants inside. The reservoir tank prevents refrigerants from different systems from mixing with each other. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-134587 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the reservoir tank of Patent Document 1, as shown in Fig. 9 (Fig. 2 of Patent Document 1), cooling water can be independently passed through the low-temperature cooling system on the left side of the figure and the high-temperature cooling system on the right side of the figure. By providing multiple cooling systems with different temperatures, it is possible to improve the overall cooling efficiency while performing cooling according to the characteristics of the equipment to be cooled. In addition, in the reservoir tank of Patent Document 1, as shown in FIG. 10 (FIG. 7 of Patent Document 1), the cooling water in the high-temperature cooling system on the right side of the figure can be made to flow to the low-temperature cooling system on the left side of the figure. In this mode, the battery can be warmed in cold weather. Note that the numbers in FIG. 9 and FIG. 10 are the same as those in Patent Document 1, and are different from the numbers in the technical description disclosed in this specification.

[0006] However, when the inventors conducted an investigation into the cooling system realized by the reservoir tank of Patent Document 1, they found that the water level in the tank is likely to drop near the cooling water outlet (element 64 in FIG. 10) to the cooling system on the low temperature side on the left side in the operation mode of FIG. 10. When the water level in the tank drops, air is likely to be entrained in the cooling water supplied to the cooling system on the low temperature side, which is undesirable.

[0007] An object of the present invention is to suppress air entrainment into cooling water in a reservoir tank connected to multiple cooling systems. [Means for solving the problem]

[0008] In the technique of Patent Document 1, the first chamber and the second chamber, which are connected to different cooling systems, are separated from each other by a partition wall to prevent the cooling waters at different temperatures from mixing. After careful consideration, the inventor discovered that providing a specific through hole in the partition separating the first and second chambers would allow cooling water to flow between the first and second chambers through the through hole in a specific operating mode, thereby solving the above-mentioned problem, and thus completed the present invention.

[0009] The present invention relates to a reservoir tank used in a cooling system for an electric vehicle including a first cooling system and a second cooling system, the reservoir tank having a first chamber and a second chamber, the first chamber having a first inlet for directing cooling water from the first cooling system into the first chamber and a first outlet for returning the cooling water in the first chamber to the first cooling system, the second chamber having a second inlet for directing cooling water from the second cooling system into the second chamber and a second outlet for returning the cooling water in the second chamber to the second cooling system, the first chamber and the second chamber being separated by a partition so as to be adjacent to each other in the horizontal direction, the reservoir tank further having a third chamber, and the cooling water is transferred between the first chamber and the second chamber through the third chamber. This reservoir tank is configured to allow water and air to move, and upper and lower limits for the cooling water level are set in the reservoir tank. The partition has a through hole at a position higher than the upper limit of the cooling water level. When the outflow of cooling water from the first outlet and the inflow of cooling water from the second inlet are stopped and a cooling water flow is achieved in which the cooling water that flows from the first cooling system into the first chamber through the first inlet passes through the third chamber and then the second chamber and flows into the second cooling system through the second outlet, the cooling water level in the first chamber rises and cooling water flows from the first chamber to the second chamber through the through hole (first invention).

[0010] In the first invention, preferably, a control plate is provided in the second chamber so as to protrude vertically downward from the top surface of the second chamber, and the control plate is provided so as to cover at least the through hole when viewed from the direction perpendicular to the surface of the partition wall (second invention). Furthermore, in the second invention, preferably, the control plate extends at least from the top surface of the second chamber to the lower limit of the water level of the cooling water (third invention). Furthermore, in the second invention, preferably, even if the water level of the second chamber drops when the cooling water flows from the first chamber to the second chamber through the through hole, the control plate extends at least from the top surface of the second chamber to the water level of the second chamber (fourth invention). Furthermore, in the first invention, preferably, the reservoir tank further has a fourth chamber, and is configured so that the cooling water and air can move between the first chamber and the second chamber through the third chamber and the fourth chamber (fifth invention).

[0011] The present invention also relates to a method for operating a cooling system for an electric vehicle equipped with the reservoir tank of the first invention, the method including a first operating mode and a second operating mode, in which in the first operating mode, a cooling water flow for guiding the cooling water from the first cooling system from the first inlet into the first chamber and returning the cooling water in the first chamber from the first outlet to the first cooling system and a cooling water flow for guiding the cooling water from the second cooling system from the second inlet into the second chamber and returning the cooling water in the second chamber from the second outlet to the second cooling system are realized so as to be substantially independent of each other, and in the second operating mode, in addition to a cooling water flow for guiding the cooling water from the first cooling system from the first inlet into the first chamber and flowing out from the first chamber through the third chamber, then through the second chamber, to the second cooling system through the second outlet, a cooling water flow for flowing from the first chamber into the second chamber through the through hole depending on the operating conditions is realized (sixth invention). Effect of the Invention

[0012] According to the reservoir tank (first invention) of the present invention and the operating method of the cooling system (sixth invention) of the present invention, in the first operating mode, the mixing of cooling waters of different temperatures is prevented, while in the second operating mode, the drop in the cooling water level in the second chamber is suppressed, thereby suppressing the entrainment of air into the cooling water.

[0013] Furthermore, in the case of the second aspect of the invention, in the first operating mode, the movement of hot air or cold air between the first chamber and the second chamber, which would otherwise result in a decrease in thermal efficiency, is suppressed. Furthermore, in the case of the third aspect of the invention, the movement of hot or cold air through the through holes in the first operating mode can be reliably prevented, and a decrease in thermal efficiency can be more reliably suppressed. Furthermore, when the fourth invention is adopted, the cooling water flowing from the first chamber to the second chamber through the through hole in the second operating mode flows gently along the control plate into the cooling water in the second chamber, thereby particularly suppressing air entrainment into the cooling water. Furthermore, in the case of the fifth aspect of the invention, it becomes easier to adjust the water level of the cooling water in the second chamber in each operation mode, and entrainment of air into the cooling water is particularly suppressed. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a perspective view of a reservoir tank according to the first embodiment. [Diagram 2] FIG. 2 is a PP cross-sectional view of the reservoir tank of the first embodiment. [Diagram 3] FIG. 2 is a cross-sectional view of the reservoir tank of the first embodiment taken along line XX. [Figure 4] FIG. 2 is a cross-sectional view of the reservoir tank according to the first embodiment taken along line YY. [Diagram 5] FIG. 2 is a ZZ cross-sectional view of the reservoir tank of the first embodiment. [Figure 6] 6 is a PP cross-sectional view showing a coolant flow in the reservoir tank of the first embodiment in a second operation mode. FIG. [Figure 7] 4 is a ZZ cross-sectional view showing a coolant flow in the reservoir tank of the first embodiment in a second operation mode. FIG. [Figure 8] 5 is a schematic diagram showing the flow and water level of the cooling water in the reservoir tank of the first embodiment in a second operation mode. FIG. [Figure 9] FIG. 2 is a cross-sectional view of the reservoir tank of Patent Document 1 (FIG. 2 of Patent Document 1). [Figure 10] FIG. 7 is a cross-sectional view of the reservoir tank of Patent Document 1 (FIG. 7 of Patent Document 1). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, with reference to the drawings, an embodiment of the present invention will be described by taking a reservoir tank provided in a cooling system used in an electric vehicle as an example. The present invention is not limited to the specific embodiment shown below, and can be embodied by modifying the form. The cooling system may be used in a hybrid vehicle.

[0016] The cooling system includes a first cooling system 31 and a second cooling system 32. Each cooling system is a liquid-cooled system, that is, a cooling system in which cooling water is circulated to cool an object to be cooled and dissipate heat. As shown in Fig. 2, in this water-cooled system, the first cooling system 31 and the second cooling system 32 are connected to a common reservoir tank 10, and the first cooling system 31 and the second cooling system 32 are connected to each other through the reservoir tank 10.

[0017] The first cooling system 31 (31a, 31b) is a cooling system used to make the temperature of the coolant higher than that of the second cooling system 32. The first cooling system 31 is typically equipped with a radiator, an electric heater, a heating unit of an air conditioner, a water pump, etc., and the hot water of the first cooling system 31 is used to heat the vehicle interior, for example.

[0018] The second cooling system 32 (32a, 32b) is a cooling system used to keep the temperature of the coolant lower than that of the first cooling system 31. The second cooling system 32 typically includes a radiator, a motor, a battery unit, an inverter, a water pump, etc., and uses the cold water of the second cooling system 32 to cool the battery and the inverter.

[0019] The cooling system is provided with a changeover valve 30 or a diverter valve (not shown) to allow the cooling water flow in the cooling system to operate in different operating modes, for example, the cooling water can operate in a first operating mode as shown in FIG 2, or the cooling water can operate in a second operating mode as shown in FIG 6.

[0020] As shown in FIG. 2, the first cooling system 31 and the second cooling system 32 are configured to exchange heat with each other through a heat exchange system 81. Although not essential, the heat exchange system 81 may have a function of sending heat from the high-temperature first cooling system 31 to the low-temperature second cooling system 32 through a radiator provided in each cooling system. In addition, although not essential, the heat exchange system 81 may have a heat pump function of sending heat from the low-temperature second cooling system 32 to the high-temperature first cooling system 31 using a heat cycle like an air conditioner. For the heat pump function, it is preferable that the heat exchange system includes a compressor, an evaporator, a chiller, etc. For the heat pump function, the device, parts, and piping may be shared with the cooling system of the air conditioner. Due to the action of the heat exchange system 81, the first cooling system 31 and the second cooling system 32 are maintained at their respective preferred operating temperatures, and cooling can be performed with high efficiency.

[0021] A reservoir tank 10 according to a first embodiment will be described. Fig. 1 is a perspective view of the reservoir tank 10. Fig. 2 is a cross-sectional view taken along line PP, Fig. 3 is a cross-sectional view taken along line XX, Fig. 4 is a cross-sectional view taken along line YY, and Fig. 5 is a cross-sectional view taken along line ZZ.

[0022] The reservoir tank 10 of this embodiment is a hollow tank having a substantially rectangular parallelepiped shape. The inside of the tank is partitioned so that small rooms are arranged horizontally. The reservoir tank 10 has a first chamber 11 and a second chamber 12, and further has a third chamber. Although not essential, it may further have a fourth chamber as in this embodiment. The specific shape of the tank is not particularly limited, but reinforcing ribs for increasing the pressure resistance of the tank, stays or bosses for mounting the tank, etc. may be provided. In addition, the reservoir tank 10 may be provided with an inlet for injecting cooling water and a cap for closing the inlet, as necessary.

[0023] The reservoir tank 10 is provided with a first inlet 21, a first outlet 22, a second inlet 23, and a second outlet 24 to allow the exchange of cooling water between the inside and outside of the tank. The first inlet 21 and the first outlet 22 are connected to the first chamber 11. The second inlet 23 and the second outlet 24 are connected to the second chamber 12. Although not required, typically, these inlets and outlets are provided in a vertically lower portion of the reservoir tank 10.

[0024] As shown in FIG. 2, the first inlet 21 provided in the first chamber 11 guides the cooling water from the first cooling system 31 (31b) into the first chamber. The first outlet 22 provided in the first chamber 11 is piped to return the cooling water in the first chamber to the first cooling system 31 (31a). Similarly, the second inlet 23 provided in the second chamber 12 guides the cooling water from the second cooling system 32 (32b) into the second chamber. The second outlet 24 provided in the second chamber 12 is piped to return the cooling water in the second chamber to the second cooling system 32 (32a).

[0025] Within the cooling system, the reservoir tank 10 is piped in this manner, and when the cooling system is operated in a first operating mode described below, as shown in FIG. 2, a cooling water flow F1 is realized in which the cooling water from the first cooling system 31 (31b) is guided from the first inlet 21 into the first chamber 11 and the cooling water in the first chamber 11 is returned from the first outlet 22 to the first cooling system 31 (31a), and at the same time, a cooling water flow F2 is realized in which the cooling water from the second cooling system 32 (32b) is guided from the second inlet 23 into the second chamber 12 and the cooling water in the second chamber is returned from the second outlet 24 to the second cooling system 32 (32a).

[0026] The configuration of each tank chamber of the reservoir tank 10 will be described in detail. The first chamber 11 and the second chamber 12 are separated by a partition wall 15 so as to be adjacent in the horizontal direction. Also, in the reservoir tank 10, cooling water and air are configured to be movable between the first chamber 11 and the second chamber 12 through the third chamber 13. Although not essential, typically as in this embodiment, the reservoir tank 10 further has a fourth chamber 14, and cooling water and air are configured to be movable between the first chamber 11 and the second chamber 12 through the third chamber 13 and the fourth chamber 14. Although not essential, in the form exemplified in this embodiment, the first to fourth chambers are arranged in a “field” shape when viewed from above so as to be separated in the horizontal direction.

[0027] The first chamber 11 and the fourth chamber 14 are adjacent to each other with a first wall 41 therebetween, and the first chamber 11 and the fourth chamber 14 are configured such that air and cooling water can flow back and forth through an air hole 411 and a communication hole 412 provided in the first wall 41. The second chamber 12 and the third chamber 13 are adjacent to each other with a second wall 42 therebetween, and the second chamber 12 and the third chamber 13 are configured such that air and cooling water can flow back and forth through an air hole 421 and a communication hole 422 provided in the second wall 42. The third chamber 13 and the fourth chamber 14 are adjacent to each other with a third wall 43 therebetween, and the third chamber 13 and the fourth chamber 14 are configured such that air and cooling water can flow back and forth through an air hole 431 and a communication hole 432 provided in the third wall 43.

[0028] The air holes 411, 421, 431 are provided at the upper parts of the tank chambers respectively and are air-permeable. On the other hand, the communication holes 412, 422, 432 are provided at the middle to lower parts of the tank chambers respectively and are sized to allow a predetermined flow rate of cooling water to flow through. By providing these air holes and communication holes and connecting the respective tank chambers, the pressures in the respective tank chambers become approximately the same. Also, cooling water can move between the respective tank chambers through the communication holes.

[0029] In the reservoir tank 10, as long as the cooling water and air are configured to be able to move between the first chamber 11 and the second chamber 12 through the third chamber 13, the specific means for connecting these tank chambers is not particularly limited, and such communication may be realized using rubber piping or the like, but using a partition wall and air holes and communication holes is preferable because it simplifies the configuration of the reservoir tank. Also, while a fourth chamber is not essential, providing a fourth chamber and arranging the chambers in a "T" shape as in the above embodiment and connecting them with air holes and communication holes simplifies the configuration of the reservoir tank and is also preferable from the standpoint of the pressure resistance of the tank.

[0030] In the reservoir tank 10, the upper and lower limits of the coolant level are set. That is, the inside of the reservoir tank 10 is filled with coolant up to a predetermined water level, and the space above the water level is filled with air (preferably nitrogen gas). Although not essential, the reservoir tank 10 is typically marked with the upper limit mark (e.g., "MAX") 44 and the lower limit mark (e.g., "min") 45, which are set as the upper limit and the lower limit of the coolant level. The marking may be by means of embossing or the like, or may be by means of a seal or printing. Although not essential, the first inlet 21, the first outlet 22, the second inlet 23, and the second outlet 24 are usually provided below the lower limit mark 45.

[0031] 3, the partition wall 15 separating the first chamber 11 and the second chamber 12 is provided with a through hole 16 at a position higher than the upper limit of the cooling water level (upper limit mark 44). The first chamber 11 and the second chamber 12 communicate with each other through the through hole 16, allowing air and cooling water to pass back and forth. The shape of the through hole 16 is not particularly limited, and may be circular, elliptical, oblong, or rectangular, or may have a shape in which a large number of small holes or slits are arranged in a punched metal shape, a lattice shape, or a blind shape.

[0032] Since the through hole 16 is located at a position higher than the upper limit of the cooling water level, when the cooling water level in the first chamber 11 or the second chamber 12 remains below the upper limit of the water level, the cooling water does not flow between the two chambers through the through hole 16.

[0033] On the other hand, in a second operation mode described later, when the outflow of cooling water from the first outlet 22 and the inflow of cooling water from the second inlet 23 are stopped and the cooling water that flows from the first cooling system 31b through the first inlet 21 into the first chamber 11 flows through the third chamber 13, then the second chamber 12, and flows into the second cooling system 32a through the second outlet 24 (F3), the level of the cooling water in the first chamber 11 rises and reaches the through hole 16, and the cooling water also flows from the first chamber 11 to the second chamber 12 through the through hole 16 (F4). The height and size of the through hole 16 are determined so that such a cooling water flow is realized.

[0034] In addition, the reservoir tank 10 of the above embodiment is provided with a control plate 17 in the second chamber 12 so as to protrude vertically downward from the top surface of the second chamber 12. The control plate 17 is provided so as to cover at least the through hole 16 when viewed from the direction perpendicular to the surface of the partition wall 15. Although not essential, the control plate 17 is preferably disposed substantially parallel to the partition wall 15 and spaced a predetermined distance from the partition wall 15. A preferred distance between the control plate 17 and the partition wall 15 is preferably approximately the vertical dimension of the through hole 16, and more preferably smaller than the vertical dimension of the through hole 16. In addition, it is preferable that the control plate 17 has a free edge at its lower end, while its upper end is integrated with the tank top surface, and both side ends are integrated with the tank side surfaces and the second wall 42.

[0035] Although not essential, in this embodiment, the control plate 17 extends at least from the top surface of the second chamber 12 to the lower limit of the cooling water level (lower limit mark 45). It is particularly preferable that the control plate 17 extends beyond the lower limit mark 45 from the top surface.

[0036] In addition, although not essential, in this embodiment, even if the water level in second chamber 12 drops when cooling water flows from first chamber 11 to second chamber 12 through through hole 16, control plate 17 extends at least from the top surface of the second chamber to the lowered water level in the second chamber. In other words, it is preferable that the height of the lower end of control plate 17 is set so that the lower end of control plate 17 remains submerged in the cooling water in the second chamber even if the water level in second chamber 12 drops.

[0037] The reservoir tank 10 can be manufactured using known plastic molding techniques. Typically, a preform in which the tank is divided into two parts in the upper and lower direction is molded using injection molding, and the molded preforms are integrated by means of welding (vibration welding, hot plate welding, etc.) or the like to manufacture the reservoir tank 10.

[0038] The plastic material constituting the reservoir tank 10 is not particularly limited, but a resin material capable of forming a tank having suitable heat resistance and pressure resistance, particularly a thermoplastic resin material, can be used. For example, polypropylene resin can be used as the plastic material constituting the reservoir tank 10. The plastic material may contain reinforcing fillers or reinforcing fibers.

[0039] The following describes a method of using the reservoir tank 10 and the effects of the reservoir tank 10. As described below, the reservoir tank 10 of the above embodiment can prevent air from being entrained in the cooling water in a reservoir tank connected to a plurality of cooling paths.

[0040] The reservoir tank 10 is used in a cooling system including a first cooling system 31 and a second cooling system 32. As shown in Fig. 2, in this cooling system, the first cooling system 31 and the second cooling system 32 are connected to a common reservoir tank 10, and the first cooling system 31 and the second cooling system 32 are connected through the reservoir tank 10.

[0041] The cooling system is operated by switching between multiple operation modes, and the path through which the cooling water flows changes for each operation mode depending on the operation of the switching valve, valves, and water pump. The cooling system has at least two operation modes, a first operation mode and a second operation mode. The flow of the cooling water in each operation mode is described below.

[0042] The flow of cooling water in the first operation mode is shown in Fig. 2. In the first operation mode, the cooling water flows so that the first cooling system 31 and the second cooling system 32 circulate independently of each other. That is, in the first operation mode, a cooling water flow F1 is realized in which the cooling water from the first cooling system 31 (31b) is guided from the first inlet 21 into the first chamber 11 and the cooling water in the first chamber 11 is returned from the first outlet 22 to the first cooling system 31 (31a), and at the same time, a cooling water flow F2 is realized in which the cooling water from the second cooling system 32 (32b) is guided from the second inlet 23 into the second chamber 12 and the cooling water in the second chamber is returned from the second outlet 24 to the second cooling system 32 (32a).

[0043] In the first operating mode, the second cooling system 32, which is a so-called cold water system, cools the battery, motor, inverter, etc., while heat is transferred from the second cooling system to the first cooling system 31 using a heat pump, and the first cooling system 31, which is a so-called hot water system, is used to release the heat into the atmosphere or to use the heat for heating.

[0044] In the first operating mode, the flow F1 passing through the first chamber 11 and the flow F2 passing through the second chamber 12 are independent, so there is little mutual flow of cooling water between the tank chambers of the reservoir tank 10, and there is also little difference in water level between the tank chambers. Therefore, in the first operation mode, the water level of the cooling water in the first chamber 11 and the second chamber 12 is the initially planned water level, that is, the water level between the upper limit (upper limit mark 44) and the lower limit (lower limit mark 45) of the set cooling water water level. Therefore, in the first operation mode, the water level does not reach the through hole 16.

[0045] Therefore, even if the partition wall 15 has the through hole 16, in the first operation mode, the water levels in the first chamber 11 and the second chamber 12 do not reach the through hole 16, so that the cooling waters of different temperatures do not mix between the first chamber 11 and the second chamber 12. In the first operation mode, the first chamber 11 and the second chamber 12 behave like substantially isolated and independent tank chambers.

[0046] The flow of the cooling water in the second operation mode of the cooling system using the reservoir tank of the above embodiment is shown in Figures 6, 7, and 8. As shown in Figure 6, in the second operation mode, the outflow of the cooling water from the first outlet 22 and the inflow of the cooling water from the second inlet 23 are stopped, and the cooling water flow F3 is realized such that the cooling water flowing into the first chamber 11 from the first cooling system 31b through the first inlet 21 passes through the fourth chamber 14, the third chamber 13, and then the second chamber 12, and flows out to the second cooling system 32a through the second outlet 24. In this operation mode, the cooling water of the hot water system can be led to the battery of the cold water system, making it possible to warm the battery in cold weather.

[0047] When this flow F3 occurs, the tank chambers are connected by the air holes 411, 421, and 431, and the internal pressures of the tank chambers are equal, so that a water level difference occurs between the tank chambers in response to the water flow resistance of the cooling water passing through the communication holes 412, 422, and 432. As a result, as shown in FIG. 8, the water level in each chamber decreases as the cooling water flows from the first chamber 11 to the fourth chamber 14, the third chamber 13, and the second chamber 12. In FIG. 8, the chambers are illustrated in the order of the flow F3, and the water level of each chamber is shown. Compared to the water levels of each chamber in the first operation mode (water levels indicated by W0 in FIGS. 3 to 5), in the second operation mode, the water level in the first chamber 11 (water level indicated by W1 in FIG. 8) is higher, and the water level in the second chamber 12 (water level indicated by W2 in FIG. 8) is lower. Since the water level difference between each chamber is roughly proportional to the magnitude of the water flow resistance, in the second operating mode, when the cooling water flow rate is increased, the water flow resistance increases and the water level difference between each chamber becomes larger, causing the water level W1 in the first chamber 11 to exceed the upper limit 44 of the normal cooling water level, and the water level W2 in the second chamber 12 to fall below the lower limit 45 of the normal cooling water level.

[0048] In the technology described in Patent Document 1, the first chamber and the second chamber are isolated from each other, so the inventors have found that when the cooling water flow rate in the second operation mode is increased, the water level W2 in the second chamber 12 drops as the water level W1 in the first chamber 11 rises. When the water level W2 in the second chamber 12 drops, air in the second chamber is easily entrained when the cooling water in the second chamber 12 flows from the second outlet 24 to the second cooling system 32a. If air is sent to the cooling system, the efficiency of heat exchange decreases. Therefore, in the technology described in Patent Document 1, there is a restriction that it is difficult to increase the cooling water flow rate in the second operation mode in order to avoid entrainment of air.

[0049] In the reservoir tank 10 of the above embodiment, the through hole 16 is provided in the partition wall 15 separating the first chamber 11 and the second chamber 12 at a position higher than the upper limit of the water level of the cooling water (upper limit mark 44). In the second operation mode, when the flow rate of the cooling water increases, the water level W1 in the first chamber increases, and the water level W1 reaches the height at which the through hole 16 is provided. Then, the cooling water flows from the first chamber 11 to the second chamber 12 through the through hole 16 (flow indicated by F4). That is, in the second operation mode, in addition to the cooling water flow F3 in which the cooling water from the first cooling system 31 is guided from the first inlet into the first chamber 11, and the cooling water flows from the first chamber 11 through the third chamber 13, then through the second chamber 12, and flows out to the second cooling system 32 through the second outlet, a cooling water flow F4 in which the cooling water flows from the first chamber 11 through the through hole 16 into the second chamber 12 is realized under an operation condition in which the flow rate is large. This flow F4 alleviates the rise in the water level W1 in the first chamber and the fall in the water level W2 in the second chamber 12 when the flow rate is increased, and prevents the water level W2 in the second chamber from falling too low. Therefore, when the cooling water in the second chamber 12 flows from the second outlet 24 to the second cooling system 32a, it is difficult for air in the second chamber to be drawn in.

[0050] In other words, according to the reservoir tank 10 of the above embodiment, in the first operating mode, cooling water of different temperatures is prevented from mixing between the first chamber 11 and the second chamber 12, while in the second operating mode, a drop in the cooling water level in the second chamber is prevented, thereby suppressing the entrainment of air into the cooling water.

[0051] Furthermore, as in the reservoir tank 10 of the above embodiment, when the control plate 17 is provided in the second chamber 12 so as to protrude vertically downward from the top surface of the second chamber 12 and the control plate 17 is provided so as to cover at least the through hole 16 when viewed from the direction perpendicular to the surface of the partition wall 15, the movement of hot air or cold air between the first chamber and the second chamber, which would result in a decrease in thermal efficiency, is suppressed in the first operation mode. From the viewpoint of suppressing the movement of hot air, it is preferable that the control plate 17 is disposed approximately parallel to the partition wall 15 and spaced a predetermined distance from the partition wall 15, and further, it is preferable that the distance between the control plate 17 and the partition wall 15 is approximately the vertical dimension of the through hole 16, and it is particularly preferable that the distance is smaller than the vertical dimension of the through hole 16.

[0052] Furthermore, when the control plate 17 is configured to extend at least from the top surface of the second chamber to the lower limit 45 of the cooling water level, the movement of hot air or cold air through the through holes 16 in the first operation mode can be reliably prevented, and a decrease in thermal efficiency can be more reliably suppressed. From the viewpoint of reliably preventing the movement of hot air or cold air, it is preferable that the lower end of the control plate 17 is a free edge, while the upper end is integrated with the tank top surface and both side ends are integrated with the tank side surfaces and the second wall 42.

[0053] Furthermore, in the second operation mode, when the cooling water flows from the first chamber 11 to the second chamber 12 through the through hole 16 (flow F4), even if the water level W2 in the second chamber drops, if the control plate 17 is configured to extend at least from the top surface of the second chamber to the water level W2 in the second chamber, the entrainment of air into the cooling water is particularly suppressed. This is because the cooling water flow F4 flowing from the first chamber 11 to the second chamber 12 through the through hole 16 in the second operation mode flows quietly along the control plate 17 into the cooling water remaining in the second chamber as shown in Fig. 7, making it difficult for air to be entrained into the cooling water.

[0054] Furthermore, although not required, if the reservoir tank 10 further has a fourth chamber 14 as in the above embodiment, and is configured so that cooling water and air can move between the first chamber 11 and the second chamber 12 through the third chamber 13 and the fourth chamber 14, the degree of freedom in setting the position and size of the communicating holes 412, 422, 432 is increased, making it easier to adjust the water level W2 of the cooling water in the second chamber 12 in each operating mode, and particularly easy to suppress air being entrained in the cooling water.

[0055] The invention is not limited to the above-mentioned embodiment, and can be practiced with various modifications. Other embodiments of the invention will be described below, but in the following description, the differences from the above-mentioned embodiment will be mainly described, and detailed descriptions of similar parts will be omitted. In addition, these embodiments can be practiced by combining parts with each other or by replacing parts.

[0056] In the above embodiment, the reservoir tank 10 is not provided with a coolant inlet or a cap, but the reservoir tank may be provided with a coolant inlet or a cap as necessary. Alternatively, the reservoir tank may be integrated with a pressure release valve as necessary.

[0057] The overall shape of the reservoir tank 10 is not particularly limited, and may be a rectangular parallelepiped, cylindrical, spherical, etc., as long as the required pressure resistance is obtained. The number of tank chambers provided in the reservoir tank may be three or more, and preferably four tank chambers are provided in a "T" shape, but the number of tank chambers may be five, six, or more.

[0058] The cooling system in which the reservoir tank 10 is used is typically used for cooling systems using batteries and motors, such as hybrid cars and electric cars, but the specific applications are not limited thereto. The cooling system can also be used for systems including batteries and motors, for example, cooling systems for work vehicles such as cranes, power shovels, and bulldozers, and for mobile bodies such as ships, submarines, and aircraft. The cooling system can also be used for cooling systems for auxiliary battery systems in natural energy power generation facilities, such as solar cell power generation systems and wind power generation systems, and cooling systems for auxiliary power sources installed in substations, power plants, data centers, and the like. [Industrial Applicability]

[0059] The reservoir tank 10 can be used, for example, in the cooling system of an electric vehicle, and is highly industrially applicable. [Explanation of symbols]

[0060] 10 Reservoir Tank 11 Room 1 12 Room 2 13 Room 3 14 Room 4 15 Bulkhead 16 Through holes 17 Control Board 21 1st inlet 22 1st outlet 23 2nd inlet 24 2nd outlet 30 Switching valve 31 1st cooling system 32 Second cooling system 41 1st wall 42 Second wall 43 Third wall 411,421,431 Air hole 412,422,432 Communication hole 44 Upper water level mark 45 Lower water level mark 81 Heat Exchange System

Claims

1. A reservoir tank for use in a cooling system for an electric vehicle including a first cooling system and a second cooling system, The reservoir tank has a first chamber and a second chamber. The first chamber has a first inlet for introducing the cooling water from the first cooling system into the first chamber, and a first outlet for returning the cooling water in the first chamber to the first cooling system, the second chamber has a second inlet for introducing the cooling water from the second cooling system into the second chamber, and a second outlet for returning the cooling water in the second chamber to the second cooling system; The first chamber and the second chamber are separated by a partition so as to be adjacent to each other in a horizontal direction, The reservoir tank further has a third chamber, and is configured so that the cooling water and the air can move between the first chamber and the second chamber through the third chamber. The reservoir tank has upper and lower limits for the coolant level. The partition wall is provided with a through hole at a position higher than the upper limit of the cooling water level, When the outflow of cooling water from the first outlet and the inflow of cooling water from the second inlet are stopped, and a cooling water flow is realized in which the cooling water that has flowed from the first cooling system into the first chamber through the first inlet passes through the third chamber, then the second chamber, and flows out into the second cooling system through the second outlet, The water level of the cooling water in the first chamber rises, and the cooling water flows from the first chamber to the second chamber through the through hole. Reservoir tank.

2. A control plate is provided in the second chamber so as to protrude vertically downward from a top surface of the second chamber, The control plate is provided so as to cover at least the through hole when viewed from a direction perpendicular to the surface of the partition wall. The reservoir tank according to claim 1 .

3. The control plate extends at least from the top surface of the second chamber to the lower limit of the water level of the cooling water. The reservoir tank according to claim 2 .

4. When the cooling water flows from the first chamber to the second chamber through the through hole, even if the water level in the second chamber drops, the control plate extends at least from the top surface of the second chamber to the water level in the second chamber.

3. The reservoir tank according to claim 2.

5. The reservoir tank further has a fourth chamber, and is configured so that cooling water and air can move between the first chamber and the second chamber through the third chamber and the fourth chamber. The reservoir tank according to claim 1 .

6. A method for operating a cooling system for an electric vehicle having the reservoir tank according to claim 1, comprising the steps of: The operating method includes a first operating mode and a second operating mode, In the first operating mode, a cooling water flow that introduces the cooling water from the first cooling system into the first chamber through the first inlet and returns the cooling water in the first chamber to the first cooling system through the first outlet; A cooling water flow that introduces the cooling water from the second cooling system into the second chamber through the second inlet and returns the cooling water in the second chamber to the second cooling system through the second outlet. are realized as flows that are substantially independent of each other, In the second operating mode, A cooling water flow is provided such that the cooling water from the first cooling system is introduced into the first chamber from the first inlet, and the cooling water flows from the first chamber through the third chamber, then through the second chamber, and flows out of the third chamber into the second cooling system through the second outlet; A cooling water flow is realized in which the cooling water flows from the first chamber through the through hole to the second chamber depending on the operating conditions. How to operate the cooling system.

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