Coolant circuit with valve device for proportional coolant volume distribution and motor vehicle with such a coolant circuit

Abstract

The invention relates to a coolant circuit (10) for an at least partially electrically powered motor vehicle (200), comprising a battery circuit (12) configured to cool at least one energy storage device (14) of the motor vehicle (200); a component circuit (16) configured to cool at least one electric drive (18) of the motor vehicle (200); a first heat exchanger (20), in particular a low-temperature cooler, around which ambient air (UL) flows; a first valve device (22) configured to conduct coolant from the first heat exchanger (20) to the battery circuit (12) and / or the component circuit (16); at least one coolant pump (24) assigned to the battery circuit (12);a second heat exchanger (26), in particular a chiller, which is in thermal communication with the battery circuit (12) and through which a coolant can flow, wherein the second heat exchanger (26) is arranged in the battery circuit (12) downstream of the energy store (14). Provision is made for a second valve device (32) to be arranged in the battery circuit (12) between the energy store (14) and the second heat exchanger (26), which is designed to proportionally direct a coolant volume flow downstream of the energy store (14) to the second heat exchanger (26) and to the coolant pump (24). Furthermore, a motor vehicle (200) with such a coolant circuit (10) is described.

Description

[0001] The invention relates to a coolant circuit for a motor vehicle that is at least partially electrically powered, comprising a battery circuit configured to cool at least one energy storage device of the motor vehicle; a component circuit configured to cool at least one electric drive of the motor vehicle; a first heat exchanger, in particular a low-temperature cooler, surrounded by ambient air; a first valve assembly configured to direct coolant from the heat exchanger to the battery circuit and / or the component circuit; at least one coolant pump associated with the battery circuit; and a second heat exchanger, in particular a chiller, which is in thermal contact with the battery circuit and through which a refrigerant flows, wherein the second heat exchanger is arranged downstream of the energy storage device in the battery circuit.

[0002] Such a coolant circuit is known, for example, from DE 10 2021 113 380 A1. Reference is also made to US 2021 294 643 A1 and DE 10 2018 206 791 A1.

[0003] In the coolant circuits of electric vehicles, switching valves are present in the battery cooling circuit. When the battery is cooled via a chiller, it is not possible to regulate the flow rate distribution between the battery and the chiller. This can lead to high coolant temperatures during battery cooling operation (active battery cooling via chiller). In a refrigeration system integrated via the chiller and operating with R744 (CO2) as the refrigerant, this can result in problematic refrigeration circuit operation due to excessively high suction pressures.

[0004] The object underlying the invention is seen as being to provide a coolant circuit and a motor vehicle in order to avoid the above disadvantages, in particular to enable an optimized thermal interaction between the coolant circuit and the refrigeration system or the refrigerant circuit.

[0005] This problem is solved by a coolant circuit and a motor vehicle with the features of the respective independent patent claim. Advantageous embodiments with expedient further developments are specified in the dependent patent claims.

[0006] A coolant circuit for a motor vehicle that is at least partially electrically powered is proposed, comprising a battery circuit configured to cool at least one energy storage device of the motor vehicle; a component circuit configured to cool at least one electric drive of the motor vehicle; a first heat exchanger, in particular a low-temperature cooler, surrounded by ambient air; a first valve assembly configured to direct coolant from the heat exchanger to the battery circuit and / or the component circuit; at least one coolant pump associated with the battery circuit; and a second heat exchanger, in particular a chiller, thermally connected to the battery circuit and through which a refrigerant flows, wherein the second heat exchanger is arranged downstream of the energy storage device in the battery circuit.It is provided that a second valve device is arranged in the battery circuit between the energy storage unit and the second heat exchanger, which is designed to direct a coolant volume flow downstream from the energy storage unit proportionally to the second heat exchanger and to the coolant pump.

[0007] This makes it possible to reduce the coolant flow rate at the second heat exchanger (chiller) to avoid critical operation of the refrigeration system (excessive suction pressure), while simultaneously ensuring that the coolant flow rate to the energy storage system (high-voltage battery) is not reduced or fails to be too low. Furthermore, this type of valve also maintains other functionalities of the coolant circuit, similar to those of a diverter valve. In particular, it remains possible to purge the energy storage system (high-voltage battery) while the coolant circuit is operating, for example, in a heat pump mode.

[0008] It should be noted that the energy storage unit may also be heated depending on the configuration of the coolant circuit, especially if the battery circuit and the component circuit are interconnected or in fluid contact.

[0009] In the coolant circuit, the second valve assembly can have a valve insert that has two fluidically separated flow sections, wherein a first flow section is designed such that, depending on a valve setting, it is in fluid communication with at least two and at most three valve connections of the second valve assembly.

[0010] In the coolant circuit, the valve insert can have a second flow section, which is designed so that, depending on the valve position, it is in fluid contact with only one valve port and a maximum of two valve ports of the second valve assembly.

[0011] Such a valve insert allows different operating modes to be enabled using a single valve device, whereby bypass functions in particular are provided by means of the second flow section, without the need for separate bypass lines and any valves required for this purpose, such as check valves, throttles or the like, in the coolant circuit or battery circuit.

[0012] In the coolant circuit, the valve insert can have an essentially cylindrical shape with a first recess forming the first flow section and a second recess forming the second flow section.

[0013] The recesses may only be provided on a portion of the total height of the cylindrical valve insert. In particular, the recesses are arranged so that they face the valve ports of the valve assembly.

[0014] In the coolant circuit, approximately 40% to 60% of the cylinder's base area can be cut out in the area of ​​the first recess, relative to an imaginary cross-sectional plane. In particular, the first recess can be semicircular. Depending on the relative rotational position of the valve insert to the valve ports, this allows for different flow cross-sections at the respective valve ports, so that the coolant flow rate can be directed proportionally to each port.

[0015] Furthermore, a motor vehicle with at least a partially electric drive, at least one energy storage device, a refrigeration system and a coolant circuit described above is proposed, wherein the refrigeration system and the coolant circuit are thermally connected to each other by the second heat exchanger, such that coolant directed to the energy storage device can be cooled by means of the second heat exchanger.

[0016] The vehicle may have a control unit configured to regulate the second valve assembly of the battery circuit such that, during active cooling of the energy storage device, the coolant volume routed through the second heat exchanger is adjusted according to a suction pressure detected in the refrigeration system. A portion of the coolant volume not routed through the second heat exchanger is directed to the coolant pump to enable purging of the battery circuit, in particular direct recirculation to the energy storage device. Alternatively or additionally, the temperature of the refrigerant and / or the coolant temperature may also be taken into account.

[0017] The refrigerant circuit described above offers the following advantages in particular. It allows for conversion to the use of refrigerant R744 (CO2). Due to the second valve assembly, only minor modifications to existing circuits and components are required, eliminating the need for additional bypass lines (hoses) and, if necessary, a check valve and restrictor in the bypass line.

[0018] Further advantages and details of the invention will become apparent from the following description of embodiments with reference to the figures. These show: Fig. 1. A simplified and schematic representation of a coolant circuit in a motor vehicle; Fig. 2 a simplified and schematic sectional view of a second valve assembly of a battery circuit in a first valve position; Fig. 3 a simplified and schematic sectional view of the second valve assembly of the battery circuit in a second valve position; Fig. 4 A simplified and schematic sectional view of the second valve assembly of the battery circuit in a third valve position.

[0019] In Fig. Figure 1 shows a simplified and schematic coolant circuit 10 for a motor vehicle 200 that is at least partially electrically powered.

[0020] The coolant circuit 10 includes a battery circuit 12 which is designed to heat or cool at least one energy storage device 14, for example a high-voltage battery, of the motor vehicle 200.

[0021] The coolant circuit 10 also includes a component circuit 16, which is designed to cool at least one electric drive 18 of the motor vehicle 200.

[0022] A first heat exchanger 20, in particular a low-temperature cooler, is integrated into the coolant circuit 10 and is surrounded by ambient air UL. A first valve assembly 22 is arranged downstream of the first heat exchanger 20 with respect to the coolant flow direction. This valve assembly is configured to direct coolant from the first heat exchanger 20 to the battery circuit 12 and / or the component circuit 16.

[0023] The first valve assembly 22 is shown here in simplified form as an octagon. It has four valve ports I to IV, whereby in the coolant circuit 10 the coolant can enter the valve assembly 22 through valve port I or valve port III and then exits at valve ports II and / or IV, depending on the valve setting.

[0024] In this context, it should be noted that switching states of the first valve assembly 22 are also possible in which the first heat exchanger 20 is bypassed (bypass function). The first valve assembly 22 serves in particular to separate or connect the various circuits of the entire coolant circuit 10 or the system as needed (combined circuit). The first heat exchanger 20 can be bypassed or partially bypassed, for example, to regulate the temperature in the component circuit 16.

[0025] The coolant circuit 10 further comprises at least one coolant pump 24 associated with the battery circuit 12. A second heat exchanger 26, in particular a chiller, is arranged in the coolant circuit 10 and is in thermal contact with the battery circuit 12. The second heat exchanger 26 is arranged downstream of the energy storage device 14 in the battery circuit 12.

[0026] The integration of the second heat exchanger 26 into a refrigerant circuit 28 or a refrigeration system of the motor vehicle 200 is indicated by the dashed lines. A third heat exchanger 30, in particular a condenser or gas cooler, is also integrated into the refrigerant circuit 28. In the example shown, the third heat exchanger 30 is arranged downstream of the first heat exchanger or low-temperature cooler of the coolant circuit 10 with respect to the ambient air flow direction UL.

[0027] In the battery circuit 12, a second valve assembly 32 is arranged between the energy storage device 14 and the second heat exchanger 26, which is designed to direct a coolant volume flow downstream from the energy storage device 14 proportionally to the second heat exchanger 26 and to the coolant pump 24.

[0028] The second valve assembly 32 is shown here in simplified form as an octagon. It has four valve ports A to D, whereby in the battery circuit 12 the coolant enters the valve assembly 32 downstream of the energy storage device 14 through valve port A and can then exit at valve ports B and / or C and / or D, depending on the valve setting. Further details of the second valve assembly 32 will be described later with reference to the Fig. 2 and Fig. 3. Describe.

[0029] In the Fig. Figure 1 shows several branches Ab1 to Ab5 for the coolant circuit 10. It should be noted that the arrangement of these branches Ab1 to Ab5 is exemplary and not necessarily restrictive. The representation of branches Ab1 to Ab5 serves in particular to allow for a more detailed description of the topology of the coolant circuit 10 below.

[0030] The following components, for example, can be assigned to the battery circuit 12 within the coolant circuit 10: valve connection IV of the first valve assembly 22, branches Ab2, Ab3, Ab4, coolant pump 24, second heat exchanger 26 (chiller) and second valve assembly 32.

[0031] The following components, for example, can be assigned to the component circuit 16 within the coolant circuit 10: valve connection II of the first valve assembly 22, branches Ab1 and Ab5 and a coolant pump 34.

[0032] Branch Ab1 forms a connection between battery circuit 12 and component circuit 16.

[0033] In the Fig. Figures 2 to 4 show simplified and schematic sectional views of the second valve assembly 32.

[0034] These illustrations show that the four valve ports A, B, C, D open into a cylindrical valve seat 36. The second valve assembly 32 has a valve insert 38 which has two fluidically separated flow sections 40-1, 40-2.

[0035] A first flow section 40-1 is designed such that, depending on a valve setting or a rotational position of the valve insert 38 in the valve seat 36, it is in fluid communication with at least two and at most three valve connections A, B, C, D of the second valve device 32.

[0036] In the example of the Fig. 2 The first flow section 40-1 with the two valve connections B and C is in fluid contact, which is illustrated by the two contour arrows.

[0037] The valve insert 38 has a second flow section 40-2, which is designed such that, depending on the valve position, it is in fluid communication with only one valve port A, B, C, D and a maximum of two valve ports A, B, C, D of the second valve assembly 32.

[0038] In the example of the Fig. 2 The second flow section 40-2 is in fluid contact with the two valve connections A and D, which is illustrated by the curved contour arrow.

[0039] In the example of the Fig. 3 the valve insert 38 is turned or positioned in a different valve position.

[0040] In this valve position, the first flow section 40-1 is connected to the fluid via valve ports A and B. The second flow section 40-2 is connected to the fluid via valve ports C and D.

[0041] In the example of the Fig. 4 the valve insert 38 is turned or positioned in a different valve position.

[0042] In this valve position, the first flow section 40-1 is in fluid contact with valve ports A, B, and D. The second flow section 40-2 is positioned so that it blocks or closes valve port C.

[0043] From the Fig. 4 It is also evident that the valve insert is adjustable with respect to a flow cross-section effective in the direction of the valve ports B and D, so that depending on the rotational position of the valve insert 38 more or less coolant passes through the valve ports B and D.

[0044] An adjustment range for the valve insert 38, in which coolant reaches both valve port B and valve port D, is simplified and illustrated by the dashed lines and the double arrow EB.

[0045] The valve insert 38 has an essentially cylindrical shape with a first recess 42-1 forming the first flow section 40-1 and with a second recess 42-2 forming the second flow section 40-2.

[0046] In the area of ​​the first recess 42-1, with reference to an imaginary or in the Fig. 2 and Fig. 3. The cross-sectional plane formed by the drawing plane excludes approximately 40% to 60% of the base area of ​​the cylinder or the valve seat 36. As can be seen from the Fig. 2 and Fig. As can be seen in Figure 3, the first recess 42-1 can be approximately semicircular.

[0047] The second recess 42-2 is in the Fig. 3 and Fig. 4. Lens-shaped. However, it can also be designed as a kind of bypass channel in the valve insert 38, as is the case in the Fig. 2 is indicated by a dashed line.

[0048] The valve position of the second valve assembly 32 according to Fig. 2 is used, for example, in heat pump operation when heat from the electric drive 18 is to be transferred to the refrigeration circuit 28 via the second heat exchanger 26 (chiller). In this case, the coolant flows from the coolant pump 34 through the electric drive 18 and the first valve assembly 22. Depending on the switching position of the first valve assembly 22, the coolant circulates either via valve connections III and IV, bypassing the first heat exchanger 20 (low-temperature cooler), or via valve connections I and IV, including the first heat exchanger 20. It is also conceivable that heat is transferred from the ambient air UL to the coolant at the first heat exchanger 20 (cooler) and then transferred to the refrigerant at the second heat exchanger 26 (chiller).

[0049] The valve position of the second valve assembly 32 according to Fig. 3 is used, for example, in the active cooling of the energy storage unit 14. In this case, the coolant flows in the battery circuit 12 from the coolant pump 24 to the energy storage unit 14, then through the valve connections A and B of the second valve assembly. The entire coolant volume flow is then routed through the second heat exchanger 26 (chiller) and returns to the coolant pump 24 via branches Ab1, Ab2, Ab3, and Ab4. In other words, in such a configuration, active battery cooling is achieved via the refrigerant circuit 28.

[0050] The valve position of the second valve assembly 32 according to Fig. 4 is used when the coolant flow rate at the second heat exchanger (chiller) needs to be reduced to prevent critical operation of the refrigeration system (excessive suction pressure), while simultaneously ensuring that the coolant flow rate to the energy storage unit 14 (high-voltage battery) is not completely or insufficiently low. Within the indicated setting range EB, the coolant flow rate can be distributed or directed proportionally to the second heat exchanger 26 and the coolant pump 24.

[0051] With renewed reference to Fig.1 It is again pointed out that the invention also relates to a motor vehicle 200 with at least a partially electric drive 18, at least one energy storage device 14, a refrigeration system 28 and a coolant circuit 10 described above, wherein the refrigeration system 28 and the coolant circuit 10 are thermally connected to each other by means of the second heat exchanger 26 (chiller), such that coolant supplied to the energy storage device 14 (high-voltage battery) can be cooled or heated by means of the second heat exchanger 26.

[0052] The motor vehicle 200 can have a control unit 202 which is configured to control the second valve assembly 32 of the battery circuit 12 in such a way that, when the energy storage device 14 is actively cooled, the coolant volume passed through the second heat exchanger 26 is adjusted depending on a suction pressure detected in the refrigeration system 28, whereby a portion of the coolant volume not passed through the second heat exchanger 26 is directed to the coolant pump 24 in order to enable flushing in the battery circuit 12, in particular direct return to the energy storage device 14. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2021 113 380 A1

[0002] US 2021 294 643 A1

[0002] DE 10 2018 206 791 A1

[0002]

Claims

[1] Coolant circuit (10) for a motor vehicle (200) that is at least partially electrically powered a battery circuit (12) designed to cool at least one energy storage device (14) of the motor vehicle (200); a component circuit (16) designed to cool at least one electric drive (18) of the motor vehicle (200), a first heat exchanger (20) surrounded by ambient air (UL), in particular a low-temperature cooler, a first valve assembly (22) which is configured to direct coolant from the first heat exchanger (20) to the battery circuit (12) and / or the component circuit (16), at least one coolant pump (24) assigned to the battery circuit (12); a second heat exchanger (26), in particular a chiller, which is in thermal contact with the battery circuit (12) and through which a refrigerant flows, wherein the second heat exchanger (26) is arranged downstream of the energy storage device (14) in the battery circuit (12), characterized by , that in the battery circuit (12) between the energy storage device (14) and the second heat exchanger (26) a second valve device (32) is arranged, which is designed to direct a coolant volume flow downstream from the energy storage device (14) proportionally to the second heat exchanger (26) and to the coolant pump (24). [2] Coolant circuit (10) according to claim 1, characterized by, that the second valve assembly (32) has a valve insert (38) which has two fluidically separated flow sections (40-1, 40-2), wherein a first flow section (40-1) is designed such that it is in fluid communication with at least two and at most three valve ports (A, B, C, D) of the second valve assembly (32) depending on a valve setting. [3] Coolant circuit (10) according to claim 2, characterized by , that the valve insert (38) has a second flow section (40-2) which is designed such that, depending on the valve position, it is in fluid communication with only one valve port (A, B, C, D) and at most with two valve ports (A, B, C, D) of the second valve assembly (32). [4] Coolant circuit (10) according to claim 2 or 3, characterized by, that the valve insert (38) has an essentially cylindrical shape with a first recess (42-2) forming the first flow section (40-1) and with a second recess (42-2) forming the second flow section (40-2). [5] Coolant circuit (10) according to claim 4, characterized by , that in the area of ​​the first recess (42-1) approximately 40% to 60% of a base area of ​​the cylinder is recessed with reference to an imaginary cross-sectional plane, in particular the first recess (42-1) is semicircular in shape. [6] Motor vehicle (200) with at least a partially electric drive, at least one energy storage device (14), a refrigeration system (28) and a coolant circuit (10) according to one of the preceding claims, wherein the refrigeration system (28) and the coolant circuit (10) are thermally connected to each other by the second heat exchanger (26) in such a way that coolant supplied to the energy storage device (14) can be cooled or heated by means of the second heat exchanger (26). [7] Motor vehicle (200) according to claim 6 with a control unit (202) which is configured to control the second valve assembly (32) of the battery circuit (12) such that, when the energy storage device (14) is actively cooled, the coolant volume passed through the second heat exchanger (26) is adjusted as a function of a suction pressure detected in the refrigeration system (28), wherein a portion of the coolant volume not passed through the second heat exchanger (26) is directed to the coolant pump (24) to enable flushing in the battery circuit (12).

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