Cooling circuit, vehicle cooling system and vehicle

Abstract

The present disclosure relates to a cooling circuit (1) for cooling an electric drive (10) of a vehicle, comprising: a cooling pump (2) for driving circulation of a coolant within the cooling circuit (1); a heat exchanger (3) configured so that the coolant exchanges heat when flowing through the heat exchanger (3); a main branch (4) configured to direct the coolant flowing out of the cooling pump (2) to flow into the electric drive (10) via the heat exchanger (3) when an ambient temperature is higher than a threshold temperature; and a bypass branch (5) configured to direct the coolant flowing out of the cooling pump (2) to flow into the electric drive (10) when the ambient temperature is lower than the threshold temperature. The present disclosure also relates to a vehicle cooling system comprising such a cooling circuit (1) and to a vehicle comprising such a vehicle cooling system.

Description

Technical Field

[0001] This disclosure relates to a cooling circuit for cooling an electric drive unit of a vehicle. This disclosure also relates to a vehicle cooling system including such a cooling circuit and a vehicle including such a vehicle cooling system. Background Technology

[0002] The electric drive system of a vehicle converts electrical energy into the mechanical energy required for vehicle movement. It includes a motor, gearbox, and power electronics. Due to limitations in physical laws and manufacturing processes, the energy transfer efficiency of the components in the electric drive system cannot reach 100%, and heat generation is always present. The vehicle cooling system is used to cool the electric drive system, preventing performance degradation or system failure caused by heat accumulation. The vehicle cooling system can arrange the electric drive system in a cooling circuit. Driven by a cooling pump, a cooling medium circulates in the cooling circuit, carrying away the heat generated by the electric drive system. A heat exchanger is also arranged in the cooling circuit. As the circulating cooling medium flows through the heat exchanger, it exchanges heat with other working fluids such as water or air to dissipate the heat carried away from the electric drive system. In addition to its cooling effect, the cooling medium typically has a low viscosity, which lubricates the moving parts (such as the motor and gearbox) as it flows through the electric drive system, improving its efficiency.

[0003] When vehicles are used in extremely cold environments, the temperature of the cooling medium is relatively low, and it is further cooled as it flows through the heat exchanger, causing the temperature to continue to drop. However, the viscosity of the coolant increases as the temperature decreases. In the heat exchanger, the coolant typically needs to flow through tortuous, narrow cooling pipes to increase the heat exchange area. With the increase in viscosity, the coolant pressure drops significantly at the heat exchanger, resulting in insufficient coolant flow in the cooling circuit. This makes it difficult to meet the lubrication requirements of the electric drive unit, leading to a decrease in the efficiency of the electric drive unit. Using a cooling pump with a larger pumping capacity can alleviate the problem of insufficient coolant flow to some extent, but this increases costs. Summary of the Invention

[0004] Therefore, this disclosure aims to solve the above-mentioned problems, and its purpose is to provide a cooling circuit to solve the above-mentioned technical problems, which can maintain the flow of coolant in cold weather, maintain the efficiency of the electric drive device, and avoid the increase in cost.

[0005] The objective is achieved by a cooling circuit for cooling an electric drive unit of a vehicle according to an embodiment of the present disclosure, the cooling circuit including a cooling pump for driving coolant to circulate within the cooling circuit; a heat exchanger configured to allow the coolant to exchange heat as it flows through the heat exchanger; a main branch configured to guide coolant flowing from the cooling pump into the electric drive unit via the heat exchanger when the ambient temperature is above a threshold temperature; and a bypass branch configured to guide coolant flowing from the cooling pump into the electric drive unit when the ambient temperature is below the threshold temperature.

[0006] In this disclosure, the cooling circuit includes a main branch and a bypass branch. A heat exchanger is arranged in the main branch, while the bypass branch bypasses the heat exchanger. Coolant flowing in the bypass branch does not pass through the heat exchanger. When the ambient temperature is below a threshold, the coolant flow path from the cooling pump to the electric drive unit switches from the main branch to the bypass branch, no longer passing through the heat exchanger and no longer experiencing the pressure drop that would reduce flow rate. Therefore, in extremely cold environments, the cooling circuit according to this disclosure can maintain coolant flow rate to meet the lubrication requirements of the electric drive unit without using a high-specification cooling pump. Furthermore, in such extremely cold environments, the electric drive unit's own heat dissipation capacity is sufficient to meet the cooling requirements, and the coolant bypassing the heat exchanger will not cause the electric drive unit to overheat.

[0007] The cooling circuit according to this disclosure may also have one or more of the following features, individually or in combination.

[0008] According to one embodiment of this disclosure, the electric drive device includes a housing, on which the cooling pump and the heat exchanger are mounted, and wherein at least a portion of the main branch is integrated into the housing, and / or wherein at least a portion of the bypass branch is integrated into the housing. Integrating the main branch and bypass branch into the housing simplifies the assembly steps of the cooling circuit and reduces the volume occupied by the cooling circuit.

[0009] According to one embodiment of this disclosure, the housing includes a shell and a cover assembled together, the cooling pump is mounted on the shell, and the heat exchanger is mounted on the cover.

[0010] According to one embodiment of this disclosure, the housing is provided with a cooling pump mounting cavity, the main branch and the bypass branch open toward the cooling pump mounting cavity, a portion of the cooling pump is accommodated within the cooling pump mounting cavity, a first outlet of the cooling pump is disposed on this portion and communicates with the main branch, and a second outlet of the cooling pump is disposed on this portion and communicates with the bypass branch. Thus, communication with the main branch and the bypass branch is completed when the cooling pump is installed into the cooling pump mounting cavity, eliminating the need for a dedicated communication step and additional connecting components.

[0011] According to one embodiment of this disclosure, the main branch and the bypass branch include a common section disposed on the cover, and in the coolant flow direction, the common section is disposed downstream of the heat exchanger.

[0012] According to one embodiment of the present disclosure, the main branch further includes a first main branch section disposed on the housing, wherein, in the coolant flow direction, the first main branch section is disposed upstream of the heat exchanger.

[0013] According to one embodiment of this disclosure, the main branch further includes a second main branch section and a third main branch section disposed on the cover, wherein, in the coolant flow direction, the second main branch section is disposed between the first main branch section and the heat exchanger, and the third main branch section is disposed between the heat exchanger and the common section. The second and third main branch sections allow the first main branch section to be independent of direct connection to the heat exchanger, and the heat exchanger to be independent of direct proximity to the common section, increasing the design flexibility of the cooling circuit.

[0014] According to one embodiment of this disclosure, the bypass branch further includes a first bypass branch section disposed on the housing, wherein, in the coolant flow direction, the first bypass branch section is disposed upstream of the common section.

[0015] According to one embodiment of this disclosure, the bypass branch further includes a second bypass branch section disposed on the cover, wherein, in the coolant flow direction, the second bypass branch section is disposed between the first bypass branch section and the common section. The second bypass branch section eliminates the need for the first bypass branch section to be directly connected to the common section, increasing the design flexibility of the cooling circuit.

[0016] According to one embodiment of this disclosure, the housing includes a first housing conduit forming at least a portion of the first main branch section, the first housing conduit being in fluid communication with a first outlet of the cooling pump, and the cover includes a first cover conduit, a second cover conduit, and a third cover conduit, the first cover conduit forming at least a portion of the second main branch section and in fluid communication with the first housing conduit and the heat exchanger, the second cover conduit and the third cover conduit being in fluid communication with each other forming at least a portion of the third main branch section, the second cover conduit being in fluid communication with the heat exchanger, and the third cover conduit being in fluid communication with the common section.

[0017] According to one embodiment of this disclosure, the cover further includes a fourth cover pipe and a fifth cover pipe that are in fluid communication with each other forming the common section, the fifth cover pipe being connected to the coolant inlet of the electric drive device, wherein the third cover pipe is in fluid communication with the fourth cover pipe.

[0018] According to one embodiment of this disclosure, the housing includes a second housing conduit forming the first bypass branch section, the second housing conduit being in fluid communication with a second outlet of the cooling pump, and the cover includes a sixth cover conduit forming the second bypass branch section, the sixth cover conduit being in fluid communication with the second housing conduit and the common section.

[0019] According to one embodiment of this disclosure, the cover further includes a fourth cover pipe and a fifth cover pipe that are in fluid communication with each other forming the common section, the fifth cover pipe being connected to the coolant inlet of the electric drive device, wherein the sixth cover pipe is in fluid communication with the fourth cover pipe.

[0020] According to one embodiment of this disclosure, the threshold temperature is between -25°C and -35°C.

[0021] According to one embodiment of this disclosure, the threshold temperature is -30°C.

[0022] This disclosure also relates to a vehicle cooling system that includes the cooling circuit described above.

[0023] This disclosure also relates to a vehicle that includes the vehicle cooling system described above. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The following drawings are not intentionally drawn to scale to actual size; their focus is on illustrating the main points of this disclosure.

[0025] Figure 1 An electric drive device is shown, which includes a cooling circuit according to an embodiment of the present disclosure;

[0026] Figure 2 A block diagram of the cooling circuit is shown;

[0027] Figure 3 A cross-sectional view of the electric drive device is shown, in which a portion of the main branch of the cooling circuit is shown;

[0028] Figure 4 Cross-sectional views of the electric drive unit at different locations are shown, illustrating the bypass branches of the cooling circuit;

[0029] Figure 5 and Figure 6 The housing of the electric drive device is shown;

[0030] Figure 7 The cooling pump of the cooling circuit is shown;

[0031] Figure 8 and Figure 9 The cover of the electric drive device is shown.

[0032] In all the accompanying drawings, the same or similar parts are indicated by the same number. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings.

[0034] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure pertains. The use of terms such as “a,” “an,” or “the” in this patent application specification and claims does not indicate a limitation of quantity, but rather indicates the presence of at least one. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms “upstream” and “downstream” are defined relative to the flow direction of the coolant.

[0035] For ease of description, the accompanying drawings of this disclosure have correspondingly simplified or omitted components commonly used in the art, such as external connecting lines and other components unrelated to the description of this disclosure. These omitted or simplified components do not affect a person skilled in the art's understanding of the content of this disclosure.

[0036] Figure 1 A block diagram of an electric drive device 10 according to an embodiment of the present disclosure is shown. Figure 2 A block diagram of a cooling circuit 1 for cooling the electric drive device 10 is shown.

[0037] The electric drive unit 10 may include, for example, a motor, a gearbox, and power electronics. The motor converts input electrical energy into rotational mechanical energy. The gearbox is mechanically connected to the motor, regulating the torque and speed generated by the motor and further transmitting this energy to the vehicle's wheels. The power electronics may include at least one of an inverter, an on-board charger, and a DC-DC converter. The inverter can be used to convert the DC power output from an energy storage device (such as a battery or other energy storage device) into AC power suitable for driving the motor. The on-board charger is used to charge the energy storage device. The DC-DC converter can convert the high-voltage DC power output from the energy storage device into low-voltage DC power suitable for use in the vehicle's low-voltage system.

[0038] like Figure 1 As shown, the electric drive device 10 includes a housing 11. The housing 11 is formed by assembling a casing 12 and a cover 13 together. The housing 11 may be integrally formed, defining multiple chambers to house a motor, a gearbox, and / or power electronics. The housing 11 may also be assembled from multiple housing assemblies; for example, a housing assembly housing the motor 3 and a housing assembly housing the gearbox 4 may be fixedly connected, for example, with screws to form the housing 11, with a sealing wall provided between the two housings. Specifically, in… Figure 1 In the embodiment shown, housing 11 is an integrated shared housing for the motor and gearbox.

[0039] The electric drive unit 10 is cooled by the cooling circuit 1. (Reference) Figure 2 The cooling circuit 1 includes a cooling pump 2 (e.g., an electric oil pump) for driving the coolant to circulate within the cooling circuit 1, a heat exchanger 3 in which the coolant exchanges heat, and a main branch 4 and a bypass branch 5 for guiding the coolant from the cooling pump 2 into the electric drive unit 10.

[0040] The coolant in cooling circuit 1, such as cooling oil, can exchange heat with water, airflow, or other heat transfer media in heat exchanger 3, dissipating heat and lowering the temperature. Within the electric drive unit 10, the coolant contacts and cools the motor, gearbox, and / or power electronics, and also lubricates moving parts (e.g., the motor and gearbox) within the electric drive unit 10. The coolant within the electric drive unit 10 can return to the cooling pump 2 through the circulation section 7 of cooling circuit 1, and be pumped back to the electric drive unit 10 by the cooling pump 2 via the main branch 4 or bypass branch 5, thus circulating within cooling circuit 1.

[0041] When the vehicle is operating in extremely cold environments, the heat dissipation capacity of the electric drive unit 10 itself is sufficient to meet the cooling requirements. The additional heat dissipation capacity provided by the heat exchanger 3 is no longer necessary. Instead, the heat exchanger 3 hinders the circulation of coolant within the cooling circuit 1. Specifically, the viscosity of the coolant increases at low temperatures. This high-viscosity coolant encounters significant resistance as it flows through the meandering, relatively narrow coolant channels (designed to increase the heat exchange area) within the heat exchanger 3, resulting in a decrease in pressure and flow rate. When the coolant flow rate decreases to a certain extent, the electric drive unit 10 may experience a decrease in efficiency due to insufficient lubrication.

[0042] Therefore, the cooling circuit 1 according to this disclosure provides the ability to operatively bypass the heat exchanger 3. For example... Figure 2 As shown, heat exchanger 3 is arranged on main branch 4, while bypass branch 5 bypasses heat exchanger 3. When coolant flows from cooling pump 2 into electric drive unit 10 via main branch 4, coolant 2 flows through heat exchanger 3; when coolant flows from cooling pump 2 into electric drive unit 10 via bypass branch 5, coolant 2 no longer flows through heat exchanger 3. When the ambient temperature is above the threshold temperature, coolant flows from cooling pump 2 into electric drive unit 10 via main branch 4; when the ambient temperature is below the threshold temperature, coolant flows from cooling pump 2 into electric drive unit 10 via bypass branch 5, thus avoiding the resistance generated by heat exchanger 3. The threshold temperature can be between -25°C and -35°C, and is preferably -30°C. Therefore, even in extremely cold environments, cooling circuit 1 can ensure sufficient coolant flow within electric drive unit 10, maintaining the efficiency of electric drive unit 10 without the need to replace it with a more expensive, high-specification cooling pump.

[0043] Continue to refer to Figure 2 The main branch 4 and bypass branch 5 of the cooling circuit 1 include a common section 6, which is arranged downstream of the heat exchanger 3 in the direction of coolant flow. The coolant flowing in the main branch 4 and bypass branch 5 flows into the interior of the electric drive unit 10 through this common section 6.

[0044] The main branch 4 also includes a first main branch section 41, a second main branch section 42, and a third main branch section 43. The coolant flows into the heat exchanger 3 in the main branch 4 through the first main branch section 41 and the second main branch section 42 in sequence, and the coolant flowing out of the heat exchanger 3 flows into the common section 6 through the third branch section 43.

[0045] The bypass branch 5 also includes a first bypass branch section 51 and a second bypass branch section 52. The coolant flows into the common section 6 in the bypass branch 5, passing sequentially through the first bypass branch section 51 and the second bypass branch section 52.

[0046] It is conceivable that in the main branch 4, the heat exchanger 3 can be directly connected to the first main branch section 41 upstream and directly connected to the common section 6 downstream, thus eliminating the need for the second main branch section 42 and the third main branch section 43; in the bypass branch 5, the first bypass branch section 51 can be directly connected to the common section 6 downstream, thus eliminating the need for the second bypass branch section 52.

[0047] In the cooling circuit 1 according to this disclosure, the cooling pump 2 and the heat exchanger 3 are also mounted on the housing 11 of the electric drive unit 10. Both the main branch 4 and the bypass branch 5 are at least partially integrated into the housing 11 of the electric drive unit 10, and optionally entirely integrated into the housing 11, thereby achieving a high degree of integration of the cooling circuit 1 onto the electric drive unit 10. This integrated design eliminates the need for additional connectors such as connecting pipes, reducing component costs, simplifying the assembly of the cooling circuit 1, and reducing the volume occupied by the cooling circuit 1.

[0048] The following will combine Figures 3 to 9 The integration of cooling circuit 1 into electric drive unit 10 is described in detail.

[0049] like Figure 6 and Figure 7 As shown, a dedicated cooling pump mounting cavity 12a is provided on the housing 12, and a portion of the cooling pump 2 is housed within the cooling pump mounting cavity 2a. The cooling pump 2 includes a first outlet 21 and a second outlet 22 disposed on this portion. A main branch 4 opens into the cooling pump mounting cavity 12a and communicates with the first outlet 21; a bypass branch 5 also opens into the cooling pump mounting cavity 12a and communicates with the second outlet 22. The cooling pump 2 can operatively switch between pumping coolant from the first outlet 21 or the second outlet 22 based on whether the ambient temperature is above a threshold temperature. Exemplarily, this switching can be achieved by changing the rotation direction of the motor driving the cooling pump 2. Optionally, a fluid control device such as a three-way valve can be integrated into the cooling pump 2 to achieve the switching between the first outlet 21 and the second outlet 22.

[0050] Figure 3 A portion of main branch 4 is shown in a cross-sectional view, with arrows indicating the direction of coolant flow. (Reference) Figure 3 and combined Figure 5The first main branch section 41 of the main branch 4 is disposed on the housing 12, specifically formed by the first housing pipe 121 of the housing 12. The first housing pipe 121 is in fluid communication with the first outlet 21 of the cooling pump 2. The second main branch section 42 is disposed on the cover 13, specifically formed by the first cover pipe 131 of the cover 13. The first cover pipe 131 is connected to both the first housing pipe 121 and the heat exchanger 3, enabling fluid communication between the two. The first cover pipe 131 includes a first port 131a, which leads to the coolant flow channel in the heat exchanger 3. It is understood that the first housing pipe 121 can also be directly connected to the coolant flow channel in the heat exchanger 3.

[0051] Further reference Figure 9 The cover portion 13 also includes a second cover portion conduit 132 and a third cover portion conduit 133. The second cover portion conduit 132 includes a second port 132a through which the coolant flow path in the heat exchanger 3 opens, thereby enabling fluid communication between the second cover portion conduit 132 and the heat exchanger 3. The second cover portion conduit 132 and the third cover portion conduit 133 are in fluid communication, and the third cover portion conduit 133 connects to a fourth cover portion conduit 134, which forms part of the common section 6. The second cover portion conduit 132 and the third cover portion conduit 133 together form a third main branch section 43 connecting the heat exchanger 3 and the common section 6. That is, the third main branch section 43 is disposed on the cover portion 13. It is understood that the third main branch section 43 can also be formed by a single cover portion conduit, or the coolant flow path in the heat exchanger 3 can be directly connected to the fourth cover portion conduit 134.

[0052] Figure 4 The sectional view shows bypass branch 5 and common section 6, with arrows indicating the direction of coolant flow. (Reference) Figure 4 and combined Figure 5 , Figure 8 and Figure 9 The first bypass branch section 51 is disposed on the housing 12, specifically formed by the second housing pipe 122 of the housing 12. The second housing pipe 122 is in fluid communication with the second outlet 22 of the cooling pump 2. The second bypass branch section 52 is disposed on the cover 13, specifically formed by the sixth cover pipe 136 of the cover 13. The first cover pipe 136 is connected to both the second housing pipe 122 and the fourth cover pipe 134. That is, the sixth cover pipe 136 connects the second housing pipe 122 and the common section 6 in fluid communication. It can be understood that the second housing pipe 122 can be directly connected to the fourth cover pipe 134.

[0053] The cover portion 13 also includes a fifth cover portion conduit 135, which is in fluid communication with the fourth cover portion conduit 134, together forming a common section 6. The fifth cover portion conduit 135 is connected to the coolant inlet of the electric drive unit 10, i.e., coolant flows into the electric drive unit 10 from the fifth cover portion conduit 135. It is understood that the common section 6 can also be formed by a single cover portion conduit.

[0054] It should be understood that the above-described housing piping design in housing 12 and the above-described cover piping design in cover 13 are shown for illustrative purposes only. Where the main branch 4 and bypass branch 6 as described in this disclosure can be implemented, the piping arrangements in housing 12 and cover 13 can be appropriately adjusted without departing from the scope of this disclosure.

[0055] According to another aspect of this disclosure, a vehicle cooling system is proposed, which includes the cooling circuit 1 as described above. In addition to the cooling circuit 1, the vehicle cooling system may also include other cooling circuits, such as a water-cooling circuit.

[0056] According to another aspect of this disclosure, a vehicle is proposed that includes the cooling circuit 1 or vehicle cooling system as described above. The vehicle may be an electrified vehicle, such as a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a range-extended electric vehicle (REEV), or a fuel cell electric vehicle (FCEV). The vehicle may also be a hydrogen fuel cell vehicle. It should be understood that the aforementioned vehicle cooling system is not intended to cover all cooling devices included in a vehicle. The vehicle may include cooling devices not included in the aforementioned vehicle cooling system.

[0057] Certain features, structures, or characteristics in one or more embodiments of this disclosure may be appropriately combined.

[0058] The foregoing description is illustrative of the present disclosure and should not be construed as limiting it. While several exemplary embodiments of the present disclosure have been described, those skilled in the art will readily understand that many modifications may be made to the exemplary embodiments without departing from the novel teachings and advantages of the present disclosure. Therefore, all such modifications are intended to be included within the scope of the present disclosure as defined in the claims. It should be understood that the foregoing description is illustrative of the present disclosure and should not be construed as limiting it to the specific embodiments disclosed, and modifications to the disclosed embodiments and other embodiments are intended to be included within the scope of this disclosure.

Claims

1. A cooling circuit (1) for cooling an electric drive unit (10) of a vehicle, characterized in that, include: Cooling pump (2) is used to drive the coolant to circulate in the cooling circuit (1); A heat exchanger (3) is configured such that the coolant undergoes heat exchange as it flows through the heat exchanger (3); The main branch (4) is configured to guide coolant flowing from the cooling pump (2) through the heat exchanger (3) into the electric drive unit (10) when the ambient temperature is above a threshold temperature; and A bypass branch (5) is configured to guide coolant flowing from the cooling pump (2) into the electric drive unit (10) when the ambient temperature is below the threshold temperature.

2. The cooling circuit (1) according to claim 1, characterized in that, The electric drive unit (10) includes a housing (11), the cooling pump (2) and the heat exchanger (3) are mounted on the housing (11), and Wherein, at least a portion of the main branch (4) is integrated into the outer casing (11), and / or At least a portion of the bypass branch (5) is integrated into the housing (11).

3. The cooling circuit (1) according to claim 2, characterized in that, The outer casing (11) includes a housing (12) and a cover (13) assembled together, the cooling pump (2) is mounted on the housing (12), and the heat exchanger (3) is mounted on the cover (13).

4. The cooling circuit (1) according to claim 3, characterized in that, The housing (12) is provided with a cooling pump mounting cavity (12a), and the main branch (4) and the bypass branch (5) open toward the cooling pump mounting cavity (12a). A portion of the cooling pump (2) is housed within the cooling pump mounting cavity (12a), and the first outlet (21) of the cooling pump (2) is disposed on this portion and communicates with the main branch (4), and the second outlet (22) of the cooling pump (2) is disposed on this portion and communicates with the bypass branch (5).

5. The cooling circuit (1) according to claim 3 or 4, characterized in that, The main branch (4) and the bypass branch (5) include a common section (6) arranged on the cover (13) in the direction of coolant flow, the common section (6) being arranged downstream of the heat exchanger (3).

6. The cooling circuit (1) according to claim 5, characterized in that, The main branch (4) further includes a first main branch section (41) arranged on the housing (12), wherein, in the direction of coolant flow, the first main branch section (41) is arranged upstream of the heat exchanger (3).

7. The cooling circuit (1) according to claim 6, characterized in that, The main branch (4) further includes a second main branch section (42) and a third main branch section (43) arranged on the cover (13), wherein, in the coolant flow direction, the second main branch section (42) is arranged between the first main branch section (41) and the heat exchanger (3), and the third main branch section (43) is arranged between the heat exchanger (3) and the common section (6).

8. The cooling circuit (1) according to claim 5, characterized in that, The bypass branch (5) further includes a first bypass branch section (51) arranged on the housing (12), wherein, in the coolant flow direction, the first bypass branch section (51) is arranged upstream of the common section (6).

9. The cooling circuit (1) according to claim 8, characterized in that, The bypass branch (5) further includes a second bypass branch section (52) arranged on the cover (13), wherein, in the coolant flow direction, the second bypass branch section (52) is arranged between the first bypass branch section (51) and the common section (6).

10. The cooling circuit (1) according to claim 7, characterized in that, The housing (12) includes a first housing conduit (121) forming at least a portion of the first main branch section (41), the first housing conduit (121) being in fluid communication with the first outlet (21) of the cooling pump (2), and The cover (13) includes a first cover pipe (131), a second cover pipe (132) and a third cover pipe (133). The first cover pipe (131) forms at least a portion of the second main branch section (42) and fluidly communicates with the first shell pipe (121) and the heat exchanger (3). The second cover pipe (132) and the third cover pipe (133) are fluidly communicated with each other to form at least a portion of the third main branch section (43). The second cover pipe (132) is fluidly communicated with the heat exchanger (3), and the third cover pipe (133) is fluidly communicated with the common section (6).

11. The cooling circuit (1) according to claim 10, characterized in that, The cover (13) also includes a fourth cover pipe (134) and a fifth cover pipe (135) that are in fluid communication with each other forming the common section (6), the fifth cover pipe (135) being connected to the coolant inlet of the electric drive device (10). The third cover pipe (133) and the fourth cover pipe (134) are in fluid communication.

12. The cooling circuit (1) according to claim 9, characterized in that, The housing (12) includes a second housing conduit (122) forming the first bypass branch section (51), the second housing conduit (122) being in fluid communication with the second outlet (22) of the cooling pump (2), and The cover (13) includes a sixth cover conduit (136) forming the second bypass branch section (52), the sixth cover conduit (136) fluidly communicating the second housing conduit (122) and the common section (6).

13. The cooling circuit (1) according to claim 12, characterized in that, The cover (13) also includes a fourth cover pipe (134) and a fifth cover pipe (135) that are in fluid communication with each other forming the common section (6), the fifth cover pipe (135) being connected to the coolant inlet of the electric drive device (10). The sixth cover pipe (136) is in fluid communication with the fourth cover pipe (134).

14. The cooling circuit (1) according to any one of claims 1 to 4, characterized in that, The threshold temperature is between -25°C and -35°C.

15. The cooling circuit (1) according to claim 14, characterized in that, The threshold temperature is -30℃.

16. A vehicle cooling system, characterized in that, The vehicle cooling system includes a cooling circuit (1) as described in any one of claims 1 to 15.

17. A vehicle, characterized in that, The vehicle includes a cooling circuit (1) according to any one of claims 1 to 15 or a vehicle cooling system according to claim 16.

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