Thermal management system for electric excavators and electric excavators

Abstract

This invention discloses a thermal management system for an electric excavator and an electric excavator, relating to the field of excavators, for effective heat management of the electric excavator. The system includes a heat exchange path, a motor cooling path, and a refrigerant circulation loop. The heat exchange path includes a battery pack. The motor cooling path includes a first branch, a second branch, and a third branch; the second and third branches are arranged in parallel. The refrigerant circulation loop includes a compressor, a condenser, a first evaporator, a second evaporator, and a shut-off valve; the refrigerant circulation loop is configured such that, through the shut-off valve, the compressor, condenser, and first evaporator form a first refrigerant loop; or, the compressor, condenser, and second evaporator form a second refrigerant loop. The motor cooling path and the refrigerant circulation loop can selectively adjust the temperature of the battery pack; the refrigerant circulation loop can selectively adjust the temperature of the motor cooling path. The above solution enables temperature management and control of the battery and motor.

Description

Technical Field

[0001] This invention relates to the field of excavators, and more specifically to a thermal management system for an electric excavator and an electric excavator. Background Technology

[0002] Excavators are widely used, and their current power systems are mainly internal combustion engines, with the working devices driven by hydraulic systems. With increasingly stringent environmental policies, emission requirements for non-road machinery are becoming more stringent. Simultaneously, with the development of new energy technologies, excavators are beginning to incorporate battery replacement designs in their power systems.

[0003] The inventors discovered that existing technologies suffer from at least the following problems: As the power source for the excavator, the power battery must meet the demands of frequent high-power discharge, continuous discharge, and high-power charging. In high-temperature environments or under high-current charging conditions, the battery's chemical reactions are intense, resulting in severe internal heat generation. Furthermore, the large size of the battery pack and the large number of cells make internal heat dissipation difficult, which not only affects battery power but may even cause thermal imbalance, leading to safety accidents. In low-temperature environments, the battery's internal resistance increases, resulting in battery performance degradation. Summary of the Invention

[0004] This invention proposes a thermal management system for an electric excavator and an electric excavator, which enables effective management of the heat of the electric excavator.

[0005] This invention provides a thermal management system for an electric drive excavator, comprising:

[0006] The heat flow path to be replaced includes the battery pack;

[0007] The motor cooling flow path includes a first branch, a second branch, and a third branch; the second branch and the third branch are arranged in parallel; the first branch can selectively form a liquid flow loop with one of the second branch and the third branch; and

[0008] A refrigerant circulation loop includes a compressor, a condenser, a first evaporator, a second evaporator, and a shut-off valve; the refrigerant circulation loop is configured to achieve, via the shut-off valve, that the compressor, the condenser, and the first evaporator form a first refrigerant loop; or, that the compressor, the condenser, and the second evaporator form a second refrigerant loop;

[0009] The temperature of the battery pack can be selectively adjusted by either the motor cooling flow path or the refrigerant circulation loop; the temperature of the motor cooling flow path can be selectively adjusted by the refrigerant circulation loop.

[0010] In some embodiments, the battery pack to be heat exchanged includes a first cooling water channel; the first cooling water channel includes a first inlet and a first outlet;

[0011] The heat exchange path also includes:

[0012] A first water pump includes a second inlet and a second outlet; the second inlet of the first water pump is connected to the first outlet of the first cooling water channel; and

[0013] The heater includes a third inlet and a third outlet; the third inlet of the heater is connected to the second outlet of the first water pump.

[0014] The first evaporator includes a first heat exchange channel and a second heat exchange channel. The first heat exchange channel is connected to the third outlet of the heater and the first inlet of the first cooling water channel of the battery pack. The second heat exchange channel is connected to the condenser and the compressor. The first evaporator realizes heat exchange between the refrigerant flow path and the heat exchange path to be cooled, thereby cooling the battery pack in the heat exchange path.

[0015] In some embodiments, the heat exchange path further includes:

[0016] A plate heat exchanger includes a third heat exchange channel and a fourth heat exchange channel. The third heat exchange channel is located between the first heat exchange channel of the first evaporator and the first water inlet of the battery pack. The fourth heat exchange channel is configured to switch between the following states: disconnected from the motor cooling path and connected in series with the motor cooling path.

[0017] The plate heat exchanger is used to exchange heat between the heat exchange path and the motor cooling path, thereby heating the battery pack in the heat exchange path.

[0018] In some embodiments, the thermal management system for an electric excavator further includes:

[0019] The first switching valve includes a first port, a second port, a third port, and a fourth port; the first port and the third port are located in the first branch; the second port is connected to the first end of the fourth heat exchange channel of the plate heat exchanger, and the fourth port is connected to the second end of the fourth heat exchange channel of the plate heat exchanger.

[0020] The first switching valve includes a first valve position and a second valve position;

[0021] When the first switching valve is in the first valve position, the first port and the second port are connected, and the third port and the fourth port are connected;

[0022] When the first switching valve is in the second valve position, the first port and the third port are connected, and the second port and the fourth port are connected.

[0023] In some embodiments, the motor cooling flow path further includes:

[0024] The second switching valve includes a fifth port, a sixth port, and a seventh port; the fifth port is connected to the first branch, the sixth port is connected to the second branch, and the seventh port is connected to the third branch.

[0025] The second switching valve includes a third valve position and a fourth valve position;

[0026] When the second switching valve is in the third valve position, the sixth port and the seventh port are connected;

[0027] When the second switching valve is in the fourth valve position, the fifth port and the seventh port are connected.

[0028] In some embodiments, as described above in the thermal management system for an electric excavator, the second branch includes a radiator, the sixth port of the second switching valve is connected to the inlet of the radiator, and the outlet of the radiator is connected to the first branch of the motor cooling flow path.

[0029] In some embodiments, the thermal management system for an electric excavator further includes:

[0030] The third switching valve includes a first connection port, a second connection port, a third connection port, and a fourth connection port; the first connection port is connected to the end of the third heat exchange channel of the plate heat exchanger away from the first evaporator; the second connection port is connected to the first water inlet of the battery pack; the third connection port is connected to the seventh port of the second switching valve; and the fourth connection port is connected to the outlet of the radiator.

[0031] In some embodiments, the second evaporator includes:

[0032] The fifth heat exchange channel is located between the condenser and the compressor; and

[0033] The sixth heat exchange channel is connected to the heater and the first inlet of the first cooling water channel. The sixth heat exchange channel is configured to switch between the following states: disconnected from the first branch of the motor cooling channel and connected in series with the first branch.

[0034] In some embodiments, the thermal management system for an electric excavator further includes:

[0035] The fourth switching valve includes a first connecting port, a second connecting port, a third connecting port, and a fourth connecting port; the second connecting port and the fourth connecting port are located in the first branch and downstream of the radiator; the first connecting port is connected to the first end of the fourth heat exchange channel of the plate heat exchanger, and the third connecting port is connected to the second end of the fourth heat exchange channel;

[0036] The fourth switching valve includes a fifth valve position and a sixth valve position;

[0037] When the fourth switching valve is in the fifth valve position, the first connection port and the second connection port are connected, and the third connection port and the fourth connection port are connected;

[0038] When the fourth switching valve is in the sixth valve position, the first connection port and the third connection port are connected, and the second connection port and the fourth connection port are connected.

[0039] In some embodiments, the thermal management system of the electric drive excavator includes a first operating mode;

[0040] The first working mode: the refrigerant circulation loop exchanges heat with the heat exchange flow path to cool the battery pack.

[0041] In some embodiments, when the battery pack is in a high-power discharge mode or the ambient temperature is higher than a first set temperature, the thermal management system of the electric drive excavator is in a first operating mode.

[0042] In some embodiments, the thermal management system of the electric drive excavator includes a second operating mode;

[0043] The second operating mode: the second branch of the motor cooling flow path is connected in series with the heat exchange flow path to form a loop, so as to cool the battery pack.

[0044] In some embodiments, when the battery pack is charging and the ambient temperature is lower than a second set temperature, the thermal management system of the electric excavator is in a second operating mode.

[0045] In some embodiments, the thermal management system of the electric drive excavator includes a third operating mode;

[0046] The third operating mode: the first branch and the third branch of the motor cooling flow path are connected in series to form a loop, and the plate heat exchanger is located in the loop to use the heat of the motor cooling flow path to heat the battery pack.

[0047] In some embodiments, when the ambient temperature is lower than a second set temperature and the battery pack is activated, the thermal management system of the electric excavator is in a third operating mode.

[0048] In some embodiments, the thermal management system of the electric drive excavator includes a fourth operating mode;

[0049] The fourth working mode: the first branch and the second branch of the motor cooling flow path are connected in series and form a loop, so as to use the heat sink of the second branch to cool the motor of the first branch.

[0050] In some embodiments, when the ambient temperature is lower than a third set temperature and the motor on the first branch is in operation, the thermal management system of the electric excavator is in a fourth operating mode.

[0051] In some embodiments, the thermal management system of the electric drive excavator includes a fifth operating mode;

[0052] The fifth working mode: the first branch and the second branch of the motor cooling flow path are connected in series, and the first branch exchanges heat with the refrigerant circulation loop, so as to use the radiator of the second branch and the refrigerant circulation loop to cool the motor of the first branch.

[0053] In some embodiments, when the ambient temperature exceeds a third set temperature and the ambient temperature is lower than the outlet water temperature of the first branch, the motor on the first branch is in operation, and the electric drive excavator thermal management system is in a fifth operating mode.

[0054] In some embodiments, the thermal management system of the electric drive excavator includes a sixth operating mode;

[0055] The sixth working mode: the first branch and the third branch of the motor cooling flow path are connected in series, and the first branch exchanges heat with the refrigerant circulation loop, so as to use the heat exchange effect of the radiator of the second branch of the motor cooling flow path and the refrigerant circulation loop to cool down the motor of the first branch.

[0056] In some embodiments, when the ambient temperature is not lower than the outlet water temperature of the first branch of the motor cooling flow path, the motor on the first branch is in operation, and the electric drive excavator thermal management system is in the sixth operating mode.

[0057] In some embodiments, the first branch of the motor cooling flow path includes:

[0058] Second water pump;

[0059] A diversion valve is located downstream of and connected to the second water pump. The diversion valve includes a first working port, a second working port, and a third working port arranged in parallel. The diversion valve is configured to divert the fluid output from the second water pump.

[0060] The cooling flow path of the boom electric drive system is connected to the first working port and is located downstream of the first working port;

[0061] The cooling flow path of the turntable electric drive system is connected to the second working port and is located downstream of the second working port;

[0062] The cooling flow path of the electric drive system is connected to the third working port and located downstream of the third working port; and

[0063] The confluence valve is located downstream of the cooling flow paths of the boom electric drive system, the turntable electric drive system, and the travel electric drive system, and is connected to all of these cooling flow paths to achieve confluence.

[0064] This invention also provides an electric drive excavator, including the electric drive excavator thermal management system provided by any of the technical solutions of this invention.

[0065] In the above technical solution, the refrigerant circulation loop can be used to cool both the heat exchange path and the motor cooling path, thereby achieving temperature reduction for the battery pack in the heat exchange path and the motor in the motor cooling path. This technical solution enables temperature management and control of the battery and motor, ensuring that core components such as the battery and motor are always at their optimal operating temperature, thus achieving high-efficiency output. Attached Figure Description

[0066] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0067] Figure 1 This is a schematic diagram of the thermal management system of an electric drive excavator provided in an embodiment of the present invention.

[0068] Figure 2 A schematic diagram illustrating the principle of the thermal management system of an electric drive excavator in its first working mode, as provided in an embodiment of the present invention.

[0069] Figure 3 This is a schematic diagram illustrating the principle of the thermal management system of an electric drive excavator in its second operating mode, as provided in an embodiment of the present invention.

[0070] Figure 4 A schematic diagram illustrating the principle of the thermal management system of an electric drive excavator in its third operating mode, as provided in an embodiment of the present invention.

[0071] Figure 5 This is a schematic diagram illustrating the principle of the thermal management system of an electric drive excavator in its fourth operating mode, as provided in an embodiment of the present invention.

[0072] Figure 6 A schematic diagram illustrating the principle of the thermal management system of an electric drive excavator in its fifth operating mode, as provided in an embodiment of the present invention.

[0073] Figure 7A schematic diagram illustrating the principle of the thermal management system of an electric drive excavator in its sixth operating mode, as provided in an embodiment of the present invention.

[0074] Figure label:

[0075] S1, heat exchange path; S2, motor cooling path; S3, refrigerant circulation loop; S21, first branch; S22, second branch; S23, third branch;

[0076] 1. Compressor; 2. Condenser; 3. Shut-off valve; 41. First electronic expansion valve; 42. Second electronic expansion valve; 51. First evaporator; 52. Second evaporator; 6. Expansion tank; 7. Heater; 81. First water pump; 9. Battery pack; 10. Plate heat exchanger; 111. First switching valve; 112. Third switching valve; 113. Fourth switching valve; 121. First check valve; 122. Second check valve; 13. Second switching valve; 14. Radiator; 151. 152. Diverter valve; 161. Merging valve; 162. First pressure and temperature sensing element; 163. Second pressure and temperature sensing element; 164. Third pressure and temperature sensing element; 165. Fourth pressure and temperature sensing element; 166. Fifth pressure and temperature sensing element; 171. First flow switch valve; 172. Second flow switch valve; 173. Third flow switch valve; 18. Cooling flow path for boom electric drive system; 19. Cooling flow path for turntable electric drive system; 20. Cooling flow path for travel electric drive system. Detailed Implementation

[0077] The following is combined Figures 1 to 7 The technical solutions provided by this invention will be described in more detail below. The descriptions of exemplary embodiments are merely illustrative and are in no way intended to limit this disclosure or its application or use. This disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make this disclosure thorough and complete, and to fully express the scope of this disclosure to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0078] The terms “first,” “second,” and similar words used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as “including” or “contains” mean that the element preceding the word covers the element listed after the word, and do not exclude the possibility of covering other elements as well.

[0079] In this disclosure, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may be not directly connected to the other devices but have an intermediary device.

[0080] All terms used in this disclosure, including technical or scientific terms, have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as a dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0081] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment shall be considered part of the specification.

[0082] The dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Common structural elements or elements of the same kind are given the same reference numerals in the various drawings, and repeated descriptions of them are omitted where appropriate.

[0083] See Figure 1 This invention provides a thermal management system for an electric excavator, including a heat exchange path S1, a motor cooling path S2, and a refrigerant circulation loop S3. The heat exchange path S1 includes a battery pack 9. The motor cooling path S2 includes a first branch S21, a second branch S22, and a third branch S23; the second branch S22 and the third branch S23 are arranged in parallel; the first branch S21 can optionally form a liquid flow loop with one of the second branch S22 or the third branch S23. The refrigerant circulation loop S3 includes a compressor 1, a condenser 2, a first evaporator 51, and a second evaporator 52. The refrigerant circulation loop S3 is configured such that: the compressor 1, the condenser 2, and the first evaporator 51 form a first refrigerant loop; or, the compressor 1, the condenser 2, and the second evaporator 52 form a second refrigerant loop. The motor cooling path S2 and the refrigerant circulation loop S3 can selectively adjust the temperature of the battery pack 9; the refrigerant circulation loop S3 can selectively adjust the temperature of the motor cooling path S2.

[0084] In the above technical solution, the refrigerant circulation loop S3 can be used to cool both the heat exchange flow path S1 and the motor cooling flow path S2, thereby achieving the cooling of the battery pack 9 in the heat exchange flow path S1 and the motor in the motor cooling flow path S2.

[0085] The motor cooling flow path S2 is a flow path for cooling the working motor. When the motor cooling flow path S2 forms a loop, the fluid temperature within it is relatively high. In low-temperature environments, the battery pack 9 in the heat exchange flow path S1 may fail to start smoothly due to the low ambient temperature. In this case, the heat within the motor cooling flow path S2 can be used to heat the battery pack 9, allowing it to start smoothly. Furthermore, the motor cooling flow path S2 includes three branches: the first branch S21, the second branch S22, and the third branch S23. The first branch S21 and the second branch S22 can form a loop to achieve the closure of the motor cooling flow path S2 and the circulation of the fluid (mainly water); the first branch S21 and the third branch S23 can also form a loop to achieve the closure of the motor cooling flow path S2 and the circulation of the fluid. The fluid flow path lengths of the second branch S22 and the third branch S23 are different to achieve different cooling effects. The cooling pipes are shorter, the flow resistance is lower, and the water pump load is smaller. Specifically, the fluid flow path of the second branch S22 is longer than that of the third branch S23. The second branch S22 can also be connected in series with the heat exchange flow path S1 to form a loop, thereby extending the flow path of the water used to cool the battery pack 9 and improving the cooling effect on the battery pack 9.

[0086] See Figure 1 The battery pack 9 in the heat exchange flow path S1 includes a first cooling water flow channel. The first cooling water flow channel includes a first inlet and a first outlet. The heat exchange flow path S1 also includes a first water pump 81 and a heater 7. The first water pump 81 includes a second inlet and a second outlet; the second inlet of the first water pump 81 is connected to the first outlet of the first cooling water flow channel. The heater 7 includes a third inlet and a third outlet; the third inlet of the heater 7 is connected to the second outlet of the first water pump 81. The first evaporator 51 includes a first heat exchange flow channel and a second heat exchange flow channel. The first heat exchange flow channel is connected to the third outlet of the heater 7 and the first inlet of the first cooling water flow channel of the battery pack 9. The second heat exchange flow channel is connected to the condenser 2 and the compressor 1. Heat exchange between the refrigerant flow path and the heat exchange flow path S1 is achieved through the first evaporator 51 to cool the battery pack 9 in the heat exchange flow path S1.

[0087] The battery pack 9 integrates a first cooling water channel arranged in a serpentine or parallel pattern. The first cooling water channel is made of corrosion-resistant aluminum alloy or copper alloy. The first cooling water channel has two ports: a first inlet and a first outlet. Both the first inlet and the first outlet are equipped with standard quick-connect interfaces for easy connection with other components; the inner wall of the first cooling water channel is smoothed to reduce fluid flow resistance.

[0088] The first water pump 81 can adopt a centrifugal or gear-type pump body, and the outer shell of the first water pump 81 is made of engineering plastic or cast aluminum. The first water pump 81 includes a second inlet and a second outlet, and the inner diameter of the second inlet interface matches the first outlet of the first cooling water flow channel. The first water pump 81 can have a built-in variable frequency motor, and the speed can be adjusted by a controller, allowing the first water pump 81 to output a wider range of flow rates.

[0089] Heater 7 can be a PTC heater. The PTC heater includes a PTC heating element, an aluminum heat sink, and an insulating shell. A channel is formed inside the heat sink, with a third inlet and a third outlet at both ends. The operating state of the PTC heating element is adjustable; the heat sink is always conductive regardless of whether the PTC heating element is active. When the PTC heating element is active, it heats the water inside the heat sink. When the PTC heating element is not active, it does not heat the water inside the heat sink.

[0090] The first evaporator 51 adopts a dual-channel independent structure. The first heat exchange channel on the side of the heat exchange path S1 can be multiple sets of parallel aluminum flat tubes. The two ends of the first heat exchange channel are connected to the water outlet of the heater 7 and the first water inlet of the battery pack 9 through a manifold. The second heat exchange channel on the side of the refrigerant circulation loop S3 is a copper tube staggered with the first heat exchange channel, which carries refrigerant and is connected to the condenser 2 and the compressor 1 at both ends. The first heat exchange channel and the second heat exchange channel are adjacent to or connected to each other to achieve heat conduction.

[0091] In some embodiments, the heat exchange flow path S1 further includes an expansion tank 6. When the water in the first heat exchange flow path boils and generates water vapor, the water vapor can enter the expansion tank 6 and be exhausted through the expansion tank 6.

[0092] In some embodiments, the heat exchange flow path S1 further includes a first pressure and temperature detection element 161, which is installed at the first water inlet of the battery pack 9 to detect the pressure and temperature of the water entering the battery pack 9.

[0093] The first water pump 81 rotates, creating a negative pressure in the pump body, which draws the fluid in from the first inlet of the first water pump 81, and then discharges it from the first outlet after pressurization. The first water pump 81 provides continuous power for the fluid circulation of the entire flow path, ensuring the continuity of water flow in the heat exchange flow path S1.

[0094] In some embodiments, the heat exchange path S1 further includes a plate heat exchanger 10. The plate heat exchanger 10 includes a third heat exchange channel and a fourth heat exchange channel. The third heat exchange channel is located between the first heat exchange channel of the first evaporator 51 and the first water inlet of the battery pack 9. The fourth heat exchange channel is configured to switch between being disconnected from the motor cooling path S2 and being connected in series with the motor cooling path S2. Heat exchange between the heat exchange path S1 and the motor cooling path S2 is achieved through the plate heat exchanger 10 to heat the battery pack 9 in the heat exchange path S1.

[0095] The plate heat exchanger 10 can specifically be a water-to-water heat exchanger. The plate heat exchanger 10 adopts a detachable plate stacking structure, with the plates made of 304 stainless steel or titanium alloy, which is corrosion-resistant and has a high thermal conductivity. Herringbone or corrugated flow channels are pressed onto the surface of each plate to enhance fluid turbulence and improve heat exchange efficiency. The plate heat exchanger 10 internally forms two independent and staggered flow channels: a third heat exchange channel and a fourth heat exchange channel.

[0096] The plate heat exchanger 10 enables heat exchange between the motor cooling flow path S2 and the heat exchange flow path S1, thereby recovering and utilizing the heat in the motor cooling flow path S2 to heat the battery pack 9 in the heat exchange flow path S1, reducing the energy consumption of the heater 7, and enabling the battery pack 9 to be heated even when the heater 7 is not working.

[0097] The third heat exchange channel is located on the side of the heat exchange path S1. The two ends of the third heat exchange channel are respectively provided with an inlet and an outlet. The inlet of the third heat exchange channel is connected to the first heat exchange channel of the first evaporator 51, and the outlet of the third heat exchange channel is connected to the inlet of the first cooling water channel of the battery pack 9. The flow area of ​​the third heat exchange channel matches the flow area of ​​the heat exchange path S1.

[0098] The fourth heat exchange channel is located on the side of the motor cooling flow path S2. Both ends of the fourth heat exchange channel also have independent interfaces for connection to the first switching valve 111. The first switching valve 111 enables switching between disconnected and connected states with the motor cooling flow path S2.

[0099] The specific structure of the first switching valve 111 will be introduced later. Here, we will first introduce the control of the position of the plate heat exchanger 10 by the first switching valve 111. The first switching valve 111 controls the position of the valve core through an electromagnetic signal to achieve precise switching between series and disconnection: when the battery pack 9 does not need heating or the motor has no residual heat, it switches to disconnect the plate heat exchanger 10 from the motor cooling flow path S2 to avoid mutual interference between the motor cooling flow path S2 and the heat exchange flow path S1. When the waste heat recovery conditions are met, it switches to the state where the plate heat exchanger 10 and the motor cooling flow path S2 are connected in series to ensure that the high-temperature fluid accurately enters the plate heat exchanger 10 and ensures that the heat exchange process is stable and controllable.

[0100] The first cooling water channel of the battery pack 9 is used to connect to the outlet end of the third heat exchange channel of the plate heat exchanger 10, so that fluid flows from the plate heat exchanger 10 into the battery pack 9. The first heat exchange channel of the first evaporator 51 is connected to the inlet end of the third heat exchange channel of the plate heat exchanger 10.

[0101] The plate heat exchanger 10 realizes indirect heat exchange between two fluids: when the high-temperature fluid waste heat carrier of the motor cooling flow path S2 flows in the fourth flow channel, the heat is transferred to the fluid to be exchanged in the third cooling flow channel through the metal plate with high thermal conductivity, so as to realize the use of motor waste heat to heat the battery pack 9.

[0102] The above technical solution replaces the active heating of heater 7 with waste heat recovery. If the heat generated during motor operation is not recovered, it will be discharged to the outside through the radiator 14 of the motor cooling flow path S2, resulting in energy waste. The plate heat exchanger 10 can transfer this waste heat to the heat exchange flow path S1 to heat the battery pack 9, eliminating the need to start heater 7 and consume electrical energy, thus achieving energy reuse and energy saving.

[0103] See also Figure 1 The first switching valve 111 is specifically a four-way valve. The first switching valve 111 includes a first port, a second port, a third port, and a fourth port. The first port and the third port are located in the first branch S21; the second port is connected to the first end of the fourth heat exchange channel of the plate heat exchanger 10, and the fourth port is connected to the second end of the fourth heat exchange channel of the plate heat exchanger 10. The first switching valve 111 includes a first valve position and a second valve position.

[0104] When the first switching valve 111 is in the first valve position, the first port and the second port are connected, and the third port and the fourth port are also connected. At this time, the plate heat exchanger 10 is connected in series to the motor cooling flow path S2.

[0105] When the first switching valve 111 is in the second valve position, the first port and the third port are connected, and the second port and the fourth port are connected. At this time, the plate heat exchanger 10 is disconnected from the motor cooling flow path S2.

[0106] See also Figure 1The first branch S21 of the motor cooling flow path S2 includes a second water pump 82, a diversion valve 151, a boom electric drive system cooling flow path 18, a turntable electric drive system cooling flow path 19, a travel electric drive system cooling flow path 20, and a confluence valve 152. The diversion valve 151 is located downstream of and connected to the second water pump 82. The diversion valve 151 includes a first working port, a second working port, and a third working port arranged in parallel. The diversion valve 151 is configured to divert the fluid output from the second water pump 82. The boom electric drive system cooling flow path 18 is connected to and located downstream of the first working port. The turntable electric drive system cooling flow path 19 is connected to and located downstream of the second working port. The travel electric drive system cooling flow path 20 is connected to and located downstream of the third working port. The confluence valve 152 is located downstream of the boom electric drive system cooling flow path 18, the turntable electric drive system cooling flow path 19, and the travel electric drive system cooling flow path 20, and is connected to all three systems to achieve confluence.

[0107] The first branch S21 of the motor cooling flow path S2 serves as a branch of the motor cooling system, responsible for cooling the three major electric drive systems: boom, turntable, and travel.

[0108] The second water pump 82 can adopt a centrifugal pump body structure, and the pump body is made of cast aluminum to achieve lightweight and temperature resistance. The second water pump 82 is configured to meet the medium-to-high flow rate requirements of the motor cooling flow path S2. The inlet end of the second water pump 82 is equipped with a filter interface to prevent impurities from entering the flow path. The outlet end of the second water pump 82 is connected to the inlet of the diverter valve 151 through a flange or quick-connect fitting. The drive end of the second water pump 82 is equipped with a permanent magnet synchronous motor, and the speed can be adjusted by the controller according to the temperature of the electric drive system to achieve dynamic control of the flow rate of the second water pump 82.

[0109] The diversion valve 151 can adopt a multi-channel fixed-diversion valve structure. The valve body of the diversion valve 151 is made of brass, which is corrosion-resistant and has low flow loss. The inlet of the diversion valve 151 is connected to the outlet of the second water pump 82. The diversion valve 151 has three parallel diversion chambers, corresponding to the first working port, the second working port, and the third working port, respectively. Each working port is equipped with an adjustable flow valve core at the front end, which can preset the diversion ratio according to the heat generation power of the three electric drive systems, such as boom:turntable:travel equals 4:3:3, to ensure that each subsystem receives a matching cooling flow. Pressure and temperature sensors can be installed at each working port of the diversion valve 151 to monitor the inlet water pressure and temperature in real time. The structures of the boom electric drive system cooling flow path 18, the turntable electric drive system cooling flow path 19, and the travel electric drive system cooling flow path 20 can be implemented in various ways to meet the cooling requirements.

[0110] The boom electric drive system cooling flow path 18 includes multiple sets of parallel aluminum cooling pipes. These cooling pipes are wound around or attached to the core heat-generating components of the boom electric drive motor and reducer housing. Both ends of the cooling pipes are connected to the first working port of the diverter valve 151 and the first corresponding interface of the merging valve 152, respectively. The inner diameter of the cooling pipe matches the working port of the diverter valve 151, and heat dissipation fins can be provided on the outer wall of the pipe to increase the heat exchange area.

[0111] The structure of the turntable electric drive system cooling flow path 19 is similar to that of the boom electric drive system cooling flow path 18. The cooling pipes of the turntable electric drive system cooling flow path 19 are attached to the surface of the turntable electric drive motor and the rotary reducer. Due to the compact layout of the turntable components, the cooling pipes are arranged in a serpentine pattern to adapt to the space. The two ends are respectively connected to the second working port of the diversion valve 151 and the second corresponding interface of the confluence valve 152.

[0112] The cooling pipes of the walking electric drive system cooling flow path 20 are divided into two groups, corresponding to the front and rear walking electric drive motors respectively. The two groups of cooling pipes are first connected in parallel and then connected to the third working port of the diverter valve 151 and the third corresponding interface of the merging valve 152, so that the cooling flow of the front and rear walking motors is balanced.

[0113] The confluence valve 152 adopts a multi-inlet, one-outlet manifold structure. The valve body is made of brass and has three inlet ports (first, second, and third corresponding interfaces) that correspond to the cooling flow paths of the three main subsystems, respectively. It also has one outlet port connected to the subsequent circuit of the motor cooling flow path S2, such as the radiator 14 or the plate heat exchanger 10. The confluence valve 152 has an internal manifold chamber. A check valve at the inlet of the chamber prevents backflow of fluid into the subsystems, and a flow stabilizing valve core at the outlet buffers pressure fluctuations during the confluence of fluids from the various subsystems, ensuring stable fluid flow after confluence.

[0114] See also Figure 1 In some embodiments, the motor cooling flow path S2 further includes a second switching valve 13. The second switching valve 13 includes a fifth port, a sixth port, and a seventh port. The fifth port is connected to the first branch S21, the sixth port is connected to the second branch S22, and the seventh port is connected to the third branch S23. The second switching valve 13 includes a third valve position and a fourth valve position.

[0115] When the second switching valve 13 is in the third valve position, the sixth port and the seventh port are connected. At this time, the first branch S21 and the second branch S22 are connected in series and form a loop.

[0116] When the second switching valve 13 is in the fourth valve position, the fifth port and the seventh port are connected. At this time, the first branch S21 and the third branch S23 are connected in series and form a loop.

[0117] By forming different loops, the length of the flow path of the motor cooling flow path S2 can be changed to achieve different heat exchange effects.

[0118] In some embodiments, the second branch S22 includes a radiator 14, the sixth port of the second switching valve 13 is connected to the inlet of the radiator 14, and the outlet of the radiator 14 is connected to the first branch S21 of the motor cooling flow path S2.

[0119] The heat sink 14 can adopt a tube-and-strip air-cooled heat sink structure, with the overall frame made of aluminum alloy, which is lightweight and has excellent thermal conductivity. The heat sink 14 includes multiple parallel aluminum heat pipes and corrugated aluminum heat dissipation strips. The heat dissipation strips tightly wrap around the outer wall of the heat pipes, forming a dense heat dissipation surface. An axial cooling fan is installed on the side of the heat sink 14. The fan is controlled by a temperature sensor to enhance the forced cooling effect.

[0120] See Figure 1 The medium in both the motor cooling flow path S2 and the heat exchange flow path S1 can be water. In some embodiments, the thermal management system of the electric drive excavator further includes a third switching valve 112, which includes a first connection port, a second connection port, a third connection port, and a fourth connection port. The first connection port is connected to the end of the third heat exchange flow channel of the plate heat exchanger 10 away from the first heat exchanger. The second connection port is connected to the first water inlet of the battery pack 9. The third connection port is connected to the seventh port of the second switching valve 13; the fourth connection port is connected to the outlet of the radiator 14.

[0121] By using the third switching valve 112, the second branch S22 of the motor cooling flow path S2 can be connected in series with the heat exchange flow path S1 to form a new loop, so as to utilize the radiator 14 to dissipate heat from the battery pack 9 and improve the heat dissipation effect on the battery pack 9. This eliminates the need for a separate radiator 14, making the thermal management system of the electric drive excavator more compact.

[0122] In some embodiments, the second evaporator 52 includes a fifth heat exchange channel and a sixth heat exchange channel. The fifth heat exchange channel is located between the condenser 2 and the compressor 1. The sixth heat exchange channel is connected to the heater 7 and the first inlet of the first cooling water channel, and the sixth heat exchange channel is configured to switch between the following states: disconnected from the first branch S21 of the motor cooling flow path S2, and connected in series with the first branch S21.

[0123] The second evaporator 52 and the first evaporator 51 can be used interchangeably. When the first evaporator 51 is used, the refrigerant circulation loop S3 can cool the heat exchange path S1. The fluid in the refrigerant circulation loop S3 is refrigerant, which has a good heat exchange effect. When the second evaporator 52 is used, the refrigerant circulation loop S3 can cool the motor cooling path S2.

[0124] In some embodiments, the thermal management system of the electric excavator further includes a fourth switching valve 113, which may be a four-way valve. The fourth switching valve 113 includes a first connecting port, a second connecting port, a third connecting port, and a fourth connecting port. The second connecting port and the fourth connecting port are located in the first branch S21 and downstream of the radiator 14; the first connecting port is connected to the first end of the fourth heat exchange channel, and the third connecting port is connected to the second end of the fourth heat exchange channel.

[0125] The fourth switching valve 113 includes a fifth valve position and a sixth valve position.

[0126] When the fourth switching valve 113 is in the fifth position, the first and second connecting ports are connected, and the third and fourth connecting ports are also connected. At this time, the second evaporator 52 is connected in series to the motor cooling flow path S2.

[0127] When the fourth switching valve 113 is in the sixth valve position, the first and third connecting ports are connected, and the second and fourth connecting ports are also connected. At this time, the second evaporator 52 is disconnected from the motor cooling flow path S2.

[0128] The following section details the working modes of the thermal management system for electric drive excavators.

[0129] See Figure 2 The thermal management system of the electric drive excavator includes a first operating mode, namely the high-temperature heat dissipation mode for battery pack 9. In the first operating mode: the refrigerant circulation loop S3 exchanges heat with the heat exchange path S1 to cool the battery pack 9. Specifically, the electric drive excavator's thermal management system operates in the first operating mode when the battery pack 9 is in high-power discharge mode or when the ambient temperature is higher than a first set temperature. In high-power discharge mode, the high power is set according to industry standards and engineering practices. The first set temperature is, for example, 48℃ to 52℃.

[0130] When battery pack 9 is subjected to prolonged high-power discharge or continuous operation in a high-temperature environment, the internal temperature of the battery cells rises significantly, which can easily lead to thermal runaway. If the temperature detected by the first pressure and temperature detection element 161 exceeds the upper limit of the battery pack 9's operating temperature, compressor 1 will start. The refrigerant will flow through condenser 2, first electronic expansion valve 41, and first evaporator 51, finally returning to compressor 1. The battery cooling water circulation path is: first water pump 81, heater 7, first evaporator 51, plate heat exchanger 10, third switching valve 112a (inflow), b (outflow), battery pack 9, and first water pump 81. The refrigerant absorbs heat during evaporation in the first evaporator 51, reducing the internal temperature of battery pack 9.

[0131] See Figure 3In some embodiments, the thermal management system of the electric excavator includes a second operating mode, namely a low-temperature heat dissipation mode for the battery pack 9. When the thermal management system is in the second operating mode: the second branch S22 of the motor cooling flow path S2 is connected in series with the heat exchange flow path S1 to form a loop, thereby cooling the battery pack 9. Specifically, the thermal management system is in the second operating mode when the battery pack 9 is charging and the ambient temperature is lower than a second set temperature. The second set temperature is, for example, 8°C to 12°C.

[0132] When the ambient temperature is lower than the second set temperature and the battery is charging: During high-power charging, the internal cell temperature of the battery pack 9 rises. To ensure battery safety and charging efficiency, the cell temperature should be maintained at a specified temperature for the battery pack 9. Specifically, in this embodiment, the cooling water temperature during charging is required to be the second set temperature. The first water pump 81 starts, and the cooling water flows sequentially through the heater 7, the first evaporator 51, the plate heat exchanger 10, the third switching valve 112a (inflow), c (outflow), the first one-way valve 121, the second switching valve 13c (inflow), b (outflow), the radiator 14, the third switching valve 112d (inflow), b (outflow), the battery pack 9, and finally returns to the inlet of the first water pump 81. The compressor 1 and other chiller components are not started; the low-energy radiator 14 is used to cool the battery pack 9.

[0133] When the battery is charged at high power in a low-temperature environment, a large amount of heat is generated inside the battery cell. Due to the temperature difference with the environment, the large-area heat sink 14 of the heat exchange flow path S1 and the motor cooling flow path S2 are connected in series by the third switching valve 112 to dissipate heat from the battery pack 9. Furthermore, the flow path is not connected in series with the electric drive system, resulting in low pipe resistance, low water pump load, high efficiency, and low energy consumption. Additionally, the cooling circulating water path does not pass through the electric drive system components, has a short flow path, low pipe resistance, and rapid cooling.

[0134] See Figure 4 In some embodiments, the thermal management system of the electric excavator includes a third operating mode, namely a battery pack 9 heating mode. When the electric excavator's thermal management system is in the third operating mode: the first branch S21 and the third branch S23 of the motor cooling flow path S2 are connected in series to form a loop, and the plate heat exchanger 10 is located in this loop to utilize the heat from the motor cooling flow path S2 to heat the battery pack 9. Specifically, the electric excavator's thermal management system is in the third operating mode when the ambient temperature is lower than a second set temperature and the battery pack 9 is started. The second set temperature is, for example, 8°C to 12°C.

[0135] Under low-temperature conditions, the internal resistance of the battery cell increases, limiting output efficiency. When the excavator starts at low temperatures, the internal temperature of the battery cell is low. The temperature detected by the first pressure and temperature detection element 161 is lower than the second set temperature, which is the lower limit of the operating temperature of the battery pack 9. The first water pump 81 and the heater 7 start, and the water temperature rises rapidly. The water flows through the first water pump 81, heater 7, first evaporator 51, plate heat exchanger 10, and third switching valve 112a into the battery pack 9, and finally back to the inlet of the first water pump 81. As the boom electric drive system cooling path 18, the turntable electric drive system cooling path 19, or the travel electric drive system cooling path 20 continues to operate, the temperature of the electric drive system rises. At this time, the second water pump 82 starts, and the cooling water flows through the diversion valve 151, the first flow switch valve 171, the second flow switch valve 172, the third flow switch valve 173, the boom electric drive system cooling path 18, the turntable electric drive system cooling path 19, the travel electric drive system cooling path 20, the confluence valve 152, and the first switching valve 111. A flows in, b flows out, plate heat exchanger 10, first switching valve 111d flows in, c flows out, second check valve 122, second switching valve 13, c and a of second switching valve 13 are connected, bypassing radiator 14. At this time, the temperature of the second pressure and temperature detection element 162 is higher than the detection temperature of the first pressure and temperature detection element 161. The third pressure and temperature detection element 163, the fourth pressure and temperature detection element 164, and the fifth pressure and temperature detection element 165 have not reached the corresponding electric drive system heat dissipation temperature standard. The waste heat of the electric drive system is used to heat the battery pack 9, reducing the power of the high-energy-consuming heater 7. The water circuit of the electric drive system and the water circuit of the battery pack 9 use plate heat exchanger 10 for heat conduction to reduce the thermal shock of the battery pack 9. When the temperature of the battery pack 9 reaches the optimal operating temperature or the temperature of the electric drive system reaches the heat dissipation requirement temperature, a flows in of the first switching valve 111, c flows out of the first switching valve 111, and the heat exchange ends.

[0136] See Figure 5 In some embodiments, the thermal management system of the electric excavator includes a fourth operating mode, namely a motor cooling mode under low-temperature conditions. When the electric excavator's thermal management system is in the fourth operating mode: the first branch S21 and the second branch S22 of the motor cooling flow path S2 are connected in series and form a loop, so that the radiator 14 of the second branch S22 can be used to cool the motor in the first branch S21. Specifically, when the ambient temperature is lower than a third set temperature and the motor on the first branch S21 is in operation, the electric excavator's thermal management system is in the fourth operating mode. The third set temperature is, for example, 43℃-47℃.

[0137] Electric excavators can be specifically unmanned fully electric excavators. The boom luffing, turntable rotation, and travel of electric excavators are all driven by electric motors, and the working conditions are more severe than those of traditional excavators, especially in high-temperature environments. The motors and their controllers need to maintain a reasonable operating temperature. When the ambient temperature is lower than the third set temperature, the third pressure and temperature detection element 163, the fourth pressure and temperature detection element 164, or the fifth pressure and temperature detection element 165 reaches the upper limit of the set temperature of the electric drive system. The second water pump 82 starts, and the cooling water flows sequentially through the diversion valve 151, the first flow switch valve 171, the second flow switch valve 172, the boom electric drive system cooling flow path 18, the turntable electric drive system cooling flow path 19 or the travel electric drive system cooling flow path 20, the confluence valve 152, the third switching valve 112 (a) inflow, the third switching valve 112 (c) outflow, the second check valve 122, the second switching valve 13 (c) inflow, the second switching valve 13 (b) outflow, the radiator 14, the fourth switching valve 113 (d) inflow, the fourth switching valve 113 (b) outflow, and finally back to the second water pump 82.

[0138] See Figure 6 In some embodiments, such as the aforementioned electric excavator thermal management system, the electric excavator thermal management system includes a fifth operating mode, namely, a motor cooling mode under high-temperature conditions in the middle range. When the electric excavator thermal management system is in the fifth operating mode: the first branch S21 and the second branch S22 of the motor cooling flow path S2 are connected in series, and the first branch S21 exchanges heat with the refrigerant circulation loop S3, so as to utilize the radiator 14 of the second branch S22 and the refrigerant circulation loop S3 to cool the motor of the first branch S21.

[0139] Specifically, when the ambient temperature exceeds the third set temperature but is lower than the outlet water temperature of the first branch S21, the motor on the first branch S21 is in working condition, and the thermal management system of the electric drive excavator is in the fifth working mode.

[0140] When the ambient temperature exceeds the third set temperature but falls below the outlet water temperature of the electric drive system, the heat exchange efficiency of radiator 14 decreases. If the radiator 14 has a large area, it will affect the overall space of the unit. At this time, compressor 1 starts, refrigerant flows through condenser 2, the shut-off valve opens, and the refrigerant is distributed according to the needs of the electric drive system and battery heat dissipation. After passing through the shut-off valve, the refrigerant enters the second electronic expansion valve 42 and the second evaporator 52, and finally flows back to compressor 1. At the same time, the flow path of the electric drive system's heat dissipation cooling pipes before the fourth switching valve 113 is the same as the above-mentioned condition where the ambient temperature is lower than the third set temperature. The d-flow into the fourth switching valve 113 flows out through the c-flow of the fourth switching valve 113, the outlet connects to the second evaporator 52, and after the water exits, it connects to the a-flow into the fourth switching valve 113, the b-flow out, and finally flows back to the second water pump 82.

[0141] See Figure 7In some embodiments, the thermal management system of the electric excavator includes a sixth operating mode.

[0142] When the thermal management system of the electric drive excavator is in the sixth working mode: the first branch S21 and the third branch S23 of the motor cooling flow path S2 are connected in series, and the first branch S21 exchanges heat with the refrigerant circulation loop S3, so as to use the heat exchange effect of the radiator 14 of the second branch S22 of the motor cooling flow path S2 and the refrigerant circulation loop S3 to cool down the motor of the first branch S21.

[0143] Specifically, when the ambient temperature is not lower than the outlet water temperature of the first branch S21 of the motor cooling flow path S2, the motor on the first branch S21 is in working condition, and the thermal management system of the electric drive excavator is in the sixth working mode.

[0144] When the ambient temperature exceeds the outlet water temperature of the electric drive system, the refrigerant flow path is the same as described above. The cooling pipes of the electric drive system will bypass radiator 14, and the subsequent flow path is the same as the above operating condition. At this time, compressor 1 starts, refrigerant flows through condenser 2, shut-off valve 3 opens, and refrigerant is distributed according to the needs of the electric drive system and battery heat dissipation. After flowing through shut-off valve 3, the refrigerant enters the second electronic expansion valve 42 and the second evaporator 52, and finally flows back to compressor 1. At the same time, the flow path of the electric drive system's heat dissipation cooling pipes before the fourth switching valve 113 is the same as the above operating condition where the ambient temperature is lower than the third set temperature. Flow into the fourth switching valve 113 is d-flow and c-flow, the outlet is connected to the second evaporator 52, and after the water exits, it is connected to the fourth switching valve 113a-flow and b-flow, and finally flows back to the second water pump 82.

[0145] The above technical solution can further expand the operating range, especially under extreme high temperatures, by using the compressor 1 electric drive system for heat dissipation to ensure the operating performance of the main unit.

[0146] This invention also provides an electric drive excavator, including the electric drive excavator thermal management system provided by any of the technical solutions of this invention. The electric drive excavator, having the electric drive excavator thermal management system described above, also possesses the technical effects described above.

[0147] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0148] In the description of this invention, each technical feature may be combined with other technical features where feasible.

[0149] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electric drive excavator thermal management system, characterized by, include: The heat flow path to be replaced (S1) includes the battery pack (9); The motor cooling flow path (S2) includes a first branch (S21), a second branch (S22), and a third branch (S23); the second branch (S22) and the third branch (S23) are arranged in parallel; the first branch (S21) can optionally form a liquid flow loop with one of the second branch (S22) and the third branch (S23); and The refrigerant circulation loop (S3) includes a compressor (1), a condenser (2), a first evaporator (51), a second evaporator (52), and a shut-off valve (3); the refrigerant circulation loop (S3) is configured to achieve, through the shut-off valve (3): the compressor (1), the condenser (2), and the first evaporator (51) form a first refrigerant loop; or, the compressor (1), the condenser (2), and the second evaporator (52) form a second refrigerant loop; The motor cooling flow path (S2) and the refrigerant circulation loop (S3) can selectively adjust the temperature of the battery pack (9); the refrigerant circulation loop (S3) can selectively adjust the temperature of the motor cooling flow path (S2).

2. The electric drive excavator thermal management system of claim 1, wherein, The battery pack (9) of the heat exchange flow path (S1) includes a first cooling water flow channel; the first cooling water flow channel includes a first inlet and a first outlet; The heat exchange path (S1) also includes: The first water pump (81) includes a second inlet and a second outlet; the second inlet of the first water pump (81) is connected to the first outlet of the first cooling water channel; and The heater (7) includes a third inlet and a third outlet; the third inlet of the heater (7) is connected to the second outlet of the first water pump (81); The first evaporator (51) includes a first heat exchange channel and a second heat exchange channel. The first heat exchange channel is connected to the third outlet of the heater (7) and the first inlet of the first cooling water channel of the battery pack (9). The second heat exchange channel is connected to the condenser (2) and the compressor (1). The first evaporator (51) realizes the heat exchange between the refrigerant flow path and the heat exchange path (S1) to be cooled, thereby cooling the battery pack (9) of the heat exchange path (S1).

3. The thermal management system for an electric excavator according to claim 2, characterized in that, The heat exchange path (S1) also includes: The plate heat exchanger (10) includes a third heat exchange channel and a fourth heat exchange channel. The third heat exchange channel is located between the first heat exchange channel of the first evaporator (51) and the first water inlet of the battery pack (9). The fourth heat exchange channel is configured to switch between the following states: disconnected from the motor cooling channel (S2) and connected in series with the motor cooling channel (S2). The heat exchange between the heat exchange path (S1) and the motor cooling path (S2) is achieved through the plate heat exchanger (10) to heat the battery pack (9) in the heat exchange path (S1).

4. The thermal management system for an electric excavator according to claim 3, characterized in that, Also includes: The first switching valve (111) includes a first port, a second port, a third port and a fourth port; the first port and the third port are located in the first branch (S21); the second port is connected to the first end of the fourth heat exchange channel of the plate heat exchanger (10), and the fourth port is connected to the second end of the fourth heat exchange channel of the plate heat exchanger (10); The first switching valve (111) includes a first valve position and a second valve position; When the first switching valve (111) is in the first valve position, the first port and the second port are connected, and the third port and the fourth port are connected; When the first switching valve (111) is in the second valve position, the first port and the third port are connected, and the second port and the fourth port are connected.

5. The thermal management system for an electric excavator according to claim 3, characterized in that, The motor cooling flow path (S2) also includes: The second switching valve (13) includes a fifth port, a sixth port and a seventh port; the fifth port is connected to the first branch (S21), the sixth port is connected to the second branch (S22), and the seventh port is connected to the third branch (S23); The second switching valve (13) includes a third valve position and a fourth valve position; When the second switching valve (13) is in the third valve position, the sixth port and the seventh port are connected; When the second switching valve (13) is in the fourth valve position, the fifth port and the seventh port are connected.

6. The thermal management system for an electric excavator according to claim 5, characterized in that, The second branch (S22) includes a radiator (14), the sixth port of the second switching valve (13) is connected to the inlet of the radiator (14), and the outlet of the radiator (14) is connected to the first branch (S21) of the motor cooling flow path (S2).

7. The thermal management system for an electric excavator according to claim 6, characterized in that, Also includes: The third switching valve (112) includes a first connection port, a second connection port, a third connection port and a fourth connection port; the first connection port is connected to the end of the third heat exchange channel of the plate heat exchanger (10) away from the first evaporator (51); the second connection port is connected to the first water inlet of the battery pack (9); the third connection port is connected to the seventh port of the second switching valve (13); and the fourth connection port is connected to the outlet of the radiator (14).

8. The thermal management system for an electric excavator according to claim 6, characterized in that, The second evaporator (52) includes: The fifth heat exchange channel is located between the condenser (2) and the compressor (1); and The sixth heat exchange channel is connected to the heater (7) and the first inlet of the first cooling water channel. The sixth heat exchange channel is configured to switch between the following states: disconnected from the first branch (S21) of the motor cooling channel (S2) and connected in series with the first branch (S21).

9. The thermal management system for an electric excavator according to claim 8, characterized in that, Also includes: The fourth switching valve (113) includes a first connection port, a second connection port, a third connection port and a fourth connection port; the second connection port and the fourth connection port are located in the first branch (S21) and are located downstream of the radiator (14); the first connection port is connected to the first end of the fourth heat exchange channel of the plate heat exchanger (10), and the third connection port is connected to the second end of the fourth heat exchange channel; The fourth switching valve (113) includes a fifth valve position and a sixth valve position; When the fourth switching valve (113) is in the fifth valve position, the first connecting port and the second connecting port are connected, and the third connecting port and the fourth connecting port are connected; When the fourth switching valve (113) is in the sixth valve position, the first connection port and the third connection port are connected, and the second connection port and the fourth connection port are connected.

10. The thermal management system for an electric excavator according to claim 1, characterized in that, The thermal management system of the electric drive excavator includes a first working mode; The first working mode: the refrigerant circulation loop (S3) exchanges heat with the heat exchange flow path (S1) to cool the battery pack (9).

11. The thermal management system for an electric excavator according to claim 1, characterized in that, When the battery pack (9) is in high-power discharge mode or the ambient temperature is higher than the first set temperature, the thermal management system of the electric drive excavator is in the first working mode.

12. The thermal management system for an electric excavator according to claim 1, characterized in that, The thermal management system of the electric drive excavator includes a second operating mode; The second working mode: the second branch (S22) of the motor cooling flow path (S2) is connected in series with the heat exchange flow path (S1) to form a loop, so as to cool the battery pack (9).

13. The thermal management system for an electric excavator according to claim 1, characterized in that, When the battery pack (9) is in a charging state and the ambient temperature is lower than the second set temperature, the thermal management system of the electric drive excavator is in the second working mode.

14. The thermal management system for an electric excavator according to claim 1, characterized in that, The thermal management system of the electric drive excavator includes a third working mode; The third working mode: the first branch (S21) and the third branch (S23) of the motor cooling flow path (S2) are connected in series and form a loop, and the plate heat exchanger (10) is located in the loop to use the heat of the motor cooling flow path (S2) to heat the battery pack (9).

15. The thermal management system for an electric excavator according to claim 1, characterized in that, When the ambient temperature is lower than the second set temperature and the battery pack (9) is started, the thermal management system of the electric drive excavator is in the third working mode.

16. The thermal management system for an electric excavator according to claim 1, characterized in that, The thermal management system of the electric drive excavator includes a fourth operating mode; The fourth working mode: the first branch (S21) and the second branch (S22) of the motor cooling flow path (S2) are connected in series and form a loop, so as to use the heat sink (14) of the second branch (S22) to cool down the motor of the first branch (S21).

17. The thermal management system for an electric excavator according to claim 1, characterized in that, When the ambient temperature is lower than the third set temperature and the motor on the first branch (S21) is in working condition, the thermal management system of the electric drive excavator is in the fourth working mode.

18. The thermal management system for an electric excavator according to claim 1, characterized in that, The thermal management system of the electric drive excavator includes a fifth working mode; The fifth working mode: the first branch (S21) and the second branch (S22) of the motor cooling flow path (S2) are connected in series, and the first branch (S21) exchanges heat with the refrigerant circulation loop (S3) so as to use the radiator (14) of the second branch (S22) and the refrigerant circulation loop (S3) to cool down the motor of the first branch (S21).

19. The thermal management system for an electric excavator according to claim 1, characterized in that, When the ambient temperature exceeds the third set temperature and the ambient temperature is lower than the outlet water temperature of the first branch (S21), the motor on the first branch (S21) is in working condition, and the electric drive excavator thermal management system is in the fifth working mode.

20. The thermal management system for an electric excavator according to claim 1, characterized in that, The thermal management system of the electric drive excavator includes a sixth operating mode; The sixth working mode: the first branch (S21) and the third branch (S23) of the motor cooling flow path (S2) are connected in series, and the first branch (S21) exchanges heat with the refrigerant circulation loop (S3) to cool the motor of the first branch (S21) by utilizing the heat exchange effect of the radiator (14) of the second branch (S22) of the motor cooling flow path (S2) and the refrigerant circulation loop (S3).

21. The thermal management system for an electric excavator according to claim 1, characterized in that, When the ambient temperature is not lower than the outlet water temperature of the first branch (S21) of the motor cooling flow path (S2), the motor on the first branch (S21) is in working condition, and the electric drive excavator thermal management system is in the sixth working mode.

22. The thermal management system for an electric excavator according to claim 1, characterized in that, The first branch (S21) of the motor cooling flow path (S2) includes: Second water pump (82); A diversion valve (151) is located downstream of and connected to the second water pump (82). The diversion valve (151) includes a first working port, a second working port, and a third working port arranged in parallel. The diversion valve (151) is configured to divert the fluid output from the second water pump (82). The boom electric drive system cooling flow path (18) is connected to the first working port and is located downstream of the first working port; The cooling flow path (19) of the turntable electric drive system is connected to the second working port and is located downstream of the second working port; The cooling flow path (20) of the electric drive system is connected to the third working port and located downstream of the third working port; and The confluence valve (152) is located downstream of the boom electric drive system cooling flow path (18), the turntable electric drive system cooling flow path (19), and the travel electric drive system cooling flow path (20), and is connected to the boom electric drive system cooling flow path (18), the turntable electric drive system cooling flow path (19), and the travel electric drive system cooling flow path (20) to achieve confluence.

23. An electrically driven excavator, characterized in that, Includes the thermal management system for electric excavators as described in any one of claims 1-22.

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