Electric engineering machinery thermal management system, control method thereof and electric engineering machinery

Abstract

The invention relates to an electric engineering machinery heat management system and a control method thereof and electric engineering machinery, the heat management system comprises a battery pack, a first liquid storage tank, a first liquid pump, a plurality of first air conditioning units arranged in parallel, a heat dissipation group and a first controller, the battery pack provides driving force, and the first liquid storage tank stores a circulating medium; the first liquid pump is communicated with the first liquid storage tank, the first liquid pump and the battery pack are connected to form a first circulation loop, the first liquid pump drives a circulation medium to flow through the battery pack, so that the circulation medium exchanges heat with the battery pack, and each first air conditioning unit comprises a compressor, a condenser, a first throttling device and a first evaporator; the first air conditioning units reduce the temperature of a circulating medium in the first circulating loop, the heat dissipation sets dissipate heat of condensers in the first air conditioning units and / or reduce the temperature of the circulating medium flowing through the battery pack, and the first controller controls the multiple first air conditioning units and the heat dissipation sets to be started and stopped according to the temperature of the battery pack.

Description

Technical Field

[0001] This disclosure relates to the field of engineering machinery technology, and in particular to an electric engineering machinery thermal management system and its control method, and electric engineering machinery. Background Technology

[0002] With the advancement of zero-carbon goals in mining areas both domestically and internationally, the development of pure electric construction machinery is rapid. Currently, large-tonnage pure electric construction machinery used in mines in tropical regions is showing a rapid development trend, with increasing emphasis placed on charging speed.

[0003] Megawatt-level fast charging technology for power batteries is becoming increasingly popular in construction machinery, with a maximum charging time of half an hour. This also results in a huge demand for cooling capacity during charging (usually greater than 100kW). The cooling demand during charging is 3 to 5 times that of the cooling demand during vehicle operation. At the same time, it is necessary to cope with high ambient temperatures (sometimes as high as 55°C), which poses a great challenge to the thermal management system.

[0004] Currently, for megawatt-class pure electric mining machinery, the main solution for its thermal management system is to cool each battery pack individually. This solution requires a large number of heat exchangers, resulting in low system heat transfer efficiency, which affects the overall vehicle energy consumption, and also incurs significant investment costs.

[0005] It should be noted that the information disclosed in the background section of this disclosure is intended only to enhance the understanding of the overall background of this disclosure, and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art. The foregoing statements are only intended to provide background information in relation to this application and do not necessarily constitute prior art. Summary of the Invention

[0006] This disclosure provides an electric engineering machinery thermal management system and its control method, as well as the electric engineering machinery.

[0007] According to a first aspect of this disclosure, an electric engineering machinery thermal management system is provided, comprising:

[0008] The battery pack is configured to provide driving force;

[0009] The first storage tank is configured to store the circulating medium;

[0010] A first liquid pump is connected to a first liquid storage tank. The first liquid pump and the battery pack are connected to form a first circulation loop. The first liquid pump is configured to drive the circulation medium to flow through the battery pack so that the circulation medium and the battery pack can exchange heat.

[0011] Multiple first air conditioning units are connected in parallel. Each first air conditioning unit includes a compressor, a condenser, a first throttling device, and a first evaporator. The refrigerant flows between the compressor, the condenser, the first throttling device, and the first evaporator to form a refrigerant circulation loop. The first air conditioning unit is configured to reduce the temperature of the circulating medium in the first circulation loop.

[0012] The heat dissipation unit is configured to dissipate heat from the condenser in the first air conditioning unit and / or reduce the temperature of the circulating medium flowing through the battery pack; and

[0013] A first controller is connected to multiple first air conditioning units and a heat dissipation unit via signals. The first controller is configured to control the start and stop of the multiple first air conditioning units and the heat dissipation unit based on the temperature of the battery pack.

[0014] In some embodiments, a plurality of first evaporators are connected in parallel to a first circulation loop, and the refrigerant in the first evaporator exchanges heat with the circulating medium in the first circulation loop.

[0015] In some embodiments, the heat dissipation assembly includes:

[0016] The second storage tank is configured to store the circulating medium;

[0017] First heat exchanger;

[0018] A second liquid pump is connected to a second liquid storage tank. The second liquid pump and the first heat exchanger are connected to form a second circulation loop. Multiple condensers are connected in parallel to the second circulation loop.

[0019] An air circulation device is configured to accelerate the heat exchange between the circulating medium in the first heat exchanger and the outside air.

[0020] In some embodiments, the heat dissipation assembly includes:

[0021] The second storage tank is configured to store the circulating medium;

[0022] First heat exchanger;

[0023] The second liquid pump is connected to the second liquid storage tank. The battery pack, the first liquid pump, the second liquid pump, and the first heat exchanger are connected to form a third circulation loop.

[0024] An air circulation device is configured to accelerate the heat exchange between the circulating medium in the first heat exchanger and the outside air.

[0025] In some embodiments, the heat dissipation assembly includes a plurality of air circulation devices, and a first controller is configured to control the start and stop of the plurality of air circulation devices according to the temperature of the battery pack.

[0026] In some embodiments, the thermal management system further includes a first control valve disposed in a first circulation loop and a second control valve disposed in a third circulation loop. The first control valve is connected to a first liquid pump, a first evaporator, and a second control valve, and the second control valve is connected to a second liquid pump, a condenser, and the first control valve.

[0027] In some embodiments, the thermal management system further includes a motor and a second controller for controlling the motor, wherein a heat dissipation group is configured to reduce the temperature of the motor and the second controller.

[0028] In some embodiments, the thermal management system further includes a motor and a second controller for controlling the motor. The motor, the second controller, the second liquid pump, and the first heat exchanger are connected to form a fourth circulation loop to remove heat from the motor and the second controller through a circulating medium flowing through the motor and the second controller.

[0029] In some embodiments, the thermal management system further includes a second control valve and a third control valve disposed in the second circulation loop, the second control valve being connected to the second liquid pump, the condenser and the motor, and the third control valve being connected to the first heat exchanger, the condenser and the motor.

[0030] In some embodiments, the thermal management system further includes a cab, a second throttling device, a second evaporator, and an air supply device. The compressor, condenser, second throttling device, and second evaporator constitute a second air conditioning unit, and the air supply device is configured to blow cold air around the second evaporator into the cab.

[0031] In some embodiments, the thermal management system further includes a fourth control valve and a fifth control valve, the fourth control valve being connected to the compressor inlet, the first evaporator and the second evaporator, and the fifth control valve being connected to the condenser, the first throttling device and the second throttling device.

[0032] In some embodiments, the thermal management system further includes a cab, a second heat exchanger, and an air supply device. The battery pack, the first liquid pump, and the second heat exchanger are connected to form a fifth circulation loop to transfer heat from the battery pack to the second heat exchanger via a circulation medium. The air supply device is configured to deliver hot air from around the second heat exchanger into the cab.

[0033] In some embodiments, the thermal management system further includes a first control valve and a sixth control valve disposed in a first circulation loop, and a second control valve and a seventh control valve disposed in a second circulation loop. The first control valve is connected to a first liquid pump, a first evaporator, and a second control valve. The second control valve is connected to a second liquid pump, a condenser, and the first control valve. The sixth control valve is connected to a battery pack, a first evaporator, and a second heat exchanger. The seventh control valve is connected to a second liquid pump, a first heat exchanger, and a second heat exchanger.

[0034] In some embodiments, the thermal management system further includes a cab, a second heat exchanger, an air supply device, a motor, and a second controller for controlling the motor. The motor, the second controller, the second liquid pump, and the second heat exchanger are connected to form a sixth circulation loop to transfer heat generated by the motor and the second controller to the second heat exchanger via a circulation medium. The air supply device is configured to deliver hot air around the second heat exchanger into the cab.

[0035] In some embodiments, the thermal management system further includes a second control valve, a third control valve, and a seventh control valve disposed in a second circulation loop, and an eighth control valve disposed in a sixth circulation loop. The second control valve is connected to a second liquid pump, a condenser, and a motor. The third control valve is connected to a first heat exchanger, a condenser, a motor, and the eighth control valve. The seventh control valve is connected to the second liquid pump, the first heat exchanger, and the second heat exchanger. The eighth control valve is connected to a battery pack, the third control valve, and the second heat exchanger.

[0036] In some embodiments, the thermal management system further includes a motor and a second controller for controlling the motor. The motor, the second controller, the battery pack, and the first liquid pump are connected to form a seventh circulation loop to transfer the heat generated by the motor and the second controller to the battery pack through a circulation medium.

[0037] In some embodiments, the thermal management system further includes a motor, a second controller for controlling the motor, a first control valve and a sixth control valve disposed in a first circulation loop, and a second control valve and a third control valve disposed in a second circulation loop. The first control valve is connected to a first liquid pump, a first evaporator, and the second control valve. The second control valve is connected to a second liquid pump, a condenser, the first control valve, and the motor. The third control valve is connected to a first heat exchanger, a condenser, the motor, and the sixth control valve. The sixth control valve is connected to a battery pack, the first evaporator, and the third control valve.

[0038] According to a second aspect of this disclosure, an electric construction machinery is provided, including the aforementioned electric construction machinery thermal management system.

[0039] According to a third aspect of this disclosure, a control method for the above-described thermal management system of electric engineering machinery is provided, the control method comprising:

[0040] When the battery pack is in charging mode and the temperature of the circulating medium flowing through the battery pack 1 is not less than the first preset value, the first liquid pump is turned on to make the first circulation loop in a flowing state.

[0041] Start all of the first air conditioning units and heat dissipation units.

[0042] In some embodiments, the control method includes:

[0043] When the battery pack is in charging mode and the temperature of the circulating medium flowing through the battery pack is less than the first preset value, the first liquid pump is turned on to make the first circulation loop in a flowing state.

[0044] Shut down all of the first-level air conditioning units and heat dissipation units.

[0045] In some embodiments, the control method includes:

[0046] When the battery pack is in driving condition and the highest temperature of each cell in the battery pack is not less than the second preset value, the first liquid pump is turned on to make the first circulation loop flow, and all the first air conditioning units and heat dissipation units are started. At the same time, the ambient temperature T of the battery pack is detected.

[0047] When T≥T1, keep all first air conditioning units and heat dissipation units in the open state;

[0048] The formula for calculating T1 is:

[0049]

[0050] in, This refers to the highest temperature of the environment in which the electric construction machinery operates. The maximum cooling capacity required for vehicle operation is given by k, which is the temperature coefficient of the cooling capacity of a single compressor.

[0051] When T2≤T<T1, keep half of the first air conditioning units on and turn off the other half of the first air conditioning units, while keeping the heat dissipation units on.

[0052] The formula for calculating T2 is:

[0053]

[0054] in, The maximum cooling capacity required for vehicle operation. The temperature of the circulating medium required by the battery pack. The specific heat capacity of the circulating medium. The density of the circulating medium, The flow rate of the first loop is... The specific heat capacity of air. For the density of air, This refers to the external airflow of the heat dissipation unit.

[0055] When T < T2, all of the first air conditioning units are turned off, while the heat dissipation units are kept on.

[0056] In some embodiments, the control method includes:

[0057] When the battery pack is in driving condition, and the highest temperature of each cell in the battery pack is less than the second preset value, and the difference between the highest temperature tmax and the lowest temperature tmin of each cell is greater than or equal to the third preset value, all of the first air conditioning units and heat dissipation units are turned off, and the first liquid pump is turned on to keep the first circulation loop in a flowing state until the difference between the highest temperature tmax and the lowest temperature tmin of each cell is detected to be less than or equal to the fourth preset value, at which point the first liquid pump is turned off.

[0058] In some embodiments, the thermal management system further includes a driver's cab, a second heat exchanger, an air supply device, a motor, and a second controller for controlling the motor. A battery pack, a first liquid pump, and a second heat exchanger are connected to form a fifth circulation loop. The motor, the second controller, the second liquid pump, and the second heat exchanger are connected to form a sixth circulation loop. The control method includes:

[0059] When the battery pack is charging, the fifth cycle circuit is activated to use the waste heat of the battery pack to heat the cab.

[0060] When the battery pack is in driving condition, the fifth and sixth circulation circuits are activated, and the waste heat from the battery pack and motor is used to heat the cab.

[0061] Based on the above technical solution, this disclosure utilizes a circulating medium for heat exchange in the battery pack and multiple parallel-connected first air conditioning units for cooling the circulating medium. The heat dissipation group can be used to dissipate heat from the condenser in the first air conditioning unit and / or to reduce the temperature of the circulating medium flowing through the battery pack, thus realizing multiple uses of the heat dissipation group, effectively reducing the number of heat dissipation groups, reducing investment costs, simplifying the system structure, improving the system coupling, and also helping to improve the system heat transfer efficiency and improve the overall vehicle energy consumption. Attached Figure Description

[0062] The accompanying drawings, which are included to provide a further understanding of this disclosure and form part of this application, illustrate exemplary embodiments of this disclosure and are used to explain this disclosure, but do not constitute an undue limitation of this disclosure. In the drawings:

[0063] Figure 1 The diagram shows a structural schematic of some embodiments of the thermal management system for electric construction machinery provided in this disclosure.

[0064] Figure 2 Flowcharts of some embodiments of the electric engineering machinery thermal management system provided in this disclosure.

[0065] In the picture:

[0066] 1. Battery pack; 2. First liquid storage tank; 3. First liquid pump;

[0067] 4. First air conditioning unit; 41. Compressor; 42. Condenser; 43. First throttling device; 44. First evaporator;

[0068] 5. Heat dissipation assembly; 51. Second liquid storage tank; 52. First heat exchanger; 53. Second liquid pump; 54. Air circulation device;

[0069] 6. First controller;

[0070] 71. First control valve; 72. Second control valve; 73. Third control valve; 74. Fourth control valve; 75. Fifth control valve; 76. Sixth control valve; 77. Seventh control valve; 78. Eighth control valve;

[0071] 8. Electric motor; 81. First electric motor; 82. Second electric motor;

[0072] 9. Second controller; 10. Driver's cab; 11. Second throttling device; 12. Second evaporator; 13. Air supply device; 14. Second heat exchanger;

[0073] 100, First loop; 200, Second loop; 300, Third loop; 400, Fourth loop; 500, Fifth loop; 600, Sixth loop; 700, Seventh loop. Detailed Implementation

[0074] The technical solutions in the embodiments of this disclosure will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0075] In the description of this disclosure, it should be understood that the terms "center," "lateral," "longitudinal," "front," "rear," "left," "right," "upper," "lower," "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, and are only for the convenience of describing this disclosure and 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, and therefore should not be construed as a limitation on the scope of protection of this disclosure.

[0076] like Figure 1As shown, in some embodiments of the electric engineering machinery thermal management system provided in this disclosure, the thermal management system includes a battery pack 1, a first liquid storage tank 2, a first liquid pump 3, a first air conditioning unit 4, a heat dissipation group 5, and a first controller 6. The battery pack 1 is configured to provide driving force, the first liquid storage tank 2 is configured to store circulating medium, the first liquid pump 3 is connected to the first liquid storage tank 2, and the first liquid pump 3 and the battery pack 1 are connected to form a first circulation loop 100. The first liquid pump 3 is configured to drive the circulating medium to flow through the battery pack 1 so that the circulating medium and the battery pack 1 exchange heat. Multiple first air conditioning units 4 are arranged in parallel, and each first air conditioning unit 4 includes a pressure... The compressor 41, condenser 42, first throttling device 43, and first evaporator 44 are configured to form a refrigerant circulation loop. The first air conditioning unit 4 is configured to reduce the temperature of the circulating medium in the first circulation loop 100. The heat dissipation unit 5 is configured to dissipate heat from the condenser 42 in the first air conditioning unit 4 and / or reduce the temperature of the circulating medium flowing through the battery pack 1. The first controller 6 is signal-connected to multiple first air conditioning units 4 and heat dissipation unit 5. The first controller 6 is configured to control the start and stop of multiple first air conditioning units 4 and heat dissipation unit 5 according to the temperature of the battery pack 1.

[0077] Among them, battery pack 1 can be understood as a battery pack composed of multiple battery modules, and each battery module includes multiple cells.

[0078] The first liquid storage tank 2 is used to store the circulating medium. The circulating medium on the first circulation loop 100 can enter the first liquid storage tank 2 or flow out of the first liquid storage tank 2.

[0079] In some embodiments, the first liquid storage tank 2 can be an expansion tank, which uses its own pressure to achieve the entry and exit of the circulating medium, and is conducive to ensuring the pressure stability of the first circulation loop 100.

[0080] The circulating medium in the first circulation loop 100 can be water or other flowing liquids with heat exchange function.

[0081] The first liquid pump 3 is used to drive the flow of the circulating medium, so that the circulating medium can circulate in the first circulation loop 100 and enter the battery pack 1 so that the circulating medium can exchange heat with the battery pack 1, such as removing heat from the battery pack 1 or heating the battery pack 1.

[0082] In some embodiments, the battery pack 1 is provided with a conduit inside or outside. The conduit may be wrapped around the outer periphery of the battery cell or inserted between multiple battery cells so that when the circulating medium flows through the conduit, it can exchange heat with the battery pack 1 to remove the heat generated by the battery pack 1, or heat the battery pack 1 when the ambient temperature is low, thereby improving the charging efficiency and safety performance of the battery pack 1.

[0083] The first liquid pump 3 is connected to the battery pack 1 to form a first circulation loop 100. This means that the inlet of the first liquid pump 3 is connected to one end of a pipe installed inside or outside the battery pack 1, and the outlet of the first liquid pump 3 is connected to the other end of the pipe installed inside or outside the battery pack 1, thus forming the first circulation loop 100 through the series connection of the first liquid pump 3 and the battery pack 1. The inlet and outlet of the first liquid storage tank 2 are connected to the connecting pipe between the first liquid pump 3 and the battery pack 1.

[0084] Each first air conditioning unit 4 includes a compressor 41, a condenser 42, a first throttling device 43, and a first evaporator 44. The refrigerant flows between the compressor 41, condenser 42, first throttling device 43, and first evaporator 44 to form a refrigerant circulation loop. The high-temperature, high-pressure gaseous refrigerant from the compressor 41 first enters the condenser 42, where it releases heat to form a medium-temperature, high-pressure liquid refrigerant. Then, after flowing through the first throttling device 43, its pressure drops sharply, becoming a low-temperature, low-pressure liquid mist refrigerant. Next, it enters the first evaporator 44, absorbs heat, and becomes a low-temperature, low-pressure gaseous refrigerant, finally returning to the compressor 41.

[0085] In the embodiments provided in this disclosure, the thermal management system includes multiple first air conditioning units 4, which are connected in parallel. The advantages of having multiple parallel-connected first air conditioning units 4 are twofold: first, the number of first air conditioning units 4 that can be turned on can be freely selected according to cooling demand, allowing the compressor 41 to operate in its high-efficiency range as much as possible, thus improving energy utilization efficiency; second, even if one or more of the first air conditioning units 4 stop working due to a malfunction, other working first air conditioning units 4 can still be used to achieve cooling, effectively ensuring cooling capacity and avoiding problems where cooling demand cannot be met.

[0086] In this embodiment, the number of first air conditioning units 4 is set according to cooling demand, and the cooling demand also changes as the operating conditions of battery pack 1 change, and the number of first air conditioning units 4 that are turned on can also change accordingly. For battery pack 1 containing the same number of battery modules, the number of first air conditioning units 4 is related to the cooling capacity of a single first air conditioning unit 4, and the number of first air conditioning units 4 is not necessarily equal to the number of battery modules in battery pack 1.

[0087] Compared to the solution of setting up a separate cooling unit for each battery module, the embodiments provided in this disclosure can effectively avoid the problem of a cooling unit failing to cool the battery module it is responsible for due to a malfunction. It can also reduce the number of cooling units, reduce investment costs, improve system heat transfer efficiency, and improve overall vehicle energy consumption.

[0088] In addition, since each battery module has different cooling requirements, the solution of setting up a separate cooling group for each battery module requires a compressor with different power for each battery module, which results in higher procurement costs. In contrast, the technical solution provided in this disclosure allows multiple first air conditioning units 4 set up in parallel to select compressors with the same power, resulting in lower procurement costs.

[0089] The first air conditioning unit 4 is configured to lower the temperature of the circulating medium in the first circulation loop 100. In the first air conditioning unit 4, the refrigerant in the first evaporator 44 absorbs heat and turns into a gaseous state. Therefore, the first evaporator 44 can provide cooling capacity, lower the temperature of the circulating medium in the first circulation loop 100, and thus remove the heat generated by the battery pack 1 through the circulating medium.

[0090] In the embodiments provided in this disclosure, the heat dissipation group 5 can be used alone to dissipate heat from the condenser 42 in the first air conditioning unit 4, or it can be used alone to reduce the temperature of the circulating medium flowing through the battery pack 1, or it can be used simultaneously to dissipate heat from the condenser 42 in the first air conditioning unit 4 and reduce the temperature of the circulating medium flowing through the battery pack 1. Therefore, the heat dissipation group 5 has at least the above three functions. In other words, the thermal management system uses the heat dissipation group 5 to achieve at least the above three functions, realizing multiple uses of the heat dissipation group 5. Compared with the solution of setting up a dedicated heat dissipation group for each function, the embodiments provided in this disclosure effectively reduce the number of heat dissipation groups, effectively reduce investment costs, effectively simplify the system structure, improve the system coupling, and also help improve the system heat transfer efficiency and improve the overall vehicle energy consumption.

[0091] By connecting the first controller 6 to multiple first air conditioning units 4 and heat dissipation units 5 respectively, the first controller 6 can control the start and stop of each first air conditioning unit 4 according to the temperature of the battery pack 1, and can also control the start and stop of the heat dissipation unit 5, thereby providing a variety of cooling solutions to meet cooling needs.

[0092] The first controller 6 may be a general-purpose processor, a programmable logic controller (PLC), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, or any suitable combination thereof for performing the functions described in this disclosure.

[0093] The electric engineering machinery thermal management system embodiment provided in this disclosure utilizes a circulating medium for heat exchange of the battery pack 1 and utilizes multiple parallel-connected first air conditioning units 4 for cooling the circulating medium. The heat dissipation group 5 can be used to dissipate heat from the condenser 42 in the first air conditioning unit 4 and / or to reduce the temperature of the circulating medium flowing through the battery pack 1, realizing multiple uses of the heat dissipation group 5, effectively reducing the number of heat dissipation groups 5, reducing investment costs, simplifying the system structure, improving the system coupling, and also helping to improve the system heat transfer efficiency and improve the overall vehicle energy consumption.

[0094] Furthermore, in the embodiments of the electric engineering machinery thermal management system provided in this disclosure, the heat exchange of the battery pack 1 is achieved through heat exchange with the circulating medium, rather than through air cooling. Compared to air cooling, the embodiments of this disclosure can effectively avoid problems such as easy clogging, difficulty in cleaning, and rapid degradation of heat dissipation efficiency in air-cooled systems.

[0095] In some embodiments, a plurality of first evaporators 44 are connected in parallel to the first circulation loop 100, and the refrigerant in the first evaporator 44 exchanges heat with the circulating medium in the first circulation loop 100. In this embodiment, the first air conditioning unit 4 reduces the temperature of the circulating medium in the first circulation loop 100 through the heat absorption of the refrigerant in the first evaporator 44, thereby removing the heat from the battery pack 1 through the circulating medium.

[0096] In the embodiments provided in this disclosure, the structure of the heat dissipation group 5 can be selected in various ways.

[0097] In some embodiments, the heat dissipation assembly 5 includes a second liquid storage tank 51, a first heat exchanger 52, a second liquid pump 53, and an air circulation device 54. The second liquid storage tank 51 is configured to store circulating medium. The second liquid pump 53 is connected to the second liquid storage tank 51. The second liquid pump 53 and the first heat exchanger 52 are connected to form a second circulation loop 200. A plurality of condensers 42 are connected in parallel to the second circulation loop 200. The air circulation device 54 is configured to accelerate the heat exchange between the circulating medium in the first heat exchanger 52 and the outside air.

[0098] In the above embodiment, the second liquid pump 53 and the first heat exchanger 52 are connected to form a second circulation loop 200. Multiple condensers 42 are connected in parallel to the second circulation loop 200. The circulating medium in the second circulation loop 200 can carry away the heat dissipated by the condensers 42, so as to realize the function of heat dissipation group 5 for heat dissipation of condensers 42 in the first air conditioning unit 4.

[0099] Furthermore, in the above embodiments, the condenser 42 in the first air conditioning unit 4 dissipates heat through heat exchange with the circulating medium, rather than through air cooling. Compared to air cooling, the embodiments disclosed herein can effectively avoid problems such as easy clogging, difficulty in cleaning, and rapid decline in heat dissipation efficiency in air-cooled systems.

[0100] The second liquid storage tank 51 can be an expansion tank, which uses its own pressure to achieve the entry and exit of the circulating medium, and is conducive to ensuring the pressure stability of the second circulation loop 200.

[0101] The circulating medium in the second circulation loop 200 can be water or other flowing liquids with heat exchange function.

[0102] In embodiments where the first circulation loop 100 and the second circulation loop 200 remain relatively independent, the circulation medium in the first circulation loop 100 and the circulation medium in the second circulation loop 200 may be the same or different types of liquid flow media.

[0103] In embodiments where the first circulation loop 100 and the second circulation loop 200 are connected, the circulation medium in the first circulation loop 100 and the circulation medium in the second circulation loop 200 need to be the same type of liquid flow medium.

[0104] The second liquid pump 53 is used to drive the circulation medium to circulate in the second circulation loop 200 and to enter the first heat exchanger 52 so that the circulation medium can exchange heat with the outside air in the first heat exchanger 52 to achieve the purpose of regulating the temperature of the circulation medium.

[0105] The inlet of the second liquid pump 53 is connected to the outlet of the first heat exchanger 52, and the outlet of the second liquid pump 53 is connected to the inlet of the first heat exchanger 52, thus forming a second circulation loop 200 through the series connection of the second liquid pump 53 and the first heat exchanger 52. The inlet and outlet of the second liquid storage tank 51 are connected to the connecting pipeline between the second liquid pump 53 and the first heat exchanger 52. Multiple condensers 42 are connected in parallel to the connecting pipeline between the second liquid pump 53 and the first heat exchanger 52.

[0106] The first heat exchanger 52 can be located outside the electric engineering machinery or at least partially exposed to the outside of the electric engineering machinery in order to increase the contact area between the first heat exchanger 52 and the outside air and improve the heat exchange rate of the first heat exchanger 52.

[0107] The air circulation device 54 can be a device such as a fan or blower to accelerate airflow.

[0108] In other embodiments, the heat dissipation assembly 5 includes a second liquid storage tank 51, a first heat exchanger 52, a second liquid pump 53, and an air circulation device 54. The second liquid storage tank 51 is configured to store circulating medium. The second liquid pump 53 is connected to the second liquid storage tank 51. The battery pack 1, the first liquid pump 3, the second liquid pump 53, and the first heat exchanger 52 are connected to form a third circulation loop 300. The air circulation device 54 is configured to accelerate the heat exchange between the circulating medium in the first heat exchanger 52 and the outside air.

[0109] In the above embodiment, the battery pack 1, the first liquid pump 3, the second liquid pump 53 and the first heat exchanger 52 are connected to form a third circulation loop 300. The battery pack 1 exchanges heat through the circulating medium flowing in the third circulation loop 300, and the first heat exchanger 52 can exchange heat with the circulating medium, thereby realizing the function of reducing the temperature of the circulating medium flowing through the battery pack 1 through the heat dissipation group 5.

[0110] In some other embodiments, the heat dissipation assembly 5 includes a second liquid storage tank 51, a first heat exchanger 52, a second liquid pump 53, and an air circulation device 54. The second liquid storage tank 51 is configured to store circulating medium. The second liquid pump 53 is connected to the second liquid storage tank 51. The second liquid pump 53 and the first heat exchanger 52 are connected to form a second circulation loop 200. A plurality of condensers 42 are connected in parallel to the second circulation loop 200. The battery pack 1, the first liquid pump 3, the second liquid pump 53, and the first heat exchanger 52 are connected to form a third circulation loop 300. The air circulation device 54 is configured to accelerate the heat exchange between the circulating medium in the first heat exchanger 52 and the outside air.

[0111] In the above embodiment, the heat dissipation group 5 can both remove the heat dissipated by the condenser 42 through the circulating medium, so as to realize the function of heat dissipation group 5 for the condenser 42 in the first air conditioning unit 4, and remove the heat of the circulating medium flowing in the third circulation loop 300 through the first heat exchanger 52, so as to realize the function of reducing the temperature of the circulating medium flowing through the battery pack 1 through the heat dissipation group 5.

[0112] In some embodiments, the heat dissipation assembly 5 includes a plurality of air circulation devices 54, and the first controller 6 is configured to control the start and stop of the plurality of air circulation devices 54 according to the temperature of the battery pack 1.

[0113] By setting up a first controller 6 and multiple air circulation devices 54, the number of air circulation devices 54 that can be turned on can be freely selected according to the cooling demand, thereby reducing energy consumption. At the same time, if some of the air circulation devices 54 malfunction and cannot work, the remaining air circulation devices 54 can be used to accelerate airflow and ensure normal heat dissipation.

[0114] Multiple air circulation devices 54 can be arranged on the same side of the first heat exchanger 52, on different sides of the first heat exchanger 52, or evenly arranged around the first heat exchanger 52.

[0115] In some embodiments, the thermal management system further includes a first control valve 71 disposed in the first circulation loop 100 and a second control valve 72 disposed in the third circulation loop 300. The first control valve 71 is connected to the first liquid pump 3, the first evaporator 44 and the second control valve 72, and the second control valve 72 is connected to the second liquid pump 53, the condenser 42 and the first control valve 71.

[0116] By setting the first control valve 71 and the second control valve 72, based on the first circulation loop 100 and the second circulation loop 200, the connection position of the first control valve 71 and the second control valve 72 can be adjusted to form a third circulation loop 300 by connecting the components of the first circulation loop 100 and the second circulation loop 200, thereby achieving the effect of cooling the battery pack 1 by using the heat dissipation group 5.

[0117] Specifically, in some embodiments:

[0118] The flow path of the circulating medium in the first circulation loop 100 is: battery pack 1 → first liquid pump 3 → first control valve 71 → first evaporator 44 → battery pack 1.

[0119] The refrigerant flows through the first air conditioning unit 4 as follows: compressor 41 → condenser 42 → first throttling device 43 → first evaporator 44 → compressor 41.

[0120] The flow path of the circulating medium in the second circulation loop 200 is: second liquid pump 53 → first heat exchanger 52 → condenser 42 → second control valve 72 → second liquid pump 53.

[0121] When the second circulation loop 200 is started, the heat dissipation group 5 is used to dissipate heat for the condenser 42 in the first air conditioning unit 4.

[0122] The flow path of the circulating medium in the third circulation loop 300 is: battery pack 1 → first liquid pump 3 → first control valve 71 → second control valve 72 → second liquid pump 53 → first heat exchanger 52 → battery pack 1.

[0123] When the third circulation loop 300 is started, the heat dissipation group 5 is used to reduce the temperature of the circulating medium flowing through the battery pack 1.

[0124] When both the first circulation loop 100 and the second circulation loop 200 are started, by connecting the first control valve 71 and the second control valve 72, the heat dissipation group 5 can dissipate heat for the condenser 42 in the first air conditioning unit 4 and reduce the temperature of the circulating medium flowing through the battery pack 1.

[0125] In some embodiments, the thermal management system further includes a motor 8 and a second controller 9 for controlling the motor 8, wherein the heat dissipation group 5 is configured to reduce the temperature of the motor 8 and the second controller 9.

[0126] In the above embodiments, the heat dissipation group 5 is also used to reduce the temperature of the motor 8 and the second controller 9, so as to avoid the motor 8 and the second controller 9 from having excessively high operating temperatures and affecting their lifespan.

[0127] In the above embodiments, the heat dissipation group 5 has an additional function. It can be seen that in the embodiments provided in this disclosure, the heat dissipation group 5 has at least four functions, which effectively reduces the total number of heat exchangers in the system, significantly simplifies the overall system structure, and greatly improves the coupling.

[0128] In some embodiments, the thermal management system further includes a motor 8 and a second controller 9 for controlling the motor 8. The motor 8, the second controller 9, the second liquid pump 53 and the first heat exchanger 52 are connected to form a fourth circulation loop 400 to remove the heat from the motor 8 and the second controller 9 through the circulating medium flowing through the motor 8 and the second controller 9.

[0129] When the fourth circulation loop 400 is started, the flow path of the circulating medium is: second liquid pump 53 → first heat exchanger 52 → second controller 9 → motor 8 → second liquid pump 53.

[0130] After being cooled by the first heat exchanger 52, the circulating medium carries away the heat generated by the second controller 9 and the motor 8 during operation as it flows through them, thus cooling down the second controller 9 and the motor 8 and preventing the high-temperature environment from affecting their service life.

[0131] The motor 8 may include a first motor 81 and a second motor 82. The first motor 81 may be a motor for controlling the hydraulic system, and the second motor 82 may be a motor for controlling the movement of the electric engineering machinery. The second controller 9, the first motor 81, and the second motor 82 may be connected in series in the fourth circulation loop 400.

[0132] The second controller 9 may be a general-purpose processor, a programmable logic controller (PLC), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, or any suitable combination thereof for performing the functions described in this disclosure.

[0133] In some embodiments, the thermal management system further includes a second control valve 72 disposed in the second circulation loop 200 and a third control valve 73 disposed in the second circulation loop 200. The second control valve 72 is connected to the second liquid pump 53, the condenser 42 and the motor 8, and the third control valve 73 is connected to the first heat exchanger 52, the condenser 42 and the motor 8.

[0134] By setting the second control valve 72 and the third control valve 73, a fourth circulation loop 400 can be formed by using the heat dissipation group 5 on the basis of the second circulation loop 200 and the third circulation loop 300, so as to achieve the purpose of cooling the motor 8 and the second controller 9.

[0135] Thus, the flow path of the circulating medium in the fourth circulation loop 400 is: second liquid pump 53 → first heat exchanger 52 → third control valve 73 → second controller 9 → motor 8 → second control valve 72 → second liquid pump 53.

[0136] In some embodiments, the thermal management system further includes a cab 10, a second throttling device 11, a second evaporator 12, and an air supply device 13. The compressor 41, the condenser 42, the second throttling device 11, and the second evaporator 12 constitute a second air conditioning unit, and the air supply device 13 is configured to blow cold air around the second evaporator 12 into the cab 10.

[0137] In the above embodiment, by setting the second throttling device 11 and the second evaporator 12, the compressor 41 and condenser 42 in the existing first air conditioning unit 4 can be used to form a second air conditioning unit to cool the cab 10. The second air conditioning unit uses some components of the first air conditioning unit 4, thereby effectively saving the total number of components in the thermal management system, reducing costs, and simplifying the structural layout.

[0138] The second air conditioning unit can utilize the compressor 41 and condenser 42 from any one of the multiple first air conditioning units 4.

[0139] In some embodiments, the thermal management system further includes a fourth control valve 74 and a fifth control valve 75. The fourth control valve 74 is connected to the inlet of the compressor 41, the first evaporator 44 and the second evaporator 12, and the fifth control valve 75 is connected to the condenser 42, the first throttling device 43 and the second throttling device 11.

[0140] By setting the fourth control valve 74 and the fifth control valve 75, the second throttling device 11 and the second evaporator 12 can be connected to the compressor 41 and condenser 42 in the first air conditioning unit 4, thereby forming a second air conditioning unit, without affecting the operation of the first air conditioning unit 4.

[0141] The refrigerant flow path in the first air conditioning unit 4 is as follows: compressor 41 → condenser 42 → fifth control valve 75 → first throttling device 43 → first evaporator 44 → fourth control valve 74 → compressor 41.

[0142] The refrigerant flow path in the second air conditioning unit is as follows: compressor 41 → condenser 42 → fifth control valve 75 → second throttling device 11 → second evaporator 12 → fourth control valve 74 → compressor 41.

[0143] The second evaporator 12 can be installed inside or adjacent to the cab 10. The air supply device 13 is installed adjacent to the second evaporator 12. The air supply device 13 can be installed inside or adjacent to the cab 10. The air supply device 13 can be a blower or other device with air supply capability.

[0144] In some embodiments, the thermal management system further includes a cab 10, a second heat exchanger 14, and an air supply device 13. The battery pack 1, the first liquid pump 3, and the second heat exchanger 14 are connected to form a fifth circulation loop 500 to transfer heat from the battery pack 1 to the second heat exchanger 14 via a circulation medium. The air supply device 13 is configured to deliver hot air around the second heat exchanger 14 into the cab 10.

[0145] In the above embodiment, by setting the second heat exchanger 14, the heat emitted by the battery pack 1 can be used to heat up the cab 10, realize the reuse of waste heat, save the energy specifically configured for heating the cab 10, and also save the energy for cooling the battery pack 1.

[0146] The second heat exchanger 14 can be installed inside the cab 10 or adjacent to the cab 10. The air supply device 13 is installed adjacent to the second heat exchanger 14.

[0147] After the circulating medium flows through the battery pack 1, its temperature rises. Then, the circulating medium reaches the second heat exchanger 14, which can increase the temperature of the air around the second heat exchanger 14. Under the action of the air supply device 13, the hot air can be sent into the cab 10 to heat the cab 10.

[0148] In some embodiments, the thermal management system further includes a first control valve 71 disposed in the first circulation loop 100, a sixth control valve 76 disposed in the first circulation loop 100, a second control valve 72 disposed in the second circulation loop 200, and a seventh control valve 77 disposed in the second circulation loop 200. The first control valve 71 is connected to the first liquid pump 3, the first evaporator 44, and the second control valve 72. The second control valve 72 is connected to the second liquid pump 53, the condenser 42, and the first control valve 71. The sixth control valve 76 is connected to the battery pack 1, the first evaporator 44, and the second heat exchanger 14. The seventh control valve 77 is connected to the second liquid pump 53, the first heat exchanger 52, and the second heat exchanger 14.

[0149] By setting the first control valve 71, the second control valve 72, the sixth control valve 76 and the seventh control valve 77, the battery pack 1 and the first liquid pump 3 can be connected to the second heat exchanger 14 to form a fifth circulation loop 500, thereby using the heat of the battery pack 1 to heat the cab 10, without affecting the use of other circulation loops such as the first circulation loop 100 and the second circulation loop 200.

[0150] When the heat from battery pack 1 is used to heat the cab 10, the flow path of the circulating medium in the fifth circulation loop 500 is as follows: battery pack 1 → first liquid pump 3 → first control valve 71 → second control valve 72 → second liquid pump 53 → seventh control valve 77 → second heat exchanger 14 → sixth control valve 76 → battery pack 1.

[0151] In some embodiments, the thermal management system further includes a cab 10, a second heat exchanger 14, an air supply device 13, a motor 8, and a second controller 9 for controlling the motor 8. The motor 8, the second controller 9, the second liquid pump 53, and the second heat exchanger 14 are connected to form a sixth circulation loop 600 to transfer the heat generated by the motor 8 and the second controller 9 to the second heat exchanger 14 through a circulation medium. The air supply device 13 is configured to deliver hot air around the second heat exchanger 14 into the cab 10.

[0152] In the above embodiment, by setting the second heat exchanger 14, the heat generated when the motor 8 and the second controller 9 are working can be used to heat up the cab 10, realize the reuse of waste heat, save the energy configured specifically for heating up the cab 10, and also save the energy for cooling down the motor 8 and the second controller 9.

[0153] After the circulating medium flows through the motor 8 and the second controller 9, its temperature rises. Then, the circulating medium reaches the second heat exchanger 14, which can increase the temperature of the air around the second heat exchanger 14. Under the action of the air supply device 13, the hot air can be sent into the cab 10 to heat the cab 10.

[0154] In some embodiments, the thermal management system further includes a second control valve 72 disposed in the second circulation loop 200, a third control valve 73 disposed in the second circulation loop 200, a seventh control valve 77 disposed in the second circulation loop 200, and an eighth control valve 78 disposed in the sixth circulation loop 600. The second control valve 72 is connected to the second liquid pump 53, the condenser 42, and the motor 8. The third control valve 73 is connected to the first heat exchanger 52, the condenser 42, the motor 8, and the eighth control valve 78. The seventh control valve 77 is connected to the second liquid pump 53, the first heat exchanger 52, and the second heat exchanger 14. The eighth control valve 78 is connected to the battery pack 1, the third control valve 73, and the second heat exchanger 14.

[0155] By setting the second control valve 72, the third control valve 73, the seventh control valve 77 and the eighth control valve 78, the motor 8 and the second controller 9 can be connected to the second liquid pump 53 and the second heat exchanger 14 to form the sixth circulation loop 600, thereby using the heat generated by the motor 8 and the second controller 9 to heat the cab 10, without affecting the use of other circulation loops such as the first circulation loop 100 and the second circulation loop 200.

[0156] When the heat from the motor 8 and the second controller 9 is used to heat the cab 10, the flow path of the circulating medium in the sixth circulation loop 600 is as follows: second controller 9 → motor 8 → second control valve 72 → second liquid pump 53 → seventh control valve 77 → second heat exchanger 14 → eighth control valve 78 → third control valve 73 → second controller 9.

[0157] In some embodiments, the thermal management system further includes a motor 8 and a second controller 9 for controlling the motor 8. The motor 8, the second controller 9, the battery pack 1, and the first liquid pump 3 are connected to form a seventh circulation loop 700 to transfer the heat generated by the motor 8 and the second controller 9 to the battery pack 1 through a circulation medium.

[0158] In the above embodiment, the motor 8, the second controller 9, the battery pack 1 and the first liquid pump 3 are connected to form a seventh circulation loop 700, which can use the heat generated by the motor 8 and the second controller 9 to heat the battery pack 1 and improve the working performance of the battery pack 1 in low-temperature environments.

[0159] In some embodiments, the thermal management system further includes a motor 8, a second controller 9 for controlling the motor 8, a first control valve 71 disposed in the first circulation loop 100, a sixth control valve 76 disposed in the first circulation loop 100, a second control valve 72 disposed in the second circulation loop 200, and a third control valve 73 disposed in the second circulation loop 200. The first control valve 71 is connected to the first liquid pump 3, the first evaporator 44, and the second control valve 72. The second control valve 72 is connected to the second liquid pump 53, the condenser 42, the first control valve 71, and the motor 8. The third control valve 73 is connected to the first heat exchanger 52, the condenser 42, the motor 8, and the sixth control valve 76. The sixth control valve 76 is connected to the battery pack 1, the first evaporator 44, and the third control valve 73.

[0160] By setting the first control valve 71, the second control valve 72, the third control valve 73 and the sixth control valve 76, the battery pack 1 and the first liquid pump 3 can be connected to the motor 8 and the second controller 9 to form a seventh circulation loop 700, without affecting the normal use of other circulation loops.

[0161] When the heat from the motor 8 and the second controller 9 is used to heat the battery pack 1, the flow path of the circulating medium in the seventh circulation loop 700 is as follows: battery pack 1 → first liquid pump 3 → first control valve 71 → second control valve 72 → motor 8 → second controller 9 → third control valve 73 → sixth control valve 76 → battery pack 1.

[0162] Based on the electric construction machinery thermal management system in the above embodiments, this disclosure provides an electric construction machinery including the above-described electric construction machinery thermal management system.

[0163] The positive technical effects of the thermal management system for electric construction machinery in the above embodiments are also applicable to electric construction machinery, and will not be repeated here.

[0164] like Figure 2 As shown, based on the electric construction machinery thermal management system in the above embodiments, this disclosure provides a control method for the electric construction machinery thermal management system, the control method including:

[0165] When the battery pack 1 is in charging mode and the temperature of the circulating medium flowing through the battery pack 1 is not less than the first preset value, the first liquid pump 3 is turned on to make the first circulation loop 100 in a flowing state.

[0166] Start all of the first air conditioning units 4 and heat dissipation units 5.

[0167] In the above embodiment, when the battery pack 1 is in charging mode and the temperature of the circulating medium flowing through the battery pack 1 is not less than the first preset value, the battery pack 1 generates a relatively large amount of heat and has a large demand for cooling capacity. At this time, the first liquid pump 3 is turned on, so that the first circulation loop 100 is in a flowing state. The circulating medium on the first circulation loop 100 can carry away the heat of the battery pack 1 when it flows through the battery pack 1, thereby achieving the effect of cooling the battery pack 1. At the same time, all the first air conditioning units 4 and heat dissipation units 5 are started. The first air conditioning units 4 can be used to cool the circulating medium on the first circulation loop 100, thereby allowing the circulating medium to carry away more heat from the battery pack 1. The heat dissipation units 5 can promptly remove the heat dissipation of the condenser 42 in the first air conditioning units 4, thereby improving the cooling efficiency of the first air conditioning units 4. Starting all the first air conditioning units 4 and heat dissipation units 5 can obtain the maximum possible cooling effect.

[0168] The value of the first preset value can be flexibly set according to actual needs.

[0169] In some embodiments, the first preset value can be 16℃~20℃, such as 16℃, 17℃, 18℃, 19℃ or 20℃.

[0170] In some embodiments, the control method includes:

[0171] When the battery pack 1 is in charging mode and the temperature of the circulating medium flowing through the battery pack 1 is less than the first preset value, the first liquid pump 3 is turned on to make the first circulation loop 100 flow.

[0172] Shut down all of the first air conditioning units 4 and heat dissipation units 5.

[0173] In the above embodiment, when the battery pack 1 is in the charging state and the temperature of the circulating medium flowing through the battery pack 1 is less than the first preset value, although the battery pack 1 will still generate heat, it has a certain cooling capacity because the temperature of the circulating medium is less than the first preset value. Therefore, the first liquid pump 3 is turned on at this time to make the first circulation loop 100 flow, and the circulating medium can be used to cool the battery pack 1. Meanwhile, turning off all the first air conditioning units 4 and heat dissipation units 5 can effectively save energy and reduce costs.

[0174] In some embodiments, the control method includes:

[0175] When the battery pack 1 is in driving condition and the highest temperature of each cell in the battery pack 1 is not less than the second preset value, the battery pack 1 has a large demand for cooling capacity. At this time, the first liquid pump 3 is turned on to make the first circulation loop 100 flow, and all the first air conditioning units 4 and heat dissipation units 5 are started to obtain the maximum possible cooling capacity.

[0176] The second preset value can be flexibly set according to actual needs.

[0177] In some embodiments, the second preset value can be 26℃~30℃, such as 26℃, 27℃, 28℃, 29℃ or 30℃.

[0178] Then, the ambient temperature T of battery pack 1 was measured;

[0179] When T≥T1, the temperature of battery pack 1 is still high. Keeping all the first air conditioning units 4 and heat dissipation units 5 in the open state can continue to provide maximum cooling capacity and ensure the charging safety of battery pack 1.

[0180] The formula for calculating T1 is:

[0181]

[0182] in, The highest temperature of the environment in which the electric construction machinery operates ( It is usually between 53℃ and 57℃, such as 53℃, 54℃, 55℃, 56℃ or 57℃. The maximum cooling capacity required for vehicle operation is given by k, which is the temperature coefficient of the cooling capacity of a single compressor.

[0183] The calculated value of T1 is usually between 25℃ and 27℃, such as 25℃, 25.5℃, 26℃, 26.5℃ or 27℃.

[0184] When T2≤T<T1, keep half of the first air conditioning units 4 in the open state and turn off the other half of the first air conditioning units 4, while keeping the heat dissipation group 5 in the open state; turning off half of the first air conditioning units 4 at this time can effectively save energy.

[0185] When the heat dissipation group 5 contains multiple air circulation devices 54, when T2≤T<T1, half of the air circulation devices 54 are kept in the open state, and the other half of the air circulation devices 54 are closed.

[0186] The formula for calculating T2 is:

[0187]

[0188] in, The maximum cooling capacity required for vehicle operation. The temperature of the circulating medium required for battery pack 1. The specific heat capacity of the circulating medium. The density of the circulating medium, The flow rate of the first loop is 100. The specific heat capacity of air. For the density of air, This refers to the external airflow of heat dissipation unit 5.

[0189] The calculated value of T1 is usually between 13℃ and 17℃, such as 13℃, 14℃, 15℃, 16℃ or 17℃.

[0190] When T < T2, all units of the first air conditioning unit 4 are shut down, while the heat dissipation unit 5 remains open. Shutting down all units of the first air conditioning unit 4 at this time minimizes energy consumption while maintaining the temperature of the circulating medium to meet cooling requirements.

[0191] In some embodiments, the control method includes:

[0192] When the battery pack 1 is in driving condition, the highest temperature of each cell in the battery pack 1 is less than the second preset value, and the difference between the highest temperature tmax and the lowest temperature tmin of each cell is greater than or equal to the third preset value, all the first air conditioning units 4 and heat dissipation units 5 are turned off, and the first liquid pump 3 is turned on to keep the first circulation loop 100 in a flowing state until the difference between the highest temperature tmax and the lowest temperature tmin of each cell is detected to be less than or equal to the fourth preset value, at which point the first liquid pump 3 is turned off.

[0193] In the above embodiment, when the battery pack 1 is in driving condition and the highest temperature of each cell in the battery pack 1 is less than the second preset value, the heat generation of the battery pack 1 is reduced. However, when the difference between the highest temperature tmax and the lowest temperature tmin of each cell is greater than or equal to the third preset value, it is still necessary to cool down the battery pack 1. At this time, the first circulation loop 100 is started, and the self-circulation with low consumption cost can be used to achieve the effect of cooling down the battery pack 1.

[0194] When the difference between the highest temperature tmax and the lowest temperature tmin of each cell is less than or equal to the fourth preset value, the battery pack 1 basically does not need to be cooled. At this time, the first liquid pump 3 can be turned off to stop providing cooling and avoid energy waste.

[0195] The value of the third preset value can be flexibly set according to actual needs.

[0196] In some embodiments, the third preset value can be 9°C to 11°C, such as 9°C, 9.5°C, 10°C, 10.5°C, or 11°C.

[0197] The fourth preset value can be flexibly set according to actual needs.

[0198] In some embodiments, the fourth preset value can be 5℃~7℃, such as 5℃, 5.5℃, 6℃, 6.5℃ or 7℃.

[0199] In some embodiments, the thermal management system further includes a driver's cab 10, a second heat exchanger 14, an air supply device 13, a motor 8, and a second controller 9 for controlling the motor 8. The battery pack 1, the first liquid pump 3, and the second heat exchanger 14 are connected to form a fifth circulation loop 500. The motor 8, the second controller 9, the second liquid pump 53, and the second heat exchanger 14 are connected to form a sixth circulation loop 600. The control method includes:

[0200] When battery pack 1 is in charging mode, the fifth circulation loop 500 is activated to use the residual heat of battery pack 1 to heat the cab 10.

[0201] When the battery pack 1 is in driving condition, the fifth circulation circuit 500 and the sixth circulation circuit 600 are activated, and the residual heat of the battery pack 1 and the motor 8 is used to heat the cab 10.

[0202] In the above embodiments, the heating of the cab 10 utilizes the waste heat from the battery pack 1 or the motor 8, which can effectively utilize waste heat and reduce costs.

[0203] The following is combined Figure 1 and Figure 2 The structure and operation of one embodiment of the thermal management system for electric construction machinery provided in this disclosure will be described:

[0204] like Figure 1 As shown, the thermal management system includes a battery pack 1, a first liquid storage tank 2, a first liquid pump 3, a first air conditioning unit 4, a heat dissipation unit 5, a first controller 6, a first control valve 71, a second control valve 72, a third control valve 73, a fourth control valve 74, a fifth control valve 75, a sixth control valve 76, a seventh control valve 77, an eighth control valve 78, a motor 8, a second controller 9, a driver's cab 10, a second throttling device 11, a second evaporator 12, an air supply device 13, and a second heat exchanger 14.

[0205] The first air conditioning unit 4 includes a compressor 41, a condenser 42, a first throttling device 43, and a first evaporator 44. The heat dissipation unit 5 includes a second liquid storage tank 51, a first heat exchanger 52, a second liquid pump 53, and an air circulation device 54. The motor 8 includes a first motor 81 and a second motor 82.

[0206] The first end of the pipe flowing through battery pack 1 is connected to the inlet of the first liquid pump 3, and the inlet and outlet of the first liquid storage tank 2 are connected to the connecting pipe between the first end of the pipe flowing through battery pack 1 and the inlet of the first liquid pump 3. The outlet of the first liquid pump 3 is connected to the second end of the pipe flowing through battery pack 1.

[0207] A first control valve 71 and a sixth control valve 76 are connected in series on the connecting pipe between the outlet of the first liquid pump 3 and the second end of the pipe flowing through the battery pack 1. Multiple first evaporators 44 are connected in parallel between the first control valve 71 and the sixth control valve 76.

[0208] The connection relationships within each first air conditioning unit 4 are as follows: the outlet of compressor 41 is connected to the inlet of condenser 42, the outlet of condenser 42 is connected to the inlet of first throttling device 43, the outlet of first throttling device 43 is connected to the inlet of first evaporator 44, and the outlet of first evaporator 44 is connected to the inlet of compressor 41.

[0209] The outlet of the second liquid pump 53 is connected to the inlet of the first heat exchanger 52, and the outlet of the first heat exchanger 52 is connected to the inlet of the second liquid pump 53. A seventh control valve 77 is connected to the connecting pipe between the outlet of the second liquid pump 53 and the inlet of the first heat exchanger 52. A third control valve 73 and a second control valve 72 are connected to the connecting pipe between the outlet of the first heat exchanger 52 and the inlet of the second liquid pump 53. Multiple condensers 42 are connected in parallel between the third control valve 73 and the second control valve 72. The inlet and outlet of the second liquid storage tank 51 are connected between the third control valve 73 and the second control valve 72. Two air circulation devices 54 are arranged along the length of the first heat exchanger 52.

[0210] The first motor 81, the second motor 82, and the second controller 9 are connected in series between the second control valve 72 and the third control valve 73, and the pipelines containing the first motor 81, the second motor 82, and the second controller 9 are different from the pipelines containing the multiple condensers 42.

[0211] The first controller 6 is signal-connected to multiple compressors 41 and multiple air circulation devices 54 respectively, so as to independently control the start and stop of the multiple compressors 41 and multiple air circulation devices 54. The first controller 6 can independently control the start and stop of one or more compressors 41, and can also independently control the start and stop of one or more air circulation devices 54.

[0212] The first control valve 71 is a three-way valve, and its three ports are respectively connected to the first liquid pump 3, the second control valve 72, and the first evaporator 44.

[0213] The second control valve 72 is a four-way valve, and its four ports are respectively connected to the condenser 42, the first control valve 71, the motor 8, and the second liquid pump 53.

[0214] The third control valve 73 is a four-way valve, and its four ports are respectively connected to the condenser 42, the second controller 9, the eighth control valve 78, and the first heat exchanger 52.

[0215] The fourth control valve 74 is a three-way valve, and its three ports are respectively connected to the second evaporator 12, the compressor 41 and the first evaporator 44.

[0216] The fifth control valve 75 is a three-way valve, and its three ports are respectively connected to the first throttling device 43, the condenser 42, and the second throttling device 11.

[0217] The sixth control valve 76 is a three-way valve, and its three ports are connected to the battery pack 1, the first evaporator 44 and the eighth control valve 78, respectively.

[0218] The seventh control valve 77 is a three-way valve, and its three ports are respectively connected to the second liquid pump 53, the second heat exchanger 14 and the first heat exchanger 52.

[0219] The eighth control valve 78 is a three-way valve, and its three ports are respectively connected to the sixth control valve 76, the second heat exchanger 14, and the third control valve 73.

[0220] The second throttling device 11 and the second evaporator 12 can be combined with the compressor 41 and condenser 42 of any one of the first air conditioning units 4 to form a second air conditioning unit. The second evaporator 12 and the air supply device 13 are both located in the cab 10. The air supply device 13 can blow cold air near the second evaporator 12 into the cab 10 to achieve the effect of cooling the cab 10.

[0221] A fourth control valve 74 is provided between the compressor 41 and the first evaporator 44, and a fifth control valve 75 is provided between the condenser 42 and the first throttling device 43. A second throttling device 11 is connected between the fifth control valve 75 and the second evaporator 12. The second evaporator 12 is connected between the second throttling device 11 and the fourth control valve 74.

[0222] One end of the second heat exchanger 14 is connected to the seventh control valve 77, which is connected in series between the second liquid pump 53 and the first heat exchanger 52. The other end of the second heat exchanger 14 is connected to the eighth control valve 78, which is connected in series between the third control valve 73 and the sixth control valve 76. The sixth control valve 76 is located between the battery pack 1 and the first evaporator 44.

[0223] The thermal management system in this embodiment includes at least the following seven circulation loops and two internal cold circulation loops:

[0224] First circulation loop 100: Battery pack 1 → First liquid pump 3 → First control valve 71 → First evaporator 44 → Sixth control valve 76 → Battery pack 1.

[0225] The function of the first circulation loop 100 is to cool the battery pack 1 using the circulating medium.

[0226] Second circulation loop 200: Second liquid pump 53 → Seventh control valve 77 → First heat exchanger 52 → Third control valve 73 → Condenser 42 → Second control valve 72 → Second liquid pump 53.

[0227] The function of the second circulation loop 200 includes using the heat dissipation group 5 to dissipate heat from the condenser 42.

[0228] Third circulation loop 300: Battery pack 1 → First liquid pump 3 → First control valve 71 → Second control valve 72 → Second liquid pump 53 → Seventh control valve 77 → First heat exchanger 52 → Third control valve 73 → Eighth control valve 78 → Sixth control valve 76 → Battery pack 1.

[0229] The function of the third circulation loop 300 includes using the heat dissipation group 5 to dissipate heat from the circulating medium on the first circulation loop 100.

[0230] Fourth circulation loop 400: Second liquid pump 53 → Seventh control valve 77 → First heat exchanger 52 → Third control valve 73 → Second controller 9 → First motor 81 → Second motor 82 → Second control valve 72 → Second liquid pump 53.

[0231] The function of the fourth loop 400 includes using the heat dissipation group 5 to dissipate heat from the first motor 81, the second motor 82, and the second controller 9.

[0232] Fifth circulation loop 500: Battery pack 1 → First liquid pump 3 → First control valve 71 → Second control valve 72 → Second liquid pump 53 → Seventh control valve 77 → Second heat exchanger 14 → Eighth control valve 78 → Sixth control valve 76 → Battery pack 1.

[0233] The function of the fifth circulation loop 500 includes using the heat generated by the battery pack 1 to heat the cab 10.

[0234] Sixth loop 600: Second controller 9 → First motor 81 → Second motor 82 → Second control valve 72 → Second liquid pump 53 → Seventh control valve 77 → Second heat exchanger 14 → Eighth control valve 78 → Third control valve 73 → Second controller 9.

[0235] The function of the sixth circulation loop 600 is to use the heat generated by the first motor 81, the second motor 82 and the second controller 9 to heat the cab 10.

[0236] Seventh loop 700: Battery pack 1 → First liquid pump 3 → First control valve 71 → Second control valve 72 → Second motor 82 → First motor 81 → Second controller 9 → Third control valve 73 → Eighth control valve 78 → Sixth control valve 76 → Battery pack 1.

[0237] The function of the seventh loop 700 is to use the heat generated by the first motor 81, the second motor 82 and the second controller 9 to heat the battery pack 1.

[0238] The refrigerant flow path in the first air conditioning unit 4 is as follows: compressor 41 → condenser 42 → fifth control valve 75 → first throttling device 43 → first evaporator 44 → fourth control valve 74 → compressor 41.

[0239] The function of the first air conditioning unit 4 includes reducing the temperature of the circulating medium in the first circulation loop 100.

[0240] The refrigerant flow path in the second air conditioning unit is as follows: compressor 41 → condenser 42 → fifth control valve 75 → second throttling device 11 → second evaporator 12 → fourth control valve 74 → compressor 41.

[0241] The function of the second air conditioning unit is to cool the driver's cab 10.

[0242] The thermal management system in this embodiment includes at least the following five operational requirements:

[0243] 1. Cooling of battery pack 1:

[0244] For megawatt-level super-fast charging conditions, the cooling capacity requirement is over 100kW. For the special condition where the cooling capacity of battery pack 1 in driving conditions is 1 / 3 of that in super-fast charging conditions, the cooling process of battery pack 1 includes: cooling during charging conditions, cooling during high-temperature driving conditions, and cooling during low-temperature driving conditions.

[0245] (1) Cooling during charging:

[0246] When the first controller 6 receives the charging signal and the temperature detector detects that the temperature of the circulating medium flowing through the battery pack 1 is greater than or equal to 18°C, the following control is executed:

[0247] a. Open the first liquid pump 3, the first control valve 71 and the sixth control valve 76 to start the first circulation loop 100. The circulation medium flows sequentially through the battery pack 1, the first liquid pump 3, the first control valve 71, multiple first evaporators 44, the sixth control valve 76, and then returns to the battery pack 1.

[0248] b. Turn on the two compressors 41, the fourth control valve 74 and the fifth control valve 75 to start the air conditioning refrigeration cycle. The two sets of first air conditioning units 4 operate in parallel to maximize the output of cooling capacity.

[0249] c. Open the second control valve 72, the second liquid pump 53, the seventh control valve 77, the air circulation device 54 and the third control valve 73 to start the second circulation loop 200. The circulating medium flows sequentially through the second liquid pump 53, the seventh control valve 77, the first heat exchanger 52, the third control valve 73, the condenser 42, the second control valve 72, and finally back to the second liquid pump 53.

[0250] (2) Cooling under high-temperature operating conditions:

[0251] At this time, the first circulation loop 100, the air conditioning cooling loop, and the second circulation loop 200 are all in the same charging condition cooling mode. However, based on the ambient temperature T, the control modes of the multiple first air conditioning units 4 are divided into two segments:

[0252] a. When T1≤T, both compressors 41 remain on, operate in the high-efficiency zone, and adjust their speed according to cooling demand and water temperature.

[0253] Among them, T1 (usually chosen as 27℃)

[0254]

[0255] This represents the maximum ambient temperature, typically taken as 55℃. K represents the maximum required cooling capacity under driving conditions; K is the temperature coefficient of the cooling capacity of a single compressor.

[0256] b. When T2≤T≤T1, the compressor 41 on the right is turned off, the compressor 41 on the left is kept running in the high-efficiency zone, one air circulation device 54 is turned off, the other air circulation device 54 is kept running in the high-efficiency zone and its speed is adjusted according to the cooling demand and water temperature.

[0257] Wherein, T2 (usually chosen as 15℃) is calculated according to the following formula:

[0258]

[0259] The maximum cooling capacity required for vehicle operation. The temperature of the circulating medium required for battery pack 1. The specific heat capacity of the circulating medium. The density of the circulating medium, The flow rate of the first loop is 100. The specific heat capacity of air. For the density of air, This refers to the external airflow of heat dissipation unit 5.

[0260] (3) Cooling under low-temperature operating conditions:

[0261] When T < T2, the following control is executed: all compressors 41 are shut down, the third circulation loop 300 is started, and the circulating medium flows sequentially through battery pack 1, first liquid pump 3, first control valve 71, second control valve 72, second liquid pump 53, seventh control valve 77, first heat exchanger 52, third control valve 73, eighth control valve 78, and sixth control valve 76, finally returning to battery pack 1. This process relies on the circulating medium to remove the heat generated by battery pack 1, eliminating the need to start the air conditioning cooling cycle, effectively reducing overall vehicle energy consumption and improving the reliability of the refrigeration unit.

[0262] 2. Cooling of motor 8:

[0263] Based on the vehicle control signals, including the inlet water temperature of the first motor 81, the second motor 82, and the second controller 9, the first controller 6 determines the cooling demand and opens the second liquid pump 53, the air circulation device 54, the first heat exchanger 52, the second control valve 72, the third control valve 73, and the seventh control valve 77. The circulating medium flows sequentially through the second liquid pump 53, the seventh control valve 77, the first heat exchanger 52, the third control valve 73, the second controller 9, the first motor 81, the second motor 82, and the second control valve 72, finally returning to the second liquid pump 53. The speeds of the two air circulation devices 54 are adjusted according to the cooling demand.

[0264] 3. Refrigeration in cab 10:

[0265] Based on the cooling demand of the cab 10, the compressor 41, air supply device 13, fourth control valve 74, and fifth control valve 75 on the left are opened. The refrigerant flows sequentially through the compressor 41, condenser 42, fifth control valve 75, second throttling device 11, second evaporator 12, and fourth control valve 74, finally returning to the compressor 41. The speed of the compressor 41 and air supply device 13 can be adjusted according to the cooling demand, and the opening degree of the fourth control valve 74 and fifth control valve 75 can also be adjusted.

[0266] 4. Heating of the cab 10:

[0267] During charging, the waste heat from battery pack 1 is mainly used to heat the cab 10. When the first controller 6 receives a heating request from the cab 10 (the temperature of the circulating medium usually needs to be ≥50℃ and the flow rate usually needs to be ≥15L / min), it opens the first liquid pump 3, the second liquid pump 53, the air supply device 13, the first control valve 71, the second control valve 72 and the seventh control valve 77. The circulating medium flows sequentially through battery pack 1, first liquid pump 3, first control valve 71, second control valve 72, second liquid pump 53, seventh control valve 77, second heat exchanger 14, eighth control valve 78 and sixth control valve 76, and finally returns to battery pack 1.

[0268] During driving, in addition to using the waste heat of battery pack 1, the waste heat of motor 8 and second controller 9 is also used to heat the cab 10. At this time, the third control valve 73 needs to be opened. The circulating medium flows through the second controller 9, the first motor 81, the second motor 82, the second control valve 72, the second liquid pump 53, the seventh control valve 77, the second heat exchanger 14, the eighth control valve 78, and the third control valve 73 in sequence, and finally returns to the second controller 9.

[0269] 5. Heating of battery pack 1:

[0270] Because electric construction machinery generates a great deal of heat during charging, low temperatures have a limited impact on charging speed. Therefore, heating of battery pack 1 is mainly targeted at ambient temperatures below [temperature range missing]. (Typically, the driving condition is taken at 5℃). At this time, the heating required by battery pack 1 uses the driving heat generated by motor 8 and second controller 9. When battery pack 1 has a heating requirement, the first liquid pump 3, first control valve 71, second control valve 72, third control valve 73, eighth control valve 78, and sixth control valve 76 are opened. The circulating medium flows sequentially through battery pack 1, first liquid pump 3, first control valve 71, second control valve 72, second motor 82, first motor 81, second controller 9, third control valve 73, eighth control valve 78, and sixth control valve 76, and finally returns to battery pack 1. According to the heating requirement of battery pack 1 and the total residual heat of motor 8 and second controller 9, the speed of the first liquid pump 3 and the opening of the second control valve 72 and third control valve 73 can be adjusted.

[0271] Through the description of several embodiments of the electric construction machinery thermal management system of this disclosure, it can be seen that the embodiments of the electric construction machinery thermal management system of this disclosure have at least one or more of the following advantages:

[0272] 1. High degree of integration: It organically integrates the thermal management of the battery pack, the thermal management system of the motor and the second controller, and the thermal management of the cab. The electronic components in the system are centrally controlled by the first controller, which ensures that the battery pack, motor and the second controller can operate efficiently and stably, while taking into account the comfort of the cab occupants and improving the overall efficiency of the vehicle's thermal management.

[0273] 2. The integrated heat sink design allows the cooling of the battery, condenser, motor and second controller to share the same heat sink, which can allocate heat dissipation requirements according to different operating conditions, effectively reducing the layout space, reducing the overall vehicle cost, and also providing a foundation for subsequent low power consumption control methods.

[0274] 3. The cooling of battery pack 1 adopts the form of multiple independent first air conditioning units connected in parallel. Multiple first evaporators in the first circulation loop and multiple condensers in the second circulation loop are all connected in parallel, which increases the cooling capacity and heat exchange, effectively increasing the reliability of the system; and according to the cooling capacity demand, the compressor can be operated in the high-efficiency range as much as possible, improving energy utilization efficiency.

[0275] 4. The condenser adopts a water-cooled condenser, which significantly improves its applicability in high dust environments and expands the scope of application of the equipment compared to air-cooled condensers.

[0276] 5. Differentiated control is implemented for different operating conditions, such as cooling of the battery pack during charging, cooling during high-temperature driving, and cooling during low-temperature driving, as well as specific control strategies for the cooling of the motor and second controller, the cooling and heating of the cab, and the heating of the power battery. These strategies can adjust the operating status of each component according to actual needs, effectively reducing the overall energy consumption of the vehicle and improving the reliability of components such as the air conditioning unit.

[0277] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0278] Those skilled in the art will understand that, in the methods described in the specific embodiments, the order in which the steps are written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic.

[0279] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure and not to limit them; although this disclosure has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this disclosure or equivalent substitutions can still be made to some technical features without departing from the principles of this disclosure, and such modifications and equivalent substitutions should all be covered within the scope of the technical solutions claimed in this disclosure.

Claims

1. A thermal management system for electric engineering machinery, characterized in that, include: The battery pack (1) is configured to provide driving force; The first liquid storage tank (2) is configured to store circulating media; A first liquid pump (3) is connected to the first liquid storage tank (2). The first liquid pump (3) and the battery pack (1) are connected to form a first circulation loop (100). The first liquid pump (3) is configured to drive the circulation medium to flow through the battery pack (1) so that the circulation medium and the battery pack (1) exchange heat. Multiple first air conditioning units (4) are connected in parallel. Each first air conditioning unit (4) includes a compressor (41), a condenser (42), a first throttling device (43), and a first evaporator (44). Refrigerant flows between the compressor (41), the condenser (42), the first throttling device (43), and the first evaporator (44) to form a refrigerant circulation loop. The first air conditioning unit (4) is configured to reduce the temperature of the circulating medium in the first circulation loop (100). The heat dissipation unit (5) is configured to dissipate heat from the condenser (42) in the first air conditioning unit (4) and / or reduce the temperature of the circulating medium flowing through the battery pack (1); and A first controller (6) is signal-connected to a plurality of first air conditioning units (4) and the heat dissipation unit (5). The first controller (6) is configured to control the start and stop of the plurality of first air conditioning units (4) and the start and stop of the heat dissipation unit (5) according to the temperature of the battery pack (1).

2. The thermal management system for electric engineering machinery according to claim 1, characterized in that, Multiple first evaporators (44) are connected in parallel to the first circulation loop (100), and the refrigerant in the first evaporator (44) exchanges heat with the circulating medium in the first circulation loop (100).

3. The thermal management system for electric engineering machinery according to claim 1, characterized in that, The heat dissipation assembly (5) includes: The second liquid storage tank (51) is configured to store circulating media; First heat exchanger (52); A second liquid pump (53) is connected to the second liquid storage tank (51). The second liquid pump (53) and the first heat exchanger (52) are connected to form a second circulation loop (200). A plurality of the condensers (42) are connected in parallel to the second circulation loop (200). An air circulation device (54) is configured to accelerate the heat exchange between the circulating medium in the first heat exchanger (52) and the outside air.

4. The thermal management system for electric engineering machinery according to claim 1, characterized in that, The heat dissipation assembly (5) includes: The second liquid storage tank (51) is configured to store circulating media; First heat exchanger (52); The second liquid pump (53) is connected to the second liquid storage tank (51), and the battery pack (1), the first liquid pump (3), the second liquid pump (53), and the first heat exchanger (52) are connected to form a third circulation loop (300); and An air circulation device (54) is configured to accelerate the heat exchange between the circulating medium in the first heat exchanger (52) and the outside air.

5. The thermal management system for electric engineering machinery according to claim 3 or 4, characterized in that, The heat dissipation assembly (5) includes a plurality of the air circulation devices (54), and the first controller (6) is configured to control the start and stop of the plurality of air circulation devices (54) according to the temperature of the battery pack (1).

6. The thermal management system for electric engineering machinery according to claim 4, characterized in that, The thermal management system further includes a first control valve (71) disposed in the first circulation loop (100) and a second control valve (72) disposed in the third circulation loop (300). The first control valve (71) is connected to the first liquid pump (3), the first evaporator (44) and the second control valve (72). The second control valve (72) is connected to the second liquid pump (53), the condenser (42) and the first control valve (71).

7. The thermal management system for electric engineering machinery according to claim 1, characterized in that, The thermal management system further includes a motor (8) and a second controller (9) for controlling the motor (8), and the heat dissipation group (5) is configured to reduce the temperature of the motor (8) and the second controller (9).

8. The thermal management system for electric engineering machinery according to claim 3, characterized in that, The thermal management system further includes a motor (8) and a second controller (9) for controlling the motor (8). The motor (8), the second controller (9), the second liquid pump (53) and the first heat exchanger (52) are connected to form a fourth circulation loop (400) to remove the heat of the motor (8) and the second controller (9) through the circulation medium flowing through the motor (8) and the second controller (9).

9. The thermal management system for electric engineering machinery according to claim 8, characterized in that, The thermal management system further includes a second control valve (72) and a third control valve (73) disposed in the second circulation loop (200). The second control valve (72) is connected to the second liquid pump (53), the condenser (42) and the motor (8), and the third control valve (73) is connected to the first heat exchanger (52), the condenser (42) and the motor (8).

10. The thermal management system for electric engineering machinery according to claim 1, characterized in that, The thermal management system also includes a cab (10), a second throttling device (11), a second evaporator (12), and an air supply device (13). The compressor (41), the condenser (42), the second throttling device (11), and the second evaporator (12) form a second air conditioning unit. The air supply device (13) is configured to blow cold air around the second evaporator (12) into the cab (10).

11. The thermal management system for electric engineering machinery according to claim 10, characterized in that, The thermal management system further includes a fourth control valve (74) and a fifth control valve (75). The fourth control valve (74) is connected to the inlet of the compressor (41), the first evaporator (44) and the second evaporator (12). The fifth control valve (75) is connected to the condenser (42), the first throttling device (43) and the second throttling device (11).

12. The thermal management system for electric engineering machinery according to claim 3, characterized in that, The thermal management system further includes a cab (10), a second heat exchanger (14), and an air supply device (13). The battery pack (1), the first liquid pump (3), and the second heat exchanger (14) are connected to form a fifth circulation loop (500) to transfer heat from the battery pack (1) to the second heat exchanger (14) through the circulation medium. The air supply device (13) is configured to deliver hot air around the second heat exchanger (14) into the cab (10).

13. The thermal management system for electric engineering machinery according to claim 12, characterized in that, The thermal management system further includes a first control valve (71) and a sixth control valve (76) disposed in the first circulation loop (100), and a second control valve (72) and a seventh control valve (77) disposed in the second circulation loop (200). The first control valve (71) is connected to the first liquid pump (3), the first evaporator (44) and the second control valve (72). The second control valve (72) is connected to the second liquid pump (53), the condenser (42) and the first control valve (71). The sixth control valve (76) is connected to the battery pack (1), the first evaporator (44) and the second heat exchanger (14). The seventh control valve (77) is connected to the second liquid pump (53), the first heat exchanger (52) and the second heat exchanger (14).

14. The thermal management system for electric engineering machinery according to claim 3 or 12, characterized in that, The thermal management system further includes a cab (10), a second heat exchanger (14), an air supply device (13), a motor (8), and a second controller (9) for controlling the motor (8). The motor (8), the second controller (9), the second liquid pump (53), and the second heat exchanger (14) are connected to form a sixth circulation loop (600) to transfer the heat generated by the motor (8) and the second controller (9) to the second heat exchanger (14) through the circulation medium. The air supply device (13) is configured to deliver hot air around the second heat exchanger (14) into the cab (10).

15. The thermal management system for electric engineering machinery according to claim 14, characterized in that, The thermal management system further includes a second control valve (72), a third control valve (73), and a seventh control valve (77) disposed in the second circulation loop (200) and an eighth control valve (78) disposed in the sixth circulation loop (600). The second control valve (72) is connected to the second liquid pump (53), the condenser (42), and the motor (8). The third control valve (73) is connected to the first heat exchanger (52), the condenser (42), the motor (8), and the eighth control valve (78). The seventh control valve (77) is connected to the second liquid pump (53), the first heat exchanger (52), and the second heat exchanger (14). The eighth control valve (78) is connected to the battery pack (1), the third control valve (73), and the second heat exchanger (14).

16. The thermal management system for electric engineering machinery according to claim 1, characterized in that, The thermal management system further includes a motor (8) and a second controller (9) for controlling the motor (8). The motor (8), the second controller (9), the battery pack (1) and the first liquid pump (3) are connected to form a seventh circulation loop (700) to transfer the heat generated by the motor (8) and the second controller (9) to the battery pack (1) through the circulation medium.

17. The thermal management system for electric engineering machinery according to claim 3, characterized in that, The thermal management system further includes a motor (8), a second controller (9) for controlling the motor (8), a first control valve (71) and a sixth control valve (76) disposed in the first circulation loop (100), and a second control valve (72) and a third control valve (73) disposed in the second circulation loop (200). The first control valve (71) is connected to the first liquid pump (3), the first evaporator (44) and the second control valve (72). The second control valve (72) is connected to the second liquid pump (53), the condenser (42), the first control valve (71) and the motor (8). The third control valve (73) is connected to the first heat exchanger (52), the condenser (42), the motor (8) and the sixth control valve (76). The sixth control valve (76) is connected to the battery pack (1), the first evaporator (44) and the third control valve (73).

18. An electric engineering machine, characterized in that, Including the electric engineering machinery thermal management system as described in any one of claims 1 to 17.

19. A control method for an electric engineering machinery thermal management system as described in any one of claims 1 to 17, characterized in that, include: When the battery pack (1) is in charging condition and the temperature of the circulating medium flowing through the battery pack (1) is greater than or equal to a first preset value, the first liquid pump (3) is turned on to make the first circulation loop (100) flow. Start all of the first air conditioning units (4) and the heat dissipation units (5).

20. The control method according to claim 19, characterized in that, The control method includes: When the battery pack (1) is in charging mode and the temperature of the circulating medium flowing through the battery pack (1) is less than a first preset value, the first liquid pump (3) is turned on to make the first circulation loop (100) flow. Shut down all of the first air conditioning units (4) and the heat dissipation units (5).

21. The control method according to claim 19, characterized in that, The control method includes: When the battery pack (1) is in driving condition and the highest temperature of each cell in the battery pack (1) is greater than or equal to the second preset value, the first liquid pump (3) is turned on to make the first circulation loop (100) flow, and all the first air conditioning units (4) and the heat dissipation units (5) are started. At the same time, the ambient temperature T of the battery pack (1) is detected. When T≥T1, keep all the first air conditioning units (4) and the heat dissipation units (5) in the open state; The formula for calculating T1 is: in, This refers to the highest temperature of the environment in which the electric construction machinery operates. The maximum cooling capacity required for the driving conditions is given by k, where k is the temperature coefficient of the cooling capacity of a single compressor (41). When T2≤T<T1, half of the first air conditioning units (4) are kept in the open state, the other half of the first air conditioning units (4) are turned off, and the heat dissipation group (5) is kept in the open state. The formula for calculating T2 is: in, The maximum cooling capacity required for the aforementioned driving conditions. The temperature of the circulating medium required by the battery pack (1), The specific heat capacity of the circulating medium. The density of the circulating medium, The flow rate of the first loop (100) The specific heat capacity of air. For the density of air, The external airflow of the heat dissipation assembly (5); When T < T2, all of the first air conditioning units (4) are turned off, while the heat dissipation unit (5) is kept in the open state.

22. The control method according to claim 19, characterized in that, The control method includes: When the battery pack (1) is in driving condition, and the highest temperature of each cell in the battery pack (1) is less than the second preset value, and the difference between the highest temperature tmax and the lowest temperature tmin of each cell is greater than or equal to the third preset value, all the first air conditioning units (4) and the heat dissipation units (5) are turned off, and the first liquid pump (3) is turned on to make the first circulation loop (100) flow until the difference between the highest temperature tmax and the lowest temperature tmin of each cell is detected to be less than or equal to the fourth preset value, and then the first liquid pump (3) is turned off.

23. The control method according to claim 19, characterized in that, The thermal management system further includes a driver's cab (10), a second heat exchanger (14), an air supply device (13), a motor (8), and a second controller (9) for controlling the motor (8). The battery pack (1), the first liquid pump (3), and the second heat exchanger (14) are connected to form a fifth circulation loop (500), and the motor (8), the second controller (9), the second liquid pump (53), and the second heat exchanger (14) are connected to form a sixth circulation loop (600). The control method includes: When the battery pack (1) is in charging mode, the fifth circulation loop (500) is activated to heat the cab (10) using the residual heat of the battery pack (1); When the battery pack (1) is in driving condition, the fifth circulation loop (500) and the sixth circulation loop (600) are started, and the residual heat of the battery pack (1) and the motor (8) is used to heat the cab (10).

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