Integrated heat pump heat management system of electric forklift

Abstract

The invention discloses an electric forklift integrated heat pump heat management system which comprises a refrigerant loop and a cooling liquid loop, the refrigerant loop comprises a compressor, a four-way reversing valve, a cabin external heat exchanger, a one-way valve, a capillary tube, a first expansion valve, a cabin internal heat exchanger, a second expansion valve, a heat exchanger and a gas-liquid separator; the cooling liquid loop comprises a heat exchanger, a first water pump, a battery liquid cooling plate, a PTC heater, a radiator, a second water pump, a traction motor water jacket, a traction motor electric control water jacket, a main pump motor water jacket, a main pump motor electric control water jacket, an auxiliary pump motor water jacket and an auxiliary pump motor electric control water jacket. The integrated heat pump heat management system is adopted, the system integration degree is improved, and the winter endurance is improved by improving the winter heating energy efficiency; under different working conditions, through switching of multiple thermal management modes, a simultaneous thermal management function of a cabin, a battery, a motor and motor electric control is realized.

Description

Technical Field

[0001] The invention belongs to the field of thermal management of electric forklifts, and in particular relates to an integrated heat pump thermal management system for electric forklifts. Background Art

[0002] With the rapid development of new energy technology, the electric forklift industry has also gradually developed. The power source of electric forklifts is batteries. In order to improve battery safety and service life, the battery temperature needs to be controlled.

[0003] In addition to the battery, the forklift's cab, motor and motor electronic control all need a thermal management system for temperature control. At present, electric forklift thermal management systems are mostly independent of each other. Multiple systems will lead to complex structure and performance redundancy, which is not conducive to giving full play to the performance of the system and increases cost and additional mass.

[0004] Similar to electric vehicles, low temperatures in winter have a significant impact on the range of electric forklifts. This is mainly because most electric forklifts only use PTC heaters to heat the cabin and preheat the battery, and the COP of the PTC heater is <1, which means that a lot of electricity is needed for heating in winter. Although electric forklifts do not have the engine waste heat of fuel vehicles to use, the battery and motor components have high power when the forklift itself is working, and the corresponding heat generation power is also high. If this part of the heat is used reasonably to heat the cockpit, it can also reduce energy consumption and help improve the range of electric forklifts in winter. In addition, since the COP>1 of the heat pump air conditioning system, it is often used to replace the PTC heater to solve the problem of low heating efficiency of the thermal management system in winter. Summary of the invention

[0005] The purpose of the present invention is to overcome the above problems existing in the prior art, provide an integrated heat pump thermal management system for electric forklifts, adopt an integrated heat pump thermal management system to improve system integration, and improve winter endurance by improving winter heating efficiency.

[0006] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0007] The electric forklift integrated heat pump thermal management system includes a refrigerant circuit and a coolant circuit, wherein:

[0008] A refrigerant circuit, including a compressor, a four-way reversing valve, a cabin external heat exchanger, a one-way valve, a capillary tube, a first expansion valve, a cabin internal heat exchanger, a second expansion valve, a heat exchanger, and a gas-liquid separator;

[0009] The coolant circuit includes a heat exchanger, a first water pump, a battery liquid cooling plate, a PTC heater, a radiator, a second water pump, a traction motor water jacket, a traction motor electronic control water jacket, a main pump motor water jacket, a main pump motor electronic control water jacket, an auxiliary pump motor water jacket, and an auxiliary pump motor electronic control water jacket.

[0010] Further, the refrigerant circuit further includes a first three-way pipe, a second three-way pipe, a third three-way pipe, a fourth three-way pipe, a first solenoid valve, and a fifth three-way pipe, wherein:

[0011] The compressor exhaust port is connected to the port A of the four-way reversing valve, and the compressor air inlet is connected to the outlet of the gas-liquid separator;

[0012] The B port of the four-way reversing valve is connected to one end of the heat exchanger outside the cabin, the C port of the four-way reversing valve is connected to the A port of the first three-way pipe, and the D port of the four-way reversing valve is connected to the A port of the second three-way pipe;

[0013] The port B of the first three-way pipe is connected to the port C of the first three-way reversing valve, and the port C of the first three-way pipe is connected to the inlet of the gas-liquid separator;

[0014] The port B of the second three-way pipe is connected to one end of the heat exchanger inside the cabin, and the port C of the second three-way pipe is connected to the port B of the first three-way reversing valve;

[0015] The other end of the cabin external heat exchanger is connected to the A port of the third three-way pipe, the B port of the third three-way pipe is connected to the inlet of the one-way valve, the outlet of the one-way valve is connected to the A port of the fourth three-way pipe, and the C port of the third three-way pipe is connected to the C port of the fourth three-way pipe via a refrigerant pipe provided with a capillary tube;

[0016] The B port of the fourth three-way pipe is connected to one end of the first solenoid valve, and the other end of the first solenoid valve is connected to the A port of the fifth three-way pipe;

[0017] The port B of the fifth three-way pipe is connected to one end of the second expansion valve, the port C of the fifth three-way pipe is connected to one end of the first expansion valve, and the other end of the first expansion valve is connected to the other end of the heat exchanger inside the cabin;

[0018] The other end of the second expansion valve is connected to one end of the heat exchanger on the refrigerant side, and the other end of the heat exchanger on the refrigerant side is connected to the A port of the first three-way reversing valve.

[0019] Further, the coolant circuit also includes a sixth three-way pipe, a second three-way reversing valve, a third three-way reversing valve, a seventh three-way pipe, an eighth three-way pipe, a ninth three-way pipe, a second solenoid valve, a third solenoid valve, a fourth solenoid valve, a fifth solenoid valve, a thirteenth three-way pipe, an eleventh three-way pipe, a twelfth three-way pipe, and a thirteenth three-way pipe, wherein:

[0020] One end of the heat exchanger coolant side is connected to the C port of the sixth three-way pipe, and the other end of the heat exchanger coolant side is connected to the C port of the second three-way reversing valve;

[0021] The B port of the sixth three-way pipe is connected to the B port of the second three-way reversing valve, and the A port of the sixth three-way pipe is connected to the A port of the thirteenth pipe through the coolant pipeline of the battery liquid cooling plate and the PTC heater connected in series in sequence;

[0022] The port A of the first water pump is connected to the port A of the second three-way reversing valve, and the port B of the first water pump is connected to the port A of the third three-way reversing valve;

[0023] The C port of the third three-way reversing valve is directly connected to the C port of the thirteenth three-way pipe via a coolant pipe, and the B port of the third three-way reversing valve is connected to the A port of the seventh three-way pipe;

[0024] The port A of the eighth three-way pipe is connected to the port B of the seventh three-way pipe, and the port B of the eighth three-way pipe is connected to the port A of the ninth three-way pipe;

[0025] The port B of the thirteenth through-pipe is connected to the port A of the eleventh three-way pipe;

[0026] The port A of the twelfth tee is connected to the port B of the eleventh tee, and the port B of the twelfth tee is connected to the port A of the thirteenth tee;

[0027] The outlet of the second water pump is connected to the C port of the seventh three-way pipe, and the inlet of the second water pump is connected to the C port of the eleventh three-way pipe through a coolant pipeline which is connected in series with a radiator and a fifth solenoid valve in sequence;

[0028] The C port of the eighth tee is connected to the C port of the twelfth tee through a coolant pipeline on which a second solenoid valve, a traction motor electronic control water jacket, and a traction motor water jacket are sequentially connected;

[0029] The C port of the ninth tee is connected to the C port of the thirteenth tee through a coolant pipeline on which a third solenoid valve, a main pump motor electric control water jacket and a main pump motor water jacket are sequentially connected;

[0030] The B port of the ninth three-way pipe is connected to the B port of the thirteenth three-way pipe through a coolant pipeline on which the fourth solenoid valve, the auxiliary pump motor electronic control water jacket and the auxiliary pump motor water jacket are sequentially connected.

[0031] Further, in the high-temperature cooling mode: the compressor is started, the first water pump is started and works with port A as the outlet, the second water pump is started, the PTC heater is turned off, the port A of the four-way reversing valve is controlled to be connected to the port B, the port C and the port D are controlled to be connected, the port A of the first three-way reversing valve is controlled to be connected to the port C, the port A of the second three-way reversing valve is controlled to be connected to the port C, the port A of the third three-way reversing valve is controlled to be connected to the port B, and the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve and the fifth solenoid valve are controlled to be opened;

[0032] The compressor discharges high-temperature and high-pressure refrigerant vapor from the exhaust port, enters the cabin external heat exchanger through the four-way reversing valve to release heat and condense, and then enters the fifth three-way pipe to be divided into two paths: one path enters the cabin internal heat exchanger after being throttled by the first expansion valve, absorbs heat from the cabin and evaporates, thereby cooling the cockpit, and finally enters the first three-way pipe through the four-way reversing valve; the other path enters the heat exchanger after being throttled by the second expansion valve, absorbs heat from the coolant and evaporates, thereby cooling the coolant, and finally enters the first three-way pipe through the first three-way reversing valve; the two refrigerants enter the gas-liquid separator after merging in the first three-way pipe, and the refrigerant vapor separated by the gas-liquid separator enters the compressor suction port, completing the refrigerant cycle;

[0033] The coolant that has been cooled by the radiator and dissipated heat to the outside is pumped into the seventh three-way pipe by the second water pump and then divided into two paths: one path passes through the third three-way reversing valve, is further pressurized by the first water pump, enters the heat exchanger through the second three-way reversing valve, releases heat to the refrigerant and is further cooled, then enters the battery liquid cooling plate to absorb heat, thereby cooling the battery, and finally enters the eleventh three-way pipe; the other path passes through the eighth three-way pipe and the ninth three-way pipe and is further divided into three paths. The first path enters the traction motor electronic control water jacket and the traction motor water jacket in turn, and absorbs heat therefrom, thereby The traction motor electronic control and traction motor are cooled. The second route enters the main pump motor electronic control water jacket and the main pump motor water jacket in turn, and absorbs heat therefrom, thereby cooling the main pump motor electronic control and the main pump motor. The third route enters the auxiliary pump motor electronic control water jacket and the auxiliary pump motor water jacket in turn, and absorbs heat therefrom, thereby cooling the auxiliary pump motor electronic control and the auxiliary pump motor. Finally, the three routes of coolant are combined into one route through the twelfth tee and the thirteenth tee, and enter the eleventh tee; after the two routes of coolant are combined at the eleventh tee, they enter the radiator to complete the coolant circulation.

[0034] Furthermore, in the high-temperature cooling mode: if the cabin does not need to be cooled, close the first expansion valve, so that the refrigeration circuit can only cool the coolant; if the outside temperature is low, or the battery heat load is not high, close the second expansion valve, control the A port and B port of the second three-way reversing valve to be connected, so that the coolant can be cooled only by the radiator; if the temperature of the traction motor electronic control and the traction motor is lower than its target temperature, close the second solenoid valve on the branch where its water jacket is located, if the main pump motor electronic control, the main pump motor or the auxiliary pump motor electronic control, the auxiliary pump motor does not need to be cooled, the operation is the same.

[0035] Furthermore, in the low temperature heat pump heating mode:

[0036] The compressor starts, the first water pump starts and works with port B as the outlet, the second water pump is turned off, the PTC heater is turned on, the A port of the four-way reversing valve is controlled to be connected to the D port, the B port is controlled to be connected to the C port, the A port of the first three-way reversing valve is controlled to be connected to the B port, the A port of the second three-way reversing valve is controlled to be connected to the C port, the A port of the third three-way reversing valve is controlled to be connected to the C port, the first solenoid valve is controlled to be opened, and the second solenoid valve, the third solenoid valve, the fourth solenoid valve and the fifth solenoid valve are controlled to be closed;

[0037] The compressor discharges high-temperature and high-pressure refrigerant vapor from the exhaust port, and after entering the second three-way pipe through the four-way reversing valve, it is divided into two paths: one path enters the heat exchanger inside the cabin to release heat and condense, thereby heating the cabin cockpit, and then throttles through the first expansion valve, and finally enters the fifth three-way pipe; the other path enters the heat exchanger after passing through the first three-way reversing valve, releases heat to the coolant and condenses, and then throttles through the second expansion valve, and finally enters the fifth three-way pipe; after the two refrigerant paths merge at the fifth three-way pipe, they enter the capillary tube through the fourth three-way pipe for further throttling, and then enter the heat exchanger outside the cabin to absorb heat and evaporate, and finally enter the gas-liquid separator through the four-way reversing valve and the first three-way pipe. The refrigerant vapor separated by the gas-liquid separator enters the compressor suction port, completing the refrigerant cycle;

[0038] The coolant after heating the battery by the battery liquid cooling plate enters the heat exchanger, and after being heated by the refrigerant, enters the first water pump through the second three-way reversing valve, and then is pumped into the PTC heater through the third three-way reversing valve and the thirteenth pipe for further heating, and finally enters the battery liquid cooling plate to complete the coolant circulation.

[0039] Furthermore, in the low-temperature heat pump heating mode: if the cabin does not need to be heated, closing the first expansion valve can enable the heat pump cycle to heat only the coolant; if the battery does not need to be heated, closing the second expansion valve can enable the heat pump cycle to heat only the cockpit.

[0040] Furthermore, in the low temperature waste heat recovery mode:

[0041] The compressor starts, the first water pump starts and works with port B as the outlet, the second water pump is turned off, the PTC heater is turned on, the A port of the four-way reversing valve is controlled to be connected to the D port, the B port is controlled to be connected to the C port, the A port of the first three-way reversing valve is controlled to be connected to the C port, the A port of the second three-way reversing valve is controlled to be connected to the C port, the A port of the third three-way reversing valve is controlled to be connected to the B port, the first solenoid valve and the fifth solenoid valve are controlled to be closed, and the second solenoid valve, the third solenoid valve and the fourth solenoid valve are controlled to be opened;

[0042] The compressor discharges high-temperature and high-pressure refrigerant vapor from the exhaust port, enters the heat exchanger inside the cabin through the four-way reversing valve to release heat and condense, thereby heating the cabin, then enters the second expansion valve through the first expansion valve and the fifth three-way valve to throttle, then enters the heat exchanger to evaporate and absorb heat from the coolant, and finally enters the gas-liquid separator through the first three-way reversing valve and the first three-way pipe. The refrigerant vapor separated by the gas-liquid separator enters the compressor suction port, completing the refrigerant cycle;

[0043] The coolant that has been cooled by releasing heat to the refrigerant through the heat exchanger is pumped out by the first water pump through the second three-way reversing valve, and then passes through the third three-way reversing valve and the seventh three-way pipe, enters the ninth three-way pipe and the thirteenth three-way pipe and is divided into three paths; the first path enters the traction motor electronic control water jacket and the traction motor water jacket in turn and absorbs heat therefrom, the second path enters the main pump motor electronic control water jacket and the main pump motor water jacket in turn and absorbs heat therefrom, the third path enters the auxiliary pump motor electronic control water jacket and the auxiliary pump motor water jacket in turn and absorbs heat therefrom, and then the three paths of coolant are combined into one path through the twelfth three-way pipe and the thirteenth three-way pipe, enter the PTC heater for further heating, and then enter the battery cooling plate to cool or heat the battery, and finally enter the heat exchanger to complete the coolant circulation.

[0044] Furthermore, in the low-temperature waste heat recovery mode: if the outlet coolant temperature of the traction motor electronic control water jacket and the branch where the traction motor water jacket is located is lower than the inlet temperature, the second solenoid valve on the branch is closed to prevent heat loss; if the outlet coolant temperature of the main pump motor electronic control water jacket, the main pump motor water jacket or the auxiliary pump motor electronic control water jacket, and the auxiliary pump motor water jacket is lower than the inlet temperature, the operation is similar; if there is no waste heat available in the three branches where the motor electronic control and the motor water jacket are located, the A port of the third three-way reversing valve is controlled to be connected to the C port, and the battery waste heat and the PTC heater are used for heating; if the battery temperature If the temperature is high, the first water pump is controlled to pump out the coolant from port A, so that the coolant, which has been cooled by releasing heat to the refrigerant through the heat exchanger, enters the battery liquid cooling plate to cool the battery; if the power of the battery, the motor electronic control and the motor are all high, and the waste heat is sufficient, resulting in high temperatures of the battery, the motor electronic control and the motor, the port A of the third three-way reversing valve is controlled to be connected to the port C, the fifth solenoid valve is opened, and the second water pump is started, so that the coolant circulation is changed from a large circulation to two small circulations, one circulation uses the waste heat of the battery to heat the cabin, and the other circulation uses the radiator to heat the outside world to cool the motor electronic control and the motor.

[0045] The beneficial effects of the present invention are:

[0046] The present invention realizes the simultaneous thermal management function of the cabin, battery, motor and motor electronic control under different working conditions by switching between multiple thermal management modes. By rationally using controllable components such as four-way reversing valves, three-way reversing valves and solenoid valves to control the fluid flow path in the pipeline, not only a variety of thermal management function modes are realized, but also independent thermal management of each managed object can be achieved, thereby improving the flexibility of the system and thus improving the ability to cope with complex working conditions. In winter, the waste heat generated by the battery, motor and motor electronic control is used to heat the cockpit, and the heat pump system and PTC heater are used to heat the battery at the same time, which can not only realize rapid preheating of the battery, but also improve the energy efficiency of the thermal management system in the process, thereby avoiding the problem of severely shortened battery life caused by using only PTC heaters for heating in winter. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0048] Figure 1 It is a schematic diagram of the structure of the integrated heat pump thermal management system for an electric forklift in the present invention.

[0049] Figure 2 This is a schematic diagram of the positions of ports A, B, C, and D of the four-way reversing valve in the integrated heat pump thermal management system for an electric forklift of the present invention.

[0050] Figure 3 This is a schematic diagram of the positions of ports A, B, and C of the three-way pipe in the integrated heat pump thermal management system for an electric forklift of the present invention.

[0051] Figure 4 This is a schematic diagram of the positions of ports A, B, and C of the three-way reversing valve in the integrated heat pump thermal management system for an electric forklift of the present invention.

[0052] Figure 5 This is a schematic diagram of the positions of the A and B ports of the first water pump in the integrated heat pump thermal management system for an electric forklift of the present invention.

[0053] Figure 6 Schematic diagram of high temperature cooling mode in the integrated heat pump thermal management system for electric forklifts of the present invention.

[0054] Figure 7 It is a schematic diagram of the low-temperature heat pump heating mode in the integrated heat pump thermal management system for electric forklifts of the present invention.

[0055] Figure 8 It is a schematic diagram of low-temperature waste heat recovery in the integrated heat pump thermal management system for electric forklifts of the present invention.

[0056] The numbers in the figure are: 1-compressor, 2-four-way reversing valve, 3-cabin external heat exchanger, 4-check valve, 5-capillary tube, 6-first expansion valve, 7-cabin internal heat exchanger, 8-second expansion valve, 9-heat exchanger, 10-gas-liquid separator, 11-first water pump, 12-battery liquid cooling plate, 13-PTC heater, 14-radiator, 15-second water pump, 16-traction motor water jacket, 17-traction motor electronic control water jacket, 18-main pump motor water jacket, 19-main pump motor electronic control water jacket, 20-auxiliary pump motor water jacket, 21-auxiliary pump motor electronic control water jacket, 110-first three-way pipe, 111 -Second three-way pipe, 112-third three-way pipe, 113-fourth three-way pipe, 114-first solenoid valve, 115-fifth three-way pipe, 116-first three-way reversing valve, 117-sixth three-way pipe, 118-second three-way reversing valve, 119-third three-way reversing valve, 120-seventh three-way pipe, 121-eighth three-way pipe, 122-ninth three-way pipe, 123-second solenoid valve, 124-third solenoid valve, 125-fourth solenoid valve, 126-fifth solenoid valve, 127-thirteenth pipe, 128-eleventh three-way pipe, 129-twelfth three-way pipe, 130-thirteenth three-way pipe. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the present invention provides an integrated heat pump thermal management system for electric forklifts, including a refrigerant circuit and a coolant circuit. The refrigerant circuit is mainly composed of a compressor 1, a four-way reversing valve 2, a cabin external heat exchanger 3, a one-way valve 4, a capillary 5, a first expansion valve 6, a cabin internal heat exchanger 7, a second expansion valve 8, a heat exchanger 9, and a gas-liquid separator 10. The coolant circuit is mainly composed of a heat exchanger 9, a first water pump 11, a battery liquid cold plate 12, a PTC heater 13, a radiator 14, a second water pump 15, a traction motor water jacket 16, a traction motor electronic control water jacket 17, a main pump motor water jacket 18, a main pump motor electronic control water jacket 19, an auxiliary pump motor water jacket 20, and an auxiliary pump motor electronic control water jacket 21.

[0059] Refrigerant circuit piping connections Figure 1As shown by the solid line. The exhaust port of the compressor 1 is connected to the A port of the four-way reversing valve 2, and the air inlet of the compressor 1 is connected to the outlet of the gas-liquid separator 10. The B port of the four-way reversing valve 2 is connected to one end of the heat exchanger 3 outside the cabin, the C port of the four-way reversing valve 2 is connected to the A port of the first three-way pipe 110, and the D port of the four-way reversing valve 2 is connected to the A port of the second three-way pipe 111. The B port of the first three-way pipe 110 is connected to the C port of the first three-way reversing valve 116, and the C port of the first three-way pipe 110 is connected to the inlet of the gas-liquid separator 10. The B port of the second three-way pipe 111 is connected to one end of the heat exchanger 7 inside the cabin, and the C port of the second three-way pipe 111 is connected to the B port of the first three-way reversing valve 116. The other end of the cabin external heat exchanger 3 is connected to the A port of the third three-way pipe 112, the B port of the third three-way pipe 112 is connected to the inlet of the one-way valve 4, the outlet of the one-way valve 4 is connected to the A port of the fourth three-way pipe 113, and the C port of the third three-way pipe 112 is connected to the C port of the fourth three-way pipe 113 through the refrigerant pipeline provided with the capillary tube 5. The B port of the fourth three-way pipe 113 is connected to one end of the first electromagnetic valve 114, and the other end of the first electromagnetic valve 114 is connected to the A port of the fifth three-way pipe 115. The B port of the fifth three-way pipe 115 is connected to one end of the second expansion valve 8, the C port of the fifth three-way pipe 115 is connected to one end of the first expansion valve 6, and the other end of the first expansion valve 6 is connected to the other end of the cabin internal heat exchanger 7. The other end of the second expansion valve 8 is connected to one end of the heat exchanger 9 on the refrigerant side, and the other end of the heat exchanger 9 on the refrigerant side is connected to the A port of the first three-way reversing valve.

[0060] Coolant circuit pipe connections Figure 1As shown by the dashed line in the middle. One end of the heat exchanger 9 on the coolant side is connected to the C port of the sixth three-way pipe 117, and the other end of the heat exchanger 9 on the coolant side is connected to the C port of the second three-way reversing valve 118. The B port of the sixth three-way pipe 117 is connected to the B port of the second three-way reversing valve 118, and the A port of the sixth three-way pipe 117 is connected to the A port of the thirteenth pipe 127, and the coolant pipeline of the battery liquid cooling plate 12 and the PTC heater 13 are connected in series thereon in sequence. The A port of the first water pump 11 is connected to the A port of the second three-way reversing valve 118, and the B port of the first water pump 11 is connected to the A port of the third three-way reversing valve 119. The C port of the third three-way reversing valve 119 is directly connected to the C port of the thirteenth pipe 127 through the coolant pipeline, and the B port of the third three-way reversing valve 119 is connected to the A port of the seventh three-way pipe 120. The A port of the eighth three-way pipe 121 is connected to the B port of the seventh three-way pipe 120, and the B port of the eighth three-way pipe 121 is connected to the A port of the ninth three-way pipe 122. The B port of the thirteenth three-way pipe 127 is connected to the A port of the eleventh three-way pipe 128. The A port of the twelfth three-way pipe 129 is connected to the B port of the eleventh three-way pipe 128, and the B port of the twelfth three-way pipe 129 is connected to the A port of the thirteenth three-way pipe 130. The outlet of the second water pump 15 is connected to the C port of the seventh three-way pipe 120, and the inlet of the second water pump 15 is connected to the C port of the eleventh three-way pipe 128 through the coolant pipeline on which the radiator 14 and the fifth solenoid valve 126 are connected in series in sequence. The C port of the eighth three-way pipe 121 is connected to the C port of the twelfth three-way pipe 129 through the coolant pipeline on which the second solenoid valve 123, the traction motor electronic control water jacket 17 and the traction motor water jacket 16 are connected in series in sequence. The C port of the ninth three-way pipe 122 is connected to the C port of the thirteenth three-way pipe 130 through a coolant pipeline having the third solenoid valve 124, the main pump motor electronic control water jacket 19 and the main pump motor water jacket 18 in series. The B port of the ninth three-way pipe 122 is connected to the B port of the thirteenth three-way pipe 130 through a coolant pipeline having the fourth solenoid valve 125, the auxiliary pump motor electronic control water jacket 21 and the auxiliary pump motor water jacket 20 in series.

[0061] The electric forklift integrated heat pump thermal management system in this application has multiple working modes, which can meet the thermal management requirements of each managed component under different working conditions, specifically:

[0062] In high temperature cooling mode:

[0063] The compressor 1 is started, the first water pump 11 is started and works with port A as the outlet, the second water pump 15 is started, the PTC heater 13 is turned off, the port A of the four-way reversing valve 2 is controlled to be connected to the port B, the port C is controlled to be connected to the port D, the port A of the first three-way reversing valve 116 is controlled to be connected to the port C, the port A of the second three-way reversing valve 118 is controlled to be connected to the port C, the port A of the third three-way reversing valve 119 is controlled to be connected to the port B, the first solenoid valve 114, the second solenoid valve 123, the third solenoid valve 124, the fourth solenoid valve 125 and the fifth solenoid valve 126 are controlled to be opened, so that the working medium flow paths in the refrigerant circuit and the coolant circuit are as follows: Figure 6 The solid line shows the flow direction, and the arrow indicates the flow direction.

[0064] The compressor 1 discharges high-temperature and high-pressure refrigerant vapor from the exhaust port, enters the cabin external heat exchanger 3 through the four-way reversing valve 2 to release heat and condense, and then enters the fifth three-way pipe 115 to be divided into two paths. One path is throttled by the first expansion valve 6, enters the cabin internal heat exchanger 7, absorbs heat from the cabin and evaporates, thereby cooling the cockpit, and finally enters the first three-way pipe 110 through the four-way reversing valve 2. The other path is throttled by the second expansion valve 8, enters the heat exchanger 9, absorbs heat from the coolant and evaporates, thereby cooling the coolant, and finally enters the first three-way pipe 110 through the first three-way reversing valve 116. The two refrigerants enter the gas-liquid separator 10 after merging in the first three-way pipe 110, and the refrigerant vapor separated by the gas-liquid separator 10 enters the air intake of the compressor 1, completing the refrigerant cycle.

[0065] The coolant cooled by the radiator 14 is pumped into the seventh three-way pipe 120 by the second water pump 15 and then divided into two paths. One path passes through the third three-way reversing valve 119, is further pressurized by the first water pump 11, enters the heat exchanger 9 through the second three-way reversing valve 118, releases heat to the refrigerant and is further cooled, then enters the battery liquid cooling plate 12 to absorb heat, thereby cooling the battery, and finally enters the eleventh three-way pipe 128. The other route passes through the eighth tee pipe 121 and the ninth tee pipe 122, and is further divided into three routes. The first route enters the traction motor electric control water jacket 17 and the traction motor water jacket 16 in sequence, and absorbs heat therefrom, thereby cooling the traction motor electric control and the traction motor. The second route enters the main pump motor electric control water jacket 19 and the main pump motor water jacket 18 in sequence, and absorbs heat therefrom, thereby cooling the main pump motor electric control and the main pump motor. The third route enters the auxiliary pump motor electric control water jacket 21 and the auxiliary pump motor water jacket 20 in sequence, and absorbs heat therefrom, thereby cooling the auxiliary pump motor electric control and the auxiliary pump motor. Finally, the three routes of coolant are combined into one route through the twelfth tee pipe 129 and the thirteenth tee pipe 130, and enter the eleventh tee pipe 128. After the two routes of coolant are combined in the eleventh tee pipe 128, they enter the radiator to complete the coolant circulation.

[0066] Based on this mode, if the cabin does not need to be cooled, the first expansion valve 6 can be closed, so that the refrigeration circuit can only cool the coolant; if the outside temperature is low, or the battery heat load is not high, the second expansion valve 8 can be closed, and the A port and the B port of the second three-way reversing valve 118 can be controlled to be connected, so that the coolant can be cooled only through the radiator 14; if the temperature of the traction motor electronic control and the traction motor is lower than its target temperature, the second solenoid valve 123 on the branch where its water jacket is located can be closed, and if the main pump motor electronic control, the main pump motor or the auxiliary pump motor electronic control, the auxiliary pump motor does not need to be cooled, the operation is similar. Therefore, the system can realize the function of independently cooling each heat-managed component, so that when a certain component does not need to be cooled, the system working mode can be flexibly adjusted to achieve energy-saving operation.

[0067] In low temperature heat pump heating mode:

[0068] The compressor 1 is started, the first water pump 11 is started and works with the B port as the outlet, the second water pump 15 is turned off, the PTC heater 13 is turned on, the A port of the four-way reversing valve 2 is controlled to be connected to the D port, the B port is controlled to be connected to the C port, the A port of the first three-way reversing valve 116 is controlled to be connected to the B port, the A port of the second three-way reversing valve 118 is controlled to be connected to the C port, the A port of the third three-way reversing valve 119 is controlled to be connected to the C port, the first solenoid valve 114 is controlled to be opened, and the second solenoid valve 123, the third solenoid valve 124, the fourth solenoid valve 125 and the fifth solenoid valve 126 are controlled to be closed, so that the working medium flow paths in the refrigerant circuit and the coolant circuit are as follows: Figure 7 The solid line shows the flow direction, and the arrow indicates the flow direction.

[0069] The compressor 1 discharges high-temperature and high-pressure refrigerant vapor from the exhaust port, and enters the second three-way pipe 111 through the four-way reversing valve 2 and is divided into two paths. One path enters the cabin internal heat exchanger 7 to release heat and condense, thereby heating the cabin cockpit, and then throttles through the first expansion valve 6, and finally enters the fifth three-way pipe 115. The other path enters the heat exchanger 9 after passing through the first three-way reversing valve 116, releases heat to the coolant and condenses, and then throttles through the second expansion valve 8, and finally enters the fifth three-way pipe 115. After the two refrigerants merge in the fifth three-way pipe 115, they enter the capillary 5 through the fourth three-way pipe 113 for further throttling, and then enter the cabin external heat exchanger 3 to absorb heat and evaporate, and finally enter the gas-liquid separator 10 through the four-way reversing valve 2 and the first three-way pipe 110. The refrigerant vapor separated by the gas-liquid separator 10 enters the air intake of the compressor 1, completing the refrigerant cycle.

[0070] The coolant after heating the battery by the battery liquid cooling plate 12 enters the heat exchanger 9, and after being heated by the refrigerant, enters the first water pump 11 through the second three-way reversing valve 118, and then is pumped into the PTC heater through the third three-way reversing valve 119 and the thirteenth pipe 127 for further heating, and finally enters the battery liquid cooling plate 12 to complete the coolant circulation.

[0071] Based on this mode, if the cabin does not need to be heated, the first expansion valve 6 can be closed, so that the heat pump cycle only heats the coolant. If the battery does not need to be heated, the second expansion valve 7 can be closed, so that the heat pump cycle only heats the cockpit. Therefore, the system can realize the function of independently heating each heat-managed component, so that when a certain component does not need to be heated, the system working mode can be flexibly adjusted to achieve energy-saving operation.

[0072] In addition, this mode uses the heat pump system and the PTC heater 13 to heat the battery simultaneously, which can not only achieve rapid preheating of the battery, but also improve the energy efficiency of the thermal management system in the process.

[0073] In low temperature waste heat recovery mode:

[0074] The compressor 1 is started, the first water pump 11 is turned on and works with the B port as the outlet, the second water pump 15 is turned off, the PTC heater 13 is turned on, the A port of the four-way reversing valve 2 is controlled to be connected to the D port, the B port is controlled to be connected to the C port, the A port of the first three-way reversing valve 116 is controlled to be connected to the C port, the A port of the second three-way reversing valve 118 is controlled to be connected to the C port, the A port of the third three-way reversing valve 119 is controlled to be connected to the B port, the first solenoid valve 114 and the fifth solenoid valve are controlled to be closed, and the second solenoid valve 123, the third solenoid valve 124 and the fourth solenoid valve 125 are controlled to be opened, so that the working medium flow paths in the refrigerant circuit and the coolant circuit are as follows: Figure 8 The solid line shows the flow direction, and the arrow indicates the flow direction.

[0075] The compressor 1 discharges high-temperature and high-pressure refrigerant vapor from the exhaust port, enters the cabin internal heat exchanger 7 through the four-way reversing valve 2 to release heat and condense, thereby heating the cabin, and then enters the second expansion valve 8 through the first expansion valve 6 and the fifth three-way valve 115 to throttle, and then enters the heat exchanger 9 to evaporate and absorb heat from the coolant, and finally enters the gas-liquid separator 10 through the first three-way reversing valve 116 and the first three-way pipe 110. The refrigerant vapor separated by the gas-liquid separator 10 enters the air intake port of the compressor 1, completing the refrigerant cycle.

[0076] The coolant, which is cooled by releasing heat to the refrigerant through the heat exchanger 9, is then pumped out by the first water pump 11 through the second three-way reversing valve 118, and then enters the ninth three-way pipe 121 and the thirteenth three-way pipe 122 through the third three-way reversing valve 119 and the seventh three-way pipe 120, and then is divided into three paths. The first path enters the traction motor electric control water jacket 17 and the traction motor water jacket 16 in sequence, and absorbs heat therefrom, the second path enters the main pump motor electric control water jacket 19 and the main pump motor water jacket 18 in sequence, and absorbs heat therefrom, the third path enters the auxiliary pump motor electric control water jacket 21 and the auxiliary pump motor water jacket 20 in sequence, and absorbs heat therefrom, and then the three paths of coolant are combined into one path through the twelfth three-way pipe 129 and the thirteenth three-way pipe 130, enter the PTC heater 13 for further heating, and then enter the battery cooling plate 12 to cool or heat the battery (cool when the battery temperature is higher than the target temperature, and heat otherwise), and finally enter the heat exchanger 9 to complete the coolant circulation.

[0077] On the basis of this mode, if the outlet coolant temperature of the branch where the traction motor electric control water jacket 17 and the traction motor water jacket 16 are located is lower than the inlet temperature, the second solenoid valve 123 on the branch can be closed to prevent heat loss. If the outlet coolant temperature of the branch where the main pump motor electric control water jacket 19, the main pump motor water jacket 18 or the auxiliary pump motor electric control water jacket 21, the auxiliary pump motor water jacket 20 are located is lower than the inlet temperature, the operation is similar. If there is no waste heat available in the three branches where the motor electric control and the motor water jacket are located, the A port of the third three-way reversing valve 119 is controlled to be connected to the C port, and the battery waste heat and the PTC heater 13 are used for heating. If the battery temperature is high, the first water pump 11 can be controlled to pump out the coolant from the A port, so that the coolant, which has been cooled by the heat exchanger 9 and released to the refrigerant, enters the battery liquid cooling plate to cool the battery. If the power of the battery, motor control and motor are all high, and the waste heat is sufficient, resulting in high temperatures of the battery, motor control and motor, the A port of the third three-way reversing valve 119 can be controlled to be connected to the C port, the fifth solenoid valve can be opened, and the second water pump 15 can be started, so that the coolant circulation is changed from a large circulation to two small circulations, one circulation uses the battery waste heat to heat the cabin, and the other circulation uses the radiator to the outside world to cool the motor control and motor.

[0078] In addition, in this mode, the PTC heater 13 controls the temperature of the coolant at the inlet of the battery liquid cooling plate, thereby avoiding the problem of battery performance degradation caused by heat extraction from the coolant circuit that may cause the battery temperature to be lower than the normal operating temperature.

[0079] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0080] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. Electric forklift integrated heat pump thermal management system, characterized by: It includes a refrigerant circuit and a coolant circuit, wherein: A refrigerant circuit, including a compressor, a four-way reversing valve, a cabin external heat exchanger, a one-way valve, a capillary tube, a first expansion valve, a cabin internal heat exchanger, a second expansion valve, a heat exchanger, and a gas-liquid separator; The coolant circuit includes a heat exchanger, a first water pump, a battery liquid cooling plate, a PTC heater, a radiator, a second water pump, a traction motor water jacket, a traction motor electronic control water jacket, a main pump motor water jacket, a main pump motor electronic control water jacket, an auxiliary pump motor water jacket, and an auxiliary pump motor electronic control water jacket.

2. The electric forklift integrated heat pump thermal management system according to claim 1, characterized in that: The refrigerant circuit further includes a first three-way pipe, a second three-way pipe, a third three-way pipe, a fourth three-way pipe, a first solenoid valve, and a fifth three-way pipe, wherein: The compressor exhaust port is connected to the port A of the four-way reversing valve, and the compressor air inlet is connected to the outlet of the gas-liquid separator; The B port of the four-way reversing valve is connected to one end of the heat exchanger outside the cabin, the C port of the four-way reversing valve is connected to the A port of the first three-way pipe, and the D port of the four-way reversing valve is connected to the A port of the second three-way pipe; The port B of the first three-way pipe is connected to the port C of the first three-way reversing valve, and the port C of the first three-way pipe is connected to the inlet of the gas-liquid separator; The port B of the second three-way pipe is connected to one end of the heat exchanger inside the cabin, and the port C of the second three-way pipe is connected to the port B of the first three-way reversing valve; The other end of the cabin external heat exchanger is connected to the A port of the third three-way pipe, the B port of the third three-way pipe is connected to the inlet of the one-way valve, the outlet of the one-way valve is connected to the A port of the fourth three-way pipe, and the C port of the third three-way pipe is connected to the C port of the fourth three-way pipe via a refrigerant pipe provided with a capillary tube; The B port of the fourth three-way pipe is connected to one end of the first solenoid valve, and the other end of the first solenoid valve is connected to the A port of the fifth three-way pipe; The port B of the fifth three-way pipe is connected to one end of the second expansion valve, the port C of the fifth three-way pipe is connected to one end of the first expansion valve, and the other end of the first expansion valve is connected to the other end of the heat exchanger inside the cabin; The other end of the second expansion valve is connected to one end of the heat exchanger on the refrigerant side, and the other end of the heat exchanger on the refrigerant side is connected to the A port of the first three-way reversing valve.

3. The electric forklift integrated heat pump thermal management system according to claim 2, characterized in that: The coolant circuit also includes a sixth three-way pipe, a second three-way reversing valve, a third three-way reversing valve, a seventh three-way pipe, an eighth three-way pipe, a ninth three-way pipe, a second solenoid valve, a third solenoid valve, a fourth solenoid valve, a fifth solenoid valve, a thirteenth three-way pipe, an eleventh three-way pipe, a twelfth three-way pipe, and a thirteenth three-way pipe, wherein: One end of the heat exchanger coolant side is connected to the C port of the sixth three-way pipe, and the other end of the heat exchanger coolant side is connected to the C port of the second three-way reversing valve; The B port of the sixth three-way pipe is connected to the B port of the second three-way reversing valve, and the A port of the sixth three-way pipe is connected to the A port of the thirteenth pipe through the coolant pipeline of the battery liquid cooling plate and the PTC heater connected in series in sequence; The port A of the first water pump is connected to the port A of the second three-way reversing valve, and the port B of the first water pump is connected to the port A of the third three-way reversing valve; The C port of the third three-way reversing valve is directly connected to the C port of the thirteenth three-way pipe via a coolant pipe, and the B port of the third three-way reversing valve is connected to the A port of the seventh three-way pipe; The port A of the eighth three-way pipe is connected to the port B of the seventh three-way pipe, and the port B of the eighth three-way pipe is connected to the port A of the ninth three-way pipe; The port B of the thirteenth through-pipe is connected to the port A of the eleventh three-way pipe; The port A of the twelfth tee is connected to the port B of the eleventh tee, and the port B of the twelfth tee is connected to the port A of the thirteenth tee; The outlet of the second water pump is connected to the C port of the seventh three-way pipe, and the inlet of the second water pump is connected to the C port of the eleventh three-way pipe through a coolant pipeline which is connected in series with a radiator and a fifth solenoid valve in sequence; The C port of the eighth tee is connected to the C port of the twelfth tee through a coolant pipeline on which a second solenoid valve, a traction motor electronic control water jacket, and a traction motor water jacket are sequentially connected; The C port of the ninth tee is connected to the C port of the thirteenth tee through a coolant pipeline on which a third solenoid valve, a main pump motor electric control water jacket and a main pump motor water jacket are sequentially connected; The B port of the ninth three-way pipe is connected to the B port of the thirteenth three-way pipe through a coolant pipeline on which the fourth solenoid valve, the auxiliary pump motor electronic control water jacket and the auxiliary pump motor water jacket are sequentially connected.

4. The electric forklift integrated heat pump thermal management system according to claim 3, characterized in that: In high-temperature cooling mode: the compressor starts, the first water pump starts and works with port A as the outlet, the second water pump starts, the PTC heater is turned off, the port A of the four-way reversing valve is controlled to be connected to the port B, the port C and the port D are controlled to be connected, the port A of the first three-way reversing valve is controlled to be connected to the port C, the port A of the second three-way reversing valve is controlled to be connected to the port C, the port A of the third three-way reversing valve is controlled to be connected to the port B, and the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve and the fifth solenoid valve are controlled to be opened; The compressor discharges high-temperature and high-pressure refrigerant vapor from the exhaust port, enters the cabin external heat exchanger through the four-way reversing valve to release heat and condense, and then enters the fifth three-way pipe to be divided into two paths: one path enters the cabin internal heat exchanger after being throttled by the first expansion valve, absorbs heat from the cabin and evaporates, thereby cooling the cockpit, and finally enters the first three-way pipe through the four-way reversing valve; the other path enters the heat exchanger after being throttled by the second expansion valve, absorbs heat from the coolant and evaporates, thereby cooling the coolant, and finally enters the first three-way pipe through the first three-way reversing valve; the two refrigerants enter the gas-liquid separator after merging in the first three-way pipe, and the refrigerant vapor separated by the gas-liquid separator enters the compressor suction port, completing the refrigerant cycle; The coolant that has been cooled by the radiator and dissipated heat to the outside is pumped into the seventh three-way pipe by the second water pump and then divided into two paths: one path passes through the third three-way reversing valve, is further pressurized by the first water pump, enters the heat exchanger through the second three-way reversing valve, releases heat to the refrigerant and is further cooled, then enters the battery liquid cooling plate to absorb heat, thereby cooling the battery, and finally enters the eleventh three-way pipe; the other path passes through the eighth three-way pipe and the ninth three-way pipe and is further divided into three paths. The first path enters the traction motor electronic control water jacket and the traction motor water jacket in turn, and absorbs heat therefrom, thereby The traction motor electronic control and traction motor are cooled. The second route enters the main pump motor electronic control water jacket and the main pump motor water jacket in turn, and absorbs heat therefrom, thereby cooling the main pump motor electronic control and the main pump motor. The third route enters the auxiliary pump motor electronic control water jacket and the auxiliary pump motor water jacket in turn, and absorbs heat therefrom, thereby cooling the auxiliary pump motor electronic control and the auxiliary pump motor. Finally, the three routes of coolant are combined into one route through the twelfth tee and the thirteenth tee, and enter the eleventh tee; after the two routes of coolant are combined at the eleventh tee, they enter the radiator to complete the coolant circulation.

5. The electric forklift integrated heat pump thermal management system according to claim 4, characterized in that: In high-temperature cooling mode: if the cabin does not need to be cooled, close the first expansion valve, so that the refrigeration circuit can only cool the coolant; if the outside temperature is low, or the battery heat load is not high, close the second expansion valve, control the connection between port A and port B of the second three-way reversing valve, so that the coolant can be cooled only through the radiator; if the temperature of the traction motor electronic control and the traction motor is lower than its target temperature, close the second solenoid valve on the branch where its water jacket is located. If the main pump motor electronic control, the main pump motor or the auxiliary pump motor electronic control, the auxiliary pump motor does not need to be cooled, the operation is the same.

6. The electric forklift integrated heat pump thermal management system according to claim 3, characterized in that: In low temperature heat pump heating mode: The compressor starts, the first water pump starts and works with port B as the outlet, the second water pump is turned off, the PTC heater is turned on, the A port of the four-way reversing valve is controlled to be connected to the D port, the B port is controlled to be connected to the C port, the A port of the first three-way reversing valve is controlled to be connected to the B port, the A port of the second three-way reversing valve is controlled to be connected to the C port, the A port of the third three-way reversing valve is controlled to be connected to the C port, the first solenoid valve is controlled to be opened, and the second solenoid valve, the third solenoid valve, the fourth solenoid valve and the fifth solenoid valve are controlled to be closed; The compressor discharges high-temperature and high-pressure refrigerant vapor from the exhaust port, and after entering the second three-way pipe through the four-way reversing valve, it is divided into two paths: one path enters the heat exchanger inside the cabin to release heat and condense, thereby heating the cabin cockpit, and then throttles through the first expansion valve, and finally enters the fifth three-way pipe; the other path enters the heat exchanger after passing through the first three-way reversing valve, releases heat to the coolant and condenses, and then throttles through the second expansion valve, and finally enters the fifth three-way pipe; after the two refrigerant paths merge at the fifth three-way pipe, they enter the capillary tube through the fourth three-way pipe for further throttling, and then enter the heat exchanger outside the cabin to absorb heat and evaporate, and finally enter the gas-liquid separator through the four-way reversing valve and the first three-way pipe. The refrigerant vapor separated by the gas-liquid separator enters the compressor suction port, completing the refrigerant cycle; The coolant after heating the battery by the battery liquid cooling plate enters the heat exchanger, and after being heated by the refrigerant, enters the first water pump through the second three-way reversing valve, and then is pumped into the PTC heater through the third three-way reversing valve and the thirteenth pipe for further heating, and finally enters the battery liquid cooling plate to complete the coolant circulation.

7. The electric forklift integrated heat pump thermal management system according to claim 6, characterized in that: In low-temperature heat pump heating mode: if the cabin does not need to be heated, close the first expansion valve to achieve heat pump circulation to heat only the coolant; if the battery does not need to be heated, close the second expansion valve to achieve heat pump circulation to heat only the cockpit.

8. The electric forklift integrated heat pump thermal management system according to claim 3, characterized in that: In low temperature waste heat recovery mode: The compressor starts, the first water pump starts and works with port B as the outlet, the second water pump is turned off, the PTC heater is turned on, the A port of the four-way reversing valve is controlled to be connected to the D port, the B port is controlled to be connected to the C port, the A port of the first three-way reversing valve is controlled to be connected to the C port, the A port of the second three-way reversing valve is controlled to be connected to the C port, the A port of the third three-way reversing valve is controlled to be connected to the B port, the first solenoid valve and the fifth solenoid valve are controlled to be closed, and the second solenoid valve, the third solenoid valve and the fourth solenoid valve are controlled to be opened; The compressor discharges high-temperature and high-pressure refrigerant vapor from the exhaust port, enters the heat exchanger inside the cabin through the four-way reversing valve to release heat and condense, thereby heating the cabin, then enters the second expansion valve through the first expansion valve and the fifth three-way valve to throttle, then enters the heat exchanger to evaporate and absorb heat from the coolant, and finally enters the gas-liquid separator through the first three-way reversing valve and the first three-way pipe. The refrigerant vapor separated by the gas-liquid separator enters the compressor suction port, completing the refrigerant cycle; The coolant that has been cooled by releasing heat to the refrigerant through the heat exchanger is pumped out by the first water pump through the second three-way reversing valve, and then passes through the third three-way reversing valve and the seventh three-way pipe, enters the ninth three-way pipe and the thirteenth three-way pipe and is divided into three paths; the first path enters the traction motor electronic control water jacket and the traction motor water jacket in turn and absorbs heat therefrom, the second path enters the main pump motor electronic control water jacket and the main pump motor water jacket in turn and absorbs heat therefrom, the third path enters the auxiliary pump motor electronic control water jacket and the auxiliary pump motor water jacket in turn and absorbs heat therefrom, and then the three paths of coolant are combined into one path through the twelfth three-way pipe and the thirteenth three-way pipe, enter the PTC heater for further heating, and then enter the battery cooling plate to cool or heat the battery, and finally enter the heat exchanger to complete the coolant circulation.

9. The electric forklift integrated heat pump thermal management system according to claim 8, characterized in that: In low-temperature waste heat recovery mode: if the outlet coolant temperature of the traction motor electronic control water jacket and the branch where the traction motor water jacket is located is lower than the inlet temperature, close the second solenoid valve on the branch to prevent heat loss. If the outlet coolant temperature of the main pump motor electronic control water jacket, the main pump motor water jacket or the auxiliary pump motor electronic control water jacket, and the branch where the auxiliary pump motor water jacket is located is lower than the inlet temperature, the operation is similar; if there is no waste heat available in the three branches where the motor electronic control and the motor water jacket are located, control the A port of the third three-way reversing valve to be connected to the C port, and use the battery waste heat and the PTC heater for heating; if the battery temperature is high, control the first water pump to pump out the coolant from the A port, so that the coolant that has been cooled by the heat exchanger and releases heat to the refrigerant enters the battery liquid cooling plate to cool the battery; If the power of the battery, motor control and motor are all high, and the waste heat is sufficient, resulting in high temperatures of the battery, motor control and motor, control the connection between port A and port C of the third three-way reversing valve, open the fifth solenoid valve, and start the second water pump, so that the coolant circulation is changed from a large circulation to two small circulations. One circulation uses the waste heat of the battery to heat the cabin, and the other circulation uses the radiator to the outside world to cool the motor control and motor.

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