CN108489144B - Drying system using cascade multi-connected heat pump - Google Patents

Abstract

The invention relates to a drying system using a cascade multi-connected heat pump, comprising a drying tunnel, a lower heating assembly, an upper heating assembly and a heat pump main engine. In order to provide hot air to the drying tunnel, the upper heating assembly is located above the drying tunnel, and several are arranged along the length of the drying tunnel to provide hot air to the drying tunnel. Each of the lower heating assembly and the upper heating assembly provides heat separately. Compared with the prior art, the present invention adopts a cascade heat pump cycle to meet the high temperature requirements of drying. The present invention adopts a multi-connected heat exchanger arrangement and a connecting pipe network, and the air does not need to be centrally heated and then uses an air pipe for distribution. , in the present invention, the fresh air is preheated by the subcooler to improve the circulation efficiency.

Description

A drying system using cascaded multi-connected heat pumps

technical field

The invention relates to a drying system of a lithium battery pole piece coating machine, in particular to a drying system using a cascade multi-connected heat pump.

Background technique

The drying process of lithium-ion batteries is one of the key processes in the entire battery manufacturing and plays a decisive role in battery performance. The investment of a coating machine mainly depends on the drying technology. The drying efficiency directly determines the coating line speed, and the drying uniformity affects the coating quality. The purpose of the drying process is to remove from the coating those inactive solvents (carriers) that are used inside the coating to suspend, dissolve or disperse the active ingredients (polymers, binders, etc.), so that the wet coating becomes Even dry coating. In the lithium battery production process, the drying process of the battery pole piece has the highest requirements, and the optimal drying temperature is 120 °C.

Lithium battery pole piece drying is to put the coated pole piece into the drying tunnel through the traction device for drying, and the water or solvent in the coating will be taken away by the dry hot air. The traditional drying tunnel usually uses an electric heater to directly heat the air (CN102423749 B), which consumes a lot of energy. If the electric heater fails, an NMP (N-methylpyrrolidone) explosion accident may occur, posing a serious safety hazard.

The use of air source heat pumps can effectively improve the efficiency of electric energy use and reduce safety risks. CN 203329954 U discloses a technical scheme in which air is centrally heated by a single-stage air source heat pump and then fed into a drying tunnel. However, due to the large heating capacity of the drying tunnel of the lithium battery pole piece, if the mode of centrally heating the air and then supplying the air to each air outlet is adopted, not only the heat energy loss in the air duct is serious, but also the fan power consumption is very high. CN 206019086 U discloses a method of using a heat pump to alleviate energy waste when NMP is recovered by a coating machine drying tunnel, but the heating capacity of the above-mentioned device is not enough to meet all heating requirements, and additional heating capacity still needs to be supplemented. Moreover, the above two technical solutions both use a single compressor to construct a single-stage heat pump, which is very difficult to achieve 120 °C, and has a low energy efficiency coefficient and limited energy saving effect.

Due to the high drying temperature of the pole piece, a cascade heat pump should be used. The respective compression ratios of the high and low temperature refrigeration systems of the cascade heat pump are relatively small, the operation is relatively stable, and the energy efficiency ratio is high. CN 205332764 U discloses a dryer using a cascade heat pump, which can centrally heat air and achieve a higher drying temperature. However, if the solution is directly applied to the heating tunnel of the lithium battery pole piece, the problems of serious heat loss and high fan power consumption cannot be avoided.

SUMMARY OF THE INVENTION

In order to make the heat pump system meet the high temperature requirements for drying lithium battery pole pieces (the oven temperature is 100°C to 120°C) and reduce the heat loss during air transportation as much as possible, the present invention proposes a drying method using a cascade multi-connected heat pump. dry system.

The object of the present invention can be realized through the following technical solutions:

A drying system using a cascade multi-connected heat pump, comprising:

Baking Road:

Lower heating assembly: located below the drying tunnel, several along the length of the drying tunnel to provide hot air to the drying tunnel;

Upper heating assembly: located above the drying tunnel, several along the length of the drying tunnel to provide hot air to the drying tunnel;

Heat pump host: set up one, connect with each lower heating component and upper heating component, and supply heat to each lower heating component and upper heating component respectively.

In an embodiment of the present invention, a cascade heat pump system is arranged in the heat pump main engine, and the main structure includes a low temperature heat pump cycle and a high temperature heat pump cycle.

In one embodiment of the present invention, a main engine air pipe interface and a main engine liquid pipe interface are provided on the casing of the heat pump main engine, and the main components of the heat pump main engine include an evaporator fan, a low-temperature evaporator, a low-temperature compressor, an intermediate heat exchanger, Low temperature throttling device, high temperature throttling device, regenerator and high temperature compressor, the low temperature evaporator is an air-refrigerant heat exchanger, which is provided with a refrigerant flow path and an air flow path. Heater, micro-channel heat exchanger, etc.; the evaporator fan is arranged close to the air flow path of the low-temperature evaporator, and the intermediate heat exchanger and the regenerator are both refrigerant-refrigerant heat exchangers with high-temperature refrigerant. Flow path and low temperature refrigerant, common forms such as plate heat exchanger, casing heat exchanger, etc.; the low temperature compressor, the high temperature refrigerant flow path of the intermediate heat exchanger, the low temperature throttling device, the refrigerant of the low temperature evaporator The flow paths are connected in sequence through the refrigerant connection pipes to form a low temperature heat pump cycle; the main body liquid pipe interface, the high temperature refrigerant flow path of the regenerator, the high temperature throttling device, the low temperature refrigerant flow path of the intermediate heat exchanger, the return The low temperature refrigerant flow path of the heater, the high temperature compressor, and the air pipe interface of the main engine are sequentially connected through the refrigerant connecting pipe in sequence to form a high temperature heat pump cycle in the heat pump main engine; the low temperature heat pump cycle and the high temperature heat pump cycle use different refrigerants.

In an embodiment of the present invention, the heat pump host can be placed in the production workshop or outdoors.

In an embodiment of the present invention, the low-temperature throttling device and the high-temperature throttling device may be common throttling devices for refrigeration equipment such as expansion valves, orifice plates, short pipes, and capillary tubes.

In one embodiment of the present invention, the lower heating assembly includes a lower return air duct, a fresh air duct, a lower supply air duct, a lower fan and a lower heating box, and one end of the lower return air duct is connected to the drying tunnel, The other end is connected to the lower air supply duct, one end of the fresh air duct is connected to the external environment, and the other end is connected to the lower air supply air duct, the lower air supply air duct is connected to the lower fan inlet, and the lower fan outlet is connected to the lower fan. One end of the lower heating box is connected, and the other end of the lower heating box is connected with the drying tunnel. The lower heating box is provided with a lower condenser, and the fresh air duct is provided with a subcooler. Both are air-refrigerant heat exchangers, provided with a refrigerant flow path and an air flow path. One end of the refrigerant flow path of the lower condenser is connected to the air pipe interface of the lower heating assembly, and the other end is connected to the subcooling through the refrigerant connection pipe. One end of the refrigerant flow path of the subcooler is connected to one end of the refrigerant flow path, and the other end of the refrigerant flow path of the subcooler is sequentially connected to the lower regulating valve and the liquid pipe interface of the lower heating assembly. The air pipe interfaces of the components are connected, and the main body liquid pipe interfaces are respectively connected with the liquid pipe interfaces of each lower heating assembly through a refrigerant connection pipe.

In an embodiment of the present invention, a lower auxiliary electric heater is further provided between the air outlet of the lower heating box and the lower condenser.

After the fresh air from the environment is heated by the subcooler, it is mixed with the return air from the drying tunnel, and then sent to the lower heating box through the lower fan, first through the lower condenser, and then heated to the specified temperature by the lower auxiliary electric heater, and finally sent to Baking Road.

In one embodiment of the present invention, the upper heating assembly includes an upper return air duct, a long air duct, an upper supply air duct, an upper fan and an upper heating box, and one end of the upper return air duct is connected to the drying tunnel, The other end is connected with the long air duct, the long air duct is connected with one end of the upper air supply air duct, the other end of the upper air supply air duct is connected with the upper fan inlet, and the upper fan outlet is connected with one end of the upper heating box, so The other end of the upper heating box is connected with the drying tunnel, and the upper heating box is provided with an upper condenser, the upper condenser is an air-refrigerant heat exchanger, and is provided with a refrigerant flow path and an air flow path. One end of the refrigerant flow path of the upper condenser is sequentially connected to the upper regulating valve and the liquid pipe interface of the upper heating assembly, and the other end is connected to the air pipe interface of the upper heating assembly. The air pipe interfaces are connected, and the main body liquid pipe interface is respectively connected with the liquid pipe interface of each upper heating assembly through a refrigerant connection pipe.

In an embodiment of the present invention, an upper auxiliary electric heater is further provided between the air outlet of the upper heating box and the upper condenser.

The return air from the drying duct enters the long air duct through the upper return air duct and mixes with the return air from other positions in the drying duct, and then is sent to the upper heating box through the upper fan, first passes through the upper condenser, and then is heated by the upper auxiliary electric heater. to the specified temperature, and finally sent to the drying tunnel.

In an embodiment of the present invention, the lower regulating valve and the upper regulating valve are electronic expansion valves, the function of which is to control the flow of refrigerant through the heating assembly and the temperature of the air entering the drying tunnel from the heating box.

In an embodiment of the present invention, the function of the lower auxiliary electric heater and the upper auxiliary electric heater is to assist in raising the air temperature when the heating amount is insufficient.

In an embodiment of the present invention, an exhaust assembly is provided on the long air duct, and the exhaust assembly is composed of a front exhaust air duct, an exhaust fan, and a rear exhaust air duct. One end of the front exhaust air duct is It is connected to the long air duct, the other end is connected to the inlet of the exhaust fan, and the outlet of the exhaust fan is connected to the rear exhaust air duct.

In an embodiment of the present invention, a support roller is provided in the drying tunnel, and the material to be dried moves on the support roller.

The air pipe interface of the main engine is communicated with the air pipe interface of each heating assembly through a refrigerant connection pipe, and the formed refrigerant connection pipe network structure is the same as that of the multi-connected air conditioning system. The main body liquid pipe interface is communicated with the liquid pipe interface of each heating assembly through a refrigerant connection pipe, and the formed refrigerant connection pipe network structure is the same as that of a multi-connected air conditioning system.

The invention uses the drying system of the cascade multi-connected heat pump, which is very suitable for use as the drying system of the lithium battery pole piece coating machine. It should be noted that the present invention is not only suitable for the drying of the lithium battery pole piece coating machine. The system is also suitable for other drying tunnel systems with drying temperatures ranging from 100°C to 120°C.

The present invention is characterized in that:

1. The cascade heat pump cycle is adopted to meet the high temperature requirements of lithium battery pole piece drying;

2. Using multi-connected heat exchanger arrangement and connecting pipe network, the air does not need to be centrally heated and then distributed by air pipes;

3. The fresh air is preheated through the subcooler to improve the circulation efficiency.

The beneficial effects of the present invention are:

1. The heating energy efficiency of the heat pump system is much higher than that of electric heating, which can greatly reduce production costs and save energy;

2. The distributed arrangement of heaters can avoid the use of large-scale air duct systems, save plant space, and reduce heat loss and fan power consumption during air transportation.

Description of drawings

FIG. 1 is a schematic diagram of the structure and process flow of a drying system using a cascade multi-connected heat pump in Example 1. FIG.

In the figure: 1 is the heat pump host, 2 is the drying tunnel, 3 is the backup roller, 4 is the material, 5 is the lower heating component, 6 is the upper heating component, 11 is the lower return air duct, 12 is the fresh air duct, 13 is the The lower air supply duct, 14 is the lower fan, 15 is the lower heating box, 16 is the upper return air duct, 17 is the long air duct, 18 is the upper air supply duct, 19 is the upper fan, and 20 is the upper heating box, 21 is the front exhaust air duct, 22 is the exhaust fan, 23 is the rear exhaust air duct, 31 is the lower condenser, 32 is the subcooler, 33 is the lower regulating valve, 34 is the refrigerant connection pipe, and 35 is the upper Regulating valve, 36 is the upper condenser, 37 is the liquid pipe interface of the lower heating assembly, 38 is the air pipe interface of the lower heating assembly, 39 is the liquid pipe interface of the upper heating assembly, 40 is the gas pipe interface of the upper heating assembly, 41 is the evaporator fan, 42 43 is a low temperature evaporator, 43 is a low temperature compressor, 44 is an intermediate heat exchanger, 45 is a low temperature throttling device, 46 is a high temperature throttling device, 47 is a regenerator, 48 is a high temperature compressor, and 49 is the main engine air pipe interface, 50 is the main engine liquid pipe interface, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 are the refrigerant connection pipes, 71 is the lower auxiliary electric heater, and 72 is the upper auxiliary electric heater.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Example 1

A drying system using a cascade multi-connected heat pump, as shown in FIG. 1 , includes a drying tunnel 2 , a lower heating assembly 5 , an upper heating assembly 6 , and a heat pump host 1 . The lower heating assembly 5 is located below the drying tunnel 2, and several are arranged along the length of the drying tunnel 2 to provide hot air to the drying tunnel 2. The upper heating element 6 is located above the drying tunnel 2, and several are arranged along the length of the drying tunnel 2. In order to provide hot air to the drying tunnel 2, one heat pump main engine 1 is provided, which is connected to each of the lower heating components 5 and the upper heating components 6, and supplies heat to each of the lower heating components 5 and the upper heating components 6 respectively.

In this embodiment, the heat pump host 1 is provided with a cascade heat pump system, and the main structure includes a low temperature heat pump cycle and a high temperature heat pump cycle. In an embodiment of the present invention, the heat pump host 1 is provided with a host air pipe interface 49 and a host liquid pipe interface 50 on the casing, and the main components of the heat pump host 1 include an evaporator fan 41, a low-temperature evaporator 42, a low-temperature compressor 43, and an intermediate exchanger. Heater 44, low temperature throttling device 45, high temperature throttling device 46, regenerator 47 and high temperature compressor 48, low temperature evaporator 42 is an air-refrigerant heat exchanger, and is provided with a refrigerant flow path and an air flow path, Common forms such as finned-tube heat exchangers, micro-channel heat exchangers, etc.; the evaporator fan 41 is set close to the air flow path of the low-temperature evaporator 42, and the intermediate heat exchanger 44 and the regenerator 47 are both refrigerant-refrigerant heat exchange There are high temperature refrigerant flow paths and low temperature refrigerants, common forms such as plate heat exchangers, casing heat exchangers, etc.; 45. The refrigerant flow paths of the low-temperature evaporator 42 are sequentially connected through the refrigerant connection pipes 51, 52, 53, and 54 to form a low-temperature heat pump cycle; the host liquid pipe interface 50, the high-temperature refrigerant flow paths of the regenerator 47, The high-temperature throttling device 46, the low-temperature refrigerant flow path of the intermediate heat exchanger 44, the low-temperature refrigerant flow path of the regenerator 47, the high-temperature compressor 48, and the main air pipe interface 49 are connected through the refrigerant connection pipes 58, 59, 60, 55, 56 and 57 are connected in sequence to form a high temperature heat pump cycle in the heat pump host; the low temperature heat pump cycle and the high temperature heat pump cycle use different refrigerants.

In this embodiment, the heat pump host 1 can be placed in the production workshop or outdoors.

In this embodiment, the low-temperature throttling device 45 and the high-temperature throttling device 46 may be common throttling devices for refrigeration equipment such as expansion valves, orifice plates, short pipes, and capillary tubes.

In this embodiment, the lower heating assembly 5 includes a lower return air duct 11 , a fresh air duct 12 , a lower air supply duct 13 , a lower fan 14 and a lower heating box 15 , and one end of the lower return air duct 11 is connected to the drying duct 2 , the other end is connected with the lower air duct 13, one end of the fresh air duct 12 is connected with the external environment, the other end is connected with the lower air duct 13, the lower air duct 13 is connected with the inlet of the lower fan 14, and the outlet of the lower fan 14 It is connected with one end of the lower heating box 15, and the other end of the lower heating box 15 is connected with the drying tunnel 2. The lower heating box 15 is provided with a lower condenser 31, and the fresh air duct 12 is provided with a subcooler 32. The cooler 32 is an air-refrigerant heat exchanger, and is provided with a refrigerant flow path and an air flow path. One end of the refrigerant flow path of the lower condenser 31 is connected to the air pipe interface 38 of the lower heating assembly, and the other end is connected through a refrigerant connection pipe. 34 is connected to one end of the refrigerant flow path of the subcooler 32, the other end of the refrigerant flow path of the subcooler 32 is sequentially connected to the lower regulating valve 33 and the liquid pipe interface 37 of the lower heating assembly, and the air pipe interface 49 of the host is respectively connected through the refrigerant connection pipe. Connected to the gas pipe interface 38 of each lower heating assembly, and the main body liquid pipe interface 50 is respectively connected to the liquid pipe interface 37 of each lower heating assembly through a refrigerant connection pipe.

In this embodiment, a lower auxiliary electric heater 71 is also provided between the air outlet of the lower heating box 15 and the lower condenser 31 .

After the fresh air from the environment is heated by the subcooler 32, it is mixed with the return air from the drying tunnel 2, and then sent to the lower heating box 15 through the lower fan 14, first through the lower condenser 31, and then through the lower auxiliary electric heater 71. The specified temperature is finally sent to the drying tunnel 2.

In this embodiment, the upper heating assembly 6 includes an upper return air duct 16 , a long air duct 17 , an upper air supply air duct 18 , an upper fan 19 and an upper heating box 20 , and one end of the upper return air duct 16 is connected to the drying tunnel 2 , the other end is connected with the long air duct 17, the long air duct 17 is connected with one end of the upper air supply air duct 18, the other end of the upper air supply air duct 18 is connected with the inlet of the upper fan 19, and the outlet of the upper fan 19 is connected with one end of the upper heating box 20 , the other end of the upper heating box 20 is connected to the drying tunnel 2, the upper heating box 20 is provided with an upper condenser 36, the upper condenser 36 is an air-refrigerant heat exchanger, and is provided with a refrigerant flow path and an air flow path. One end of the refrigerant flow path of the condenser 36 is sequentially connected to the upper regulating valve 35 and the liquid pipe interface 39 of the upper heating assembly, and the other end is connected to the air pipe interface 40 of the upper heating assembly. The gas pipe interface 40 of the heating assembly is connected, and the main body liquid pipe interface 50 is respectively connected with the liquid pipe interface 39 of each upper heating assembly through a refrigerant connection pipe.

In this embodiment, an upper auxiliary electric heater 72 is further provided between the air outlet of the upper heating box 20 and the upper condenser 36 .

The return air from the drying tunnel 2 enters the long air duct 17 through the upper return air duct 16 and mixes with the return air from other positions in the drying tunnel, and then is sent to the upper heating box 20 through the upper fan 19, first passes through the upper condenser 36, and then passes through the upper condenser 36. The upper auxiliary electric heater 72 is heated to a specified temperature, and finally sent to the drying tunnel 2 .

In this embodiment, the lower regulating valve 33 and the upper regulating valve 35 are electronic expansion valves, whose function is to control the flow of refrigerant passing through the heating assembly and the temperature of the air entering the drying tunnel from the heating box.

In this embodiment, the function of the lower auxiliary electric heater 71 and the upper auxiliary electric heater 72 is to assist in raising the air temperature when the heating amount is insufficient.

In this embodiment, the long air duct 17 is provided with an air exhaust assembly. The air exhaust assembly is composed of a front exhaust air duct 21, an exhaust fan 22, and a rear exhaust air duct 23. One end of the front exhaust air duct 21 is connected to the long air duct 21. On the air duct 17 , the other end is connected to the inlet of the exhaust fan 22 , and the outlet of the exhaust fan 22 is connected to the rear exhaust air duct 23 .

In this embodiment, a support roller 3 is arranged in the drying tunnel 2 , and the material 4 to be dried moves on the support roller 3 . For the lithium battery pole piece coating machine drying system, the material is the pole piece.

The main air pipe interface 49 is connected to the air pipe interface 38 of each lower heating assembly, the air pipe interface 40 of the upper heating assembly is communicated with the refrigerant connection pipe, the main liquid pipe interface 50 is connected to the liquid pipe interface 37 of each lower heating assembly, and the liquid pipe interface 39 of the upper heating assembly is connected through the refrigeration The agent connecting pipe is connected. The network structure of the refrigerant connecting pipes is the same as that of the multi-connected air-conditioning system, please refer to Fig. 1 or the schematic diagram of connecting pipes of internal and external units in CN20110077Y.

The working principle of the system is that after the refrigerant in the low-temperature evaporator 42 absorbs heat from the environment (air or water), it becomes a high-temperature and high-pressure refrigerant under the action of the low-temperature compressor 43, and then passes through the intermediate heat exchanger 44 to convert the heat energy. It is transferred to the high temperature cycle, and finally returns to the low temperature evaporator 42 through the low temperature throttling device 45 to complete the low temperature heat pump cycle. After the refrigerant in the high temperature heat pump cycle absorbs heat in the intermediate heat exchanger 44 , it first passes through the regenerator 47 to be supercooled and enters the high temperature throttling device 46 and then enters the high temperature compressor 48 . The high temperature compressor 48 discharges the high temperature and high pressure refrigerant gas through the main engine air pipe interface 49, the refrigerant is connected to the pipe network, and reaches the heating component to release heat. Using the regulating valve, the refrigerant flow through the lower heating assembly 5 and the upper heating assembly 6 can be controlled, and finally the temperature of the air entering the drying tunnel 2 can be controlled. The condensed refrigerant liquid is then returned to the low-temperature refrigerant channel 44 of the intermediate heat exchanger through the refrigerant connection pipeline, the main body liquid pipe interface 50, the high-temperature refrigerant flow path of the regenerator 47, and the high-temperature throttling device 46 to complete the process. High temperature heat pump cycle. When the heating amount is insufficient, the lower auxiliary electric heater 71 and the upper auxiliary electric heater 72 are turned on to increase the air temperature.

It should be noted that the number of heating components used in a single drying tunnel is not limited (the number of upper and lower heating components can be equal or unequal), the number of condensers connected to the heat pump host is unlimited, and the exhaust components on the long air duct 17 The quantity is non-limiting, and changing the quantity of the above components should belong to the protection scope of the present invention. Using multiple compressors in parallel to form a high-temperature compressor or a low-temperature compressor can achieve the purpose of increasing the heating capacity, but it does not belong to the substantial improvement of the present invention, and should belong to the protection scope of the present invention.

Herein, words such as "upper" and "lower" are used to define components, and those skilled in the art should know that the use of words such as "upper" and "lower" is only for the convenience of distinguishing components in description. Unless otherwise stated, the above terms have no special meaning.

All the components of the refrigerant cycle are not fully shown in the above embodiment. During the implementation process, common refrigeration accessories such as accumulators, gas-liquid separators, oil separators, filters, and dryers installed in the refrigerant circuit cannot be regarded as such. Substantial improvements have been made to the present invention, which should belong to the protection scope of the present invention.

The foregoing description of the embodiments is provided to facilitate understanding and use of the invention by those of ordinary skill in the art. It will be apparent to those skilled in the art that various modifications to these embodiments can be readily made, and the generic principles described herein can be applied to other embodiments without inventive step. Therefore, the present invention is not limited to the above-mentioned embodiments, and improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should all fall within the protection scope of the present invention.

Claims (9)

1. a drying system using a cascade multi-connected heat pump, is characterized in that, comprising: Drying tunnel (2): Lower heating assembly (5): located below the drying tunnel (2), and several of which are arranged along the length of the drying tunnel (2) for providing hot air to the drying tunnel (2); Upper heating assembly (6): located above the drying tunnel (2), and several of which are arranged along the length of the drying tunnel (2) for providing hot air to the drying tunnel (2); Heat pump host (1): set one, connect with each lower heating assembly (5) and upper heating assembly (6), and supply heat to each lower heating assembly (5) and upper heating assembly (6) respectively; The heat pump host (1) casing is provided with a host air pipe interface (49) and a host liquid pipe interface (50); The lower heating assembly (5) includes a lower return air duct (11), a fresh air duct (12), a lower air supply air duct (13), a lower fan (14) and a lower heating box (15). One end of the return air duct (11) is connected with the drying duct (2), the other end is connected with the lower air supply air duct (13), one end of the fresh air duct (12) is connected with the external environment, and the other end is connected with the lower air supply air The lower air supply air duct (13) is connected with the inlet of the lower fan (14), the outlet of the lower fan (14) is connected with one end of the lower heating box (15), and the lower heating box (15) ) is connected to the drying tunnel (2) at the other end, A lower condenser (31) is arranged in the lower heating box (15), and a subcooler (32) is arranged in the fresh air duct (12), The lower condenser (31) and the subcooler (32) are both air-refrigerant heat exchangers, and are provided with a refrigerant flow path and an air flow path, One end of the refrigerant flow path of the lower condenser (31) is connected to the air pipe interface (38) of the lower heating assembly, and the other end is connected to one end of the refrigerant flow path of the subcooler (32) through a refrigerant connection pipe. The other end of the refrigerant flow path of the cooler (32) is sequentially connected to the lower regulating valve (33) and the liquid pipe interface (37) of the lower heating assembly, The main body air pipe interface (49) is respectively connected with each lower heating assembly air pipe interface (38), and the main main body liquid pipe interface (50) is respectively connected with each lower heating assembly liquid pipe interface (37). 2 . A drying system using a cascaded multi-connected heat pump according to claim 1 , wherein the heat pump host ( 1 ) comprises a low temperature heat pump cycle and a high temperature heat pump cycle. 3 . 3. A drying system using a cascade multi-connected heat pump according to claim 2, wherein the heat pump main engine (1) comprises an evaporator fan (41), a low temperature evaporator (42), a low temperature a compressor (43), an intermediate heat exchanger (44), a low temperature throttling device (45), a high temperature throttling device (46), a regenerator (47) and a high temperature compressor (48), The low-temperature evaporator (42) is an air-refrigerant heat exchanger, and is provided with a refrigerant flow path and an air flow path, and the evaporator fan (41) is arranged close to the air flow path of the low-temperature evaporator (42), The intermediate heat exchanger (44) and the regenerator (47) are both refrigerant-refrigerant heat exchangers, and are provided with a high-temperature refrigerant flow path and a low-temperature refrigerant, The low-temperature compressor (43), the high-temperature refrigerant flow path of the intermediate heat exchanger (44), the low-temperature throttling device (45), and the refrigerant flow path of the low-temperature evaporator (42) are sequentially connected through a refrigerant connection pipe in sequence , forming a low-temperature heat pump cycle; The main body liquid pipe interface (50), the high temperature refrigerant flow path of the regenerator (47), the high temperature throttling device (46), the low temperature refrigerant flow path of the intermediate heat exchanger (44), the regenerator (47) ) of the low-temperature refrigerant flow path, the high-temperature compressor (48), and the main engine gas pipe interface (49) are sequentially connected through the refrigerant connecting pipe in sequence to form a high-temperature heat pump cycle in the heat pump main engine; The low temperature heat pump cycle and the high temperature heat pump cycle use different refrigerants. 4. a kind of drying system using cascade multi-connected heat pump according to claim 3, is characterized in that, described main engine gas pipe interface (49) and main engine liquid pipe interface (50) simultaneously and each lower heating assembly (5) is connected to the upper heating assembly (6), and supplies heat to each of the lower heating assembly (5) and the upper heating assembly (6) respectively. 5. A kind of drying system using cascade multi-connected heat pump according to claim 1, is characterized in that, described lower heating box (15) air outlet and lower condenser (31) are also provided with lower Auxiliary electric heater (71). 6. A drying system using a cascade multi-connected heat pump according to claim 3, wherein the upper heating assembly (6) comprises an upper return air duct (16), a long air duct (17) ), an upper air supply air duct (18), an upper fan (19) and an upper heating box (20), one end of the upper return air duct (16) is connected with the drying duct (2), and the other end is connected with the long air duct ( 17) are connected, the long air duct (17) is connected with one end of the upper air supply air duct (18), and the other end of the upper air supply air duct (18) is connected with the inlet of the upper fan (19), and the upper fan (18) 19) The outlet is connected with one end of the upper heating box (20), and the other end of the upper heating box (20) is connected with the drying tunnel (2), The upper heating box (20) is provided with an upper condenser (36), the upper condenser (36) is an air-refrigerant heat exchanger, and is provided with a refrigerant flow path and an air flow path, One end of the refrigerant flow path of the upper condenser (36) is sequentially connected with the upper regulating valve (35) and the liquid pipe interface (39) of the upper heating assembly, and the other end is connected with the gas pipe interface (40) of the upper heating assembly, The main body air pipe interface (49) is respectively connected with each upper heating assembly air pipe interface (40), and the main main body liquid pipe interface (50) is respectively connected with each upper heating assembly liquid pipe interface (39). 7. A drying system using a cascaded multi-connected heat pump according to claim 6, wherein an upper heating box (20) is also provided between the air outlet and the upper condenser (36) Auxiliary electric heater (72). 8. A drying system using a cascade multi-connected heat pump according to claim 6, characterized in that, an exhaust assembly is provided on the long air duct (17), and the exhaust assembly consists of a front row. An air duct (21), an exhaust fan (22), and a rear exhaust air duct (23) are formed. One end of the front exhaust air duct (21) is connected to the long air duct (17), and the other end is connected to the exhaust air duct (21). The inlet of the fan (22) is connected, and the outlet of the exhaust fan (22) is connected with the rear exhaust air duct (23). 9. A drying system using a cascade multi-connected heat pump according to claim 1, characterized in that, a support roller (3) is provided in the drying tunnel (2), and the material to be dried (4) ) on the backup roller (3).

Images