A thermal management system for a locomotive traction battery

Abstract

The application relates to the field of rail transit heat exchange technology, in particular to a locomotive power battery heat management system. A top-mounted heat management system is provided, which can fully utilize the space on the top of the locomotive and reduce the occupation of the internal space of the locomotive; the heat management system is internally integrated with a cooling liquid circuit, a refrigerant circuit, an air circuit and a control system, can switch three working modes of air cooling mode, refrigeration mode and heating mode according to the external environment temperature, the power battery temperature and the preset temperature threshold, so that the power battery works in a suitable temperature range; the application further optimizes the structures of key components such as the position arrangement of each component and pipeline, the expansion water tank and the electric heater module, so as to solve specific problems such as the exhaust of the cooling liquid circuit and the precipitation resistance, and make the device more efficient and low-cost to realize the heat management of the locomotive power battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rail transit heat exchange technology, in particular to a heat management system for locomotive power battery. BACKGROUND

[0002] As the core energy source of the locomotive, the performance of the power battery directly affects the overall performance and endurance of the locomotive. However, a large amount of heat will be generated during the charging and discharging process of the power battery, and if the heat cannot be effectively managed, the temperature of the battery will rise, thereby affecting the safety, cycle life and performance of the battery. The heat management system of the locomotive power battery is a key system to ensure that the power battery maintains an appropriate working temperature in a complex operating environment, improves the performance and service life of the battery, and is crucial to maintaining the power battery within an appropriate working temperature range.

[0003] Since the usual operating environment temperature of the power locomotive is in the range of -40℃ to +40℃, in order to maintain the power battery working in an appropriate working temperature range, not only needs to cool it but also needs to heat it, and in the prior art, multiple independent systems are usually used to achieve it respectively, which cannot be centrally managed and arranged, and multiple compressors, condensers, fans and the like exist in multiple independent systems, which also increases the cost; therefore, a heat management system for locomotive power battery is needed to solve the above problems. SUMMARY

[0004] The purpose of the present application is to provide a heat management system for locomotive power battery.

[0005] The embodiments of the present application can be implemented by the following technical solutions:

[0006] A heat management system for locomotive power battery, comprising a box body and a water pump, a plate heat exchanger, a compressor, a gas-liquid separator, an electric heater module, a condenser, a fan, a radiator, an expansion valve, a pipeline system for connecting various devices, a valve assembly provided on the pipeline system for controlling the on-off thereof and a control system arranged inside the box body; wherein the pipeline system comprises a cooling liquid pipeline system and a refrigerant pipeline system, the water pump, the cooling liquid side of the plate heat exchanger and the electric heater module are connected in series through the cooling liquid pipeline system to form a first cooling liquid circuit; the water pump, the radiator and the electric heater module are connected in series through the cooling liquid pipeline system to form a second cooling liquid circuit; the refrigerant side of the plate heat exchanger, the gas-liquid separator, the compressor, the condenser and the expansion valve are connected in series through the refrigerant pipeline system to form a refrigerant circuit; the radiator and the fan form a first air circuit; the condenser and the fan form a second air circuit; one or more devices and pipelines are shared between the circuits; the control system realizes the switching of three modes of refrigeration mode, air cooling mode and heating mode of the heat management system by controlling the operation of each device and the on-off of each circuit.

[0007] Further, when in the cooling mode, the first cooling liquid circuit, the refrigerant circuit and the second air circuit are communicated, the water pump, the plate heat exchanger, the gas-liquid separator, the compressor, the condenser, the fan and the expansion valve work; when in the air cooling mode, the second cooling liquid circuit and the first air circuit are communicated, the water pump, the radiator and the fan work; when in the heating mode, the first cooling liquid circuit and the second cooling liquid circuit are communicated, the water pump and the electric heater module work.

[0008] Further, the control system determines the switching of the cooling mode, the air cooling mode and the heating mode by the following steps:

[0009] S1, obtaining the ambient temperature and the temperature of the power battery;

[0010] S2, determining whether the ambient temperature is greater than a first preset temperature T1, if yes, entering the cooling mode; if no, proceeding to step S3;

[0011] S3, determining whether the ambient temperature is greater than a second preset temperature T2, if yes, entering the air cooling mode; if no, proceeding to step S4;

[0012] S4, determining whether the temperature of the power battery 4 is greater than a third preset temperature T3, if no, entering the heating mode.

[0013] Further, the cooling mode further includes a first-level cooling mode, a second-level cooling mode, a third-level cooling mode, a fourth-level cooling mode and a fifth-level cooling mode, which are selected by the following method:

[0014] Step 1, obtaining the average temperature T im of the cooling liquid in the first cooling liquid circuit;

[0015] Step 2, comparing the average temperature T im obtained in step 1 with a preset target temperature T ic of the cooling liquid, and selecting different cooling modes according to the comparison:

[0016] When T ic + 0.5 > T im ≥ T ic , the first-level cooling mode is selected;

[0017] When T ic + 0.8 > T im ≥ T ic + 0.5, the second-level cooling mode is selected;

[0018] When T ic + 1 > T im ≥ T ic + 0.8, the third-level cooling mode is selected;

[0019] When T ic +1.4>T im ≥T ic +1, select the fourth stage refrigeration mode;

[0020] When T im ≥T ic +1.4, select the fifth stage refrigeration mode.

[0021] Further, the control system comprises a frequency converter for frequency control of the compressor to realize switching of different refrigeration modes.

[0022] Further, the cooling liquid pipeline system comprises a first pipeline for connecting the outlet of the power battery end pipeline and the inlet of the plate heat exchanger, a second pipeline for connecting the outlet of the plate heat exchanger and the inlet of the water pump, a third pipeline for connecting the outlet of the water pump and the inlet of the electric heater module, a fourth pipeline for connecting the outlet of the electric heater module and the inlet of the power battery end pipeline, a fifth pipeline for connecting the first pipeline and the inlet of the radiator, and a sixth pipeline for connecting the outlet of the radiator and the inlet of the water pump; the third pipeline is located higher than other pipelines in the cooling liquid pipeline system.

[0023] Further, a third cooling liquid branch is further included, which comprises an expansion water tank, a liquid supplementing pipeline and an exhaust pipeline, the expansion water tank is connected in parallel with the cooling liquid pipeline shared by the first cooling liquid circuit and the second cooling liquid circuit through the liquid supplementing pipeline and the exhaust pipeline, and is used for exhausting and supplementing the cooling liquid circuit.

[0024] Further, one end of the liquid supplementing pipeline and the exhaust pipeline is connected to the expansion water tank, and the other end is connected to the cooling liquid pipeline shared by the first cooling liquid circuit and the second cooling liquid circuit, and the interface position of the exhaust pipeline and the cooling liquid pipeline is set so that the liquid level height of the cooling liquid in the expansion water tank continuously decreases when the cooling liquid circuit is in the exhaust stage.

[0025] Further, the electric heater module comprises a first electric heater device and a bypass pipeline arranged outside the first electric heater device, the first electric heater device is provided with an inlet pipeline and an outlet pipeline, and the bypass pipeline is used for connecting the inlet pipeline and the outlet pipeline.

[0026] Further, the rated power of the first electric heater device is 30-50 KW, the pipe diameter of the inlet pipeline and the outlet pipeline is 10-30 mm, and the pipe diameter of the bypass pipeline is less than 30 mm.

[0027] Further, the box is divided into two independent first cavity and second cavity, wherein the first cavity is arranged with plate heat exchanger, water pump, compressor and gas-liquid separator, and the second cavity is arranged with condenser, fan and radiator; the fan is arranged in the middle of the second cavity, the condenser is arranged on both sides of the fan along the radial direction of the fan, and the condenser is arranged obliquely relative to the axis of the fan.

[0028] The embodiment of the present application provides a heat management system for a locomotive power battery.

[0029] The heat management system of the present application is integrated with a cooling liquid circuit, a refrigerant circuit, an air circuit and a control system, and can switch among air cooling mode, refrigeration mode and heating mode according to the external environment temperature, the power battery temperature and the preset temperature threshold, so that the power battery works in a suitable temperature range; the present application further optimizes the structure of key components such as component position arrangement, expansion tank and electric heater module, to solve specific problems such as exhaust of the cooling liquid circuit and precipitation resistance, so that the system can more efficiently and at a lower cost realize the heat management of the locomotive power battery. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall structure of the heat management system of the embodiment of the present application;

[0031] Figure 2 It is a schematic diagram of the internal device layout of the heat management system of the embodiment of the present application;

[0032] Figure 3 It is a schematic diagram of the internal structure of the first cavity of the heat management system of the embodiment of the present application;

[0033] Figure 4 It is a schematic diagram of the internal structure of the second cavity of the heat management system of the embodiment of the present application;

[0034] Figure 5a It is a schematic diagram of the air cooling mode principle of the heat management system of the embodiment of the present application;

[0035] Figure 5b It is a schematic diagram of the refrigeration mode principle of the heat management system of the embodiment of the present application;

[0036] Figure 5c It is a schematic diagram of the heating mode principle of the heat management system of the embodiment of the present application;

[0037] Figure 6 It is a flow chart of the control method of the heat management system of the embodiment of the present application;

[0038] Figure 7 A schematic diagram of a cooling liquid pipeline system according to an embodiment of the present application;

[0039] Figure 8 A schematic diagram of a partial specific structure of a cooling liquid pipeline system according to an embodiment of the present application;

[0040] Figure 9 A schematic diagram of a partial specific structure of a cooling liquid pipeline system according to an embodiment of the present application;

[0041] Figure 10 A schematic diagram of a specific structure of an expansion water tank according to an embodiment of the present application;

[0042] Figure 11 A top view of an expansion water tank according to an embodiment of the present application;

[0043] Figure 12 A schematic diagram of a specific structure of an expansion water tank according to an embodiment of the present application; Figure 11 A cross-sectional view along A-A direction;

[0044] Figure 13 A cross-sectional view along B-B direction; Figure 11 A cross-sectional view along B-B direction;

[0045] Figure 14 A schematic diagram of a specific structure of an electric heater module according to an embodiment of the present application;

[0046] Figure 15 A schematic diagram of a specific structure of an electric heater module according to an embodiment of the present application;

[0047] Reference numerals in the drawings

[0048] tank 100, first cavity 100-1, second cavity 100-2, expansion water tank 1, upper water chamber 1-11, lower water chamber 1-12, water inlet 1-2, first water inlet 1-21, second water inlet 1-22, exhaust pipe joint 1-3, water supplement pipe joint 1-4, liquid level observation window 1-5, pressure relief valve 1-6, upper gas collection area 1-7, expansion water tank exhaust pipe 1-8, liquid level measuring instrument 1-9, plate heat exchanger 2, water pump 3, power battery 4, liquid supplement pipe 5, expansion water tank liquid supplement pipe 51, exhaust pipe 6, second exhaust pipe 61, cooling liquid pipeline system 7, plate heat exchanger water inlet pipe 71, second pipeline 72, third pipeline 73, fourth pipeline 74, fifth pipeline 75, sixth pipeline 76, compressor 8, gas-liquid separator 9, electric heater module 10, first electric heater device 101, liquid inlet pipe 1011, liquid outlet pipe 1012, electric heater external pipeline 102, bypass pipe 1021, first three-way pipe fitting 1022, second three-way pipe fitting 1023, electric control box 11, frequency converter 12, condenser 13, fan 14, radiator 15, electric three-way valve 16, expansion valve 17; DETAILED DESCRIPTION

[0049] The application will be further described below based on preferred embodiments and with reference to the drawings.

[0050] In addition, various components in the drawings are enlarged or reduced for convenience of understanding, but this practice is not intended to limit the protection scope of the application.

[0051] The singular form of the word also includes the plural meaning, and vice versa. In the description of the embodiments of the application, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer" and the like in the description of the embodiments of the application is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the embodiments of the application is usually placed, and is only for the convenience of describing the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. In addition, in the description of the application, in order to distinguish different units, the first, second and the like are used in the description, but these will not be limited by the order of manufacture, and cannot be understood as indicating or implying relative importance, and the name thereof may be different in the detailed description and the claims of the application.

[0052] The words in the specification are used to illustrate the embodiments of the application, but are not intended to limit the application. It should be noted that, unless otherwise specified and limited, if the terms "provided", "connected", "connected" appear, they should be understood in a broad sense, for example, they can be fixedly connected, or detachably connected, or integrally connected; can be mechanically connected, can be directly connected, or indirectly connected through an intermediate medium, can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood specifically.

[0053] The application provides a thermal management system for a locomotive power battery 4, which is installed on the top of the locomotive to cool, heat and perform thermal management on the locomotive power battery 4 arranged in the lower part thereof so that the power battery 4 works in a suitable temperature range. Since it is installed on the top of the locomotive, it is subject to some conditions such as size and shape matching the locomotive, and needs to integrate multiple devices, systems and the like in a limited space, which undoubtedly puts high requirements on the installation and arrangement of each system and device.

[0054] The thermal management system provided by some embodiments of the application will be described in detail below, combined with Figures 1 to 4It can be seen that it comprises a box body 100 and devices accommodated in the box body 100, pipelines for connecting the devices, valve assemblies provided on the pipelines for controlling the opening and closing of the pipelines, and a control system; specifically, the inside of the box body is divided into two mutually independent first cavity 100-1 and second cavity 100-2, wherein the first cavity 100-1 is arranged with an expansion water tank 1, a plate heat exchanger 2, a water pump 3, a compressor 8, a gas-liquid separator 9, an electric heater module 10 and an electric control box 11, and the second cavity 100-2 is arranged with a frequency converter 12, a condenser 13, a fan 14 and a radiator 15;

[0055] Specifically, the water pump 3, the cooling liquid side of the plate heat exchanger 2, and the electric heater module 10 are connected in series through pipelines and constitute a first cooling liquid circuit with the power battery 4; the water pump 3, the radiator 15, and the electric heater module 10 are connected in series through pipelines and constitute a second cooling liquid circuit with the power battery 4; the refrigerant side of the plate heat exchanger 2, the gas-liquid separator 9, the compressor 8, the condenser 13, and the expansion valve 17 are connected in series through pipelines to constitute a refrigerant circuit; the radiator 15 and the fan 14 constitute a first air circuit; the condenser 13 and the fan 14 constitute a second air circuit; one or more devices and pipelines are shared between the circuits; the control system can realize the switching of three modes of refrigeration mode, air cooling mode and heating mode of the thermal management system by controlling the operation of each device and the opening and closing of each circuit, which comprises the electric control box 11 and the frequency converter 12, and the frequency converter 12 can further realize the frequency control of the compressor 8, thereby realizing the switching of different refrigeration modes, and the frequency control can reduce the start-stop times of the compressor 8 and prolong the service life.

[0056] In some embodiments, the switching of the first cooling liquid circuit and the second cooling liquid circuit is realized by an electric three-way valve 16 provided on the pipeline, the first interface of the electric three-way valve 16 communicates with the radiator 15, the second interface communicates with the plate heat exchanger 2, and the third interface communicates with the water pump 3 or the power battery 4.

[0057] The following will be described in combination with Figure 5a , Figure 5b and Figure 5cThe schematic diagrams of each working mode are shown below for detailed explanation. In cooling mode, the first coolant circuit, refrigerant circuit, and second air circuit are connected. The water pump 3, plate heat exchanger 2, gas-liquid separator 9, compressor 8, condenser 13, fan 14, and expansion valve 17 are in operation. Specifically, the high-temperature coolant in the cooling pipe of the power battery 4 is pumped to the coolant side of the plate heat exchanger 2 by the water pump 3. After completing the convective heat exchange process with the refrigerant side of the plate heat exchanger 2, the low-temperature coolant flows back to the cooling pipe of the power battery 4 to cool the power battery 4. The refrigerant on the refrigerant side of the plate heat exchanger 2 absorbs heat from the coolant and becomes high-temperature and high-pressure vapor. After passing through the gas-liquid separator 9, it enters the compressor 8 for compression and becomes high-temperature and high-pressure vapor. Then it flows into the condenser 13 and is condensed in the condenser 13 through the second air circuit. The condensed liquid refrigerant passes through the expansion valve 17 to further reduce the pressure and temperature of the liquid refrigerant, and finally, the low-temperature and low-pressure liquid refrigerant flows back to the plate heat exchanger 2 for circulation.

[0058] When in air-cooled mode, the second coolant circuit and the first air circuit are connected, and the water pump 3, radiator 15 and fan 14 are working. Specifically, at this time, the high-temperature coolant at the power battery 4 is pumped to the radiator 15 by the water pump 3, and heats up through the first air circuit. The low-temperature coolant after releasing heat flows back to the cooling pipe at the power battery 4 to cool the power battery 4.

[0059] When in heating mode, the first coolant circuit and the second coolant circuit are connected, and the water pump 3 and the electric heater module 10 are working. Specifically, at this time, the low-temperature coolant from the cooling pipe of the power battery 4 is pumped to the electric heater module 10 for heating by the water pump 3, and the heated high-temperature coolant flows back to the power battery 4 to raise its temperature.

[0060] Furthermore, such as Figure 6 As shown, the control system can switch between different modes based on the ambient temperature, the temperature of the power battery 4, and a preset temperature threshold through the following steps:

[0061] S1, obtain the ambient temperature and the temperature of the power battery 4;

[0062] S2, determine whether the ambient temperature is greater than the first preset temperature T1. If yes, enter the cooling mode; otherwise, proceed to step S3.

[0063] S3, determine whether the ambient temperature is greater than the second preset temperature T2. If yes, enter the air cooling mode; otherwise, proceed to step S4.

[0064] S4, determine whether the temperature of the power battery 4 is greater than the third preset temperature T3. If not, enter the heating mode.

[0065] Furthermore, the cooling mode also includes the following steps:

[0066] Step 1: Obtain the average temperature T of the coolant in the first coolant circuit. im ;

[0067] Step 2, take the average temperature T obtained in Step 1. im With the preset target coolant temperature T ic The comparison is made, and the power of compressor 8 is adjusted accordingly to enter different cooling modes:

[0068] When T ic +0.5>T im ≥T ic At this time, use inverter 12 to adjust the power of compressor 8 to the first power and enter the first-level refrigeration mode;

[0069] When T ic +0.8>T im ≥T ic At +0.5, use inverter 12 to adjust the power of compressor 8 to the second power, and enter the second-stage refrigeration mode;

[0070] When T ic +1>T im ≥T ic At +0.8, use inverter 12 to adjust the power of compressor 8 to the third power, and enter the third-level refrigeration mode;

[0071] When T ic +1.4>T im ≥T ic At +1, use inverter 12 to adjust the power of compressor 8 to the fourth power, and enter the fourth-level refrigeration mode;

[0072] When T im ≥T ic At +1.4, use inverter 12 to adjust the power of compressor 8 to the fifth power, and enter the fifth-level cooling mode;

[0073] Furthermore, the specific arrangement of each device and the specific connection relationship between them are described in detail. In some specific embodiments, in order to realize the recycling of refrigerant, the plate heat exchanger 2, gas-liquid separator 9, compressor 8, condenser 13 refrigerant side and expansion valve 17 are connected in series through the refrigerant pipeline system in sequence.

[0074] To save space and equipment cost, one or more devices and pipelines are shared between circuits, in some embodiments, the first coolant circuit and the second coolant circuit share the water pump 3 and the electric heater module 10, the first coolant circuit and the refrigerant circuit share the plate heat exchanger 2, the first air circuit and the second air circuit share the fan 14;

[0075] In some preferred embodiments, the thermal management system further comprises a third coolant branch, the third coolant branch comprises an expansion tank 1 connected in parallel with the first coolant circuit and the second coolant circuit through pipelines, for liquid supplement and gas exhaust of the coolant circuits.

[0076] Figures 7 to 9 The specific structure of the coolant pipeline system 7 in some embodiments of the present application is shown in the figure, as shown, the coolant pipeline system 7 comprises a first pipeline 71 for connecting the end pipeline liquid outlet of the power battery 4 and the liquid inlet of the plate heat exchanger 2, a second pipeline 72 for connecting the liquid outlet of the plate heat exchanger 2 and the liquid inlet of the water pump 3, a third pipeline for connecting the liquid outlet of the water pump 3 and the liquid inlet of the electric heater module 10, a fourth pipeline 74 for connecting the liquid outlet of the electric heater module 10 and the liquid inlet of the end pipeline of the power battery 4, a fifth pipeline 75 for connecting the liquid inlet of the first pipeline 71 and the radiator 15, and a sixth pipeline 76 for connecting the liquid outlet of the radiator 15 and the liquid inlet of the water pump 3;

[0077] In some embodiments, the third pipeline 73 is arranged higher than other pipelines in the coolant pipeline system 7 to facilitate the circulation of the coolant based on the flow direction of the coolant.

[0078] In some embodiments, the electric three-way valve 16 is arranged on the first pipeline 71, and the liquid inlet of the radiator 15 is connected to the electric three-way valve 16 through the fifth pipeline 75, and the switching between the second coolant circuit and the first coolant circuit is realized by adjusting the electric three-way valve 16.

[0079] In some embodiments, the third coolant branch comprises an expansion tank 1, a liquid supplement pipeline 5 and a gas exhaust pipeline 6, the expansion tank 1 is connected in parallel with the first coolant circuit and the second coolant circuit through the gas exhaust pipeline 6 and the liquid supplement pipeline 5, specifically, one end of the liquid supplement pipeline 5 and the gas exhaust pipeline 6 is connected to the pipeline shared by the first coolant circuit and the second coolant circuit in the coolant pipeline system 7, and the other end is connected to the expansion tank 1, in use, the gas in the coolant circuit enters the expansion tank 1 through the gas exhaust pipeline 6 and is exhausted to the atmosphere by the expansion tank 1, when the coolant in the coolant circuit is insufficient, the pre-stored coolant in the expansion tank 1 is supplemented to the coolant circuit through the liquid supplement pipeline 5, so as to realize the liquid supplement and gas exhaust of the coolant circuit.

[0080] However, since the gas will generally gather at the high position of the pipeline during exhaust, the conventional operation in the field is to connect one end of the exhaust pipe 6 to the highest position of the third pipeline 73 in the cooling liquid circuit, which is located at the outlet of the water pump 3. However, the excessive pressure causes excessive cooling liquid to flow into the expansion tank 1 through the exhaust pipe 6, and the part of the cooling liquid flowing into the expansion tank 1 will be stored in the expansion tank 1 and will not flow back to the cooling liquid circuit, thus causing the water pump to be sucked empty.

[0081] Based on the above-mentioned problem of water pump suction, the applicant finds that connecting the exhaust pipe 6 to a specific pipeline position in the cooling liquid circuit can avoid the above-mentioned water pump suction phenomenon and ensure the exhaust effect of the circuit. Specifically, when the exhaust pipe 6 is connected to a specific pipeline position in the cooling liquid circuit, the liquid level height of the cooling liquid in the expansion tank 1 can continuously decrease during the exhaust stage of the cooling liquid circuit. In some specific embodiments, the interface position of the exhaust pipe 6 and the cooling liquid pipeline system 7 is located on a pipeline other than the third pipeline 73, the height of the interface position is h1, and the height of the highest point of the pipeline other than the third pipeline 73 in the cooling liquid pipeline system 7 is h2, wherein h1 and h2 satisfy h2-h1≤30mm. In some preferred embodiments, the interface position of the exhaust pipe 6 and the cooling liquid pipeline system 7 is located at the highest point of the pipeline other than the third pipeline 73. In some preferred embodiments, a valve is further provided on the exhaust pipe 6, and the proportion of gas and liquid in the exhaust pipe 6 is controlled by adjusting the opening degree of the valve, so that the liquid level height of the cooling liquid in the expansion tank 1 continuously decreases during the exhaust stage. In some preferred embodiments, a second exhaust pipe 61 is further included, the first port of the second exhaust pipe 61 is connected to the exhaust pipe 6, and the second port is connected to the cooling liquid pipeline system 7, so that the gas in the cooling liquid circuit can be discharged more quickly through the multiple exhaust pipelines.

[0082] Further, as shown in Figures 10-13 the application also optimizes the structure of the expansion tank 1, adopts an upper and lower separated expansion tank structure, and adjusts the cooling liquid compensation and gas pressure of the upper tank through the lower tank. In addition, a water injection port is provided to inject cooling liquid into the cooling liquid pipeline system through gravitational potential, which is more convenient than the conventional operation of injecting cooling liquid through a liquid injection water pump. The liquid injection operation can be completed without an additional liquid injection water pump, and the problem of pipeline air retention caused by too fast liquid injection of the liquid injection water pump is also avoided.

[0083] In some embodiments, the expansion tank 1 comprises a shell, which is internally divided into an upper water chamber 1-11 and a lower water chamber 1-12, the upper water chamber 1-11 is located above the lower water chamber 1-12, and the two water chambers are separated by a partition. The outer side of the upper part and the lower part of the shell are respectively provided with an exhaust pipe joint 1-3 and a liquid supplement pipe joint 1-4, one end of the exhaust pipe joint 1-3 is connected with the exhaust pipe 6, and the other end is connected with the upper end inside the upper water chamber 1-11; one end of the liquid supplement pipe joint 1-4 is connected with the liquid supplement pipe 5, and the other end is connected with the expansion tank liquid supplement pipe 51, the pipe opening of the expansion tank liquid supplement pipe 51 penetrates through the inside of the lower water chamber 1-12 and is connected with the lower end inside the upper water chamber 1-11, when the cooling liquid in the cooling liquid pipeline system 7 is insufficient, the cooling liquid in the upper water chamber 1-11 flows to the cooling liquid pipeline system 7 for liquid supplement through the expansion tank liquid supplement pipe 51 and the liquid supplement pipe 5 in turn.

[0084] The inside of the expansion tank 1 is also provided with a vertical expansion tank exhaust pipe 1-8, the upper water chamber 1-11 and the lower water chamber 1-12 are connected through the expansion tank exhaust pipe 1-8; the shell at the position corresponding to the upper end port of the expansion tank exhaust pipe 1-8 is upwardly protruded to form an upper gas collection area 1-7, the upper end port of the expansion tank exhaust pipe 1-8 is connected with the upper gas collection area 1-7, that is, the plane where the upper end port of the expansion tank exhaust pipe 1-8 is located is lower than the top end surface of the shell at the position of the upper gas collection area 1-7, but not lower than the top end surface of the shell at other positions except the upper gas collection area 1-7, so that the gas in the upper water chamber 1-11 in the working state can be gathered in the upper gas collection area 1-7 and enter the lower water chamber 1-12 through the expansion tank exhaust pipe 1-8; preferably, the bottom of the shell at the position corresponding to the lower end port of the expansion tank exhaust pipe 1-8 is downwardly protruded to form a lower gas collection area, and the lower end port of the expansion tank exhaust pipe 1-8 is connected with the lower gas collection area.

[0085] The expansion tank 1 also comprises a pressure relief valve 1-6, which is arranged at the top of the lower water chamber 1-12, the pressure relief valve 1-6 is automatically opened and closed according to the gas pressure in the lower water chamber 1-12, and when the gas pressure in the lower water chamber 1-12 is too large, the pressure relief valve 1-6 is automatically opened to discharge the gas in the lower water chamber 1-12 for pressure relief.

[0086] The expansion tank 1 also comprises a liquid level measuring instrument 1-9 and a liquid level observation window 1-5, the liquid level measuring instrument 1-9 is arranged inside the lower water chamber 1-12, and the liquid level observation window 1-5 is arranged outside the lower water chamber 1-12 at the position corresponding to the liquid level measuring instrument 1-9, for monitoring and observing the position of the cooling liquid in the lower water chamber 1-12.

[0087] In some preferred embodiments, the top of the upper water chamber 1-11 is further provided with a water injection port 1-2, which is located at the highest point of the entire cooling liquid circuit, so that the cooling liquid injected through the water injection port 1-2 can flow to various parts of the system by gravitational potential energy; specifically, before work, the entire cooling liquid circuit is filled with cooling liquid by injecting cooling liquid from the water injection port 1-2, which is more convenient to operate than the conventional way of injecting cooling liquid by water pump, and the liquid injection operation can be completed without additional water pump, and the problem of pipeline air retention caused by too fast water pump injection is also avoided; specifically, the water injection port 1-2 includes a first water injection port 1-21 and a second water injection port 1-22, wherein the first water injection port 1-21 is directly connected to the lower water chamber 1-12 through a pipeline, and the second water injection port 1-22 is in communication with the upper water chamber 1-11.

[0088] In some preferred embodiments, the structure of the electric heater module 10 is further optimized. As described above, in order to meet the size requirements of the installation layout of the thermal management system and save space, the electric heater module 10 is connected in series in the first cooling liquid circuit, but this also brings the following problems: when selecting a suitable type of electric heater according to the heating heat required by the cooling liquid circuit, since the pipe diameter of the inlet and outlet liquid pipes in the standard specification heater is fixed, it often cannot be the same as the pipe diameter of the cooling liquid pipeline system, especially when the pipe diameter of the heater pipeline is smaller than the pipe diameter of the cooling liquid pipeline system, which will increase the resistance at the connection and affect the cooling liquid circulation efficiency; if the pipe diameter of the inlet and outlet liquid pipes of the electric heater is set to be the same as the pipe diameter of the cooling liquid pipeline system, it needs to be customized separately, which undoubtedly increases the cost; based on this problem, the structure of the electric heater module 10 is further optimized, and by setting a bypass pipe outside the electric heater shell and optimizing the design of the electric heater parameters and the bypass pipe diameter parameters, the cooling liquid circulation efficiency of the cooling liquid circuit is not affected, and the energy consumption of the electric heater is saved.

[0089] Figure 14 The specific structure of the electric heater module 10 in some specific embodiments of the application is shown, which includes a first electric heater device 101 and an external pipeline 102, wherein the electric heater device is a commercially available standard specification electric heater device, the first electric heater device 101 internally accommodates a heating element, a power control system and a pipeline, the first electric heater device 101 is provided with an inlet liquid pipe 1011 and an outlet liquid pipe 1012, and the inlet liquid pipe 1011 and the outlet liquid pipe 1012 form a communicating fluid passage with the pipeline inside the first electric heater device 101, so that the cooling liquid flows into the inlet liquid pipe 1011 for heating and flows out of the outlet liquid pipe 1012 during work.

[0090] The external pipeline 102 is located outside the first electric heater device 101, and includes a bypass pipe 1021 for connecting the inlet pipe 1011 and the outlet pipe 1012. In some specific embodiments, the bypass pipe 1021 can be a straight pipe or a bent pipe, that is, its pipeline layout can be set according to the requirements of a specific application, and there is no specific limitation thereto. In some specific embodiments, in order to facilitate the connection of the pipeline, a first tee fitting 1022 is provided on the inlet pipe 1011 and a second tee fitting 1023 is provided on the outlet pipe 1012. The bypass pipe 1021 is connected between the first tee fitting 1022 and the second tee fitting 1023. One port of the first tee fitting 1022 is connected to the port of the third pipeline 73, and one port of the second tee fitting 1023 is connected to the fourth pipeline 74.

[0091] In some preferred embodiments, the diameter of the coolant piping system 7 is 25-40 mm, the rated power of the first electric heater device 101 is 30-50 KW, the diameter of its inlet pipe 1011 and outlet pipe 1012 is 10-30 mm, and the diameter of the bypass pipe 1021 is less than 30 mm.

[0092] In some preferred embodiments, to accommodate the top-mounted enclosure space layout design while still meeting condensation requirements, this application further optimizes the arrangement of the fan 14 and the condenser 13, such as... Figure 15 As shown, the fan 14 is located in the middle of the second cavity, and there are two condensers 13, which are respectively placed on both sides of the fan 14 along the radial direction of the fan 14. An air inlet is provided on the top of the housing 1 corresponding to the condenser 13, and an air outlet is provided on the top of the housing 1 corresponding to the fan 14. Thus, air enters from both sides and exits from the middle in the direction indicated by the arrow in the figure. Furthermore, in order to meet sufficient air circulation and increase the contact area between the condenser tube and the air, the condenser 13 is set at an angle relative to the axis of the fan 14.

[0093] In some specific embodiments, the control system further includes several temperature sensors to monitor the temperature at different locations and thereby adjust the operating mode of the thermal management system; specifically, the temperature sensors include an ambient temperature sensor and a pipeline sensor. The ambient temperature sensor is located at the air inlet of the second cavity 100-2, and the pipeline temperature sensors are respectively located at the outlet pipeline of the condenser 13, the outlet pipeline of the plate heat exchanger 2, the outlet pipeline of the electric heater module 10, and the inlet pipeline of the plate heat exchanger 2.

[0094] In some specific embodiments, the control system further includes several pressure sensors for checking system pressure to ensure the overall performance of the thermal management system.

[0095] The specific implementation ways of the present application are described in detail above, and for the person skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also belong to the protection scope of the claims of the present application.

Claims

1. A thermal management system for locomotive power batteries, characterized in that, Includes a housing and a water pump (3), plate heat exchanger (2), compressor (8), gas-liquid separator (9), electric heater module (10), condenser (13), fan (14), radiator (15), expansion valve (17), piping system for connecting the various components, valve assembly on the piping system for controlling its on / off state, and control system. The piping system includes a coolant piping system and a refrigerant piping system. The water pump (3), the coolant side of the plate heat exchanger (2), and the electric heater module (10) are connected in series through the coolant piping system to form a first coolant circuit. The water pump (3), the radiator (15), and the electric heater module (10) are connected in series through the coolant piping system to form a second coolant circuit. The refrigerant side of the plate heat exchanger (2), the gas-liquid separator (9), the compressor (8), the condenser (13), and the expansion valve (17) are connected in series through the refrigerant piping system to form a refrigerant circuit. The radiator (15) and the fan (14) form a first air circuit. The condenser (13) and the fan (14) form a second air circuit. Each circuit shares one or more components and piping. The control system switches between three modes of the thermal management system: cooling mode, air cooling mode, and heating mode, by controlling the operation of each device and the on / off state of each circuit. The coolant piping system (7) includes a third pipe (73) for connecting the outlet of the water pump (3) and the inlet of the electric heater module (10), and the third pipe (73) is positioned higher than the other pipes in the coolant piping system (7); The piping system also includes a third coolant branch, which includes an expansion tank (1), a replenishment pipe (5) and an exhaust pipe (6). The expansion tank (1) is connected in parallel to the coolant pipeline shared by the first coolant circuit and the second coolant circuit through the replenishment pipe (5) and the exhaust pipe (6) for venting and replenishing the coolant circuit. One end of the replenishing pipe (5) and the exhaust pipe (6) are both connected to the expansion tank (1), and the other end is connected to the coolant pipeline shared by the first coolant circuit and the second coolant circuit. The interface between the exhaust pipe (6) and the coolant pipeline system (7) is located on a pipeline other than the third pipeline (73). The interface position is set so that the coolant level in the expansion tank (1) continues to decrease during the exhaust phase of the coolant circuit.

2. The thermal management system for locomotive power batteries according to claim 1, characterized in that, When in cooling mode, the first coolant circuit, refrigerant circuit, and second air circuit are connected, and the water pump (3), plate heat exchanger (2), gas-liquid separator (9), compressor (8), condenser (13), fan (14), and expansion valve (17) are working; when in air-cooling mode, the second coolant circuit and the first air circuit are connected, and the water pump (3), radiator (15), and fan (14) are working; when in heating mode, the first coolant circuit and the second coolant circuit are connected, and the water pump (3) and electric heater module (10) are working.

3. The thermal management system for locomotive power batteries according to claim 2, characterized in that, The control system determines the switching between the three modes—cooling mode, air-cooling mode, and heating mode—through the following steps: S1, obtain the ambient temperature and the temperature of the power battery (4); S2, determine whether the ambient temperature is greater than the first preset temperature. If yes, then enter cooling mode; otherwise, proceed to step S3. S3, determine whether the ambient temperature is greater than the second preset temperature. If so, then enter air-cooling mode; otherwise, proceed to step S4. S4, determine whether the temperature of the power battery (4) is greater than the third preset temperature. If not, then enter heating mode.

4. The thermal management system for locomotive power batteries according to claim 3, characterized in that, The cooling modes also include a first-level cooling mode, a second-level cooling mode, a third-level cooling mode, a fourth-level cooling mode, and a fifth-level cooling mode, which can be selected using the following methods: Step 1: Obtain the average temperature of the coolant in the first coolant circuit. ; Step 2, by analyzing the average temperature obtained in Step 1 With the preset target coolant temperature And thus select different cooling modes: when Select the first-level cooling mode; when Select the second-stage cooling mode; when Select the three-level cooling mode; when Select the fourth-level cooling mode; when Select the fifth-level cooling mode.

5. The thermal management system for locomotive power batteries according to claim 4, characterized in that, The control system includes a frequency converter (12) for frequency conversion control of the compressor (8) to achieve switching between different refrigeration modes.

6. The thermal management system for locomotive power batteries according to claim 1, characterized in that, The coolant piping system (7) further includes a first pipe (71) for connecting the outlet of the power battery (4) end pipe and the inlet of the plate heat exchanger (2), a second pipe (72) for connecting the outlet of the plate heat exchanger (2) and the inlet of the water pump (3), a fourth pipe (74) for connecting the outlet of the electric heater module (10) and the inlet of the power battery (4) end pipe, a fifth pipe (75) for connecting the first pipe (71) and the inlet of the radiator (15), and a sixth pipe (76) for connecting the outlet of the radiator (15) and the inlet of the water pump (3).

7. The thermal management system for locomotive power batteries according to claim 1, characterized in that, The electric heater module (10) includes a first electric heater device (101) and a bypass pipe (1021) disposed outside the first electric heater device (101). The first electric heater device (101) is provided with an inlet pipe (1011) and an outlet pipe (1012). The bypass pipe (1021) is used to connect the inlet pipe (1011) and the outlet pipe (1012).

8. The thermal management system for locomotive power batteries according to claim 7, characterized in that, The rated power of the first electric heater device (101) is 30~50 KW, the diameter of the inlet pipe (1011) and the outlet pipe (1012) is 10~30 mm, and the diameter of the bypass pipe (1021) is less than 30 mm.

9. The thermal management system for locomotive power batteries according to claim 8, characterized in that, The interior of the housing is divided into two independent chambers: a first chamber and a second chamber. The first chamber contains a plate heat exchanger (2), a water pump (3), a compressor (8), and a gas-liquid separator (9). The second chamber contains a condenser (13), a fan (14), and a radiator (15). The fan (14) is located in the middle of the second chamber. The condenser (13) is arranged on both sides of the fan (14) along the radial direction of the fan (14). The condenser (13) is arranged obliquely relative to the axis of the fan (14).

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