Thermal management system for locomotive power battery

Abstract

The invention relates to the technical field of rail transit heat exchange, in particular to a heat management system for a locomotive power battery. According to the overhead heat management system, the space at the top of a locomotive can be fully utilized, and the occupation of the internal space of the locomotive is reduced; the cooling liquid loop, the refrigerant loop, the air loop and the control system are integrated in the thermal management system, and the three working modes including the air cooling mode, the refrigeration mode and the heating mode can be switched according to the external environment temperature, the power battery temperature and the preset temperature threshold value, so that the power battery works within the proper temperature range; according to the heat management device, the structures of key components such as all components, pipeline position arrangement, an expansion water tank and an electric heater module are further optimized, so that the specific problems such as exhaust and rainfall resistance of a cooling liquid loop are solved, and the heat management of the locomotive power battery can be more efficiently achieved with low cost.

Description

Technical Field

[0001] The present application relates to the technical field of heat exchange in rail transit, and in particular to a thermal management system for locomotive power batteries. Background Art

[0002] As the core energy source of locomotives, the performance of power batteries directly affects the overall performance and cruising range of locomotives. However, power batteries generate a lot of heat during the charging and discharging process. If the heat cannot be effectively managed, the battery temperature will rise, which will in turn affect the safety, cycle life and performance of the battery. The locomotive power battery thermal management system is a key system to ensure that the power battery maintains a suitable operating temperature in a complex operating environment, improve battery performance and service life, and is crucial to maintaining the power battery within a suitable operating temperature range.

[0003] Since the ambient temperature of a power locomotive is usually in the range of -40°C to +40°C, in order to maintain the power battery in an appropriate operating temperature range, it is necessary not only to cool it but also to heat it. Most of the existing technologies use multiple independent systems to achieve this separately, which cannot be centrally managed and arranged. At the same time, multiple independent systems have multiple compressors, condensers, fans, etc., which also increases the cost. Therefore, a thermal management system for locomotive power batteries is needed to solve the above-mentioned problems. Summary of the invention

[0004] The purpose of this application is to provide a thermal management system for a locomotive power battery.

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

[0006] A thermal management system for a 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 components, a valve assembly and a control system arranged on the pipeline system for controlling the on-off thereof; wherein the pipeline system comprises a coolant pipeline system and a refrigerant pipeline system, the water pump, the coolant side of the plate heat exchanger, and the electric heater module are connected in series through the coolant pipeline system to form a first coolant loop; the water pump, the radiator , the electric heater modules are connected in series through the coolant piping system to form a second coolant 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 piping 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 the three modes of cooling, air cooling and heating of the thermal management system by controlling the operation of each device and the on and off of each circuit.

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

[0008] Furthermore, the control system determines the switching of the three modes of cooling mode, air cooling mode and heating mode through 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 the 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 the 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 not, entering a heating mode.

[0013] Furthermore, the refrigeration mode also includes a primary refrigeration mode, a secondary refrigeration mode, a tertiary refrigeration mode, a quaternary refrigeration mode and a quintuple refrigeration mode, which are selected by the following method:

[0014] Step 1: Obtain the average temperature T of the coolant in the first coolant circuit im ;

[0015] Step 2: The average temperature T obtained in step 1 im The preset coolant target temperature T ic Compare and choose different cooling modes:

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

[0017] When T ic +0.8>T im ≥T ic +0.5, select the secondary cooling mode;

[0018] When T ic +1>T im ≥T ic +0.8, select the three-stage cooling mode;

[0019] When T ic +1.4>T im ≥T ic When +1, select the four-level cooling mode;

[0020] When T im ≥T ic +1.4, select the five-level cooling mode.

[0021] Furthermore, the control system includes a frequency converter for performing frequency conversion control on the compressor to achieve switching between different refrigeration modes.

[0022] Furthermore, the coolant piping system includes a first pipeline for connecting the power battery end pipeline outlet and the plate heat exchanger inlet, a second pipeline for connecting the plate heat exchanger outlet and the water pump inlet, a third pipeline for connecting the water pump outlet and the electric heater module inlet, a fourth pipeline for connecting the electric heater module outlet and the power battery end pipeline inlet, a fifth pipeline for connecting the first pipeline and the radiator inlet, and a sixth pipeline for connecting the radiator outlet and the water pump inlet; the third pipeline is positioned higher than other pipelines in the coolant piping system.

[0023] Furthermore, it also includes a third coolant branch, which includes an expansion water tank, a replenishing pipe and an exhaust pipe. The expansion water tank is connected in parallel to the coolant pipeline shared by the first coolant circuit and the second coolant circuit through the replenishing pipe and the exhaust pipe, and is used to vent and replenish the coolant circuit.

[0024] Furthermore, one end of the replenishing pipe and the exhaust pipe are connected to the expansion water tank, and the other end are connected to the coolant pipeline shared by the first coolant circuit and the second coolant circuit. The interface position of the exhaust pipe and the coolant pipeline is set so that the liquid level of the coolant in the expansion water tank continues to decrease when the coolant circuit is in the exhaust stage.

[0025] Furthermore, the electric heater module includes a first electric heater device and a bypass pipe arranged outside the first electric heater device, the first electric heater device is provided with a liquid inlet pipe and a liquid outlet pipe, and the bypass pipe is used to connect the liquid inlet pipe and the liquid outlet pipe.

[0026] Furthermore, the rated power of the first electric heater device is 30-50 kW, the diameters of the liquid inlet pipe and the liquid outlet pipe are 10-30 mm, and the diameter of the bypass pipe is less than 30 mm.

[0027] Furthermore, the interior of the box is divided into two independent first cavities and a second cavity, wherein a plate heat exchanger, a water pump, a compressor, and a gas-liquid separator are arranged in the first cavity, and a condenser, a fan, and a radiator are arranged in the second cavity; the fan is placed in the middle of the second cavity, and 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 thermal management system for a locomotive power battery provided by the embodiments of the present application has at least the following beneficial effects:

[0029] The present application provides a roof-mounted thermal management system that can make full use of the space on the top of a locomotive while reducing the occupancy of the interior space of the locomotive; the thermal management system of the present application integrates a coolant circuit, a refrigerant circuit, an air circuit and a control system, and can switch between three operating modes, namely, air cooling mode, refrigeration mode and heating mode, according to the external ambient temperature, the power battery temperature and a preset temperature threshold, so that the power battery can operate within an appropriate temperature range; the present application further optimizes the structures of key components such as various components and pipeline position layout, expansion water tank and electric heater module, so as to solve specific problems such as exhaust and water resistance reduction of the coolant circuit, so that the system can achieve thermal management of locomotive power batteries more efficiently and at a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the overall structure of the thermal management system of an embodiment of the present application;

[0031] Figure 2 A schematic diagram of the internal device layout of a thermal management system according to an embodiment of the present application;

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

[0033] Figure 4 A schematic diagram of the internal structure of the second cavity of the thermal management system of an embodiment of the present application;

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

[0035] Figure 5b A schematic diagram of the cooling mode principle of the thermal management system of an embodiment of the present application;

[0036] Figure 5c A schematic diagram of the heating mode principle of the thermal management system of an embodiment of the present application;

[0037] Figure 6 A flow chart of a control method of a thermal management system according to an embodiment of the present application;

[0038] Figure 7 A schematic diagram of a coolant piping system according to an embodiment of the present application;

[0039] Figure 8 This is a schematic diagram of a specific structure of a coolant piping system according to an embodiment of the present application;

[0040] Fig. 9 A schematic diagram showing a specific structure of a cooling liquid pipeline system according to an embodiment of the present application from another angle;

[0041] Fig.10 This is a schematic diagram of the overall structure of the expansion water tank in the embodiment of the present application;

[0042] Fig.11 A top view of the expansion water tank in the embodiment of the present application;

[0043] Fig.12 for Fig.11 Middle AA section view;

[0044] Fig.13 For the exhaust stage Fig.11 Middle BB section;

[0045] Fig.14 Schematic diagram of the overall structure of the electric heater module in the embodiment of the present application;

[0046] Fig.15 This is a cross-sectional schematic diagram of the second cavity in the embodiment of the present application;

[0047] Numbers in the figure

[0048] Box body 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 supply pipe joint 1-4, liquid level observation window 1-5, pressure relief valve 1-6, upper gas collecting 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 supply pipe 5, expansion water tank liquid supply pipe 51, exhaust pipe 6, second exhaust pipe 61, coolant Pipe 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, inverter 12, condenser 13, fan 14, radiator 15, electric three-way valve 16, expansion valve 17; DETAILED DESCRIPTION

[0049] Hereinafter, the present application will be further described based on preferred embodiments with reference to the accompanying drawings.

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

[0051] Singular words also include plural meanings, and vice versa. In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the products of the embodiments of the present application are usually placed when used, it is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the present application, in order to distinguish different units, the words first, second, etc. are used in this specification, but these are not limited by the order of manufacture, nor can they be understood as indicating or implying relative importance, and their names may be different in the detailed description and claims of the present application.

[0052] The vocabulary in this specification is used to illustrate the embodiments of the present application, but is not intended to limit the present application. It should also be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, an indirect connection through an intermediate medium, or a connection between the two elements. For those skilled in the art, the specific meanings of the above terms in this application can be specifically understood.

[0053] The present application provides a thermal management system for a locomotive power battery 4, which is installed on the top of the locomotive and performs thermal management such as cooling and heating on the locomotive power battery 4 arranged below it so that the power battery 4 works within 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 multiple devices, systems, etc. need to be integrated in a limited space, which undoubtedly puts high requirements on the installation and arrangement of each system and device.

[0054] The following is a detailed description of the thermal management system provided by some embodiments of the present application. Figures 1 to 4It can be seen that it includes a box body 100 and devices contained in the box body 100, pipelines for connecting the devices, valve components arranged on the pipelines for controlling the on-off of the pipelines, and a control system; specifically, the interior of the box body is divided into two independent first cavities 100-1 and second cavities 100-2, wherein the first cavity 100-1 is provided 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 provided with a frequency converter 12, a condenser 13, a fan 14 and a radiator 15;

[0055] Specifically, the water pump 3, the coolant side of the plate heat exchanger 2, and the electric heater module 10 are connected in series through pipelines and constitute a first coolant 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 coolant 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 the three modes of cooling mode, air cooling mode and heating mode of the thermal management system by controlling the operation of each device and the on-off of each circuit, which includes an electric control box 11 and a frequency converter 12, and the frequency converter 12 can further realize the variable frequency control of the compressor 8, thereby realizing the switching of different cooling modes, and the frequency conversion control can reduce the number of starts and stops of the compressor 8 and extend the service life.

[0056] In some specific embodiments, the switching between the first coolant circuit and the second coolant circuit is achieved by an electric three-way valve 16 placed on the pipeline, wherein the first interface of the electric three-way valve 16 is connected to the radiator 15, the second interface is connected to the plate heat exchanger 2, and the third interface is connected to the water pump 3 or the power battery 4.

[0057] The following combination Figure 5a , Figure 5b and Figure 5cThe schematic diagram of each working mode is used for specific introduction. When in the cooling mode, the first coolant circuit, the refrigerant circuit and the second air circuit are connected, and the water pump 3, the plate heat exchanger 2, the gas-liquid separator 9, the compressor 8, the condenser 13, the fan 14 and the expansion valve 17 are working; specifically, the high-temperature coolant in the cooling pipeline at the end of the power battery 4 is pumped to the coolant side of the plate heat exchanger 2 by the action of the water pump 3, and after completing the convection heat exchange process with the refrigerant side of the plate heat exchanger 2, the low-temperature coolant flows back to the cooling pipeline at the end of the power battery 4 to cool the power battery 4; and the refrigerant on the refrigerant side of the plate heat exchanger 2 absorbs the heat from the coolant and becomes high-temperature and high-pressure steam. After passing through the gas-liquid separator 9, it enters the compressor 8 for compression to become high-temperature and high-pressure steam, and then 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 is obtained and flows back to the plate heat exchanger 2 for circulation.

[0058] When in air cooling mode, the second coolant circuit is connected to the first air circuit, and the water pump 3, the radiator 15, and the fan 14 are in operation; specifically, at this time, the high-temperature coolant at the power battery 4 end is pumped to the radiator 15 by the water pump 3, and the heat is dissipated through the first air circuit. After releasing the heat, the low-temperature coolant flows back to the cooling pipeline at the power battery 4 end 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 pipeline at the power battery 4 end is pumped to the electric heater module 10 for heating under the action of the water pump 3, and the heated high-temperature coolant flows back to the power battery 4 end to heat it.

[0060] Furthermore, if Figure 6 As shown, the control system can switch between different modes according to the external environment temperature, the temperature of the power battery 4, and the preset temperature threshold through the following steps:

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

[0062] S2, determining whether the ambient temperature is greater than the first preset temperature T1, if yes, entering the cooling mode; if no, proceeding to step S3;

[0063] S3, determining whether the ambient temperature is greater than the second preset temperature T2, if yes, entering the air cooling mode; if no, proceeding to step S4;

[0064] S4, determining whether the temperature of the power battery 4 is greater than a third preset temperature T3, if not, entering a heating mode;

[0065] Furthermore, the cooling mode further comprises the following steps:

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

[0067] Step 2: The average temperature T obtained in step 1 im The preset coolant target temperature T ic Compare and adjust the power of compressor 8 to enter different refrigeration modes:

[0068] When T ic +0.5>T im ≥T ic When the inverter 12 is used, the power of the compressor 8 is adjusted to the first power, and the first-level cooling mode is entered;

[0069] When T ic +0.8>T im ≥T ic +0.5, the inverter 12 is used to adjust the power of the compressor 8 to the second power, and the secondary cooling mode is entered;

[0070] When T ic +1>T im ≥T ic +0.8, the inverter 12 is used to adjust the power of the compressor 8 to the third power, and the third-level cooling mode is entered;

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

[0072] When T im ≥T ic +1.4, the inverter 12 is used to adjust the power of the compressor 8 to the fifth power, entering the fifth-level refrigeration mode;

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

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

[0075] In some preferred embodiments, the thermal management system further includes a third coolant branch, and the third coolant branch includes an expansion water tank 1, which is connected in parallel with the first coolant circuit and the second coolant circuit through pipelines, and is used for replenishing and exhausting each coolant circuit.

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

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

[0078] In some specific 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 achieved by adjusting the electric three-way valve 16.

[0079] In some specific embodiments, the third coolant branch includes an expansion water tank 1, a refill pipe 5 and an exhaust pipe 6. The expansion water tank 1 is connected in parallel with the first coolant circuit and the second coolant circuit through the exhaust pipe 6 and the refill pipe 5. Specifically, one end of the refill pipe 5 and the exhaust pipe 6 are 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 water tank 1. When in use, the gas in the coolant circuit enters the expansion water tank 1 through the exhaust pipe 6 and is discharged to the atmosphere by the expansion water tank 1. When the coolant in the coolant circuit is insufficient, the coolant pre-stored in the expansion water tank 1 is replenished into the coolant circuit through the refill pipe 5, thereby realizing the refilling and exhaust of the coolant circuit.

[0080] However, since the gas generally gathers at a high position in the pipeline due to its light weight during exhaust, the conventional operation in the field is to connect one end of the exhaust pipe 6 to the highest position of the coolant circuit, that is, the highest point of the third pipeline 73. However, this point is located at the outlet of the water pump 3, and the excessive pressure causes too much coolant to be diverted through the exhaust pipe 6 and flow into the expansion water tank 1. After flowing into the expansion water tank 1, this part of the coolant will be stored in the expansion water tank 1 and will not flow back into the coolant circuit, thus causing the water pump to be sucked empty.

[0081] Based on the above-mentioned water pump cavitation problem, the applicant has found that when the exhaust pipe 6 is connected to a specific pipeline position in the coolant circuit, the above-mentioned water pump cavitation phenomenon can be avoided on the one hand, and the exhaust effect of the circuit can be guaranteed on the other hand; specifically, when the exhaust pipe 6 is connected to a specific pipeline position in the coolant circuit, the coolant level in the expansion water tank 1 can be continuously reduced during the exhaust stage of the coolant circuit; in some specific embodiments, the interface position of the exhaust pipe 6 and the coolant piping system 7 is located on the pipeline except the third pipeline 73, and the height of the interface position is h1, and the highest point height of the pipeline except the third pipeline 73 in the coolant piping system 7 is h2, where h1 and h2 satisfy h2-h1≤30mm; in some preferred embodiments, the interface position between the exhaust pipe 6 and the coolant pipeline system 7 is located at the highest point of the pipeline except the third pipeline 73; in some preferred embodiments, a valve is also provided on the exhaust pipe 6, and the ratio of gas to liquid in the exhaust pipe 6 is controlled by adjusting the valve opening, so that the liquid level of the coolant in the expansion water tank 1 continues to decrease during the exhaust stage; in some preferred embodiments, a second exhaust pipe 61 is further included, and a first port of the second exhaust pipe 61 is connected to the exhaust pipe 6, and a second port is connected to the coolant pipeline system 7. The gas in the coolant circuit can be discharged faster by setting multiple exhaust pipelines.

[0082] Furthermore, if Figure 10-13 As shown, the present application also optimizes the structure of the expansion water tank 1, adopts an upper and lower separated expansion water tank structure, and uses the lower water tank to compensate the upper water tank for coolant and adjust the gas pressure. In addition, a water injection port is provided to inject the coolant into the coolant pipeline system through gravitational potential energy. Compared with the conventional method of injecting coolant through an injection water pump, the operation is simpler and the injection operation can be completed without an additional injection water pump, and the problem of air suffocation in the pipeline caused by the injection water pump injecting too quickly can be avoided.

[0083] In some specific embodiments, the expansion water tank 1 includes a shell, the interior of which is 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. An exhaust pipe joint 1-3 and a liquid replenishing pipe joint 1-4 are respectively arranged on the upper and lower parts of the outer side of the shell, one end of the exhaust pipe joint 1-3 is connected to the exhaust pipe 6, and the other end is connected to the upper end of the upper water chamber 1-11; one end of the liquid replenishing pipe joint 1-4 is connected to the liquid replenishing pipe 5, and the other end is connected to the expansion water tank liquid replenishing pipe 51, the pipe mouth of the expansion water tank liquid replenishing pipe 51 passes through the lower water chamber 1-12 and is connected to the lower end of the upper water chamber 1-11. When the coolant in the coolant pipeline system 7 is insufficient, the coolant in the upper water chamber 1-11 flows to the coolant pipeline system 7 through the expansion water tank liquid replenishing pipe 51 and the liquid replenishing pipe 5 in turn for liquid replenishment.

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

[0085] The expansion water tank 1 also includes 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 automatically opens and closes according to the gas pressure in the lower water chamber 1-12. When the gas pressure in the lower water chamber 1-12 is too high, the pressure relief valve 1-6 automatically opens to discharge the gas in the lower water chamber 1-12 to relieve the pressure.

[0086] The expansion water tank 1 also includes 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 on the outside of the lower water chamber 1-12 corresponding to the position of the liquid level measuring instrument 1-9, and is used to monitor and observe the position of the coolant in the lower water chamber 1-12.

[0087] In some preferred embodiments, a water injection port 1-2 is further provided at the top of the upper water chamber 1-11, and the water injection port 1-2 is located at the highest point of the entire coolant circuit, so that the coolant injected through the water injection port 1-2 can flow into various places in the system better by virtue of gravitational potential energy; specifically, before work, the coolant is injected from the water injection port 1-2 to fill the entire coolant circuit with coolant, which is simpler to operate than the conventional method of injecting coolant through a water pump, and the injection operation can be completed without an additional water pump, and the problem of pipe suffocation 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 connected to the upper water chamber 1-11.

[0088] In some preferred embodiments, the present application also optimizes the structure of the electric heater module 10. As mentioned above, in order to meet the size requirements of the thermal management system installation layout and save space, the present application connects the electric heater module 10 in series in the first coolant loop, but this also brings the following problems: when selecting an electric heater of a suitable model according to the heating heat required by the coolant loop, since the diameters of the inlet and outlet pipes in the standard specification heater are fixed, they are often not the same as the diameters of the coolant piping system, especially when the diameter of the heater pipe is smaller than the diameter of the coolant piping system, the resistance at the connection will increase, thereby affecting the coolant circulation efficiency; and if the diameters of the inlet and outlet pipes of the electric heater are set to be the same as the diameter of the coolant piping system, they need to be customized separately, which undoubtedly increases a lot of costs; based on this problem, the present application further optimizes the structure of the electric heater module 10, by setting a bypass pipe outside the electric heater housing and optimizing the electric heater parameters and bypass pipe diameter parameters, so that the coolant circulation efficiency of the coolant loop is not affected while also saving the energy consumption of the electric heater.

[0089] Fig.14 The specific structure of the electric heater module 10 in some specific embodiments of the present 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 electric heater device, the first electric heater device 101 internally accommodates a heating element, a power control system and a pipeline, and the first electric heater device 101 is provided with a liquid inlet pipe 1011 and a liquid outlet pipe 1012, the liquid inlet pipe 1011 and the liquid outlet pipe 1012 together with the pipeline inside the first electric heater device 101 form a connected fluid channel, so that during operation, the coolant flows in from the liquid inlet pipe 1011 for heating and flows out from the liquid outlet pipe 1012.

[0090] The external pipeline 102 is arranged outside the first electric heater device 101, and includes a bypass pipe 1021 for connecting the liquid inlet pipe 1011 and the liquid outlet pipe 1012; in some specific embodiments, the bypass pipe 1021 can be a straight pipe or a curved pipe, that is, its pipeline layout can be set according to the requirements of a specific use occasion, and no specific limitation is made to this; in some specific embodiments, in order to facilitate the connection of the pipelines, a first three-way pipe fitting 1022 is further provided on the liquid inlet pipe 1011, and a second three-way pipe fitting 1023 is provided on the liquid outlet pipe 1012, wherein the bypass pipe 1021 is connected between the first three-way pipe fitting 1022 and the second three-way pipe fitting 1023, one port of the first three-way pipe fitting 1022 is connected to the port of the third pipeline 73, and one port of the second three-way pipe 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 diameters of the liquid inlet pipe 1011 and the liquid outlet pipe 1012 are 10-30 mm, and the diameter of the bypass pipe 1021 is less than 30 mm.

[0092] In some preferred embodiments, in order to adapt to the top-mounted box space layout design and meet the condensation effect, the present application further optimizes the layout of the fan 14 and the condenser 13, such as Fig.15 As shown, the fan 14 is placed in the middle of the second cavity, and there are two condensers 13, which are placed on both sides of the fan 14 along the radial direction of the fan 14, and an air inlet is provided at the top of the box body 1 corresponding to the condenser 13, and an air outlet is provided at the top of the box body 1 corresponding to the fan 14. Therefore, air enters from both sides along the direction indicated by the arrow in the figure and exits from the middle; further, in order to meet sufficient air circulation and increase the contact area between the condenser tube and the air, the condenser 13 is obliquely arranged relative to the axis of the fan 14.

[0093] In some specific embodiments, the control system also includes a plurality of temperature sensors to monitor the temperatures 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 arranged at the air inlet of the second cavity 100-2, and the pipeline temperature sensors are respectively arranged 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 a plurality of pressure sensors for checking the system pressure to ensure the overall performance of the thermal management system.

[0095] The above is a detailed introduction to the specific implementation methods of the present application. For those skilled in the art, several improvements and modifications may be made to the present application without departing from the principles of the present application. These improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A thermal management system for a locomotive power battery, characterized in that: The invention comprises a box body and a water pump (3) disposed inside the box body, a plate heat exchanger (2), a compressor (8), a gas-liquid separator (9), an electric heater module (10), a condenser (13), a fan (14), a radiator (15), an expansion valve (17), a pipeline system for connecting various components, a valve assembly and a control system arranged on the pipeline system for controlling the on and off of the pipeline system; The piping system comprises 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; and one or more devices and pipelines are shared between the various circuits; The control system realizes the switching of the three modes of the thermal management system, namely, the cooling mode, the air cooling mode and the heating mode, by controlling the operation of each device and the on-off of each circuit.

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

3. The thermal management system for a locomotive power battery according to claim 2, characterized in that: The control system determines the switching of the three modes of cooling mode, air cooling mode and heating mode through the following steps: S1, obtaining the ambient temperature and the temperature of the power battery (4); S2, determining whether the ambient temperature is greater than the first preset temperature T1, if yes, entering the cooling mode; if no, proceeding to step S3; S3, determining whether the ambient temperature is greater than the second preset temperature T2, if yes, entering the air cooling mode; if no, proceeding to step S4; S4, judging whether the temperature of the power battery (4) is greater than a third preset temperature T3, if not, entering a heating mode.

4. The thermal management system for a locomotive power battery according to claim 3, characterized in that: The refrigeration mode also includes a primary refrigeration mode, a secondary refrigeration mode, a tertiary refrigeration mode, a quaternary refrigeration mode and a quintuple refrigeration mode, which are selected by the following method: Step 1: Obtain the average temperature T of the coolant in the first coolant circuit im ; Step 2: The average temperature T obtained in step 1 im The preset coolant target temperature T ic Compare and choose different cooling modes: When T ic +0.5>T im ≥T ic When the cooling mode is on, select the first-level cooling mode; When T ic +0.8>T im ≥T ic +0.5, select the secondary cooling mode; When T ic +1>T im ≥T ic +0.8, select the three-stage cooling mode; When T ic +1.4>T im ≥T ic When +1, select the four-level cooling mode; When T im ≥T ic +1.4, select the five-level cooling mode.

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

6. The thermal management system for a locomotive power battery according to claim 1, characterized in that: The coolant pipeline system (7) comprises a first pipeline (71) for connecting the pipeline 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 (73) 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 pipeline at the power battery (4), a fifth pipeline (75) for connecting the first pipeline (71) and the liquid inlet of 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); the position of the third pipeline (73) is higher than other pipelines in the coolant pipeline system (7).

7. The thermal management system for a locomotive power battery according to claim 6, characterized in that: It also includes a third coolant branch, which includes an expansion water tank (1), a liquid replenishing pipe (5) and an exhaust pipe (6). The expansion water tank (1) is connected in parallel to the coolant pipeline shared by the first coolant circuit and the second coolant circuit through the liquid replenishing pipe (5) and the exhaust pipe (6), and is used to exhaust and replenish the coolant circuit.

8. The thermal management system for a locomotive power battery according to claim 7, characterized in that: One end of the liquid replenishment pipe (5) and the exhaust pipe (6) are both connected to the expansion water 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 position of the exhaust pipe (6) and the coolant pipeline is arranged so that when the coolant circuit is in the exhaust stage, the liquid level of the coolant in the expansion water tank (1) continues to decrease.

9. The thermal management system for a locomotive power battery according to claim 1, characterized in that: The electric heater module (10) comprises a first electric heater device (101) and a bypass pipe (1021) arranged outside the first electric heater device (101); the first electric heater device (101) is provided with a liquid inlet pipe (1011) and a liquid outlet pipe (1012); the bypass pipe (1021) is used to connect the liquid inlet pipe (1011) and the liquid outlet pipe (1012).

10. The thermal management system for a locomotive power battery according to claim 9, characterized in that: The rated power of the first electric heater device (101) is 30-50 kW, the diameters of the liquid inlet pipe (1011) and the liquid outlet pipe (1012) are 10-30 mm, and the diameter of the bypass pipe (1021) is less than 30 mm.

11. The thermal management system for a locomotive power battery according to claim 10, characterized in that: The interior of the box is divided into two mutually independent first cavities and second cavities, wherein a plate heat exchanger (2), a water pump (3), a compressor (8), and a gas-liquid separator (9) are arranged in the first cavity, and a condenser (13), a fan (14), and a radiator (15) are arranged in the second cavity; the fan (14) is placed in the middle of the second cavity, and the condenser (13) is arranged on both sides of the fan (14) along the radial direction of the fan (14), and the condenser (13) is arranged obliquely relative to the axis of the fan (14).

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