Cooling system and method for a traction battery of a new energy locomotive

Abstract

The application discloses a cooling system and method for a new energy locomotive power storage battery, which comprises a battery module, a water chiller unit, a cooling liquid circuit, a plate heat exchanger, a circulating pump and a thermal management controller; the water chiller unit comprises a compressor, a condenser, an expansion valve and an evaporator, and the evaporator is integrated with the plate heat exchanger; the thermal management controller is connected with a battery management module and controls the operation of the water chiller unit and the circulating pump according to a battery temperature signal; the cooling liquid circuit comprises a cooling liquid channel flowing through a battery cooling plate, and the cooling liquid exchanges heat with refrigerant in the plate heat exchanger. The application introduces an active refrigeration cycle based on the water chiller unit, realizes precise temperature control of the battery pack in an extreme environment, has strong cooling capacity and high efficiency, can ensure that the temperature difference in the battery pack is less than 2 DEG C, and is suitable for high-power fast charging, heavy-load climbing and other high-heat working conditions.

Description

Technical Field

[0001] This invention relates to the field of cooling technology for new energy locomotives and rolling stock in the rail transit industry, specifically to a cooling system and method for power batteries of new energy locomotives. Background Technology

[0002] With the global energy structure transformation and increasing environmental protection requirements, new energy locomotives, as a green mode of transportation, are being widely used in the rail transit sector. The core power source of new energy locomotives is a large-capacity power battery pack, which generates a significant amount of heat during charging and discharging. If this heat cannot be dissipated in time, it will lead to excessively high battery temperatures, affecting battery performance, lifespan, and safety, and in severe cases, may even cause safety accidents such as thermal runaway.

[0003] Traditional battery cooling technologies mainly include air cooling and conventional liquid cooling. Air cooling technology uses fans to force airflow to remove heat generated by the battery. It has a simple structure and low cost, but its heat dissipation capacity is limited. Air's thermal conductivity is much lower than that of liquids, resulting in low heat dissipation efficiency for air cooling systems. Furthermore, air cooling systems tend to cause uneven temperature distribution within the battery pack, with large temperature differences, affecting battery consistency and lifespan. Under high-heat conditions such as high-power fast charging and heavy-load hill climbing, the cooling effect of traditional air cooling technology often fails to meet requirements.

[0004] Conventional liquid cooling technology removes battery heat through coolant circulation, offering higher heat dissipation efficiency compared to air cooling. However, existing conventional liquid cooling systems typically rely on external cooling water sources or ambient air for cooling, making their cooling capacity highly susceptible to ambient temperature. In high-temperature environments, the coolant temperature is high, significantly reducing cooling effectiveness; under extreme high-temperature conditions, the coolant temperature may even exceed the battery's safe operating temperature, leading to system failure. Furthermore, conventional liquid cooling systems often lack precise temperature control capabilities, making it difficult to accurately regulate battery temperature.

[0005] The working environment of rail transit locomotives is special: (1) The locomotive operates under continuous high load conditions, and the battery pack needs to maintain high power output for a long time, resulting in large and continuous heat generation; (2) The locomotive vibrates violently during operation, which puts forward strict requirements on the mechanical structure stability of the cooling system; (3) The locomotive may operate in extreme environments of high temperature or low temperature, and the cooling system needs to have good environmental adaptability; (4) The locomotive space is compact, which imposes strict limitations on the volume and integration of the cooling system; (5) The locomotive maintenance conditions are limited, and the cooling system needs to have high reliability and easy maintenance characteristics.

[0006] In summary, traditional air-cooling and conventional liquid-cooling technologies have the following technical problems: (1) limited heat dissipation capacity, unable to meet the cooling requirements under high-power conditions; (2) poor environmental adaptability, with a significant decrease in cooling effect under high-temperature environments; (3) low temperature control accuracy, resulting in a large temperature difference within the battery pack; (4) insufficient vibration resistance, making it difficult to adapt to locomotive operating conditions; and (5) low system integration, large space occupation, and inconvenient deployment on locomotives. Therefore, there is an urgent need for a battery cooling system solution that is efficient, powerful, precise, and environmentally adaptable.

[0007] It should be noted that the above statements are only used to provide background information related to this application and do not necessarily constitute prior art. Summary of the Invention

[0008] The purpose of this invention is to provide a cooling system and method for power batteries of new energy locomotives, so as to solve the technical problems of insufficient cooling capacity, low temperature control accuracy, poor environmental adaptability and insufficient vibration resistance in the prior art.

[0009] To achieve the above objectives, this application provides the following technical solution: A cooling system for a power battery in a new energy locomotive, comprising: The battery module integrates a battery cooling plate and a coolant circuit; A circulation pump is provided in the coolant circuit to drive the coolant to circulate. A water chiller unit, comprising a compressor, a condenser, an expansion valve, and an evaporator; A plate heat exchanger is disposed between the cooling liquid circuit and the refrigerant circuit of the chiller unit; The battery management module includes a thermal management controller and a temperature sensor. The thermal management controller controls the operation of the chiller and the circulating pump based on the battery temperature signal from the temperature sensor. The evaporator and the plate heat exchanger are integrated.

[0010] Furthermore, the thermal management controller adopts a frequency conversion control strategy to adjust the operating frequency of the compressor according to the actual heat load of the battery.

[0011] Furthermore, the thermal management controller dynamically matches the actual thermal load of the battery by adjusting the rotational speed of the circulating pump and the opening degree of the expansion valve.

[0012] Furthermore, the chiller unit also includes a condenser fan, which is used to provide forced air cooling for the condenser.

[0013] Furthermore, the coolant is selected as an ethylene glycol-water solution.

[0014] Furthermore, the battery cooling plate is located at the bottom of the battery module and adopts a dual-channel design inside.

[0015] Furthermore, the cooling system also includes a heater connected to the battery module for preheating the battery in a low-temperature environment.

[0016] Furthermore, the chiller unit adopts a modular installation design, and the chiller unit mounting base is inlaid with rubber vibration damping blocks.

[0017] Furthermore, the coolant circuit also includes a pipe support, metal clamps, and a connecting flange. The pipe support is made of high-strength sheet metal, the metal clamps are used to fix the pipes, and the connecting flange is installed using a flange mounting method.

[0018] This invention also provides a cooling method for a power battery in a new energy locomotive, comprising the following steps: The battery management module monitors the battery temperature in real time. When the battery temperature exceeds the first preset threshold, it sends a cooling command request to the thermal management controller. After receiving a cooling command, the thermal management controller starts the circulation pump to drive the coolant to circulate in the coolant circuit, and at the same time starts the chiller unit to circulate the refrigerant in the refrigeration cycle circuit. The coolant flows through the battery cooling plate below the battery module, absorbing the heat generated by the battery. The heated coolant then enters the coolant side of the plate heat exchanger. In a plate heat exchanger, the heat of the coolant is absorbed by the low-temperature, low-pressure refrigerant. The cooled refrigerant is then evaporated into a low-temperature, low-pressure gaseous refrigerant and returned to the compressor. The thermal management controller receives real-time feedback on battery temperature and adjusts the operating frequency of the compressor and the speed of the circulation pump according to the temperature deviation to keep the battery temperature stable within the target temperature range. When the battery temperature drops to the second preset threshold, the thermal management controller controls the compressor to operate at a reduced frequency or enter an intermittent operation mode.

[0019] Compared with the prior art, the present invention has the following beneficial effects: This invention employs an active refrigeration cycle based on a chiller unit, achieving heat transfer through refrigerant phase change. The refrigerant boasts a high latent heat of vaporization and high heat exchange efficiency. Compared to traditional air cooling and conventional liquid cooling, this invention significantly enhances cooling capacity, making it particularly suitable for high-power fast charging, heavy-load hill climbing, and other high-heat-generating operating conditions. At an ambient temperature of 45°C, this invention can maintain the battery's operating temperature below 35°C.

[0020] This invention employs a variable frequency control strategy based on battery heat load prediction. By monitoring battery temperature in real time and dynamically adjusting compressor speed, circulating pump flow rate, and expansion valve opening, it can precisely control cooling power and achieve accurate battery temperature regulation. The dual-flow-channel battery cooling plate, combined with the efficient heat exchange of the plate heat exchanger, ensures a temperature difference within the battery pack of less than 2°C, extending battery life and improving battery consistency.

[0021] This invention utilizes a chiller unit to actively produce low-temperature coolant, ensuring cooling capacity independent of ambient temperature and maintaining good cooling performance even in high-temperature environments. The evaporator and plate heat exchanger are integrated, reducing external piping connections, minimizing heat loss, and improving system reliability. The chiller unit employs a modular design and is equipped with rubber vibration damping blocks, effectively buffering vibrations during locomotive operation and adapting to locomotive vibration conditions.

[0022] The chiller unit of the present invention can reverse the cycle to form a heat pump mode, or it can heat the battery in a low-temperature environment by integrating a heater to realize the battery preheating function, thereby expanding the temperature operating range of the system and improving the reliability of the system in extreme low-temperature environments.

[0023] This invention employs a highly integrated modular design, with all major components integrated within the chiller unit. External piping uses flange connections, facilitating overall disassembly and maintenance. Pipe supports and metal clamps in the coolant circuit utilize standard rail transit industry products, and O-rings are made of fluororubber, ensuring excellent sealing performance and long maintenance intervals.

[0024] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application, specific implementation methods of this application are given below. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0026] Figure 1 This is a schematic diagram of the principle of the cooling system for the power battery of the new energy locomotive of the present invention.

[0027] Figure 2 This is a schematic diagram of the pipeline installation structure in this invention.

[0028] Explanation of markings in the diagram: 1-Battery Management Module (BMS); 2-Temperature Sensor; 3-Thermal Management Controller; 4-Chiller Unit; 5-Compressor; 6-Condenser; 7-Expansion Valve; 8-Evaporator; 9-Plate Heat Exchanger; 10-Battery Module; 11-Circulation Pump; 12-Cooling Fan; 13-Heater; 14-Pipe Support; 15-Metal Clamp; 16-Connecting Flange; 17-O-ring Seal. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below.

[0030] The cooling system and method for power batteries of new energy locomotives provided in this invention are applicable to the thermal management of power batteries in new energy locomotives in the rail transit industry. The following detailed description is provided in conjunction with specific embodiments and accompanying drawings.

[0031] like Figure 1 As shown, the cooling system for the power battery of a new energy locomotive provided in this embodiment of the invention mainly includes a battery module 10, a chiller unit 4, a coolant circuit, a plate heat exchanger 9, a circulating pump 11, and a thermal management controller 3. The system cools the battery module 10 through two circuits: a coolant circulation circuit and a refrigerant circulation circuit.

[0032] The battery module 10 is the object of the cooling system of this invention, and it integrates a battery cooling plate. The battery module 10 generates a large amount of heat during operation, which needs to be dissipated promptly by the cooling system. The battery cooling plate is typically integrated at the bottom of the battery module 10 and employs a dual-channel design. Coolant flows through the channels within the cooling plate, exchanging heat with the metal walls in contact with the battery, thus removing the heat generated by the battery. The dual-channel design ensures uniform distribution of coolant within the cooling plate, guaranteeing consistent cooling across all parts of the battery pack, with a temperature difference of less than 2°C. The battery cooling plate is made of a high thermal conductivity metal material, such as aluminum alloy or copper alloy, to ensure excellent thermal conductivity.

[0033] The chiller unit 4 is the core refrigeration unit of the cooling system of this invention, comprising a compressor 5, a condenser 6, an expansion valve 7, and an evaporator 8. A complete vapor compression refrigeration cycle is formed within the chiller unit 4, achieving heat transfer from the low-temperature end to the high-temperature end through the phase change process of the refrigerant. The chiller unit 4 adopts a modular installation design, with a compact overall structure, facilitating integrated deployment on the locomotive. The chiller unit 4 is bolted to the locomotive roof, and the mounting base is inlaid with rubber vibration damping blocks, effectively buffering vibration and impact during locomotive operation.

[0034] Compressor 5 is integrated inside chiller unit 4. Its function is to compress low-temperature, low-pressure refrigerant gas into high-temperature, high-pressure refrigerant gas. Compressor 5 is the power source of the refrigeration cycle, and its performance directly affects the cooling capacity and energy efficiency ratio of the chiller unit. In this embodiment of the invention, compressor 5 is a variable frequency compressor, which supports speed regulation and can dynamically adjust its operating power according to actual heat load requirements to achieve energy-saving operation.

[0035] The condenser 6 is integrated inside the chiller unit 4, and its function is to cool and condense the high-temperature, high-pressure refrigerant gas. In the condenser 6, the refrigerant gas exchanges heat with the ambient air, releasing heat and condensing into a medium-temperature, high-pressure liquid refrigerant. The condenser 6 uses forced air cooling, with forced ventilation provided by the cooling fan 12 to enhance air convection and improve condensation efficiency. The cooling fan 12 is also installed inside the chiller unit 4, and its speed can be adjusted by the thermal management controller 3.

[0036] Expansion valve 7 is integrated with the throttling device inside chiller unit 4. Its function is to throttle and reduce the pressure of the medium-temperature, high-pressure liquid refrigerant. After passing through expansion valve 7, the refrigerant's pressure and temperature are significantly reduced, becoming a low-temperature, low-pressure mist or gas-liquid mixture, preparing it for subsequent evaporation and heat absorption in evaporator 8. Expansion valve 7 is an electronic expansion valve, and its opening can be precisely adjusted by thermal management controller 3 to control the refrigerant flow rate into evaporator 8.

[0037] Evaporator 8 and plate heat exchanger 9 are integrated and installed inside chiller unit 4. Evaporator 8 is a key component for absorbing heat in the refrigeration cycle. The low-temperature, low-pressure refrigerant absorbs heat from the battery coolant circuit here, evaporating into a low-temperature, low-pressure gaseous refrigerant. Evaporator 8 and the coolant side of plate heat exchanger 9 form a heat exchange interface. The heated coolant from battery module 10 releases heat on the coolant side of plate heat exchanger 9, which is absorbed by the refrigerant, lowering its temperature. Plate heat exchanger 9 is a key heat exchange component connecting the coolant circuit and the refrigerant circuit. Its plate structure offers advantages such as high heat exchange efficiency, small footprint, and light weight. Integrating evaporator 8 and plate heat exchanger 9 reduces external piping connections, lowers heat loss, and improves system integration and reliability.

[0038] The coolant circuit connects the battery module 10 and the chiller unit 4, forming a closed-loop coolant circulation. The main components of the coolant circuit include the battery cooling plate, the coolant side of the plate heat exchanger 9, the circulation pump 11, and connecting pipes. The circulation pump 11 is integrated inside the chiller unit 4, providing power for the coolant circulation. The circulation pump 11 drives the coolant to flow in the coolant circuit, carrying the heat generated by the battery module 10 to the plate heat exchanger 9, and then pumping the cooled coolant back to the battery module 10. In this embodiment, the coolant is an ethylene glycol-water solution, which has advantages such as low freezing point, high boiling point, good thermal stability, and low corrosiveness, making it suitable for working environments with a wide temperature range. The circulation pump 11 also uses a variable frequency pump, supporting speed adjustment, allowing the coolant flow rate to be adjusted according to cooling requirements.

[0039] The thermal management controller 3 is integrated into the battery system and connected to the battery management module (BMS) 1. The thermal management controller 3 is the control core of the cooling system, responsible for receiving temperature monitoring signals from the battery management module 1 and issuing control commands according to a preset control strategy. The thermal management controller 3 employs a variable frequency control strategy based on battery heat load prediction, which can predict heat load demands based on the actual battery temperature and temperature change trends, and adjust the cooling power in advance to avoid excessive temperature fluctuations. The input terminal of the thermal management controller 3 is connected to a temperature sensor 2, which is integrated into the battery management module 1 and used to acquire battery temperature signals in real time.

[0040] The output of the thermal management controller 3 is connected to the compressor 5, circulating pump 11, condenser fan 12, and expansion valve 7, among other actuators. The thermal management controller 3 achieves precise operation of the cooling system through coordinated control of these actuators. The specific control logic is as follows: When the battery temperature exceeds a first preset threshold (e.g., 35°C), the thermal management controller 3 starts the circulating pump 11 and chiller unit 4, and the cooling system enters cooling mode; based on battery temperature feedback, the thermal management controller 3 adjusts the operating frequency of the compressor 5, the speed of the circulating pump 11, and the opening of the expansion valve 7 to match the cooling power with the battery heat load; as the battery temperature decreases, the thermal management controller 3 gradually reduces the operating frequency of the compressor 5 or puts it into intermittent operation mode to reduce cooling power; when the battery temperature drops to a second preset threshold (e.g., 30°C), the cooling system enters maintenance mode or standby state.

[0041] The cooling system of this embodiment is also equipped with a heater 13, which is connected to the mounting interface reserved in the battery module 10. The heater 13 is mainly used for battery preheating in low-temperature environments. When the ambient temperature is too low, the charging and discharging performance of the battery will be affected. At this time, the heater 13 can be used to preheat the battery so that it can reach the appropriate operating temperature as soon as possible. The heater 13 can be automatically controlled by the thermal management controller 3 according to the ambient temperature signal, or it can be manually started by the operator.

[0042] In this embodiment of the invention, the cooling system connects various components via accessories such as pipe supports 14, metal clamps 15, and connecting flanges 16. The pipe supports 14 are made of high-strength sheet metal and are used to support and fix the pipes, bearing the weight of the pipes and vibration loads. The metal clamps 15 are professional products selected from the rail transit industry and are used to tighten pipe connections, effectively preventing the impact of locomotive vibration on the stability of the pipe connections. The connecting flanges 16 use a flange installation method, facilitating the overall disassembly and maintenance of the pipes. The O-rings 17 are made of fluororubber, providing good sealing performance, resistance to coolant corrosion, and effectively preventing coolant leakage.

[0043] The working principle of the cooling system in this embodiment of the invention is as follows: System startup and thermal load assessment. The battery management module 1 monitors the temperature of the battery module 10 in real time via the temperature sensor 2. When the battery temperature exceeds a first preset threshold (35°C), the battery management module 1 sends a cooling command request to the thermal management controller 3. Upon receiving the request command, the thermal management controller 3 first determines whether the cooling system needs to be activated. If the battery temperature continues to rise and exceeds the threshold, it enters cooling mode.

[0044] Cooling cycle and active refrigeration start-up. The thermal management controller 3 sends a start command to the circulation pump 11, which starts operating and drives the coolant to circulate in the coolant circuit. At the same time, the thermal management controller 3 sends a start command to the chiller unit 4, which starts operating. The compressor 5 starts, compressing the low-temperature, low-pressure refrigerant gas into a high-temperature, high-pressure refrigerant gas. The high-pressure refrigerant gas is delivered to the condenser 6, where it exchanges heat with the ambient air forced in by the cooling fan 12, condensing into a medium-temperature, high-pressure liquid refrigerant. The medium-temperature, high-pressure liquid refrigerant flows to the expansion valve 7, where it is throttled and depressurized, becoming a low-temperature, low-pressure mist-like mixed refrigerant. The mist-like refrigerant enters the evaporator side of the plate heat exchanger 9, ready to absorb heat from the coolant circuit.

[0045] Battery heat exchange. The circulating pump 11 drives the cryogenic coolant to flow through the battery cooling plate below the battery module 10. The dual-channel design inside the battery cooling plate ensures uniform distribution of the coolant, allowing for full contact with the battery and absorption of the heat generated by the battery. The heated coolant returns to the coolant side of the plate heat exchanger 9, releasing heat to the refrigerant. In the plate heat exchanger 9, the heat from the coolant is absorbed by the low-temperature, low-pressure atomized refrigerant, which evaporates into a low-temperature, low-pressure gaseous state. The cooled coolant is then pumped back to the battery cooling plate of the battery module 10 by the circulating pump 11 to continue absorbing heat, and this cycle repeats. The evaporated low-temperature, low-pressure gaseous refrigerant returns to the compressor 5, is compressed, and enters the next refrigeration cycle.

[0046] Intelligent adjustment and precise temperature control. The thermal management controller 3 receives feedback signals from the temperature sensor 2 in real time to obtain the actual battery temperature and temperature change trend. Based on changes in battery heat load, the thermal management controller 3 dynamically adjusts the operating frequency of the compressor 5, the speed of the circulation pump 11, and the opening of the expansion valve 7. The specific adjustment strategy is as follows: when the battery temperature is higher than the upper limit of the target temperature, the operating frequency of the compressor 5 and the speed of the circulation pump 11 are increased to improve cooling power; when the battery temperature is close to the target temperature, the operating frequency of the compressor 5 is reduced to decrease cooling power; when the battery temperature is stable within the target temperature range, the current operating state is maintained; when the battery temperature is lower than the lower limit of the target temperature, the operating frequency of the compressor 5 is further reduced or it is put into intermittent operation mode. Through this dynamic adjustment, the battery temperature can be stably maintained within the optimal operating range (e.g., 25-30℃).

[0047] System adjustment or standby. When the battery temperature drops to the second preset threshold (30°C), the thermal management controller 3 controls the compressor 5 to operate at a reduced frequency or enter intermittent operation mode to reduce cooling power and energy consumption. At this time, the circulation pump 11 continues to run, maintaining a low-speed circulation of coolant to ensure the rapid response capability of the cooling system. If the battery temperature continues to drop below the safe range, the thermal management controller 3 can shut down the chiller unit 4, maintaining only low-speed circulation of coolant or putting the system into standby mode. When the battery temperature rises again above the threshold, the system can quickly switch from standby mode to cooling mode.

[0048] The cooling system in this embodiment of the invention adopts a variable frequency control strategy based on battery heat load prediction to achieve precise matching of cooling power and efficient energy-saving operation.

[0049] Variable frequency control is the core technology of the control strategy in this invention. Traditional fixed-speed compressor refrigeration systems can only adjust the cooling power through start-stop control, which easily leads to problems such as large temperature fluctuations, high energy consumption, and short compressor life. This invention uses a variable frequency compressor 5, whose operating frequency can be continuously adjusted within a certain range. When the battery heat load is high, the compressor 5 operates at a higher frequency, providing greater cooling power; when the battery heat load is low, the compressor 5 operates at a lower frequency, providing less cooling power. This continuous adjustment method allows for precise matching of cooling power with battery heat load, avoiding energy waste.

[0050] In addition to the variable frequency control of compressor 5, thermal management controller 3 also coordinates the control of circulating pump 11 and expansion valve 7. Adjusting the speed of circulating pump 11 changes the flow rate of coolant, thus affecting the heat exchange efficiency of the cooling plate. Adjusting the opening of expansion valve 7 controls the flow rate of refrigerant entering evaporator 8, affecting the evaporation temperature and the thermodynamic state of the refrigerant. Through coordinated control of these three actuators, thermal management controller 3 can achieve optimal control of the overall performance of the cooling system.

[0051] This invention also employs a feedforward control strategy based on battery thermal load prediction. The thermal management controller 3 not only performs feedback control based on the current battery temperature, but also predicts future thermal load trends based on parameters such as the battery's charging / discharging state and current magnitude, adjusting the cooling power in advance. For example, when it detects that the battery is about to enter a high-current charging state, the thermal management controller 3 can increase the cooling power in advance to prepare for the upcoming high thermal load. This feedforward-feedback combined control strategy can effectively reduce temperature overshoot and fluctuations, improving control quality.

[0052] The cooling system of this invention fully considers the special operating conditions of rail transit locomotives in its structural and installation design.

[0053] In terms of mechanical structure, the chiller unit 4 adopts a modular design, integrating all major components—compressor 5, condenser 6, expansion valve 7, evaporator 8, plate heat exchanger 9, circulating pump 11, and cooling fan 12—into a compact housing. This design reduces external piping connections, lowers the risk of leakage, and improves system reliability. Simultaneously, the modular design facilitates overall disassembly and maintenance, shortening maintenance time.

[0054] In terms of vibration resistance, the mounting base of chiller unit 4 is inlaid with rubber vibration damping blocks. During locomotive operation, severe vibrations occur. If these vibrations are directly transmitted to the internal components of the chiller unit, it can lead to problems such as loosening of components, connection failure, and increased noise. The rubber vibration damping blocks can effectively absorb and isolate vibration energy, protecting internal components from vibration damage. The coolant circuit piping connections are fixed using pipe supports 14 and metal clamps 15. The metal clamps 15 are selected from professional products used in the rail transit industry, possessing reliable fastening and vibration damping performance.

[0055] In terms of sealing performance, all connections in the coolant circuit are sealed with O-rings 17. The O-rings 17 are made of fluororubber, which has excellent oil resistance, coolant resistance, and high-temperature resistance, maintaining a good sealing effect over a wide temperature range. The connecting flange 16 uses a flange connection method, which, in conjunction with the O-rings, ensures a reliable sealing connection while facilitating disassembly and maintenance.

[0056] In terms of corrosion resistance, ethylene glycol-water solution is selected as the cooling medium. Ethylene glycol-water solution has low corrosiveness to metal materials, protecting metal components in the coolant circuit from corrosion. Furthermore, adding appropriate corrosion inhibitors to the coolant further enhances the system's corrosion resistance. The casing of chiller unit 4 is made of corrosion-resistant materials, allowing it to withstand various harsh operating environments.

[0057] The cooling system of this invention has excellent temperature control performance and can meet the stringent thermal management requirements of power batteries for new energy vehicles.

[0058] Regarding temperature control accuracy, this invention achieves precise battery temperature control through the adoption of frequency conversion control and intelligent adjustment strategies. The thermal management controller 3 continuously adjusts the operating parameters of the compressor 5, circulating pump 11, and expansion valve 7 based on real-time feedback from the temperature sensor 2, ensuring the battery temperature is stably maintained within the target temperature range. The target temperature can be set according to the battery's characteristics and operating requirements; for example, 25-30℃ is the optimal operating temperature range for lithium batteries. The temperature control accuracy of this invention can reach ±1℃, meeting the stringent requirements of battery thermal management.

[0059] Regarding temperature uniformity, the battery cooling plate employs a dual-channel design, allowing the coolant to flow evenly within the plate and ensuring consistent cooling across all parts of the battery pack. The cooling plate is in direct contact with the battery, with heat transferred to the coolant through the metal walls. The use of high thermal conductivity metal materials and optimized channel design minimizes temperature differences within the battery pack. The temperature difference within the battery pack of this invention can be controlled within 2°C, far superior to the 5-10°C temperature difference of traditional air-cooled systems.

[0060] Regarding high-temperature adaptability, this invention employs an active cooling method using a chiller unit, meaning its cooling capacity is independent of ambient temperature. In extreme high-temperature environments of 45°C, the cooling effect of traditional air-cooled systems decreases significantly, but this invention can still maintain the battery at an operating temperature below 35°C. This is because the chiller unit produces low-temperature coolant through refrigerant circulation, and its cooling capacity depends primarily on the performance of the refrigeration system, rather than the ambient temperature. Even in high-temperature environments, the chiller unit can still provide sufficient cooling capacity to remove the heat generated by the battery.

[0061] Regarding low-temperature adaptability, this invention extends its capabilities to adapt to low-temperature operating environments through the heat pump mode of heater 13 and chiller unit. When the ambient temperature is too low, heater 13 can be activated to preheat the battery, allowing it to reach a suitable operating temperature as quickly as possible. The chiller unit can also reverse its cycle to form a heat pump mode, utilizing the waste heat from the compressor to heat the battery. This design enables the invention to operate normally within a wide temperature range of -30℃ to +50℃, demonstrating excellent environmental adaptability.

[0062] The cooling system of this invention has good energy efficiency characteristics and meets the requirements of energy conservation and environmental protection.

[0063] The energy-saving effect brought about by variable frequency control is the key to the energy efficiency optimization of this invention. Compared with traditional fixed-speed compressor refrigeration systems, variable frequency compressors have a higher energy efficiency ratio, especially under partial load conditions. Traditional systems can only adjust under partial load by starting and stopping, resulting in frequent compressor starts and stops, low efficiency, high energy consumption, and short lifespan. The variable frequency control system of this invention allows the compressor to always operate near its optimal efficiency point, significantly reducing energy consumption. According to experimental data, the variable frequency control system of this invention can save more than 30% energy compared to traditional fixed-speed systems.

[0064] The intelligent adjustment strategy further optimizes energy efficiency. The thermal management controller 3 dynamically adjusts the cooling power according to the actual heat load demand of the battery, avoiding energy waste caused by over-cooling. When the battery heat load is low, the system automatically reduces the cooling power; when the battery heat load is high, the system outputs a larger cooling power. This on-demand cooling control strategy can minimize unnecessary energy consumption.

[0065] The high heat exchange performance of plate heat exchanger 9 also contributes to improving system energy efficiency. Plate heat exchangers employ a corrugated plate structure, with coolant and refrigerant flowing counter-currently on both sides of the plates, forming highly efficient convective heat exchange. Compared to traditional shell-and-tube heat exchangers, plate heat exchangers can improve heat exchange efficiency by 30%-50%, meaning that for the same cooling capacity, the system consumes less energy.

[0066] The integrated design of evaporator 8 and plate heat exchanger 9 reduces the length of external piping, lowers the temperature rise and heat loss of coolant in the piping, and further improves the overall energy efficiency of the system.

[0067] The cooling system of this invention is easy to maintain, reducing maintenance and operating costs.

[0068] Modular design is the foundation of this invention's ease of maintenance. The chiller unit 4, as a single module, can be hoisted and replaced as a whole, eliminating the need to disassemble internal components individually. When a chiller unit malfunctions, maintenance personnel can quickly remove the faulty unit, replace it with a spare, and then transport the faulty unit back to the repair station for inspection. This design significantly reduces maintenance time and improves locomotive availability.

[0069] Flange connections simplify pipeline maintenance. The coolant circuit uses connecting flange 16 to connect various components; flange connections facilitate easy disassembly and assembly, allowing for convenient pipeline inspection and replacement. O-rings 17 serve as standard seals, offering easy replacement and reliable sealing. Pipe supports 14 and metal clamps 15 are standard-specification products, readily available in the market, resulting in low replacement costs.

[0070] The cooling fan 12 is a standard-specification product and can be replaced individually without replacing the entire chiller unit. Components such as the temperature sensor 2 and heater 13 use plug-in connections for easy maintenance. The thermal management controller 3 has fault diagnosis and alarm functions, enabling quick location of faulty components and guiding maintenance personnel to perform targeted repairs.

[0071] The coolant circuit design prioritizes ease of evacuation and refilling. The system features an evacuation valve and a refill port, allowing for convenient drainage of old coolant and refilling with new coolant. The coolant used is a long-life ethylene glycol-water solution, resulting in extended replacement intervals and reduced maintenance frequency.

[0072] In addition to basic cooling functions, the cooling system of this invention also has a variety of extended functions, which improves the applicability and flexibility of the system.

[0073] The heating function is an important extended function of this invention. In low-temperature environments, the charging and discharging performance of the battery will decrease, and it may even fail to function properly. The chiller unit 4 of this invention can reverse the cycle to form a heat pump mode, extracting heat from the ambient air and transferring it to the battery to heat it. Alternatively, the battery can be preheated by the heater 13 integrated into the system. This bidirectional temperature regulation function allows the invention to operate normally in both cold and hot regions, expanding the applicability of the locomotive.

[0074] Remote monitoring is another extended function of this invention. The thermal management controller 3 can be networked with the locomotive's control system to upload the operating parameters of the cooling system (temperature, pressure, flow rate, power, etc.) to the monitoring center in real time. The monitoring center can remotely view the battery thermal management status of each locomotive, promptly detect abnormalities, and issue early warnings. This remote monitoring function helps to achieve preventative maintenance and improve the operational safety and reliability of the locomotive.

[0075] Energy recovery is an energy-saving extension of this invention. Locomotives generate a significant amount of heat during braking; recovering and utilizing this heat can improve the locomotive's energy efficiency. The cooling system of this invention can recover a portion of the heat generated during braking, using it to heat the carriages or preheat the batteries, reducing additional heating energy consumption. This energy recovery design aligns with the energy conservation and emission reduction development direction of the rail transit industry.

[0076] The multi-unit coordinated control function is applicable to locomotives with multiple battery packs. The thermal management controller 3 of this invention can simultaneously manage multiple chiller units 4, achieving coordinated operation among them. When the heat load of a certain battery pack is high, the cooling power of the corresponding chiller unit can be increased; when the heat load of a certain battery pack is low, the power of its chiller unit can be reduced or it can be put into standby mode. This multi-unit coordinated control can optimize overall energy efficiency and avoid resource waste.

[0077] In summary, this invention achieves efficient, precise, and reliable cooling of the power batteries in new energy locomotives by introducing an active refrigeration cycle based on a chiller unit, combined with frequency conversion control technology and intelligent temperature regulation strategies. The cooling system of this invention is particularly suitable for high-heat-generating conditions such as high-power fast charging and heavy-load hill climbing, maintaining good cooling performance even in extreme high-temperature environments. It also features low-temperature heating capabilities and a wide operating temperature range, exhibiting excellent environmental adaptability. Modular design and standardized interfaces facilitate system maintenance and reduce operating costs. This invention provides an effective technical solution for battery thermal management in new energy locomotives in the rail transit industry.

[0078] It should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Modifications or substitutions to the technical solutions described in the foregoing embodiments do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A cooling system for a power battery in a new energy locomotive, characterized in that, include: The battery module integrates a battery cooling plate and a coolant circuit; A circulation pump is provided in the coolant circuit to drive the coolant to circulate. A water chiller unit, comprising a compressor, a condenser, an expansion valve, and an evaporator; A plate heat exchanger is disposed between the cooling liquid circuit and the refrigerant circuit of the chiller unit; The battery management module includes a thermal management controller and a temperature sensor. The thermal management controller controls the operation of the chiller and the circulating pump based on the battery temperature signal from the temperature sensor. The evaporator and the plate heat exchanger are integrated.

2. The cooling system for the power battery of a new energy locomotive according to claim 1, characterized in that: The thermal management controller employs a variable frequency control strategy to adjust the operating frequency of the compressor according to the actual heat load of the battery.

3. The cooling system for the power battery of a new energy locomotive according to claim 1, characterized in that: The thermal management controller dynamically matches the actual thermal load of the battery by adjusting the rotational speed of the circulating pump and the opening of the expansion valve.

4. The cooling system for the power battery of a new energy locomotive according to claim 1, characterized in that: The chiller unit also includes a condenser fan, which is used to provide forced air cooling for the condenser.

5. The cooling system for the power battery of a new energy locomotive according to claim 1, characterized in that: The coolant used is an ethylene glycol-water solution.

6. The cooling system for the power battery of a new energy locomotive according to claim 1, characterized in that: The battery cooling plate is located at the bottom of the battery module and has a dual-channel design inside.

7. The cooling system for the power battery of a new energy locomotive according to claim 1, characterized in that: The cooling system also includes a heater connected to the battery module for preheating the battery in a low-temperature environment.

8. The cooling system for the power battery of a new energy locomotive according to claim 1, characterized in that: The chiller unit adopts a modular installation design, and the chiller unit mounting base is inlaid with rubber vibration damping blocks.

9. The cooling system for the power battery of a new energy locomotive according to claim 1, characterized in that: The coolant circuit also includes pipe supports, metal clamps, and connecting flanges. The pipe supports are made of high-strength sheet metal, the metal clamps are used to fix the pipes, and the connecting flanges are installed using a flange mounting method.

10. The cooling method for the cooling system of the power battery of a new energy locomotive according to claim 1, characterized in that, Includes the following steps: The battery management module monitors the battery temperature in real time. When the battery temperature exceeds the first preset threshold, it sends a cooling command request to the thermal management controller. After receiving a cooling command, the thermal management controller starts the circulation pump to drive the coolant to circulate in the coolant circuit, and at the same time starts the chiller unit to circulate the refrigerant in the refrigeration cycle circuit. The coolant flows through the battery cooling plate below the battery module, absorbing the heat generated by the battery. The heated coolant then enters the coolant side of the plate heat exchanger. In the plate heat exchanger, the heat of the coolant is absorbed by the low-temperature, low-pressure refrigerant. The cooled refrigerant is then evaporated into a low-temperature, low-pressure gaseous refrigerant and returned to the compressor. The thermal management controller receives real-time battery temperature feedback and adjusts the compressor's operating frequency and the circulation pump's speed according to the temperature deviation, so that the battery temperature is stably maintained within the target temperature range. When the battery temperature drops to the second preset threshold, the thermal management controller controls the compressor to operate at a reduced frequency or enter an intermittent operation mode.

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