A pressure regulating device based on a battery direct heating device

Abstract

This utility model discloses a pressure regulating device based on a battery direct heating system, used to solve the problems of flow distortion and system instability caused by refrigerant bubbles reaching their bubble point during low-temperature testing of new energy vehicle batteries. The device comprises a refrigeration cycle consisting of a compressor, oil separator, battery cold plate, evaporator, gas-liquid separator, and connecting pipelines. A direct-heating subcooled plate heat exchanger and a liquid receiver are connected in series at the battery cold plate outlet. High-temperature, high-pressure liquid refrigerant enters the direct-heating subcooled plate heat exchanger from the battery cold plate via an outlet ball valve. Forced cooling by an independent cold source raises the subcooling degree to above 5°C, completely eliminating bubbles. The subcooled refrigerant then enters the liquid receiver for pressure stabilization and buffering via a one-way valve, and finally flows to the evaporation side via a dryer filter and flow meter. This significantly improves the refrigerant subcooling degree, eliminates bubble interference with the flow meter, enhances system pressure stability, and ensures the accuracy of low-temperature battery test data.

Description

Technical Field

[0001] This utility model relates to the field of new energy vehicle battery technology, specifically to a pressure regulating device based on a battery direct heating device. Background Technology

[0002] In recent years, the new energy vehicle industry has developed rapidly, and the testing and verification of the performance, safety, and lifespan of power batteries, as their core components, has become crucial. In low-temperature environment testing of battery modules, conventional direct-heating battery testing equipment (usually employing heat pumps or refrigerant direct cooling / heating technology) is widely used to simulate the heating requirements of batteries under low-temperature conditions. However, such equipment suffers from a significant technical bottleneck at the end of the low-temperature heating process:

[0003] After the refrigerant has heated the battery within the battery cold plate, the temperature of the flowing liquid refrigerant approaches its saturation temperature at its current pressure. At this point, if the system pressure fluctuates slightly, or if the liquid refrigerant experiences a small pressure drop or temperature rise in subsequent pipelines, it is very easy for it to reach or exceed its bubble point, causing some of the liquid refrigerant to flash into gas and form bubbles.

[0004] The generation of these bubbles can lead to a series of problems: 1) Flow measurement distortion: The presence of bubbles will cause the fluid flowing through the flow meter to become a gas-liquid two-phase flow, resulting in the flow meter reading deviating significantly from the actual liquid refrigerant flow rate, affecting the system control accuracy and the reliability of test data. 2) Decreased system stability: The increased compressibility of the two-phase fluid leads to aggravated system pressure fluctuations, which may cause oscillations in control components such as expansion valves, disrupting the stability of the thermodynamic cycle.

[0005] Therefore, there is an urgent need for a technical solution that can effectively eliminate refrigerant bubbles, ensure stable delivery of liquid refrigerant, and improve the overall stability and testing accuracy of the system, especially in the final stage of low-temperature heating in battery direct heating testing equipment. Utility Model Content

[0006] The purpose of this invention is to provide a pressure regulating device based on a battery direct heating device, which aims to overcome the defects of the prior art and solve the problems of flow distortion and system instability caused by the refrigerant reaching its bubble point and generating bubbles during low-temperature testing of new energy vehicle batteries.

[0007] To address this, this invention proposes a pressure regulating device based on a battery direct heating system, comprising a compressor, an oil separator, a battery cold plate, an evaporator, a gas-liquid separator, a liquid receiver, and a refrigeration cycle loop consisting of connecting pipes; wherein, the inlet of the oil separator is connected to the compressor exhaust port; the inlet of the gas-liquid separator is connected to the evaporator outlet, and the outlet is connected to the compressor suction port; the outlet end of the battery cold plate is sequentially connected in series to a direct heating subcooled plate heat exchanger and a liquid receiver; the direct heating subcooled plate heat exchanger is externally connected to an independent cold source circulation loop to forcibly cool the high-temperature, high-pressure liquid refrigerant flowing out of the battery cold plate, significantly increasing its subcooling degree.

[0008] As a preferred technical solution of this application, the inlet end of the direct-heating subcooled plate heat exchanger is connected to the battery cold plate outlet through a direct-heating outlet ball valve, and the outlet end is connected to the liquid reservoir inlet through a one-way valve.

[0009] As a preferred technical solution of this application, it further includes: a condensing pressure regulating valve and an expansion valve, wherein the condensing pressure regulating valve is connected in series in the pipeline between the oil separator outlet and the battery cold plate inlet; and the expansion valve outlet is connected to the evaporator inlet.

[0010] As a preferred technical solution of this application, the outlet of the liquid reservoir is connected in series with a dryer filter, a sight glass, a flow meter, a solenoid valve and an expansion valve.

[0011] As a preferred technical solution of this application, the flow meter is a Coriolis mass flow meter, located downstream of the dryer filter and in the single-phase liquid refrigerant flow path.

[0012] As a preferred technical solution of this application, the condensing pressure regulating valve is a mechanical or electronic pressure regulating valve, used to maintain the refrigerant condensing pressure in the battery cold plate above a set threshold.

[0013] As a preferred technical solution of this application, the direct-heating subcooled plate heat exchanger is a plate heat exchanger, whose main channel is connected in series between the battery cold plate and the liquid storage tank, and the secondary channel is connected to an independent cold source circulation loop.

[0014] As a preferred technical solution of this application, the independent cold source is externally supplied cooling water or ethylene glycol solution.

[0015] As a preferred technical solution of this application, the one-way valve is disposed between the outlet of the direct-heating subcooled plate heat exchanger and the inlet of the liquid receiver to prevent refrigerant backflow.

[0016] The pressure regulating device based on battery direct heating equipment provided by this utility model innovatively integrates a direct heating subcooled plate heat exchanger into the conventional battery direct heating test circuit, bringing the following significant benefits:

[0017] 1) Significantly eliminates bubbles and improves system stability: The core advantage of this device lies in its ability to significantly increase the subcooling of the high-temperature, high-pressure liquid refrigerant flowing from the battery cold plate outlet. By forcibly cooling this portion of liquid refrigerant, its temperature is made far below the saturation temperature at the current pressure. Even if there are slight pressure drops or temperature rises in subsequent pipelines, the refrigerant state can safely stay away from the bubble point region, fundamentally eliminating the conditions for bubble formation.

[0018] 2) Ensuring flow measurement accuracy: The refrigerant entering the flow meter is kept in a pure, supercooled single-phase liquid state, ensuring high accuracy and reliability of flow measurement, and providing a solid foundation for precise control of the battery heating process.

[0019] 3) Optimize the evaporation process: Liquid refrigerant with high subcooling has greater sensible heat absorption potential before entering the evaporator, which helps the refrigerant in the evaporator to evaporate more completely and stably, improves evaporation efficiency, and helps maintain a stable superheat of compressor return gas.

[0020] 4) Enhanced system stability: Improved resistance of the entire thermodynamic cycle system to external disturbances (such as pressure fluctuations and changes in ambient temperature), resulting in more stable and reliable operation.

[0021] 5) Improved test accuracy: Improved system stability and flow accuracy directly ensure the accuracy and repeatability of battery module heating test data in low-temperature environments.

[0022] 6) Extend equipment life: Reduces the risk of two-phase flow and cavitation, helps protect precision components such as flow meters and expansion valves, and extends the overall service life of the equipment.

[0023] In addition to the purposes, features, and advantages described above, this application has other purposes, features, and advantages. A further detailed description of this application will be provided below with reference to the figures. Attached Figure Description

[0024] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0025] Figure 1 This is a schematic diagram of the pressure regulating device based on a battery direct heating device according to the present invention.

[0026] Explanation of reference numerals in the attached diagram: 1. Compressor; 2. Oil separator; 3. Solenoid valve; 4. Condensing pressure regulating valve; 5. Inlet ball valve; 6. Battery cold plate; 7. Outlet ball valve; 8. Direct-heating subcooled plate heat exchanger; 9. Check valve; 10. Liquid receiver; 11. Dryer filter; 12. Sight glass; 13. Flow meter; 14. Solenoid valve; 15. Expansion valve; 16. Evaporator; 17. Gas-liquid separator. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] like Figure 1 As shown, the pressure regulating device based on battery direct heating equipment of this utility model mainly includes a compressor 1, an oil separator 2, a solenoid valve 3, a condensing pressure regulating valve 4, a direct heating inlet ball valve 5, a battery cold plate 6, a direct heating outlet ball valve 7, a direct heating subcooled plate heat exchanger 8, a one-way valve 9, a liquid receiver 10, a dryer filter 11, a sight glass 12, a flow meter 13, a solenoid valve 14, an expansion valve 15, an evaporator 16, and a gas-liquid separator 17, etc., which are connected by pipelines to form a complete refrigerant circulation loop. Specifically, the refrigerant circulation loop includes the following steps:

[0029] Compression and oil-gas separation: Compressor 1 starts, drawing in low-temperature, low-pressure gaseous refrigerant from gas-liquid separator 17, compressing it into high-temperature, high-pressure gas, and discharging it. This high-temperature, high-pressure gas first enters oil separator 2, where entrained refrigeration lubricating oil is separated. The clean, high-pressure gas after separation flows out from the top outlet of oil separator 2.

[0030] Direct heating circuit injection: High-pressure gas flows through solenoid valve 3, and then the opening is adjusted by condensing pressure regulating valve 4 to maintain the system condensing pressure within the set range. The adjusted high-pressure gas then enters the battery cold plate 6 through direct heating inlet ball valve 5. Solenoid valve 3 controls the on / off state of the direct heating circuit; condensing pressure regulating valve 4 is a mechanical or electronic pressure regulating valve that can automatically adjust its opening according to the high-pressure side pressure of the system to maintain the system condensing pressure within the set range, ensuring the effective condensation process within the battery cold plate; and direct heating inlet ball valve 5 is used for maintenance isolation.

[0031] Battery heating and condensation: Inside the battery cold plate 6, the high-temperature and high-pressure refrigerant gas releases heat to the low-temperature battery module and condenses itself into a high-temperature and high-pressure liquid refrigerant (the temperature is close to the saturation temperature under its condensation pressure), thereby heating the battery.

[0032] Key subcooling process: The high-temperature, high-pressure liquid refrigerant flowing from the outlet of the battery cold plate 6 immediately enters the core component—the direct-heated subcooled plate heat exchanger 8—after passing through the direct-heated outlet ball valve 7 (for maintenance isolation). In this plate heat exchanger, this portion of the liquid refrigerant is forcibly cooled using an independent low-temperature cold source (low-temperature refrigerant from the evaporator 16 loop; or external cooling water / ethylene glycol solution). By precisely controlling the cooling intensity, its outlet temperature is significantly reduced, achieving a sufficiently large subcooling (e.g., subcooling >5°C or even higher, determined based on system design and environmental requirements).

[0033] Storage and purification: After deep subcooling, the high-pressure liquid refrigerant leaves the direct-heated subcooled plate heat exchanger 8 and enters the liquid receiver 10 through the one-way valve 9. The one-way valve 9 prevents refrigerant backflow, and the liquid receiver 10 stores the subcooled liquid refrigerant; further separates any remaining trace bubbles through gravity settling; and provides a stable supply of liquid refrigerant to the downstream expansion valve 16.

[0034] Drying, filtration and monitoring: Liquid refrigerant flows out from the bottom of the liquid receiver 10 and passes in sequence through the dryer filter 11 (to adsorb moisture and impurities), the sight glass 12 (to observe the refrigerant flow status and desiccant humidity indication), and the flow meter 13 (to accurately measure the flow rate of single-phase liquid refrigerant).

[0035] Throttling and Evaporation: Liquid refrigerant flows through solenoid valve 14 to control the on / off state of the evaporation circuit, and then enters expansion valve 15. Expansion valve 15 throttles and reduces pressure according to the superheat at the evaporator outlet or system requirements, turning the high-pressure liquid refrigerant into a low-temperature, low-pressure gas-liquid two-phase mixture, which then enters evaporator 16.

[0036] Heat absorption evaporation and gas-liquid separation: In evaporator 16, the low-temperature, low-pressure refrigerant absorbs heat from the environment and completely evaporates into a low-temperature, low-pressure gaseous refrigerant. The evaporated gas enters gas-liquid separator 17, which separates any entrained liquid droplets, ensuring that only dry, saturated, or superheated gas is drawn into compressor 1 to complete the entire cycle.

[0037] In this case, the direct-heating subcooled plate heat exchanger 8 is typically designed as a highly efficient and compact plate heat exchanger. Its main channel is connected in series on the main pipeline between the outlet of the battery cold plate 6 and the inlet of the liquid receiver 10, used to cool the high-temperature liquid refrigerant exiting from the battery cold plate. The secondary channel is connected to a low-temperature cold source circulation loop. By adjusting the flow rate or temperature of the cold source in the secondary channel, the subcooling of the refrigerant at the outlet of the main channel can be precisely controlled, ensuring that it remains liquid in subsequent processes.

[0038] In addition, the condensing pressure regulating valve 4 ensures that the high-pressure side of the system maintains a sufficiently high pressure in low-temperature environments or under low loads, keeping the refrigerant condensing pressure in the battery cold plate 6 above the set threshold, so that the refrigerant can condense and release heat at a higher temperature to meet the battery heating requirements, while preventing instability caused by excessively low pressure.

[0039] Since the inlet refrigerant is fully subcooled by the direct-heating subcooled plate heat exchanger 8, ensuring single-phase liquid flow, a high-precision single-phase liquid flow meter 13 (such as a Coriolis mass flow meter) can be selected to provide an accurate refrigerant circulation signal for system control.

[0040] The liquid receiver 10, installed after the subcooling process, provides additional buffer volume and can further settle the few bubbles that may be generated by temperature rise or minor disturbances, providing a more stable supply of liquid refrigerant downstream.

[0041] This invention addresses the critical issue of refrigerant bubble formation at the end of low-temperature heating in conventional equipment by installing a dedicated direct-heating subcooled plate heat exchanger 8 downstream of the battery cold plate outlet. This active subcooling of the high-temperature, high-pressure liquid refrigerant after heating / condensation effectively solves the problem of refrigerant nearing its bubble point generating bubbles at the end of low-temperature heating. This solution significantly improves the accuracy of system flow measurement, operational stability, heat exchange efficiency, and the reliability of battery test data, demonstrating outstanding practical value.

[0042] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A pressure regulating device based on a battery direct heating apparatus, characterized by, It includes a refrigeration cycle circuit consisting of a compressor (1), an oil separator (2), a battery cold plate (6), an evaporator (16), a gas-liquid separator (17), a liquid receiver (10), and connecting pipes. The oil separator (2) is connected to the exhaust port of the compressor (1) at its inlet; the gas-liquid separator (17) is connected to the outlet of the evaporator (16) at its inlet and to the suction port of the compressor (1) at its outlet; the battery cold plate (6) is connected in series with a direct-heating subcooled plate heat exchanger (8) and a liquid receiver (10); the direct-heating subcooled plate heat exchanger (8) is connected to an independent cold source circulation loop to force-cool the high-temperature and high-pressure liquid refrigerant flowing out of the battery cold plate (6), thereby significantly increasing its subcooling degree.

2. The battery-based direct heating appliance pressure regulating device of claim 1, wherein, The inlet end of the direct-heating subcooled plate heat exchanger (8) is connected to the outlet of the battery cold plate (6) through the direct-heating outlet ball valve (7), and the outlet end is connected to the inlet of the liquid reservoir (10) through the one-way valve (9).

3. The pressure regulating device based on a battery direct heating device according to claim 2, characterized in that, Also includes: The condensing pressure regulating valve (4) and the expansion valve (15) are connected in series on the pipeline between the outlet of the oil separator (2) and the inlet of the battery cold plate (6); the outlet of the expansion valve (15) is connected to the inlet of the evaporator (16).

4. The pressure regulating device based on a battery direct heating device according to claim 3, characterized in that, The outlet of the liquid reservoir (10) is connected in series with a dryer filter (11), a sight glass (12), a flow meter (13), a solenoid valve (14), and an expansion valve (15).

5. The pressure regulating device based on a battery direct heating device according to claim 4, characterized in that, The flow meter (13) is a Coriolis mass flow meter, located downstream of the dryer filter (11) and in the single-phase liquid refrigerant flow path.

6. The pressure regulating device based on a battery direct heating device according to claim 3, characterized in that, The condensing pressure regulating valve (4) is a mechanical or electronic pressure regulating valve used to maintain the refrigerant condensing pressure in the battery cold plate (6) above a set threshold.

7. The pressure regulating device based on a battery direct heating device according to claim 1, characterized in that, The direct-heating subcooled plate heat exchanger (8) is a plate heat exchanger, whose main channel is connected in series between the battery cold plate (6) and the liquid storage tank (10), and the secondary channel is connected to an independent cold source circulation loop.

8. The pressure regulating device based on a battery direct heating device according to claim 7, characterized in that, The independent cold source is externally supplied cooling water or ethylene glycol solution.

9. The pressure regulating device based on a battery direct heating device according to claim 2, characterized in that, The one-way valve (9) is located between the outlet of the direct-heating subcooled plate heat exchanger (8) and the inlet of the liquid receiver (10) to prevent refrigerant backflow.

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