Leakage detection method for liquid cooling pipeline, liquid cooling system, and charging pile

Abstract

A leakage detection method for a liquid cooling pipeline, comprising the following steps: pretreating a circulation pipeline (2) to remove air in the circulation pipeline (2); regulating the internal pressure of the circulation pipeline (2) to P and then locking the circulation pipeline (2); and after the locked state of the circulation pipeline (2) is kept for a first preset duration S, detecting whether the pressure drop ∆P in the circulation pipeline (2) exceeds a preset threshold, and determining a leakage situation on the basis of the result. The leakage detection method can achieve leakage detection of the whole circulation pipeline (2), has high reliability and low cost, and can reduce the occupied volume of a liquid cooling system. Also provided are a liquid cooling system and a charging pile.

Description

Liquid cooling pipeline leakage detection method, liquid cooling system and charging pile Technical Field

[0001] The present application belongs to the technical field of charging piles, and in particular relates to a liquid cooling pipeline leakage detection method, a liquid cooling system and a charging pile. Background Art

[0002] In the draft for comment on GB / T20234-4, "Connection Devices for Conductive Charging of Electric Vehicles Part 4: High-Power DC Charging Interface," major automakers and charging station manufacturers reached a consensus on leak detection for coolant in liquid-cooled charging guns, but there was no consensus on how to detect leaks. During use, charging guns and connecting cables are subject to various complex scenarios, including dragging, dropping, bending, ground friction, and vehicle overrun. The cooling lines within these components are more fragile than other components, and there is a risk of leakage if the cooling lines are damaged. If the coolant is conductive, such as an ethylene glycol solution, leaks could cause electric shock to users plugging and unplugging the charging gun. The traditional approach is to add leak detection sensors. However, leaks can occur in the entire circulation line from the charging gun to the heat dissipation unit, making it difficult for leak sensors to detect all possible leak locations. Technical issues

[0003] The technical purpose of this application is to provide a liquid cooling pipeline leakage detection method, a liquid cooling system and a charging pile, which can simultaneously realize leakage detection of the entire circulation pipeline from the heat dissipation unit to the charging gun. Technical Solutions

[0004] To solve the above technical problems, the present application is implemented as follows: a liquid cooling pipeline leakage detection method is provided, which is used to detect leakage in the liquid cooling pipeline. The liquid cooling pipeline includes a heat dissipation unit and a circulation pipeline connected to the heat dissipation unit at both ends to form a circulation loop. A pressure sensor is provided in the circulation pipeline. The leakage detection method includes the following steps:

[0005] Pre-treat the circulation pipeline to remove the air in the circulation pipeline;

[0006] Regulating the internal pressure of the circulation pipeline to P and then locking it;

[0007] After the locked state of the circulation pipeline is maintained for a first preset time length S, the pressure drop ΔP in the circulation pipeline is detected to see whether it exceeds a preset threshold value. If ΔP is less than or equal to the preset threshold value, it is determined that there is no leakage; if ΔP is greater than the preset threshold value, it is determined that there is a leakage; wherein, the first preset time length S is the length of the shortest detection cycle of the leakage detection, and the pressure drop ΔP is the difference between P and the pressure of the circulation pipeline after maintaining the first preset time length S.

[0008] Furthermore, the heat dissipation unit includes a pump; and the pre-processing of the circulation pipeline includes:

[0009] The pump runs at the maximum speed for a first running time, wherein the first running time is 20-50 seconds;

[0010] The pump runs for a second operating time after reducing the speed to the minimum, and the second operating time is 5-15 seconds.

[0011] Furthermore, the heat dissipation unit includes a first electric valve located at the water outlet and a second electric valve located at the water return port, and a pressure sensor is provided in the circulation pipeline; the internal pressure of the circulation pipeline is adjusted to P and then locked, including:

[0012] After the pump is reduced to a minimum speed and runs for a second operating time, slowly closing the second electric valve;

[0013] Detect the internal pressure of the circulation pipeline and compare the internal pressure of the circulation pipeline with P; if it is less than P, gradually increase the speed of the pump until the internal pressure of the circulation pipeline is equal to P; if it is equal to P, maintain the current speed of the pump; if it is greater than P, gradually reduce the speed of the pump until the internal pressure of the circulation pipeline is equal to P; when the maximum head of the pump is greater than Pm, Pm≤P≤Pn; when the maximum head of the pump is less than Pm, P<Pm<Pn; where Pn is the maximum pressure that the cooling pipe in the circulation pipeline can withstand before leaving the factory, and Pm is the maximum long-term allowable working pressure of the circulation pipeline;

[0014] After maintaining the current speed of the pump for a first maintaining time, the first electric valve is closed; the first maintaining time is 10-20s.

[0015] Furthermore, the preset threshold is a standard threshold K, which is a critical value at which there is no coolant leakage after the pressure drops by K within the rated pressure holding time S in a standard circulating pipeline locked state.

[0016] Furthermore, the circulation pipeline includes a water outlet manifold, a charging gun, and a water return manifold, which are sequentially connected between the water outlet and the water inlet of the heat dissipation unit. The water outlet manifold, the gun head of the charging gun, the gun tail of the charging gun, and the water outlet manifold are all provided with temperature sensors;

[0017] Before detecting whether the pressure drop ΔP in the circulation pipeline exceeds a preset threshold, the method includes:

[0018] Before the locked state of the circulation pipeline is maintained for a first preset time period S, detecting the temperatures of the water outlet manifold, the tip of the charging gun, the tail of the charging gun, and the water outlet manifold;

[0019] After the locked state of the circulation pipeline is maintained for a first preset time period S, detecting the temperatures of the water outlet manifold, the tip of the charging gun, the tail of the charging gun, and the water outlet manifold;

[0020] The difference Δt between the average temperatures of the water outlet manifold, the tip of the charging gun, the tail of the charging gun, and the water outlet manifold before and after maintaining the first preset time S is calculated, and the preset threshold is replaced by K+αΔtP, where α is the expansion coefficient of the coolant.

[0021] Furthermore, the locked state of the circulation pipeline is maintained for a first preset time period S, including:

[0022] The locked state of the circulation pipeline is maintained for a second preset time period D, D≥S, and the preset threshold is replaced by (D / S)·K+α△tP.

[0023] Furthermore, the locked state of the circulation pipeline is maintained for a first preset time period S, and detecting whether the pressure drop ΔP in the circulation pipeline exceeds a preset threshold value includes:

[0024] When D / S≥n, the second preset duration is divided into n average holding duration segments, where n is a positive integer;

[0025] Δt and ΔP of each average pressure holding time segment are calculated respectively, and whether the circulation pipeline is leaking in each average pressure holding time segment is determined respectively.

[0026] Furthermore, a liquid cooling system is provided, comprising a heat dissipation unit and a circulation pipeline connected to the heat dissipation unit at both ends to form a circulation loop; the heat dissipation unit comprises a first electric valve located at the water outlet, a second electric valve located at the return water outlet, and a pump, an expansion water tank, an expansion hose and a radiator connected to the loop between the first electric valve and the second electric valve; the circulation loop comprises a water outlet manifold, a charging gun and a return water manifold connected in sequence between the water outlet and the water inlet of the heat dissipation unit, and a pressure sensor is provided on the circulation loop side of the water outlet manifold or the return water manifold.

[0027] Furthermore, the water outlet manifold, the gun head of the charging gun, the gun tail of the charging gun and the water outlet manifold are all provided with temperature sensors.

[0028] Furthermore, a charging pile is provided, comprising a pile body and the liquid cooling system as described above, wherein the heat dissipation unit is installed inside the pile body, the charging gun and the pile body are detachably assembled, and the pile body is provided with a self-locking device for locking the charging gun;

[0029] The liquid cooling system is detected using the leakage detection method as described in any one of the above items. When the leakage detection method is performed and after a leak is detected, the self-locking device locks the charging gun to prohibit charging. Beneficial effects

[0030] Compared with the prior art, the liquid cooling pipe leakage detection method, liquid cooling system and charging pile in this application have the following beneficial effects:

[0031] In this solution, the air in the circulation pipeline is first discharged to prevent the coolant and air from mixing, thereby ensuring the reliability of leak detection. After that, the internal pressure of the circulation pipeline is adjusted to P and the circulation pipeline is locked and maintained for a first preset time length S. Then, the pressure drop △P in the circulation pipeline is detected to see if it exceeds the preset threshold. If △P is less than or equal to the preset threshold, it is determined that there is no leak. If △P is greater than the preset threshold, it is determined to be a leak, and the leakage state in the circulation pipeline can be detected. The leakage detection method of this solution does not require the installation of leak detection sensors at all locations in the circulation pipeline of the liquid cooling system. It can simultaneously realize leak detection of the entire circulation pipeline from the heat dissipation unit to the charging gun. The leak detection location is more comprehensive, the detection reliability is high, and the use of leak detection sensors can be reduced, which can save the cost of the liquid cooling system and reduce the volume it occupies. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a schematic structural diagram of a charging pile in an embodiment of the present application;

[0033] FIG2 is a schematic diagram of the structure of a liquid cooling system in an embodiment of the present application;

[0034] FIG3 is a flow chart of a method for detecting leakage of a liquid cooling pipeline in an embodiment of the present application.

[0035] In the accompanying drawings, the various reference numerals represent: 10, pile body; 1, heat dissipation unit; 2, circulation pipeline; 11, radiator; 12, expansion water tank; 13, pump; 14, expansion hose; 15, first electric valve; 16, second electric valve; 21, water outlet manifold; 22, charging gun; 23, return water manifold. Modes for Carrying Out the Invention

[0036] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be understood as limiting the present application. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application without making any creative efforts shall fall within the scope of protection of the present application.

[0037] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "circumferential", "radial", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply 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 this application.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0039] Charging guns are subject to various complex usage scenarios and conditions during use, such as being dropped, dragged, and bent. When abandoned by users near parking spaces, they can even be run over by vehicles. Traditional dry-cooled guns lack internal cooling tubes, and there's no effective way to cope with such harsh operating environments. Liquid-cooled guns, on the other hand, place even higher demands on the cooling tubes, the most prominent of which is safety. During charging, the cooling tubes inside liquid-cooled charging guns must maintain a certain pressure to ensure adequate heat dissipation for the gun and its cable. However, the operation process is subject to harsh operating conditions such as dropping, dragging, bending, and running over, which can easily lead to cooling tube leaks, bursts, and other failures. Coolant leaks not only affect the heat dissipation of the charging gun and cable, but can also cause internal short circuits in the gun and cable, resulting in electric shock accidents for operators.

[0040] In related technologies, common solutions and their advantages and disadvantages are as follows:

[0041] Improving the cooling pipe's resistance to falling, dragging, bending, and crushing can certainly reduce the risk of coolant leakage, but it cannot completely prevent coolant leakage. Therefore, it is necessary to constantly monitor the coolant for leaks.

[0042] Leak detection devices on the market install a leak detection sensor inside the charging gun head. When coolant leaks, it will drip onto the sensor, triggering an alarm. However, this method has a significant drawback. Because the charging gun is randomly placed, for example, when the charging gun is plugged into a charging station or a car, or when the charging gun is lying flat on the ground, the positional relationship between the leakage sensor and the cooling tube connection terminal may change from a top-to-bottom relationship to a left-to-right relationship. When a leak occurs, the coolant will flow down the cooling tube or may drip directly downward. The flow direction of the leaked coolant is completely random. If the leaked coolant does not drip onto the leak sensor, the leak detection will be completely ineffective.

[0043] Not only that, the leakage sensor is installed inside the charging gun and can only detect whether there is a leak in the cooling pipe inside the charging gun, but it cannot detect whether there is a leak in the cooling pipe inside the cable, the heat dissipation unit, or the connection between the cooling pipe and the heat dissipation unit. It cannot prevent leakage and electric shock accidents caused by coolant leakage.

[0044] Liquid level sensors or switches are a common leak detection method in the market. Specifically, they are installed inside the water tank and trigger an alarm when the liquid level falls below the minimum allowable level. However, this method has several drawbacks. It is only effective for rapid leaks in pipes. Liquid level sensors or switches are ineffective in the following scenarios:

[0045] A. When the leakage is very slow and the coolant level is always above the allowable level, the leakage of the entire circulation system cannot be detected and the alarm cannot be sounded;

[0046] B. When the coolant temperature is too high or too low, the coolant will expand and contract due to heat, causing the water level in the tank to fluctuate. It is then impossible to determine whether the level fluctuation is caused by leakage or by temperature.

[0047] C. After the charging gun and its accompanying liquid cooling unit have been used for a period of time, the coolant will slowly evaporate and lose. It is then difficult to determine whether this is normal evaporation or leakage. For example, the vent valve at the top of the water tank can be open to the atmosphere, while the liquid filling port at the top of the water tank can also be completely sealed from the atmosphere. These two methods are common in cooling units, but the coolant loss rates of the two different water tanks vary greatly.

[0048] In view of the above situations, it is impossible to determine whether there is a leak in the liquid cooling circulation system by using a liquid level sensor or liquid level switch detection method.

[0049] In conjunction with Figures 1-3, to address at least one of the drawbacks of the commonly used solutions in the related art, in this embodiment, a charging pile is provided, comprising a pile body 10 and a liquid cooling system. The liquid cooling system includes a heat dissipation unit 1 and a circulation pipeline 2 connected to the heat dissipation unit 1 at both ends to form a circulation loop. The heat dissipation unit 1 includes a first electric valve 15 at the water outlet, a second electric valve 16 at the water return outlet, and a pump 13, an expansion tank 12, an expansion hose 14, and a radiator 11 connected to the circuit between the first and second electric valves 15 and 16. The circulation pipeline 2 includes a water outlet manifold 21, a charging gun 22, and a water return manifold 23, which are sequentially connected between the water outlet and water inlet of the heat dissipation unit 1. A pressure sensor is provided on the circulation loop side of the water outlet manifold 21 or the water return manifold 23. The heat dissipation unit 1 is mounted inside the pile body 10. The charging gun 22 is detachably assembled with the pile body 10, and the pile body 10 is provided with a self-locking device for locking the charging gun 22.

[0050] This application uses an air heat exchanger as the radiator 11. Of course, other secondary heat exchange heat exchangers such as water cooling and direct cooling can also be used as the radiator 11. All such simple replacements are within the scope of protection of this application.

[0051] This embodiment also provides a liquid cooling pipeline leakage detection method, comprising the following steps:

[0052] S100, pre-treating the circulation pipeline 2 to remove the air in the circulation pipeline 2;

[0053] S200, regulating the internal pressure of circulation pipeline 2 to P and then locking;

[0054] S300, after the locked state of the circulation pipeline 2 is maintained for the first preset time length S, the pressure drop △P in the circulation pipeline 2 is detected to see whether it exceeds the preset threshold value. If △P is less than or equal to the preset threshold value, it is determined that there is no leakage; if △P is greater than the preset threshold value, it is determined that there is a leakage; wherein, the first preset time length S is the length of the shortest detection cycle of the leakage detection, and the pressure drop △P is the difference between P and the pressure of the circulation pipeline 2 after maintaining the first preset time length S.

[0055] In the charging pile of this embodiment, when the leakage detection method is being performed or after a leak is detected, the self-locking device locks the charging gun 22 to prohibit charging.

[0056] In this solution, the air in the circulation line 2 is first exhausted to prevent the coolant and air from mixing, thereby ensuring the reliability of leak detection. The internal pressure of the circulation line 2 is then adjusted to P, the circulation line 2 is locked, and maintained for a first preset time period S. The pressure drop ΔP in the circulation line is then detected to see if it exceeds a preset threshold. If ΔP is less than or equal to the preset threshold, it is determined to be non-leaking. If ΔP is greater than the preset threshold, it is determined to be leaking, thereby detecting the leakage state in the circulation line 2. The leak detection method of this solution eliminates the need to install leak detection sensors at various locations in the circulation line 2 of the liquid cooling system. Leak detection can be simultaneously performed on the entire circulation line 2 from the heat dissipation unit 1 to the charging gun 22. This provides a more comprehensive coverage of leak detection locations, improves detection reliability, and reduces the use of leak detection sensors, saving the cost of the liquid cooling system and reducing its occupied volume.

[0057] Specifically, the water outlet manifold 21, the charging gun 22 and the return water manifold 23 in the circulation pipeline 2 are connected by a cooling pipe, wherein the cooling pipe is buried inside the cable, thereby connecting the charging gun 22 and the heat dissipation unit 1 in the pile body 10. This application does not require additional sensors and does not occupy valuable space inside the cable and the charging gun 22. It can simultaneously perform leakage and pressure resistance tests on the cooling pipes, adapters and other liquid connectors inside the charging gun 22 and the cable, fundamentally solving the problem of uncontrollable leakage of the liquid-cooled charging gun 22.

[0058] When the leak test is qualified, the action sequence of each component is:

[0059] At step S400, the first electric valve 15 and the second electric valve 16 are fully opened in sequence, and the charging gun 22 is automatically unlocked after a second preset time period, which may be 10 seconds. At this time, the pressure in the closed area of ​​the cooling pipe is completely released, and the user can charge normally.

[0060] If the leak test fails, the following sequence of components occurs: the first electric valve 15 and the second electric valve 16 are fully opened, and the pile body 10 illuminates a fault light or displays "Fault" on the display, alerting the user that charging is not possible. The charging pile system shuts down the charging function and uploads an alarm message.

[0061] Furthermore, in step S100, the circulation pipeline 2 is pre-processed, including:

[0062] S101: The pump 13 runs at the maximum speed for a first running time, wherein the first running time is 20-50 seconds;

[0063] S102: The pump 13 is reduced to the minimum speed and then runs for a second running time, wherein the second running time is 5-15 seconds.

[0064] The maximum rotational speed refers to the highest rotational speed of the pump 13 allowed when the liquid cooling system is running, and the minimum rotational speed refers to the lowest rotational speed of the pump 13 allowed when the liquid cooling system is running.

[0065] In this solution, the coolant flows along the circulation loop of the water pump 13, the expansion hose 14, the first electric valve 15, the water outlet manifold 21, the cooling pipe adapter, the charging gun 22, the cooling pipe adapter, the return water manifold 23, the radiator 11, and the expansion water tank 12. The first electric valve 15 and the second electric valve 16 both adopt electric ball valves. In some implementations, the first electric valve 15 and the second electric valve 16 can adopt electromagnetic butterfly valves, electromagnetic gate valves, etc. The two cooling pipe adapters are respectively connected to the corresponding water inlet and water outlet of the cooling pipe and the charging gun 22. Through the circulation of the coolant, the heat of the charging gun 22 and the cable can be brought to the radiator 11 for dissipation, thereby maintaining the normal operation of the liquid-cooled charging gun 22.

[0066] In this step, specifically, the pump 13 runs at the maximum speed for 30 seconds and then reduces to the minimum speed, and slowly closes the second electric ball valve (second electric valve 16) after 10 seconds. It should be understood that the first operating time and the second operating time can be adaptively adjusted according to actual conditions. For example, the first operating time can be 25 seconds, 35 seconds, 45 seconds, etc., and the second operating time can be 8 seconds, 13 seconds, etc.

[0067] When the liquid cooling system is shut down, the first electric valve 15 and the second electric valve 16 are in the normally open state. When the height of the charging gun 22 and the cable is greater than the height of the water tank of the heat dissipation unit 1, the coolant cannot achieve the function of liquid sealing. The coolant will flow to the lower part under the height pressure difference. At this time, the air in the water tank or other components may rise and enter the cooling pipe. If the air in the cooling pipe is not completely removed, the coolant and air will mix together during the leak detection, which will affect the reliability of the leak detection. Because the expansion coefficients of air and coolant are very different, when the temperature rises or falls, the degree of thermal expansion and contraction of the gas-liquid mixture in the pipe is uncertain. If the ratio between gas and liquid is uncertain, it is impossible to refer to the ideal gas state equation PV=NRT to correct the actual pressure in the cooling pipe, nor can it refer to the liquid expansion coefficient α△t for correction. In this solution, the pump 13 runs at the maximum speed for 30 seconds, and the air bubbles in the cooling pipe can be flushed out into the water tank by a high impact force, so that the cooling pipe is filled with coolant. When leak detection is performed, there will be no additional pressure drop due to air interference, which will make the leak detection inaccurate, and the complete coolant medium can be corrected using the liquid expansion coefficient α△t.

[0068] Furthermore, in step S200, the internal pressure of the circulation pipeline 2 is adjusted to P and then locked, including:

[0069] After the pump 13 is reduced to the minimum speed and runs for the second running time, the second electric valve 16 is slowly closed; at the minimum speed of the pump 13, the pressure in the circulation pipeline 2 can be stabilized and the possibility of bubble generation can be reduced. In addition, the outlet pressure of the pump 13 can be reduced to the lowest, reducing the water hammer impact when the second electric valve 16 is completely closed. Slowly closing the second electric valve 16 can also reduce the water hammer impact when the second electric valve 16 is completely closed.

[0070] Detect the internal pressure of the circulation pipeline 2 and compare the internal pressure of the circulation pipeline 2 with the size of P; if it is less than P, increase the rotation speed of the pump 13 step by step until the internal pressure of the circulation pipeline 2 is equal to P; if it is equal to P, maintain the current rotation speed of the pump 13; if it is greater than P, reduce the rotation speed of the pump 13 step by step until the internal pressure of the circulation pipeline 2 is equal to P; when the maximum head of the pump 13 is greater than Pm, Pm≤P≤Pn, when the maximum head of the pump 13 is less than Pm, P<Pm<Pn; wherein, Pn is the maximum withstand pressure that the cooling pipe in the circulation pipeline 2 can withstand before leaving the factory, and Pm is the maximum long-term allowable working pressure of the circulation pipeline 2; specifically, in this embodiment, the pressure in the circulation pipeline 2 is obtained by the internal pressure sensor thereof, and by implementing this step, the internal pressure of the circulation pipeline 2 can be maintained at P.

[0071] After maintaining the current speed of the pump 13 for a first maintenance period of 10-20 seconds, the first electric valve 15 is closed. After the internal pressure of the circulation pipeline 2 reaches P, the first electric valve 15 is closed after maintaining the first maintenance period, thereby maintaining the pressure in the circulation pipeline 2 stable.

[0072] The cooling tube inside the charging gun 22 cable is not just a cooling tube, it also includes various adapters. For example, a special liquid cooling terminal interface is installed inside the charging gun 22 gun head and is connected to the cooling tube. The gun tail also has a cooling tube interface connected to the water outlet manifold 21 and the water return manifold 23. Adapters are often needed in the above connection process. In the entire liquid cooling circulation system, the pressure resistance of each component and the degree of attenuation of each component during use are different. For example: the pressure resistance Pn of the charging gun 22 cooling tube can reach more than 2MPA, and the pressure resistance Pn of the gun head cooling tube adapter and the gun tail cooling tube adapter can usually only reach 1.5MPA. At this time, the maximum pressure resistance Pn takes the minimum value of each component, that is, 1.5MPA.

[0073] However, during use, the charging gun 22 and the cable will encounter various harsh environments such as falling, dragging, bending, and crushing. The pressure resistance of the cooling pipe and the corresponding adapter will decrease, but the pace of decline is inconsistent. The cooling pipe inside the cable is impacted first, with the most impacts and the worst impact intensity, so the pressure resistance decreases the fastest; the charging gun 22 gun head is impacted second, and the cooling pipe adapter inside the gun head decreases second; the cooling pipe connector at the gun tail decreases the slowest because it is connected to the water outlet manifold 21 and return water manifold 23 of the heat dissipation unit 1. The heat dissipation unit 1 is installed inside the charging pile and is protected by the charging pile shell, so it is least affected by the impact. This inconsistent pace of pressure resistance decline makes it very difficult to define the extent to which the maximum pressure resistance of the entire liquid cooling branch will decrease after long-term operation. It is usually obtained through laboratory testing and named the long-term maximum allowable working pressure, represented by Pm. Obviously, Pn is significantly greater than Pm. Moreover, as the liquid-cooled charging gun 22 is used for a longer time, Pn gradually decays to Pm, and may change from the original 1.5 MPA to 0.8 MPA or even 0.6 MPa.

[0074] To sum up: Leak detection corresponds to maximum withstand pressure detection and maximum working pressure detection, which can better reflect the needs of leak detection.

[0075] It is understandable that the leak detection holding pressure for the liquid-cooled charging gun 22 and cable should be between Pm and Pn. Obviously, the higher the leak detection holding pressure, the stronger the pressure resistance of the liquid-cooled charging gun 22 and cable. They can withstand more harsh operating environments such as falling, dragging, bending, and crushing, without worrying about safety accidents such as leakage and electric shock during charging operations. However, if the liquid-cooled charging gun 22 and cable are only able to withstand the Pm pressure, performing a Pn leak detection will damage them and cause them to be scrapped. Therefore, the leak detection pressure P can be set, that is, Pm≤P≤Pn, to adapt to more application scenarios.

[0076] However, there are not only the above two situations, but also a third situation: when the maximum head of the pump 13 is less than Pm and Pn, during leakage detection, the pressure P is adjusted to the maximum pressure that the pump 13 can provide, that is, P<Pm<Pn.

[0077] Furthermore, in step S300, the preset threshold is a standard threshold K, which is the critical value for the coolant to leak after the pressure drops by K within the rated pressure holding time S when the standard circulation pipeline 2 is locked. Specifically, if ΔP is less than or equal to the standard threshold K, it is determined to be no leakage; if ΔP is greater than the standard threshold K, it is determined to be a leakage. It should be understood that the standard threshold K refers to the critical value for the coolant to leak after the pressure drops by K within the rated pressure holding time S as determined by the laboratory. The rated pressure holding time S is determined by the accuracy of the pressure sensor. The higher the accuracy of the pressure sensor, the shorter the rated pressure holding time S; the lower the accuracy of the pressure sensor, the longer the pressure holding time S. For example, the rated pressure holding time S is 2 hours, the K value is 10,000 Pa, and the corresponding absolute accuracy range of the pressure sensor is ±1,000 Pa. If it is replaced with a pressure sensor with an absolute accuracy range of ±10,000 Pa, the pressure holding time may become 20 hours. Because the accuracy is reduced by 10 times, sufficient time is needed to ensure that a leak is detected.

[0078] Furthermore, the water outlet manifold 21 , the gun head of the charging gun 22 , the gun tail of the charging gun 22 and the water outlet manifold 21 are all provided with temperature sensors, and this embodiment uses a PT1000 temperature sensor.

[0079] In step S300, before detecting whether the pressure drop ΔP in the circulation pipeline 2 exceeds a preset threshold, the following steps are performed:

[0080] Before the locked state of the circulation pipeline 2 is maintained for the first preset time period S, the temperatures of the water outlet manifold 21, the tip of the charging gun 22, the tail of the charging gun 22, and the water outlet manifold 21 are detected;

[0081] After the locked state of the circulation pipeline 2 is maintained for a first preset time period S, the temperatures of the water outlet manifold 21, the tip of the charging gun 22, the tail of the charging gun 22, and the water outlet manifold 21 are detected;

[0082] The difference Δt between the average temperatures of the water outlet manifold 21, the tip of the charging gun 22, the tail of the charging gun 22, and the water outlet manifold 21 before and after maintaining the first preset time S is calculated, and the preset threshold is replaced by K+αΔtP, where α is the expansion coefficient of the coolant.

[0083] It is understandable that since the pressure of the coolant in the cooling pipe is affected by thermal expansion and contraction, the pressure in the cooling pipe will fluctuate to a certain extent. First of all, it should be ensured that the average temperatures monitored by the temperature sensor at the tip of the charging gun 22, the temperature sensor at the tail of the charging gun 22, the temperature sensor at the outlet water distributor 21, and the temperature sensor at the return water distributor 23 are equal before and after the leak detection. However, such equality is relative, and there will still be a temperature difference of several degrees Celsius. At this time, within a smaller temperature difference range, such as 0-5°C, the use of the expansion coefficient for correction can avoid the influence of thermal expansion and contraction on the accuracy of leak detection. That is, when △P>K+α△tP, the leak detection is proved to be unqualified, and when △P≤K+α△tP, the leak detection is proved to be qualified. α refers to the expansion coefficient of the coolant, where the expansion coefficient compensation can be positive or negative compensation, because the corresponding temperature may rise or fall. If the temperature difference range is large, such as greater than 5°C, and if ΔP is significantly greater than K+αΔtP, such as ΔP - (K+αΔtP) > 5αP, then a leak is confirmed. If the difference between ΔP and K+αΔtP is not large, specifically ΔP - (K+αΔtP) ≤ 5αP, then as described below, the pressure is maintained for a second preset time D, which may be 5 S or 10 S. ΔP and (D / S)·K+αΔtP are then compared to determine whether a leak exists. Alternatively, the second preset time D may be divided into multiple time periods D', and ΔP and (D' / S)·K+αΔtP are compared in each time period to determine whether a leak exists.

[0084] Furthermore, as mentioned above, the pressure holding time S refers to the duration of the shortest detection cycle of a leak detection. In actual leak detection, more than one time cycle is often required. It can be understood that the longer the pressure holding time, the higher the accuracy of the leak detection. In particular, when the charging gun 22 is kept in a state of idle pressure, the pressure holding detection time can be extended to 12 hours or even 24 hours. Therefore, the locked state of the circulation pipeline 2 is maintained for the first preset time S, which may include:

[0085] The locked state of circulation line 2 is maintained for a second preset time duration, D, where D ≥ S. The preset threshold is replaced by (D / S)·K+α△tP. When: △P ≤ (D / S)·K+α△tP, the leak test is qualified; △P > (D / S)·K+α△tP, the leak test is unqualified. D refers to the actual pressure holding time.

[0086] In some embodiments, the locked state of the circulation pipeline 2 is maintained for a first preset time period S, and detecting whether the pressure drop ΔP in the circulation pipeline 2 exceeds a preset threshold may include:

[0087] When D / S≥n, the second preset duration is divided into n average holding duration segments, where n is a positive integer;

[0088] Calculate Δt and ΔP for each average pressure holding time period, and determine whether the circulation pipeline 2 is leaking in each average pressure holding time period.

[0089] It can be understood that not only the pressure holding time is accumulated and calculated, but also the pressure holding detection time can be divided into multiple time periods for calculation. For example, when the D / S ratio is ≥2, it is evenly divided into two time periods. When the D / S ratio is greater than ≥3, it is evenly divided into three time periods, that is, n is preferably the positive integer closest to the D / S ratio. Of course, in some implementations, n can also be the positive integer closest to the D / S ratio. And calculate the starting and starting temperature difference and the starting and starting pressure difference of each time period respectively, and then calculate whether there is a leak in each time period respectively. That is, when △P>K+α△tP in any time period, it proves that the leakage test is unqualified. When △P≤K+α△tP in each time period, it proves that the leakage test is qualified. α is the average value of the coolant expansion coefficient. In fact, the change of α at different temperatures is slightly different. The larger △t is, the greater the deviation is. When maintaining pressure in different time periods, there will always be a certain time period when the coolant Δt fluctuates very little, or even Δt < 1°C. The test result at this time can best reflect whether there is a leak in the entire charging gun 22 liquid cooling circulation system. When the test is qualified, the measurement result of the time period with the smallest Δt is used as the final test result. It should be understood that the final test result of each embodiment includes the pressure value after the test, ΔP, the temperature values ​​before and after the test, Δt, the test time, etc.

[0090] It should be understood that both the water outlet manifold 21 and the water return manifold 23 can reserve multiple interfaces, which can be connected to the cooling pipes of different charging guns 22 respectively, or to different cooling pipes on the same charging gun 22, and can also be connected to the installation ports of temperature sensors and pressure sensors.

[0091] The electric valve is in a normally open state. When a remote leakage detection instruction or a leakage detection instruction issued by a predetermined program is detected, the aforementioned leakage detection method is started.

[0092] In this embodiment, the first function of the expansion hose 14 is to mitigate the significant external force applied to the charging gun 22 cable. When the liquid-cooled charging gun 22 is suddenly subjected to tire pressure during charging, the internal pressure in the pipeline from the water outlet of the water pump 13 to the tire pressure section rises sharply, and may even produce a water hammer effect. Because this process is instantaneous, even if a pressure sensor is installed on the outlet manifold, and even if the pump 13 is stopped after detecting excessive pressure, the water hammer will still impact the water pump 13, adapter, and other components due to the delay in such action. In particular, when the water pump 13 is operating at near-maximum speed and the outlet pressure is near Pm, if a wheel suddenly presses against it, water hammer will cause a sharp increase in pressure. With the expansion hose 14 installed, because it is made of an extremely elastic hose, when water hammer occurs, the expansion hose 14 will rapidly expand outward, thereby mitigating the impact of the water hammer on various components and protecting the water pump 13, adapter, and other components.

[0093] The second function of expansion hose 14 is to protect water pump 13 during pressure maintenance testing. As mentioned above, during leak testing, even if pump 13 is running at minimum speed, water hammer is still unavoidable at the moment the second electric ball valve closes, both before and after it closes. Water hammer is also unavoidable at the moment the first electric ball valve closes. However, installing expansion hose 14 significantly mitigates this effect, thereby protecting pump 13.

[0094] It should be noted that the leak detection cycle can be set based on actual conditions, and can be weekly or monthly. For example, if a leak detection interval is set to 30 days, when the 30-day period expires and the charging pile detection charging gun 22 is inserted into the charging gun 22 socket, the electromagnetic self-locking device locks the charging gun 22, and the maintenance indicator light is illuminated or the display screen displays the word "Maintenance". Leak detection can only be performed after the above instructions or actions are completed.

[0095] It should be noted that the present application provides a method for detecting leaks in a liquid-cooled charging gun 22 that can be controlled not only automatically but also remotely or manually on-site. Normally, leak detection should be performed when the charging gun 22 is idle to avoid impacting the customer experience. However, if the charging gun 22 is observed to be damaged or maliciously run over by a car in a video, the charging gun 22 and its cable can receive remote commands or be manually operated by staff to immediately perform a leak detection to determine whether the cooling pipe inside the charging gun 22 and cable is damaged.

[0096] The purpose of self-locking and displaying "maintenance" is to remind the user that the charging gun 22 is in maintenance mode and charging operations are prohibited. It is also to prevent the charging gun 22 and the cable from being subjected to harsh working conditions such as bending and vehicle running over during the leak detection process, which may cause the cooling pipe to burst. Because during the leak detection process, the internal pressure of the cooling pipe has reached the maximum working pressure Pm, or the pressure is above Pm, at this time the two ends of the cooling pipe are locked by the first and second electric ball valves. If it is subjected to harsh working conditions such as bending and vehicle running over, the pressure cannot be released, and it is very easy to burst the pipe, causing damage to the cooling pipe.

[0097] As mentioned above, longer detection time improves leak detection accuracy, but this also impacts the customer experience. Imagine a customer driving to charge their car only to discover that the charging gun 22 is unable to charge due to maintenance. This would be difficult to accept. Therefore, the overlap between customer charging time and leak detection time must be considered.

[0098] Specifically, when the leak detection duration exceeds S (i.e., longer than a minimum charging cycle), the charging station's maintenance indicator light or the "Maintenance" display on the display, among other reminders, ceases, effectively discontinuing the charging gun 22's maintenance status. If the system detects a user scanning a code to charge a new energy vehicle, or if a customer pulls out a charging gun to charge their new energy vehicle, leak detection ceases, allowing the owner to charge their vehicle unimpeded. If no customer is charging, the charging gun 22 continues leak detection.

[0099] During the leak detection process, if the pressure sensor detects a pressure greater than the set maximum detection pressure, leak detection immediately stops and proceeds to step S400. The maximum detection pressure can be set between Pm and Pn. For example, if Pm is 0.6 MPa, Pn is 1.5 MPa, and the leak detection pressure P is set to 0.7 MPa, then the corresponding maximum detection pressure should be between 0.7 MPa and 1.5 MPa, that is, between P and Pn. Due to thermal expansion and contraction, a sudden increase in temperature exceeding the set maximum operating pressure can damage the liquid-cooled charging gun 22. Alternatively, even if the charging gun 22 is plugged into the charging station, the middle portion of the cable is still subject to malicious bending, vehicle overrun, and other accidents. To protect the charging gun 22 and cable from damage, leak detection should be stopped immediately. Once the above steps are completed and the pressure in the pipe is released, leak detection is repeated. If the pressure again exceeds the set maximum detection pressure, step S400 is performed and an alarm is sounded. The alarm can only be cleared after on-site confirmation by personnel.

[0100] It should be understood that the leakage detection method provided in this application can be used alone to detect whether there is a leak in the liquid cooling circulation system of the charging gun 22. Of course, it can also be used in conjunction with a leak detection sensor and a liquid level switch (sensor) to determine whether there is a leak in the circulation pipeline 2 of the liquid-cooled charging gun 22 or a lack of coolant.

[0101] This application is suitable for various coolants, including but not limited to ethylene glycol antifreeze, silicone oil, and electronic fluoride liquid. Although silicone oil and electronic fluoride liquid have insulating properties and will not cause leakage or electric shock accidents even if they leak for a considerable period of time, if leakage continues for a long time, the leaked coolant will continue to accumulate and the silicone oil will deteriorate, which can still cause leakage and electric shock accidents.

[0102] The present application is suitable for various connection methods between the cooling tube and the copper wire, for example: the cooling tube wraps the copper wire, or the copper wire wraps the cooling tube, or the cooling tube and the copper wire are independent of each other.

[0103] The leakage detection method of this solution can be adapted to various conventional liquid cooling circulation systems on the market. The changes to the original heat dissipation unit 1 are very small. Only two electric ball valves need to be added, and the cost increase is limited. The two electric ball valves are installed inside the charging pile and will not occupy the valuable space of the charging gun 22. Moreover, this solution is not affected by the outside world, the probability of failure is very small or non-existent, the detection accuracy is high, and various minor leaks can be detected. In addition, this solution can not only detect leaks, but also test the pressure resistance of the pipeline. It can predict in advance whether the liquid-cooled charging ability to resist falling, dragging, bending, and crushing will decrease, and minimize leakage and electric shock accidents.

[0104] The circulation line 2 between the first electric valve 15 and the second electric valve 16 provided in this application can also include more components prone to leakage and detect whether there are leaks. The type, quantity, and location of the radiator 11, pressure sensor, temperature sensor, and electric valve can be adaptively configured according to actual conditions.

[0105] The number of internal cooling tubes of the liquid-cooled charging gun 22 provided in this application can be in various combinations, including two tubes with one inlet and one outlet, three tubes with one inlet and two outlets, four tubes with two inlets and two outlets, or other combinations. Alternatively, the cooling tubes of two or more charging guns 22 can be installed simultaneously on the water outlet manifold 21 and the water return manifold 23, and leak detection can be performed on multiple liquid-cooled charging guns 22 at the same time. Any such simple replacement is within the scope of protection of this application.

[0106] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for detecting leakage of a liquid cooling pipeline, for detecting leakage of a liquid cooling pipeline, wherein the liquid cooling pipeline comprises a heat dissipation unit and a circulation pipeline connected to the heat dissipation unit at the head and the tail to form a circulation loop, wherein a pressure sensor is provided in the circulation pipeline, and wherein: The leakage detection method comprises the following steps: Pre-treat the circulation pipeline to remove the air in the circulation pipeline; Regulating the internal pressure of the circulation pipeline to P and then locking it; After the locked state of the circulation pipeline is maintained for a first preset time length S, the pressure drop △P in the circulation pipeline is detected to see if it exceeds a preset threshold value. If △P is less than or equal to the preset threshold value, it is determined that there is no leakage; if △P is greater than the preset threshold value, it is determined that there is a leakage; wherein, the first preset time length S is the length of the shortest detection cycle of the leakage detection, and the pressure drop △P is the difference between P and the pressure of the circulation pipeline after the first preset time length S is maintained.

2. The liquid cooling pipeline leakage detection method according to claim 1, characterized in that: The heat dissipation unit includes a pump; the pre-processing of the circulation pipeline includes: The pump runs at the maximum speed for a first running time, wherein the first running time is 20-50 seconds; The pump runs for a second operating time after reducing to a minimum speed, and the second operating time is 5-15s.

3. The liquid cooling pipeline leakage detection method according to claim 2, characterized in that: The heat dissipation unit includes a first electric valve located at the water outlet and a second electric valve located at the water return port. A pressure sensor is provided in the circulation pipeline. The internal pressure of the circulation pipeline is adjusted to P and then locked, including: After the pump is reduced to a minimum speed and runs for a second running time, slowly closing the second electric valve; Detect the internal pressure of the circulation pipeline and compare the internal pressure of the circulation pipeline with P; if it is less than P, increase the rotation speed of the pump step by step until the internal pressure of the circulation pipeline is equal to P; if it is equal to P, maintain the current rotation speed of the pump; if it is greater than P, reduce the rotation speed of the pump step by step until the internal pressure of the circulation pipeline is equal to P; when the maximum head of the pump is greater than Pm, Pm≤P≤Pn, when the maximum head of the pump is less than Pm, P<Pm<Pn; wherein Pn is the maximum withstand pressure that the cooling pipe in the circulation pipeline can withstand before leaving the factory, and Pm is the maximum long-term allowable working pressure of the circulation pipeline; After maintaining the current speed of the pump for a first maintaining time, the first electric valve is closed; the first maintaining time is 10-20s.

4. The liquid cooling pipeline leakage detection method according to claim 1, characterized in that: The preset threshold is a standard threshold K, and the standard threshold K is a critical value at which there is no coolant leakage after the pressure drops by K within the rated pressure holding time S in a standard circulating pipeline locked state.

5. The liquid cooling pipeline leakage detection method according to claim 4, characterized in that: The circulation pipeline includes a water outlet manifold, a charging gun and a water return manifold which are sequentially connected between the water outlet and the water inlet of the heat dissipation unit, and the water outlet manifold, the gun head of the charging gun, the gun tail of the charging gun and the water outlet manifold are all provided with temperature sensors; Before detecting whether the pressure drop ΔP in the circulation pipeline exceeds a preset threshold, the method includes: Before the locked state of the circulation pipeline is maintained for a first preset time length S, detecting the temperatures of the water outlet manifold, the gun head of the charging gun, the gun tail of the charging gun, and the water outlet manifold; After the locked state of the circulation pipeline is maintained for a first preset time period S, detecting the temperatures of the water outlet manifold, the gun head of the charging gun, the gun tail of the charging gun, and the water outlet manifold; The difference △t between the average temperatures of the water outlet manifold, the gun head of the charging gun, the gun tail of the charging gun and the water outlet manifold before and after maintaining the first preset time length S is calculated, and the preset threshold is replaced by K+α△tP, where α is the expansion coefficient of the coolant.

6. The liquid cooling pipeline leakage detection method according to claim 5, characterized in that: The locked state of the circulation pipeline is maintained for a first preset time period S, including: The locked state of the circulation pipeline is maintained for a second preset time length D, D≥S, and the preset threshold is replaced by (D / S)·K+α△tP.

7. The liquid cooling pipeline leakage detection method according to claim 6, characterized in that: The locked state of the circulation pipeline is maintained for a first preset time length S, and detecting whether the pressure drop ΔP in the circulation pipeline exceeds a preset threshold value includes: When D / S≥n, the second preset duration is divided into n average pressure holding duration segments, where n is a positive integer; Δt and ΔP of each average pressure-maintaining time segment are calculated respectively, and it is determined whether the circulation pipeline is leaking in each average pressure-maintaining time segment.

8. A liquid cooling system, characterized in that: It includes a heat dissipation unit and a circulation pipeline connected to the heat dissipation unit at both ends to form a circulation loop; the heat dissipation unit includes a first electric valve located at the water outlet, a second electric valve located at the water return outlet, and a pump, an expansion water tank, an expansion hose and a radiator connected to the loop between the first electric valve and the second electric valve; the circulation loop includes a water outlet manifold, a charging gun and a water return manifold connected in sequence between the water outlet and the water inlet of the heat dissipation unit, and a pressure sensor is provided on the circulation loop side of the water outlet manifold or the water return manifold.

9. The liquid cooling system according to claim 8, characterized in that: The water outlet manifold, the gun head of the charging gun, the gun tail of the charging gun and the water outlet manifold are all provided with temperature sensors.

10. A charging pile, characterized in that: It comprises a pile body and a liquid cooling system as claimed in claim 8 or 9, wherein the heat dissipation unit is installed inside the pile body, the charging gun and the pile body are detachably assembled, and the pile body is provided with a self-locking device for locking the charging gun; The liquid cooling system is detected by using the leakage detection method according to any one of claims 1 to 7. When the leakage detection method is performed and after a leak is detected, the self-locking device locks the charging gun to prohibit charging.

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